Suitability of liquid-stored donor platelets in platelet compatibility testing.

Current platelet crossmatch procedures to select compatible donors for alloimmunized thrombocytopenic patients are hampered by the lack of a convenient platelet storage method. This study examined the feasibility of using washed apheresis donor platelets stored for up to 1 year in a modified Hank's buffer solution at 4 degrees C as crossmatch reagents in an indirect IgG-enzyme immunoassay. Pooled and monospecific HLA and PlA1 antisera were used to determine the antigenic reactivity of donor platelets in relation to duration of storage. There were no significant differences between mean HLA and PlA1 antigen expression in fresh and stored platelets. HLA reactivity was detected on 12 of 13 donor platelet samples stored for 3 to 9 months and on 14 of 17 platelets stored for 12 to 14 months. PlA1 reactivity was maintained at 12 to 14 months for all 12 donor platelet samples tested. In addition, incompatibility remained in 23 of 24 paired fresh and stored platelet crossmatches using individual alloimmunized patient plasmas. These data indicate that both HLA and platelet-specific PlA1 antigen reactivity can be maintained adequately in liquid storage at 4 degrees C for up to 1 year. The availability of a convenient platelet storage method should facilitate the general application of platelet crossmatching procedures for alloimmunized patients.

Frequency of PLA1 in blacks.

Racial frequencies of platelet-specific antigens in racial groups other than whites have not been studied. The prevalence of PLA1 was determined in white and black blood donors. Two hundred forty-two of 243 blacks were PLA1-positive (99.6%), compared with 242 of 250 whites (96.8%) (p = 0.021). This black population has the highest frequency of PLA1 yet reported.

Anti-A production by a group O spleen transplanted to a group A recipient.

A group A1 diabetic received a pancreas-spleen transplant from a group 0 donor. Severe immune hemolysis due to anti-A ensued, requiring graft splenectomy. The transplanted spleen can be a potent source of blood group antibody.

Red cell and platelet-bound IgG penicillin antibodies in a patient with thrombocytopenia.

A patient was found to have a positive direct antiglobulin test and thrombocytopenia while on a moderate dose of intravenous penicillin. Serological evaluation of the patient's red cells demonstrated that the positive antiglobulin test was due to antipenicillin antibody. This antibody also was demonstrated in the patient's serum. The patient's platelets had increased quantities of IgG; an eluate from her platelets gave positive test results with platelets treated with penicillin but not normal platelets. Her serum also reacted only with penicillin-treated platelets. Multiple absorptions of her serum with red cells treated with penicillin reduced reactivity against both fresh red cells and platelets treated with penicillin. This patient demonstrated the coexistence of drug-induced immune phenomena directed against both red cells and platelets.