Anti-SMN autoantibodies in mixed connective tissue disease are associated with a severe systemic sclerosis phenotype.

OBJECTIVES: The survival of motor neuron (SMN) complex has an essential role in the assembly of small nuclear ribonucleoproteins (RNP). Recent reports have described autoantibodies (aAbs) to the SMN complex as novel biomarkers in anti-U1RNP+ myositis patients. The aim of this study was to compare phenotypic features of anti-U1RNP+ mixed connective tissue disease (MCTD) patients with and without anti-SMN aAbs. METHODS: A retrospective MCTD cohort was studied. Addressable laser bead immunoassay was used to detect specific anti-SMN aAbs with <300 mean fluorescence intensity (MFI) as normal reference range, 300-999 MFI as low-titre and ≥1000 MFI as high-titre positivity. Comparison of clinical features between anti-SMN+ and anti-SMN- subgroups used two-tailed Fisher's exact test, and logistic regression analyses. RESULTS: Sixty-six patients were included. Median age at MCTD diagnosis was 40.6 years, and duration of follow-up was 12 years. Based on the highest available titre, 39 (59%) were anti-SMN+: 10 (26%) had low titre and 29 (74%) had high titre. Anti-SMN+ patients had a higher frequency of fingertip pitting scars (anti-SMN+ 23% vs anti-SMN- 4%, p=0.04), lower gastrointestinal (GI) involvement (26% vs 4%, p=0.04), and myocarditis (16% vs 0%, p=0.04). The combined outcome of pitting scars and/or lower GI involvement and/or myositis and/or myocarditis was highest among high-titre anti-SMN+ patients: adjusted OR 7.79 (2.33 to 30.45, p=0.002). CONCLUSIONS: Anti-SMN aAbs were present in 59% of our MCTD cohort. Their presence, especially at high-titres, was associated with a severe systemic sclerosis (scleroderma) phenotype including myositis, myocarditis and lower GI involvement.

Rare Ischemic Complications of Giant Cell Arteritis: Case Series and Literature Review.

BACKGROUND Some ischemic complications due to giant cell arteritis (GCA) are rare and underdiagnosed. We describe the clinical features and outcomes of patients with GCA presenting with rare ischemic complications. CASE REPORT Our single-center retrospective database of patients with GCA was reviewed from 1994 to 2020. We describe 3 cases of rare ischemic complications secondary to GCA. We review the literature regarding ischemic complications due to GCA and their outcomes. All 3 cases met the American College of Rheumatology criteria for GCA. All patients experienced rare ischemic complications due to GCA. In case 1, the patient presented with a sixth cranial nerve palsy. In case 2, the patient presented with tongue and scalp necrosis, and with permanent visual loss due to anterior ischemic optic neuropathy. In case 3, the patient presented with scalp necrosis. In all 3 cases, the patients received glucocorticoids either intravenously and/or orally, which led to improvement. They all improved within the course of their followup visits. A literature review was performed to identify similar cases and outcomes. CONCLUSIONS Ischemic complications due to GCA can be part of the initial presentation of the vasculitis, making confirmation of the diagnosis more difficult. Physicians should be aware of these rare complications since rapid diagnosis and initiation of glucocorticoids may alter the course of the disease.

Characterization of visual manifestations and identification of risk factors for permanent vision loss in patients with giant cell arteritis.

BACKGROUND/PURPOSE: Permanent vision loss (PVL) is a feared complication and a leading cause of morbidity in giant cell arteritis (GCA). The objective of this study is to describe visual manifestations and identify risk factors of ocular involvement in GCA. METHODS: A retrospective database from a single vasculitis referral center was used. Descriptive statistics comparing patients with and without ocular involvement were performed. RESULTS: One hundred patients with GCA were included. Visual symptoms were present in 53% of patients at diagnosis and included blurred vision (30%), diplopia (16%), amaurosis fugax (14%), and blindness (19%). Out of 19 patients with blindness, 16 did not recover and had PVL. Patients with PVL were older (79.2 ± 6.7 vs 74.2 ± 7.6 years; p = 0.008) and more likely to have coronary artery disease (31% vs 10%; p = 0.018). However, they were less likely to have other cranial symptoms (81% vs 96%; p = 0.019), mainly headaches (64% vs 92%; p = 0.003). Risk factors associated with an abnormal ophthalmologic examination were the same as for PVL, but patients were also more likely to have diabetes (29% vs 7%; p = 0.040) and less likely to have constitutional symptoms (53% vs 80%; p = 0.033). CONCLUSION: Patients with GCA and ocular involvement were more likely to have baseline diabetes and atherosclerosis. A predisposing vascular vulnerability might therefore increase the risk of ocular involvement. Key points • Most patients with GCA and complete vision loss at presentation will not recover and evolve to have permanent vision loss. • A GCA patient with visual manifestations at presentation has more baseline vascular risk factors (diabetes, atherosclerosis) than patients without ocular involvement. • Patients with GCA and visual manifestations have fewer constitutional symptoms and lower inflammatory markers than patients without ocular involvement.