HLA class II antigens positively and negatively associated with hepatosplenic schistosomiasis in a Chinese population

To identify possible associations between host genetic factors and the onse t of liver fibrosis following Schistosoma japonicum infection, the major hi stocompatibility class II alleles of 84 individuals living on an island (Ji shan) endemic for schistosomiasis japonica in the Poyang Lake Region of Sou thern China were determined. Forty patients exhibiting advanced schistosomi asis, characterised by extensive liver fibrosis, and 44 age and sex-matched control subjects were assessed for the class II haplotypes HLA-DRBI and HL A-DQB1. Two HLA-DRB1 alleles, HLA-DRB1*0901 (P = 0.012) and *1302 (P = 0.03 9), and two HLA-DQB1 alleles, HLA-DQB1*0303 (P = 0.012) and *0609 (P = 0.03 7), were found to be significantly associated with susceptibility to fibros is. These associated DRB1 and DQB1 alleles are in very strong linkage diseq uilibrium, with DRB1*0901-DQB1*0303 and DRB1*1302-DQB1*0609 found as: commo n haplotypes in this population. In contrast, the alleles HLA-DRB1*1501 (P = 0.025) and HLA-DQB 1*0601 (P = 0.022) were found to be associated with re sistance to hepatosplenic disease. Moreover, the alleles DQB1*0303 and DRB1 *0901 did not increase susceptibility in the presence of DQB1*0601, indicat ing that DQB1*0601 is dominant over DQB1*0303 and DRB1*0901. The study has thus identified both positive and negative associations between HLA class I I alleles and the risk of individuals developing moderate to severe liver f ibrosis following schistosome infection. (C) 2001 Australian Society for Pa rasitology Inc. Published by Elsevier Science Ltd. All rights reserved.