Diagnosis and treatment of latent tuberculosis infection in arthritis patients treated with tumor necrosis factor antagonists in Korea

The risk of tuberculosis infection in Saudi patients receiving adalimumab, etanercept, and tocilizumab therapy

BACKGROUND

The risk of infection including tuberculosis (TB) infection or reactivation during biological therapy with the current various clinical application is a major concern. This risk may be higher in countries endemic to TB. Our aim of this study is to determine the risk of TB infection in patients receiving 3 biological treatments, Adalimumab, Etanercept and Tocilizumab.

METHODS

A retrospective cohort study extending over 2 years follow-up for all patients receiving Adalimumab, Etanercept and Tocilizumab for various clinical indications in a tertiary care center in Saudi Arabia.

RESULT

Over the period of 2015-2019, A total of 410 patients received Adalimumab, 271 received Etanercept and 58 patients received Tocilizumab. Rheumatoid arthritis was the most common indication for therapy in all groups and for Adalimumab the most common indication was inflammatory bowel disease, for Etanercept was psoriatic arthritis and for Tocilizumab was juvenile idiopathic arthritis. After a mean follow up period of 36 ± 8.9 months for patients receiving Adalimumab, 21.5 ± 8.4 months for patients receiving Etanercept and 21 ± 2.5 months for patients receiving Tocilizumab there were no reported cases of TB infection in all groups. Only one patient was diagnosed with latent TB 7 months later after starting Adalimumab and tow patients after starting Etanercept. The overall Interferon Gamma Release Assays (IGRA) positivity rate was 9.7%. There was significant association between IGRA positivity rate and patient age. The cutoff age in which IGRA positivity has significantly increased was 53.20 years.

CONCLUSION

In our study, patients receiving Etanercept, Adalimumab and Tocilizumab had no increased risk of TB infection. Only 0.3% of patients treated with Adalimumab and 0.9% of patients treated with Etanercept converted to a positive IGRA during therapy.

Prevalence of Latent Tuberculosis Infection (LTBI) in Mexican Patients With Rheumatoid Arthritis (RA)

INTRODUCTION

Patients with rheumatoid arthritis (RA) are at increased risk of developing tuberculosis, and even more so if they receive biological agents. In Mexico, the prevalence of latent tuberculosis infection (LTBI) in RA diagnosed by interferon-gamma release assay (IGRA) is largely unknown. The objective was to determine LTBI prevalence and the associated risk factors in rheumatoid arthritis patients.

METHODS

A cross-sectional study was performed comprising 82 patients with RA who attended the rheumatology service at a second-level hospital. Demographic characteristics, comorbidity, Bacillus Calmette-Guerin (BCG) vaccination and smoking history, type of treatment, disease activity and functional capacity were investigated. The Disease Activity Score 28 and the Health Assessment Questionnaire-Disability Index were applied for the estimate of RA activity and functional capacity. Further information was compiled from the electronic medical records and personal interviews. LTBI was determined by QuantiFERON TB Gold Plus (QIAGEN, Germantown, USA).

RESULTS

Prevalence of LTBI was 14% (95% confidence interval (CI): 8.6% to 23.9%). Factors associated with LTBI were history of smoking (odds ratio (OR) = 6.63 95% CI 1.01 to 43.3) and disability score (OR = 7.19 95%CI 1.41 to 36.6).

CONCLUSIONS

The prevalence of LTBI in Mexican patients with RA was 14%. Our results suggest prevention of smoking and functional incapacity could reduce the risk of LTBI. Further research could endorse our results.

The risk of tuberculosis infection in 410 Saudipatients receiving adalimumab therapy

BACKGROUND

Adalimumab is a fully humanized monoclonal antibody inhibitor of tumor necrosis factor-a used to treat various autoimmune disorders. Adalimumab poses a risk for tuberculosis (TB) infection, especially in countries where TB is endemic.

OBJECTIVE

Determine the rate of TB infection after adalimumab therapy in Saudi Arabia.

DESIGN

Medical record review.

SETTINGS

Tertiary care center in Riyadh.

PATIENTS AND METHODS

Demographic and clinical data were retrieved from the electronic healthcare records of all patients who received adalimumab treatment from 2015 to 2019.

MAIN OUTCOME MEASURES

Occurrence of TB after adalimumab therapy.

SAMPLE SIZE

410 patients (median ([QR] age, 37 [28], range 4-81 years), 40% males RESULTS: Rheumatoid arthritis was the most frequent indication (n=153, 37%). The patients were followed for a mean of 36 (8.9) months. No case of TB infection or reactivation was observed. An inter-feron-gamma release assay (IGRA) was requested in 353/391 (90.3%) patients, prior to initiating therapy. The IGRA was positive in 26 cases (6.6%). The IGRA-positive patients received isoniazid prophylactically. Bacterial infectious complications of adalimumab therapy occurred in 12 (2.9%) patients. Urinary tract infection was the most frequent complication (culture requested in 48 patients, positive in 8).

CONCLUSION

Adalimumab treatment was not associated with a risk of TB disease or TB reactivation in our cohort over the follow-up observation period. No TB reactivation occurred with adalimumab therapy when TB prophylaxis was used. The positive IGRA rate in patients on adalimumab treatment was low (7%).

LIMITATIONS

Single center and one geographical area in Saudi Arabia.

CONFLICT OF INTEREST

None.

Risk of Tuberculosis Development in Patients with Rheumatoid Arthritis Receiving Targeted Therapy: a Prospective Single Center Cohort Study

BACKGROUND

Patients with rheumatoid arthritis (RA) undergoing targeted therapy have a higher risk of developing tuberculosis (TB). This requires diagnosis and treatment of latent tuberculosis infection (LTBI). We aimed to evaluate whether diagnosis and treatment of LTBI in RA are effective in Korea, and to estimate the risk of TB development by calculating the incidence rate of active TB among RA patients receiving targeted therapy.

METHODS

We analyzed data from two prospective cohort studies of RA patients who received biologic disease-modifying antirheumatic drugs (bDMARDs) or Janus kinase (JAK) inhibitor. We selected new starters of targeted therapy and classified them into three groups receiving tumor necrosis factor (TNF) inhibitor, non-TNF inhibitor, and JAK inhibitor, respectively. We then compared LTBI prevalence, treatments, and active TB incidence during first-line therapy in each group.

RESULTS

A total of 765 RA patients (574 TNF inhibitor users, 132 non-TNF inhibitor users, and 59 JAK inhibitor users) were included in this study. Observation periods were 1,255.2 person-years (PYs), 264.7 PYs, and 53.3 PYs, respectively. All 765 patients underwent LTBI screening, and the positivity rate was 26.5% (n = 203). Of the 203 LTBI-positive patients, 189 (93.1%) received treatment. Only one patient, who was in the TNF inhibitor group, and was negative for the interferon gamma release assay (IGRA), did not receive LTBI treatment and developed active TB during follow-up.

CONCLUSION

Although the prevalence of LTBI in RA patients who started targeted therapy was slightly elevated, the Korean guidelines specifying LTBI screening and treatment were effective in preventing latent TB from becoming active.

Risk of tuberculosis in patients treated with TNF-α antagonists: a systematic review and meta-analysis of randomised controlled trials

OBJECTIVES

An increased risk of tuberculosis (TB) has been reported in patients treated with TNF-α antagonists, an issue that has been highlighted in a WHO black box warning. This review aimed to assess the risk of TB in patients undergoing TNF-α antagonists treatment.

METHODS

A systematic literature search for randomised controlled trials (RCTs) was performed in MEDLINE, Embase and Cochrane library and studies selected for inclusion according to predefined criteria. ORs with 95% CIs were calculated using the random-effect model. Subgroup analyses considered the effects of drug type, disease and TB endemicity. The quality of evidence was assessed using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

29 RCTs involving 11 879 patients were included (14 for infliximab, 9 for adalimumab, 2 for golimumab, 1 for etanercept and 3 for certolizumab pegol). Of 7912 patients allocated to TNF-α antagonists, 45 (0.57%) developed TB, while only 3 cases occurred in 3967 patients allocated to control groups, resulting in an OR of 1.94 (95% CI 1.10 to 3.44, p=0.02). Subgroup analyses indicated that patients of rheumatoid arthritis (RA) had a higher increased risk of TB when treated with TNF-α antagonists (OR 2.29 (1.09 to 4.78), p=0.03). The level of the evidence was recommended as 'low' by the GRADE system.

CONCLUSIONS

Findings from our meta-analysis indicate that the risk of TB may be significantly increased in patients treated with TNF-α antagonists. However, further studies are needed to reveal the biological mechanism of the increased TB risk caused by TNF-α antagonists treatment.

The cascade of care in diagnosis and treatment of latent tuberculosis infection: a systematic review and meta-analysis

BACKGROUND

WHO estimates that a third of the world's population has latent tuberculosis infection and that less than 5% of those infected are diagnosed and treated to prevent tuberculosis. We aimed to systematically review studies that report the steps from initial tuberculosis screening through to treatment for latent tuberculosis infection, which we call the latent tuberculosis cascade of care. We specifically aimed to assess the number of people lost at each stage of the cascade.

METHODS

We did a systematic review and meta-analysis of study-level observational data. We searched MEDLINE (via OVID), Embase, and Health Star for observational studies, published between 1946 and April 12, 2015, that reported primary data for diagnosis and treatment of latent tuberculosis infection. We did meta-analyses using random and fixed effects analyses to identify percentages of patients with latent tuberculosis infection completing each step in the cascade. We also estimated pooled proportions in subgroups stratified by different characteristics of interest to assess risk factors for losses.

RESULTS

We identified 58 studies, describing 70 distinct cohorts and 748 572 people. Steps in the cascade associated with greater losses included completion of testing (71·9% [95% CI 71·8-72·0] of people intended for screening), completion of medical evaluation (43·7% [42·5-44·9]), recommendation for treatment (35·0% [33·8-36·4]), and completion of treatment if started (18·8% [16·3-19·7]). Steps with fewer losses included receiving test results, referral for evaluation if test positive, and accepting to start therapy if recommended. Factors associated with fewer losses were immune-compromising medical indications, being part of contact investigations, and use of rifamycin-based regimens.

INTERPRETATION

We identify major losses at several steps in the cascade of care for latent tuberculosis infection. Improvements in management of latent tuberculosis will need programmatic approaches to address the losses at each step in the cascade.

FUNDERS

Canadian Institutes of Health Research.

Initiation and completion rates for latent tuberculosis infection treatment: a systematic review

BACKGROUND

Control of latent tuberculosis infection (LTBI) is an important step towards tuberculosis elimination. Preventive treatment will prevent the development of disease in most cases diagnosed with LTBI. However, low initiation and completion rates affect the effectiveness of preventive treatment. The objective was to systematically review data on initiation rates and completion rates for LTBI treatment regimens in the general population and specific populations with LTBI.

METHODS

A systematic review of the literature (PubMed, Embase) published up to February 2014 was performed.

RESULTS

Forty-five studies on initiation rates and 83 studies on completion rates of LTBI treatment were found. These studies provided initiation rates (IR) and completion rates (CR) in people with LTBI among the general population (IR 26-99 %, CR 39-96 %), case contacts (IR 40-95 %, CR 48-82 %), healthcare workers (IR 47-98 %, CR 17-79 %), the homeless (IR 34-90 %, CR 23-71 %), people who inject drugs (IR 52-91 %, CR 38-89 %), HIV-infected individuals (IR 67-92 %, CR 55-95 %), inmates (IR 7-90 %, CR 4-100 %), immigrants (IR 23-97 %, CR 7-86 %), and patients with comorbidities (IR 82-93 %, CR 75-92 %). Generally, completion rates were higher for short than for long LTBI treatment regimens.

CONCLUSION

Initiation and completion rates for LTBI treatment regimens were frequently suboptimal and varied greatly within and across different populations.

Isoniazid toxicity and TB development during biological therapy of patients with psoriasis in Colombia

Background The use of biological therapy has been linked with an increased risk of tuberculosis (TB) reactivation. Objective The aim of this study was to present the follow-up results for Isoniazid (INH) chemoprophylaxis in patients with psoriasis receiving different biological therapies. Methods In this prospective observational study, patients with latent tuberculosis infection (LTBI) were given INH chemoprophylaxis between two and nine months prior to the beginning of biological therapy. All patients were followed up monthly for any signs or symptoms of active TB or INH toxicity. Results A total of 101 patients, 44.5% females, with a mean age of 46.9 ± 11.5 years (20-73) were enrolled. LTBI was identified in 100 patients (99%), of whom 81.2% completed nine months of chemoprophylaxis. Three patients (2.9%) developed active TB and 17 patients (16.8%) developed intolerance or toxicity related to INH. Conclusions Chemoprophylaxis with INH seems to be effective and safe for the prevention of most TB reactivations in individuals with LTBI receiving biological therapy, but toxicity must be monitored during follow-up.

Diagnosis and treatment of latent tuberculosis infection

A small number of viable tuberculosis bacilli can reside in an individual with latent tuberculosis infection (LTBI) without obvious clinical symptoms or abnormal chest radiographs. Diagnosis and treatment for LTBI are important for tuberculosis (TB) control in public and private health, especially in high-risk populations. The updated 2014 Korean guidelines for TB recommend that tuberculin skin tests, interferon-gamma release assays, or a combination of the two can be used for LTBI diagnosis according to age and immune status of the host as well as TB contact history. The regimens for LTBI treatment include isoniazid, rifampicin, or isoniazid/rifampicin. However, results of drug susceptibility test from the index case must be considered in selecting the appropriate drug for recent contacts. Standardized LTBI diagnosis and treatment based on the new 2014 guidelines will contribute to the effective TB control in Korea as well as to the establishment of updated guidelines.

Follow-up results of isoniazid chemoprophylaxis during biological therapy in Colombia

The use of biological therapy has been linked with an increased risk of tuberculosis (TB) reactivation. The aim of this study was to present the follow-up results for isoniazid (INH) chemoprophylaxis in patients receiving different biological therapies. In this prospective observational study, patients with latent tuberculosis infection (LTBI) were given INH chemoprophylaxis between 2 and 9 months prior to the beginning of biological therapy. All patients were followed up monthly for any signs or symptoms of active TB or INH toxicity. A total of 221 patients, 122 females (55.2 %), with a mean age of 46.8 ± 11.3 years (16-74) were enrolled. LTBI was identified in 218 patients (98.7 %), all of whom received INH chemoprophylaxis. Seven patients (3.2 %) developed active tuberculosis, and 32 (17.2 %) patients developed intolerance or toxicity related to INH. Chemoprophylaxis with INH seems to be effective and safe for the prevention of most TB reactivation in individuals with LTBI, but toxicity must be monitored during follow-up.

The risk of tuberculosis in Korean patients with inflammatory bowel disease receiving tumor necrosis factor-α blockers

The aims of this study were to assess the risk of tuberculosis (TB) and the status of latent tuberculosis infection (LTBI) in Korean patients with inflammatory bowel disease (IBD) receiving tumor necrosis factor (TNF)-α blockers. We reviewed medical records of 525 Korean IBD patients (365 TNF-α blocker naïve and 160 TNF-α blocker exposed) between January 2001 and December 2013. The crude incidence of TB was significantly higher in IBD patients receiving TNF-α blockers compared to TNF-α-blocker-naïve patients (3.1% vs. 0.3%, P=0.011). The mean incidence of TB per 1,000 patient-years was 1.84 for the overall IBD population, 4.89 for TNF-α blocker users, and 0.45 for TNF-α-blocker-naïve patients. The adjusted risk ratio of TB in IBD patients receiving TNF-α blocker was 11.7 (95% confidence interval, 1.36-101.3). Pulmonary TB was prevalent in patients treated with TNF-α blockers (80.0%, 4/5). LTBI was diagnosed in 17 (10.6%) patients, and none of the 17 LTBI patients experienced reactivation of TB during treatment with TNF-α blockers. Treatment with TNF-α blockers significantly increased the risk of TB in IBD patients in Korea. De novo pulmonary TB infection was more prevalent than reactivation of LTBI, suggesting an urgent need for specific recommendations regarding TB monitoring during TNF-α blocker therapy.

Diagnosis and Treatment of Latent Tuberculosis Infection due to Initiation of Anti-TNF Therapy

Patients with immune-mediated inflammatory diseases (IMIDs) are increasingly being treated with anti-tumor necrosis factor (TNF) agents and are at increased risk of developing tuberculosis (TB). Therefore, diagnosis and treatment of latent TB infection (LTBI) is recommended in these patients due to the initiation of anti-TNF therapy. Traditionally, LTBI has been diagnosed on the basis of clinical factors and a tuberculin skin test. Recently, interferon-gamma releasing assays (IGRAs) that can detect TB infection have become available. Considering the high-risk of developing TB in patients on anti-TNF therapy, the use of both a tuberculin skin test and an IGRA should be considered to detect and treat LTBI in patients with IMIDs. The traditional LTBI treatment regimen consisted of isoniazid monotherapy for 9 months. However, shorter regimens such as 4 months of rifampicin or 3 months of isoniazid/rifampicin are increasingly being used to improve treatment completion rates. In this review, the screening methods for diagnosing latent and active TB before anti-TNF therapy in patients with IMIDs will be briefly described, as well as the current LTBI treatment regimens, the recommendations for managing TB that develops during anti-TNF therapy, the necessity of regular monitoring to detect new TB infection, and the re-initiation of anti-TNF therapy in patients who develop TB.

Diagnosis and Treatment of Latent Tuberculosis Infection in Patients with Inflammatory Bowel Diseases due to Initiation of Anti-Tumor Necrosis Factor Therapy

Patients with intractable inflammatory bowel diseases (IBD) are increasingly being treated with anti-tumor necrosis factor (TNF) agents and are at increased risk of developing tuberculosis (TB). Therefore, diagnosis and treatment of latent TB infection (LTBI) is recommended in patients due to the initiation of anti-TNF therapy. Traditionally, LTBI has been diagnosed on the basis of clinical factors and a tuberculin skin test. Recently, interferon-gamma releasing assays (IGRAs) that can detect TB infection have become available. Considering the high-risk of developing TB in patients on anti-TNF therapy, the use of both a tuberculin skin test and an IGRA should be considered to detect and treat LTBI in patients with IBD due to the initiation of anti-TNF therapy. The traditional LTBI treatment regimen has consisted of isoniazid monotherapy for 9 months. However, shorter regimens such as 4 months of rifampicin or 3 months of isoniazid/rifampicin have been used increasingly to improve treatment completion rates. In this review, the incidence of TB and the prevalence of LTBI in patients with IBD will be briefly described, as well as methods for diagnosing latent and active TB before anti-TNF therapy, current LTBI treatment regimens, recommendations for managing TB that develops during anti-TNF therapy, the necessity of regular monitoring to detect new TB infection, and the re-initiation of anti-TNF therapy in patients who develop TB.

Short-course treatment of latent tuberculosis infection in patients with rheumatic conditions proposed for anti-TNF therapy

Tuberculosis reactivation is a serious threat in patients treated with anti-tumour necrosis factor therapy. A 6-month regimen with isoniazid is considered as the standard of care, but patient adherence is a major shortcoming. We carried out an open-label, single-arm intervention study to assess the efficacy, the completion rate and the tolerability of a 3-month regimen with isoniazid plus rifampin. Seventy-eight patients with rheumatic conditions proposed for anti-tumour necrosis factor (TNF) therapy and at risk of tuberculosis reactivation were offered to participate in the study. Nine patients were excluded due to deficit of glucose-6-phosphate dehydrogenase (n = 1), salicylate hypersensitivity (n = 1), declining to participate (n = 5) or preferring a 6-month isoniazid regimen (n = 6). Sixty-nine patients were treated with a 3-month regimen with isoniazid and rifampin. No cases of tuberculosis were observed after a mean follow-up of 90 months (range from 66 to 121 months). Sixty (87 %) patients completed the therapy. Nine (13 %) patients discontinued the therapy due to rifampin hypersensitivity (n = 1), symptomatic grade 3-4 hepatotoxicity (n = 2), abdominal discomfort (n = 2), pruritus (n = 1), arthritis (n = 1) and personal concerns (n = 2). A short course treatment with isoniazid and rifampin provided efficacy, good tolerability and good completion rate in patients with rheumatic conditions proposed for anti-TNF therapy.

Risk of tuberculosis infection in anti-TNF-α biological therapy: from bench to bedside

Anti-tumor necrosis factor-α (TNF-α) biological agents, including soluble TNF-α receptors and anti-TNF-α monoclonal antibodies, bring new hope for treating rheumatic diseases such as rheumatoid arthritis, but also increase the risk of infection, especially tuberculosis (TB) infection. Recent findings have shown that the physiological TNF-mediated signaling was somehow impaired by TNF antagonists, leading to the exacerbation of chronic infection associated with aberrant granuloma formation and maintenance. Although both receptor and antibody agents appear to pose an equally high risk in causing development of new TB infections, monoclonal anti-TNF-α antibody seems more inclined to reactivate latent TB infection. This review is focused on the underlying mechanisms that cause the TB risk in the anti-TNF-α therapy and also the strategies to deal with it, with the aim of reducing the TB incidence during anti-TNF-α biological therapies.

Interferon-γ release assay in the diagnosis of latent tuberculosis infection in arthritis patients treated with tumor necrosis factor antagonists in Korea

The aim of this study was to evaluate the usefulness of the interferon-γ release assay (IGRA) for the diagnosis of latent tuberculosis infection (LTBI) in arthritis patients who received tumor necrosis factor (TNF) antagonist in Korea. The study involved 107 consecutive patients: 61 (57%) with ankylosing spondylitis and 46 (43%) with rheumatoid arthritis. Screening tests were performed including the tuberculin skin test (TST), the QuantiFERON-TB Gold In-Tube (QFT-IT) test, and chest radiography. A positive QFT-IT test result, regardless of TST results, was considered an indication for LTBI treatment. If the QFT-IT results were indeterminate, a positive TST was regarded as an indication for LTBI treatment. A Bacillus Calmette-Guérin (BCG) scar was found in 63 patients (59%). LTBI treatment was performed in 37 patients (35%), including 36 with positive QFT-IT results and one with indeterminate QFT-IT and positive TST results. No patients developed tuberculosis during a median of 18 months (range, 13-26 months) of TNF antagonist therapy. In 16 patients who had positive TST and negative QFT-IT results, TNF antagonists were given without LTBI treatment. Tuberculosis did not occur, even in these patients, during a median of 24.5 months (range, 15-33.5 months) of TNF antagonist therapy. IGRA may be used instead of TST for the diagnosis of LTBI in patients before starting TNF antagonists in countries where tuberculosis prevalence is intermediate and the BCG vaccination is mandatory at birth, such as in Korea.

QuantiFERON TB gold testing for tuberculosis screening in an inflammatory bowel disease cohort in the United States

BACKGROUND

Reactivation of latent Mycobacterium tuberculosis (TB) is a rare, yet devastating infectious complication associated with anti-tumor necrosis factor alpha (TNF-α) therapy. We evaluated the performance of the QuantiFERON TB Gold test (QFT-G) for TB screening in a cohort of inflammatory bowel disease (IBD) patients in the United States.

METHODS

We performed a retrospective, observational study of patients initiated and/or maintained on an anti-TNF-α agent in a single IBD referral center and recorded the frequency and the test results of QFT-G testing and the rate of TB reactivation.

RESULTS

512 QFT-G tests were done in 340 patients. Five patients (1.5%) had a positive, nine (2.7%) indeterminate, and 326 patients (95.8%) had a negative QFT-G. After a mean follow-up of 17 months there was one case of TB reactivation (0.3%). The use of immunosuppressive therapy or anti-TNF therapy at the time of testing did not affect the results of the QFT-G testing. Test-retest had substantial concordance (κ = 0.72). 25% of patients (n = 85) had TST testing. Concordance between the TST and QFT-G was found to be moderate (κ = 0.4152, P = 0.0041).

CONCLUSIONS

Most patients with negative QFT-G tolerated anti-TNF therapy with no evidence of TB reactivation. Concomitant use of immunosuppressive therapy or anti-TNF did not seem to affect QFT-G results. One patient had an indeterminate QFT-G while on infliximab and later developed miliary TB. Concordance with TST is moderate.

Positive Conversion of Tuberculin Skin Test and Performance of Interferon Release Assay to Detect Hidden Tuberculosis Infection During Anti-Tumor Necrosis Factor Agent Trial

Objectives.

To evaluate tuberculin skin tests (TST) and interferon-γ (IFN-γ) assay in the detection of latent tuberculosis (TB) infection during tumor necrosis factor (TNF) antagonist treatment in Korean patients with initial negative TST result.

Methods.

Eighty-six patients with rheumatic diseases who had received anti-TNF agents for over one year were investigated. Clinical data were obtained from medical records. All patients received followup TST, and IFN-γ assay was performed in 64.

Results.

The study population consisted of 40 rheumatoid arthritis (RA), 34 ankylosing spondylitis (AS), 9 juvenile rheumatoid arthritis (JRA), and 3 other patients. The TST converted to positive in 28 (32.6%) patients. There was no significant variation between TST conversion rate and all risk factors. Although there was no statistical significance, the odds of the TST conversion rate tended to increase with the duration of TNF antagonist administration. Nine (14.1%) of 64 patients who performed an IFN-γ assay had positive results. Among 28 TST positive conversion cases, 4 patients with AS and 1 with psoriatic arthritis had positive IFN-γ assay results, and one of them developed miliary TB. However, none of the 4 RA patients with positive IFN-γ assay showed TST conversion. There was 68.6% agreement (kappa = 0.29, p = 0.02) between TST and IFN-γ assay results.

Conclusion.

Serial TST with IFN-γ assay may be useful to identify false-negative response to cases of latent Mycobacterium tuberculosis infection and new TB infections in patients with immune mediated inflammatory diseases during longterm anti-TNF therapy, especially in areas with intermediate TB burden.