Insights into the cellular basis of skin inflammation in systemic autoimmune rheumatic diseases from single-cell technologies.

Cutaneous inflammation is a common feature of several systemic autoimmune rheumatic diseases (SARDs) including systemic lupus erythematosus (SLE), undifferentiated connective tissue disease (UCTD), mixed connective tissue disease (MCTD) and dermatomyositis (DM) but is less common in other SARDs such as primary Sjögren's syndrome (pSS). It is important to understand whether the pathophysiological processes underlying skin inflammation are different or shared between SARDs to develop targeted therapies. This review will discuss commonalities and differences between inflammatory skin disease in SARDs focusing on histopathology and describe newer insights obtained from single-cell technologies.

Proteomic analysis identifies subgroups of patients with active systemic lupus erythematosus.

OBJECTIVE: Systemic lupus erythematosus (SLE) is a clinically and biologically heterogenous autoimmune disease. We aimed to investigate the plasma proteome of patients with active SLE to identify novel subgroups, or endotypes, of patients. METHOD: Plasma was collected from patients with active SLE who were enrolled in the British Isles Lupus Assessment Group Biologics Registry (BILAG-BR). The plasma proteome was analysed using a data-independent acquisition method, Sequential Window Acquisition of All theoretical mass spectra mass spectrometry (SWATH-MS). Unsupervised, data-driven clustering algorithms were used to delineate groups of patients with a shared proteomic profile. RESULTS: In 223 patients, six clusters were identified based on quantification of 581 proteins. Between the clusters, there were significant differences in age (p = 0.012) and ethnicity (p = 0.003). There was increased musculoskeletal disease activity in cluster 1 (C1), 19/27 (70.4%) (p = 0.002) and renal activity in cluster 6 (C6) 15/24 (62.5%) (p = 0.051). Anti-SSa/Ro was the only autoantibody that significantly differed between clusters (p = 0.017). C1 was associated with p21-activated kinases (PAK) and Phospholipase C (PLC) signalling. Within C1 there were two sub-clusters (C1A and C1B) defined by 49 proteins related to cytoskeletal protein binding. C2 and C6 demonstrated opposite Rho family GTPase and Rho GDI signalling. Three proteins (MZB1, SND1 and AGL) identified in C6 increased the classification of active renal disease although this did not reach statistical significance (p = 0.0617). CONCLUSIONS: Unsupervised proteomic analysis identifies clusters of patients with active SLE, that are associated with clinical and serological features, which may facilitate biomarker discovery. The observed proteomic heterogeneity further supports the need for a personalised approach to treatment in SLE.

Spontaneous hepatic artery dissection-a rare presentation of fibromuscular dysplasia.

Fibromuscular dysplasia (FMD) is a rare condition that causes structural compromise of the blood vessel presenting either as an incidental radiological finding, dissection or stenosis usually of the renal or craniocervical arteries. Seldom, patients present with spontaneous dissection in visceral arteries and there are few reports of hepatic involvement. This report outlines the case of a 43-year-old female who presented with severe right upper quadrant pain with a subsequent diagnosis of FMD manifesting as spontaneous hepatic artery dissection. The patient was treated with conservative antiplatelet therapy and regular radiographic follow-up, decided by the treating team as no clear guidelines exist for management of this particular presentation of FMD. Surgical management is not currently recommended to this patient due to the risk of further dissection, but may be considered if there is severe haemodynamic compromise or refractory pain.