A Year of mHam 2.0 - Three Observations with host Dr. Brad Lewis

A retrospective look at the Modified Ham (mHam 2.0) Complement-Dependent Cell Killing Assay, one year after its release.

Don't forget, this test has a STAT TAT of < 24 hours (M-F).

Visit ➡️ https://mham.machaondiagnostics.com/ to learn more. 

Episode Transcript

SPEAKER_00 (00:05):
Hello and welcome to Blood, Sweat, and Smears, your
Macheon Diagnostics podcast withtag team hosts, including our
medical director, Dr.
Brad Lewis, Senior DirectorBjorn Stromsis, that's me, and
other guest hosts.
We hope you find these podcastsinteresting and informative.
Thank you for listening, andaway we go.

SPEAKER_01 (00:26):
Welcome to another sort of episode in the Blood,
Sweat, and Smears series ofpodcasts, but this one is
obviously a webinar, so it's alittle bit different.
Wanted to talk a little bitabout a new test we're offering
called the Modified Ham test.
And in particular, I want totalk about the test itself, but
I also want to talk about someobservations we've had now that
we've had this test going forabout eight months, nine months

(00:48):
or so.
So it's a bit of an over of alook back to see what have we
learned about this really verynovel test.
So I want to, before I talkabout the M Ham, I wanted to
take a step back just a littlebit and talk about why you care
about the modified ham test.
And the reason you care isbecause there is a group of
disorders called thromboticmicroangiopathies.

(01:10):
This is really a pathologicdiagnosis.
It's swelling of the lining ofsmall blood vessels that causes
platelets to stick and thenfibrin formation and shredding
of red cells as they go throughthat.
But hematologists have a hubristhat allows us to believe that
we can make pathologic diagnosesjust by looking at the blood.
Am I always right?
No, not quite, but close enoughfor hematology purposes.

(01:32):
So what I used to say to myresidents is every time you see
a case of anemia andthrombocytopenia in a sick
patient, that is a thromboticmicroangiopathy.
Is that true?
No, that is not true.
Most of the time it's not, butthis is uncommon enough and it's
important enough to recognizethrombotic microangiopathies,
that I think every time you seea case of anemia and

(01:54):
thrombocytopenia, you ought toat least stop for a split second
and ask, could this be my chanceto see a thrombotic
microangiopathy?
Then what you want to know isdoes it meet the criteria?
Does it have thrombocytopenia?
Need not be severe.
In fact, the thrombocytopenia,depending on which thrombotic
microangiopathy it is, may ormay not even track with the
severity of the thromboticmicroangiopathy, which I'm going

(02:16):
to call a TMA from here on.
There should be an anemia, butnot any old anemia.
It should be a microangiopathichemolytic anemia.
Red cells that are beingshredded in the microvasculature
in that process I describedearlier on.
Ideally, there would beschistocytes.
That's what you see here.
Red cells which have beenshredded.
They're not there maybe 25% ofthe time overall in TMAs, and

(02:41):
it's worse in some particularkinds.
Post-bone marrow transplantTMAs, for example, in
pediatrics, 50% of the kids maynot have schistocytes, at least
not initially.
Other signs that you have a mahawhen you don't see schistocytes
are that the LDH, which is beingreleased from these cells, is
very high because thedestruction is happening
intravascularly, unlike so manyother hemolytic anemias, where

(03:04):
the destruction happens in thespleen, in the liver, in the
bone marrow, someplace whereyour body is able to handle the
detritus better.
So the LDH and stuff doesn'tcope as much.
Similarly, the haptoglobin istypically low because hemoglobin
is being released and it's beingmopped up by the haptoglobin,
then that complex is beingexcreted.
Be aware, though, thathaptoglobin is an acute phase

(03:25):
reactant.
So sick patient with a TMA,often the story, the sick
patient part may elevate theirhaptoglobin, and then the TMA
lowers their haptoglobin andthey end up being normal or low
normal.
And then for research studies,certainly, you want to see some
organ damage.
You know, we kind of hope thatsometimes we can make this
diagnosis even before there's alot of organ damage and try to

(03:46):
head that off.
And kidneys tend to be thecanary in the mind.
So you've made the diagnosis ofTMA.
The next step is to begin to gothrough the differential.
And for those of you who arenewer to medicine, this is not
something you need to copy down.
This is in every resource youcould choose to look at.
You can find a differential.
Typically, we worry about TTPand atypical HUS because they're

(04:10):
both rare, very severe, oftenfatal, and they both have great
therapies when they are treated.
So we worry about these.
Although I don't mean tobelittle the severity of any of
the rest of these things I'mabout to talk about.
If the patient has diarrhea,then we worry about
toxin-induced HUS, which soundslike it's related to AHUS, but
is not really.

(04:31):
And this is induced by toxigenicbacteria, typically E.
coli, but Chigella andpneumococcide do it
occasionally.
Very, very unlikely if thepatient doesn't have diarrhea.
Although I've had a few caseswhere they kind of ran out of
diarrhea, but that's anotherstory.
There are some rare congenitalcauses of TMAs.
Typically, these are diagnosedbecause patients look like they

(04:51):
have atypical HUS.
They didn't get better the waythey were supposed to.
So you get genetics trying tosort things out, and then you
find DGKE deficiency, cobalaminC deficiency, occasionally
severe G6PD deficiency,congenital TTP can sometimes get
in there and fool you a littlebit.
And then there's another storyreally about immunologic
heperinduced thrombocytopenia.

(05:12):
That leaves us with this othergroup of other possibilities.
These are all interestingbecause everything here causes a
TMA.
Everything here also can triggeratypical HUS.
So it can be confusingsometimes.
And patients often present withone from column A and one from
column B simultaneously.
But DIC, mechanical destructionof the cells, which typically

(05:36):
does not trigger AHUS, by theway.
Malignant hypertension, which isa triple threat.
It triggers AHUS, it looks likeAHUS, and refractory
hypertension is one of the morecommon manifestations of AHUS.
Lupus, scleroderma, othersimilar autoimmune disorders can
also cause TMAs.
We'll get come to that a littlebit when we look at some of our

(05:57):
data.
Catastrophic or thromboticlupusanoagulant disorders,
catastrophic antiphospholipidsyndrome, that too, which may
also be complement mediated, butthat too can cause a TMA.
Pregnancy-related TMAs, HELPsyndrome, pre-eclampsia, those
may also be somewhat complementtriggered.
That's a work in progress, Ithink, right now.
Infections of every sort.

(06:19):
Bacterial infections, obviously,if they're overwhelming
bacterial infections, the kindthat give you DIC, we expect to
see a TMA, but milder infectionscan do it sometimes.
Protozoal infections, acid-fastbacteria, TB can do it.
You name it, malaria does it,lots of infections can do it,
viral infections, COVID, HIV,CMV, for example.

(06:41):
Malignancies can do it.
Usually these are advancedmalignancies.
Occasionally it can be the firstmanifestation of a malignancy.
Gastric cancer is notorious forthat.
Graft rejection and drugs,calcinurin inhibitors,
gemcitabine, and a number ofother drugs can also cause TMAs.
So you've got a differential towork through.
Most of the time, this is a verystraightforward differential.

(07:09):
So before I talk more about ourdata, just real quickly to look
at this cartoonized version ofthe complement cascade, a couple
of points I wanted to make.
One is that at the bottom of thecomplement cascade, you cleave
C5, C5B attaches itself to thecell membrane, it then assembles
C6, C7, C8, and C9, forming acomplex that destroys or punches

(07:33):
holes through the cell membrane.
That creates the C5B through 9complex, most commonly by me at
least, called the membraneattack complex.
The way that comes to be aproblem in atypical HUS is that
this cascade is very efficient.
And to keep it in check, youhave a number of inhibitors.

(07:53):
Atypical HUS is typically afunctional defect in one of the
inhibiting factors of thecomplement cascade, allowing the
cascade, when it's stimulated,to sometimes get overstimulated
and out of control.
Similarly, it can be a gain offunction mutation in one of the
stimulators of the complementcascade.
So that when the cascade istriggered by something, it then

(08:15):
takes off.
Now that may not take a lot oftrigger.
The alternative pathway isalways on, for example, but
antibodies can trigger thepathway with the autoimmune
diseases we talked about,infections and malignancies.
The antibodies can trigger itvia the classical pathway.
Infections, malignancies cantrigger it via the lectin
pathway.
Also, anything triggers thecomplement cascade, you then

(08:35):
require the inhibitors to keepit in check.
If you don't keep it in check,then you begin to cleave too
much C5 and you begin to haveattacks on the on various
membranes with kidneys being aparticularly sensitive
substrate.
So what is this MHAM test wetalked about?
Let me just, because I get somany calls, asking me the

(08:56):
question why is it called MHAM?
This is not a ham test.
The ham test was actually a testdeveloped years ago as a way of
diagnosing the very raredisorder, paroxysmal nocturnal
hemoglobin urea.
And you took the patient's redcells, which were very sensitive
to complement destruction, andyou added in serum with
complement in it in a situationthat was very conducive to

(09:19):
activation of the complement andlooked for destruction of the
red cells.
That's not what we're reallylooking at.
We are not trying to diagnosePNH here.
The original MHAM test, however,was a red cell that was modified
to make it very sensitive tocomplement.
So we took our red cells, notthe patient's red cells, added
the patient's serum on top ofthat, and looked to see if the

(09:42):
patient's serum was able tolysensitized red cells.
That turned out to be adifficult test to scale up, but
a version of that, a nextgeneration version of it, if you
will, was to develop abioluminescent immortal renal
cell.
So these are no longer redcells, they're now renal cells.
They're bioluminescent whenthey're alive.

(10:03):
It's an energy requiringprocess.
When they die, they stopluminescence.
So it lets us follow theiractivity, if you will.
And then these are modifiable,and these renal cells have been
modified to remove one oranother or many surface proteins
which protect the cells againstcomplement.
For our purposes, removing CD46,CD46 knockouts, if you will,

(10:26):
makes the cells appropriatelysensitive to complement
destruction to give ussensitivity and specificity of
this test for atypical HUS.
We then take these immortalizedbioluminescent cells and we add
heat-treated plasma.
Heat treatment destroys thecomplement, so very few are
destroyed.
You can add in normal plasma.

(10:48):
And when you do, there's alittle bit of destruction, but
not a lot.
There's complement activity innormal plasma, normal serum,
really, but not an enormousamount.
And then we add in, or if we addin AHUS, then the activation of
the complement will destroy alot.
Our cutoff is if you destroymore than about 60% of the of

(11:10):
the cells, getting less than 40%viability, you clearly have a
typical H2S, or clearly have anabnormal complement mediated
disorder.
So this complement biosensortest, or more and more we call
it the biosensor MHAM test,measures the ability of patient
serum to destroy target renalcells.

(11:31):
So you're looking, it's afunctional test looking at the
ability of the patient's serumto destroy cells.
We can adjust the sensitivity,and we've done that with our
CD46 knockout.
It's similar conceptually inthat it looks at complement
activation to the soluble C5Bthrough 9 or soluble MAC test,
which many of you may be morefamiliar with, but it's quite
different.

(11:51):
This test, the M HAM, is afunctional assay.
It's looking at the ability ofthe patient's serum to destroy
renal cells.
It's looking at exactly whatyou're interested in.
The soluble MAC, soluble C5Bthrough 9, is a byproduct.
You're measuring C5B through 9,which was bound by vitrinectin
and some other stuff,inactivated and solubilized,
stabilized, making it easier forus to measure it, but it's a

(12:15):
byproduct.
It doesn't measure the abilityof the serum and with all the
things that are involved in thatto destroy renal cells.
I believe that this complementbiosensor test we offer is the
first commercially availablefunctional assay.
I believe there are some othersthat have also come on.
It's very similar to thefunctional testing that you
might read about in Italy, inChapel Hill out in Iowa, out of

(12:36):
the University of Iowa, but ourtest is reliable and scalable.
There are others are reliable.
I'm not so sure about thescalable, and ours is quickly
available with a 24-hourturnaround.
This is from an article writtenby Michael Cole and his group
out of Johns Hopkins.
They developed the modified hamtest as well as the
bioluminescent modified hamtest.

(12:57):
And this is just two graphs thatshow the same thing.
This makes the point that we canfollow the activity of the cells
over time.
We don't do that as part of ourroutine testing.
This looks at it in a staticway, but notice here if you add
normal human serum, there's somecell killing, but it doesn't
cross the abnormal threshold.
If you look at patients withatypical HUS, there's a lot of

(13:19):
cell killing that's caused.
If you add Eculismab back intothe in vitro, you then abrogate
the cell killing.
So we can prove in vitro, and wedo with every assay, we we show
not only that there's beendestruction, but that we can
abrogate the destruction byadding in Eculismab.
If you look at patients who haveAHUS who are on therapy

(13:40):
receiving a C5 blocker,Eculismab or Aulismab, then
indeed you you do normalize thatthe cell killing in those
patients also.
So what's the utility of thisMHAM testing?
Obviously, it appears to have atremendous utility for the
diagnosis of AHUS.
It's still a fairly new test,but it appears to be both a bit
more sensitive than the solubleMAC or soluble C5B through 9 at

(14:04):
diagnosing AHUS andsimultaneously more specific for
AHUS, although it's alsopositive with thrombotic lupus
anticoagulants and maybe someother disorders like Help
syndrome, but it does appear tobe more specific for AHUS and
AHUS-like disorders.
Appears to separate pretty wellfrom other complement-mediated

(14:24):
disorders that might have TMAs,things like lupus and
scleroderma, sepsis, andmalignancy that I mentioned
earlier on.
Similarly, if the test comesback negative, it makes the
diagnosis of AHUS much lesslikely.
And as I'll mention in one ofthe cases that we have, it makes
you go back to the drawing boardand ask whether we might have

(14:46):
missed something else that'scausing this TMA.
It also is useful because inmany patients it's positive in
remission.
So, for example, in assessing apatient before a renal
transplant, they're geneticallypositive, that makes it easy.
But 60% of people with seeminglygenetic AHUS who respond to
therapy will have negativegenetics.

(15:09):
Another way to evaluate thosepatients, even when they're in
remission, is with the modifiedAM test, which is often
abnormal.
We're not using this a lot, butit also would be potentially
useful in evaluating variants ofunknown significance.
It's positive in manyasymptomatic carriers of genes
that cause atypical HUS, and itallows you to do trio testing,

(15:29):
looking at the proband as wellas the proband's parents, even
with genetically negativedisease, looking to see which
parent is carrying the defectand to track genes to perhaps be
able to show that some of theseVUSs are actually
disease-causing variants.
And we didn't talk about it, butyou can within the modified ham
test also isolate individualcomplement pathways, the

(15:51):
classical pathway, the lectinpathway, as well as the
alternative pathway, to look atwhich pathway is really carrying
a defect, again, allowing us tohone in on variants in pathways
other than the alternativepathway.
So this were our results fromthe first eight months or so.
I think you have about 170samples in here.
The first thing that jumps outat me, at least, is it was an

(16:15):
interesting social phenomenagoing on.
So on the y-axis here, you haveviability of the cells.
So this is normal to have 100%viability.
And when you have less than 60%viability, it becomes
interesting.
When it's less than 46%viability, you actually have a
clear-cut positive.

(16:36):
So the majority of the sampleswe got during our first eight
months, as you can see, came upwith normal modified ham tests.
We simultaneously were runningthe non-functional assay, the
soluble C5B through 9 or solubleMAC levels.
And you can see that many ofthese patients had positive
soluble MACs.
So why are we not seeingpositive M HAMS?

(16:58):
I think what you're seeing herein some large extent was a
social phenomena.
We've gone back and talked to asmany of these physicians as we
could to find out about whothese patients were.
And so far, no one with atypicalHUS had come in with a negative
modified hand test, except for afew where they were already on
therapy.
And indeed, the modified handtest normalizes, as does the

(17:20):
soluble MAC, once you go ontherapy and those patients show
up in the space.
But I think what was happeningwas the calls I was getting was
look, I've got this patient.
If I really thought it was AHAS,I'd just have him on therapy.
But I I don't really think it'sAHUS, but I'm just concerned
about that possibility.
Could we get a modified hamtest?
And the vast majority of thosecases where they didn't really

(17:43):
think that it was it was AHAS,it wasn't AHAS, it was something
else.
And I'll show you a littlesmattering at least of what some
of those other things were.
So one of the patients who had avery high soluble MAC had had
lupus.
And they were concerned becausethere was more hemolysis than
you generally expect with theTMA that's often seen in

(18:04):
association with lupus.
But this patient did not haveatypical HUS.
Similarly, this other green dotwas another patient who had
known HLH, again with morehemolysis than you generally
expect.
Obviously, you can seehemolysis, but you know, that's
why they have us.
That's why you have physicianstaking care of these people, is
that your clinical judgmentsometimes steps in, and this

(18:26):
seemed like more hemolysis thanyou might really expect.
But indeed, this patient alsodid not have atypical HUS.
And this case was actually very,very interesting.
In that little green dot was apatient who'd come in with a TMA
as well as some renal disease,got a biopsy of his kidney, and
on that biopsy had clear-cutTMA.

(18:49):
So now it really looked likethis was atypical HUS.
We ordered our testing, and asyou can see, both the soluble
MAC and the MAM are normal inthis patient, which caused us to
go back to the drawing board andlook for other possibilities.
And on scan, this patient wasfound to have a very large
prostate abscess, and process,the pathologic process, went

(19:11):
away when this abscess wasdrained and the patient was
treated.
So, what about the soluble MAC?
Has it been kicked to the sideof the road?
No, not yet.
It's a cheaper test than themodified ham test is.
It's the the only test which hasbeen shown that when it's
negative at the echulysomabtrough, the risk of relapse if

(19:31):
you stop therapy is very low.
In a study from Furkuri and hisgroup from a few years back.
So it may be useful at trying todecide if the patient can stop
therapy.
The modified hand test may alsoturn out to be useful for that,
but not yet been clearly shown.
If a patient is on echulysmab,one of the questions that comes
up is is this dose effective?
Can I decrease the dose?

(19:52):
And if the patient is startingto have some symptoms or some
signs, is it possible that thedose needs to be increased over
the usual dose?
Um, using the cyboMAC allows fordose adjustment.
It's fully suppressed when youhave an effective dose of
aculismab on board.
And then interestingly, it iselevated in cases of non-AHUS
complement activation, lupusmaligncy, sepsis.

(20:15):
What that means in terms oftherapy downstream, especially
as we get more targetedtherapies for different
complement pathways, that's upin the air at this point.
What's the value of a positive MHAM test?
I think the value is, like yousee here, this patient was
positive on everything, positivegenetics, positive soluble MAC,

(20:36):
positive M HAM test.
This patient has AHUS, and hehad a positive biopsy, too, if I
remember correctly.
This just confirms what weprobably could have guessed in
other ways.
Um, this patient had a solubleMAC that was a little bit more
equivocal, but a very positivemodified ham test, allowing to
start therapy right away.

(20:57):
This case and a number of othercases also raised another thing
I just wanted to comment on.
Obviously, we do stat geneticshere at Maycheon, and I'm a fan
of genetics.
I think they have a role inAHUS, but that role is not
usually the role of diagnosis.
Occasionally we do lean on itwhen we're really, really
confused.
But only 40%, maybe less, ofpatients who have AHAS will have

(21:21):
positive genetics.
So if they're positive, that'sincredibly useful in a confusing
case.
But negative genetics do notchange my mind.
If I think somebody has AHUS,they still have AHUS.
So once I've decided somebodyhas AHUS, I don't wait for
genetics ever.
Once I've decided, I go aheadand treat.
If I'm really confused, my go-towould be the modified ham test

(21:42):
as a way of sorting that out.
And obviously that's whathappened here.
But waiting for genetics isalmost always a mistake in these
cases.
This was a patient who I believewas going to be going to
transplant, if I remembercorrectly now, who had negative
genetics and had come offtherapy, because that's quite
safe when your genetics isnegative, but it's not
completely safe.

(22:03):
And indeed, he had relapsed.
And the modified ham testconfirmed that this patient had
AHUS now in relapse and is nolonger a candidate really for
coming off therapy.
So a positive test clearly isuseful.
We've had so far no falsepositive tests.
One other thing I wanted to talkabout before I close here.

(22:24):
One of the things we had noticedis that triglycerides appeared
to be interfering.
So we did a in vitro study, wehad some normal samples and we
had some known abnormals.
If you look at these samplesstraight out, the normal
obviously has normal viabilityat 98%.
And our AHUS patient had only a15% viability.

(22:46):
If you add in hemoglobin,nothing really happens.

(23:08):
So we have a falsely normalsample with these high
triglycerides.
Then the question is, is thatonly going to happen with four
plus triglycerides, or is itgoing to happen with lower
levels of triglycerides?
So we looked at lower levels.
Our one plus triglycerides arestill visible to us, but it's a
very modest treatment oftriglycerides.
And that moves an abnormalsample from, in this case, a

(23:31):
clearly abnormal 22% to a barelyabnormal 42%.
So it's a substantial andclinically meaningful change in
the result that we got.
With two plus spiking of thetube, the normals remained
normal, but our abnormal samplebecame an equivocal sample
bordering on being a normalsample.

(23:53):
So it's made a huge difference.
And it's a dose-relateddifference.
Obviously, the moretriglycerides there are, the
more normal the sample becomes.
That's the bad news.
The good news is we've so faronly seen two patients with
visible triglycerides out of the185 or 190 samples that we've
done so far.

(24:13):
So this is not a common problem.
But if you send us a sample andwe see triglycerides, you will
get back a report, noting thatwe don't trust this sample,
particularly if it's equivocalor borderline normal.
We'll be wondering about thepossibility of it being an
abnormal sample.
We are looking right now at waysto abrogate this phenomena.
We have not developed one yet,but we're working on that.

(24:36):
So again, a great new test.
Looks as though the modified hamtest is going to offer us both
sensitivity and specificity indiagnosing atypical HUS.
Um, this triglyceride problem sofar has not been a clinically
bothersome problem for very manypatients.
But again, an interesting newtest.
So thank you very much forcoming along.

(24:57):
I do have some questions.

First question (24:58):
how confident would I be in a patient with
transplant associated TMA to nottreat with Eculismab in the
setting of a negative MHAM?
I think we don't have enoughdata so that if I really thought
that someone had atransplant-associated TMA with
an elevated, you know, solubleMAC and meeting the other

(25:20):
criteria that Jodell has haspublished on.
And it looks like they have atransplant-associated complement
mediated TMA, I would probablytreat that patient at this point
in time.
I just don't have a lot of datain that setting on the possible
false, false negativity ofMHAMS.
Hopefully, I will get to thatpoint at some point.

(25:44):
Why is 60% used as a cutoff?
That just turns out to work.
We see virtually no one who'sabnormal with a viability above
60%.
In the 60% to 46.5% range, it'sa little bit equivocal.
We've had some people go eachboth ways.
Below 46.5% viability of thecells, everybody so far has had

(26:08):
atypical HUS and appears to bevery sensitive using those
cutoffs.
That's just empirically pickedfrom the results that we've been
getting.
So I actually don't know how ourspiking correlates with
biological levels oftriglyceride, embarrassingly.
The levels were picked tocorrelate roughly with the kinds
of triglyceride levels you see.

(26:29):
What I can say is that we seesome but very modest
interference at a level oftriglyceride one plus that we
are able to see visually.
So we can for now easily screenfor meaningful elevation in
triglycerides.
Hopefully, we'll find a way toremove that.
But again, has not been aproblem much.

(26:49):
So you know, half a percent orso of patients have had
significant triglycerides.
Someone else asked the a veryappropriate question that has
modified ham test been validatedwith renal limited TMA?
No, it has not.
There's nothing that's been welllooked at yet for the
renal-limited TMA.

(27:10):
That whole field is a bit of awork in progress.
So someone notes, hi Rita, it'snice to hear from you.
Someone notes that they'rehaving trouble getting this test
done as an outpatient.
It is a problem.
Talk to us when that comes up.
I believe we do have someresources for I'm getting a yes,
I'm looking out of the corner ofmy eye here.
We do have some resources forgetting those tests paid for

(27:31):
when insurance won't in inoutpatients.
It's obviously much easier, andmost of our testing, because of
the nature of this testing, hasbeen on inpatients.
But call us, talk to us if youhave a patient.
We do pretty darn well atfinding resources most of the
time.
What do I think of the Prismaxscore?
I'm now I'm really embarrassed.
I don't know the Prismax score.

(27:53):
Is that like the plasma scorefor TTP, which I don't find
particularly useful?
They've just codified the seatof my pants, basically.
They said the things that wewould all normally look for, and
then they put them into a scale,but it's easy enough to just
look at it and say this patientdoes or does not meet the
criteria for TTP.
And there are enough, there'senough slop in that that

(28:13):
personally I get an ADM TS-13 oneverybody uh in that setting.
And it's quick and easy.
We have a 24-hour turnaround forthat test.
It's quick and easy, and itsolves the problem.
Experience with MHAM in delayedhemolytic transfusion reaction
in sickle cell patients.
No, this is actually somethingwe're very interested in.
We have not, and no one I knowyet has been looking at the MHAM

(28:36):
in a one is published, lookingat the MAM in various sorts of
sickle cell crises, although wedo have more and more data
coming in, including somefunctional testing of the
complement cascade, suggestingthat complement is involved in
sickle cell crises, particularlyin the hemolytic crises.
Does the threshold for positiveor negative help us?

(28:57):
Not yet.
For now, when they're positive,they're positive, and when
they're not, they're not.
And I don't know what verypositive means in this setting.
It makes me think that thepatient has more complement
activity, but I don't have, andI think no one has enough data
right now to say what thatreally tells me in terms of what
I'm going to be doing.
And then I do expect the MHAM tofully normalize with therapy.

(29:20):
So one of the things it tells meis that the patient is not on
therapy, or at least not onclinically effective therapy.
Rita, I'm embarrassed.
I don't know that score.
I think that may be the end ofthe questions that are coming
in.
The result is reported as apositive or negative, and you
will be given the percentviability.
Someone asks.

(29:42):
I have a question that just camein.
Oh, sensitive.
So again, I think these testsare new enough.
You've seen the data that wehave.
There's also the experience outof Johns Hopkins.
The test appears to be verysensitive.
90%, 95% is a number that's beenthrown around.
I think we don't have any goodbig Big studies yet to really
begin to look at this.

(30:02):
I can only tell you that of thepatients that I showed you, we
had no positives that we areaware of in patients who had
negative M HAM tests, unlessthey were already on therapy,
which has happened.
And it should have been obviousfrom what I was saying already,
but an MAM test in a patient ontherapy, unless you're looking
to assess the efficacy oftherapy, is not a useful test.

(30:24):
It needs to be done off therapy.
If you're thinking, especiallyabout using one of the
long-acting C5 blockers, it'sworth getting that MHAM test,
even if it's only as a baselineto know what's going on with
this patient in case you needsomething to compare to down the
road.
Once you put them on along-acting C5 blocker, it's
very hard really to get a goodresult on this at this point in
time.
We're working on ways to get ridof C5 blockers in the assay, but

(30:48):
don't have anything currentlyavailable.
So someone asks about thehandling of the sample with
pre-analytic variables that aresuch a bugaboo in our business.
We asked that the sample beprocessed within a couple hours
of being drawn and then theserum sample removed and frozen.
When we've looked, it reallybetween you and me, despite what

(31:08):
it says, it looks as thoughthese samples are quite stable
at room temperature andrelatively resistant to
mishandling in terms of changingthe values.
It would appear that if youmishandle the samples, the MMA
might become more normal, whilethe soluble MAC becomes more
abnormal with the same kind ofmishandling.
But again, the MHAM appears tobe quite a robust test.

(31:30):
Someone asked if I can share thereference for the cyuble MAC's
utility in assessing the risk ofrelapse when stopping therapy in
patients with AHS on therapy.
I am not sitting here with myreferences.
The author is Fakuri.
It was published right around2023.
And the title is something likethe utility of genetic testing

(31:55):
for stopping treatment of AHS.
It's something like that.
If you want to send me an email,as soon as I get off here, I can
pull up my end note and get youthat specific reference.
And there's a lot of references,a lot of articles by Fer Curry,
but Fer Curry is the firstauthor on this one.
But if you send me an email, I'mhappy to send you the reference.
And it's really about genetics,but it also notes that if they

(32:19):
checked the cyboMAC at TROF,these were patients on
Echulysimab at their Trough, apositive test had the same
significance as positivegenetics, and a negative test
had the same significance interms of risk of relapse as
negative genetics.
And this was done in a subset ofpatients in what was really
meant to be a genetic study.

(32:39):
All right.
You guys have one more moment tosend in some questions.
Right.
If you get more questions, I'mvery happy.
Most of you on here have myphone number, my cell phone
number.
Um it's on the Machion website,I believe.
And you're welcome to call me.
You're also welcome to send mean email, also on the Macheon
website, but Brad.lewis atMacheon Diagnostics.com.

(33:03):
I'm always happy to hear frompeople.
I'm happy to talk about patientsbefore you order tests as well
as after you've ordered ourtests.
If you want to talk about whatsort of testing might be useful
in a given patient.
And as some of you know, I'mhappy to talk about patients,
period.
I'm always happy to talk.
Okay.
With that, thank you all verymuch.
I look forward to doing anotherone of these very soon.

(33:25):
Thank you.

SPEAKER_00 (33:28):
That's it for us here at Blood Sweat and Smears,
a podcast produced by MachionDiagnostics, your reference lab
and CRO specializing inthrombosis, hemostasis, and rare
disease.
Thank you for listening.
And if you have a question orcomment or there's a topic you'd
like Dr.
Lewis to speak to, please sendus an email to BloodSweat and
Smears at MachionDiagnostics.com.

(33:50):
That's M-A-C-H-A-O-Ndiagnostics.com.
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