Citrulline and albumin as biomarkers for gastrointestinal mucositis in recipients of hematopoietic SCT

Gastrointestinal (GI) mucositis is a common side effect of intense chemotherapy to prepare patients for hematopoietic SCT. Measuring intestinal damage objectively remains difficult, and clinicians often rely on albumin levels as an indicator of GI mucositis, but citrulline might be a more specific marker, which has in the past been shown to correlate with clinical signs of GI mucositis. We evaluated the courses of albumin and citrulline following different conditioning regimens for SCT and studied their relatedness to the subsequent inflammatory response using C-reactive protein. Patterns of albumin and citrulline differed significantly between myeloablative and non-myeloablative conditioning regimens. After myeloablative regimens, decreasing citrulline levels preceded the occurrence of inflammation unlike albumin levels, which decreased thereafter. Albumin levels were greatly influenced by inflammation, confirming it to be a 'negative acute-phase protein', whereas citrulline levels were not. Citrulline appeared to be a better biomarker of GI mucositis than albumin. Measuring citrulline might prove useful in clinical decision making, in identifying GI mucositis, and it would also be of interest to see how it compares with other biomarkers in the setting of acute GI GVHD.