Evaluation of Frequency of mastocytic enterocolitis in patients with diarrhea predominant irritable bowel syndrome and assessment of their response to mast cell inhibitor therapy

Most patients with irritable bowel syndrome (IBS) do not respond to existing treatments. It seems that the pathogenesis is not fully understood. Trying to clear this condition، scientists have focused on the role of mast cells in the pathogenesis of IBS and many gastrointestinal disorders.

After taking history including demographic، clinical، familial and personal history of 57 patients with diarrhea-predominant IBS (criteria ROME III) colonoscopy done and in case of normal colonoscopy، samples of left and right colon were taken. Overall 48 samples could be retrieved. Immunohistochemical staining for mast cell tryptase was done and mast cells were counted. The prevalence of patients with mast cells > 20 / HPF was determined. The patients were divided into three categories: < 10/HPF، 10- 20 and > 20 / HPF and symptoms of three groups were compared. In addition to their traditional treatment regimen، all patients received Ranitidine and Cetrizine. Clinical responses were also compared in the three groups.

A total of 3 out of 48 patients (5. 8%) had >20 mast cells in each HPF (mastocytic enterocolitis). Distribution and severity of clinical symptoms of the patients in three groups were not significantly different. Respond to treatment with antihistamines was not significantly different in each of these groups of patients.

Mastocytic enterocolitis in our patients was not as frequent as other studies. Mast cells count was not associated with clinical symptoms.