Microtubule ‐associated protein 1B: Novel paraneoplastic biomarker

ObjectiveTo report the identification of microtubule‐associated protein (MAP) 1B as the antigen of the previously described Purkinje cell cytoplasmic antibody type 2 (PCA‐2) antibody, its frequency, and clinical, oncological, and serological associations. MethodsArchival serum or cerebrospinal fluid (CSF) specimens were available from 96 of 118 consecutive PCA‐2‐IgG–seropositive patients identified during 1993–2016. The autoantigen, defined in mouse brain lysate by Western blot and mass spectrometry, was confirmed by dual immunohistochemical staining using commercial antibodies. The major antigenic region was defined by Western blot using recombinant protein fragments. ResultsIgG in 95 of 96 patients’ serum or CSF (but in none of 98 healthy or disease control subjects’ serum specimens) bound to recombinant MAP1B. A minority (17.5%) of patients’ IgG also bound to MAP1A. PCA‐2 was often accompanied by additional neural autoantibody markers of small‐cell carcinoma, including collapsin response‐mediated protein 5 (CRMP5) IgG (26%) or antineuronal nuclear antibody type 1 (ANNA‐1) IgG (also known as anti‐Hu; 13%). Neurological manifestations in 95 patients were (in decreasing frequency): peripheral neuropathy, 53%; cerebellar ataxia, dysmetria, or dysarthria, 38%; and encephalopathy, 27%. Cancer (majority small‐cell lung carcinoma [SCLC]) was detected in 66 of 84 evaluated patients (79%). The MAP1B (PCA‐2) autoantibody detection rate, among approxima...
Source: Annals of Neurology - Category: Neurology Authors: Tags: Research Article Source Type: research