Inhibition of interferon, cytokine, and lymphocyte proliferative responsesin elite swimmers with altitude exposure

To determine the immunologic consequences of athletic training at altitude, blood samples were taken at rest from 10 swimmers and 8 control nontrainin g but altitude-exposed members of the 1996 Australian Olympic Swimming Team , near the start and completion of a 21-day training camp at 2102 m, Blood leukocyte numbers dropped in both groups (p < 0,05), with the decrease grea ter in the swimmers (-38% swimmers, -3% controls). Concanavalin A (ConA)-in duced blastogenesis decreased in both groups (p < 0,01), but the drop was g reater in the control group (-32% swimmers, -56% controls, p < 0,05), Lipop olysaccharide (LPS)-induced blastogenesis more than doubled in both groups (281% swimmers, 249% controls, p < 0,01), Increases in mitogen-induced inte rleukin-1 beta (IL-1 beta), IL-4, and interferon-gamma (IFN-gamma) producti on and a decrease in IL-2 levels were observed in both groups after altitud e exposure (all p < 0,05), The percentage of cells expressing HLA-DR fell ( -33% swimmers, -20% controls, p < 0,01), whereas those expressing CD-4 expr ession increased (16% swimmers only, p < 0,01), Although training at medium -level altitude alters some immunologic parameters, the training-induced ch anges may be secondary to those induced by altitude alone.