Diagnostic power of laboratory methods for assessing ulcerative colitis severity: A prospective comparative study

Background. The epidemiology of ulcerative colitis in the Russian Federation is typified by late diagnosis and the predominance of severe complications entailing high mortality.Objectives. A comparison of the diagnostic value of laboratory methods for assessing ulcerative colitis severity.Methods. A total of 178 ulcerative colitis patients were divided into 4 cohorts by the presence and severity of attack; a control cohort included 40 healthy volunteers. Besides standard tests, a cytokine profile was determined in all patients: IL-1 IL-2, IL-4, IL-6, IL-10, TNF-α, IL-17; faecal inflammation marker concentrations — lactoferrin (LF), calprotectin (CalP), neopterin (NP); optical anisotropy (OA) of neutrophilic granulocyte nuclei; clinical activity index (CAI); Mayo scores. A single-factor analysis of variance was performed to compare the diagnostic value of laboratory tests, with a Mayo score taken as the factor reflecting ulcerative colitis attack severity. Differences were assumed statistically significant at p < 0.05. Results. The patients suffering from ulcerative colitis exhibited statistically significant Mayo score correlations with IL-6 (r = 0.598, p = 0.001), IL-17 (r = 0.587, p = 0.005), TNF-α (r = 0.701, p = 0.001), CalP (r = 0.881, p = 0.001), LF (r = 0.799, p = 0.001), NP (r = 0.791, p = 0.001) and OA (r = –0.877, p = 0.001). Faecal inflammatory biomarkers varied in the range from 73.4 (NP) to 95.3% (CalP) of total variance. Serum markers varied from 75.2 (IL-6) to 88.1% (IL-17) of total variance. As of all markers, the highest diagnostic value was observed for CalP (95.3% of total variance), while the lowest — for NP (73.4% of total variance). In the analysis of variance, the cut-off values for serum markers in predicting endoscopically active disease (>1 Mayo score) comprised: IL-6 = 10.3 pg/mL; IL-17 = 18.5 pg/mL; TNF-α = 10.9 pg/mL. The analogous values for faecal markers were: CalP = 112.0 μg/g; LF = 80.9 μg/g; NP = 92.8 μg/g. Neutrophilic granulocytes optical anisotropy comprised 94.5% of total variance, which compares with CalP by diagnostic power.Conclusion. A high diagnostic power has been demonstrated for faecal inflammatory markers (calprotectin, neopterin, lactoferrin), cytokines (IL-6, IL-17, TNF-α) and neutrophilic granulocytes optical anisotropy in detecting the attack relapse and severity.