Grading Histopathology Features of Graft-versus-host Disease in Animal Models; A Systematic Review

Graft-versus-host disease (GvHD), a frequent and severe complication following allogeneic hematopoietic stem cell transplantation, presents substantial morbidity and mortality risks. The crucial role of histopathological examination in diagnosing and grading GvHD, particularly within animal models, is pivotal for elucidating disease mechanisms and assessing emerging therapies. This systematic review aims to critically evaluate the various grading systems for GvHD in animal models, emphasizing histopathological characteristics. In this endeavor, we meticulously examined original research articles sourced from PubMed, Scopus, Web of Science, and Google Scholar. Our findings reveal a diverse array of grading systems, each differing in the tissues examined, criteria evaluated, severity scoring scales, and the granularity of the information provided. Predominantly, skin, liver, and gut tissues are assessed, though some systems also incorporate lung and thymus evaluations. This review will delve into the alignment between clinical and histological grading in animal models of GvHD, also casting light on prospective advancements and the impact of technological progress. In conclusion, our analysis underscores the imperative need for uniform criteria and consistent application of grading systems. Such standardization is essential to foster comparability across studies and enhance the translation of preclinical discoveries into clinical applications.