Apolipoprotein-defined lipoprotein abnormalities in rheumatoid arthritis patients and their potential impact on cardiovascular disease.

OBJECTIVES: The aim of this study was to explore apolipoprotein-defined lipoproteins for abnormalities when comparing non-rheumatological controls to rheumatoid arthritis (RA) patients. METHODS: Apolipoprotein and lipoprotein profiles were measured on 94 RA patients and 79 controls by immunoturbidimetric procedures, electroimmunoassays, and immunoprecipitation. Differences between means were tested with a two-sided Student t test with Satterthwaite adjustment. p-values were adjusted for multiple comparisons using the Bonferroni procedure. RESULTS: RA patients had significantly higher levels of total cholesterol (TC), triglycerides (TG), and very low density lipoprotein cholesterol (VLDL-C) than controls, but no significant differences in the levels of high density lipoprotein cholesterol (HDL-C) and LDL-C. RA patients had significantly lower levels of apolipoprotein (apo)A-I and lipoprotein (Lp)A-I:A-II, but no difference in levels of LpA-I than normal controls. There was a significant difference in the levels of LpB:C but not in LpB:C:E between RA patients and controls. The main abnormality among apoB lipoproteins was the significantly increased concentration of the LpA-II:B:C:D:E subclass in RA patients in comparison with controls. The high levels of LpA-II:B:C:D:E are also reflected in significantly increased levels of apoC-III, and apoC-III bound to apoB lipoproteins. CONCLUSION: The LpA-II:B:C:D:E subclass has potential as a new marker for cardiovascular disease (CVD) in RA patients.