1) Improving treatment of cryptococcal meningitis. Cryptococcus neoformans is the most common cause of non-viral meningitis in the U.S. and the disease continues to have an attributable mortality of approximately 30% despite therapy. We have recruited approximately 130 patients with both meningoencephalitis and pulmonary disease. The protocol utilizes the latest in immunological and genetic methods and is divided in two parts: 1) to characterize and apply novel therapeutics to the acute phase of the disease to improve outcomes and 2) identify genetic and immunological risk factors involved in susceptibility to the disease during the convalescence phase. 1) In our last project period we identified a new syndrome in cryptococcal infections in CM, a post-infectious inflammatory syndrome, (PIIRS), which results in a dysfunctional activated immune response within the brains of patients after microbiological control of the organism with standard therapies. Immunological profiling identified several biomarkers of PIIRS, such as sCD27, a measure of T-cell activation and sCD21, a marker of B-cell activation. Within the restricted confines of the skull, this excessive immune activity causes the brain to swell and become dysfunctional, resulting in coma and death. In collaboration with NINDS (B. Bielekova, O. Khan and A. Nath) and the neurosurgical service of the NIH clinical center (P. Chittiboina), we utilize corticosteroids and immune suppressants to reduce inflammation and improve outcome. Within the central nervous system, increased inflammation causes increased in brain edema that requires surgical intervention by inserting a set of plastic tubes to divert cerebrospinal fluid out of the brain and reduce pressures. This project period reported the experience of this neurosurgical intervention and the combination of this with corticosteroid therapy, which results in significant improvement over time. The disease can also extend into the peripheral nerves where it can cause a paralyzing arachnoiditis in about 25% of patients with non-HIV-associated cryptococcal meningitis as is also responsive to corticosteroid therapy. We have also validated an additional CSF marker of neuroinflammation, sCD25, using our previous samples, that can be used to monitor patients with PIIRS in clinical practice. 2) Host susceptibility to cryptococcal disease in previously healthy individuals. a) Autoantibody to host cytokines: Previously, in collaboration with S. Browne of LCID, we had identified patients with C. gattii, a related form of Cryptococcus with an autoantibody to the macrophage stimulator granulocyte-monocyte stimulating factor, GM-CSF. We are presently studying the regulatory pathway of GM-CSF signaling and have found that autophagy plays a key role in this process, suggesting novel mechanisms for intervention. b) Genetic Defects: We have currently performed whole exome sequencing on 87 patients with CM disease and reported that a combination of low CD4 count and subtle mutations in NF-kappa B-essential modulator (NEMO) that alone do not result in disease, together were associated with the development of cryptococcal disease. A second patient was also reported who similarly had a low CD4 count as well as low levels of functionally-significant autoantibodies against GMCSF a cytokine involved in macrophage activation. Since many patients with GMCSF autoantibody also do not develop cryptococcal meningitis, these patients may provide examples of how a genetic or autoimmune second hit may push an individual with ICL to become susceptible to CM and may also suggest why many patients with cryptococcal disease do not have a strong family history of the disease more typical of Mendelian-associated diseases.
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