To compare vitamin B6 levels in rheumatoid arthritis (RA) patients and healthy control subjects.
We measured levels of vitamin B6 in 23 adults with well-controlled RA, and in 23 healthy control subjects matched for age, sex, race, and weight.
Although plasma folate and vitamin B12 concentrations and erythrocyte B6 activity coefficients were similar in the patients and controls, plasma levels of pyridoxal-5'-phosphate (PLP) were lower in the RA patient group (mean +/- SD 46.1 +/- 48.1 versus 69.3 +/- 58.4 nmoles/liter; P < 0.004). In multivariate analyses, PLP was inversely associated with tumor necrosis factor alpha (TNF alpha) production by peripheral blood mononuclear cells (PBMC) (P < 0.001), after adjustment for age, pain score, erythrocyte sedimentation rate, and use of nonsteroidal antiinflammatory drugs.
PLP levels are reduced in patients with RA. This reduction is associated with TNF alpha production by PBMC.