An improved immunocytochemical method for the detection of human cytomegalovirus antigens in peripheral blood leucocytes

Summary A recently described immunoperoxidase method for the detection of nuclear human cytomegalovirus (HCMV) immediate early antigen (IEA) directly on periphiral blood leucocytes suffers from the drawback that the antigen is vulnerable to endogenous peroxidase inactivation procedures. To solve this problem a procedure is developed in which endogenous peroxidase is inactivated after binding and immobilization of the primary antibody with 4% formaldehyde. In combination with this procedure, three types of inactivation were investigated: glucose/glucose oxidase, hydrochloric acid and methanol/H₂O₂. Of these three, the first gives optimal results, especially in combination with methanol/acetic acid (20/1 v/v) as the primary fixative. This produre results in preparations which allow for a more objective evaluation and enable automated examination using bright field microscopy.As a second improvement we developed a simple adherence method in order to diminish the risk of infection for the laboratory staff during processing of unknown blood samples. The protocol described shows great clinical potentual for the diagnosis of HCMV infections.Supported in part by the Nier Stichting Nederland (grants No's: C-83404 and C-86606) and Het Praeventiefonds, The Netherlands (grant No: 28-1346)