Spectrum of manifestations of Mycobacterium tuberculosis infection in primates infected with SIV

To characterize the manifestations of coinfection with M. tuberculosis and SIV infection, we studied 12 SIV-infected rhesus monkeys, six of which were infected intrabronchially with a low dose of Mycobacterium tuberculosis H37Rv. In the six coinfected animals, M. tuberculosis antigen-stimulated lung and blood cells produced high concentrations of IFN-gamma but not IL-4 8-16 weeks after infection. Of the three coinfected animals with high levels of plasma viremia, two developed disseminated tuberculosis and the other died of bacterial peritonitis. Of three coinfected animals with moderate levels of plasma viremia, two had no clinical or radiographic evidence of tuberculosis or progressive SIV infection for 6 months after infection. At neuropsy, pulmonary granulomata were observed and acid-fast organisms or M. tuberculosis were present. These clinical, immunologic and pathologic findings are consistent with those in humans with latent tuberculosis infection (LTBI), and suggest that a model of LTBI in SIV-infected primates can be developed. Such a model will permit delineation of the immunologic and microbial factors that characterize LTBI in HIV-infected persons.     

Hormonal shifts in adolescents in the initial period of infection with tuberculosis

In 78 adolescents aged 13-17 years, the functions of the pituitary body, adrenal and thyroid glands and pancreas were examined by means of radioimmunoassay. The controls were represented by 31 subjects with non-infected tuberculosis; in 47 adolescents, tuberculin test was seen to turn positive. The initial period of the tuberculosis infection in adolescents is marked by the following changes: inhibited pituitary function (other than adrenocorticotropic hormone); higher adrenal activity, elevated cortisol levels, altered (predominantly depressed) thyroidal function; and increased pancreas functional activity. The above changes indicate the inhibition of human defense forces and its comparatively high energy consumption. The presence of deviations in the physical development of adolescents, most frequently leading to an excessive weight, and pronounced tuberculin sensitivity aggravate the disturbance of the hormone equilibrium.     

Immunological reactivity in children with Wilms' tumor

Cellular immune reactivity was investigated in 49 newly diagnosed children with Wilms' tumor and compared to age-matched control. The level of total T (T4 degrees) and B lymphocytes was normal while the relative number of T lymphocytes with high affinity receptors for sheep erythrocytes (T29 degrees) was significantly decreased in the patients studied. The lymphocyte response to PHA in vitro was diminished but PHA-induced lymphokine production was not altered. The depression of T29 degrees level and lymphocyte reactivity to PHA was associated with high grade tumor rather than with the clinical stage. Lymphocytes of 42-47% patients reacted with autochthonous and allogeneic KCl tumor extracts in the migration inhibition test and the degree of reactivity was related to the histological differentiation of the tumor.     

Impact of exogenous infection on tuberculosis infection rates in children and adolescents

The impact of exogenous infection on the course of an epidemic process was considered. The spread of tuberculosis infection from an ill patient to children and adolescents within a territorial focus was observed. A mapping study allowed the authors to make a goal-oriented search for patients with tuberculosis, as well as primarily infected children and adolescents.     

Immunological changes in different patient populations with chronic hepatitis C virus infection

AIM: To investigate killer inhibitory and activating receptor expression by natural killer(NK), natural killer T-like(NKT-like) and CD8+ T lymphocytes in patients with chronic hepatitis C virus(HCV) infection with elevated and with persistently normal alanine aminotransferase(PNALT).METHODS: The percentage of peripheral blood Treg cells, KIR2DL3, ILT-2, KIR3DL1, CD160, NKG2 D, NKG2 C expressing NK, T and NKT-like cells, cytokine production and NK cytotoxicity were determined by flow cytometry. Twenty-one patients with chronic HCV infection with elevated alanine aminotransferase, 11 HCV carriers with persistently normal alanine aminotransferase and 15 healthy volunteers were enrolled. RESULTS: No significant differences were observed in the percentage of total T, NK or NKT-like cells between study groups. Comparing the activating and inhibitoryreceptor expression by NK cells obtained from HCV carriers with PNALT and chronic HCV hepatitis patients with elevated alanine aminotransferase, NKG2 D activating receptor expression was the only receptor showing a significant difference. NKG2 D expression of NK cells was significantly lower in patients with elevated alanine aminotransferase. The expression of CD160, NKG2 D and NKG2 C activating receptor by CD8+ T cells were significantly lower in patients with chronic HCV hepatitis than in healthy controls and in HCV carriers with PNALT. Plasma TGF-β1 levels inversely correlated with NKG2 D expression by NK cells. In vitro TGF-β1 treatment inhibited NK cells cytotoxic activity and downregulated NKG2 D expression. CD8+ T cells from HCV carriers with PNALT showed significantly elevated expression of CD160, NKG2 D and NKG2 C activating receptors compared to chronic HCV patients with elevated alanine aminotransferase. Enhanced expression of inhibitory KIR2DL3 receptor, and decreased ILT-2 expression on NK cells were also found in chronic hepatitis C patients compared to healthy controls.CONCLUSION: Our study demonstrated a complex dysregulation of activating and inhibitory receptor expression, such as decreased NKG2 D and CD160 activating receptor expression and increased KIR2DL3 inhibitory receptor expression by NK and cytotoxic T cells and may provide further mechanism contributing to defective cellular immune functions in chronic hepatitis C. Increased NKG2 D receptor expression in HCV patients with persistently normal ALT suggests an important pathway for sustaining NK and CD8 T cell function and a protective role against disease progression.     

Risk factors of primary tuberculosis infection in children and adolescents

Characteristic features of subjects of the VIA registration group (500 children and adolescents) observed by one of the Moscow children's polyclinic from 1983 to 1987 are given. The rate of primary contamination amounted to an average of 0.75% a year. 92.8% of children and adolescents were infected as a result of an unknown contact, while 7.2% of them had contact with relatives suffering from tuberculosis. In case of conversion of tuberculin reactions, hypersensitivity to tuberculin was seen in 12.2% of the patients and a year later in 4.6% the subjects with persistent hyperergy who were then transferred to the VIB registration group. The following risk factors of contaminating and contacting tuberculosis were found: contact with tuberculosis patients; immunization of poor quality or its absence; hypersensitivity to tuberculin; frequent acute respiratory viral infections and chronic diseases; and unfavourable social and living conditions. The number of these factors should be taken into account since with their growth, the rate of hyperergy and risk of developing the disease are higher. More thorough examination and controlled preventive chemotherapy at a sanatorium are required when 2 or more risk factors are available.     

Immunological diagnosis of aspergillosis in patients with pulmonary tuberculosis

The informative value of a number of immunological tests, such as the routine tests of lymphocyte blast cell transformation and indirect hemagglutination, and the original tests of cytotoxic effect and neutrophil damage was studied in diagnosis of aspergillosis. 94 patients with fibro-cavernous tuberculosis and 18 patients with lung aspergillosis along with tuberculosis were examined. It was shown that the tests provided diagnosis of aspergillosis in the tuberculosis patients. The diagnostic efficiency of the tests was studied. The test of neutrophil damage proved to be the most informative. Diagnostic tables for interpretation of the immunological examination results were developed.     

Immunological response of Swiss mice to infection with three different strains of Trypanosoma cruzi

The immunological response of Swiss mice to infection with three strains of Trypanosoma cruzi which differ in their morphobiological, antigenic and isoenzymic characters [Peruvian, 12 SF (S?o Felipe) and Colombian strains] was investigated. The three strains stimulated an elevation of the immunoglobulin fractions IgG2a, IgG2b and IgM during acute infection, as measured by radial immunodiffusion, and an early drop of IgG1 levels. There were low levels of specific antibodies and a negative cutaneous delayed hypersensitivity test to T. cruzi antigens. Cellular reaction of the spleen was evident, with proliferation of lymphocytes and the presence of blastic lymphoid cells in the red and white pulp, and hyperplasia of germinal centres of the lymphoid follicles. Those aspects were consistent with a depletion of the T-cell zone (periarteriolar lymphocyte sheath). Despite these common features, there were clear differences in the onset, intensity and evolution of the splenic cellular reaction and IgG serum levels and in the relationship between these levels and parasitaemia in the mice infected with the three strains of T. cruzi. A positive correlation was seen between high IgG levels and mortality, corresponding to intense exudative tissue lesions, showing that a raised immunoglobulin level was not associated with protection. It is worth observing that the 12 SF strain, which showed the lowest parasitaemic profile and mortality rate, stimulated the greatest elevation of IgG2b during acute infection; and also that IgG2a and IgG2b were the immunoglobulins which showed the greatest increases following infection by all three strains of T. cruzi.