Table 3.
Clinical features, response to treatment, and prognosis related to type of antibody and location of antigens
| Neuronal antibodies: Hu, Ma2, CV2/CRMP5, amphiphysin, atypical (intracellular antigens) |
VGKC antibodies (cell membrane antigens) |
Novel neuropil antibodies (cell membrane antigens) |
|
|---|---|---|---|
| Hippocampal specificity of antibodies | No; antibodies react with neurons of any part of the neuraxis | Mild; all patients with similar pattern of antibody reactivity | Intense; different patterns (some with pure limbic reactivity) |
| CSF inflammatory abnormalitiesa | Frequent | Infrequent (normal CSF or with mild abnormalities) | Frequent |
| Intrathecal synthesis of antibodies | Frequent | Infrequent/absent | Frequent |
| Hyponatremia | No (except some patients with SCLC) | Frequent | No |
| Clinical phenotypes other than limbic encephalitis | Several according to type of antibody [66] | Neuromyotonia; Morvan syndrome [38] | Prominent behavioral and psychiatric symptoms and seizures; central hypoventilation may occur [6,7] |
| Brain MRI | Frequent medial temporal lobe FLAIR/T2 hyperintensities (classic findings) | Frequent classic findings | Infrequent classic findings but frequent temporal lobe involvement |
| Tumor association | SCLC, non-SCLC, testicular tumors, thymoma, other | Infrequent: SCLC, thymoma | Frequent: teratoma, thymoma |
| Response to treatment (tumor and/or immunosuppression) | Rare; except for patients with testicular tumors and Ma2 encephalitis | Frequent (corticosteroids, IVIg, plasma exchange) | Frequent (tumor and/or corticosteroids, IVIg, plasma exchange) |
| Clinical course | Progressive until stabilization or death (Hu, CV2/CRMP5); relapses are rare | Relapses may occur and are treatable | Relapses may occur and are treatable |
| Antibody titers | Usually detectable for months or years | Decrease or disappear in months | Decrease or disappear in months |
a
Pleocytosis, increased protein concentration, elevated IgG index, oligoclonal bands.