Clinical Information

Purkinje cell autoantibodies (PCA) are among the antineuronal autoantibodies (ANNA) recognized clinically as markers of a patient's immune response to specific cancers (paraneoplastic autoantibodies).

In 1976, a PCA, defined by indirect immunofluorescence, was described by Dr. John Trotter and colleagues as a serological accompaniment of cerebellar ataxia related to Hodgkin lymphoma. That autoantibody is now known as anti-Tr or PCA-Tr.

PCA-1 (or anti-Yo), first described in 1983, serves as a serological marker for a new or recurrent carcinoma of the ovary, other Mullerian tissue, or breast. PCA-1-positive patients are women in 99% of cases. They usually present with subacute cerebellar degeneration, but 10% have sensory or motor neuropathy.

In 2000, the Mayo Clinic Neuroimmunology Laboratory described and named PCA-2, a new IgG marker of an immune response to small-cell lung carcinoma (SCLC) in patients presenting with a subacute paraneoplastic neurologic disorder.

Other autoantibody markers of immune responses to SCLC include ANNA-1, ANNA-2, ANNA-3, amphiphysin, collapsin response-mediated protein-5 (CRMP-5)-IgG, anti-glial/neuronal nuclear antibody-type 1 (AGNA-1), neuronal calcium channel antibodies (N-type > P/Q-type), ganglionic acetylcholine receptor antibodies, muscle acetylcholine receptor antibodies, neuronal potassium channel antibodies, and striational antibodies.