Lymphocyte expression of CD95 at rest and in response to acute exercise in healthy children and adolescents.

CD95 is essential in regulating the immune system, and its reduced expression has been associated with anthracycline resistance in some childhood leukemias. We determined whether an acute bout of exercise would influence the mixed lymphocyte expression of CD95 in healthy children and adolescents. Fifty healthy pediatric subjects (female n=25) cycled for 60 min @ 70% V O(2max). Blood was collected before, during, and after exercise to determine CD95 expression on T (CD3(+)CD19(-)) and B (CD3(-)CD19(+)) cells using flow cytometry. At rest, the percentage of CD95(hi) T cells was 29% higher in girls versus boys (p<0.001). The percentage of CD95(hi) T cells and the median fluorescence intensity (MFI) of CD95(hi) were higher during recovery versus rest (p<0.0001). The percentage of CD95(lo) T cells was lower during recovery versus rest, whereas the MFI of CD95(lo) was higher during exercise versus rest. The CD95(hi) T cell count increased during exercise, but only in 14-yr-old girls, whereas CD95(lo) T cell counts increased similarly in all groups. CD95(+) B cells were relatively unresponsive to exercise. We conclude that lymphocyte expression of CD95 is influenced by acute exercise in healthy children and adolescents. Exercise-induced alterations in CD95 expression may have clinical implications for some pediatric conditions.