Post-transfusion purpura: a serological and immunochemical study

Area of Science:

• Immunology
• Hematology
• Transfusion Medicine

Background:

• Post-transfusion purpura (PTP) is a rare but serious complication following blood transfusions or pregnancy.
• Identifying the specific platelet alloantibodies involved is crucial for diagnosis and management.

Observation:

• The platelet suspension immunofluorescence test (PSIFT) detected platelet-specific alloantibodies in eight female PTP patients over two years.
• All patients exhibited anti-Zwa specificity and were Aw(a-) negative.
• Platelets in two acute-phase patients were coated with IgG; eluates reacted with Zwa+ platelets.

Findings:

• Patient sera reacted strongly with Zwa-positive platelets and weakly with Zwa-negative and autologous remission platelets.
• The antibodies were characterized as IgG (all patients), sometimes with IgM, predominantly IgG1 and IgG3 subclasses.
• Complement fixation by PTP antibodies was observed in four sera, but only two showed detectable complement-binding in the 51Cr-lysis technique.

Implications:

• The findings suggest Zwa-anti-Zwa complexes may contribute to PTP pathogenesis.
• Understanding antibody characteristics aids in diagnosing and potentially treating PTP.
• Further research into complement fixation mechanisms in PTP is warranted.