[Post transfusion purpura--a serious underdiagnosed delayed post-transfusion event].

UNLABELLED: Post-transfusion purpura (PTP), a delayed post-transfusion event, is underdiagnosed, not only in Poland. Thrombocytopenia results from the destruction of patients' and transfused platelets by platelet specific antibodies (anti-HPA). The incidence of PTP is not estabilished.

THE AIM: Analysis of 10 cases with PTP diagnosed in Poland during last 25 years.

MATERIAL AND METHODS: 9 women and 1 man with normal platelet count who developed thrombocytopenia with diathesis haemorrhagica after transfusion of red cells or/and platelets. Platelet specific antibodies (anti-HPA) were examined by the platelet immunofluorescence test and by the monoclonal immobilization of platelet antibodies (MAIPA) assay; leucocyte antibodies by standard lymophocytotoxicity test (LCT).

RESULTS: In all 10 patients the PTP was diagnosed because: 1) thrombocytopenia with diathesis haemorrhagia occured 3-10 days after the transfusion (in 5 cases blood was transfused during the operation), 2) in all the patients anti-HPA were detected (in 9- anti-HPA-1a, in 1 case anti-HPA-3a), 3) a primary HPA alloimmunization was very probable. A recovery of platelets count occured in 6 patients within 8-34 days after corticosteroids and/or IVIG, however, therapeutic effect of them was difficult to assess due to a great probability of spontaneous remission up to 1 month. Four patients died due to their basic disease although the impact of the PTP cannot be excluded.

CONCLUSION: The diagnosis of PTP was possible because of the detection of anti-HPA antibodies in patients who developed thrombocytopoenia after blood transfusion.