Multicentre study to improve clinical interpretation of rheumatoid factor and anti-citrullinated protein/peptide antibodies test results.

BACKGROUND: Rheumatoid factor (RF) and anti-citrullinated protein/peptide antibodies (ACPA) are important biomarkers for diagnosis of rheumatoid arthritis (RA). However, there is poor harmonisation of RF and ACPA assays. The aim of this study was to refine RF and ACPA interpretation across commercial assays. MATERIALS AND METHODS: Six total RF isotype-non-specific assays, 3 RF IgM isotype-specific assays and 9 ACPA immunoglobulin G assays of 13 different companies were evaluated using 398 diagnostic samples from patients with RA and 1073 disease controls. RESULTS: Using cut-offs proposed by the manufacturer, there was a large variability in diagnostic sensitivity and specificity between assays. Thresholds of antibody levels were determined based on predefined specificities and used to define test result intervals. Test result interval-specific likelihood ratios (LRs) were concordant across the different RF and ACPA assays. For all assays, the LR for RA increased with increasing antibody level. Higher LRs were found for ACPA than for RF. ACPA levels associated with LRs >80 were found in a substantial fraction (>22%) of patients with RA. CONCLUSION: Defining thresholds for antibody levels and assigning test result interval-specific LRs allows alignment of clinical interpretation for all RF and ACPA assays.

Risk factors for severe cranial ischaemic complications in giant cell arteritis.

OBJECTIVES: Vision complications and a stroke represent severe cranial ischaemic complications (sCIC) associated with increased morbidity and mortality in GCA. We aimed to determine the risk factors for sCIC in GCA. METHODS: We analysed the medical records of prospectively enrolled GCA patients diagnosed between September 2011 and August 2019, and compared the clinical and laboratory characteristics of patients with and without sCIC defined as either severe vision complications (diplopia, transient vision loss, permanent partial vision field/acuity defect and permanent visual loss) or stroke. RESULTS: During the 96-month observation period, we identified 295 new GCA patients [65.4% female, median (interquartile range) age 74.7 (67.3-80.0) years]. Sixty-one (20.7%) patients developed sCIC (52 isolated severe vision complications, 5 isolated ischaemic strokes and 4 patients with both complications). In a multivariable logistic regression model jaw claudication [odds ratio (OR) 3.43 (95% CI: 1.84, 6.42), P < 0.001], smoking [OR 1.92 (95% CI: 1.01, 3.65), P = 0.046] and increasing age [OR 1.08 (95% CI: 1.04, 1.13), P < 0.001] were significantly associated with sCIC. Higher CRP [OR 0.99 (0.99-1.00), P = 0.011] decreased the risk of sCIC. When considered separately, the odds for severe vision complications increased with age and jaw claudication, and decreased with polymyalgia rheumatica, constitutional symptoms and higher CRP. Atrial fibrillation emerged as the sole independent predictor of ischaemic stroke. CONCLUSION: Increasing age, jaw claudication and smoking predicted sCIC, while higher CRP decreased the risk of sCIC in our GCA cohort.

The incidence of giant cell arteritis in Slovenia.

Giant cell arteritis (GCA) is the most common vasculitis in adults aged ≥ 50 years in Europe. Recently, colour Doppler ultrasonography (CDS) and positron emission tomography-computed tomography (PET/CT) have improved the diagnostic sensitivity. The aim of our study was to determine the incidence of GCA in a well-defined Slovenian region, supported by the temporal artery (TA) biopsy (TAB) or CDS or PET/CT. This prospective study was conducted at the University Medical Centre Ljubljana, the only secondary/tertiary centre in the region, serving a population of 323,297 residents aged ≥ 50 years. Patients with suspected GCA are referred either to the Department of Rheumatology, or in case of severe visual disturbances, to the Department of Ophthalmology. We included all GCA cases diagnosed between 1 January 2012 and 31 December 2017. We diagnosed cranial GCA (c-GCA) using the American College of Rheumatology (ACR) 1990 classification criteria and a positive TAB or TA-CDS. Large vessel GCA (lv-GCA) was diagnosed using CDS or PET/CT. During the 6-year observation, we identified 169 incipient GCA cases (66.3% female, median (IQR) age of 75.1 (68.6-80.0) years). Forty-two (24.8%) patients had lv-GCA, and the others had c-GCA. The estimated annual incidence rates of GCA were overall 8.7 (95% CI 7.5-10.1), c-GCA 6.5 (95% CI 5.5-7.8) and lv-GCA 2.2 (95%CI 1.6-2.9) per 100,000 aged ≥ 50 years. GCA is the most common vasculitis in adults aged ≥ 50 years, with an annual incidence rate of 8.7 per 100,000.

The role of colour doppler ultrasonography of facial and occipital arteries in patients with giant cell arteritis: A prospective study.

OBJECTIVE: Colour Doppler Sonography (CDS) in giant cell arteritis (GCA) allows the study of involvement of cranial arteries other than the temporal arteries, which are inconvenient to biopsy, such as the facial (FaA), and occipital (OcA) arteries. We aimed to estimate the frequency of the FaA, and OcA involvement in GCA; and to explore the clinical characteristics of these subgroups of patients. METHODS: From 1 January 2014 to 31 December 2016 we prospectively performed a CDS of the FaA, and OcA in addition to the temporal (TA), and the extracranial supra-aortic arteries in all newly diagnosed patients suspected of having GCA. All the arteries were evaluated in two planes for the highly specific halo sign. RESULTS: During the 36-month observation period we performed a CDS of the cranial and extra-cranial arteries in 93 GCA patients. We observed the halo sign on the FaA, and OcA in 38 (40.9%), and 29 (31.2%) cases, respectively. The FaA, or OcA were affected in 4/22 (18.2%) patients with a negative TA CDS. FaA involvement significantly correlated with jaw claudication and with severe visual manifestations, including permanent visual loss. CONCLUSIONS: A fifth of patients with a negative CDS of the TAs had signs of vasculitis on the CDS of the FaA, or OcA. The addition of FaA and OcA CDS to the routine CDS of the TAs could identify 4.3% more patients and thus further improve the sensitivity of the CDS in the suspected GCA.

A case of inverse psoriasis successfully treated with adalimumab.

Inverse psoriasis is a rare form of psoriasis characterized by the involvement of skin fold areas rather than the more common psoriatic involvement of the extensor surfaces of the extremities, trunk, and scalp. In addition, it requires a modified therapeutic approach because it is often less responsive to standard treatment regimens. Current treatment recommendations for inverse psoriasis mainly consist of topical agents, including corticosteroids, calcipotriol, and immunomodulating agents, whereas systemic medications remain insufficiently studied. Although adalimumab, a TNF-α inhibitor, has been approved for the treatment of moderate to severe plaque psoriasis, some reports indicate that TNF-α inhibitors may sometimes trigger psoriatic lesions, including inverse psoriasis. However, we present a case of inverse psoriasis and psoriatic arthritis unresponsive to standard treatment that was successfully treated with adalimumab.