The increased incidence of reactions to platelets compared with fresh frozen plasma suggests that a platelet-related factor may be responsible for many of the reactions. The possible role of platelet microparticles or activated platelet membranes, which carry a negative charge similar to ionic radiocontrast media, the major cause of iatrogenic anaphylactic reactions in the hospital, is explored.

Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare but well-established fatal complication of blood transfusion. It can occur in immunocompetent patients when they receive transfusions from human leukocyte antigen-haploidentical donors who have lymphocytes with antigens that are not recognized as foreign by the host, but that recognize the host's tissues as foreign. It is generally viewed as a T-cell-mediated process. Graft-induced immune hemolysis or passenger lymphocyte syndrome is a well-described complication of marrow or solid organ transplantation in which immune competent donor B cells produce alloantibodies to recipient red blood cell (RBC) antigens and cause hemolysis of the recipient's RBCs. It is generally considered as a separate process from GVHD, although it could be considered a type of GVHD. Despite the theoretical possibility of both a B-cell and T-cell component to TA-GVHD, detection of a humoral antibody in cases of acute TA-GVHD has not been described. We describe the clinical course and laboratory evaluation of a group A combat trauma patient who was acutely resuscitated with group O fresh whole blood and RBCs and group AB fresh-frozen plasma who experienced the onset of the clinical symptoms of TA-GVHD as well as the onset of hemolysis due to donor-derived anti-A in his plasma 11 days after transfusion.

Renal medullary carcinoma is an aggressive neoplasm of the renal pelvis arising in patients with a history of sickle‐cell trait. The authors report a case of renal medullary carcinoma with positive urinary cytology. Due to the location of the tumor in the renal pelvis and the loosely cohesive nature of poorly differentiated neoplasms, the presence of renal medullary carcinoma in a urinary cytology specimen is not surprising. The cytologic characteristics as well as the ultrastructural features are described. Diagn. Cytopathol. 1998;18:276–279. Published 1998 Wiley‐Liss, Inc.