Optic neuritis: prognosis for multiple sclerosis from MRI, CSF, and HLA findings.

We investigated the paraclinical profile of monosymptomatic optic neuritis (ON) and its prognosis for multiple sclerosis (MS). The correct identification of patients with very early MS carrying a high risk for conversion to clinically definite MS is important when new treatments are emerging that hopefully will prevent or at least delay future MS. We conducted a prospective single observer and population-based study of 147 consecutive patients (118 women, 80%) with acute monosymptomatic ON referred from a catchment area of 1.6 million inhabitants between January 1, 1990 and December 31, 1995. Of 116 patients examined with brain MRI, 64 (55%) had three or more high signal lesions, 11 (9%) had one to two high signal lesions, and 41 (35%) had a normal brain MRI. Among 143 patients examined, oligoclonal IgG (OB) bands in CSF only were demonstrated in 103 patients (72%). Of 146 patients analyzed, 68 (47%) carried the DR15,DQ6,Dw2 haplotype. During the study period, 53 patients (36%) developed clinically definite MS. The presence of three or more MS-like MRI lesions as well as the presence of OB were strongly associated with the development of MS (p < 0.001). Also, Dw2 phenotype was related to the development of MS (p = 0.046). MRI and CSF studies in patients with ON give clinically important information regarding the risk for future MS.