Lymphocytic colitis (LC) can be mistakenly diagnosed as irritable bowel syndrome (IBS). In a previous study on IBS, some patients showed extremely high colonic chromogranin A cell density. Further examination of these patients showed that they suffered from LC.
To investigate whether chromogranin A cell density is increased in LC patients and to examine the possibility of using this increase as a marker for the diagnosis of LC.
Fifty-seven patients diagnosed with LC and 54 controls were included in the study. Biopsies from the right and left colon were obtained from both patients and controls, which were immunostained using the Avidin–biotin-complex method for chromogranin A, and cell density was quantified.
In both the right and left colon of patients with LC, the density of chromogranin A was significantly higher than in controls. This increase in chromogranin A cells occurs whether the number of these cells is expressed as number/mm2 epithelium or as number/field. Chromogranin A cell density for the right and left colon expressed as number of cells/mm2 epithelium or as cell number/field showed a high sensitivity and specificity as a diagnostic marker for LC.
Chromogranin A is a common marker for endocrine cells, and the present finding suggests that colonic hormones are involved in the pathophysiology of LC. The chromogranin cell density seems to be a good diagnostic marker with high sensitivity and specificity in both the right and left colon, thus sigmoidoscopy can be used in the diagnosis of LC using with this marker.
Keywords: Diagnosis, Chromogranin A, Colon, Computer image analysis, Immunohistochemistry, Lymphocytic colitis