FRI0507 The prevalence of latent tuberculosis infection in indian patients of takayasu arteritis

Background Studies have shown a correlation between Tuberculosis (TB) and Takayasu arteritis (TA). Some even postulate that infection with TB is required for the initiation of aortoarteritis. Hence, this project was undertaken to find an association of TB and TA by studying the prevalence of Latent Tuberculosis Infection (LTBI) in Indian TA patients. Objectives To study the prevalence of LTBI in Indian TA patients and see whether LTBI is more in these patients as compared to the historical cohort (40% in Indian population). Methods This was a cross sectional observational study. All consecutive patients with TA (satisfying the ACR 1990 criteria) were included prospectively from a period of May 2016 to December 2017. Their clinical, laboratory and radiological data were collected after obtaining informed consent. Patients were divided into groups based on the angiographic classification. LTBI was assessed by the Mantoux test and Quantiferon TB Gold test. Mantoux test (MT) was done with 5TU and results were read after 48–72 hours. An induration more than 10 mm was considered positive. Quantiferon TB Gold assay (QTB) was done by ELISA technique and (patient minus control) value >0.35 IU/ml was considered positive. A positive result of MT and /or QTB was considered positive for LTBI. Chest X-ray was included to access evidence of past or active TB lesions. Active infection was defined as clinical and microbiological and /or radiological evidence of TB. The study was approved by the Ethics committee of Medanta hospital. Results Out of 66 consecutive TA patients, 46 patients had tests available for LTBI and these were included in the analysis. The mean age of the cohort was 34.9 years with a median disease duration of 24 months. Males consisted of 11 patients whereas females formed the majority i.e. 35 patients (M: F= 1: 3.1). Angiographic Type V (54.3%) was the commonest in the cohort followed by Type IIB (17.3%), Type IV, I, IIA and III (15.2%, 8.6%, 2.1% and 2.1% respectively). LTBI positivity was present in 32.6% of the cohort; with 5 patients (10.8%) having both tests positive. 6 patients were MT positive without being QTB positive and 4 patients were only QTB positive. Eight patients had history of Tuberculosis out of which 1 was diagnosed with TB and TA simultaneously. Four patients were diagnosed as TA during the course of Anti tubercular treatment (ATT) between 4 to 6 months, whereas the rest were diagnosed after ATT completion. The mean duration of Anti tubercular treatment was 8 months. Koch’s contact was seen in 7 patients. Conclusions The prevalence of LTBI in Indian Takayasu patients was 32.6%, which was not higher than the population prevalence (40% in the historical cohort). However, a larger cohort and further association studies are needed for the relationship between TA and Tuberculosis. Disclosure of Interest None declared