Morphological diagnostics of tuberculosis in HIV-­infected patients with thoracic pathology

Abstract

Objective — to determine the diagnostic indicators of various histochemical and immunohistochemical methods for the detection of M. tuberculosis and their antigens in lung tissue in HIV-infected patients.Materials and methods. The morphological study included 37 cases of biopsy, surgical and autopsy material of fragments of the lungs, lymph nodes and parietal pleura in HIV-infected patients. Serial sections were stained with hematoxylin and eosin, method of Ziehl—Neelsen (ZN), the traditional fluorescence method (FM), and immunohistochemical studies, without (IHC) and with a fluorescent label (FITC). The sensitivity, specificity and effectiveness of each method were calculated taking into account the final clinical diagnosis and the results of the microbiological detection of M. tuberculosis.Results and discussion. At the time of hospitalization of HIV-infected patients in 56.8 % of cases the results of clinical, laboratory and radiological data did not allow to determine the nature of the pathological process. According to the results of our study, the highest sensitivity was established for IHC and FM methods — 100.0 and 88.5 % respectively. The ZN method showed the highest specificity index (100.0 %), while the specificity of the FITC and FM method was 75.0 and 60.0 % respectively. The highest diagnostic efficacy indicators were established for IHC and FM methods — 83.8 and 72.2 %. The overall effectiveness of all 4 special histological examination methods was 72.1 %. As a result of an extended histological examination, the main diagnosis of mycobacterial infection was confirmed in 64.8 % cases, including an association with fungal infection in 29.7 % cases. In 10.8 % cases, the diagnosis of mycobacterial infection was withdrawn, and in these cases a fungal infection was diagnosed as the main pulmonary pathology. In 10.8 % cases the presence of mycobacterial infection as a background pathology with other diseases of the chest cavity was proved. The result of a comprehensive histological examination allowed to establish a final clinical diagnosis in 94.6 % cases, and to confirm the presence of mycobacterial infection in 81.1 % cases. In 13.5 % cases there was discrepancy in the histological picture at traditional staining and the results of additional histological methods of staining the preparations.Conclusions. Taking into account the variety of respiratory pathology in HIV-infected patients, including infectious ones, in order to establish a final clinical diagnosis during the diagnostic process, if there is a suspicion of mycobacterial infection, it is advisable to conduct a comprehensive morphological study using various histological methods for diagnosing infections.