Serum beta 2-microglobulin as a biomarker in inflammatory bowel disease

AIM: To investigate the diagnostic utility of beta 2 microglobulin(B2-M) levels and analyze this correlation with the activity of inflammatory bowel disease(IBD).METHODS: Overall, 78 IBD patients and 30 healthy controls were enrolled in the study. We examined B2-M serum levels in 43 ulcerative colitis(UC) patients, 35 with Crohn's disease(CD) and 30 control subjects, using an enzymatic method. Patients were divided into two groups according to two disease types: active and in remission. Subjects were also divided into two subgroups according to extent of the disease: left-side and pancolitis for UC and ileitis and ileocolitis for CD. All groups were compared for mean serum B2-M levels and also examined to see whether there was a correlation between serum B2-M levels and other inflammatory markers.RESULTS: The mean serum B2-M levels in the control group, UC and CD were 1.71, 2.41 and 2.24 respectively. B2-M values ≥ 1.96 mg/L had a 62% sensitivity, 76% specificity, a 79% positive predictive value, and a 58% negative predictive value for UC patients. B2-Mvalues ≥ 1.70 mg/L had 80% sensitivity, 53% specificity, 66% positive predictive value, and 69% negative predictive value for CD patients. Mean B2-M values were significantly higher in ulcerative colitis and Crohn's disease patients than in healthy controls(UC 2.41 ± 0.87 vs 1.71 ± 0.44, P = 0.002; CD 2.24 ± 1.01 vs 1.71 ± 0.44, P = 0.033). Also, mean B2-M values were significantly higher in active disease when compared to patients in remission(UC 2.66 ± 0.92 vs 1.88 ± 0.41, P = 0.004; CD 2.50 ± 1.15 vs 1.73 ± 0.31, P = 0.033). The difference between groups(UC and CD) in terms of serum B2-M levels was statistically insignificant(2.41 ± 0.87 vs 2.24 ± 1.01, P > 0.05 respectively).CONCLUSION: Serum B2-M levels may be used as an activity parameter in IBD.