[A case of human immunodeficiency virus infection with cerebellar ataxia that suggested by an association with autoimmunity].

We report a case of human immunodeficiency virus (HIV) infection that showed subacute progressive cerebellar ataxia without HIV encephalopathy or other encephalopathies, including progressive multifocal leukoencephalopathy or encephalitis of other human herpes virus (HHV) infections. A 43-year-old man exhibited unsteady gait. Neurological examination disclosed ataxia of the trunk and lower extremities. Personality change and dementia were absent. Magnetic resonance imaging did not reveal any abnormal finding, including of the cerebellum. The serum HIV-1-RNA was 1.2 × 10(5) copies/ml, and the absolute CD4 lymphocyte count was 141 cells/ml. Remarkably, the serum anti-Yo antibody, as an anti-cerebellar antibody of paraneoplastic syndrome, and anti-gliadin antibody, associated with celiac disease or gluten ataxia, were positive. The cerebrospinal fluid (CSF) immunoglobulin G index was 1.2 (< 0.8), and oligoclonal bands were present. PCR of the CSF was negative for HIV, JC virus, other HHVs, and mycosis. Previous reports presented HIV-infected patients with concurrent autoimmune diseases such as systemic lupus erythematosus, anti-phospholipid syndrome, autoimmune thrombocytopenia, vasculitis, polymyositis and dermatomyositis, sarcoidosis, Graves' disease, and hepatic diseases. These might have been present in patients with a CD4 T lymphocyte count of more than 200 cells/ml. On the other hand, paraneoplastic syndrome, gluten ataxia, cerebellar ataxia associated with anti-glutamic acid decarboxylase antibody, and Hashimoto's encephalopathy might manifest as autoimmune cerebellar ataxia. As regards the association of HIV infection and autoimmune cerebellar ataxia, a previous report suggested that anti-gliadin antibody was detected in about 30% of HIV-infected children, though there is no reference to an association with cerebellar ataxia. Moreover, to our knowledge, detection of anti-Yo antibody in an HIV-infected patient with cerebellar ataxia has not been reported. These findings suggest that, although it is extremely rare, clinicians need to consider HIV infection in a patient exhibiting autoimmune cerebellar ataxia.