Treatment of refractoriness to platelet transfusion by protein A column therapy

Ten thrombocytopenic patients (platelets < 10–24 × 10(9)/L) who were refractory to platelet transfusion were investigated for their responsiveness to staphylococcal protein A column therapy. Nine patients had previously been treated with steroids, intravenous immune globulin, and/or other forms of immunosuppressive therapy without improvement in their transfusion response. All patients were receiving multiple platelet transfusions without achieving 1‐hour corrected count increments (CCIs) > or = 7500. Eight patients had antibodies that reacted with platelets and were directed against HLA class I antigens, ABO antigens, and/or platelet‐specific alloantigens. Plasma (500–2000 mL) from each patient was passed over a protein A silica gel column and then returned to the patient. Patients received from 1 to 14 treatments. A positive response to protein A therapy was defined as at least a doubling of the pretreatment platelet count and/or two successive 10‐ to 120‐minute posttransfusion CCIs > or = 7500. Following plasma treatments, 6 of 10 patients responded with daily platelet counts that averaged 48 ±/− 11 × 10(9) per L as compared with counts of 16 ±/− 7 × 10(9) per L (p < 0.0005) before treatment. Posttransfusion CCI values determined in four of these patients averaged 2480 ±/− 810 and 10,010 ±/− 3540 (p < 0.005) before and after treatment, respectively. In contrast, among the four unresponsive patients, platelet counts averaged 10 ±/− 9 and 13 ±/− 10 × 10(9) per L (p = NS), respectively, while posttransfusion CCIs were 700 ±/− 1410 and 1520 ±/− 2460 (p = NS), respectively. while osttransfusion CCls were 700 2 1410 and 1520 2 2460 (p = NS), respectively. These findings suggest that, in certain patients who are refractory to platelet trans‐ fusion because of platelet‐reactive antibodies, protein A column treatments may be an effective means of increasing platelet counts and responsiveness to platelet trans‐ fusions.