International Journal of Exercise Science 6(3) : 250-255, 2013. With the emergence of shared facilities, the possibility of a processing delay is increased as time on instrumentation becomes less available. The purpose of this investigation was the evaluate the effect of a 24h time delay on lymphocyte subset concentration, as well as for the apoptotic marker annexin V. Fourteen healthy individuals completed an incremental treadmill test to exhaustion, and blood samples were obtained before and after exercise. The samples were labeled in duplicate with mixtures consisting of flow cytometry staining buffer, the biomarker for early-phase cell death (annexin V), and antibodies for specific lymphocyte phenotypes (CD4, CD8, and CD19). Samples were labeled for 30-min, centrifuged, and decanted, before the addition of RBC Lysis Buffer. Upon the completion of processing, the first set of samples were immediately analyzed using flow cytometry and the remaining duplicate samples were acquired 24 h later. Data were analyzed using a paired sample t-test with significance accepted at the p < 0.05 level. For blood draws obtained at rest, no differences between acquisition days were observed with regard to cell volume for any lymphocyte subfraction. However, blood samples obtained following an exhaustive exercise bout had significant decreases in CD4+ (p=0.002) and CD8+ (p= 0.021) concentration between acquisition days. Processing delays did not affect the number of apoptotic cells in any lymphocyte subset either at rest or following exercise. As the number of apoptotic cells was unaffected by processing, the reduction in cell concentration is likely due to mechanisms other than programmed cell death. It is possible that exercise makes lymphocytes more susceptible to necrosis during the post-activity period.
Kell, Holly B.; Pereira, Guilherme Borges; Tibana, Ramires Alsamir; Jarrett, Michael; Schafer, Mark A.; Prestes, Jonato; Santo, Antonio; and Navalta, James W.
"Acquisition Delays Affect Lymphocyte Subset Counts but not Markers of Exercise-induced Apoptosis,"
International Journal of Exercise Science: Vol. 6
Available at: http://digitalcommons.wku.edu/ijes/vol6/iss3/9