engleski

Immunodiagnosis of paraneoplastic syndrome

Paraneoplastic neurological syndromes (PNS) occur very rarely in patients with cancer provided that they are not caused by invasion of the tumor or its metastases, or neurotoxicity of the standard cancer treatments such as a radiotherapy and chemotherapy. Immunologic factors appear important in the pathogenesis of PNS because anti-neuronal autoantibodies and T-cell responses against nervous system antigens have been defined for many of these disorders. Immunologic response is elicited by ectopic expression of neuronal antigens by the tumor. The clinical presentation of neurological symptoms is caused by autoimmune reactions directed against antigens common to both the cancer and the nervous system, designated as "onconeuronal" antigens. Paraneplastic neurological syndrome can affect any part of the central and peripheral nervous system. In recent years, a few specific antibodies directed against different "onconeuronal" antigens have been identified and molecularly characterized by serologic screening of complementary DNA(cDNA) expression libraries of patients with PNS. In routine laboratory immunodiagnosis, these autoantibodies are detected by indirect immunofluorescence (IIF) on primate tissue preparations of cerebellum, peripheral nerve and fetal intestine (screening test) and by Western blot analysis with specific recombinant antigens (confirmation test). Diagnostic paraneoplastic autoantibodies directed against "onconeuronal" antigens recognize neuronal nuclear proteins (anti-Hu-ANNA-1 ; anti-Ri-NOVA1, NOVA2-ANNA-2, anti-MA2) and neuronal cytoplasmic proteins (anti-Yo-CDR2-PCA-1, anti-Tr-PCA-Tr, anti-CV2-CRMP5, anti-amphiphysin). All these paraneoplastic autoantibodies are included in diagnostic criteria in reaching decision between "definite" and only "possible" paraneoplastic neurological syndromes. One or more positive neuronal nuclear or neuronal cytoplasmic autoantibodies observed in patients with paraneoplastic disorders are connected with specific neurological syndrom and patient s neoplasm.

paraneoplastic syndrome; "onconeuronal" antibodies; antigen Hu; Yo; Ri

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