A rapid immunocytochemical assay for CMV detection in peripheral blood of organ-transplanted patients in clinical practice

Abstract

This study describes clinical experience with a rapid method for diagnosis of cytomegalovirus infection in organ-transplanted patients, based on the detection of CMV-specific antigens in peripheral polymorphonuclear cells with a mixture of monoclonal antibodies. This CMV-pp65 assay was formerly called the "CMV immediate early antigen assay." A group of 180 organ-transplanted patients were examined with this assay; 75 of them could be observed from the date of transplantation. These 75 patients consisted of two groups: 59 kidney transplant patients receiving no CMV hyperimmunoglobulin prophylaxis (group I), 13 heart-transplanted patients, and 3 liver transplanted patients receiving prophylaxis (group II). Group III consisted of 105 patients who had been transplanted ca. 2 years before starting this study. In group I, 26 (44%) were CMV-pp65-positive (13 primary and 13 secondary infections). Fifteen of these 26 (58%) positive patients showed clinical symptoms of CMV infection. Eleven of these 15 (73%) were primary infections. Symptomatic patients had significantly more CMV-pp65-positive cells than asymptomatic patients; 12 patients showed a high number of positive cells and 11 of them developed severe CMV illness. Thirty-three patients were CMV-pp-65-negative (22 CMV IgG-sero-positive, 11 CMV IgG-seronegative). None of them had symptoms of CMV infection. In all patients of group I there were 36 periods of graft dysfunction in which CMV infection had to be differentiated from transplant rejection. In 10 out of 36 there was a CMV-pp65-positive test result and subsequent seroconversion. Treatment of viral infection resulted in improvement of clinical problems. In the remaining 26 episodes no CMV-pp65-positive cells were detected: in 17 cases graft dysfunction was caused by rejection, in 9 cases by other complications. In group II, 13 of 16 patients (81%) were positive in the CMV-pp65 assay (6 primary infections, 7 secondary infections). However, none of them showed clinical signs of CMV infection, regardless of the number of positive cells. No CMV-related graft dysfunction was observed. In group III, CMV infections did not play an important role. The experiences described suggest that this test is a valuable tool in early CMV diagnosis and in differentiating CMV-dependent graft dysfunction from other graft dysfunctions. It allows prompt therapeutic intervention.