Experimental cryptococcosis of the skin

Primary cutaneous cryptococcosis and Cryptococcus neoformans serotype D

We report a healthy, 73-year-old Japanese woman who presented with primary cryptococcosis on the skin of both cheeks. She had initially developed an erythematous, partly ulcerated lesion on the right cheek 2 weeks earlier following an injury. There was no regional lymphadenopathy, and chest X-rays were normal. Histopathological findings showed granulomatous cell infiltration. Periodic acid Schiff staining revealed spores that were identified by the indirect immunoperoxidase staining method as Cryptococcus neoformans. The isolate was identified as C. neoformans var. neoformans serotype D. The skin lesions healed in 1 month without antifungal therapy. A literature review indicates that this serotype tends to produce cutaneous lesions without systemic involvement.

Cutaneous cryptococcal infection without immunodeficiency

A case of cutaneous cryptococcosis (encapsulated strain) in a 67-year-old female, with no evidence of immune suppression (normal cell surface marker analysis and mitogen proliferation studies) and which responded to treatment with oral fluconazole is reported. To date her clinical progress remains satisfactory after 12 months of follow-up.

Cutaneous cryptococcosis in athymic and beige-athymic mice

The dermotropism of Cryptococcus neoformans SLHA in congenitally athymic (nu/nu) and doubly immunodeficient beige-athymic (bg/bg-nu/nu) mice is described. Both bg/bg-nu/nu and nu/nu mice developed cutaneous cryptococcosis within 7 to 12 days following intravenous challenge with 10(4) encapsulated yeast cells. Macroscopically, cutaneous lesions appeared as small subcutaneous nodules without ulceration. Cryptococcal skin lesions were observed primarily on the flank of nu/nu mice, whereas skin lesions in bg/bg-nu/nu mice were distributed over the trunk, abdomen, and face. While bg/bg-nu/nu mice had four times as many macroscopic skin lesions as nu/nu mice on day 14 after intravenous challenge, the skin lesions in nu/nu mice were larger. Histopathology revealed large foci of encapsulated yeasts extending from the basement membrane of the epidermis through the dermis to the underlying musculature. Yeasts in these lesions evoked a minimal inflammatory response that consisted primarily of macrophages. Interestingly, yeast cells appeared to be degrading collagen bundles located in the dermis. The dermotropic strain used in this study produced gelatinase and other proteases in vitro. These results indicate that C. neoformans can be dermotropic in a T-cell-deficient host and that proteases may be a virulence factor(s).

In vivo and in vitro studies with an atypical, rhinotropic isolate of Cryptococcus neoformans

An atypical isolate of Cryptococcus neoformans was investigated because of its consistent and reproducible production of gross nasal pathology following i.v. injection in Swiss albino mice. Dose response to graded concentrations ranging from 1 X 10(2)-1 X 10(7) cells/mouse yielded an LD50 of 1.4 X 10(3) cells/mouse for the atypical rhinotropic strain H140 which was significantly less virulent (p less than 0.01) than our reference strain of Cryptococcus neoformans. There was no significant difference in mortality following the injection of in vitro vs. in vivo passed inoculum. As early as two weeks after inoculation, this strain produced gross nasal enlargement to approximately 2-3 X normal dimensions with granulomatous and ulcerated lesions. The LD60 resulted in the greatest percentage of nasal involvement (85%). C. neoformans was demonstrated by culture and histopathology in the noses, brains, lungs, livers and kidneys. A temperature selection was indicated by findings of a lower temperature minimum for subcultures isolated from the noses relative to those isolated from the brain, and by the fact that the most densely populated organs following intraperitoneal injection were the testes. This route of inoculation resulted in cutaneous nasal involvement in a manner analogous to that following i.v. injection. The atypical isolate was unable to assimilate trehalose or raffinose but otherwise was entirely consistent with identification as C. neoformans and produced characteristic CNS and general organ system disease in addition to the rhinotropic cutaneous manifestations. The model characterized here in normal mice may be of value in studies of fungal dermotropism.

Primary cutaneous cryptococcosis

A 7-year-old boy, without apparent underlying disease, but with a non-specific failure in his cellular immunity, developed a cutaneous lesion on the left retroauricular area with spontaneous healing. Mycologic study revealed Cryptococcus neoformans, a capsule deficient strain, as the etiologic agent.

Effects of stimulation and suppression of cell-mediated immunity on experimental cryptococcosis

A model of cryptococcosis was developed using intraperitoneal infections of guinea pigs. This model shared characteristics with cryptococcosis in humans and was used to study the effects of immunosuppression and immunostimulation on cryptococcosis. Female guniea pigs survived longer than males; perphaps this was related to a greater capacity of their monocytes to kill cryptococci. A brief course of cortisone shortened survival of females and resulted in depressed immune and inflammatory responses, which persisted long after cortisone was stopped. Stimulation of the immune response by treatment with cryptococci in Freund complete adjuvant improved survival in males. Preliminary studies indicated the usefulness of this model for the study of other potential immunostimulants, including immune lymphocytes, transfer factor prepared from immune lymphocytes, and levamisole. Overall, long-term survivors appeared to clear disseminated cryptococci from extraperitoneal sites including brain, rather than prevent dissemination of cryptococci from the peritoneal cavity. The quantity of the inflammatory response in infectious foci, rather than the ability of individual leukocytes to kill crytococci, may have determined the outcome of most infections.