Морфологія (Oct 2020)
Fluorescent methods in morphological diagnostics of respiratory tuberculosis in HIV-infected patients
Abstract
Background. Among the spectrum of respiratory diseases in HIV-infected patients, the leading place is taken by tuberculosis (TB). First of all, difficulties in the morphological diagnostics of TB are associated with the smooth over of its typical histological signs under condition of severe immunodeficiency. To objectify the histological conclusion about the presence of tuberculosis lesion in a morphology a number of specific histochemical and fluorescent methods have been developed, which are based on the direct or indirect detection of M. tuberculosis (MBT) in the affected tissues. Objective – to determine the advisability and effectiveness of using of fluorescent methods in the morphological diagnostics of respiratory tuberculosis in HIV-infected patients. Methods. The morphological study included 37 cases. Two methods were used: the traditional fluorescent method (FM) and immunohistochemical study with a polyclonal antibody to M. Tuberculosis with a fluorescent label (FITC). In the study group, the histological conclusions were compared with the final clinical diagnosis and the results of microbiological investigations. The sensitivity, specificity and effectiveness have been established for each of the methods. Results. At hospitalization only in one third of cases, based on the results of clinical and radiological data and laboratory tests, various forms of respiratory TB were suspected. In 26 cases (70,3 %), with traditional staining of tissue samples with hematoxylin and eosin, a histological diagnosis of tuberculosis infection was established. When performing FM, the largest number of positive results was obtained (16 cases, 84,2 %), whereas with FITC, the MBT was detected only in 11 cases (57,9 %). The specificity of the FITC method was 90,5 %, and FM – 84,6 %. The overall efficiency of the parallel application of 2 fluorescent methods was 69,1 %. The coincidence of the results of both methods was noted in 22 cases of 31 (70,9 %). In total, of the using of morphological fluorescent methods, mycobacterium infection in HIV-infected patients was diagnosed in 29 cases (78,4 %), and in 4 cases (10,8 %) mycobacterium infection was established as a background pathology. Conclusion. At the time of hospitalization, in more than half of patients with HIV infection (59,5 %), the results of clinical laboratory and radiological data do not allow determining the true nature of the pathological process. The traditional study of histological samples stained with hematoxylin and eosin made it possible to diagnose mycobacterial infection in 70,3 % of cases. The use of fluorescent methods increased the efficiency of morphological diagnosis of mycobacterial infection by 10,8 %. The fluorescence method showed a high sensitivity (88,0 %), while indicator of specificity was higher with the immunofluorescence method (90,5 %). The overall efficiency of using fluorescent methods for the histological detection of M. tuberculosis was 69,1 %, which indicates the advisability of using these methods in cases of diagnostics mycobacterial infection.
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