4-13-07 Characteristics of multiple sclerosis in Brazil a multicentric study in a prevalence cohort — South Atlantic project — Phase I

[Multiple sclerosis: clinical and laboratorial correlation]

The clinical and demographic characteristics of 86 Brazilian patients with clinically definite multiple sclerosis (MS) were compared to the cerebrospinal fluid (CSF) findings. The disease course was relapsing-remitting in 71% and chronic progressive in 29% of the cases. The IgG index was increased in 76% in the chronic progressive status and 46% and 49% during the bout and remission, respectively (p < 0.005). Only 36% of the MS patients using corticosteroids had increased IgG index, in comparison to the 64% of the patients without immunosupressive treatment. Oligoclonal IgG bands were detected in the CSF of 77% and 88% of the MS corticosteroids users and non-users, respectively. The quantitative study of intrathecal synthesis of IgG contributes to demonstrate the immunological differences between the two forms of MS, the relapsing-remitting and the chronic progressive. The treatment with corticosteroids decreases quantitatively the intrathecal synthesis of IgG but not the presence of oligoclonal bands.

Multiple sclerosis in Brazil. Analysis of cerebrospinal fluid by standard methods

The demonstration of intrathecal IgG synthesis has been used as an important laboratory parameter to support the diagnosis of multiple sclerosis (MS). The Committee for European Concerted Action for Multiple Sclerosis has recommended a protocol for the assessment of intrathecal IgG synthesis. We applied this methodology to determine the cerebrospinal (CSF) profile of 128 Brazilian patients with MS. We detected hypercytosis lower than 35 cells/mm3 in 97%, protein lower than 80 mg/dl in 99%, normal blood-CSF barrier function in 76%, increased IgG local production around 53% and oligoclonal IgG bands by isoelectric focusing in 85% of the definite MS patients. The diagnostic accuracy of the quantitative analysis was lower than the qualitative. The detection of oligoclonal bands was especially important in the cases of normal quantitative assays of IgG. In addition, we found a lower frequency of inflammatory reaction in CSF in our MS cases, in comparison to some European studies.

DQB1*0602 confers genetic susceptibility to multiple sclerosis in Afro-Brazilians

We studied the distribution of the HLA-DRB1, -DQA1 and -DQB1 alleles in 44 Afro-Brazilian patients with multiple sclerosis and 88 controls. Although no significant differences were found between the patients and controls for the DRB1 and DQA1 alleles, the HLA-DQB1*0602 allele was positively associated with multiple sclerosis (45.0% vs. 17.0%, Pc=0.024, RR=3.31). The positive extended haplotypes for DQB1*0602 were more frequent in patients than controls, although the differences were not statistically significant in any of them. These results in Afro-Brazilians are in line with other studies which have found DQB1*0602 to be associated with the disease in the absence of the DRB1*1501 allele. We therefore think that the association with the disease in this ethnic group is more allelic than haplotypic.