ESPN 53rd Annual Meeting

ESPN 2021


 
Lower Pneumococcal Serotype-specific B-cellular Response in Children with Idiopathic Nephrotic Syndrome (INS) under Cyclosporin-A (CsA)
VARVARA ASKITI 1 KONSTANTINA KITSOU 2 ARGYROULA ZAMPETOGLOU 1 MARIANNA TZANOUDAKI 3 EMMANOUIL LIATSIS 3 GKIKAS MAGIORKINIS 4 ANDROMACHI MITSIONI 1 VANA SPOULOU 2

1- PEDIATRIC NEPHROLOGY DEPARTMENT, "P. AND A. KYRIAKOU" CHILDRENS HOSPITAL, ATHENS, GREECE.
2- IMMUNOBIOLOGY AND VACCINOLOGY RESEARCH LABORATORY, FIRST DEPARTMENT OF PEADIATRICS, “AGHIA SOPHIA” CHILDREN’S HOSPITAL, SCHOOL OF MEDICINE, NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENS
3- DEPARTMENT OF IMMUNOLOGY & HISTOCOMPATIBILITY, SPECIFIC REFERENCE CENTRE FOR PRIMARY IMMUNODEFICIENCIES-PAEDIATRIC IMMUNOLOGY, "AGHIA SOPHIA" CHILDRENS HOSPITAL
4- DEPARTMENT OF HYGIENE, EPIDEMIOLOGY AND MEDICAL STATISTICS, MEDICAL SCHOOL, NATIONAL AND KAPODISTRIAN UNIVERSITY OF ATHENS
 
Abstract:

Objective: Children with INS under immunosuppression often demonstrate lower vaccine-derived protection. We evaluated the effect of a booster dose of 13-valent Pneumococcal Conjugate Vaccine (PCV13) on antigen-specific B-cellular immunity against Pneumococcal Serotypes, PS1 and PS9V, in children under CsA and corticosteroids.

Methods: Blood was collected from INS patients, aged 6-10 years under CsA (n=4), corticosteroids (n=5) and from age-matched healthy controls (n=6), prior and one-month post PCV13. Peripheral Mononuclear Cells (PBMCs) were isolated. For the identification of PS1- and PS9V-specific B-cells, PBMCs we stained using chemically-biotinylated-polysaccharides bound to anti-biotin-coated beads and PE-conjugated anti-biotin antibodies along with CD10-APC-AlexaFluor-750, CD20-ECD, CD19-PC7. PS-specific B-cell counts were calculated by multiplying the CD19+CD20+CD10-PS+ event frequencies derived from cytometry and a total B-cell count measurement. Cytometric data were analyzed using Kaluza 2.1. Mann-Whitney U-test and Wilcoxon-rank test were performed.

Results: At baseline, patients under CsA demonstrated lower antigen-specific B-cell counts than controls for both serotypes (p=0.019 for PS1 and p=0.0105 for PS9V), while no significant differences were found between children under corticosteroids and controls. After PCV13, patients under CsA demonstrated lower antigen-specific B-cell counts compared to controls for both serotypes (p=0.0105 for PS1 and p=0.0105 for PS9V), while no significant differences were found between children under corticosteroids and controls. Comparing pre- and post-PCV13 PS-specific B-cell counts in each group, no significant increase was found in children under CsA, while significant increases were detected in controls (2-fold increase for PS1 and 2.57-fold increase for PS9V, both p=0.0277) and patients under corticosteroids (1.82-fold increase for PS1 and 2.32-fold increase for PS9V, both p=0.043).

 

Conclusions: These results indicate a negative effect of CsA on PS-specific B-cell responses to PCV13. This Flow-Cytometry method assisted the detection of these differences, despite the small sample. It remains to determine the potential correlation of these differences with the achievement of protective antibody titers.