Fecal Calprotectin In Allogeneic Stem Cell Trasplantation as Surrogate Marker of Gastrointestinal Graft Versus Host Disease

Abstract 2327 Background: Calprotectin is a major cytosolic protein of neutrophils that have showed to be a sensitive marker of intestinal inflammation. The aim of our study has been to evaluate fecal calprotectin (FC) as a diagnosis tool in patients with acute gastrointestinal graft versus host disease (GI GVHD). Methods: Since March 2009, patients with suspicion of acute GI GVHD were consecutively included. Patients were tested for FC (reference range: 0–30 mg/kg) before starting treatment. Infections by Clostridium difficile, cytomegalovirus, fecal bacteria and intestinal parasites were also excluded. Colonoscopy was performed in all patients and biopsy samples were taken for histopathological examination. Results: To date, eleven patients have been included. The median age was 48.2 (r: 21–67). Indications for transplantation included acute myeloid leukemia (6 patients), myelodysplastic syndrome (2 patients), acute lymphoid leukemia, severe aplastic anemia and refractory follicular lymphoma (1 patient, respectively). Ten patients received myeloablative conditioning and one received reduced intensity conditioning regimen. Five patients were histologically diagnosed with acute GI GVHD. The median for FC in this group was 510.5 (r: 107.4–629). The median of FC in patients without GI GVHD was 117 (r: 13.9–205). Patients with GI GVHD had higher values of FC than patients without GI GVHD (p:≤0,009) For a cut-off point value of 205, sensitivity for the test was 83.3% (IC 61.3–100%), specificity was 100%, positive predictive value was 100%, and negative predictive value was 83.3% (IC 61.3–100%). In 3 patients who were diagnosed with cytomegalovirus enteritis and had no criteria for GI GVHD, the FC values were 15.4, 105, and 100.7. In a patient with Candida spp. infection FC was 13.9. The FC was higher in patients with grade IV GI GVHD, with median of 590 (r: 502–629). Conclusion: FC appears to be a promising non-invasive biomarker of acute GI GVHD. If these findings are confirmed, it may provide a useful non-invasive test for the diagnosis of GI GVHD in patients following allogeneic transplantation. Disclosures: No relevant conflicts of interest to declare.