Neurologic dengue manifestations associated with intrathecal specific immune response.

BACKGROUND: Dengue infection is caused by a flavivirus, with 4 virus serotypes (types 1 to 4). The serotypes 2 and 3 represent the principal agents related to nervous system involvement. Neurologic involvement occurs in 4%-5% of dengue infection cases. The major mechanisms of the disease may be related to direct viral infection or postinfectious autoimmune process. The detection of intrathecal synthesis of specific antibodies has been used to support neurologic diagnosis as a proof of local reaction. It may be quantitatively calculated by the specific antibody index. OBJECTIVES: To determine if patients with neurologic manifestations associated with dengue produce specific antibodies in the CNS and to determine the antibodies' clinical and pathophysiologic relevance. METHODS: CSF and serum were evaluated for dengue immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies by ELISA and for intrathecal synthesis of IgG antibodies to the dengue virus. Subjects included 10 patients IgM seropositive for dengue virus diagnosed with myelitis, encephalitis, optic neuromyelitis, or Guillain-Barré syndrome. RESULTS: All patients had IgG and IgM antibodies to dengue virus in their sera; 7 were IgM positive and 9 were IgG positive for dengue virus in CSF. Only the 3 patients with myelitis had intrathecal synthesis of specific IgG antibodies. CONCLUSIONS: Intrathecal synthesis of antibodies to dengue virus occurs in the CNS. It may be used as a marker of myelitis associated with dengue, and it seems to be related to the pathogenesis of spinal cord disease due to direct viral invasion.

[Multiple sclerosis: clinical and laboratorial correlation]. / Esclerose múltipla: correlação clínico-laboratorial.

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.