Cell mediated immunity at high altitude

Cell mediated immunity (CMI) was assessed by determining total and differential leucocyte and absolute lymphocyte counts, T and B-rosettes, PHA-blast transformation of lymphocytes, lymphocyte migration index (LMI), and DNCB response in 66 sea-level residents, 45 temporary residents, and 24 natives at high altitude (3,692 m). An accentuated CMI, indicated by increase in PHA-blasts, increased lymphocyte migration index, and intense DNCB response, was present, despite a mild decrease in total leucocytes in temporary residents and in lymphocytes in natives at high altitude. While T-rosettes did not show any change in numbers, B-rosettes were increased in temporary residents, and natives at high altitude. A qualitative change had, therefore, occurred in lymphocytes at high altitude. CMI is equally augmented in temporary residents and natives at high altitude and prevails at a higher plane than at sea-level. Augmentation of CMI at high altitude, therefore, could be used as a therapeutic measure.