Drug survival rates should be integrated into therapeutic decisions in order to provide patients with an optimal long-term strategy.

SummaryBackgroundPalmoplantar pustulosis (PPP) is a chronic inflammatory skin disease‐related to psoriasis. Its treatment is challenging, and little is known about the sustainability of different medications. The aim of this study was to analyze drug survival rates and drug discontinuation in the treatment of PPP under real‐world conditions.Patients and MethodsPatients with PPP treated in the dermatology departments of five German university medical centers between 01/2005 and 08/2017 were included in our retrospective study. Drug survival of systemic therapies was assessed with Kaplan‐Meier analysis and multivariate regression.ResultsOverall, 347 patients with 935 treatment courses were identified. Within the group of non‐biologic systemic agents, apremilast showed the highest median drug survival (15 months), followed by cyclosporine (12 months), the combination of acitretin and topical PUVA (9 months), MTX (8 months), acitretin monotherapy (6 months), alitretinoin (5 months), and fumaric acid esters (3 months). Among biologicals, the highest maintenance rate was detected for certolizumab pegol (restricted mean: 47.4 months), followed by infliximab (median: 26 months), golimumab (22 months), ustekinumab (21 months), adalimumab (18 months), secukinumab (9 months), and etanercept (8 months).ConclusionsBiologicals and apremilast may serve as second‐line options for treatment of PPP and should be further evaluated.

Binding of the serum protein complement component C1q to the surface of dying cells facilitates their clearance by phagocytes in a process termed efferocytosis. Here, we investigate during which phase of apoptotic cell death progression C1q binding takes place. Purified C1q was found to bind to all dying cells and, albeit weaker, also to viable cells. The presence of serum abrogated completely the binding to viable cells. In addition, C1q binding to dying cells was limited to a specific subpopulation of late apoptotic/secondary necrotic cells. Co-culturing serum-treated apoptotic cells with human monocytes revealed a much higher phagocytosis of C1q-positive than of C1q-negative late apoptotic/secondary necrotic cells. But this phagocytosis-promoting activity could not be observed with purified C1q. Serum-treated C1q-positive late apoptotic/secondary necrotic cells exhibited a similar volume, a similar degraded protein composition, but a much lower DNA content in comparison with the remaining late apoptotic/secondary necrotic cells. This was mediated by a serum-bound nuclease activity that could be abrogated by G-actin, which is a specific inhibitor of serum DNase I. These results show that serum factors are involved in the prevention of C1q binding to viable cells and in the processing of late apoptotic/secondary necrotic cells promoting cell death progression toward apoptotic bodies. This process leads to the exposure of C1q-binding structures and facilitates efferocytosis.