Previous reports including our own have shown low levels of vitamins E and A⁽Reference Ghebremeskel, Williams and Harbige^1, Reference Jimenez-Jimenez²⁾ increased or decreased Zn and Cu⁽Reference Palm and Hallmans^3–Reference Kapaki⁵⁾ and elevated pro-inflammatory cytokines⁽Reference Beck^6–Reference Hollifield, Harbige and Pham-Dinh⁸⁾ in the blood and CSF of multiple sclerosis (MS) patients. The aim of this study was to investigate the relationships between the levels of circulating plasma vitamins E and A, Zn, Cu, interferon-γ (IFNγ), TNFα and IL-6 in MS patients in the remission phase of the disease compared with healthy controls. IFNγ, TNFα and IL-6 were assayed using commercially available paired antibodies (Genzyme Diagnostics Inc., UK) in an ELISA format. Vitamins A and E were extracted in ethanol and determined using HPLC (Philips PU 4100) equipped with a PU 4110 UV/visible detector and C18 reverse phase column. Determination of Cu and Zn was by ICP-MS (Perkin Elmer 5000 ICP-MS). There was no significant difference in the mean plasma levels of vitamin A, Zn, Cu, IFNγ, TNFα and IL-6 between MS patients and healthy controls (Table). There was, however, a significantly (P<0.001) lower plasma vitamin E concentration in patients with MS compared with controls and the mean concentrations of IFNγ, TNFα, IL-6 and copper were elevated compared with healthy controls (Table).

MS, multiple sclerosis patients n 21 aged 22–68 years with relapse-remitting disease (expanded disability status score 2–4.5) TNF-α (n 16), IL-6 (n 8); HC, healthy controls (n 9) aged 25–45, IL-6 (n 4). *P<0.001.

Plasma vitamins A and E were positively correlated (P<0.03, r=0.46) in MS patients and in healthy controls (P<0.04, r=0.6). In MS patients only, a positive correlation between plasma IFNγ and TNFα (P<0.0001, r=0.91) and also between Zn and vitamin A (P<0.07, r=0.4) was observed as well as a negative correlation between Zn and IL-6 (P<0.07, r=0.64). These findings suggest that pro-inflammatory cytokines such as IL-6 may be responsible, in part, for some of the previously observed alterations in circulating nutrients in patients with MS, i.e. Zn and vitamin A. The low plasma vitamin E finding in MS compared with controls is consistent with our earlier observations in MS⁽Reference Ghebremeskel, Williams and Harbige¹⁾ although the present values were higher both in controls (1.7-fold) and MS (1.8-fold) than we previously reported which may indicate an increase in the intake of vitamin E in the general and MS population since the original study. Moreover, vitamin E is an important membrane lipid antioxidant and given the importance of PUFA in MS⁽Reference Harbige and Sharief⁹⁾ it should be further investigated in patients with MS both in remission and relapse phases of the disease and in relation to membrane PUFA.