Multiple sclerosis is a chronic inflammatory demyelinating disease of the CNS. Although the aetiology of multiple sclerosis is still unknown, it is widely believed that T cells play a central role in its pathogenesis. To identify and characterize disease-relevant T cells, we analysed CD4+ and CD8+ T cells freshly isolated from the CSF and peripheral blood of 36 multiple sclerosis patients for their T-cell receptor variable beta (TCRBV) chain repertoire. In most patients, we found significant overexpression of individual TCRBV chains on CD8+ T cells from CSF compared with peripheral blood. In contrast, only a few multiple sclerosis patients showed differences between the two compartments in TCRBV expression on CD4+ T cells. The overexpression of specific TCRBV chains on CD8+ T cells was found to be stable over several months in selected patients and involved mainly T cells with a memory phenotype. In two patients studied, individual TCRBV chain overexpression was found to be caused by the expansion of T cell populations with identical or highly similar rearranged T-cell receptor beta- and alpha-chain sequences, which were not found among peripheral blood CD8+ T cells. Our findings demonstrate selective enrichment of memory CD8+ T cells in the CSF of multiple sclerosis patients, suggesting a role for these CD8+ T cells in the pathogenesis of multiple sclerosis. Our study provides a basis for future trials to identify disease-associated antigens and disease pathogenesis in multiple sclerosis.

Glutaric aciduria type 1 (GA1), resulting from the genetic deficiency of glutarylCoA dehydrogenase (GDH), is a relatively common cause of acute metabolic brain damage in infants. Encephalopathic crises may be prevented by carnitine supplementation and diet, but diagnosis can be diYcult as some patients do not show the typical excretion of large amounts of glutaric and 3-hydroxyglutaric acids in the urine. We present a rapid and eYcient denaturing gradient gel electrophoresis (DGGE) method for the identification of mutations in the glutaryl-CoA dehydrogenase (GCDH) gene that may be used for the molecular diagnosis of GA1 in a routine setting. Using this technique, we identified mutations on both alleles in 48 patients with confirmed GDH deficiency, while no mutations were detected in other patients with clinical suspicion of GA1 but normal enzyme studies. There was a total of 38 diVerent mutations; 27 mutations were found in single patients only, and 21 mutations have not been previously reported. Fourteen mutations involved hypermutable CpG sites. The commonest GA1 mutation in Europeans is R402W, which accounts for almost 40% of alleles in patients of German origin. GCDH gene haplotypes were determined through the analysis of polymorphic markers in all families, and three CpG mutations were associated with diVerent haplotypes, possibly reflecting independent recurrence. The high sensitivity of the DGGE method allows the rapid and cost eYcient diagnosis of GA1 in instances where enzyme analyses are not available or feasible, despite the marked heterogeneity of the disease.

SummaryWe have previously reported strong evidence for linkage between IBD1 and Crohn's disease (CD) in Australian Crohn's disease families. Three risk alleles for Crohn's disease, (Arg 702 Trp (C/T), Gly 908 Arg (G/C) and 980 fs 981 (-/C), were recently identified in the CARD15/NOD2 gene on chromosome 16, implicating this as the IBD1 locus. Using a novel diagnostic PCR-RFLP, we have examined the frequency of these alleles in 205 multiplex IBD families, 107 sporadic Crohn's disease cases and 409 normal individuals. We demonstrate that the three risk alleles are more frequent in Crohn's disease, than in controls, with allelic frequencies of 0.11, 0.02 and 0.07 respectively. Heterozygosity for individual variants conferred a three-fold increase in risk for Crohn's disease while substantially higher risks were associated with being homozygous or compound heterozygous. Despite a significantly lower population allele frequency for the frameshift mutation than reported by other groups, we see a similar contribution by this allele to the risk of developing Crohn's disease. While the three risk alleles influence susceptibility to Crohn's disease in Australia, we show that these alleles do not fully explain the linkage evidence and suggest that there are very likely additional IBD1 susceptibility alleles yet to be described in Australian CD at the NOD2 locus. We also show a second linkage peak in Australian CD that provides some support for a second disease susceptibility locus on chromosome 16.

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The ACRS PCR test is useful for laboratories that do not have the equipment to perform probe or SYBR Green I based real-time PCR. Furthermore, the tests developed for the determination of FSAP activity and antigen levels are convenient for determining clinical correlations, even for large population studies. The ratio of activity and antigen level of FSAP appears to be a promising and efficient alternative to molecular diagnostic techniques to detect the MRI polymorphism of FSAP.