Performance of two commercial blood IFN-γ release assays for the detection of Mycobacterium tuberculosis infection in patient candidates for anti-TNF-α treatment

Peritoneal Tuberculosis during Infliximab Treatment in a Patient with Ulcerative Colitis Despite a Negative Quantiferon Test

Infliximab is an IgG1 antitumor necrosis factor monoclonal antibody that is commonly used to treat inflammatory bowel disease (IBD) and other autoimmune disorders. However, it is known to increase the risk of reactivation of latent tuberculosis (LTBI) due to its capability to disrupt TB granulomas. We describe a case of extrapulmonary TB in a patient with ulcerative colitis who was treated with Infliximab after a negative Quantiferon Test. In addition, we report briefly on the current controversy about the appropriateness, interval, and methods for the repeated screening of latent TB in IBD patients that are treated with antitumor necrosis factor alpha (TNF-α) antibodies.

[Functional immunoassays in the setting of infectious risk and immunosuppressive therapy of non-HIV immunocompromised patients]

The holistic approach of the human immune system is based on the study of its components collectively driving a functional response to an immunogenic stimulus. To appreciate a specific immune dysfunction, a condition is mimicked ex vivo and the immune response induced is assessed. The application field of such assays are broad and expanding, from the diagnosis of primary and secondary immunodeficiencies, immunotherapy for cancer to the management of patients at-risk for infections and vaccination. These assays are immune monitoring tools that may contribute to a personalised and precision medicine. The purpose of this review is to describe immune functional assays available in the setting of non-HIV acquired immune deficiency. First, we will address the use of theses assays in the diagnosis of opportunistic infections such as viral reactivation. Secondly, we will report the usefulness of these assays to assess vaccine efficacy and to manage immunosuppressive therapies.

Tuberculosis and Biologic Therapies: Anti-Tumor Necrosis Factor-α and Beyond

Biologic drugs have revolutionized the treatment of certain hematologic, autoimmune, and malignant diseases, but they may place patients at risk for reactivation or acquisition of tuberculosis. This risk is highest with the tumor necrosis factor-alpha (TNF-α) inhibitors. Amongst this class of drugs, the monoclonal antibodies (infliximab, adalimumab, golimumab) and antibody fragment (certolizumab) carry an increased risk compared to the soluble receptor fusion molecule, etanercept. Treatment of latent TB is critical to decrease the risk of reactivation. Data continues to emerge regarding tuberculosis risk associated with novel biologics targeting cytokines involved in tuberculosis control.

Superiority of Interferon Gamma Assay Over Tuberculin Skin Test for Latent Tuberculosis in Inflammatory Bowel Disease Patients in Brazil

BACKGROUND AND AIMS

To compare tuberculin skin test (TST) and interferon gamma release assay (IGRA) in the screening of LTBI among patients with inflammatory bowel disease (IBD) in an endemic area for tuberculosis, to evaluate the need for repeating tests during anti-TNFα, therapy, and to check whether the results may be affected by immunosuppression.

METHODS

A cross-sectional study of 110 IBD patients and 64 controls was conducted in Rio de Janeiro, Brazil. The TST was administered after the Quantiferon(^®)-TB Gold In-tube test was performed.

RESULTS

TST and IGRA agreement was poor regarding diagnosis (kappa: control = 0.318; UC = 0.202; and CD = - 0.093), anti-TNFα therapy (kappa: with anti-TNFα = 0.150; w/o anti-TNFα = - 0.123), and immunosuppressive therapy (IST) (kappa: with IS = - 0.088; w/o IS = 0.146). Indeterminate IGRA was reported in four CD patients on IST. Follow-up tests after anti-TNFα identified conversion in 8.62% using TST and 20.0% using IGRA. Considering IGRA as a criterion standard, TST showed low sensitivity (19.05%) and positive predictive value (PPV) (21.05%). LTBI detection remarkably improved when IGRA was added to TST (sensitivity of 80.95% and PPV of 53.13%). Results were particularly relevant among CD patients where rates started from zero to reach sensitivity and PPV of more than 60%.

CONCLUSION

IGRA alone was more effective to detect LTBI than TST alone and had an overall remarkable added value as an add-on sequential test, particularly in CD patients. While cost-effectiveness of these strategies remains to be evaluated, IGRA appears to be justified in CD prior to and during anti-TNFα therapy, where tuberculosis is endemic.

Indeterminate QuantiFERON-TB Gold Increases Likelihood of Inflammatory Bowel Disease Treatment Delay and Hospitalization

BACKGROUND

QuantiFERON-TB Gold (QFTG) is a blood test used to diagnose latent tuberculosis infection (LTBI) prior to TNF-α inhibitor (anti-TNF) initiation. We sought to determine factors associated with indeterminate QFTG results in inflammatory bowel disease (IBD) patients and whether indeterminate results are associated with IBD-related morbidity.

METHODS

This nested case-control study included IBD patients who underwent QFTG testing. Cases were patients with indeterminate QFTG and controls were those with negative QFTG. The association of demographic and clinical data with indeterminate QFTG result was assessed using logistic regression. We examined the clinical impact of indeterminate QFTG results on risk of hospitalization and delay in anti-TNF initiation using inverse probability-of-treatment weighting (IPTW) regression.

RESULTS

We identified 411 patients with QFTG testing (320 negative, 80 indeterminate, and 11 positive results). No patient with an indeterminate result subsequently had LTBI. Systemic corticosteroid use (OR, 4.4; 95% CI, 2.0-9.6) and hospitalization at the time of QFTG (OR, 3.8; 95% CI, 1.9-7.7) were associated with indeterminate QFTG, while immunomodulator use was nearly statistically significant (OR, 3.1; 95% CI, 0.9-9.8) and anti-TNF use was not (OR, 0.9; 95% CI, 0.2-4.6). After IPTW adjustment, indeterminate QFTG was associated with a 23.1% (95% CI, 8.2%-37.9%) greater probability of delay in anti-TNF initiation beyond 30 days and an 11.9% (95% CI, 0.6%-23.1%) greater probability of hospitalization within 60 days.

CONCLUSIONS

Systemic corticosteroid use and hospitalization were associated with an indeterminate QFTG result. Indeterminate QFTG results were associated with delayed anti-TNF initiation and subsequent hospitalization.

Use of IFN-γ and IP-10 detection in the diagnosis of latent tuberculosis infection in patients with inflammatory rheumatic diseases

OBJECTIVES

Biologic agents are used against rheumatic diseases, however, they increase the risk of developing severe infections and diseases such as tuberculosis. We aimed to determine the benefits of IP-10 detection to diagnose latent tuberculosis infection (LTBI) in patients with inflammatory rheumatic diseases on different immunosuppressive drug regimens, and compare these results with IFN-γ detection.

MATERIALS AND METHODS

We included 64 patients with inflammatory rheumatic diseases. We used QuantiFERON Gold In-Tube (QFN-G-IT) and T-SPOT.TB to detect IFN-γ production, and an in-house ELISA for IP-10 detection from the previous QFN-G-IT stimulated samples. We assessed the combined use of IFN-γ release assays (IGRAs) and IP-10 test, and analyzed the influence of immunotherapy on the tests performance.

RESULTS

We obtained 34.9% positive results by T-SPOT.TB, 25.0% by QFN-G-IT and 31.3% by IP-10 test. The combined use of IGRAs and IP-10 detection increased significantly the amount of positive results (p < 0.0001). Treatment intake had no significant effect on in vitro tests (p > 0.05).

CONCLUSIONS

IP-10 and IFN-γ detection is comparable and their combined use could increase the number of positive results in the diagnosis of LTBI in rheumatic patients. The tested assays were not influenced by rheumatoid immunosuppressive therapy. Thus, IP-10 could be of use in the development of new and improved LTBI diagnostic tools.

Biologic Agents and Tuberculosis

Treatment with biologic agents, in particular tumor necrosis factor alpha (TNF-α) inhibitors, is associated with an increased risk of tuberculosis (TB), and screening and treatment for latent TB infection (LTBI) in patients undergoing such treatment is therefore indicated. The risk of TB associated with different biologics varies significantly, with the highest relative risks, 29.3 and 18.6, associated with adalimumab and infliximab, respectively. The risk of TB with newer TNF-α inhibitors and other biologics appears to be lower. Performance of LTBI screening tests is affected by immune-mediated inflammatory diseases and immunosuppressive therapy in patients due to commence TNF-α inhibitor treatment. Interferon gamma release assays (IGRAs) have a higher specificity than the tuberculin skin test (TST) in patients with Bacillus Calmette–Guérin (BCG) vaccination and have probably a better sensitivity than TST in immunosuppressed patients. LTBI screening programs prior to commencement of anti-TNF-α treatment significantly reduce the incidence of TB, but the optimal screening algorithm, in particular the question of whether a combination of IGRA and TST or a single test only should be used, is a matter of ongoing debate. Use of TST in combination with IGRA is justified to increase sensitivity. Repeat testing for LTBI should be limited to patients at increased risk of TB. If TB develops during anti-TNF-α treatment, it is more likely to be disseminated and extrapulmonary than are other TB cases. Discontinuation of anti-TNF-α treatment in patients diagnosed with TB is associated with an increased risk of immune reconstitution inflammatory syndrome, which is probably best managed by reintroduction of anti-TNF-α treatment.

Screening Optimization of Latent Tuberculosis Infection in Rheumatoid Arthritis Patients

Objective. Rheumatoid arthritis (RA) patients are at increased risk of latent tuberculosis infection (LTBI) but there are no clear guidelines for LTBI screening with Tuberculin Skin Test (TST) or Quantiferon TB Gold testing (QFT-G). Methods. A retrospective study was conducted in a high risk, largely foreign-born, inner city, RA population. After screening 280 RA patients, 134 patients who had both TST and QFT-G testing performed during their initial evaluation were included. Results. Out of 132 RA patients included in our analysis, 50 (37.8%) patients were diagnosed with LTBI with either positive TST 42 (31.8%) or QFT-G 23 (17.4%). 15 (11.4%) were positive and 82 (62.1%) were negative for both tests. The agreement between TST and QFT-G was 73.5% (Kappa 0.305, CI = 95% 0.147-0.463, p = 0.081).  Conclusions. There was low-moderate agreement (κ = 0.305) between TST and QFT-G. In the absence of clearly defined gold standard and limitations associated with both tests, we propose early screening with both tests for patients who need prompt treatment with BRMs. Patients who are not immediate candidates for BRM treatment may be safely and cost effectively screened with a two-step process: initial screening with TST and if negative, IGRA testing. Patients positive for either test should be promptly treated.

Consensus Document on Prevention and Treatment of Tuberculosis in Patients for Biological Treatment

Tuberculosis risk is increased in patients with chronic inflammatory diseases receiving any immunosuppressive treatment, notably tumor necrosis factor (TNF) antagonists therapy. Screening for the presence of latent infection with Mycobacterium tuberculosis and targeted preventive treatment to reduce the risk of progression to TB is mandatory in these patients. This Consensus Document summarizes the current knowledge and expert opinion of biologic therapies including TNF-blocking treatments. It provides recommendations for the use of interferon-gamma release assays (IGRA) and tuberculin skin test (TST) for the diagnosis of latent tuberculosis infection in these patients, and for the type and duration of preventive therapy.

T-cell profiling and the immunodiagnosis of latent tuberculosis infection in patients with inflammatory bowel disease

BACKGROUND

Factors associated with performance of interferon-γ release assays (IGRA) and the tuberculin skin test (TST) in screening for latent tuberculosis infection in patients with inflammatory bowel diseases (IBD) are still poorly understood. The influence of peripheral T-cell subset counts on the results also remain unclear.

METHODS

Prospective single-center study in 205 patients with IBD. Latent tuberculosis infection screening included a chest radiograph, TST (retest if negative), and 2 IGRAs: QuantiFERON-TB Gold In-Tube (QFT-GIT) and TSPOT-TB (TSPOT). T-cell subpopulations were determined by flow cytometry.

RESULTS

Twenty-one (10.2%) patients had an abnormal chest radiograph, 55 (26.8%) had a positive TST, 16 (7.8%) had a positive QFT-GIT, and 25 (12.6%) had a positive TSPOT. TST positivity was lower in patients on ≥2 immunosuppressants compared with the controls (5-aminosalicylic acid treatment) (10.4% versus 38.2%, respectively) (P = 0.0057). No other drugs influenced TST or IGRA positivity. In patients on corticosteroid treatment, anti-TNF treatment, or ≥2 immunosuppressants, IGRAs detected 10 cases of latent tuberculosis infection not identified by TST. TSPOT and QFT-GIT increased yield by 56% and 22%, respectively. No significant differences in T-cell subpopulations were found between patients with positive or negative TST or TSPOT results. However, patients with positive QFT-GIT findings had more CD8 T cells (mean, 883 ± 576 versus 484 ± 385 cells per microliter in patients with negative results) (P = 0.022).

CONCLUSIONS

IGRAs can improve TST-based screening in patients with IBD on immunosuppressive therapy. A low CD8 count can affect QFT-GIT results. We suggest combining TSPOT and TST screening in patients with IBD on immunosuppressants.

Cost-effectiveness of QuantiFERON testing before initiation of biological therapy in inflammatory bowel disease

BACKGROUND

Anti-tumor necrosis factor α drugs are known to reactivate latent tuberculosis (TB). Current guidelines recommend screening for latent tuberculosis infection, with either tuberculin skin test (TST) or interferon gamma release assays such as QuantiFERON-TB Gold (QFT-G). Given the high rates of anergy to TST among immunosuppressed inflammatory bowel disease (IBD) patients, there is considerable interest in evaluating the superiority of interferon gamma release assays over TST in this patient population to diagnose latent tuberculosis infection. We compared the performance of TST and QFT-G for screening latent TB among immunosuppressed IBD patients based on prevalence, mortality risk from reactivation TB, and costs.

METHODS

A decision analytical model was constructed to compare 1-year outcomes and costs of using TST or interferon gamma release assay in an immunosuppressed IBD population.

RESULTS

Under the base case scenario, for every 1000 patients screened, the QFT-G strategy resulted in 0.53 deaths from reactivation TB compared with 1.92 deaths using TST. The QFT-G strategy results in 1.85 reactivation TB versus 6.7 reactivation TB using TST. The model was not sensitive to background prevalence of latent TB. The cost of QFT-G would have to be more than double for the TST strategy to become more cost effective. QFT-G also remains the cost-effective option unless the sensitivity of the TST improves by 400%.

CONCLUSIONS

Under a broad range of parameter values, the QFT-G strategy dominates the TST strategy in cost-effectiveness. Consideration should be given to QFT-G as the preferred method of identifying latent TB in all immunosuppressed IBD patients.

Screening for Latent Tuberculosis Infection in Patients with Chronic Inflammatory Arthritis: Discrepancies Between Tuberculin Skin Test and Interferon-γ Release Assay Results

Objective.

Screening for latent tuberculosis infection (LTBI) is mandatory before initiating biologics in patients with chronic inflammatory arthritis (CIA). However, few studies have evaluated the discrepancies between the results of tuberculin skin test (TST) and interferon-γ release assays (IGRA) in these patients. The purpose of our study was to investigate factors associated with TST and IGRA results in a large cohort of patients with CIA before the introduction of biologics.

Methods.

A total of 563 consecutive patients with CIA (293 rheumatoid arthritis, 270 spondyloarthritis) and eligible for biologics were prospectively enrolled. Demographic, clinical, and biological data were recorded. Risk factors for LTBI were assessed. All patients underwent a TST, a chest radiograph, and an IGRA test (T-SPOT.TB).

Results.

Agreement between the 2 tests was low (κ = 0.16). The bacillus Calmette-Guerin (BCG) status was significantly associated with discordance between the 2 tests (p = 0.004). The TST positivity rate was 34.8%. Factors associated with a negative TST were female sex (p = 0.02) and immunosuppressive treatment (p = 0.003). The only LTBI risk factor associated with TST positivity was an abnormal chest radiograph (p = 0.02). T-SPOT.TB was positive in 21.7% of patients and indeterminate in 15.6%. Previous active TB and chest radiograph abnormalities were associated with IGRA positivity (p = 0.008 and p = 3.9 × 10−5, respectively). The BCG vaccination was associated with negative IGRA (p = 3 × 10−4). Indeterminate IGRA results were associated with age, C-reactive protein, and immunosuppressive treatment (p = 0.005, 0.007, and 0.004, respectively).

Conclusion.

Our data support the combined use of T-SPOT.TB and TST in patients with CIA before biologics introduction. However, despite these good diagnostic values, indeterminate results may complicate the use of IGRA.

How frequently do tuberculosis screening tests convert in inflammatory bowel disease patients on anti-tumour necrosis factor-alpha? A pilot study

BACKGROUND

Tuberculosis reactivation can lead to severe complications in patients treated with anti-tumour necrosis factor-alpha.

AIM

To assess the usefulness of repeat tuberculosis screening tests in inflammatory bowel disease patients on stable anti-TNF therapy.

METHODS

Cross-sectional study, in patients on prolonged anti-TNF treatment (≥ 12 months) and basal negative screening for latent tuberculosis. Quantiferon(®)-TB Gold In-tube test was performed and then, tuberculin skin test was administered.

RESULTS

74 patients were included, median duration of anti-TNF treatment was 30 months (IQR 19-54); 47 patients on infliximab and 27 on adalimumab; no patient was on glucocorticoids. Previous BCG vaccination was present in 5 cases. After anti-TNF was started, 4 patients suffered from potential tuberculosis exposure and two cases travelled to endemic areas. The cumulative incidence of tuberculin skin test conversion was 2.7% (95% CI 0.3-9.4%, 2/74), and the incidence rate of tuberculin skin test conversion was 0.83% (95% CI 0.1-2.9%) per patient-year of treatment with anti-TNF drugs. All Quantiferon tests but one (a patient with an indeterminate result and a negative tuberculin skin test) were negative.

CONCLUSIONS

The incidence rate of conversion of tuberculosis screening tests among patients on anti-TNF treatment seems to be low and these conversions were diagnosed based on a positive tuberculin skin test and were discordant with Quantiferon testing.

Evaluation of screening methods for identification of patients with chronic rheumatological disease requiring tuberculosis chemoprophylaxis prior to commencement of TNF-α antagonist therapy

BACKGROUND

Patients undergoing tumour necrosis factor (TNF)-α antagonist therapy are at increased risk of latent tuberculosis infection (LTBI) reactivation. The aim of this study was to determine the optimum available screening strategy for identifying patients for tuberculosis (TB) chemoprophylaxis.

METHODS

We conducted a prospective observational study of consecutive adults with chronic rheumatological disease referred for LTBI screening prior to commencement of TNF-α antagonist therapy. All patients included had calculation of TB risk according to age, ethnicity and year of UK entry, as described in the 2005 British Thoracic Society (BTS) guidelines and measurement of tuberculin skin test (TST) and T.Spot.TB.

RESULTS

There were 187 patients included in the study, with 157 patients (84%) taking immunosuppressants. 137 patients would require further risk stratification according to the BTS algorithm, with 110 (80.3%) classified as being at low risk of having LTBI. There were 39 patients (35.5%) who were categorised as low risk but were either TST and/or T.Spot positive and would not have received chemoprophylaxis according to the BTS algorithm. Combination of all three methods (risk stratification and/or positive T.Spot and/or positive TST) identified 66 patients out of 137 who would potentially be offered chemoprophylaxis, which was greater than any single test or two-test combination.

CONCLUSION

Performing both a TST and T.Spot in patients on immunosuppressants prior to commencement of TNF-α antagonist therapy gives an additional yield of potential LTBI compared with use of risk stratification tables alone. Our results suggest that use of all three screening modalities gives the highest yield of patients potentially requiring chemoprophylaxis.

Identification of latent tuberculosis infection in rheumatic patients under consideration for treatment with anti-TNF-α agents

INTRODUCTION

Immunosuppressive therapy with anti-tumour necrosis factor-α (TNF-α) agents in rheumatic patients modulates the immune system and may increase the risk of reactivating infections that are normally maintained in a latent state, such as tuberculosis. The purpose of this study was to analyse the value of QuantiFERON TB Gold In-Tube (QFT IT) and tuberculin skin test (TST) in BCG vaccinated patients with rheumatoid arthritis and ankylosing spondylitis who were qualified to receive TNF-α blockers.

MATERIAL AND METHODS

Ninety patients with rheumatoid arthritis and ankylosing spondylitis were included in the study. The control group consisted of 20 healthy participants. Chest X-ray, TST and QFT IT were carried out in all persons.

RESULTS

In rheumatic patients positive results of QFT IT and TST tests were identified in 15 cases (16.7%) whereas negative results of both tests were detected in 56 cases (62.2%). In the group of examined patients, 11 (12.2%) had QFT IT-/TST+ test results. In patients with QFT IT+/TST- status one active tuberculosis case was detected. In the control group QFT IT positive results were found in 4 cases (20%) and TST positive in 11 cases (55%). Treatment with TNF-α blockers was introduced in 26 rheumatology patients with the following test status: 3 with QFT IT+/TST+; 20 with QFT IT-/TST-; 3 with QFT IT-/TST+.

CONCLUSIONS

In the BCG vaccinated population the QFT IT assay may potentially improve the identification and selection for therapy for latent TB infection before treatment with anti-TNF agents.

Interferon-Gamma Release Assays versus Tuberculin Skin Testing for the Diagnosis of Latent Tuberculosis Infection: An Overview of the Evidence

A profusion of articles have been published on the accuracy and uses of interferon-gamma releasing assays. Here we review the clinical applications, advantages, and limitations of the tuberculin skin test and interferon-gamma release assays and provide an overview of the most recent systematic reviews conducted for different indications for the use of these tests. We conclude that both tests are accurate to detect latent tuberculosis, although interferon-gamma release assays have higher specificity than tuberculin skin testing in BCG-vaccinated populations, particularly if BCG is received after infancy. However, both tests perform poorly to predict risk for progression to active tuberculosis. Interferon-gamma release assays have significant limitations in serial testing because of spontaneous variability and lack of a validated definition of conversion and reversion, making it difficult for clinicians to interpret changes in category (conversions and reversions). So far, the most important clinical evidence, that is, that isoniazid preventive therapy reduces the risk for progression to disease, has been produced only in tuberculin skin test-positive individuals.

Interferon γ assays in the diagnosis of tuberculosis infection in psoriasis patients who are candidates for biologic therapies

Although there is no doubt that biologic agents are an effective alternative for the treatment of moderate and severe psoriasis, anti-tumor necrosis factor α therapy has been associated with reactivation of latent tuberculosis infection. Tuberculin skin testing (TST) is used to diagnose tuberculosis infection but it has low specificity in patients who have received the Mycobacterium bovis BCG vaccine and low sensitivity in patients with altered cell-mediated immunity. In vitro assays based on the detection of interferon γ released by T cells stimulated by specific Mycobacterium tuberculosis antigens have emerged as an option for the diagnosis of tuberculosis infection. The results to date show that they are a viable alternative to TST thanks to their higher specificity and sensitivity. Furthermore, these assays are also proving to have high negative predictive value, meaning that we might be able to use them without TST in the short to medium term.

Interferon γ Assays in the Diagnosis of Tuberculosis Infection in Psoriasis Patients Who Are Candidates for Biologic Therapies

Although there is no doubt that biologic agents are an effective alternative for the treatment of moderate and severe psoriasis, anti-tumor necrosis factor α therapy has been associated with reactivation of latent tuberculosis infection. Tuberculin skin testing (TST) is used to diagnose tuberculosis infection but it has low specificity in patients who have received the Mycobacterium bovis BCG vaccine and low sensitivity in patients with altered cell-mediated immunity. In vitro assays based on the detection of interferon γ released by T cells stimulated by specific Mycobacterium tuberculosis antigens have emerged as an option for the diagnosis of tuberculosis infection. The results to date show that they are a viable alternative to TST thanks to their higher specificity and sensitivity. Furthermore, these assays are also proving to have high negative predictive value, meaning that we might be able to use them without TST in the short to medium term.

Quantiferon-TB Gold in tube assay for the screening of tuberculosis before and during treatment with tumor necrosis factor alpha antagonists

Introduction

The usefulness of interferon-gamma (IFN-γ) release assays for tuberculosis screening before tumor necrosis factor-alpha (TNF-α) antagonists and for monitoring during treatment is a contraversial issue. The aims of this study were to determine whether TNF-α antagonists affect the results of the Quantiferon-TB Gold in-tube assay (QTF); to assess how QTF performs in comparison with the tuberculin skin test (TST) in rheumatoid arthritis (RA) patients who are about to start treatment with TNF-α antagonists, RA patients who are not candidates for treatment with TNF-α antagonists, rheumatology patients with confirmed current or past tuberculosis infection, and healthy controls, and to determine the specificity of the QTF test to differentiate leprosy patients, another group of patients infected with mycobacteria.

Methods

The 38 RA patients who were prescribed TNF-α antagonists, 40 RA patients who were not considered for TNF-α antagonist use, 30 rheumatology patients with a history or new diagnosis of tuberculosis, 23 leprosy patients, and 41 healthy controls were studied. QTF and TST were done on the same day, and both were repeated after a mean of 3.6 ± 0.2 months in patients who used TNF-α antagonists.

Results

Treatment with TNF-α antagonists did not cause a significant change in the QTF or TST positivity rate (34% versus 42%; P = 0.64; and 24% versus 37%; P = 0.22). Patients with leprosy had a trend for a higher mean IFN-γ level (7.3 ± 8.0) and QTF positivity (61%) than did the other groups; however, the difference was not significant (P = 0.09 and P = 0.43).

Conclusions

Treatment with TNF-α antagonists does not seem to affect the QTF test to an appreciable degree. The higher IFN-γ levels in leprosy patients deserves further attention.

Psoriatic disease and tuberculosis nowadays

Psoriasis is a chronic, relapsing and remitting inflammatory skin and joint disease that has a prevalence of 2-3% in the world's population, whereas of 1-2% in Europe. The traditional concept of psoriasis as the "healthy people's" disease has been recently revised because of ever-increasing reports of associations with various pathological conditions (hypertension, Crohn's disease, type II diabetes mellitus, obesity, dyslipidemia, metabolic syndrome, infectious conditions). Particularly, advances in psoriasis therapies have introduced biologic agents. All the tumor necrosis factor-alpha inhibitors are associated with an increased risk of developing active disease in patients with latent tuberculosis infection, because of TNF-α key role against Mycobacterium tuberculosis. For this reason, exclusion of active tuberculosis and treatment of latent tuberculosis infection are clinical imperatives prior to starting this therapy. Moreover active surveillance for a history of untreated or partially treated tuberculosis or latent form has already been shown to be effective in reducing the number of incident tuberculosis cases.

Corticosteroids and immunosuppressive therapy influence the result of QuantiFERON TB Gold testing in inflammatory bowel disease patients

INTRODUCTION

Latent tuberculosis infection is detected by the tuberculin skin test before treating with anti-Tumour-Necrosis factor alpha (anti TNFα) reagents. More accurate are Interferon gamma release assays (IFNγ release assays) to identify patients with latent tuberculosis. Because of a positive control in this assay, it is possible to identify those patients in which a result of tuberculosis testing is not available due to a lack of stimulation capacity of lymphocytes (indeterminate result). Patients suffering from IBD are often treated with immunosuppressive agents, which may influence the results of tuberculosis testing.

AIM

The aim is to investigate the influence of immunosuppressive agents on the outcome of IFNγ-release assay.

METHODS

50 consecutive patients were documented before introducing anti-TNF-treatment in this single centre study between April 2009 and April 2010. Data of INFγ release assay for latent tuberculosis, skin test and laboratory data and current medication were enrolled.

RESULTS

For the period of one year data of 45 consecutive patients was available for statistical analysis. 24 patients out of 45 (corresponding to 53.3%) received at least low doses of corticoid treatment and 27 patients out of 45 (corresponding to 60.0%) received immunosuppressive agents. 13 patients out of 45 (corresponding to 28.9%) had an indeterminate result of the QuantiFERON test. A correlation between the indeterminate result and combination therapy of corticosteroids was found. The concomitant therapy of immunosuppressive agents lead to a lower IFN release but no significance was found.

CONCLUSIONS

Steroid treatment and further combination therapy with immunosuppressive agents lead to a high risk of indeterminate QuantiFERON test.

Comparison of two gamma interferon release assays and tuberculin skin testing for tuberculosis screening in a cohort of patients with rheumatic diseases starting anti-tumor necrosis factor therapy

Gamma interferon release assays (IGRAs) are increasingly used for latent Mycobacterium tuberculosis infection (LTBI) screening in patients with rheumatic diseases starting anti-tumor necrosis factor (anti-TNF) therapies. We compared the performances of two IGRAs, an enzyme-linked immunospot release assay (T-SPOT.TB) and an enzyme-linked immunosorbent assay (QuantiFERON-TB Gold In Tube [QFT-GIT]), to that of tuberculin skin testing (TST) for LTBI screening of 157 consecutive rheumatic patients starting anti-TNF therapies. Among 155 patients with valid results, 58 (37%) were positive by TST, 39 (25%) by T-SPOT.TB assay, and 32 (21%) by QFT-GIT assay. IGRAs were associated more strongly with at least one risk factor for tuberculosis (TB) than TST. Risk factors for a positive assay included chest X-ray findings of old TB (TST), advanced age (both IGRAs), origin from a country with a high TB prevalence, and a positive TST (T-SPOT.TB assay). Steroid use was negatively associated with a positive QFT-GIT assay. The agreement rate between IGRAs was 81% (kappa rate = 0.47), which was much higher than that observed between an IGRA and TST. If positivity by either TST or an IGRA was required for LTBI diagnosis, then the rate of LTBI would have been 46 to 47%, while if an IGRA was performed only for TST-positive patients, the respective rate would have been 11 to 17%. In conclusion, IGRAs appear to correlate better with TB risk than TST and should be included in TB screening of patients starting anti-TNF therapies. In view of the high risk of TB in these patients, a combination of one IGRA and TST is probably more appropriate for LTBI diagnosis.

Prednisolone treatment affects the performance of the QuantiFERON gold in-tube test and the tuberculin skin test in patients with autoimmune disorders screened for latent tuberculosis infection

BACKGROUND

During screening for latent tuberculosis infection (LTBI), before anti-tumor-necrosis-factor-α treatment, most patients are already receiving immunosuppressive therapy. The objective was to evaluate the performance of the QuantiFERON Gold In-Tube (QFT-IT) and the Tuberculin Skin Test (TST).

METHODS

A prospective multicenter study included 248 patients with ulcerative colitis (39), Crohn's disease (54), rheumatoid arthritis (111), and spondylo-arthropathy (44).

RESULTS

QFT-IT was positive in 7/248 (3%), negative in 229 (92%), and indeterminate in 12 (5%). TST was positive in 54/238 (23%) patients. Chest x-ray was suspect for tuberculosis in 5/236 (2%), and 35/167 (21%) had ≥1 risk-factors for infection with Mycobacterium tuberculosis. The main finding was a pronounced negative effect on QFT-IT and TST performance associated with prednisolone treatment. During prednisolone treatment interferon gamma (IFN-γ) response to mitogen stimulation was impaired (median IFN-γ response 4.9 IU/mL; interquartile range [IQR] 0.8 to ≥10.0) compared to patients 1) not receiving corticosteroids (median ≥10.0; IQR 5.0 to ≥10.0; P = 0.0015) or 2) receiving long-acting corticosteroids (median >10.0; IQR 9.7 to >10.0; P = 0.0058). Prednisolone treatment was strongly associated with negative TST, adjusted odds ratio (AOR) 0.22 (0.1-0.8; P = 0.018), and with an increased risk of indeterminate QFT-IT results AOR 16.1 (4.1-63.2; P < 0.001), whereas no negative effect was found for long-acting corticosteroids. Doses of ≥10 mg prednisolone were associated with a 27% risk of indeterminate results. Single use of azathioprine, methotrexate, or 5-aminosalicylate (5-ASA) did not affect the test results.

CONCLUSIONS

Oral prednisolone severely suppressed QFT-IT and TST performance, whereas the long-acting corticosteroids methotrexate, azathioprine, and 5-ASA did not have a similar detrimental effect. Patients should be screened for LTBI with QFT-IT or TST prior to initiation of prednisolone therapy and negative QFT-IT or TST results interpreted with caution in patients treated with any corticosteroid until further data are available.

T-SPOT.TB assay usage in adults and children

The diagnosis and treatment of TB infection is one of the public health priorities. Until recently, diagnosis of TB infection has been based on the tuberculin skin test (TST). However, this is neither 100% sensitive nor specific for the diagnosis of TB infection owing to its many drawbacks. More recently, T-cell-based IFN-γ release assays (IGRAs) have been developed. In this article, we review the clinical performance of one of the IGRAs, T-SPOT.TB assay, for the diagnosis of TB infection in adults and children. We discuss the principle of the assay, its utility in active TB diseases, latent TB infection and the performance of the test in specialized subgroups of patients, such as immunocompromised individuals. When compared with the TST, the T-SPOT.TB assay has better specificity in bacillus Calmette-Guérin-vaccinated individuals, and data suggest that T-SPOT.TB may be more sensitive than the TST. Data in groups at high risk of progression to disease support the idea that T-SPOT.TB performs better than the TST. In addition, application of T-SPOT.TB by using bodily fluids such as cerebrospinal fluid, bronchoalveolar lavage fluid and pleural fluid may offer new diagnostic approaches in extrapulmonary TB disease. Although IGRAs cannot distinguish active TB disease from latent TB infection, these assays perform better than the TST for the detection of TB infection.

TNF alpha antagonist therapy and safety monitoring

OBJECTIVES

To develop and/or update fact sheets about TNFα antagonists treatments, in order to assist physicians in the management of patients with inflammatory joint disease.

METHODS

1. selection by a committee of rheumatology experts of the main topics of interest for which fact sheets were desirable; 2. identification and review of publications relevant to each topic; 3. development and/or update of fact sheets based on three levels of evidence: evidence-based medicine, official recommendations, and expert opinion. The experts were rheumatologists and invited specialists in other fields, and they had extensive experience with the management of chronic inflammatory diseases, such as rheumatoid. They were members of the CRI (Club Rhumatismes et Inflammation), a section of the Société Francaise de Rhumatologie. Each fact sheet was revised by several experts and the overall process was coordinated by three experts.

RESULTS

Several topics of major interest were selected: contraindications of TNFα antagonists treatments, the management of adverse effects and concomitant diseases that may develop during these therapies, and the management of everyday situations such as pregnancy, surgery, and immunizations. After a review of the literature and discussions among experts, a consensus was developed about the content of the fact sheets presented here. These fact sheets focus on several points: 1. in RA and SpA, initiation and monitoring of TNFα antagonists treatments, management of patients with specific past histories, and specific clinical situations such as pregnancy; 2. diseases other than RA, such as juvenile idiopathic arthritis; 3. models of letters for informing the rheumatologist and general practitioner; 4. and patient information.

CONCLUSION

These TNFα antagonists treatments fact sheets built on evidence-based medicine and expert opinion will serve as a practical tool for assisting physicians who manage patients on these therapies. They will be available continuously at www.cri-net.com and updated at appropriate intervals.

Challenges in Diagnosing Latent Tuberculosis Infection in Patients Treated with Tumor Necrosis Factor Antagonists

Reactivation of latent tuberculosis infection (LTBI) is well recognized as an adverse event associated with anti-tumor necrosis factor-α (anti-TNF-α) therapy. The strengths and weaknesses of current techniques for detecting LTBI in patients with chronic inflammatory diseases such as rheumatoid arthritis (RA) and psoriasis have not been fully examined. T cell hyporesponsiveness due to immunosuppression caused by illness or drugs, referred to as anergy, may produce false-negative tuberculin skin test (TST) and interferon-γ release assay (IGRA) results. The literature suggests that anergy may influence screening performance of TST and IGRA tests in candidates for anti-TNF-α therapy. Conversely, the potential for false-positive TST and IGRA results must be considered, as treatment for LTBI may be associated with significant morbidity. This review examines the reliability issues related to LTBI diagnostic testing and provides practical direction to help prevent LTBI reactivation and facilitate successful anti-TNF-α treatment.