Diagnosis of celiac disease

Area of Science:

• Gastroenterology and Immunology
• Genetic Epidemiology
• Diagnostic Medicine

Background:

• Celiac disease, an immune-mediated enteropathy triggered by gluten in genetically susceptible individuals, is increasingly reported globally, including India.
• Historically, diagnosis relied on small intestinal mucosal biopsy and gluten withdrawal, but evolving epidemiology necessitates refined diagnostic approaches.
• The true prevalence in India remains underestimated due to missed diagnoses, highlighting the need for improved awareness and diagnostic tools.

Framework:

• Celiac disease histopathology ranges from increased intraepithelial lymphocytes to classical villous atrophy, presenting a heterogeneous spectrum.
• The Indian subcontinent exhibits diverse histological presentations, potentially leading to missed diagnoses if solely based on severe changes or if mild/moderate changes lack serological correlation.
• Serological markers, including antiendomysial (Anti EMA) and anti-tissue transglutaminase antibodies (anti-tTGA), offer high sensitivity and specificity (>95%) for diagnosis.

Implementation:

• Anti-tTGA assays are preferred for large-scale screening over operator-dependent Anti EMA tests, though variations in antigen sources and assay techniques can impact accuracy.
• Genetic predisposition is strongly linked to HLA-DQ2 or HLA-DQ8. Over 97% of North Indian celiac patients possess the HLA-DQ2 heterodimer, indicating a significant genetic risk.
• HLA-DQ2 typing serves as a valuable tool for excluding celiac disease in equivocal cases, boasting a negative predictive value exceeding 95%.

Implications:

• The protean clinical manifestations and heterogeneous histology underscore the importance of a standardized diagnostic algorithm for celiac disease.
• Accurate and timely diagnosis is crucial for effective management and preventing long-term complications associated with untreated celiac disease.
• Enhanced diagnostic strategies incorporating serology and genetic markers are vital for improving celiac disease detection rates, particularly in diverse populations like India.