Effectiveness of rituximab in nephrotic syndrome treatment.

Idiopathic nephrotic syndrome (INS) is a common chronic illness characterized by massive proteinuria and hypo-albuminemia in children. Baseline treatment is 6 month-corticotherapy. In cases of steroid resistant/dependent INS several types of treatment are used, including course of methylopred-nisolone "pulses", alkylating agents, cyclosporin A, levamisole and mycophenolate mofetil. It has been suggested that children with frequently relapsing nephrotic syndrome or steroid-dependent nephrotic syndrome had a significantly longer relapse-free period if rituximab (RTX) treatment was additionally applied. We present a case of a 4.5 boy who due to steroid-sensitive, steroid-dependent nephrotic syndrome has been successfully treated with RTX. Administration of the one dose of Rituximab in the patient caused immediate decrease of CD19/CD20 positive B lymphocyte population. The depletion of B cells has been observed for the next six months. With regard to the fact that RTX treatment may affect patient's immune response, comprehensive immunodiagnostic has been conducted in a course of the Therapy.