Colucci M, et al. - In this study performed on pediatric patients with idiopathic nephrotic syndrome (INS, n=153), researchers focused on the link between an atypical presence of IgM on the surface of T cells (T-cell IgM) and the response to steroid therapy in various phases of the disease. At disease start, T-cell IgM median levels were significantly raised and predicted relapse risk in 47 patients. Neither the amount of total circulating IgM, nor concomitant acute infections or oral immunosuppression had any impact on T-cell IgM in vivo. Findings revealed a correlation of increased T-cell IgM with reduced IgM sialylation, which impacted T-cell response to steroid inhibition and T-cell production of podocyte-damaging factors. Overall, in a subset of steroid-sensitive pediatric patients with INS, a predisposition to a poor response to steroid therapy, since disease onset, may be seen due to the atypical presence of IgM on the surface of T cells.