Pyoderma gangrenosum-a novel approach?

Abstract

Pyoderma gangrenosum (PG) represents a rare skin disorder, with several clinical variants and still not fully understood ethiopathogenesis. Often associated with inflammatory or neoplastic disease, PG is nowadays considered an inflammatory neutrophilic disease with common underlying morbidity. Modern treatment options are oriented towards key mechanisms underlying the pathogenesis of the disease, namely inflammatory mediators, and seem to be the most effective treatment currently available. Although promising, the results are not invariable and these treatments are sometimes surrounded by controversy, as recent studies have reported cases that are refractory to therapy with biological agents. It is possible that refractoriness to the use of biological agents as monotherapy stems from the fact that a single agent is not able to affect the entire inflammatory cascade, or to simultaneously influence all of its levels. Based on the pathogenesis of inflammation, we can suggest that an ideal targeted therapy should be able to induce the following changes: 1) reduction of the secretion of interleukin (IL)-1a/b from the inflammasome with subsequent blocking of its biological effect (by therapy with IL-1 receptor antagonists); 2) blocking of the activation of the secreted procytokines in their active form (by therapy with caspase-1 inhibitors; 3) blocking of the effect of the already released active cytokines (by therapy with tumour necrosis factor alpha, TNF-α, inhibitors); 4) blocking of the effector action of the cytokines on the target intracellular molecules (by therapy with kinase inhibitors). The specific therapy should aim to attack more than one link in the inflammatory cascade, in order to achieve maximum therapeutic effectiveness. Most surely, this could be achieved with combined therapy with different groups of biological agents (for example a combined therapy with IL-1 receptor antagonist and a TNF-α inhibitor). Currently, no data in the literature exist to support this statement, and there are no safety data relating to such approaches. We focus this review on the novel etiopathogenetic concepts of PG and the future therapeutic approaches based on blocking different levels of the inflammatory cascade, which seems to be the most promising weapon in the target-oriented treatment options.

Keywords: Biological agents; Etiopathogenesis; Neutrophilic disorders; Pyoderma gangrenosum; Treatment.