Tr antibodies

Anti-Tr/DNER antibodies are part of a group of onconeural antibodies that arise in the context of paraneoplastic neurological syndromes (PNS), where the immune system mounts an antitumor response that cross-reacts with neuronal antigens. DNER is a transmembrane protein highly expressed on cerebellar Purkinje cells, playing a role in Notch signaling pathways important for cerebellar development and Purkinje cell-glial interactions. In anti-Tr-associated PCD, the antibody-mediated (and likely T-cell mediated) attack leads to Purkinje cell loss and cerebellar atrophy. This syndrome is strongly and almost exclusively linked to classic Hodgkin lymphoma, often preceding the diagnosis of lymphoma by months, making its detection an important clue to occult malignancy. Clinically, patients present with a subacute (days to weeks) onset of severe, symmetric cerebellar ataxia affecting gait and limbs, dysarthria, nystagmus, and sometimes diplopia. Unlike some other paraneoplastic antibodies (e.g., anti-Yo, anti-Hu), anti-Tr/DNER is relatively specific for the PCD-Hodgkin lymphoma association and less commonly seen with other malignancies. Diagnosis involves antibody testing in serum/CSF via immunohistochemistry or cell-based assays, combined with MRI (often showing cerebellar atrophy in later stages) and PET-CT or lymph node biopsy to identify underlying Hodgkin lymphoma. Treatment focuses on addressing the underlying malignancy (chemotherapy, radiation) plus immunotherapy (IVIG, corticosteroids, plasmapheresis, rituximab), though neurological recovery is often incomplete due to irreversible Purkinje cell loss. This entity is high-yield because it illustrates: (1) the paraneoplastic antibody-tumor association concept tested on boards, (2) the importance of recognizing neurological syndromes as sentinel markers for cancer, and (3) differentiating among paraneoplastic cerebellar syndromes based on antibody type and associated tumor (e.g., anti-Yo with ovarian/breast cancer, anti-Hu with small cell lung cancer, anti-Tr/DNER with Hodgkin lymphoma).