Platelet alloimmunization in multitransfused patients with haemato-oncological disorders.
BACKGROUND
We studied the incidence of platelet alloimmunization in multitransfused patients with haemato-oncological disorders and determined the factors influencing alloimmunization. We also assessed the effect of alloimmunization on response to platelet transfusion.


METHODS
Fifty patients with haemato-oncological disorders who received multiple transfusions were included. The patients were tested for antibodies before they received any transfusion and then after 3-4 weeks of transfusion. Lymphocytotoxicity and platelet immunofluorescence suspension tests were used to detect antiplatelet antibodies. Symptomatic improvement was used to assess the response to platelet transfusions.


RESULTS
Thirty patients were positive by the lymphocytotoxicity test, giving an incidence of 60% for anti-HLA antibodies. The panel reactivity of the antibodies ranged from 3% to 100%. Nineteen patients were positive by the platelet immunofluorescence suspension test, 16 of whom were also positive by the lymphocytotoxicity test. The overall incidence of antiplatelet antibodies was 66%. The number of transfusions received and the underlying haemato-oncological disorder were not risk factors for the development of antibodies. Patients with a past history of transfusions and those with a positive obstetric history had a significantly higher incidence of antibodies. The response to transfusion therapy was poor in patients with antibodies, as 71.4% of patients with antibodies were nonresponsive compared to only 26.6% of antibody-negative patients.


CONCLUSIONS
A high percentage of multitransfused patients developed antiplatelet antibodies. Previous sensitization was an important risk factor for the development of antibodies. Patients with high panel reactivity (HLA) showed non-responsiveness to platelet transfusions. Testing for the presence of antiplatelet antibodies and provision of compatible platelets should be important components in the management of patients with platelet transfusion refractoriness.
Bajpai
Meenu
M
Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India.
Kaura
Babita
B
Marwaha
Neelam
N
Kumari
Savita
S
Sharma
R R
RR
Agnihotri
S K
SK
D000293:Adolescent; D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006680:HLA Antigens / Q000276:immunology*; D019337:Hematologic Neoplasms / Q000097:blood / Q000276:immunology* / Q000503:physiopathology; D006801:Humans; D015994:Incidence; D007518:Isoantibodies / Q000097:blood; D008297:Male; D008875:Middle Aged; D017713:Platelet Transfusion; D012307:Risk Factors
D006680:HLA Antigens; D007518:Isoantibodies