Fungal Infection Susceptibility

Cryptococcus is a fungus that causes infections most commonly in immunocompromised patients, such as those with AIDS and solid organ transplant recipients, particularly renal transplant recipients (1-3). However, approximately one-third of cases fall outside these groups and, overall, 12.9 percent to 17.9 percent have no readily identifiable immune defect (4, 5). The genetic factors, which may predispose to cryptococcosis and the immune response in these patients, have not been extensively studied. 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 various sampling procedures, including saliva, blood, eyebrow hair, CSF, and nail clipping collection. 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, saliva samples, CSF samples, and eyebrow hair samples for research testing. Moreover, with respect to cryptococcosis, patients with isolated non-central nervous system (CNS) disease (e.g., pulmonary) may serve as a subset comparator to those with CNS involvement-a major tissue tropism for Cryptococcus. Genetic and immunologic testing will be performed on all subjects (patients, relatives, and healthy volunteers) to evaluate for possible immunogenetic factors that lead to susceptibility to cryptococcosis. Among the aims of this protocol are to better understand the pathophysiology and genetic factors that lead to defects in host defense and to use modern and evolving methods in molecular and cellular biology to elucidate the pathogenesis of this particular susceptibility. A better understanding of the underlying pathophysiology of immune defects and genetic susceptibility to fungal infections could allow for the rational development of novel therapies for such diseases and to benefit future patients.