Systematic review of the putative role of herpesviruses in pulmonary fibrosis in horses and humans

Abstract

SummaryBackgroundEquine multinodular pulmonary fibrosis (EMPF) and human idiopathic pulmonary fibrosis (IPF) have been compared due to their pathological similarities, poorly understood pathogenesis, poor response to therapy and high fatality rate. IPF lacks an adequate animal model for experimental investigation.ObjectivesAssess EMPF as a putative candidate to investigate the clinical importance of gammaherpesviruses (γ‐HVs) and their role in lung fibrosis, aetiological potential or involvement as cofactors for disease occurrence.Study designQuantitative systematic review.MethodsDatabases were searched, following a PRISMA protocol to identify relevant publications based on predetermined criteria. The articles were examined through a data extraction form designed for this review; bias, evidence and overall strength of the articles were assessed. Statistical analysis was performed on the extracted data to prove repeatability, quantify evidence and determine the significance of studies that did not include statistics.ResultsSixteen relevant publications were identified, and gaps and patterns were recognised. Virus detection within the pulmonary parenchyma and a close association within alveolar epithelial cells highlighted herpesvirus involvement in pulmonary fibrosis in both species.Main limitationsA limited number of articles matched the inclusion criteria, and raw data and the statistical analyses details were incomplete; the authors’ background in veterinary medicine may have resulted in inclusion bias.ConclusionsThis systematic review demonstrates that more research on both EMPF and IPF is required, with a methodical approach to characterise the relationship between γ‐HVs and lung cells. Similarities in the pathogenesis and clinical manifestations of EMPF and IPF support the use of EMPF as a model to study IPF and better understand the putative role that γ‐HVs, and that genetic and epigenetic factors might play in lung fibrosis. Such research could improve our approach to therapy of pulmonary fibrosis in both species.