Proliferation index in tuberculous lymphadenitis

Abstract

During the pathogenesis of any granuloma, activated macrophages (AMs) are recruited and expanded under the influence of the migration inhibition factor. The goal of this study was to determine whether AMs then also proliferate by themselves or not. The proliferation index (PI) of AMs in lymph node biopsies from 40 cases of tuberculous lymphadenitis was evaluated by immunohistochemistry using a monoclonal antibody (MIB-1) to Ki-67. The PI was defined as the percentage of AMs with positive nuclear staining. It ranged from 3.6-20.6% (mean = 11.0 ± 4.4) which was slightly lower than that reported in previous studies. Mitotic figures ranged from 0-6 per 500 AMs. Multinucleated giant cells ranged from 0-6.3 cells per low power field and their PI was exclusively 0%. Areas of caseous necrosis ranged from 5-85% of the total area of the tissue section examined (mean = 61.6 ± 19.8). Mitotic figures, multinucleated giant cells, and areas of caseous necrosis lacked a statistically significant relationship to the PI (p < 0.05). In conclusion, AMs in granulomas can proliferate to a limited degree as detected by the mitotic figures and the PI.