This protocol is designed to examine the immune deficits that predispose to cryptococcosis as well as the clinical and immune responses among previously healthy adults. The patients included will have an unknown predisposing condition and cryptococcosis. Patients will undergo blood, saliva, and tissue sampling. Throughout the study, patients will be provided with standard medical care and will be seen as often as necessary to manage their condition. Patients in whom microbiologic control of the infection has occurred but in whom inflammation is causing neurologic damage may be treated with corticosteroids or other immunosuppressive agents. Genetically related family members of patients will also be screened for clinical, in vitro, immune, and genetic correlates of immune abnormalities. Healthy adult volunteers, as a comparison group, will be enrolled as a source of blood samples for research testing. Moreover, with respect to cryptococcosis, patients with isolated non-CNS disease (e.g., pulmonary) may serve as a subset comparator to those with central nervous system (CNS) involvement a major tissue tropism for Cryptococcus.