In this section
This section deals with clinical conditions associated with neurology which are covered by the Immunology department. For each clinical condition, the relevant immunological tests are listed together with a short explanation of their use.
Myasthenia
Relevant immunological tests:
Impaired neurotransmission in MG is caused by the presence of antibodies to acetylcholine receptor. Associated autoantibodies to skeletal muscle and thyroid microsomes are sometimes also detected.
Although antibodies to acetylcholine receptor (AChR) are present in all patients with Myasthenia Gravis, they are detectable in only 90% of sera tested in the laboratory.
They are particularly difficult to detect in patients with ocular myasthenia, where up to 40% of patients have undetected antibodies.
Antibodies to striated muscle are present in 30% of patients with MG – and 60% of these will also have a thymoma. This test is insufficiently reliable to help in management and is no longer performed.
Motor neuropathies
Relevant immunological tests: Ganglioside Antibodies GM1
Anti-ganglioside GM1 antibodies are present in 80% of patients with pure motor weakness with evidence of multifocal conduction block.
Low titre anti-ganglioside antibodies are present in some sensori-motor neuropathies, SLE, other autoimmune disease and normal controls. Relevant immunological tests: MAG antibodies are detected in 50-75% or patients with IgM paraproteinaemia and peripheral neuropathy. Paraneoplastic neuronal antibodies are detected in a number of neurological conditions where an underlying tumour may be present. Anti-Yo antibodies have been found in paraneoplastic cerebellar degeneration Anti-Hu antibodies have been found in paraneoplastic encephalomyelitis and in sensory neuropathy. Anti-Ri antibodies can be observed in patients with rapidly progressive brainstem tumour. Anti-CV2 antibodies are also found in cerebellar syndromes usually alongside Hu, Yo or Ri. Anti-Amphiphysin antibodies can be found in stiff person syndrome. Anti Ma1 and Ma2 antibodies can be found in limbic encephalitis, brainstem encephalitis and cerebellar ataxia. A negative test result does not exclude the possibility of a paraneoplastic syndrome. (Last reviewed June 2019)