Evidence of B Cell Clonality and Investigation Into Properties of the IgM in Patients With Schnitzler Syndrome.

The Schnitzler Syndrome (SchS) is an acquired, autoinflammatory condition successfully treated with IL-1 inhibition. The two main defining features of this late-onset condition are neutrophilic urticarial dermatoses (NUD) and the presence of an IgM monoclonal component. While the former aspect has been extensively studied in this disease setting, the enigmatic paraproteinaemia and its potential consequential effects within SchS, has not previously been thoroughly addressed. Previous studies analyzing clonal B cell repertoires have largely focused on autoimmune disorders such as Systemic Lupus Erythematous (SLE) and hematological malignancies such as Chronic Lymphocytic Leukaemia (CLL), where B-cell clonality is central to disease pathology. The present study uses next-generation sequencing to provide detailed insight into aspects of B cell VDJ recombination and properties of the resulting immunoglobulin chains. An overview of IgH regional dynamics in 10 SchS patients, with a particular focus on CDR3 sequences and VDJ gene usage is reported, highlighting the presence of specific B cell expansions. Protein microarray detected a substantial proportion of autoreactive IgM to nuclear target proteins, though a single universal target was not identified. Together, these genetic and functional findings impart new understanding into this rare disorder.

Schnitzler's syndrome - a novel hypothesis of a shared pathophysiologic mechanism with Waldenström's disease.

Schnitzler's syndrome is an auto-inflammatory disorder which is characterized by two mandatory features: an urticarial rash and a monoclonal gammopathy. Although the pathophysiology of this syndrome is not yet fully understood, a role for interleukin-1 seems apparent. While this presumed link between interleukin-1 and the monoclonal gammopathy is not yet elucidated, a mutual factor in pathophysiology however seems likely. Here we present a novel hypothesis of a shared pathophysiologic mechanism between Schitzler's syndrome and monoclonal gammopathy.

Schnitzler Syndrome: a Review.

PURPOSE OF REVIEW: We focus on recent advances in diagnosis and therapeutic strategies, as well as on pathogenesis of Schnitzler syndrome. RECENT FINDINGS: New diagnostic criteria were established, and their external validity was assessed in a retrospective cohort study. The cytokine interleukin-1 (IL-1) plays a crucial role in the pathogenesis of the Schnitzler syndrome, and this explains the spectacular efficiency of IL-1 blocking therapies. The Schnitzler syndrome is now considered as a late-onset acquired autoinflammatory syndrome in which the cytokine IL-1 plays a crucial role. IL-1 blocking therapies are efficient on the inflammation-linked symptoms but not on the monoclonal component. Therefore, they probably don't reduce the risk of the development of lymphoproliferative disorders that remains the main prognostic issue. The link between autoinflammation and the monoclonal component needs to be further elucidated.

Interleukin-1 Blockade: An Update on Emerging Indications.

Interleukin (IL)-1 is a pro-inflammatory cytokine that induces local and systemic inflammation aimed to eliminate microorganisms and tissue damage. However, an increasing number of clinical conditions have been identified in which IL-1 production is considered inappropriate and IL-1 is part of the disease etiology. In autoinflammatory diseases, gout, Schnitzler's syndrome, and adult-onset Still's disease, high levels of inappropriate IL-1 production have been shown to be a key process in the etiology of the disease. In these conditions, blocking IL-1 has proven very effective in clinical studies. In other diseases, IL-1 has shown to be present in disease process but is not the central driving force of inflammation. In these conditions, including type 1 and 2 diabetes mellitus, acute coronary syndrome, amyotrophic lateral sclerosis, and several neoplastic diseases, the benefits of IL-1 blockade are minimal or absent.

Clinical characterization and long-term follow-up of Schnitzler syndrome.

BACKGROUND: Schnitzler syndrome (SchS) is an acquired autoinflammatory disease characterized by chronic urticarial rash in association with monoclonal gammopathy. Patients may progress to lymphoproliferative disorders, but the associated factors and exact risk of progression are still not well defined. AIM: To characterize the clinical findings, laboratory abnormalities and histopathology of patients with SchS and their respective outcomes. METHODS: We retrospectively reviewed the clinical files and the histological specimens of patients with SchS diagnosed from 1988 to 2015. RESULTS: Nine patients (two women, seven men) were diagnosed with SchS. Mean age at diagnosis was 61.1 years (range 29-80), with a mean time to diagnosis of 3.7 years and a mean follow-up period of 10.1 years (range 3-25). Four patients displayed an association of fever and arthralgia, and all nine patients consistently showed laboratory markers of inflammation. Serum values of the monoclonal component, IgMκ in eight patients and IgGλ in one patient, progressively increased over time. During follow-up, carried out in association with the haematology department five patients progressed to lymphoproliferative disease, namely, lymphoplasmacytic lymphoma/Waldenström's macroglobulinaemia (n = 4) and diffuse large B-cell lymphoma (n = 1). CONCLUSIONS: SchS is a rare chronic inflammatory disease with a substantial impact on quality of life. Our study highlights the importance of lifelong follow-up for individuals with SchS, owing to the risk of progression to a lymphoproliferative disorder.

Mast-cell interleukin-1ß, neutrophil interleukin-17 and epidermal antimicrobial proteins in the neutrophilic urticarial dermatosis in Schnitzler's syndrome.

BACKGROUND: Schnitzler's syndrome (SchS) is an autoinflammatory disease characterized by a chronic urticarial rash, a monoclonal component and signs of systemic inflammation. Interleukin (IL)-1ß is pivotal in the pathophysiology. OBJECTIVES: Here we investigated the cellular source of proinflammatory mediators in the skin of patients with SchS. METHODS: Skin biopsies of lesional and nonlesional skin from eight patients with SchS and healthy controls, and patients with cryopyrin-associated periodic syndrome (CAPS), delayed-pressure urticaria (DPU) and cold-contact urticaria (CCU) were studied. We studied in vivoIL-1ß, IL-17 and antimicrobial protein (AMP) expression in resident skin cells and infiltrating cells. In addition we investigated the in vitro effect of IL-1ß, IL-17 and polyinosinic-polycytidylic acid (poly:IC) stimulation on cultured epidermal keratinocytes. RESULTS: Remarkably, we found IL-1ß-positive dermal mast cells in both lesional and nonlesional skin of patients with SchS, but not in healthy control skin and CCU, and fewer in CAPS. IL-17-positive neutrophils were observed only in lesional SchS and DPU skin. In lesional SchS epidermis, mRNA and protein expression levels of AMPs were strongly increased compared with nonlesional skin and that of healthy controls. When exposed to IL-1ß, poly:IC or IL-17, patient and control primary human keratinocytes produced AMPs in similar amounts. CONCLUSIONS: Dermal mast cells of patients with SchS produce IL-1ß. This presumably leads to activation of keratinocytes and neutrophil influx, and further amplification of inflammation by IL-17 (from neutrophils and mast cells) and epidermal AMP production leading to chronic histamine-independent neutrophilic urticarial dermatosis.

Effect of in vitro and in vivo anakinra on cytokines production in Schnitzler syndrome.

IL-1 receptor antagonist anakinra is usually highly efficient in Schnitzler syndrome (SS), a rare inflammatory condition associating urticaria, fever, and IgM monoclonal gammopathy. In this study, we aimed to assess lipopolysaccharide (LPS)-induced production of inflammatory cytokines by peripheral blood mononuclear cells (PBMCs) before and after 1 month of anakinra in patients with SS. LPS-induced production of IL-1ß, IL-6 and TNFα was assessed by enzyme-linked immunosorbent assay with and without anakinra in vitro, and before and after 1 month (in vivo condition) of treatment in 2 patients with SS. Spontaneous production of IL-1ß, IL-6 and TNF-α by PBMCs was similar in the patients and the healthy controls and was almost undetectable. Stimulation with LPS caused a higher release of cytokines from the patients than from the healthy controls. Before in vivo anakinra start, in vitro adjunction of anakinra reduced the high LPS-induced production of IL-1ß and TNFα in both patients and of IL-6 in one patient. After 1 month of treatment with anakinra, while the patients had dramatically improved, there was also a marked reduction in LPS-induced cytokines production, which was almost normalized in one patient. This study shows an abnormal LPS-induced inflammatory cytokines production in SS, which can be decreased or even normalized by in vitro and in vivo anakinra.

Efficacy and safety of the interleukin-1 antagonist rilonacept in Schnitzler syndrome: an open-label study.

BACKGROUND: Schnitzler syndrome (SchS) is a rare disease with suspected autoinflammatory background that shares several clinical symptoms, including urticarial rash, fever episodes, arthralgia, and bone and muscle pain with cryopyrin-associated periodic syndromes (CAPS). Cryopyrin-associated periodic syndromes respond to treatment with interleukin-1 antagonists, and single case reports of Schnitzler syndrome have shown improvement following treatment with the interleukin-1 blocker anakinra. This study evaluated the effects of the interleukin-1 antagonist rilonacept on the clinical signs and symptoms of SchS. METHODS: Eight patients with SchS were included in this prospective, single-center, open-label study. After a 3-week baseline, patients received a subcutaneous loading dose of rilonacept 320 mg followed by weekly subcutaneous doses of 160 mg for up to 1 year. Efficacy was determined by patient-based daily health assessment forms, physician's global assessment (PGA), and measurement of inflammatory markers including C-reactive protein (CRP), serum amyloid A (SAA), and S100 calcium-binding protein A12 (S100A12). RESULTS: Treatment with rilonacept resulted in a rapid clinical response as demonstrated by significant reductions in daily health assessment scores and PGA scores compared with baseline levels (P < 0.05). These effects, which were accompanied by reductions in CRP and SAA, continued over the treatment duration. Rilonacept treatment was well tolerated. There were no treatment-related severe adverse events and no clinically significant changes in laboratory safety parameters. CONCLUSION: Rilonacept was effective and well tolerated in patients with SchS and may represent a promising potential therapeutic option.