Platelet transfusion from donors mismatched for crossreactive HLA antigens

Increments in platelet counts following the transfusion of platelets mismatched for crossreactive antigens were evaluated in 67 patients with broad alloimmunization to HLA antigens. The corrected increments following 100 HLA, A-matched and B1U- or B2U-matched transfusions were compared with the increments following 307 B1X- or B2X-matched transfusions. HLA-A3 platelets were tolerated poorly by A1 and A11 recipients, as were A1 and A11 by A3 recipients, B17 and BW21 by recipients in the B7 crossreactive group, B5 by B15 and B17 recipients, and B27 by recipients in the B5 crossreactive group. B12 and BW21, and B8 and B14 platelets were not tolerated bidirectionally. Antigens associated with good increments included A28 in A2 recipients, B18 and BW16 (C match) in recipients in the B5 crossreactive group, B5 in B18 recipients, BW22 and B7 in recipients in the B7 crossreactive group. A1 and A11 were transfused successfully bidirectionally. These observations suggest that some private antigens within crossreactive groups are more immunogenic than others and support the observation of others than B17 and BW21 are not in the B5 crossreactive group.     

Suppression or enhancement of natural killing does not alter tolerance to bovine gamma globulin

NZB/NZW F1 (B/W) mice have high levels of natural killing (NK), are resistant to the induction of tolerance to bovine gamma globulin (BGG), and spontaneously develop a disease resembling systemic lupus erythematosus. In vivo administration of 89Strontium (89Sr) to B/W mice reduces NK and improves their autoimmune disease. We tested the hypothesis that the high levels of NK exert an immunoregulatory influence and are responsible for the resistance to BGG tolerance. 89Sr was administered at 4 and 8 weeks, and tolerogen was injected at 10 weeks. Despite a marked suppression of NK, 89Sr-treated B/W mice remained resistant to the induction of tolerance. NK was stimulated in weanling B/W male and female mice, and in adult A/J females, by the injection of Poly I . C one day prior to the administration of tolerogen. Poly I . C induced an acute rise in NK but did not inhibit the induction of tolerance. We conclude that natural killer cells are not involved in the regulation of immune tolerance to BGG and, they do not appear to play a role in the resistance to tolerance in adult B/W mice.