Chronic pulmonary graft-versus-host disease (Pc-GVHD) is a non-infectious complication of allogeneic hematopoietic stem cell transplantation (HSCT), typically presenting >100 days post-transplantation [1]. Its pathophysiology and underlying immunological mechanisms remain incompletely understood. Recent studies have implicated an expanded population of CD8⁺ tissue-resident memory T cells (T_RM) as key contributors to disease progression. Additionally, there is evidence of upregulated gene expression and activation of pathways involved in macrophage chemotaxis and proliferation, along with dysfunction of stromal cells exhibiting both pro- and anti-fibrotic gene signatures [2,3].
