[CIS-PAGID] B-cell subset question

[Zachary D. Jacobs, MD]

Hello all,


I have been seeing a 52 year-old woman who was started on IVIG about 18
months ago by a now retired immunologist.  She had been having recurrent
sinusitis and had frequent courses of antibiotics but she had no imaging
performed during this time, did not have history of sinus surgery and did
not have much in the way of lower respiratory tract infections.   Her
quantitative immunoglobulins were normal, except that IgM was consistently
high in the 450 mg/dl range.  SPEP was normal.  Vaccine testing at the time
showed suboptimal response to PPV-23 with pre-immunization specific
antibody panel showing 5 of 12 serotypes > 1.3 ug/ml and post-immunization
it rose to 7/12 serotypes with protective levels.  Therefore, she was
started on IVIG by him and she has clinically improved with fewer
infections.


I have been evaluating her and would like to trial her off of IVIG.  What I
have been doing of late is obtaining B-cell subsets on patients, and if
their memory B-cell counts and frequencies are normal I encourage them to
go off IVIG to see how it goes.  For this patient, the frequencies of the
memory B-cells were normal, as were the counts of the switched and
unswitched memory B-cells, but the count of the IgM-only memory B-cell was
elevated at 16 cells/mcl (0-12), and her total IgM(+) B-cell count was
elevated at 395 cells/mcl (37-327) with 87% of CD19 cells being IgM(+).  I
thought this was interesting given her historically high IgM counts.


Does anyone have experience in dealing with this particular immunophenotype
and how she would fair off IgG replacement?  Should any further work-up be
undertaken?


As an aside and while I’m here writing, this same retired immunologist had
several patients on IVIG with at times soft indications.  Since I have been
doing B-cell subsets on these patients I have found several that have
normal memory B-cell counts (switched and unswitched) but had low numbers
of plasmablasts (CD38+ IgM -/+).  These patients often have a history of
chronic bronchitis or sinusitis with a mildly low IgG in the mid-400 to
mid-500 mg/dl range, normal IgA and IgM, and mild to moderately impaired
specific antibody responses to PPV-23.  What is the clinical significance
of low plasmablasts potentially causing hypogammaglobulinemia, especially
in regards to infectious complications and need for IgG replacement?


Thanks as always,


Zach

-- 
Zachary D. Jacobs, M.D.

The Center for Allergy & Immunology

Saint Luke’s Physician Partners
Medical Plaza II
4330 Wornall, Suite 40
Kansas City, MO 64111

Ph: 816.531.0930
Fax: 816.753.2671

 CONFIDENTIALITY NOTICE. This e-mail and attachments (if any) may contain
information that is confidential, proprietary, privileged or otherwise
prohibited by law from disclosure or re-disclosure. This information is
intended solely for the individual(s) or entity(ies) to whom this e-mail or
attachments are addressed. If you have received this e-mail in error, you
are prohibited from using, copying, saving or disclosing this information
to anyone else. Please destroy the message and any attachments immediately
and notify the sender by return e-mail. Thank you.

P *Please consider the environment before printing this message.*
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://seven.pairlist.net/mailman/private/pagid/attachments/20120508/da9b87a3/attachment.html>