Dr. Koralnik’s basic science and clinical research program is focused ont the pathogenesis of SARS-CoV-2 in patients with long COVID syndrome. In addition, teh Koralnik laboratory is studying the role of the Virome in patients with Neurodegenerative diseases and in patients with HIV/AIDS and substance use disorder.  Dr Koralnik is also studying the polyomavirus JC (JCV), the etiologic agent of Progressive Multifocal Leukoencephalopathy (PML), which occurs in the setting of immunosuppression, including AIDS, hematological malignancies and in organ transplant recipients. He has pioneered the study of the cellular immune response against JCV and has shown that the presence of JCV-specific cytotoxic T lymphocytes (CTL) in the blood and CSF of PML patients is associated with a favorable clinical outcome. His laboratory has defined epitopes of JCV proteins recognized by the CTL, and synthesized MHC class I tetrameric complexes to detect and quantify this cellular immune response. Moreover, he has shown that PML survivors have metabolic changes consistent with an inflammatory reaction in their brain lesions by MR spectroscopy. JCV only infects humans, and there is no animal model of PML. Dr. Koralnik has therefore used the simian polyomavirus SV40 to develop a model of PML in nonhuman primates, and has been able to induce a PML-like disease in immunosuppressed rhesus monkeys. Since there is no specific treatment for JCV, his laboratory is also studying the potential role of immunotherapies for PML, including adoptive T cell therapy, dendritic cell-based therapy and designer T cell therapy. Furthermore, his laboratory has identified JCV variants with specific tropism for granule cell neurons of the cerebellum, cortical pyramidal neurons, and meningeal cells. He has named these novel clinical syndromes, distinct from PML, JCV granule cell neuronopathy (JCV GCN), JCV encephalopathy (JCVE) and JCV meningitis (JCVM).