Evaluation of calprotectin levels in intestinal content as predictor of small bowel transplant rejection.

GRUZ, FERNANDO; ERREA AGUSTINA; MAURIÑO EDUARDO; RUMBO CAROLINA; CABANNE, ANA; RUMBO MARTIN; GONDOLESI GABRIEL

Los Angeles, CA, USA

Congreso; VI World Congress on Intestinal Transplantation; 2007

Early detection of rejection is a critical issue in the follow up of intestinal transplant patients. Since there is a lack of biochemical markers of rejection, surveillance of the graft status is usually performed by histologycal observations on biopsies taken following a protocol of serial endoscopic controls. Calprotectin is a major cytoplasmatic protein of neutrophils and due to its compact folding is stable even in extracellular aggressive compartments such as the intestinal lumen. Calprotectin determination in feces has been successfully applied for the detection of active intestinal bowel disease. The aim of the present work was to evaluate the use of calprotectin determination for monitoring small bowel rejection. We measured calprotectin levels on intestinal content recovered at the time of endoscopies, using a commercial ELISA on 85 samples obtained along the follow-up of 9 patients transplanted in our center during 2006. Along the follow-up period some patients presented episodes of graft rejection determined by histologycal observation (mild in 3 cases, severe in 2 cases), as well as gastrointestinal and systemic infections episodes. Using the histology as diagnostic criteria for rejection, the cut-off level of the calprotectin determination was calculated retrospectively by ROC analysis. The best assay parameters using a cut off value of 65 ug of calprotectin/g of intestinal content were 68% sensitivity and 55% specificity. Increase in calprotectin levels were correlated with the presence of gastrointestinal infection, intestinal lesions other than rejection, resulting in high number of false positive results. Few false negative results were observed, that were coincident with the recovery of rejection episodes under the effects of immunosuppressive treatment adjustment. Calprotectin determination could be useful for monitoring gastrointestinal abnormalities in the follow up of intestinal transplant patients, however since many factors may contribute to its rise, it should be used in combination with other tests that may provide an accurate diagnostic.