Serum immunoglobulin profiles and allergic history in pediatric primary nephrotic syndrome: associations with steroid sensitivity and relapse risk

Background Primary nephrotic syndrome (PNS) is a common pediatric glomerular disease with unclear pathogenesis. Immune dysregulation and allergic comorbidities are implicated, yet the associations between immunological parameters and treatment response or prognosis remain inadequately characterized. Methods In this retrospective, cross-sectional study, pre-existing clinical data and laboratory results were collected from children with newly diagnosed PNS and from healthy controls who underwent routine health examinations during the same period. Serum biochemical and immunological parameters, including immunoglobulin (IgG, IgA, IgM, IgE) and complement (C3, C4), were analyzed, and renal biopsy results were reviewed. Patients were classified by clinical phenotype, steroid response, time to remission, and relapse frequency. Non-normally distributed variables, including serum IgE, were compared using non-parametric tests. A sensitivity analysis excluding nephritic-type PNS was performed. Results Compared with healthy controls, PNS patients showed significantly lower albumin and IgG levels ( P < 0.001) and higher cholesterol, IgM, and IgE levels ( P < 0.05). The prevalence of allergic diseases was significantly higher in PNS patients than in controls ( P < 0.001). Steroid-sensitive patients had higher IgE levels and more frequent allergic history than steroid-resistant patients ( P < 0.05). Among steroid-sensitive patients, those achieving remission within one week had the highest IgE levels ( P < 0.05), and frequent relapsers exhibited significantly elevated IgE compared with non-frequent relapsers ( P < 0.05). In the sensitivity analysis restricted to simple-type PNS, frequent relapsers continued to show significantly higher IgE levels than non-frequent relapsers ( P = 0.013), whereas the differences in IgE levels and allergic history between steroid-sensitive and steroid-resistant patients did not reach statistical significance ( P = 0.207 and P = 0.922, respectively). Conclusions Pediatric PNS is characterized by distinct immunoglobulin abnormalities. Elevated serum IgE and a history of allergy are associated with steroid sensitivity and frequent relapse. These findings should be considered hypothesis-generating, and further prospective studies are warranted to validate the potential clinical utility of these parameters.