Effects of the anti-interleukin-6 receptor antibody, tocilizumab, on serum lipid levels in patients with rheumatoid arthritis

We investigated the effects of anti-IL-6 receptor antibody, tocilizumab (TCZ), on lipid metabolism. Nineteen patients with rheumatoid arthritis (RA), entered in clinical case–control study of SAMURAI trial at Sasebo Chuo Hospital, were examined. Nine patients received TCZ monotherapy at 8 mg/kg intravenously every 4 weeks (TCZ group) and 10 patients received conventional DMARDs (control group). Serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), apolipoprotein (Apo) A-1, Apo A-2 and Apo B as well as disease activity score (DAS), C-reactive protein and serum amyloid A protein were examined at baseline and after 3 months of the treatment. IL-6 inversely was correlated with LDL, Apo A-1 and Apo A-2, and also tended to correlate with Apo B. In TCZ group, serum levels of TC, HDL, LDL, Apo A-1 and Apo A-2 were significantly increased after 3 months treatment with TCZ. There was no significant change in Apo B, the atherogenic index, and TC/HDL by the TCZ treatment. Changes in the DAS28-ESR negatively correlated with those in TC. In one patient, whose serum level of TCZ was not detected after 3 months of the treatment, the absence of the increment in serum levels of Apo A-1 and A-2 in the patient was remarkable. All of the markers did not change during 3 months in control group. These data may raise an important issue to evaluate the impact of these alternations in lipid metabolism for longer periods in RA patients treated with TCZ.