Moreover, expanded populations of cdr2-specific cytotoxic T lymphocytes (CTLs) have been detected in the blood and cerebrospinal fluid of PCD patients, suggesting that a CTL-mediated attack on neural cells may serve as the basis of the irreversible neurological impairment seen in patients with PCA-1 positive PCD [37]. This evidence concerns the gene CDR2 and paraneoplastic neurologic syndrome.