Clinical features and outcomes of Chinese patients with anti-γ-aminobutyric acid B receptor encephalitis.

Antibodies against γ-aminobutyric acid B (GABAB) receptor are associated with limbic encephalitis (LE). It is estimated that ~1/2 of patients with LE have small-cell lung cancer. The present study analyzed the specific GABAB receptor antibodies in serum and cerebrospinal fluid (CSF) samples of 12 patients. The clinical manifestations, therapy and outcome were retrospectively compared. The median onset age was 65.1 years and all patients presented with new-onset seizures. In total, 11 (91.6%) patients had memory deficits, 7 (58.3%) patients had psychiatric problems and 4 (33.3%) patients had a disturbance of consciousness. Furthermore, lung cancer was detected in 7 patients (58.3%) by CT scan. Lymphocytic pleocytosis and protein concentration elevation in CSF were detected in 3 (25%) and 4 (33.3%) patients, respectively. Furthermore, MRI scan results identified 4 (33.3%) patients with abnormalities in the mesial temporal region. The lung cancer tissues of 3 patients were positively stained for anti-GABAB receptor on immunohistochemistry. All patients received antiepileptic drugs and immunotherapy. In total, 3 patients with lung cancer were subjected to tumor resection. Those patients without cancer exhibited neurological improvement at the follow-up. The present results suggested that seizures and memory deficits were the major manifestations in Chinese patients with anti-GABAB receptor antibodies who were responsive to immunotherapy. The lung cancer tissues from patients with anti-GABAB receptor antibodies were positively stained for anti-GABAB receptor. Collectively, the present results suggested that patients with underlying lung cancer have a relatively poor prognosis.