Lack of association of increased C-reactive protein and total plasma homocysteine.

Protein and Total Plasma Homocysteine To the Editor: We read with great interest the article on circulating vitamin B6 levels and C-reactive protein (CRP) in cardiovascular disease (CVD) by Friso et al1 showing that low plasma pyridoxal 5 -phosphate (PLP) is associated with higher CRP levels. Total plasma homocysteine (tHcy), a well-known risk factor for CVD,2 represents a major determinant of plasma PLP levels.3 The inverse correlation of CRP and PLP seems to be independent of tHcy levels.1 We tested this hypothesis in 100 patients (59 men and 41 women with a mean age of 63.7 years; range, 31 to 82 years) with CVD and stable angina pectoris who were referred for coronary angiography. Subjects were divided into 2 groups according to normal or elevated CRP values. Group 1 had a CRP 6 mg/L (n 60); group 2 had a CRP 6 mg/L (n 40). Fasting plasma tHcy levels did not differ substantially between the groups (12.5 45 mol/L versus 12.9 3.9 mol/L in groups 1 versus 2; P 0.65). Our data confirm the results from Friso and colleagues,1 as well as observations from others,4 of a lack of association between CRP and tHcy levels. Whereas both elevated levels of CRP and tHcy represent independent risk factors for CVD, the relationship between tHcy, inflammation, and atherosclerosis cannot be explained through a link of tHcy with CRP.5 Other factors, such as vitamin B6 use in the presence of an underlying inflammatory process, could represent a possible link between inflammation and homocysteine metabolism in CVD.