[Immune system characteristics in acute pneumonia]. 
In 76 patients with acute pneumonia the absolute and relative numbers of T- and B-lymphocytes and their functional activity were determined on the basis of the data on the immunoglobulin level and lymphocyte blast-transformation with phytohemagglutinine.  The character of the immune response of the patients was found to depend on the activity of the inflammatory process, its spread and the features of the clinical course of the disease.  The most pronounced changes in the immune system of the patients (a sharp decrease in the number and function of T- and B-lymphocytes) were observed in croupous pneumonia and in the prolonged course of local pneumonia, as well as in cases of considerable lesion of the pulmonary tissue (3-6 and more segments).