Might tocilizumab be useful in patients with giant-cell arteritis and normal ESR?

We read with great interest the original article “Rapid induction of remission in large vessel vasculitis by IL-6 blockade” by Dr. Seitz et al. [1]. One of us (F.J.F-F) is very interested in the treatment of giant-cell arteritis because his mother was diagnosed with giant-cell arteritis 5 months previously. She had polymyalgia rheumatic for several months, and headache was the main manifestation of her arteritis. She is 82 years-old and has hypertension and diabetes mellitus. She did not have anaemia or constitutional symptoms. C-reactive protein and erythrocyte sedimentation rate (ESR) were low when she was diagnosed with giant cell arteritis (5.4 mg/L and 34 mm/h, respectively). The values of these parameters were normal when she was diagnosed with polymyalgia rheumatica. One week after treatment with 60 mg/day of prednisone, which was the used dose for the initial management of her arteritis, her serum levels of IL-6 and C-reactive protein were 2.8 pg/ml and 0.31 mg/L, respectively. During a relapse, 3 months after the diagnosis of giant-cell arteritis, IL-6, C-reactive protein and ESR were elevated to 5.8 pg/ml, 8.1 mg/L and 26 mm/ h, respectively. Her treatment with prednisone is accompanied by a notable worsening of her diabetes requiring treatment with insulin. Furthermore, central nervous system manifestations with insomnia and irritability were remarkable. In other recent case reports, tocilizumab has been used successfully in patients with giant-cell arteritis and elevated acute phase reactants [2–3]. Theoretically, one might think that tocilizumab would not be useful in patients with giantcell arteritis and a weak inflammatory response. The article by Dr. Seitz and colleagues is interesting in several respects. On the one hand, in two of their patients monotherapy with tocilizumab only was used to induce remission. On the other hand, one of their patients had normal ESR and C-reactive protein. We would like to know whether Seitz and colleagues measured the serum levels of IL-6 before and after treatment with tocilizumab. Particularly, it would be interesting to know whether their patient with normal ESR had normal values of IL-6 before treatment with tocilizumab. Perhaps, tocilizumab may be the steroidsparing agent that we are expecting if the results of Seitz and colleagues are confirmed by larger series of patients.