Stool calprotectin monitoring after small intestine transplantation

Small intestine transplantation is the only life-saving therapy available for patients with intestinal failure and life-threatening complications of parenteral nutrition, but it is still plagued by high levels of early acute rejection. The ability to diagnose rejection noninvasively, ideally before pathologic manifestations, would be a major advance in the care of intestinal transplant patients.

We measured calprotectin levels in 732 stool samples collected, analyzed over from 72 patients having undergone 74 total transplants, and correlated them with clinical indications, ostomy output, and pathologic findings.

We found that overall patients with rejection have higher mean levels of stool calprotectin than those without, but because of significant interpatient variability, defining an effective general "cutoff" for the test is difficult. Each patient, in effect, has to act as their own control. Patients experiencing rejection episodes have greater fluctuations in calprotectin levels than those without, suggesting increased "reactivity" within the graft. Our most frequent clinical indicator for biopsy, an increase in ostomy output, had no real relationship to the discovery of rejection.

Although more frequent prospective sampling could perhaps demonstrate an advantage in early indication of rejection, based on these data, routine stool calprotectin monitoring is not strongly supported.