Israel Medical Association Journal

Background: Determining the accuracy of interferon gamma-releasing assays (IGRAs) is difficult due to the lack of a gold standard test for diagnosing latent tuberculosis (LTB). 

Objectives: To analyze the guidelines used for interpreting IGRAs in determining prophylactic treatment management for latent tuberculosis (LTB) in Israel.

Methods: We analyzed the retrospective data of 367 subjects who were referred to our laboratory during the period 2007–2011 for QuantiFERON Test-Gold In Tube (QFT-GIT) tests because of suspected LTB. Demographics and clinical data were retrieved from a questionnaire at enrollment, and 166/367 (45%) were further interviewed by phone in order to complete follow-up information on prophylactic TB treatment. 

Results: The majority of subjects (116/166, 69.9%, P < 0.0001) were spared prophylactic treatment subsequent to QFT-GIT testing. Subjects with negative QFT-GIT and positive tuberculin skin test (TST) results who were BCG-vaccinated had the lowest treatment rates (6/68, 8.8%, P < 0.0001). Most BCG-vaccinated subjects with positive TST and negative QFT-GIT test results received treatment with anti-tumor necrosis factor-alpha (TNFα) (17/19, 89.5%, P = 0.004). We found more negative QFT-GIT test results in subjects who were receiving anti-TNFα or steroid and other immunosuppressive treatment prior to testing (11/11, 100%, P = 0.029; 22/26, 84.6%, P = 0.06; 15/17, 88%, P = 0.06, respectively). 

Conclusions: Deciding on LTB prophylactic treatment in Israel is highly influenced by QFT-GIT test results. QFT-GIT findings contribute to clinical decisions, but their interpretation must also consider the patient’s medical history and clinical characteristics. 

 

Background: The anti-inflammatory effect of montelukast, a leukotriene receptor antagonist, in patients with bronchial asthma is not entirely clear. Basophils can release a variety of mediators, including histamine and leukotriens, which most likely play an active part in the late allergic response.

Objectives: To study the effect of montelukast (10 mg/day) on histamine and cysteinyl leukotriene release from basophils taken from 12 mild atopic asthmatic patients who were given the drug for 4 weeks.

Methods: Basophils were withdrawn at baseline, and after 48 hours, 1 week, and 4 weeks of therapy. Histamine was measured by a radioenzymatic method and leukotrienes by immunologic assay. Histamine and cysLT release was measured spontaneously and following stimulation with interleukin-3 and anti-immunoglobulin E. Spirometry and symptom score were measured before and during treatment.

Results: During the treatment with montelukast there were no significant changes in spontaneous, IL-3 and anti-IgE‑induced histamine release. cysLT release decreased significantly only after 4 weeks of treatment (from 2899 ± 550 pg/ml at baseline to 2225 ± 430 pg/ml at 4 weeks, P = 0.02).

Conclusions: Montelukast does not seem to affect the release of histamine from basophils but mildly inhibits the cysLT release seen after 4 weeks of treatment.