P1125 - High Diagnostic Accuracy of Anti-Integrin αvβ6 IgG Serology in Differentiating Ulcerative Colitis From Acute Diarrheal Illnesses in Endemic Settings: A Prospective Diagnostic Accuracy Study

Manjeet Kumar Goyal, MBBS, MD, DM, DNB¹, Himanshu Narang, MBBS, MD, DM², Mukesh Singh, BSc², Mahak Verma, BSc², Rohit Garg, MBBS, MD, DM², Mridul Mahajan, MBBS, MD, DM², Malambo Mubunnnu, MBBS, MD, DM², Govind Makharia, MBBS, MD, DM², Saurabh Kedia, MBBS, MD, DM², Vineet Ahuja, MBBS, MD, DM²
1Cleveland Clinic Akron General, Akron, OH; 2All India Institute of Medical Sciences, New Delhi, Delhi, India

Introduction: Ulcerative colitis (UC) and acute infectious diarrhea (AD) frequently present with overlapping clinical features such as increased stool frequency, haematochezia, urgency, etc. complicating early diagnosis—particularly in regions where enteric infections are endemic and invasive diagnostics are not readily available. While anti-integrin αvβ6 IgG autoantibodies have shown high diagnostic utility in distinguishing UC from Crohn’s disease and healthy controls, their value in differentiating UC from AD—a frequent and clinically relevant challenge—remains unexplored.

Methods: In this prospective, single-center diagnostic accuracy study, 112 adults were enrolled: 44 with UC, 44 with AD, and 24 healthy controls (HC). Serum anti-αvβ6 IgG levels were measured using a standardized ELISA (MBL, Japan), with antibody titres quantified against a seven-point calibration curve using four-parameter logistic regression model. A diagnostic cut-off was defined as the mean + 3 SD of values in the HC cohort. Test performance was assessed using sensitivity, specificity, PPV, and NPV. Correlations with disease activity indices and inflammatory markers were evaluated.

Results: The mean age was 27.5 ± 13.4 years in UC, 34.5 ± 8.7 years in AD, and 39.4 ± 10.7 years in HC groups, with male predominance in the UC cohort (68.2%). Anti-αvβ6 seropositivity was observed in 95.4% of UC patients versus 31.8% with AD, yielding a sensitivity of 95.4% (95% CI: 84.5–99.4), specificity of 68.2% (52.4–81.4), PPV of 75.0% (65.9–82.3), NPV of 93.7% (79.2–98.3), and AUC of 0.916 (Table 1 and Figure 1). Antibody titres correlated positively with CRP (r = 0.31, p = 0.043), but not significantly with SCCAI, partial Mayo, or UCEIS. The assay maintained performance across disease phenotypes and medication use.

Discussion: Anti-αvβ6 IgG demonstrates excellent sensitivity and NPV in differentiating UC from acute diarrhea, reinforcing its potential as a non-invasive diagnostic adjunct in ambiguous presentations. To our knowledge, this is the first study evaluating its performance in a cohort where acute diarrheal syndromes are prevalent. Future multicenter studies are warranted to validate these findings and assess its role in reducing diagnostic delays and unnecessary endoscopies in high-burden regions.


Figure: Table 1: Analysis of performance of anti-integrin auto-antibody in differentiation between Ulcerative Colitis and Acute Diarrhoea


Figure: Figure 1. Receiver Operating Characteristic (ROC) Curve for anti-integrin αvβ6 IgG serology in distinguishing ulcerative colitis (UC) from acute diarrhea (AD). The area under the ROC curve (AUC) was 0.916, indicating excellent discriminatory power. The ROC curve (cyan line) plots sensitivity (true positive rate) against 1 − specificity (false positive rate) at various threshold settings. The red diagonal line represents the reference line for a non-discriminative test (AUC = 0.5).
Abbreviations:
ROC – Receiver Operating Characteristic; AUC – Area Under the Curve;UC – Ulcerative Colitis; AD – Acute Diarrhea.


Disclosures:
Manjeet Kumar Goyal indicated no relevant financial relationships.
Himanshu Narang indicated no relevant financial relationships.
Mukesh Singh indicated no relevant financial relationships.
Mahak Verma indicated no relevant financial relationships.
Rohit Garg indicated no relevant financial relationships.
Mridul Mahajan indicated no relevant financial relationships.
Malambo Mubunnnu indicated no relevant financial relationships.
Govind Makharia indicated no relevant financial relationships.
Saurabh Kedia indicated no relevant financial relationships.
Vineet Ahuja indicated no relevant financial relationships.

Manjeet Kumar Goyal, MBBS, MD, DM, DNB¹, Himanshu Narang, MBBS, MD, DM², Mukesh Singh, BSc², Mahak Verma, BSc², Rohit Garg, MBBS, MD, DM², Mridul Mahajan, MBBS, MD, DM², Malambo Mubunnnu, MBBS, MD, DM², Govind Makharia, MBBS, MD, DM², Saurabh Kedia, MBBS, MD, DM², Vineet Ahuja, MBBS, MD, DM². P1125 - High Diagnostic Accuracy of Anti-Integrin αvβ6 IgG Serology in Differentiating Ulcerative Colitis From Acute Diarrheal Illnesses in Endemic Settings: A Prospective Diagnostic Accuracy Study, ACG 2025 Annual Scientific Meeting Abstracts. Phoenix, AZ: American College of Gastroenterology.