Tuberculosis screening in adult patients with inborn errors of immunity: a single-center cohort study.

Background: Data on tuberculosis, a leading cause of infectious disease mortality, in patients with inborn errors of immunity (IEI) are limited. Objective: This study aimed to evaluate the burden of tuberculosis and the diagnostic utility of the tuberculin skin test (TST) in patients with IEI and to propose a tuberculosis screening strategy. Methods: Evaluation comprised a comprehensive exposure history, symptom assessment, TST (which was repeated after 1-4 weeks if the initial result was 0-4 mm), and chest imaging including radiography and computed tomography where available. Patients underwent standard clinical assessment for tuberculosis, followed by appropriate treatment and follow-up. Results: Among 117 patients with IEI [median age = 35 years, interquartile range (IQR) = 26-45.5 years], antibody deficiencies were the most common subgroup (82.1%). All patients had previously received a Bacillus Calmette-Guérin (BCG) vaccination. Of the 105 patients who underwent TST, 19 had a history of tuberculosis, the majority of whom had pulmonary involvement (59.1%), and three had recurrent disease. Three patients diagnosed with pulmonary, gastrointestinal, and lymph node tuberculosis had TST values of 22, 9, and 9 mm, respectively. Two patients with TST measurements of 12 and 6 mm were diagnosed with non-tuberculous mycobacterial lung disease. The median TST was 9 mm (IQR = 1.5-14.25 mm) in patients with tuberculosis and was 4 mm (IQR = 0-10.5 mm) in those without. Conclusion: This study represents the first comprehensive evaluation of tuberculosis screening and TST assessment in patients with IEI. Pulmonary tuberculosis was the most common site of involvement. In BCG-vaccinated patients with IEI who developed tuberculosis, the TST responses remained below the conventional 15-mm threshold, highlighting the need for revised cutoff values in this population, similar to those recommended for patients with HIV.