Cytomegalovirus Antibody (CMV) can precipitate and exacerbate gastrointestinal mucosal injury. Studies suggest that IHC performed on infected tissue with monoclonal antibodies directed against the CMV immediate early antigen is considered by most to be the current gold standard for diagnosis. This antibody is a mixture of two monoclonal antibodies that reacts with immediate early and early protein antigens in tissues infected with cytomegalovirus. Studies indicate that this antibody does not react with herpes virus or human papilloma virus (HPV). In the later stage of infection, a cytoplasmic reaction may be observed.