B-206 Immune Cell Alterations and Cytokine Crosstalk in Steroid-Sensitive and Steroid-Resistant Pediatric Nephrotic Syndrome

Abstract

Idiopathic nephrotic syndrome (INS) is a primary glomerular disease affecting 2 to 6-year-old children. In the world, there are 10 to 50 cases for every 100,000 people. Males are impacted more at a 3:1 ratio than females. The pattern of primary nephrotic syndrome in Indian children is comparable to that of patients in the USA and Europe. The mechanism of immunological insult causing podocyte injury or podocytopathy in the disease remains elusive. Based on their responses, children are categorized as steroid-sensitive nephrotic syndrome (SSNS) or steroid-resistant nephrotic syndrome (SRNS) after 4 weeks of standard steroid therapy. Our research aimed to investigate the urine cytokines (interleukin 4, interleukin 13, and interferon gamma) and blood lymphocyte subpopulation (CD3, CD45, CD4, CD8, and CD19-positive cells) in pediatric INS cases. The primary objectives of our study were to detect the alteration of blood lymphocyte subpopulation in INS in comparison to healthy controls using flow cytometry and to estimate the urinary cytokines in relation to proteinuria to correlate the changes in urinary cytokines with the altered lymphocyte subpopulation. We also wanted to assess variations in both blood lymphocyte subpopulation and urinary cytokines in response to steroid therapy. 51 children (17 SSNS, 17 SRNS, and 17 healthy controls) were enrolled after Ethical clearance was obtained from our Institutional Ethics Committee (IEC). An informed consent from a parent and/or legal guardian is obtained for every study participant before enrolment. Children who are diagnosed with INS according to KDIGO definitions and after baseline investigations (edema, >3+ proteinuria on dipstick, Serum albumin <2.5 g/dL (<25 g/L) and Hypercholesterolemia (Serum cholesterol > 200 mg/dL) were included as cases. Blood and urine samples were collected both before and after steroid treatment. Immunophenotyping was done by flow cytometry and cytokine assays were performed by ELISA kits. In SSNS patients, only CD8 positive cells were raised at the initial visit. CD4, and CD19 positive cells were elevated in SRNS children. Post-steroids, B cells rose in both SRNS and SSNS patients, but only the former had significantly higher CD4 counts (p = 0.034) while the latter had significantly higher CD8 counts (p = 0.028). On follow up, only SRNS children had significantly higher urinary cytokines, particularly IFN-? and IL-13 (p = 0.022 and 0.046, respectively). Increased CD8+ T lymphocyte counts on the initial visit in patients with SSNS and SRNS suggest that cytotoxic T lymphocytes and cytokines derived from them are important in initiating the disease process. But the Th1 and B lymphocytes, along with their cytokines, primarily IFN-?, are essentially accountable for the emergence and complications of INS. When distinguishing cases from controls, CD3+, CD4+, and CD8+ cell counts at the first visit can be useful for diagnosis. Additionally, CD4+ and CD19+ counts are useful in anticipating steroid resistance, enabling alterations to the therapeutic intervention, and preventing the grave adverse consequences of prolonged steroid therapy. This work was partially supported by the Indian Council of Medical Research (ICMR) with grant No. 3/2/Dec-21/PG-Thesis-HRD (15).