Local synthesis of specific IgG in the cerebrospinal fluid of patients with neurosarcoidosis detected by antigen immunoblotting using Kveim material

The technique of antigen immunoblotting for detection of specific immunoglobulin G (IgG), using Kveim material as antigen, was applied to paired sera and cerebrospinal fluid from 11 patients with definite neurosarcoidosis, 9 patients with definite sarcoidosis and suspected neurosarcoidosis, 22 patients with possible neurosarcoidosis and 16 patients with other neurological disorders, including multiple sclerosis and optic neuritis. Six of the 11 (55%) patients with neurosarcoidosis, none of the 9 patients with definite sarcoidosis and suspected neurosarcoidosis, 5 of the 22 (23%) with possible neurosarcoidosis, and none of the control patients had local synthesis of specific IgG reacting with Kveim material at some stage in the disease. Six of the 8 (75%) patients with definite neurosarcoidosis who had never received steroids or immunosuppressants had local synthesis of Kveim-specific IgG. Local synthesis of Kveim-specific IgG was not found in patients who had received in the past, or were still receiving, immunomodulating agents, and local synthesis was abolished when such treatment was introduced to those patients who had been positive. Those patients whose cerebrospinal fluid showed local synthesis of oligoclonal total IgG were more likely to have local synthesis of Kveim-specific IgG, but not necessarily in an oligoclonal fashion. Immunoblotting, using Kveim material, may thus be a useful adjunct for the investigation of suspected neurosarcoidosis.