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Ultrastructure of the dermal microvasculature in leprosy
Abstract:
Infection with M. leprae may lead to the presence of the organism within the dermal vascular endothelium, a phenomenon most pronounced in lepromatous leprosy. In order to study the ultrastructural features of the dermal microvasculature in leprosy, biopsies from 18 patients with lepromatous (14), borderline lepromatous (1) and borderline tuberculoid (3) leprosy were examined. Four patients with Lucio's phenomenon and four with erythema nodosum leprosum were included. The ultrastructural changes in the dermal microvasculature included endothelial swelling and hypertrophy, increased endothelial and pericytic cytoplasmic processes, and pronounced basal lamina reduplication. Occasional large, pale, endothelial cells with widely dispersed organelles were encountered. Phagocytized, membrane-bound intraendothelial organisms were found, similar in appearance to those within dermal macrophages. The predominantly perivascular dermal inflammatory infiltrate consisted of lymphocytes, macrophages and mast cells. The observed ultrastructural changes in the dermal microvasculature are similar to those previously described in the endoneurial vessels. While reflecting nonspecific responses of the dermal microvasculature in chronic inflammation, the findings support a possible role of the small dermal vessels in the chronic nature of the host's response to infection with M. leprae.
Insights
Leprosy infection can involve the dermal vascular endothelium, particularly in lepromatous leprosy. Ultrastructural analysis revealed microvascular changes suggesting a role for small dermal vessels in the chronic inflammatory response to Mycobacterium leprae.
Area of Science:
- Dermatology
- Infectious Diseases
- Pathology
Background:
- Mycobacterium leprae infection can affect dermal vascular endothelium.
- This phenomenon is most prominent in lepromatous leprosy.
- Understanding microvascular changes is crucial for leprosy research.
Purpose of the Study:
- To investigate the ultrastructural features of dermal microvasculature in leprosy patients.
- To compare changes in various leprosy types and associated conditions.
Main Methods:
- Biopsies from 18 leprosy patients (lepromatous, borderline lepromatous, borderline tuberculoid) were examined.
- Included patients with Lucio's phenomenon and erythema nodosum leprosum.
- Utilized electron microscopy to analyze ultrastructural changes.
Main Results:
- Observed endothelial swelling, hypertrophy, and increased cytoplasmic processes.
- Noted basal lamina reduplication and occasional large, pale endothelial cells.
- Found phagocytized Mycobacterium leprae within endothelial cells and inflammatory infiltrates.
Conclusions:
- Dermal microvascular changes in leprosy are similar to those in endoneurial vessels.
- These changes reflect nonspecific responses to chronic inflammation.
- Small dermal vessels may play a role in the chronic host response to Mycobacterium leprae infection.