Cytokines and erythrocyte incompatibility.

The strong resemblance between the clinical manifestations of hemolytic transfusion reactions and sepsis, in which cytokine production has a central role, suggests that similar pathophysiologic mechanisms are involved. There is an expanding body of clinical and experimental evidence that cytokines, especially interleukin-1, tumor necrosis factor, interleukin-6, and interleukin-8, are principle mediators of immune responses to erythrocyte incompatibility. Recent studies have further suggested that the monocyte chemotactic and activating factor, monocyte chemoattractant protein-1, and the anti-inflammatory cytokine interleukin-1 receptor antagonist are produced in experimental models of hemolytic transfusion reactions. Differing levels and patterns of expression of these cytokines may be seen in models of intravascular hemolysis due to ABO incompatibility and extravascular hemolysis due to Rh incompatibility, which correlate with the recognized clinical differences between these two types of reactions. Furthermore, recent studies have demonstrated that several of these same cytokines are produced during the storage of platelet concentrates, which may account for some febrile reactions that are not prevented by the use of leukocyte reduction filters.