The study is assembling a well-characterized cohort of patients with presumed chronic Lyme disease and relevant controls. These patients are being extensively evaluated in a cross-sectional study and the neuroborreliosis patients will be followed prospectively after therapy with intravenous ceftriaxone. These studies will yield a prospective database upon which stringent diagnostic criteria can be established and future therapeutic trials can be designed. At this point, 101 patients and controls have been enrolled in the study. Multiple research projects are being developed based on the findings in this population. These include research in diagnostic tests, immunology and clinical manifestations. Examples of progress made in the past year include: In collaboration with Dr. Roland Martin and his group at NINDS, we have performed experiments using a novel methodology to decrypt the antigen specificity of T cell clones isolated from patients with chronic Lyme disease. This new technique employs the application of combinatorial peptide libraries in the positional scan (ps-SCL) format and biometric data analysis. For one of these T cell clones (derived from the cerebrospinal fluid of a patient with chronic neurologic Lyme disease), we were able to deduce the precise Borrelia burgdorferi peptides and autoantigenic peptides that are recognized by it. This is a powerful new tool to investigate what role autoimmune mechanisms play in the development of chronic symptoms associated with Lyme disease as well as to study other infectious and immunologic diseases. This work has been published at Nature Medicine in 1999.In collaboration with Dr. Mario Philipp and his group at Tulane University Medical Center, we evaluated a simpler diagnostic procedure for Lyme borreliosis. This new diagnostic test uses an ELISA format and a small synthetic peptide whose sequence was derived from a lipoprotein of Borrelia burgdorferi. It has a sensitivity of 90% and a specificity of 100%. A manuscript describing the test has been published in the Journal of Clinical Microbiology in 1999.In collaboration with Dr. Stephen Fischer from the Clinical Pathology Department at the Warren Grant Magnuson Clinical Center, a new PCR assay for Borrelia has been developed and is now been clinically applied at the Clinical Center. Using this PCR, we investigated the role of Borrelia in Alzheimer's disease, as there have been reports both in favor and against it. Using this very sensitive PCR assay, which is able to amplify a Borrelia specific DNA target sequence from all B. burgdorferi sensu lato species known to cause disease in humans, we found no evidence of Borrelia in brains of AD patients. This work was published in the Journal of Infectious Diseases in September 2000. In collaboration with Dr. Gill and Frida Stock from the Clinical Pathology Department at the Warren Grant Magnuson Clinical Center, we evaluated a new media reported to be useful in patients with chronic Lyme disease. Our results did not confirm these results and we were unable to culture a reference strain of the bacteria in the new media. These results have been accepted for publication at the Journal of Clinical Microbiology.