Association of some HLA-DRB1 antigens with Echinococcus granulosus specific humoral immune response.

An ELISA system using crude camel hydatid fluid antigen was used to detect specific IgG and IgG1 in sera of 35 cystic echinococcosis (CE) patients in whom the distribution of class II HLA-DR3 and HLA-DR11 was determined. The recorded sensitivities were 88.6 % and 94.35 % for IgG and IgG1 respectively. In patients with high humoral immune response a statistically highly significant increased frequency of HLA-DR3 (P<0.01) was recorded for IgG with high relative risk value (RR=3.2) and reasonable etiologic fraction (EF=0.3), while HLA-DR11 recorded P<0.05, RR=2.6, & EF=0.2. For IgG1 both antigens showed significant increased frequency (P<0.05), RR (2.95 & 2.79 respectively), EF (0.28 & 0.23 respectively). HLA-DR3 was highly significantly associated with complicated cases (P<0.01, RR=4.36, EF=0.4) in whom the mean antibody units for both IgG and IgG1 were significantly raised (P<0.05). It is advisable to rely on IgG1 for the diagnosis of CE and to consider the genetic disposition of the patient as an important criterion in the outcome of infection.