Screening for antibodies against the Hu antigen is used to screen patients with possible paraneoplastic syndrome.
The Hu antigen is sometimes referred to as HuD and is also known as ANNA-1 antigen (specifically anti-neuronal nuclear antibodies 1). Hu antigen is present in all neurons in the central and peripheral nervous system and in various types of tumors mainly in the lung. Antibodies against the Hu antigen are present in paraneoplastic subcutaneous sensory neuropathy and in paraneoplastic encephalomyelitis. In this group of patients, 83% also suffer from small cell lung cancer and sometimes other types of cancer (breast cancer, Hodgkin's lymphoma, malignant melanoma, ovarian cancer, testicular cancer, etc.). Small cell lung cancer is occasionally linked to Lambert-Eaton's myasthenic syndrome, which also has autoantibodies against calcium channels (VGCC). Patients with paraneoplastic syndrome often present with neurological symptoms prior to the onset of clinical manifestations due to the tumor.
In the treatment of paraneoplastic syndrome, it is important to find the underlying tumor and to cure it. In general, immunotherapy treatment is more effective against autoantibodies directed against extracellular antigens than for autoantibodies against intracellular antigens.