The role of human leukocyte antigens as predisposing and/or protective factors in patients with idiopathic thrombotic thrombocytopenic purpura.
Fifty-four adult German patients suffering from idiopathic thrombotic thrombocytopenic purpura (TTP) have been examined for HLA class II. All patients presented autoantibodies against ADAMTS13 and ADAMTS13 activity levels <5%. Blood samples have been analyzed for HLA-DRB1 and DQB1 alleles using sequence-specific primer PCR and sequence-specific oligonucleotide PCR. Reference data of German bone marrow and blood donors were obtained from www.allelefrequencies.net. The results were evaluated employing two-sided binomial tests, and p values were corrected using the Benjamini-Hochberg procedure. A significant accumulation for DQB1*02:02 (p < 0.001) and DRB1*11 (p = 0.003) was found within the patient group. Twenty percent (DQB1*02:02) or 48.1% (DRB1*11) of TTP patients were tested positive for the particular HLA antigen compared to 1.2% (DQB1*02:02) or 23.5% (DRB1*11) in the control group. A tendency for a reduced occurrence of HLA-DRB1*04 was revealed (7.4% in patients compared to 24.6% in controls). An association between the HLA antigens DQB1*02:02 and DRB1*11 and disease susceptibility for idiopathic TTP has been found. A higher risk for disease outbreak within persons carrying the mentioned alleles can be assumed. The reduced occurrence of HLA-DRB1*04 in TTP patients indicates a possible protective effect of this HLA allele in disease development.
Department of Hematology, University Medical Center, Mainz, Germany.
Marie-Luise
ML
John
Walter
W
Hitzler
Inge
I
Scharrer
D051722:ADAM Proteins / Q000172:deficiency / Q000235:genetics / Q000276:immunology; D000071120:ADAMTS13 Protein; D000328:Adult; D000483:Alleles; D004198:Disease Susceptibility; D005260:Female; D005858:Germany; D006680:HLA Antigens / Q000235:genetics*; D006683:HLA-DQ Antigens / Q000235:genetics; D059811:HLA-DRB1 Chains / Q000235:genetics; D000949:Histocompatibility Antigens Class II / Q000235:genetics*; D006801:Humans; D008297:Male; D011697:Purpura, Thrombotic Thrombocytopenic / Q000235:genetics* / Q000276:immunology / Q000503:physiopathology
D006680:HLA Antigens; D006683:HLA-DQ Antigens; D059811:HLA-DRB1 Chains; D000949:Histocompatibility Antigens Class II; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human