[Development and use of a domestic test system for diagnosis of tuberculous infection on the basis of quantitative analysis of interferon-gamma induction in whole blood samples in vitro, by using specific recombinant antigens].

A test system was developed to detect tuberculous infection by qualitative analysis of interferon-gamma (IFN-gamma) in the plasma samples after 20-24-hour incubation of whole blood samples in the presence of Mycobacterium tuberculosis (MBT) antigens: tuberculin PPD and a mixture of the MBT-specific recombinant antigens ESAT-6 and CFP-10. The analysis used 3 test tubes each containing 1 ml of heparinized venous blood, one of which served as a control; the other two test tubes were employed to measure antigen-induced IFN-gamma production. Whether this test system might be used to determine primary tuberculous infection was studied in 277 children and adolescents.

[In vitro interferon-gamma induction in whole blood samples is a test for tuberculous infection in children and adolescents].

By applying the interferon-gamma (IFN-gamma) induction technique in the whole blood samples exposed to short-term (22-24-hour) incubation in the presence of Mycobacterium tuberculosis antigens--PPD tuberculin and specific recombinant ESAT-6 lacking in the cells of vaccine BCG and other non-tuberculous mycobacteria, the authors studied the groups of children and adolescents with a negative Mantoux test (n = 31), with postvaccine BCG allergy (n = 40), as well as patients with primary tuberculous infection (n = 84) and those with pulmonary tuberculosis (n = 44). Patients with primary tuberculous infection and a high sensitivity (94%) and a high specificity (97%) may be differentiated from children and adolescents with postvaccinal allergy when the recombinant ESAT-6 antigen and the critical IFN-gamma level (greater than 70 pg/ml) detectable in the plasma samples after incubation with the antigen. It has been also shown that in adolescents with local forms of pulmonary tuberculosis specific IFN-gamma induction may be suppressed in number of cases, which is ascribed to decreased specific immunity.

[Polymerase chain reaction to determine and control drug-resistant Mycobacterium tuberculosis strains].

Real-time polymerase chain reaction was used to develop a one-stage procedure for molecular genetic analysis of Mycobacterium tuberculosis (MBT) DNA in order to determine mutations associated with drug resistance to the antituberculous agents: isoniazid and rifampicin. To analyze the spread of drug-resistance of the causative agent of tuberculosis in Russia, two thousand MBT strains were studied in 24 regions of all the federal districts. Testing 1406 MBT strains isolated by first detected and untreated patients revealed multidrug resistance (MDR) in 21.

[Significance of determination of gamma-interferon in the diagnosis of tuberculous exudative pleurisy].

The pleural fluid concentration of gamma-interferon (gamma-IFN) was studied in 44 patients with exudative pleurisy. The tuberculous nature of exudative pleurisy was established in 25 patients on the basis of X-ray study, a follow-up, microbiological study of pleural exudate specimens, and morphological studies of biopsy specimens obtained at video-assisted thoracoscopy or surgery. The the pleural exudate concentrations of gamma-IFN were over 300 pg/ml (mean 1019 +/- 161 pg/ml) in 19 out of 21 patients with exudative pleuritis in a phase of active inflammation.

[Use of polymerase chain reaction for the diagnosis and evaluation of chemotherapy for pulmonary tuberculosis].

Polymerase chain reaction (PCR) using a new procedure for preparing sputum samples for DNA isolation on the basis of immunomagnetic separation of mycobacteria was employed to examine sputum samples from 141 patients with first diagnosed pulmonary tuberculosis and 510 diagnostic materials from patients with nonspecific lung disease. In 47 patients with pulmonary tuberculosis, sputum bacterial isolation was followed up, by using PCR and conventional microbiological studies during regular, every 6-7-week, examination. The sensitivity of PCR employing the above procedure for preparing the samples averaged 66% versus 48% when a cultural study was applied.