Crossmatch-compatible platelets improve corrected count increments in patients who are refractory to randomly selected platelets.

Abstract

HLA-matched platelets and crossmatch-compatible platelets are used to support thrombocytopenic patients who are refractory to randomly selected platelets. Data supporting the effectiveness of crossmatch-compatible platelets are limited, being essentially restricted to the subset of refractory patients previously shown to be alloimmunized. The authors' hospital does not test for alloimmunization. To determine the effectiveness of crossmatch-compatible platelets in an unselected group of refractory patients, the use of such platelets for all patients who are refractory to random-donor platelets was reviewed. All patients who received crossmatch-compatible platelets between January 1991 and May 1994 were retrospectively reviewed. All study patients were refractory to random-donor platelets, having two consecutive corrected count increments (CCIs) of < 10,000. A solid-phase red cell adherence method was used for platelet crossmatching, and CCI was used to monitor the effectiveness of each platelet transfusion. A total of 475 crossmatch-compatible platelet components were administered to 66 evaluable patients who were refractory to random-donor platelets. A significant improvement was found in the mean CCI when crossmatch-compatible platelets were compared with randomly selected platelets (p < 0.0001): an increase of 8000 +/- 6100 (mean +/- SD). In 59 percent (39/ 66) of the patients, the mean CCI improved to at least 7,500 and in 41 percent (27/66) to at least 10,000. If the 10 patients for whom crossmatch-compatible platelets were not identified are included, the mean CCI in 51 percent (37/76) of the refractory patients improved to at least 7,500; in 36 percent (27/76), it improved to at least 10,000. The effectiveness of crossmatch-compatible platelets did not decline with continued use. Crossmatch-compatible platelet components significantly improve the mean CCI for approximately one-half of patients who are refractory to random-donor platelets, even when the patients are not preselected for having alloimmunization to explain their refractory state.