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

Data on tuberculosis, a leading cause of infectious disease mortality, in patients with inborn errors of immunity (IEI) are limited.

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.

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.

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.

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.