Abstract Background Anti-integrin αvβ6 IgG autoantibodies have emerged as a promising serologic biomarker for ulcerative colitis (UC); however, their role in distinguishing UC from acute diarrhoeal (AD) illnesses remains underexplored. This study evaluated the diagnostic performance of anti-integrin αvβ6 IgG autoantibodies in differentiating UC from AD. Methods In this cross-sectional study, 112 adults were enrolled: 44 with UC, 44 with AD, and 24 healthy controls (HC). Serum anti-integrin αvβ6 IgG levels were measured by ELISA (MBL, Japan). A diagnostic cut-off was defined as the mean + 3 SD of HC values. Diagnostic indices, including sensitivity, specificity, predictive values, and accuracy, were calculated. Correlations with clinical activity and inflammatory markers were assessed in UC. Results Mean age was 27.5 ± 13.4 years in UC, 34.5 ± 8.7 in AD, and 39.4 ± 10.7 in HC, with male predominance in UC (68.2%). At a threshold of 0.48 IU/mL, anti-αvβ6 positivity was observed in 42/44 (95.4%) UC and 14/44 (31.8%) AD, yielding 95.4% sensitivity, 68.2% specificity, 75.0% PPV, 93.7% NPV, and 81.8% accuracy. Among AD with bloody diarrhea, specificity increased to 75.0% and accuracy to 91.1%. Seropositivity persisted across active (100%) and remission (92%) UC stages. Antibody levels correlated with CRP (r = 0.31, p = 0.043). Conclusion Serum anti-αvβ6 IgG demonstrates high sensitivity and specificity for distinguishing UC from acute diarrhoeal illness. Its stable expression across both remission and active UC state and strong NPV suggest potential utility as an adjunctive diagnostic tool in selected patients. Multicenter validation with pathogen-specific characterization is warranted. Conflict of interest: Goyal, Manjeet: None Kumar, Mukesh: I don’t have conflict of interest. Narang, Himanshu: None Verma, Mahak: No conflict of interest Mubbunu, Malambo: No conflict of interest Garg, Rohit: No conflict of interest Mahajan, Mridul: None Sachdeva, Karan: No conflict of interest Shastri, Siddhant: I declare no conflict of interest. Makharia, Govind K: No conflict of interest Kedia, Saurabh: No conflict of interest Prof. Dr. Ahuja, Vineet: No conflict of interest
Goyal et al. (Thu,) studied this question.