Role of HLA typing and chimerism analysis in post‐liver transplantation GVHD in pediatrics: A systematic review

Background GVHD is a well‐documented complication after liver transplantation. GVHD occurs when donor immune cells mount a destructive immune response against host cells. The rarity of the GVHD complication and the nonspecific presentation of symptoms and histopathological features provide a diagnostic challenge. Therefore, diagnosis and initiation of treatment are often delayed. Aim In this systematic review, we assessed relevant literature to better understand the utilization of HLA typing and chimerism analysis in liver transplantation. We mainly focused on their importance in diagnosing GVHD incidence after liver transplantation. Results A total of 18 articles reported 21 cases of GVHD after liver transplantation in pediatrics. Generally, there is a consensus on the advantage of HLA typing and chimerism analysis in confirming the diagnosis of GVHD after liver transplantation. However, there is an inconsistency in the timing and the application of the accurate HLA typing and chimerism analysis. Conclusion Further studies are required to assess the incidence of GVHD post‐LT and to determine the impact of HLA typing and chimerism analysis in assessing the risk, early determination of GVHD incidence, and improving outcomes. This systematic review highlights the gap in the field of liver transplantation and calls for revisiting the guidelines to consider HLA typing and chimerism analysis in predicting GVHD before transplantation and diagnosing GVHD incidence after liver transplantation.