Israel Medical Association Journal

Background: Pulmonary tuberculosis continues to be a major cause of mortality, particularly in developing countries. Despite modern anti-TB[1] treatment, the elderly and immigrants from TB-endemic countries are at risk. Multidrug resistance has yet to be resolved..

Objectives: To determine the mortality rate and predictors of mortality among patients hospitalized with TB in Israel.

Methods: We evaluated the medical records of 461 patients with active pulmonary TB who were hospitalized in the department of respiratory care during the 5 year period 2000–2004. Data included demographic, clinical, laboratory and radiological findings, drug resistance as well as adverse reactions to anti-TB treatment.

Results:| Three main ethno-geographic groups were observed: 253 patients from the former USSR, 130 from Ethiopia, and 54 of Israeli origin (as well as 24 residents of other countries). Of the 461 patients 65 patients (13%) died in hospital. The factors that were best predictors of mortality were older age, ischemic heart disease, cachexia, prior corticosteroid treatment, hypoalbuminemia and pleural effusion (P < 0.005 for all). The ethno-geographic factor and the presence of multidrug-resistant bacteria had no significant effect on mortality in our study group.

Conclusions: The mortality rate in our study was relatively low, and there was no significant difference between the three ethno-geographic groups.

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.