Hydatid disease or cystic echinococcosis is a parasitic infection caused by the larval stage of tape worm is one of the most significant zoonosis all around the world. In addition to environmental factors, genetic constitution of hosts seems to play a crucial role in acquiring the infection and developing disease. This study was carried out to investigate the association of HLA-class class I (A, B) with hydatid disease by genotyping in Iraqi patients, as well as to provide information about genotypes that confer susceptibility or resistance to develop the disease. Thirty patients with hydatid disease their age range (16-57) years and twenty healthy controls their ages were matched with the patients were enrolled in this study. Blood was collected from patients and controls, DNA was extracted from blood samples, and then HLA-Class I genotyping was performed by polymerase chain reaction-sequence specific oligonucleotide probes (PCR-SSO). The present findings showed that HLA-A *0273 allele is significantly higher in control group (20%) than patients group (0%), (P=021). Furthermore the current study could not observe significant differences in frequencies of HLA-B alleles between patients and control groups. We concluded that HLA-A *0273 allele may might indicate resistance to disease among patients, and the lack of association between patients group and HLA alleles could reflect racial genetic variation in HLA allelic frequencies.
