Feasibility and Diagnostic Utility of Mucosal T-Cell Flow Cytometry for Intestinal Graft-Versus-Host Disease

Background and Aims: Timely diagnosis of intestinal complications after hematopoietic stem cell transplantation (HSCT), including graft-versus-host disease (GVHD), transplant-associated thrombotic microangiopathy, and cytomegalovirus infection, is essential for appropriate management. This study evaluated whether mucosal T-cell profiling from endoscopic biopsies could support the diagnosis of these post-transplant conditions.
Methods: We prospectively analyzed 58 intestinal biopsy specimens from 21 post-HSCT patients. Paired samples were obtained from the stomach and duodenum during upper endoscopy and from the ileum and large intestine during colonoscopy. Lymphocytes were isolated from each specimen and analyzed using flow cytometry. These data were integrated with those of a previously collected cohort (35 patients, 51 samples) for comparative immunophenotypic analysis across histologically defined groups.
Results: Duodenal biopsies yielded more lymphocytes than did gastric biopsies (mean ± standard deviation: 532 ± 823 vs 233 ± 392 cells; P = .070), with comparable yields between the ileum and colon. Among 41 evaluable cases, the CD56+:CD3+ ratio was significantly lower in patients with GVHD (5.5 ± 2.2%) than in those with nonspecific or no inflammation (28.4 ± 16.3%; P = .006). A cutoff value of <11% provided 85.7% sensitivity and 83.3% specificity for diagnosing GVHD (area under the curve = 0.91).
Conclusion: Mucosal T-cell profiling using endoscopic biopsies is feasible and may aid in the diagnosis of GVHD after HSCT. A decreased CD56+:CD3+ ratio is a promising marker for distinguishing GVHD from other post-transplant intestinal conditions.