[Recto-colic graft-versus-host disease (GVH). Diagnostic and prognostic criteria in a cohort of patients from Amiens university hospital].

Introduction: Recto-colic graft-versus-host disease (GVHD) is a frequent and serious complication of hematopoietic stem cell allogeneic transplantation, which is sometimes difficult to diagnose. The aim of our study was to identify histological diagnostic and prognostic criteria for recto-colic GVH.

Material and method: Patients allografted at Amiens university hospital from 2012 to 2017 were retrieved. Those who had a recto-colic biopsy were included and divided into two groups (final diagnosis of GVH and non-GVH), then biopsies were reviewed by 2 pathologists.

Results: One hundred and nineteen patients were included. Sixty-seven were allocated to the GVH group and 52 to the non-GVH group. In the GVH group, we observed a significantly greater number of apoptotic bodies (AB) on standard HES staining and with the anti-Caspase 3 immunohistochemistry, cryptolytic AB abscesses, atrophy, regenerative glands and glands lined with eosinophilic cells (P<0.001). Anti-Caspase 3 immunohistochemistry revealed more AB than standard HES staining (P<0.005). But to differentiate GVH cases from non-GVH cases, we obtained a threshold value of 3.5 AB per 10 contiguous crypts on standard HE staining and with the anti-Caspase 3 immunohistochemistry. From 4 AB per 10 contiguous crypts, on HES staining and anti-Caspase 3 immunostaining, the diagnosis of GVH became consistent. No non-GVH case had more than 6 AB per 10 contiguous crypts. GVH patients with more than 8 AB per 10 contiguous crypts had a worse prognosis (P<0.001).

Conclusion: We confirm the value of AB and their counting in the diagnosis of GVH, with a diagnostic threshold of 4 AB and a prognostic threshold of 8 AB. Glands lined with eosinophilic cells could be an additional diagnostic criterion in favor of GVH to be confirmed by further studies.