Induction of a subpopulation of suppressor cells by a single blood transfusion

Blood transfusion induces immunosuppression by a mechanism which is probably multifactorial and, in large part, obscure. In this study cellular immune suppression was examined in patients with end-stage renal disease (ESRD) following a single blood transfusion (BT). OKT8⁺ cells proliferated within four hours, their count increasing significantly, and reached their peak after four days. Since OKT4⁺ cells tended to decrease, the OKT4/OKT8 ratio declined significantly from the fourth day. Evidence in support of the above results is offered in studies on ability of concanavalin A reagent (ConA)-activated T cells to form autorosettes with human red blood cells (RBC); these T cells have been shown to function as suppressor effector cells. Autorosetting cells (RFC) proliferated in a similar pattern to OKT8⁺ cells. Moreover, the percentage of rise at one and two weeks of OKT8⁺ and RFC correlated directly, suggesting that the proliferating OKT8⁺ cells are in large part a subset of suppressor cells. Functional studies were performed to establish the suppressor activity of T cells before and at various times after blood transfusion. A significant increase in T cell ConA-induced suppressor activity was found one week after BT, peaking at two weeks following BT. Monocytes increased significantly from day 4 following BT, but prostaglandin E22 (PGE₂) started to rise immediately, peaking at day 4. PGE₂ might induce suppression by induction of suppressor cells or by direct suppression of interleukin-2. Both monocytes and suppressor cells respond immediately, but they probably induce suppression most effectively four days or more after BT.