Pulmonary infection with Cryptococcus neoformans in the face of underlying sarcoidosis.

We present a case of limited pulmonary cryptococcal infection following exposure to pigeon excreta in a patient with sarcoidosis. The pathogenicity of Cryptococcus neoformans depends on the interplay between the immune status of the host and the virulence of the infecting strain. It can range from asymptomatic lung colonization in the immunocompetent host to rapidly progressive meningitis in immunocompromised patients. Immunological models of respiratory disease emphasize a distinction between infections associated with immune suppression on the one hand and diseases such as sarcoidosis believed to involve an excessive Th1-mediated immune response on the other. This case exemplifies the complex nature of immunological responses in the lung and highlights the importance of considering the possibility of co-existent fungal infection in individuals with sarcoidosis. Novel immunotherapeutic options for cryptococcal infection are discussed.