Alloimmunization to D antigen and HLA in D-negative immunosuppressed oncology patients.

D-negative patients may be divided into responders and nonresponders when immunized with D-positive red cells (RBC). Forty-nine D-negative oncology patients who received D-positive RBCs via platelet and white cell transfusions were studied to determine if nonresponders to D were likely to form lymphocytotoxic antibody (LCA). Nine patients developed anti-D in 16 to 390 days (mean = 112) after 2.6 to 481 ml (mean = 106) of D-positive RBCs. Forty patients had no evidence of anti-D after 0.8 to 535 ml (mean = 98) of D-positive RBCs and were followed for 14 to 1275 days (mean = 192). The anti-D group had no prior D-positive RBC transfusions, and two of five women making anti-D had previous pregnancies but no record of anti-D. LCA was found in four of nine (44%) patients with anti-D and in 12 of 40 (30%) patients without anti-D (p less than 0.50). Since both D and antigens HLA are considered highly immunogenic, it is of interest that the ability to form anti-D or LCA does not correlate. In fact, more patients (16/49; 32%) made LCA than anti-D (9/49; 18%). Of the 21 alloimmunized patients, 4 made both antibodies, while 17 had selective alloimmunization. It would thus appear that alloimmunization to D and HLA are not strongly linked and may indeed be unrelated.