Morphological Analyses of Caseous Necrosis Correlated to CD68+ and CD8+ Cells in Biopsies of Tuberculous Pleurisy

Tuberculosis is the most prevalent infectious disease in the world. Granuloma formation and caseous necrosis are hallmarks of M. tuberculosis infection and they represent the protective and inflammatory reactions in the infected tissues. The molecular mechanisms that mediate granuloma necrosis are still not well understood. Objectives: To immunolocalize and correlate the amounts of CD68+ macrophages and CD8+ lymphocytes to caseous necrosis extension in granulomas of tuberculous pleurisy. Methods: The study is a retrospective analysis of 30 pleural biopsies with histopathological diagnosis of chronic granulomatous pleurisy with caseous necrosis. These biopsies were classified according to necrosis intensity as minimal (N1), moderate (N2) and intense (N3). The number of granulomas was also observed and categorized as G1 (1 to 4 granulomas per section), G2 (5 to 8 granulomas per section), and G3 (more than 8 granulomas per section). Results: The means of CD68+ cells counts per mm in N1, N2 and N3 categories of necrosis were 1,287 ± 254, 1086 ±181 and 930 ± 115 respectively. The means for CD8+ cells were 483.7 ± 396, 366.3 ± 43 and 558 ± 53 cells per mm in N1, N2 and N3 respectively. Conclusions: There were no significant statistical correlations between necrosis extension and cell counts. In analyzed biopsies, the number of CD68+ cells was significantly higher than the number of CD8+ cells.