We investigated associations at baseline and during tocilizumab treatment among haemoglobin , parameters of haemoglobin and iron homeostasis -LSB- ferritin , total iron-binding capacity ( TIBC ) , hepcidin , haptoglobin -RSB- , IL-@ and acute-phase reactants -LSB- C-reactive protein ( CRP ) , erythrocyte sedimentation rate ( ESR ) -RSB- to identify statistical correlates of rise in haemoglobin level .