Tissue response in sporotrichosis: light and electron microscopy studies
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Abstract:
On the basis of electron microscopy examination of human tissue affected by sporotrichosis, we have proposed a classification, at the light microscopy level, of fungal cells in tissue. Light and electron microscopy observations clarified the following five points: (1) in sporotrichosis lesions in man, the fungal cells are frequently phagocytized by polymorphonuclear leucocytes (PMNs); (2) phagocytosis of phagocytes by other phagocytes was common, and giant cells phagocytized both fungal cells and PMNs; (3) fungal cells in the tissues of lesions were thought to be highly viable, and their budding was frequently observed within macrophages and giant cells; (4) it was highly probable that PMNs participated in asteroid body formation; (5) few free fungal cells were present in the tissues. We believe that the classification of fungal cells in sporotrichosis tissue into the five categories below is useful for correctly understanding the pathological condition in a sporotrichosis lesion: (1) fungal cells in PMNs, (2) fungal cells in PMNs within macrophages, (3) fungal cells in macrophages, (4) fungal cells in giant cells, and (5) free fungal cells.
Insights
This study classifies fungal cells in sporotrichosis tissue, revealing they are often phagocytized by immune cells like polymorphonuclear leukocytes (PMNs) and macrophages. This classification aids in understanding the pathology of sporotrichosis lesions.
Area of Science:
- Mycology
- Pathology
- Immunology
Background:
- Sporotrichosis is a fungal infection with characteristic tissue manifestations.
- Understanding the morphology and host-pathogen interactions of fungi in tissue is crucial for diagnosis and treatment.
- Previous classifications of fungal elements in sporotrichosis have been limited.
Purpose of the Study:
- To propose a light microscopy-based classification of fungal cells within human sporotrichosis lesions.
- To elucidate the interactions between fungal cells and host immune cells in sporotrichosis.
- To provide a framework for interpreting the pathological significance of fungal elements in tissue.
Main Methods:
- Light microscopy of human sporotrichosis tissue.
- Electron microscopy of human sporotrichosis tissue.
- Observation and categorization of fungal cell morphology and location within host cells.
Main Results:
- Fungal cells are frequently phagocytized by polymorphonuclear leukocytes (PMNs) and macrophages.
- Giant cells were observed phagocytizing both fungal cells and PMNs.
- Budding of viable fungal cells was frequently observed within macrophages and giant cells.
- PMNs likely participate in asteroid body formation.
- Free fungal cells were rarely observed in the tissue.
Conclusions:
- A five-category classification of fungal cells in sporotrichosis tissue is proposed: fungal cells in PMNs, fungal cells in PMNs within macrophages, fungal cells in macrophages, fungal cells in giant cells, and free fungal cells.
- This classification aids in understanding the pathological processes in sporotrichosis lesions.
- The findings highlight the significant role of host immune cells in containing and interacting with the fungus in sporotrichosis.