Demographic, tumour, clinical, treatment response and prognosis in cell surface antibody-mediated syndromes where an underlying tumour is often detected in a minority of cases
| Antibody (alternative names) | Demographics and tumour frequency | Main associated tumour types | Predominant associated syndromes | IT responsive? | Life expectancy |
| NMDAR antibodies 7 45–48 | ~80% female, median age 27, ~30% with teratoma | Mainly ovarian teratoma, especially in women aged <45 | NMDAR-Ab-E: psychiatric features, seizures, movement disorder, dysautonomia | Yes, good outcomes with early (<40 days) IT (steroids+at least one other immune treatment) and early oophorectomy, in teratoma cases | In a large cohort, of which 94% was treated with IT and/or tumour removal, ~5% mortality, almost all patients had an mRS score of 5 before death. |
| GABAA/B receptor antibodies: GABAA 81 | Male=female, median age ~40 (but can affect paediatric population), tumour in 60% of adults (10% children) | Thymoma | Acute encephalitis with prominent seizures, including status epilepticus and epilepsia partialis continua | Partial or complete (~30%) recovery in ~85% of patients undergoing IT | In same cohort death in ~15%, 2/3 had status epilepticus and 1/3 had sepsis |
| GABAB 9 77 79 | Male ~80% and median age mid-60s in paraneoplastic cases (tumour in ~50% of GABAB, often with additional onconeuronal positivities) | SCLC | Limbic encephalitis predominant in paraneoplastic patients | Response of neurological syndrome to IT in up to ~90% of treated paraneoplastic patients, often partial | Median survival of ~15 months, death in patients with tumour due to cancer progression or chemotherapy complications (death rare in patients without tumour) |
| AMPA receptor antibodies8 | Median age ~55, women ~70%, tumour in ~50% | Lung, breast, thymus, ovarian | Encephalitis, often severe and acute Confusion and memory deficits prominent, may present with or without seizures | Median mRS score of 2 in mainly IT-treated patients; worse outcomes reported in those with fulminant encephalitis | Death occurred in ~50% of the fulminant encephalitis cases but was rare with other presentations. |
| CASPR2 antibodies41 | Median age 60s, men ~90%, tumour in up to 40% (Morvan’s syndrome) | Thymoma | Morvan’s syndrome predominant in the paraneoplastic group. Other presentations include limbic encephalitis, cerebellar syndrome, isolated neuromyotonia/myokymia, painful peripheral nerve syndrome | ~50% of patients with tumour had a neurological improvement in mRS score with IT. | ~50% death rate among IT-treated patients with Morvan’s syndrome and tumour |
AMPA, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid; CASPR2, contactin-associated protein-like 2; GABAA/B, γ-amino butyric acid (alpha/beta subunit); IT, immunotherapy; mRS, modified Rankin Scale; NMDAR, N-methyl-D-aspartate receptor; NMDAR-Ab-E, NMDAR-antibody encephalitis; SCLC, small cell lung cancer.