Onconeuronal and antineuronal antibodies in patients with neoplastic and non-neoplastic pulmonary pathologies and suspected for paraneoplastic neurological syndrome

OBJECTIVE: Onconeuronal antibodies are important diagnostic tool in patients with suspicion of paraneoplastic neurological syndromes (PNS). However, their role in PNS pathophysiology and specificity for particular neurological manifestation remains unclear. The aim of this study was to evaluate onconeuronal and antineuronal antibodies in patients with pulmonary pathologies and suspected for PNS. MATERIALS AND METHODS: Twenty one patients with pulmonary pathologies were selected from the database of 525 consecutive patients with suspicion of PNS. Patients' sera were screened for the presence of onconeuronal and antineuronal antibodies by means of indirect immunofluorescence; the presence was confirmed by Western blotting. Clinical data were obtained from medical records, hospital data base, and questionnaire-based direct telephone contact with patients. RESULTS: Among 21 patients, aged 54 ± 11, with pulmonary pathologies, the most frequent neurological manifestations were neuropathies. Typical PNS included paraneoplastic cerebellar degeneration (PCD) and limbic encephalitis (LE). We found cases with multiple onconeuronal antibodies (anti-Ri and anti-Yo) and coexisting PNS (PCD/LE). Well-defined onconeuronal antibodies were identified in 23.8% of patients. Among antineuronal antibodies, the most frequent were anti-MAG (23.8%). ROC curves analysis revealed high sensitivity of onconeuronal and antineuronal antibodies for typical PNS and lower for pulmonary malignancies. CONCLUSIONS: Tests for antibodies are highly sensitive for the diagnosis of typical paraneoplastic neurological syndromes. Anti-myelin and anti-MAG antibodies are associated with non-neoplastic pulmonary diseases. Patients with well-defined onconeuronal antibodies require careful screening and follow-up, because the PNS diagnosis indicates a high probability of an underlying malignancy.