[Current therapeutic options in Sjögren's syndrome]

Cellular Targeting of Oligonucleotides by Conjugation with Small Molecules

Drug candidates derived from oligonucleotides (ON) are receiving increased attention that is supported by the clinical approval of several ON drugs. Such therapeutic ON are designed to alter the expression levels of specific disease-related proteins, e.g., by displaying antigene, antisense, and RNA interference mechanisms. However, the high polarity of the polyanionic ON and their relatively rapid nuclease-mediated cleavage represent two major pharmacokinetic hurdles for their application in vivo. This has led to a range of non-natural modifications of ON structures that are routinely applied in the design of therapeutic ON. The polyanionic architecture of ON often hampers their penetration of target cells or tissues, and ON usually show no inherent specificity for certain cell types. These limitations can be overcome by conjugation of ON with molecular entities mediating cellular 'targeting', i.e., enhanced accumulation at and/or penetration of a specific cell type. In this context, the use of small molecules as targeting units appears particularly attractive and promising. This review provides an overview of advances in the emerging field of cellular targeting of ON via their conjugation with small-molecule targeting structures.

Advances in Mast Cell Activation by IL-1 and IL-33 in Sjögren's Syndrome: Promising Inhibitory Effect of IL-37

Sjögren's syndrome (SS) is a chronic autoimmune inflammatory disease that affects primarily older women and is characterized by irreversible damage of the exocrine glands, including tear (xerophthalmia) and salivary glands (xerostomia). Secretory glands lose their functionality due to the infiltration of immune cells, which produce cytokines and cause inflammation. Primary SS is characterized by dry syndrome with or without systemic commitment in the absence of other pathologies. Secondary SS is accompanied by other autoimmune diseases with high activation of B lymphocytes and the production of autoantibodies, including the rheumatoid factor. Other cells, such as CD4+ T cells and mast cells (MCs), participate in SS inflammation. MCs are ubiquitous, but are primarily located close to blood vessels and nerves and can be activated early in autoimmune diseases to express a wide variety of cytokines and chemokines. In the SS acute phase, MCs react by generating chemical mediators of inflammation, tumor necrosis factor (TNF), and other pro-inflammatory cytokines such as interleukin (IL)-1 and IL-33. IL-33 is the specific ligand for ST2 capable of inducing some adaptive immunity TH2 cytokines but also has pro-inflammatory properties. IL-33 causes impressive pathological changes and inflammatory cell infiltration. IL-1 family members can have paracrine and autocrine effects by exacerbating autoimmune inflammation. IL-37 is an IL-1 family cytokine that binds IL-18Rα receptor and/or Toll-like Receptor (TLR)4, exerting an anti-inflammatory action. IL-37 is a natural inhibitor of innate and acquired immunity, and the level is abnormal in patients with autoimmune disorders. After TLR ligand activation, IL-37 mRNA is generated in the cytoplasm, with the production of pro-IL-37 and later mature IL-37 caspase-1 mediated; both precursor and mature IL-37 are biologically active. Here, we discuss, for the first time, the current knowledge of IL-37 in autoimmune disease SS and propose a new therapeutic role.

[Sensory neuronopathy of Sjögren's syndrome. A diagnostic challenge]

Sjögren's syndrome is an important differential diagnosis in patients with sensory neuronopathy because immunosuppressive therapy may prevent progressive degeneration of sensory fibres, ganglions and axons. Due to the challenges in the diagnostic process the diagnostic criteria have repeatedly changed over the past few years. In patients with negative antibodies (SSA, SSB antibodies) biopsy of the salivary glands of the lip and the parotid gland can be useful to diagnose Sjögren's syndrome. We report on four patients in whom biopsy of the salivary gland was helpful in establishing the diagnosis of Sjögren's syndrome and consequently immunosuppressive therapy was initiated. One of these patients suffered from hypersalivation. This was probably due to denervation hypersensitivity. To our knowledge this has not been reported yet.

[Sjögren syndrome]

Sjögren's syndrome (SS) is a chronic inflammatory disorder of hitherto unknown origin. The characteristic hallmark of SS is focal lymphocytic infiltration and slow destruction of exocrine glands, such as lacrimal and salivary glands. Sicca symptoms and/or recurrent parotid gland swelling are often accompanied by fatigue. Clinically relevant extraglandular manifestations occur in more than 20% of patients with primary SS. The development of malignant B cell lymphoma is the most important complication, which affects about 5% of primary SS patients who are at higher risk to develop malignant B cell lymphoma, both when compared with the general population as well as with patients with SS secondary to other systemic autoimmune disorders. Treatment of sicca symptoms is primarily symptomatic, whereas glucocorticoids, NSAIDs and/or immunosuppressive drugs may be indicated for the treatment of extraglandular manifestations. New therapeutic strategies, such as B cell targeted therapies, are in clinical testing especially for patients with severe organ manifestations.