Search

Summary: Background: Schnitzler syndrome (SchS) is a rare autoinflammatory disease characterized by urticarial exanthema, bone and joint alterations, fever and monoclonal gammopathy, which manifest mostly in the second half of life. It involves overactivation of the interleukin (IL)‐1 system, but the exact pathophysiological pathways remain largely unknown. Objectives: To identify and characterize the pathogenetic players in SchS. Methods: Blood parameters were quantified in patients with SchS compared with healthy controls and patients with psoriasis and hidradenitis suppurativa using enzyme‐linked immunosorbent assay (ELISA). CCL2 expression in cultured primary cells was analysed by quantitative reverse‐transcriptase polymerase chain reaction and ELISA. Results: CCL2, a chemoattractant for monocytic and further mononuclear immune cells, was found to be significantly elevated in patients with SchS. CCL2 levels showed a positive association with global disease activity, especially with bone pain, but not disease duration, gammopathy, neutrophilia or skin disease. In vitro stimulation assays demonstrated a strong CCL2 production capacity of mononuclear immune cells and fibroblasts, but not epithelial or endothelial cells. Among a range of inflammatory mediators, only IL‐1β (immune cells, fibroblasts) and tumour necrosis factor (TNF)‐α (fibroblasts) were important CCL2 inducers. TNF‐α, but not IL‐17, strengthened the CCL2‐inducing effect of IL‐1β in fibroblasts. Accordingly, CCL2 levels positively correlated with both TNF‐α and IL‐1β serum levels in patients with SchS. Therapeutic IL‐1β blockade decreased CCL2 blood levels in these patients as early as 1 week after the initiation of treatment. Conclusions: CCL2 may be an important component of the pathogenetic cascade leading to bone alterations, and a suitable marker of disease activity in patients with SchS. What's already known about this topic?Schnitzler syndrome (SchS) is a very rare acquired autoinflammatory disease, clinically characterized by urticarial exanthema, arthralgia and osteosclerosis, and episodes of fever.The pathogenesis involves overactivation of the interleukin‐1 system.The exact pathogenetic pathways are mostly unknown, and biomarkers are not available to assess the inflammatory activity in SchS. What does this study add? The chemokine CCL2 is a marker of SchS; its blood levels are significantly upregulated and linked to global disease activity and early therapy response in patients with SchS.While no clear relationship with patients' urticarial exanthema was detected, CCL2 may be involved in bone alterations in these patients.The cellular sources of CCL2 include mononuclear immune cells and fibroblasts.Interleukin‐1β and tumour necrosis factor‐α, blood levels of which correlate with CCL2 levels in patients with SchS, are important CCL2 inducers. What is the translational message? Quantifying CCL2 blood levels may allow the objective estimation of inflammatory disease activity and may help with the therapy decision in patients with SchS.CCL2 may be a key element of the pathogenetic cascades in SchS, especially those important for osteosclerosis. Linked Comment:Kambe and Nguyen. Br J Dermatol 2019; 180:706–707. Respond to this article Plain language summary available online [ABSTRACT FROM AUTHOR]

Summary: Background: Chronic spontaneous urticaria (CSU) is an inflammatory skin disorder characterized by recurrent weals, angio‐oedema or both. Recent studies have shown that the number of endothelial cells is increased in the skin of patients with CSU, but the underlying mechanisms and clinical implications of this are unclear. Aim: To evaluate whether mast cell (MC) or endothelial cell (EC) numbers correlate with CSU and whether they are relevant for disease duration, disease activity or the presence of clinical features. Methods: We determined the numbers of CD31+ ECs and MCs in nonlesional skin of 30 patients with CSU using quantitative histomorphometry, and assessed their correlation with each other and with clinical features such as disease duration, disease activity and occurrence of angio‐oedema. Results: The numbers of MCs and ECs were high in the nonlesional skin of patients with CSU, but did not correlate with each other. Neither MC number nor EC number correlated with disease duration or disease activity. Interestingly, patients with high numbers of cutaneous CD31+ ECs had higher rates of recurrent angio‐oedema and vice versa. Conclusions: Based on these findings, we speculate that vascular remodelling and MC hyperplasia in patients with CSU occurs independently and via different mechanisms. Targeting of the mechanisms that drive neoangiogenesis in CSU may result in novel therapeutic strategies for the management of patients with angio‐oedema. [ABSTRACT FROM AUTHOR]

Objectives: When tested in broth, avibactam reverses ceftazidime resistance in many Pseudomonas aeruginosa that express ESBLs. We examined whether similar reversal is observed against intracellular forms of P. aeruginosa .Methods: Strains: reference strains; two engineered strains with basal non-inducible expression of AmpC and their isogenic mutants with stably derepressed AmpC; and clinical isolates with complete, partial or no resistance to reversion with avibactam. Pharmacodynamic model: 24 h concentration-response to ceftazidime [0.01-200 mg/L alone or with avibactam (4 mg/L)] of bacteria in broth or bacteria phagocytosed by THP-1 monocytes, with calculation of ceftazidime relative potency ( C s : concentration yielding a static effect) and maximal relative effect [ E max : cfu decrease at infinitely large antibiotic concentrations (efficacy in the model)] using the Hill equation. Cellular content of avibactam: quantification by LC-MS/MS.Results: For both extracellular and intracellular bacteria, ceftazidime C s was always close to its MIC. For ceftazidime-resistant strains, avibactam addition shifted ceftazidime C s to values close to the MIC of the combination in broth. E max was systematically below the detection limit (-5 log 10 ) for extracellular bacteria, but limited to -1.3 log 10 for intracellular bacteria (except for two isolates) with no effect of avibactam. The cellular concentration of avibactam reflected extracellular concentration and was not influenced by ceftazidime (0-160 mg/L).Conclusions: The potential for avibactam to inhibit β-lactamases does not differ for extracellular and intracellular forms of P. aeruginosa , denoting an unhindered access to its target in both situations. The loss of maximal relative efficacy of ceftazidime against intracellular P. aeruginosa was unrelated to resistance via avibactam-inhibitable β-lactamases. [ABSTRACT FROM AUTHOR]

A letter to the editor on benefit of doxycycline therapy in patients with chronic cold urticaria is presented.

The article discusses the use of skin biomarker profiles to distinguish Schnitzler syndrome from chronic spontaneous urticaria. It mentions immunohistochemistry of skin cytokines presented significantly higher numbers of IL-6-positive cells in SchS. It also mentions the need of evaluation of these biomarkers in patients and along with characterization of the role of mast cells and neutrophils in auto inflammatory diseases.

Linked Article: Krause et al. Br J Dermatol 2019; 180:859–868 [ABSTRACT FROM AUTHOR]

Summary: Schnitzler syndrome is a very rare chronic disease, which usually develops in the second half of life. It appears as skin rashes, muscle/skeletal pain and fever episodes. The trigger and molecular processes in the disease are not understood. However, drugs that inhibit the inflammatory molecule called interleukin‐1ß were found to relieve the disease. The authors of this German study wondered which further molecules are involved in Schnitzler syndrome. For this purpose, a range of molecules with inflammatory properties was quantified in the blood of the patients and, as a comparison, in healthy people and patients with other inflammatory diseases. Patients with Schnitzler syndrome were found to have strongly elevated levels of CCL2, a molecule known to attract inflammatory cells to affected tissues and to have a special role in bone alterations. CCL2 levels were particularly high in severely affected patients, especially those with intense bone pain. In the bone, CCL2 is known to be produced by certain bone‐modifying cells. Laboratory experiments revealed that CCL2 was also highly produced by immune cells and connective tissue cells (fibroblasts). Interleukin‐1ß as well as the inflammatory molecule TNF‐α triggered the production of CCL2 by these cells. When patients were treated with an interleukin‐1ß‐blocking drug, health improvement was paralleled by a drop of CCL2 levels. The authors concluded that in Schnitzler syndrome CCL2 is an important player in the inflammation process in bones and other body sites and may be used in the clinic as an indicator of disease severity. Linked Article: Krause et al. Br J Dermatol 2019; 180:859–868 [ABSTRACT FROM AUTHOR]