Estudo retrospectivo de infecção por citomegalovírus através das técnicas automatizadas de imuno-histoquímica e hibridização in situ em biópsias de enxerto renal de pacientes transplantados do Hospital Universitário Pedro Ernesto no período de 2019 a 2023

Abstract

Human cytomegalovirus (HCMV) is a DNA virus belonging to the beta-herpesvirus family that replicates in the nucleus of the infected cell. After primary infection, HCMV can remain latent throughout the host's lifetime and reactivate in immunosuppressed individuals, such as transplant recipients, due to reduced immune defenses. In renal transplant recipients, HCMV reactivation may contribute to allograft rejection and compromise both patient and graft survival. Diagnosis can be performed using methods such as pp65 antigenemia, polymerase chain reaction (PCR), and, in cases of suspected invasive disease, renal biopsies, in which viral presence can be evidenced by intranuclear and cytoplasmic viral inclusions or by direct detection of antigens via immunohistochemistry (IHC) or viral nucleic acids through chromogenic in situ hybridization (CISH) technique. These histological techniques are highly specific and allow determination of the direct involvement of HCMV in the examined tissue. This study aimed to evaluate the presence of HCMV in renal biopsies of transplant patients using automated IHC and CISH techniques, to compare the two methods, and to standardize and implement these methodologies in the Pathology Laboratory at the Rio de Janeiro State University (UERJ). This retrospective study, in which 33 formalin-fixed, paraffin-embedded (FFPE) kidney graft biopsy samples collected between 2019 and 2023 from the Pedro Ernesto University Hospital (HUPE) were analyzed. Additionally, 10 samples from different tissues were used to validate the protocols of both techniques. Both methodologies demonstrated satisfactory sensitivity and specificity, and the protocols were successfully validated. Among the renal biopsy samples, 18 were positive by CISH, and only one sample was positive by both techniques. The results indicate that CISH was more sensitive than IHC in detecting HCMV-infected cells, especially in cases with a low number of infected cells or non-classical morphological patterns. Based on these findings, it was possible to implement and standardize both automated techniques for diagnostic and research use, benefiting renal transplant patients and other patient groups with clinical and/or histological suspicion of HCMV infection.