The relationship of lymphocytes in blood and in lymph to sleep/wake states in sheep.

Based on evidence of a role for immune-associated cytokines in sleep induction, we investigated the possibility that lymphocyte distribution between blood and lymphatics could be altered as a function of sleep/wakefulness. Blood and lymph sample were obtained from 5 sheep during periods of slow-wave sleep and wake. Blood and lymph lymphocytes were phenotyped using monoclonal antibodies against CD4, CD8, gd T-cell receptors and a surface marker on ovine B cells. Lymph flow rates and efferent lymph cell output were measured. Lymph flow and prescapular efferent lymphocyte output were reduced during sleep compared to wakefulness (p<0.0005). There were no differences in lymphocyte subsets in the blood and in the lymph during sleep/wake brain states. These data indicate that migration of cells in the peripheral lymphatic system is altered during sleep compared to wakefulness.