[CIS PIDD] [cis-pidd] B-cell memory subsets & Selective IgG deficiency

[CIS-PIDD]

Dear colleagues,

I would greatly appreciate advice regarding immune findings in 2 adult patients.

Patient 1 is a 55 year-old lady referred to me with a 4 year history of recurrent URTI’s (bronchitis, sinusitis) and pneumonia in December 2016. Blood tests revealed selective reduction in serum IgG of 5.32 g/L (7-16), normal IgM & IgA. Protective specific IgG against Diphtheria & tetanus, Haemophilus Influenza B – 2mg/L ( >1.5 ), Strep Pneumonia 46.1 mg/L ( >35 ). Unfortunately, we don’t have access to individual Strep pneumonia serotypes. Secondary causes of Protein loss and malignancy were excluded. Immune subsets revealed raised CD3+ (5101) with raised CD4 & CD8 but normal CD4/8 ratio, normal NK and B-cells absolute counts. B-cells - 9.65%, Total memory B-cells (19+27+) 35%, Naïve B-cells (19+D+M+ 27-) 62.8%, IgM memory (19+D+M+27+) 23 %. Class switched (19+27+M-D-) & Non-class switched (19+27+D+M-) are both 0%. In some ways this B-cell profile is a mirror image of the CVID patients Joe Church recently posted with normal switched memory B cells and poor vaccine responses.
The reduced serum IgG could be due to intermittent steroid use over the past 2 years. Any support for Ig replacement (may be difficult to fund because of intact vaccine responses, but absent switched memory subset may help)?
Any one favor AB prophylaxis at this stage and just monitor?

2nd patient is a 70 year-old lady admitted with bilateral pneumonia, on a background of recurrent sinusitis and basal bronchiectasis. Serum IgG was mildly depressed at 6.81 g/L  with  normal range  serum IgA, IgM & IgE. Immunophenotyping revealed  normal CD3/CD4/CD8 and NK subsets.Baseline vaccination status  showed sub-protective values of specific IgG  against tetanus toxoid and Haemophilus B influenza,  but  markedly elevated  specific IgG  against strep pneumonia of 1297 (she was given Pneumovax 23 in July 2016). B-cell phenotyping  disclosed normal circulating B cells  of 21.7%,  normal total memory population of 39%, and normal class-switched B-cells  of 14.3%,  and low naive population of B-cells at 1.16%.
What is the implication of low naïve B-cells for this patient? Does it imply a restricted antibody repertoire,  resulting in  susceptibility if exposed new infectious organisms, despite normal range switched memory B-cells?

I would greatly value comments and suggestions.

Thanks & Regards,

Stan

Stan Ress
Emeritus Associate Professor of Medicine, UCT
Specialist physician & Clinical Immunologist,
UCT Private Academic hospital, Anzio Road, Observatory,
Cape Town, 7925 South Africa
TEL:INTERN<file://///localhost/tel/INTERN>. + 2721-4421966 or 4421816 FAX:   "    + 2721-(0)865173095
Cell: 0833115482
email: stan.ress at uct.ac.za<mailto:stan.ress at uct.ac.za>
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