Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Before Beginning Anti-TNF, a Better Targeted Screening and a Twice Decrease Frequency of Latent Tuberculosis (TB) with IFN gamma Release Assays (IGRA) Compared with Tuberculin Skin Test. Results in 396 Patients from the ETAT Study.

Mariette3,  Xavier, Baron3,  Gabriel, Liote3,  Frédéric, Goupille4,  Philippe, Flipo1,  René-Marc, Combe2,  Bernard, Tubach3,  Florence

Lille University
Montpellier University
Paris University
Tours University

Background:

In spite of screening for latent tuberculosis (TB) with tuberculin skin test (TST), reactivation of TB remains a non rare severe complication in patients treated with TNF blockers, mainly with monoclonal antibodies. Great hope came from a more efficient screening of latent TB with specific IFN gamma release assays (IGRA).

Objective:

To compare TST and 2 IGRA in a large cohort of patients with different immune mediated inflammatory diseases (IMID) before introduction of anti-TNF.

Methods:

396 patients with IMID were screened for latent TB with TST and with 2 IGRA, Quantiferon Gold and T-Spot TB, before beginning anti-TNF. 126 patients (32%) had rheumatoid arthritis, 178 (45%) had spondyloarthritis and 92 (23%) had Crohn's disease. 238 patients (60%) received an immunosuppressive treatment and 144 (36%) received steroids.

Results:

138 patients (35%) had positive skin test (> 5mm) and 66 (17%) had positive IGRA (either Quantiferon Gold or T-Spot TB), p< 0.0001. Interestingly, 122 patients (31%) had discordant results between TST and IGRA, 97 (25%) with positive TST and negative IGRA and 25 (6%) with negative TST but positive IGRA. The discordant results in the different diseases are indicated in the table.

Proportion of positive results was higher with T-Spot TB than with Quantiferon Gold: 59/396 (15%) versus 39/396 (10%), p= 0.0006.Concordance between the 2 IGRA tests was good: 91%[88–94], kappa= 0.61 [0.49–0.73].

In multivariate analysis, the factors influencing positivity of IGRA (one or the other) were to be born in a TB endemic area (OR=2.9 [1.5–5.7]) and not to be vaccinated with BCG (OR=3.7 [1.3–10.8]).

The number of indeterminate results was greater with T-Spot TB than with Quantiferon Gold TB: 29/396 (7.3%) versus 11/396 (2.8%), p=0.002. Among the 29 indeterminate tests with TsSpot TB, 25 were negative with Quantiferon Gold, 3 were positive and 1 was indeterminate. Among the 11 indeterminate tests with Quantiferon Gold, 8 were negative with TsSpot TB, 0 were positive and 3 were indeterminate. No factor influences an indeterminate result of IGRA, and in particular neither steroid use nor immunosuppressant use.

All the patients were treated with antibiotics depending of the IGRA tests (1 or the other). No patient developed TB with 1 year of follow-up.

Conclusion:

In this large series of almost 400 patients assessed for latent TB before anti-TNF, IGRA are positive in twice less cases than TST and 31% of the patients had discordant results between TST and IGRA, ¾ with positive TST and negative IGRA and ¼ with negative TST and positive IGRA. Using IGRA for screening of latent TB seems more effective than TST for better targeting the population at risk of TB with anti-TNF treatment but the sensitivity and the specificity of each of the tests will have to be assessed in the sub-group of patients with certain latent TB on clinico-radiological arguments independently of the results of the tests.

  IGRA + in all patients (n = 396)IGRA + in RA patients (n = 126)IGRA + in SpA patients (n = 178)IGRA + in CD patients (n = 92)
  NoYesTotNoYesTotNoYesTotNoYesTot
TST + (> 5 mm)No233252587913928579269574
 Yes9741138 (34.9%)241034 (27.0%)582886 (48.3%)15318 (19.6%)
 Tot33066 (16.7%)39610323 (18.3%)12614335 (19.7%)178848 (8.7%)92
P (IGRA + vs TST+ <0.00010.07<0.00010.03

To cite this abstract, please use the following information:
Mariette, Xavier, Baron, Gabriel, Liote, Frédéric, Goupille, Philippe, Flipo, René-Marc, Combe, Bernard, et al; Before Beginning Anti-TNF, a Better Targeted Screening and a Twice Decrease Frequency of Latent Tuberculosis (TB) with IFN gamma Release Assays (IGRA) Compared with Tuberculin Skin Test. Results in 396 Patients from the ETAT Study. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :376
DOI: 10.1002/art.28145

Abstract Supplement

Meeting Menu

2010 ACR/ARHP