ABSTRACT
In Egypt schistosomiasis is prevalent among farmers who are occupationally exposed to the heavily infested water. Many complications are present among these patients, However, it is not uncommon to find cases without evidence of any complication of the disease although they all live under the same environmental conditions; many explanation have been postulated to explain these differences such as : heaviness, repitition and chronicity of infestation. However, a genetic susceptibility cannot be excluded. The aim of this work was to study the pattern of the major histocompatibility system in patients with various clinical presenrations due to Schistosoma haematobium infestation and its complications. The study included 91 unrelated patients with urinary schistosomiasis as well as 100 unrelated Egyptian control.Patients were classified into: Group I, 22 cases with simple urinary schistosomiasis. Group II, 22 cases with benign Bilharzial lesions of the bladder. Group III, 26 cases with malignant lesions in Bilharzial bladder. Group IV, 21 cases with hepato-splenic Bilharziasis. All groups of patients and controls were tissue typed using the microdroplet lymphocytotoxicity technique was done. Some human leucocytic antigen [HLA] had positive associations [HLA-B5, BW[4] AND BW[6]] and the other had negative associations [HLA-A9] with Schistosoma haematobium infestation.The incidence of HLA-B5 antigen was found to be significantly increased among cases of group I, II and III, while HLA-B5, B8, BW4 and BW6 antigens were found to be significantly increased in cases of group IV when each group was compared with the controls. Those possessing such antigens were considered a high risk people and should be given more care if they develop Schistosoma haematobium infestation