Allergic reaction to psoralen‐treated platelets: Real or coincidence?

In response to Joubeh and Singh: Allergic reactions to platelets; to B or not to B?

“…In our view, these data coupled with the previous report by Joubeh et al 1 can best be explained by a small fraction of patients who have allergic reactions to the B antigen expressed on platelets or secreted in plasma. In our study, there were 890 type O patients transfused with 1798 units of B or AB products and an allergic reaction was reported in only 10 (1.1%) of these patients.…”

“…Of the four type A patients, only one (#11) had a reaction to all the B antigen positive platelets they received but this patient only received three platelet transfusions in total, so it is unknown if this is related to the B antigen. It is noteworthy that 11 of the 14 patients described here (included patient 1 and 2) and both of the subjects described by Joubeh et al 1 were male. It is unclear if this occurred by chance or not.…”

“…While likely under-powered, this does not support the possibility that psoralen treated platelets increase allergic reaction rates as suggested previously. 1 In our data set there were 10 type O patients and 4 type A patients who had allergic reactions to B or AB platelets. A summary of the platelet transfusions and allergic reactions for these 14 patients is shown in Table 2.…”

“…We read the recent letter by Joubeh and Singh discussing allergic reactions to psoralen-treated platelets (PI-Platelets) and found their data intriguing. 1 These authors describe two cases of O+ male patients developing allergic reactions after psoralen-treated platelet transfusions, and they wonder whether PI-Platelets may cause allergic transfusion reactions. However, as they noted, the allergic reactions in these patients were exclusively to AB or B platelets, raising the possibility that the ABO compatibility may provide a better explanation for their results than the PI-Platelets.…”