Immuneglobulins isotypes (IgG and IgM) for myelin basic protein (MBP), cerebrosides (CER), gangliosides (GANG) and cardiolipin (CARD) were detected in the cerebrospinal fluid (CSF) from 33 patients with multiple sclerosis (MS), 18 with Guillain-Barré syndrome (GBS) and 30 with systemic lupus erythematosus (SLE). In MS patients occurred positive and significant levels of IgG-MBP in 51,5% (p<0.05) and IgM-MBP in only 18.2%, IgG-CARD in 46.2%, as long as CER and GANG were detected in almost 20%. From serum samples of MS patients 20.6% presented IgG-MBP, while 53% showed positive levels foi IgM-MBP. The CSF analysis of patients with GBS showed that 56.3% revealed IgG-MBP (p<0.05), 53% for IgM-MBP. 3&.5% for IgG-CER and 23% for IgM-CER, while 50% of patients had IgG-CARD, as long -as 31% also had IgG-GANG. The serum evaluation from 14 patients showed that 18.8% had positive concentrations of IgG-MBP and 56.3% presented IgM-MBP (p<0.05) Except for 50% of patients with SLE who presented positive CSF levels of IgG-CARD. only 24.1% had positive levels of IgG-MBP. We believe that the presence of antiphosphohoid antibodies in CSF of the above mentioned diseases occurred as immune epiphenomena, but their appearance would permit the maintenance of and perpetuate the immune event.