Lepromatous leprosy treated with recombinant interferon gamma: cutaneous histologic changes

Area of Science:

• Immunology
• Dermatology
• Infectious Diseases

Background:

• Leprosy is a chronic infectious disease caused by Mycobacterium leprae.
• Current treatments can be lengthy and face challenges with drug resistance.
• Interferon-gamma is a cytokine with known immunomodulatory and antimicrobial properties.

Purpose of the Study:

• To investigate the histologic effects of recombinant interferon gamma (rIFN-gamma) on cutaneous lesions in active lepromatous leprosy patients.
• To assess the safety and immune response elicited by intradermal rIFN-gamma injections.
• To evaluate changes in Mycobacterium leprae morphology and burden post-treatment.

Main Methods:

• Six patients with active lepromatous leprosy received three daily intradermal injections of 35 micrograms of rIFN-gamma.
• Histologic examination of skin lesions was performed one week after injections.
• Immune cell infiltration, morphology of mononuclear phagocytes, and bacillary appearance were analyzed.

Main Results:

• rIFN-gamma induced significant T-lymphocyte and mononuclear phagocyte infiltration at injection sites.
• Mononuclear phagocytes exhibited large nuclei, non-vacuolated cytoplasm, and reduced lysozyme reactivity.
• While bacillary burden did not significantly decrease, bacilli showed increased granularity, suggesting altered morphology.
• No significant adverse systemic reactions were observed, apart from local induration.

Conclusions:

• Intradermal rIFN-gamma effectively recruits immune cells to leprosy lesions.
• The observed changes in bacilli suggest a potential impact on their viability or structure.
• rIFN-gamma shows promise as an adjunctive therapy for leprosy, warranting further investigation.