A comprehensive clinical and morphologic examination of 160 nephrologic inpatients included titration of antibodies to respiratory viruses and to HBsAg and of streptolysin O. A correlation was detected between immunity status parameters and the presence and severity of proteinuria in the patients with chronic glomerulonephritis. Besides routine clinical and laboratory examinations, thorough serologic and virologic studies are necessary for this patient population, for such studies will help determine the trigger mechanism of the disease and thus predict the possible development of the condition.