Israel Medical Association Journal

Background: The global spread of tuberculosis necessitates the development of an effective vaccine and new treatment modalities. That requires a better understanding of the differences in regulation of the immune responses to Mycobacterium tuberculosis between individuals who are susceptible or resistant to the infection. Previous immune studies in young Ethiopian immigrants to Israel did not demonstrate anergy to purified protein derivative or a Th2-like cytokine profile.

Objectives: To evaluate the profile of Th1 and Th2 cytokine production in immigrant TB patients, in comparison with asymptomatic control subjects.

Methods: The present study included (part 1): 39 patients with acute TB[1] (group 1), 34 patients with chronic relapsing TB (group 2), 39 Mantoux-positive asymptomatic TB contacts (group 3), and 21 Mantoux-negative asymptomatic controls (group 4). Patients were mainly immigrants from Eastern Europe and Ethiopia. Levels of interferon gamma, interleukin 2 receptor, IL-6[2] and IL-10 were measured in serum and in non-stimulated and PPD[3]-stimulated peripheral blood mononuclear cell culture supernatants, using commercial ELISA kits. In addition (part 2), levels of IFNg[4] and IL-12p40 were evaluated in 31 immigrant Ethiopian patients and 58 contact family members.

Results: Patients with acute disease tended to secrete more cytokines than contacts, and contacts more than chronic patients and controls, without a specific bias. None of the patients showed in vitro anergy. Discriminant probability analysis showed that from the total of 12 available parameters, a cluster of 6 (IFNg-SER[5], IFNg-PPD, IL-2R[6]-SER, IL-10-SER, IL-10-NS[7] and IL-6-PPD) predicted an 84% probability to become a TB contact upon exposure, 71% a chronic TB patient and 61% an acute TB patient. Family-specific patterns of IFNg were demonstrated in the second part of the study.

Conclusions: Firstly, no deficiency in cytokine production was demonstrated in TB patients. Secondly, acute TB patients secreted more cytokines than contacts, and contacts more than unexposed controls. Thus, neither anergy nor a cytokine dysregulation explains susceptibility to acute TB disease in our cohort, although chronic TB patients produced less cytokines than did acute patients and less than asymptomatic contacts. Thirdly, a certain cytokine configuration may predict a trend of susceptibility to acquire, or not acquire, clinical TB. It is presently unclear whether this finding may explain the disease spread in large populations. Finally, the familial association of IFNg secretion levels probably points towards a genetic regulation of the immune response to Mycobacterium tuberculosis. 

Background: During the last decade, Israel, a country with low tuberculosis rates, absorbed some 900,000 new immigrants from TB[1]-endemic countries.

Objectives: To analyze the specific impact of our screening procedures on active TB among children in Israel.

Methods: We conducted a retrospective analysis of epidemiologic and clinical data of all children (aged 0–17) with TB notified to the Ministry of Health between 1990 and 1999.

Results: There were 479 children with TB (male/female ratio 1.36). Most cases (81.8%) were foreign born, predominantly (88.2%) immigrants from Ethiopia and, therefore, huge differences existed in TB incidence rates according to countries of origin. Some 80% were diagnosed within 3 years of arrival, mainly due to active case-finding. Pulmonary TB, with infiltrates on chest X-ray, was found in 49.5%. Extra-pulmonary TB sites were: intra-thoracic lymphadenitis (31.1%), extra-thoracic lymphadenitis (12.5%), bones (3.6%), pleura (1.3%), meninges (1%), and others (1%). Seventy percent had a tuberculin skin test reaction ≥10 mm in size. Two (non-immigrant) children died of TB meningitis.

Conclusions: Most of the pediatric TB cases occurred in recent immigrants and were diagnosed within 3 years of immigration. These data support our policy of active case-finding among new immigrants from Ethiopia and extensive contact evaluation for all TB cases.

Background: One of the measures adopted in Israel since 1959 as part of the tuberculosis control program was screening children aged 12–13 years old. The screening comprised single-step tuberculin skin testing using the Mantoux method.

Objective: To assess the efficacy of tuberculin skin screening for TB[1] in schoolchildren in southwestern Israel as well as the compliance to treatment for latent tuberculosis infection.

Methods: We retrospectively reviewed the records of children in the Ashkelon region who underwent a tuberculin skin test during the period 1995–99.

Results: Of the 28,016 eligible children, 27,232 were tested. In 923 children, mostly from the former USSR and Ethiopia, an induration of 10 mm or more was found. Only 52 Israeli-born children tested positive. Tuberculosis was found in seven children with a positive test, five of whom were from Ethiopia. All children who tested positive were referred to the local TB clinic; only 266 children (28.8%) presented. Only 151 completed the recommended treatment of isoniazid for 6 months. Thus, although screening included most of the targeted children aged 13, only a third of them presented to a TB clinic, of whom only about half completed treatment of latent infection.

Conclusions: Our results indicate that the current policy of screening for latent TB in our region is ineffective in terms of implementation of the recommended treatment. We suggest that only high risk groups be screened, and that a concerted effort be made to implement treatment.

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