[CIS-PAGID] low ch50 with normal complement levels?

[Anete S Grumach]

Dear Ashish,

Besides evaluating alternative pathway, I would check C3d in order to
differentiate from a primary defect.
Did you check consanguinity  in the family? Which ethnic background?
The most severe form of auto immunity in these patients is related to C1q
def regarding classical pathway, so it is possible that they are
oligosymptomatic until now.

Sincereley

Anete

Anete S Grumach, MD, PhD
Faculty of Medicine ABC, São Paulo
Center of Disease Control, São Paulo City
anete at grumach.com
55.11.83353860

2010/11/16 Anita Gewurz <agewurz at rush.edu>


> Dear Ashish,

>

> Like Drs. Vasconceles and Gonzalez, I suspect the problem is homozygous C2

> deficiency and would also check the AH50.

>

> Undetectable CH50 levels can certainly result from complement activation,

> as suggested by Dr. Verbsky, but in the situation you describe a congenital

> C defect is most likely.  Homozygous deficiency of an early-acting classical

> or mannose-binding lectin pathway component may present in infancy with

> infection or lupus-like disease.  Normal alternative pathway hemolytic

> activity (AH50) excludes deficiency of C3, C5, C6, C7, C8 or C9.

>

> Patricia Giclas PhD, Director of the Complement Laboratory at National

> Jewish can help

> http://www.nationaljewish.org/research/diagnostics/adx/labs/complement.aspx.

>

> Sincerely,

>

> Anita Gewurz MD

> Section of Allergy and Immunology

> Department of Immunology/Microbiology

> Rush Medical College

> Chicago IL 60612

>

>

>

> On Nov 15, 2010, at 7:11 PM, <dmvascon at usp.br> wrote:

>

>  Dear Ashish

>>

>> I would suggest to test for APH50, in order to evaluate alternate pathway

>> function. The combination of both functional screening tests (CH50 and

>> APH50) is very useful to drive the evaluation of complement defects:

>>

>> CH50 indetectable, APH50 normal: defects of classical pathway activation

>> CH50 normal, APH50 indetectable: defects of alternate pathway activation

>> CH50 and APH50 indetectable: defects of membrane attack complex.

>>

>> These functional tests are fundamental, due to the fact that in a

>> qualitative defect of any component of complement (without quantitative

>> defect), there will be a reduction of the value of the screening test,

>> without reduction of the quantitation of any component by any immunochemical

>> method (nephelometry, turbidimetry etc.).

>>

>> Usually complement deficiencies present clinical manifestations later in

>> life (usually autoimmunity in classical pathway activation components - C1,

>> C4, C2) and infections by encapsulated bacteria - mainly Neisserial

>> infections - with alternate pathway or membrane attack complex component

>> deficiencies.

>>

>> Therefore it is important to test for other possible complement defects

>> and follow-up these patients closely to detect any possible clinical and

>> immunological manifestation as early as possible.

>>

>> Best regards,

>>

>> Dewton

>>

>>

>> Citando Ashish Kumar <Ashish.Kumar at cchmc.org>:

>>

>>  Dear Friends,

>>>

>>> I recently saw a set of twin girls who were born at 32 weeks with

>>> twin-twin transfusion syndrome; the smaller of the two has needed a couple

>>> hospitalizations with URIs due to hypoxia. She has chronic rhinorrhea, a

>>> history of wheezing that responds to bronchodilator therapy. Someone checked

>>> her ch50 and it was <10; recheck showed the same. Her twin was then checked

>>> and hers too was <10. Their complement levels are all normal, except I don't

>>> have results on C2. They are 18 months old, have normal immune globulins,

>>> lymphocyte numbers and no serious infections. The smaller twin hasn't needed

>>> hospitalization since March, even though she has had a couple URIs since

>>> then - probably because of the season, growth and better asthma control. So,

>>> they were sent to me for consult because of the low ch50. Since the testing

>>> is sensitive to sample handling, I thought to repeat it and it is still low.

>>> I cannot reconcile the history of no serious infections with low ch50 but

>>> normal complement levels. Is this just a testing aberration? Any

>>> suggestions/ideas?

>>>

>>> Thanks!

>>> Ashish Kumar

>>>

>>> Ashish Kumar, MD, PhD

>>> Assistant Professor

>>> Cincinnati Children's Hospital Medical Center

>>> Cincinnati, OH

>>>

>>>

>>>

>>

>> <dmvascon.vcf>

>>

>

>

>

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