COMPARATIVE ANALYSIS OF M. TUBERCULOSIS DETECTION BY DIFFERENT HISTOLOGICAL METHODS IN LUNG TISSUE WITH PULMONARY TUBERCULOMA WITH DIFFERENT ACTIVITY OF SPECIFIC INFLAMMATION

Abstract

Relevance. Modern histological diagnostics of tuberculosis with using of histobacterioscopy is based on the application of Ziehl-Neelsen method, fluorescent and immunohistochemical methods. And it is mainly used for extrapulmonary forms of tuberculosis. From a scientific and practical standpoint, it is advisable to use these methods in a combined.
 Objective. To conduct a comparative analysis of the detection of M. tuberculosis and their antigens by various histological methods in pulmonary tissue with tuberculoma at different activities of a specific inflammatory process.
 Materials and methods. The material for the study was 34 cases of resected parts of the lungs with tuberculoma, two groups were formed: the main group – 19 cases with a high degree of activity of specific inflammation; the comparison group – 15 cases with moderately or low activity. Ziehl-Neelsen staining, fluorescent and immunohistochemical methods were applied. The number of infected cells and extracellular bacilli was determined according to the working gradation: rarely (1-5), moderate (6-15), many (more than 16) bacteria in the field of view of the microscope. At the immunohistochemical examination it was determined the type and relative number of cells with clear positive results.
 Results. All methods of histological diagnosis revealed a free located MBT in the necrotic nucleus and capsule of tuberculoma, and in alveolar spaces at a distance. The greatest number of free located mycobacteria was detected with using fluorescent method and immunohistochemical examination. The Ziehl-Neelsen showed a significant predominance of observations of a moderate amount of infected alveolar macrophages in the main group and a small number of infected macrophages in a group with a moderately or low activity of the inflammatory process (p<0,01). At the progression of tuberculosis, a large number of macrophages with a positive staining to MBT antigens (p<0,001) was more often detected. Highest indicators of diagnostic standards are established for fluorescent and immunohistochemical methods.
 Conclusion. A combined histological study provided the most complete data on the presence, localization and distribution in the affected tissue of both whole structures MBTs and their antigens at the different activity of specific inflammation. Immunohistochemical study showed that the accumulation of MBT antigens is observed in different types of macrophages and monocytes cells.