Objective Antibodies to glutamic acid decarboxylase (GAD) have been described in a few patients with temporal lobe epilepsies consistent with limbic encephalitis (LE). We studied a cohort of patients with recent‐onset temporal lobe epilepsy caused by LE to test for GAD antibody positivity and response to immunotherapies. Methods Over a period of 3.75 years, 138 patients aged ≥18 years investigated at the Department of Epileptology, University of Bonn, for recent‐onset epilepsy were prospectively collected and studied for cliniconeuroradiological features of LE, autoantibodies, and treatment responses. Results Fifty‐three adult patients fulfilled the criteria for LE: (1) limbic signs and symptoms for ≤5 years and (2) brain MRI revealing mediotemporal encephalitis (T2/fluid attenuated inversion recovery hyperintensity without atrophy). Nine had high‐titer GAD antibodies; 10 had voltage‐gated potassium channel (VGKC) antibodies. Patients with GAD antibodies were younger (median age, 23 years; range, 17‐66 years) (p = 0.003) and presented with seizures only, whereas polymorphic limbic features were more common in the VGKC antibody‐positive group (p < 0.001). None had tumors. Patients with GAD antibodies more frequently had cerebrospinal fluid oligoclonal bands (p = 0.009) and intrathecal secretion of the specific antibody (p = 0.01). Following monthly intravenous methylprednisolone pulses, GAD antibodies remained highly elevated in 6/6 patients, whereas VGKC antibodies normalized in 6/9 patients (p = 0.03). Despite more intense anticonvulsive treatment in the GAD antibody‐positive group (p = 0.01), none of these patients became seizure free, unlike all of the patients with VGKC antibodies (p < 0.001). Interpretation High‐titer GAD antibodies define a form of nonparaneoplastic LE. This is a chronic, nonremitting disorder and should be included in the differential diagnosis of patients with TLE and mediotemporal encephalitis. Therapeutic trials of other immunotherapies should be undertaken. ANN NEUROL 2010;67:470–478

Pancytopenia is regularly encountered in hematology practice, yet there exist few published assessments of the frequencies of various etiologies, and these frequencies exhibit substantial geographic variation. We reviewed bone marrow specimens from pancytopenic adults to determine the most common etiologies and to identify associations with clinical and laboratory findings. Of 132 patients with no history of hematolymphoid neoplasia, no prior bone marrow study for pancytopenia and no recent cytotoxic chemotherapy, 64% had clonal hematopoietic disorders. Most common were myeloid processes: 26% of patients had acute myeloid leukemia, and 17% had myelodysplasia. Less common were lymphoid neoplasms such as non-Hodgkin lymphoma (6%), hairy cell leukemia (5%) and precursor B acute lymphoblastic leukemia (4%). Among non-clonal cases, the most common specific diagnoses were aplastic anemia (5%), megaloblastic anemia (2%) and human immunodeficiency virus (HIV)-related changes (2%). Clonal diagnoses were associated with more severe cytopenias than non-clonal cases. Circulating nucleated erythroid precursors, immature granulocytes and blasts were seen more frequently in clonal cases. Nearly two-thirds of cases of new onset pancytopenia in adults in our North American practice setting have a clonal etiology, with myeloid neoplasms being most common. Blood counts and peripheral smear findings can provide insights into the likelihood of a clonal etiology.