Antibodies to Delta/notch-like epidermal growth factor-related receptor in patients with anti-Tr, paraneoplastic cerebellar degeneration, and Hodgkin lymphoma.

IMPORTANCE: The anti-Tr immune response is associated with paraneoplastic cerebellar degeneration and Hodgkin lymphoma (HL). One case series has reported that the Delta/notch-like epidermal growth factor-related receptor (DNER) is the actual target for anti-Tr antibodies, but this result has not been replicated.
OBJECTIVE: To describe a patient with anti-Tr and confirm that DNER is the autoantigen for a series of patients with anti-Tr. DESIGN, SETTING, AND PARTICIPANTS: Observational study and analysis of biological samples for antibodies to DNER at the hospital of the University of Pennsylvania. We examined a cerebrospinal fluid sample from 1 patient with anti-Tr and serum and/or cerebrospinal fluid samples from 5 other patients with anti-Tr. EXPOSURE: Transfection of HEK293T and Hela cells to express DNER coupled to an enhanced green fluorescent protein tag using a plasmid previously used to detect human DNER antibodies.
RESULTS: A man in his 30s with paraneoplastic cerebellar degeneration and anti-Tr underwent treatment with corticosteroids and intravenous immunoglobulin, resulting in clinical improvement before chemotherapy. Despite close oncologic follow-up, a biopsy, positron emission tomography, and computed tomography, he was not diagnosed as having HL until 6 months after symptom onset. The cerebrospinal fluid sample from this patient reacted with cells transfected to express DNER, as did cerebrospinal fluid and/or serum samples from 5 other patients with paraneoplastic cerebellar degeneration, HL, and anti-Tr. Only 4 of the 5 serum samples reacted to permeabilized cells enough to be distinguished from background, but all 5 serum samples convincingly labeled live cells, which had considerably less background. All 6 control serum samples and 1 serum sample from a patient previously diagnosed as having anti-Tr (but without HL or cerebellitis) did not recognize DNER. CONCLUSIONS AND RELEVANCE: This case demonstrates the importance of testing for the anti-Tr immune response in patients with cerebellar degeneration. The strong association of anti-Tr with HL requires careful surveillance for this tumor. We also confirm that DNER is the target antigen of the anti-Tr immune response. Screening for DNER antibodies against living transfected cells may offer an improved signal-to-noise characteristic compared with immunostaining of fixed, permeabilized cells.