mehri ghafourian health research institute, infectious and tropical diseases research center, ahvaz jundishapur university of medical sciences, ahvaz, ir iran; department of immunology, school of medicine, ahvaz jundishapur university of medical sciences, ahvaz, ir iran abdolhussein shakunia health research institute, infectious and tropical diseases research center, ahvaz jundishapur university of medical sciences, ahvaz, ir iran; department of immunology, school of medicine, ahvaz jundishapur university of medical sciences, ahvaz, ir iran; department of immunology, school of medicine, ahvaz jundishapur university of medical sciences, ahvaz, ir iran. tel: +98-9163132602, fax: +98-6133332036 seyed mohammad alavi health research institute, infectious and tropical diseases research center, ahvaz jundishapur university of medical sciences, ahvaz, ir iran wesam kooti student research committee, immunology department, kurdistan university of medical sciences, sanandaj, ir iran ghodratollahe shakerinejad acecr-khuzestan, health education research group, ahvaz, ir iran amirarsalan serajian acecr-khuzestan, health education research group, ahvaz, ir iran