Increased Th1 and Th2 type cytokine production in patients with active tuberculosis.

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 (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 and IL-10 were measured in serum and in non-stimulated and PPD-stimulated peripheral blood mononuclear cell culture supernatants, using commercial ELISA kits. In addition (part 2), levels of IFNgamma 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 (IFNgamma-SER, IFNgamma-PPD, IL-2R-SER, IL-10-SER, IL-10-NS 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 IFNgamma 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 IFNgamma secretion levels probably points towards a genetic regulation of the immune response to Mycobacterium tuberculosis.

Symptomatic hypogammaglobulinemia in infancy and childhood - clinical outcome and in vitro immune responses.

BACKGROUND: Symptomatic hypogammaglobulinemia in infancy and childhood (SHIC), may be an early manifestation of a primary immunodeficiency or a maturational delay in the normal production of immunoglobulins (Ig). We aimed to evaluate the natural course of SHIC and correlate in vitro lymphoproliferative and secretory responses with recovery of immunoglobulin values and clinical resolution. METHODS: Children, older than 1 year of age, referred to our specialist clinic because of recurrent infections and serum immunoglobulin (Ig) levels 2 SD below the mean for age, were followed for a period of 8 years. Patient with any known familial, clinical or laboratory evidence of cellular immunodeficiency or other immunodeficiency syndromes were excluded from this cohort. Evaluation at 6- to 12-months intervals continued up to 1 year after resolution of symptoms. In a subgroup of patients, in vitro lymphocyte proliferation and Ig secretion in response to mitogens was performed. RESULTS: 32 children, 24 (75%) males, 8 (25%) females, mean age 3.4 years fulfilled the inclusion criteria. CLINICAL PRESENTATION: ENT infections 69%, respiratory 81%, diarrhea 12.5%. During follow-up, 17 (53%) normalized serum Ig levels and were diagnosed as transient hypogammaglobulinemia of infancy (THGI). THGI patients did not differ clinically or demographically from non-transient patients, both having a benign clinical outcome. In vitro Ig secretory responses, were lower in hypogammaglobulinemic, compared to normal children and did not normalize concomitantly with serum Ig's in THGI patients. CONCLUSIONS: The majority of children with SHIC in the first decade of life have THGI. Resolution of symptoms as well as normalization of Ig values may be delayed, but overall the clinical outcome is good and the clinical course benign.