Serum proteomic analysis of a pre-symptomatic multiple sclerosis cohort.

BACKGROUND AND PURPOSE: Susceptibility to multiple sclerosis (MS) is determined by environmental and genetic factors, but the cause remains unknown. Changes to the proteome prior to first symptom onset may reflect the underlying pathophysiology of the disease. METHODS: This preliminary study utilized pre-symptomatic and post-symptomatic serum from a sample of 100 incident population-based US military veterans with MS along with 100 matched healthy controls. All samples were obtained from the Department of Defense Serum Repository. Multidimensional protein identification technology tandem mass spectrometry analysis was performed on tryptic peptides of lectin-captured glycosylated serum proteins following albumin/immunoglobulin G depletion. Identified proteins were analyzed with the Ingenuity Pathway Analysis program. RESULTS: The mean intervals between first symptom onset and the collection of pre-symptomatic and post-symptomatic sera were -6.0 and +1.1 years, respectively. Pre-symptomatic proteins from the MS group were differentially regulated compared with both control groups indicating that proteomic changes are detected prior to symptom onset. Pathway analysis showed that proteins involved in the complement and coagulation pathways and lipid transport are significantly altered in the serum of subjects with MS compared with healthy donors. CONCLUSIONS: Compared with healthy controls, differential proteomic changes were noted in the serum of patients with MS that preceded the onset of symptomatic disease. Further work is in progress to confirm or refute these findings.

Antifolate drug resistance and point mutations in Plasmodium falciparum in Kenya.

Due to increased chloroquine resistance, the antifolate/sulpha drug combinations are becoming increasingly important in the chemotherapy of falciparum malaria. However, point mutations in the dihydrofolate reductase gene lead to resistance to the antifolate drugs. We therefore investigated the prevalence of the 6 reported point mutations in this gene among field isolates of Plasmodium falciparum from Kenya, to determine if the mutations correlated with resistance to pyrimethamine and the biguanides cycloguanil and chlorcycloguanil. We used a mutation-specific polymerase chain reaction technique to test for these reported mutations in 21 Kenyan isolates and 4 reference lines. We also amplified and directly sequenced the dihydrofolate reductase coding sequence from these parasites to confirm the results and test for other possible mutations. Of the reported mutations, we found S108N, which is the central mutation of pyrimethamine resistance, and mutations N51I and C59R, which modulate the levels of resistance and may confer decreases in response to cycloguanil that are folate and p-aminobenzoic acid dependent. No isolate possessed the paired point mutations S108T and A16V, or I164L and S108N, which have been associated with cycloguanil resistance in previous studies. These results provided supportive evidence for the combined use of a cycloguanil-class drug (e.g., chlorproguanil) and a sulpha drug (e.g., dapsone) against P.falciparum malaria in Kenya.