Cytotoxic T cells against a peptide of Yo protein in patients with paraneoplastic cerebellar degeneration and anti-Yo antibody.

Anti-Yo antibodies are present in the sera and cerebrospinal fluid of some patients with paraneoplastic cerebellar degeneration (PCD), but there is no evidence that the presence of anti-Yo antibodies causes the Purkinje cell loss seen in PCD patients. We examined the level of cytotoxic T lymphocyte (CTL) activity against a nine-amino acid peptide of the Yo protein using the Human Leukocyte Antigen- (HLA-) based approach called reverse immunogenetics. Mononuclear cells (MNCs) were isolated from the peripheral venous blood and fibroblasts were obtained from the skin of three patients with PCD with anti-Yo antibody. After activating the MNCs of the three patients with the peptide, it showed CTL activity against the Yo protein peptide expressed on autologous fibroblasts. Therefore, CTLs may be involved in the loss of Purkinje cells in PCD.