Humoral Immune Response to SARS-CoV-2 in Children with Idiopathic Nephrotic Syndrome: A Cross-Sectional Exploratory Study

Background: Children with idiopathic nephrotic syndrome face a high risk of infections due to an abnormal antibody response. This study aims to evaluate the humoral immunity in children with nephrotic syndrome against SARS-CoV-2. Methods: This cross-sectional study assessed anti-spike SARS-CoV-2 IgG levels in children with nephrotic syndrome and compared them with those in the control group. Data on COVID-19 exposure and vaccination were collected from caregivers. Statistical analyses were performed using appropriate parametric and non-parametric tests, with a significance level set at p < 0.05. Results: Thirty-five children (10 with nephrotic syndrome and 25 controls) were enrolled. Seropositivity rates were 60% in children with nephrotic syndrome versus 32% in controls (p = 0.15). Mean antibody levels were comparable between groups (0.74 ± 0.68 vs 0.89 ± 1.24, p = 0.64), with no statistically significant differences observed in children receiving steroid therapy. Conclusion: The humoral response to COVID-19 was similar in children with idiopathic nephrotic syndrome compared to control children, suggesting that routine vaccination schedules remain appropriate in this group. These findings suggest preserved antibody responses in this population; however, due to the exploratory nature of this study, larger studies are needed before clinical recommendations can be modified. Keywords: immunology, nephrotic syndrome, pediatric nephrology, SARS-CoV-2