C4d staining is a valuable marker in identifying chronic GVHD in colonic biopsies following BMT.

摘要

C4d is an element of the complement system and is involved in the classical pathway of complement cascade activation.1 This marker has been shown to be useful in identifying antibody mediated rejection in renal transplant biopsies and cardiac transplant biopsies.2-3 It is unclear whether C4d-positive staining can be detected in internal organs with GVHD following BMT. We report three cases of chronic GVHD identified in colon biopsies in which dilated capillaries were all positively stained for C4d, 4 months-2 years following BMT (see Table 1; Figures 1 and 2). In one of the three cases, positive staining for C4d along capillaries was further identified in the internal organs (autopsy tissue). All three patients died several weeks to a few months after colonic GVHD was diagnosed in their colonic biopsies. When pathological features of chronic GVHD were subtle, positive C4d staining was very helpful in confirming chronic GVHD. In addition, detection of peri-capillary C4d expression in colonic biopsies implied concurrent antibody-mediated rejection and chronic GVHD.