Endoscopic features of the intestinal mucosa in patients with ulcerative colitis depending on the level of IgG4

Abstract

Background. Ulcerative colitis has long-term severe local and systemic consequences, often recurs which determines the urgency of developing new diagnostic markers for screening this pathology. The purpose of the study: to investigate the endoscopic picture of the colonic mucosa in ulcerative colitis depending on the content of IgG4 in the blood serum and the presence of tissue IgG4. Materials and methods. Seventy-five patients with ulcerative colitis were examined, they were treated at the department of intestinal diseases of the State Institution “Institute of Gastroenterology of the National Academy of Medical Sciences of Ukraine”. Of them, 42 were women and 33 were men aged 18 to 69 years, the average age was (40.1±1.4) years. Most patients (n=54) had a moderate ulcerative colitis, in 14 patients, the course was severe and 7 people had a mild ulcerative colitis. Endoscopic studies of the colon were performed according to generally accepted methods using the video colonoscope Olympus EVIS EXERA III (Japan). The level of IgG4 in blood serum was evaluated in all patients using the Stat Fax 303 Plus immunoassay analyzer (USA) according to the instructions for the test kit of reagents manufactured by the Xema company (Ukraine). The control group consisted of 15 practically healthy people. The presence of IgG4-positive plasma cells was determined by the immunohistochemical method, using monoclonal rabbit anti-human IgG4 (Abcam, USA). Results. An increase in the level of IgG4 over 1.2 g/l was detected in 45 patients. In general, in patients with ulcerative colitis the concentration of IgG4 in blood serum was 2 times higher (p<0.05) compared to the control group: 1.50 (0.55; 2.25) g/l versus 0.65 (0.45; 0.80) g/l. Patients with ulcerative colitis had an increase in the level of both serum and tissue IgG4 accompanied by an increase in the frequency of detecting the endoscopic signs of the disease; therefore, endoscopic activity of degree 3 is detected 2 times (p<0.05) and 2.9 times (p<0.001) more often than in patients with normal concentration of IgG4. Conclusions. Correlations found between the levels of serum and tissue IgG4, as well as with the severity of endoscopic manifestations of ulcerative colitis substantiate the feasibility of assessing the level of IgG4 in the blood as a non-invasive marker for predicting the course of this disease.