ESPN 54th Annual Meeting

ESPN 2022


 
Deciphering the immunological mechanisms underlying pediatric Idiopathic Nephrotic Syndrome
GIULIA CRICRI 1 LINDA BELLUCCI 2 STEFANIA BRUNO 3 FEDERICO CAICCI 4 STEFANO TUROLO 5 WILLIAM MORELLO 5 GIOVANNI MONTINI 5 FEDERICA COLLINO 1

1- DEPARTMENT OF CLINICAL SCIENCES AND COMMUNITY HEALTH, UNIVERSITY OF MILANO, MILAN.
2- LABORATORY OF TRANSLATIONAL RESEARCH IN PAEDIATRIC NEPHRO-UROLOGY, FONDAZIONE CA GRANDA IRCCS OSPEDALE MAGGIORE POLICLINICO, MILAN
3- DEPARTMENT OF MEDICAL SCIENCES, UNIVERSITY OF TURIN, TURIN
4- DEPARTMENT OF BIOMEDICAL SCIENCES, UNIVERSITY OF PADOVA, PADUA.
5- PEDIATRIC NEPHROLOGY, DIALYSIS AND TRANSPLANT UNIT, FONDAZIONE CA GRANDA IRCCS OSPEDALE MAGGIORE POLICLINICO, MILAN.
 
Introduction:

Idiopathic Nephrotic Syndrome (NS) is the most common glomerular disease in children, with immune-related pathogenesis. Corticosteroids are the first-line treatment, but patients not responsive may progress to end-stage renal disease. The identification of a biomarker signature to predict treatment efficacy will be useful to redefine INS patients’ classification based on individual immune profiles, rather than on response to treatment.

Material and methods:

PBMCs, sera and urines were obtained from thirty INS children (steroid-sensitive and resistant) at different time-points (onset, remission, relapse) and seven young healthy donors (HS). The dynamics of the changes in the immune repertoire were detected by flow cytometry. Extracellular vesicles (EVs) concentration and morphology were analysed by Nanoparticle Tracking Analysis and Transmission Electron Microscopy. Molecular analyses (lipidomic and proteomics) were conducted on Size Exclusion Chromatography isolated EVs.

Results:

 No significant differences were observed in the total CD19+ B lymphocytes in INS children with active proteinuria in respect to the HS, whereas their levels were significantly enhanced compared with remission state. INS patients show higher levels of naïve and switched memory B cells compared to HS (p <0.05), that were maintained elevated during remission. Focused on the steroid-sensitive INS group, transitional B cells decreased and plasmablasts and plasma cells increased in these patients compared to the same group in remission (p <0.05). In the T cell compartment, we detected a significant increase of Th2 and Th17/Th1 ratio in proteinuric INS in respect to HS, and higher levels of Foxp3+ T reg during remission (p <0.05). NTA analysis revealed no differences in EV concentration. Biofluid INS-EVs expressed tetraspanins with a heterogeneous distribution among the patients’ subgroups; the highest expression was observed during remission. Serum INS-EVs showed an increase in lymphocytic markers, that were already detected in EVs at the disease onset. Urine INS-EVs were enriched of adhesion, epithelial and leucocyte molecules, and their number positively correlated with proteinuria levels.

Conclusions:

 Changes in the biofluid EV profile embody the bloodstream immune dysfunctions, supporting their possible participation in INS pathophysiology.