Schnitzler syndrome: a case report of successful treatment using the anti-CD20 monoclonal antibody rituximab

Schnitzler syndrome and Schnitzler-like syndromes

Schnitzler syndrome is a rare disease of adult-onset with main features including chronic urticarial rash, recurrent fever, arthralgia or arthritis, monoclonal gammopathy of undetermined significance (MGUS), and marked systemic inflammation. Schnitzler syndrome is often underdiagnosed. Patients with Schnitzler syndrome may present to dermatologists and allergists for urticaria, hematologists for MGUS, or rheumatologists for arthritis. It is important to recognize Schnitzler syndrome for its remarkable response to interleukin (IL)-1 blockade. Besides, many cases of Schnitzler-like syndromes do not meet the diagnostic criteria of classical Schnitzler syndrome but display excellent response to IL-1 inhibitors. The overly produced IL-1 is the result of a somatic mosaic gain of function mutation of NLRP3 (nucleotide-binding oligomerization domain [NOD]-like receptor [NLR] family pyrin domain containing 3) gene in some patients with Schnitzler-like syndromes. Inflammasome activation is evident in patients with classical Schnitzler syndrome although no NLRP3 gene mutation is identified. Collectively, Schnitzler syndrome and Schnitzler-like syndromes represent a spectrum of IL-1 mediated adult-onset autoinflammatory diseases.

Schnitzler's syndrome: lessons from 281 cases

Schnitzler’s syndrome is an autoinflammatory disorder characterized by the association of a monoclonal IgM (or IgG) gammopathy, a chronic urticarial rash, and signs and symptoms of systemic inflammation, including fever, arthralgias and bone pain. It was first described in 1972. This review summarizes the clinical features, efficacy of therapies, and follow-up data of the 281 cases that have been reported to date. Also, the results of skin histology, bone imaging, laboratory investigations, and studies of the pathogenesis will be discussed, including the pivotal role of interleukin-1 beta in this disorder.

Schnitzler's syndrome: a case report

Schnitzler's syndrome is an extremely rare entity that poses a challenge for the clinician not only due to its difficult diagnosis but also due to its management. In this article we report a new case and briefly review the current treatment options.

Increased angiogenesis and enhanced bone formation in patients with IgM monoclonal gammopathy and urticarial skin rash: new insight into the biology of Schnitzler syndrome

Schnitzler syndrome is a rare plasma cell disorder the pathogenesis of which is still not fully understood. We evaluated the circulating levels of four major angiogenic cytokines (VEGF, angiogenin, angiopoietin-1 and angiopoietin-2) and six bone remodeling markers (sRANKL, osteoprotegerin, dickkopf-1, CTX, osteocalcin and bone-specific alkaline phosphatase-bALP) in 13 patients with Schnitzler syndrome. At diagnosis, patients had elevated angiogenic cytokines. The mean VEGF levels were almost 3.5-fold higher in Schnitzler syndrome compared to controls, while 10 of 13 patients had higher VEGF than the upper control value. Successful treatment led to a significant reduction in VEGF. Patients with Schnitzler syndrome had increased bone formation (high bALP, osteocalcin and osteoprotegerin) which was not balanced by an increase in bone resorption (normal CTX and sRANKL). These data support a role for VEGF as a new minor criterion in the diagnosis and follow up of Schnitzler syndrome, while the uncoupling of bone remodeling in favor of bone formation justifies the presence of bone densification.

Schnitzler's syndrome associated with pancreatitis: a disease of IL-1 dysregulation

Schnitzler's syndrome (SS) is a rare inflammatory disease of unknown origin characterized by chronic urticaria and monoclonal gammopathy (usually IgM) associated with at least two of the following components: fever, arthralgia or arthritis, bone pain, hepato- and/or splenomegaly, lymphadenopathy, elevated erythrocyte sedimentation rate, leukocytosis, and/or abnormal findings on bone morphological investigations. To date, about 100 cases have been described with only 4 being reported in the USA. The mean time to diagnosis from the onset of disease is 5.4 years, given the varied symptoms with which patients may present. The pathogenesis of SS remains unknown but likely involves dysregulation of the IL-1 pathway. We describe here a 48-year-old woman with a monoclonal IgM gammopathy and a 3-year history of chronic pruritic urticarial dermatosis, unexplained fevers, chronic polyarthritis, lymphadenopathy, leukocytosis, hepatomegaly, and weight loss. She also had a history of chronic pancreatitis as well as a family history of recurrent pancreatitis. The diagnosis of Schnitzler's syndrome was made, and she was successfully treated with the IL-1 receptor antagonist, anakinra.

Improvement of recurrent urticaria in a patient with Schnitzler syndrome associated with B-cell lymphoma with combination rituximab and radiotherapy

Schnitzler syndrome is a rare condition defined by chronic urticaria, osteosclerotic bone lesions, and monoclonal IgM gammopathy. Schnitzler syndrome can precede the onset of a true lymphoproliferative disorder including Waldenström macroglobulinemia and rarely systemic marginal zone B-cell lymphoma. We describe a case of intractable chronic urticaria accompanied by a retroperitoneal neoplasm. IgM monoclonal gammopathy, lumber pain, intermittent fever, and elevation of C-reactive protein were the clues for the diagnosis of Schnitzler syndrome. An evaluation for malignancy using systemic computed tomography scan and fluorodeoxyglucose positron emission tomography revealed the retroperitoneal tumor, and a subsequent bone-marrow aspirate confirmed the diagnosis of B-cell lymphoma. Combined rituximab and radiotherapy ameliorated the skin symptoms. This case indicates that a detailed search for malignant neoplasms might be required for the long-term management of Schnitzler syndrome, and that B-cell lymphomas may contribute to the pathogenesis of this condition.

[Periodic fever syndrome/autoinflammatory syndrome]

Hereditary periodic fever syndromes (autoinflammatory syndromes) are characterised by relapsing fevers and additional manifestations such as skin rashes, mucosal manifestations, and joint pain. Some of these disorders only present with organ manifestations and serological signs of inflammation without obvious fever (e.g. PAPA and Blau syndrome). There is a strong serological inflammatory response with an elevation of serum amyloid A (risk of secondary amyloidosis). There are monogenic disorders for which the mode of inheritance and gene mutation are known, but probably also polygenic diseases which present with similar symptoms to the classic autoinflammatory syndromes. Gene mutations have been described for the monogenic disorders (FMF, HIDS, CAPS, PAPA and Blau syndrome), which lead to an induction of the production of IL-1ss. Therapeutically, the IL-1-receptor antagonist anakinra is mainly used. In the case of TRAPS and Blau syndrome, TNF antagonists may also be used. PFAPA syndrome, the Schnitzler syndrome, Still's disease of adult and pediatric onset, Behçet's disaese and Crohn's disease also are mentioned as additional possible autoinflammatory syndromes.

Autoinflammatory syndromes with a dermatological perspective

The term autoinflammatory syndromes describes a distinct group of systemic inflammatory diseases apparently different from infectious, autoimmune, allergic and immunodeficient ones. Originally, it was almost synonymous with clinically defined hereditary periodic fever syndromes, including familial Mediterranean fever, hyper immunoglobulin D syndrome with periodic fever and tumor necrosis factor receptor-associated periodic syndrome. Similar but distinct periodic fever syndromes accompanied by urticarial rash, familial cold autoinflammatory syndrome, Muckle-Wells syndrome and chronic infantile neurological cutaneous articular syndrome, have all been reportedly associated with CIAS1 mutations and are collectively called cryopyrin-associated periodic syndromes. Consequently, the concept of autoinflammatory syndromes has been spread to contain other systemic inflammatory diseases: rare hereditary diseases with or without periodic fevers, such as pyogenic sterile arthritis, pyoderma gangrenosum and acne syndrome, Blau syndrome and chronic recurrent multifocal osteomyelitis, and the more common collagen disease-like diseases, such as Behcet's disease, Crohn's disease, sarcoidosis and psoriatic arthritis. These diseases are all caused by or associated with mutations of genes regulating innate immunity and have common clinical features accompanied with activation of neutrophils and/or monocytes/macrophages. In this review, major autoinflammatory syndromes are summarized and the pathophysiology of related skin disorders is discussed in association with dysregulated innate immune signaling.