DIAGNOSTIC VALUE OF INTERLEUKIN-6 AND D-DIMER IN INFLAMMATORY BOWEL DISEASES
Authors: Lutsyk А. P. , Shorikova D. V. 
Published: July 2021

The article deals with the diagnostic value of changes in the content of interleukin-6 and D-dimer in patients with inflammatory bowel diseases (IBD) - Ulcerative Colitis (UC) and Crohn Disease (CD).
Materials and methods: We have studied 34 patients with UC and 18 people with CD with continuously recurrent course. There are also analysed data of 15 patients with UC and 15 patients with CD in period of the remission. The control group included 30 healthy volunteers. Clinical, endoscopic examination, an immunoassay determination of the content of interleukin-6 (IL-6) and D-dimer, was carried out. CD activity was assessed using the Chron’s disease activity index. The localization of CD was established according to the Montreal classification. The clinical activity of the disease in patients with UC was determined using the classification according to Truelove-Witts. The value of the index consisted of the sum of points for each indicator, which allowed determining the activity of the inflammatory process.
Statistical processing was performed using STATISTICA 10.0 (StatSoft. Inc., USA), at p<0.05, the discrepancies between the obtained data were considered statistically significant.
Research results. According to the obtained data, mild activity was found in 7 patients with UC (20.6%) and 4 - with CD (22.3%), moderate severity - in 17 (50.0%) and 8 (44.4%) patients, severe - in 10 (29.4%) and 6 (33.3%) patients. In the remission stage, 15 patients with UC and 15 patients with CD were examined. According to the Montreal classification, lesions of the upper gastrointestinal tract (L4) were observed in 4 patients with CD (22.2%), terminal ileitis (L1) occurred in 10 patients (55.6%), 4 patients were diagnosed with ileocolitis (L3) - 22.2%.
It has been established that patients with an active course of UC and CD had a higher level of proinflammatory markers and thrombosis markers (D-dimer and IL-6) compared with inactive course and control group (p<0.05). The D-dimer content in UC was 690±315 pg/l. It is confirmed the increase of the content of this marker in 2.55 times compared to control group and in 1.43 times than inactive course of the disease respectively. The level of IL-6 at active in course of UC was 3.36±1.78 pg/ml, increasing in 2.07 times against control and in 1.72 times compared with group of remission.
In the active course of CD, the level of D-dimer reached 720±267 pg/ml, increasing in 2.67 times in relation to control and in 1.60 times with respect to patients under remission. The content of IL-6 in the active course of CD reached 4.07±2.17 pg/ml, increasing in 2.85 times in comparison to healthy individuals and in 2.83 times relatively patients with remission.
While using the ROC-analysis, the most sensitive value as a “cut point” for the diagnosis of the active process in the course of IBD can be considered the content of the D-dimer in an amount of more than 650 pg/l. The calculated AUC in ROC-analysis for the IL-6 content was 73.7%±6.14% (61.7 - 85.7, p<0.001), indicating the prognostic value of the model. The values of the IL-6 content of more than 2.80 pg/ml are diagnostically significant to predict the active process in IBD.