Pharmacotherapy of cryptococcosis

Endogenous endophthalmitis caused by Cryptococcus neoformans Var. Gattii mimicking choroidal tumor: From positron-emission tomography/computed tomography to histopathology

A 60-year-old immunocompetent female with pneumonia history about 10 years ago suffered from blurred vision overall survival for 3 weeks. Common cold with headache and unintentional body weight loss was also noted recently. Choroidal detachment simulating choroidal tumor was observed in the temporal quadrant. The 18F-fluoro-2-deoxyglucose (FDG) positron-emission tomography/computed tomography (CT) scan showed focal, mild to moderate FDG uptake in the left lateral orbit, and an enhanced lesion was seen on the recent CT scan. The suspicious choroidal tumor became larger in a week. Phacoemulsification, vitrectomy, and retinal biopsies were performed. Histochemical study of the retinal specimens established the diagnosis of endogenous cryptococcal endophthalmitis. Vitreous culture yielded Cryptococcus neoformans var. gattii. Systemic and topical voriconazole eliminated the infection. In the literature, endogenous endophthalmitis caused by C. neoformans var. gattii has not been reported in detail. The key to successful management lies in early diagnosis. If clinical improvement could not be achieved after conventional management and imaging studies have failed to yield a definite diagnosis, retinal biopsy can be considered.

Disseminated cryptococcosis in an immunocompetent child

Cryptococcus is a ubiquitous fungus and is known for causing meningitis and cutaneous infections in immunocompromised individuals. Disseminated cryptococcal infection is very rare and almost always found to occur in immunocompromised individuals especially in persons infected with HIV. This is particularly attributed to its capsulated spores. But there are few reported cases in which it has been found to cause disseminated infections even in immunocompetent individuals. We report a similar case of disseminated cryptococcal infection in an immunocompetent host. Early detection and treatment of disseminated cryptococcosis is essential to reduce morbidity and for better outcome.

Pediatric Cryptococcal Lymphadenitis in the Absence of AIDS: Case Report and Literature Review

We present a rare case of cryptococcal lymphadenitis without immunocompromization in a two-and-a-half-year-old child. He was referred to our center with a fifteen-day history of continued fever. Ultrasound and computed tomography (CT) revealed the enlargement of multiple lymph nodes and lung reticulonodular shadows. Hematological, immunological, and microbiological tests for hepatitis, lymphoma, AIDS, and immunoglobulin deficiencies were negative. Laboratory tests demonstrated elevated erythrocyte sedimentation rate, elevated plasma and urinary ß2-microglobulin (ß2-MG) levels, and elevated C-reactive protein and fibrinogen. Both blood routine and bone marrow aspiration showed elevated eosinophil granulocytes. The diagnosis of cryptococcal lymphadenitis was obtained by excisional biopsy of the cervical lymph nodes. The patient was treated with intravenous amphotericin B and oral flucytosine for five weeks, then with subsequent oral fluconazole for three months. The patient is now doing well. Our case suggests that the diagnosis of cryptococcal lymphadenitis is very difficult without etiology and pathology, especially for a patient with a normal immune system; lymph node biopsy is necessary to diagnose it, and immediate antifungal treatment is necessary to treat it.

Role of sphingomyelin synthase in controlling the antimicrobial activity of neutrophils against Cryptococcus neoformans

The key host cellular pathway(s) necessary to control the infection caused by inhalation of the environmental fungal pathogen Cryptococcus neoformans are still largely unknown. Here we have identified that the sphingolipid pathway in neutrophils is required for them to exert their killing activity on the fungus. In particular, using both pharmacological and genetic approaches, we show that inhibition of sphingomyelin synthase (SMS) activity profoundly impairs the killing ability of neutrophils by preventing the extracellular release of an antifungal factor(s). We next found that inhibition of protein kinase D (PKD), which controls vesicular sorting and secretion and is regulated by diacylglycerol (DAG) produced by SMS, totally blocks the extracellular killing activity of neutrophils against C. neoformans. The expression of SMS genes, SMS activity and the levels of the lipids regulated by SMS (namely sphingomyelin (SM) and DAG) are up-regulated during neutrophil differentiation. Finally, tissue imaging of lungs infected with C. neoformans using matrix-assisted laser desorption-ionization mass spectrometry (MALDI-MS), revealed that specific SM species are associated with neutrophil infiltration at the site of the infection. This study establishes a key role for SMS in the regulation of the killing activity of neutrophils against C. neoformans through a DAG-PKD dependent mechanism, and provides, for the first time, new insights into the protective role of host sphingolipids against a fungal infection.