A Case of Sporotrichosis with Numerous Fungal Elements Phagocytized by Polymorphonuclear Leukocytes/Bericht über eine Sporotrichose mit ausgeprägter Phagozytose der Pilzzellen durch Granulozyten

Exogenous Local Hyperthermia at 41℃ Is Effective to Eliminate Mouse Model of Sporotrichosis, Independent of Neutrophil Extracellular Traps Formation

Background

Local hyperthermia is recommended for the treatment of patients with fixed cutaneous sporotrichosis, though the effectiveness and mechanisms of action remain elusive. While neutrophils represent the main inflammatory cells associated with sporotrichosis lesions, the issue of whether hyperthermia is involved with interactions between neutrophils and Sporothrix globosa remains unclear.

Objective

To evaluate the effect of local hyperthermia on sporotrichosis and determine whether local hyperthermia involves effects of neutrophils against Sporothrix.

Methods

For the in vivo study, mice were infected with yeast cells of S. globosa followed by treatment with local hyperthermia. In vitro, an isolated Sporothrix strain was co-cultured with or without neutrophils and subjected under different temperatures. Immunofluorescence was used to assess the formation of neutrophil extracellular trap (NETs) were formed under these different culture conditions and the number of fungi colony forming units were compared.

Results

Hyperthermia was significantly more effective in clearing the lesions in the mouse model, as compared to sham treatment. Neutrophils failed to exert any fungicidal effects against S. globosa in response to hyperthermia. Moreover, NETs were formed after interaction with S. globosa, and the percentage of NETs formed was not significantly different at 41℃ or 37℃.

Conclusion

While hyperthermia could serve as an effective therapy for fixed cutaneous sporotrichosis, this ability does not involve the formation of NETs.

Sporotrichosis masquerading as pyoderma gangrenosum: case report and review of 19 cases of sporotrichosis

We present the case of a 59-year-old woman who had large ulcerations on her right leg that were diagnosed initially as pyoderma gangrenosum and treated with three immunosuppressive agents (cyclosporin, prednisone and azathioprine) for 6 months. Results of a biopsy at 6 months showed numerous cigar-shaped bodies consistent with Sporothrix schenckii; identification was confirmed by tissue culture. A retrospective review was performed for all cases diagnosed as sporotrichosis from tissue culture or biopsy specimens at the Mayo Clinic. Nineteen cases were identified. The present case was the only one in which fungal organisms were visible on histological examination. The present case emphasizes the importance of making a definitive histological diagnosis in unusual ulcer cases or in suspected cases of pyoderma gangrenosum before the initiation of immunosuppressive therapy. The large number of cigar-shaped bodies in the tissue is a rare finding in sporothrix infection and has been reported in only two cases previously.

Comparison between histochemical and immunohistochemical methods for diagnosis of sporotrichosis

AIMS

To compare the efficacy of histochemical and immunohistochemical methods in detecting forms of Sporothrix schenckii in tissue.

METHODS

Thirty five cutaneous biopsy specimens from 27 patients with sporotrichosis were stained by histochemical haematoxylin and eosin, periodic acid Schiff, and Gomori's methenamine silver methods and an immunohistochemical (avidin-biotin complex immunoperoxidase) (ABC) technique associated with a newly produced rabbit polyclonal antibody anti-Sporothrix schenckii.

RESULTS

A total of 29 (83%) cases were positive by the ABC method used in association with anti-Sporothrix schenckii rabbit polyclonal antibodies. Histochemical methods, using silver staining, periodic acid Schiff, and conventional haematoxylin and eosin detected 37%, 23%, and 23% of forms of S schenckii, respectively. The ABC technique was significantly more reliable than periodic acid Schiff and silver staining techniques.

CONCLUSIONS

It is concluded that immunostaining is an easy and rapid method which can efficiently increase the accuracy of the diagnosis of sporotrichosis in human tissue.

Tissue response in sporotrichosis: light and electron microscopy studies

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.

Ultrastructure of asteroid bodies in sporotrichosis

Ultrathin sections were prepared from a paraffin-embedded tissue specimen which had been obtained from a sporotrichosis patient and in which large numbers of asteroid bodies had been observed. Electronmicroscopic examination of the ultrastructure of the asteroid bodies revealed a central fungal cell with peripheral rays. These cells were almost structurally identical with fungal elements found elsewhere than in asteroid bodies; and in the rays, electron-dense granular substance was arranged in layers marked by fissures and material resembling remnants of destroyed host cells. The outermost layer was formed of a granular substance of rather low electron density, surrounded by adherent cell membrane fragments. These findings suggest that an asteroid body might be composed of crystalline products of disintegrated host cells deposited around a fungal cell.