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Introduction Kawasaki disease (KD), first described as an acute, febrile, mucocutaneous lymph node syndrome in 1967 (1), is the most common systemic vasculitis of children and infants. KD is recognized [...], Environmental triggers, including those from pathogens, are thought to play an important role in triggering autoimmune diseases, such as vasculitis, in genetically susceptible individuals. The mechanism by which activation of the innate immune system contributes to vessel-specific autoimmunity in vasculitis is not known. Systemic administration of Candida albicans water-soluble extract (CAWS) induces vasculitis in the aortic root and coronary arteries of mice that mimics human Kawasaki disease. We found that Dectin-2 signaling in macrophages resident in the aortic root of the heart induced early CCL2 production and the initial recruitment of [CCR2.sup.+] inflammatory monocytes (iMos) into the aortic root and coronary arteries. iMos differentiated into monocyte-derived dendritic cells (Mo-DCs) in the vessel wall and were induced to release IL-1[beta] in a Dectin-2/Syk/NLRP3 inflammasome-dependent pathway. IL-1[beta] then activated cardiac endothelial cells to express CXCL1 and CCL2 and adhesion molecules that induced neutrophil and further iMo recruitment and accumulation in the aortic root and coronary arteries. Our findings demonstrate that Dectin-2-mediated induction of CCL2 production by macrophages resident in the aortic root and coronary arteries initiates vascular inflammation in a model of Kawasaki disease, suggesting an important role for the innate immune system in initiating vasculitis.

The article presents a case study reported in the Journal of Cutaneous Immunology and Allergy, on skin manifestations in granulomatosis with polyangiitis (GPA), a type of systemic vasculitis. The case study focuses on a 61-year-old woman with GPA who exhibited erythema nodosum (EN)-like eruptions as a sole vasculitis-associated cutaneous manifestation, highlighting the importance of recognizing EN-like eruption as a possible symptom of GPA affecting medium-sized vessels.

As lithium carbonate is frequently used for treating mania symptoms in bipolar disorder, we should recognize that it can cause serious drug eruptions including SJS. Dear Editor, A 56-year-old Japanese woman who had been suffering from bipolar disorder for 12 years developed erythema on the legs. To our knowledge, this is the first case report describing lithium carbonate-induced SJS. [Extracted from the article]

Eosinophilic granulomatosis with polyangiitis (EGPA) belongs to the family of antineutrophil cytoplasmic antibody (ANCA)‐associated vasculitis syndromes. Although increasing evidence indicates the correlation of clinical and histological features with the presence or absence of ANCAs in EGPA, the variations in cutaneous features according to their ANCA status have not been fully described. Here, we retrospectively reviewed the clinical and histological findings of 9 cases of EGPA, who presented with cutaneous lesions. Our data indicate that ANCA‐positive patients often present with blisters, systemic inflammatory symptoms, and are prone to receive a higher dose of oral prednisolone and additional immunosuppressive therapies. [ABSTRACT FROM AUTHOR]

Dear Editor, Waldenström's macroglobulinemia (WM) is a low-grade chronic B-cell lymphoproliferative disorder characterized by bone marrow infiltration of small lymphocytes, lymphoplasmacytoid cells, and plasma cells that secrete monoclonal immunoglobulin M (IgM) protein.1 There is no established treatment approach with curative potential to date; therefore, patients with WM ultimately relapse. He had been diagnosed with WM 12 years prior on the basis of elevated serum IgM with monoclonal IgM- protein and lymphoplasmacytic cell proliferation in the bone marrow. Cutaneous manifestations can be the initial presentation of WM.5 Our observations indicate that skin manifestation by tumor cell infiltration can also precede systemic relapse of the disease. [Extracted from the article]

Objectives: Randomised-controlled trials have recently proven the efficacy of the interleukin (IL)-6 receptor antagonist tocilizumab (TCZ) in giant cell arteritis (GCA). However, the mechanism of action of IL-6 blockade in this disease is unknown. Moreover, the role of regulatory T (Treg) cells in the pathogenesis of GCA remains underexplored. Given the plasticity of Tregs and the importance of IL-6 in their biology, we hypothesised that TCZ might modulate the Treg response in GCA. We therefore characterised the Treg compartment of patients with GCA treated with TCZ.Methods: We classified 41 patients with GCA into three groups: active disease (aGCA, n=11), disease remission on corticosteroids (rGCA-CS, n=19) and disease remission on TCZ (rGCA-TCZ, n=11). Healthy controls (HCs) were included for comparison. We determined the frequency, phenotype and function of peripheral blood Tregs.Results: Patients with aGCA demonstrated a hypoproliferating Treg compartment enriched in IL-17-secreting Tregs (IL-17+Tregs). Tregs in patients with aGCA disproportionally expressed a hypofunctional isoform of Foxp3 that lacks exon 2 (Foxp3Δ2). Foxp3Δ2-expressing Tregs coexpressed CD161, a marker commonly associated with the Th17 linage, significantly more often than full-length Foxp3-expressing Tregs. Compared with those of HCs, GCA-derived Tregs demonstrated impaired suppressor capacity. Treatment with TCZ, in contrast to CS therapy, corrected the Treg abnormalities observed in aGCA. In addition, TCZ treatment increased the numbers of activated Tregs (CD45RA-Foxp3high) and the Treg expression of markers of trafficking (CCR4) and terminal differentiation (CTLA-4).Conclusions: TCZ may exert its therapeutic effects in GCA by increasing the proliferation and activation of Tregs, and by reverting the pathogenic Treg phenotype seen during active disease. [ABSTRACT FROM AUTHOR]