Noncoding RNAs in diagnosis and prognosis of graft‐versus‐host disease (GVHD)

Allogeneic hematopoietic stem cell transplantation (allo‐HSCT) is a functional therapy for a plethora of hematologic malignancies and immune disorders. Graft‐versus‐host disease (GVHD), on the other hand, is one of the major complications ahead of a successful HSCT, contributing to transplant‐associated morbidity and mortality. Notably, little is known about the underlying mechanism of this event; therefore, exploring precise biomarkers and uncovering the molecular pathogenesis of GVHD is valuable for early diagnosis and treatment optimization. Thanks to the advances in sequencing techniques, the noncoding sequences of the human genome—formerly considered "junk"—are now identified as functional molecules. Noncoding RNAs (ncRNA) control cellular responses by regulating gene expression, and previous studies have shown that these tiny molecules, especially microRNAs (miRNAs), can affect allogeneic T cell responses in both animal models and clinical experiments. The present study gives an overview of the functions of various miRNAs in regulating T cell responses in GVHD. We also provide an outlook on miRNAs and long noncoding RNAs (lncRNAs) potential role in GVHD with the hope of providing a future research direction for expanding their application as the sensitive and noninvasive diagnostic or prognostic biomarkers and also the promising therapeutic targets for improving outcomes after allogeneic HSCT.