AB0446 A comparative study of quantiferon TB-2G and 3G as screening examination for latent mycobacterium tuberculosis infection in patients with rheumatoid arthritis before treatment with biologics

Background Mycobacterium Tuberculosis (TB) infection is one of the typical adverse events during the treatment with biologics, especially anti-tumour necrosis factor (TNF) agents, in patients with rheumatic disease. The screening of latent TB infection before treatment with biologics is recommended in a lot of recommendations including ACR recommendation and recommendation in European countries. Several methods of screening latent TB infection are used in clinical practice and QuantiFERON (QFT) is one of them. Although QFT-2G was old type, QFT-3G was newly developed. Differences in characters between these two methods are not well understood. Objectives The objectives of this study are to compare QFT-2G and 3G as screening for latent TB infection in patients with rheumatoid arthritis (RA) before treatment with biologics and investigate the outcome after initiation of biologics treatment. Methods RA patients in whom QFT-2G or 3G was performed in our department were included in this study. Patient characteristics and result of QFT were compared between 2G group and 3G group. Chest CT findings and clinical course after initiation of biologics were investigated in patients with positive QFT. Results 178 cases and 57 cases were included in 2G group and 3G group, respectively. Mean age in 2G group and 3G group were 59.3 years old and 60.4 years old, respectively. 5 cases in 2G group have past history of TB infection and none in 3G group. 5 cases in 2G group (2.8%) and 6 cases in 3G group (10.5%) have positive results and there was a significant difference (p=0.027). 157 cases in 2G group (88.2%) and 42 cases in 3G group (73.7%) have negative results and there was a significant difference (p=0.011). In 10 cases that had positive results of QFT 2G or 3G, none had past history of TB, chest CT was normal in 4 cases and chemoprophylaxis of isoniazid (INH) was performed in 5 cases. Although biologics was used in 7 cases among 10 QFT-positive cases, no active TB was occurred until last observation. Used biologics were infliximab in 2 cases, etanercept in a case, abatacept in 3 cases and golimumab in a case. Conclusions Although higher positive rate and lower negative rate were seen in QFT-3G group compared with in QFT-2Ggroup, its usefulness in clinical practice is unknown. QFT-3G has high sensitivity and patients who were prescribed with INH are increased. There are several adverse events including hepatic toxicity in INH chemoprophylaxis. This study suggested that biologics therapy with INH chemoprophylaxis was acceptable in RA patients with positive QFT if they had no findings of suspected active TB in clinical sign or chest X-P and CT. Disclosure of Interest None Declared