IL6 and psoriatic arthritis: However, in some cases, tocilizumab appeared ineffective for psoriatic arthritis and even induced or exacerbated psoriasis;155 this might be explained by the absence of IL-6 leading to excessive production of additional proinflammatory cytokines by keratinocytes.156 These findings may provide a new insight into why the blockage of IL-6 was ineffective in the treatment of psoriasis and why some patients with RA treated with IL-6 inhibitors had newly onset psoriasis.