IMMUNOLOGICAL STUDIES IN TYPHOID-FEVER .2. CELL-MEDIATED IMMUNE-RESPONSES AND LYMPHOCYTE SUB-POPULATIONS IN PATIENTS WITH TYPHOID-FEVER

Abstract

The development of the cell-mediated immune response (CMIR) to antigens prepared from Salmonella typhi was investigated in patients with typhoid fever and in normal healthy subjects. The leukocyte migration inhibition test, blast transformation of lymphocytes and active rosette-forming cells were used for detecting CMIR. Peripheral blood lymphocytes were analyzed for the numbers and proportions of B lymphocytes, T lymphocytes and their subpopulations with receptors for IgM (T.mu.) or IgG (T.gamma.) and cells with Fc receptors for IgG. These parameters were correlated with the duration and the severity of illness. The uncomplicated cases of typhoid fever had an intact CMIR as compared to the complicated cases. The ratio of T lymphocyte subpopulations was grossly imbalanced in typhoid patients; the numbers of T lymphocytes and their subpopulations were further altered in the complicated cases as compared to uncomplicated cases. A depressed state of CMIR in complicated patients with typhoid fever was demonstrated. CMIR may thus emerge as the cardinal point for recovery in typhoid fever rather than the specific antibodies. Imbalance within the subsets of T lymphocytes may be responsible for the depressed state of CMIR in complicated cases of typhoid fever.