Biochemical and histochemical changes pertaining to active and healed cutaneous tuberculosis

BACKGROUND: Fibrosis is one of the major causes of post-treatment morbidity in tuberculosis. The molecular basis of fibrosis in active and healed tuberculous lesions is yet to be fully characterized. OBJECTIVES: To measure the tissue levels of collagen, elastin, fibronectin, transforming growth factor-beta (TGF-beta) and zinc in active and healed lesions of cutaneous tuberculosis. PATIENTS AND METHODS: Biopsy lesions obtained from 17 patients with active cutaneous tuberculosis and 12 patients after a 6-month regimen of antituberculous chemotherapy were examined. Collagen, elastin and zinc were estimated biochemically. In addition, the presence of collagen IV, TGF-beta and fibronectin were determined immunohistochemically. RESULTS: It was found that collagen, elastin, fibronectin and TGF-beta levels were higher in the active lesions. The levels of zinc were similar in both active and healed lesions. Clinically, scar tissue or keloid formation was not seen in any of the healed lesions. CONCLUSIONS: Effective antituberculous chemotherapy will lead to a substantial reduction of fibrosis and the consequent disability that can arise in patients with tuberculosis.