[The role of intraepithelial lymphocytes in pathogenesis of small intestinal bacterial overgrowth syndrome]

Small intestinal bacterial overgrowth (SIBO) is a frequent cause of chronic abdominal complaints. So far, a lot information has been gathered on its pathogenesis but are still doubts that raise question why its causes chronic diarrhea in some and constipation in other patients.

Aim: The aim of the study was to assess the number of endothelial lymphocytes (IELs) in the duodenal and ileum mucosa in patients with SIBO with dominant diarrhea (SIBO-D) and dominant constipation (SIBO-C).

Materials and methods: The study was performed in 30 healthy patients (group I) and 40 patients with SIBO and diarrhoea (group II), and in 4o patients with constipation (group III). To diagnose SIBO the lactulose hydrogen breath test (LHBT) was performed. To determine the number of intraepithelial lymphocytes in duodenal and jejunal mucosa the histological assessment was performed using haematoxylin-eosin staining. Moreover, immunochistochemical method was used to assess the number of enterochromatoffin cells (EC, chromogranin A - LK-2H10) in these some parts of the gut.

Results: The results of LHBT were similar in group II and III - 75,6±18,1 ppm and 66,9±16,2 ppm(p>0,05). The number of IELs in duodenal mucosa in controls was 14,6±4,1/100 EN, in group II - 28,3±6,8/100 EN (p<0.01), and in group III - 23,0±9,9/100 EN (p<0,05), and similar differences were in jejunal mucosa. The number of EC in both parts of the gut was higher in SIBO compared to controls. Furthermore, in patients with SIBO-D the number of IELs in duodenum, as well as in jejunum, was positively correlated with the number of EC cells ( p<0,05, p=0,056, respectively).

Conclusions: In patients with SIBO, particularly with SIBO-D, increased number of IELs I EC cells may be a cause of diverse abdominal symptoms.