Circulating calprotectin as biomarker in neutrophil-related inflammation: Pre-analytical recommendations and reference values according to sample type.

BACKGROUND: Calprotectin (CLP) is a promising biomarker for the evaluation of neutrophil-related inflammation. Our aim was to establish reference values for circulating CLP in different sample types and to study the effect of pre-analytical variables. METHODS: Reference values were determined in 100 healthy individuals. Pre-analytical variables were evaluated in 10 healthy controls and four rheumatoid arthritis patients with active disease and covered sample type (serum with/without gel separator, heparin, EDTA and citrate plasma), pre-centrifugation time (<2 h, 6 h, 24 h), storage condition (2-8 °C, 18-25 °C, 30 °C) and storage time (24 h, 72 h, 7 days). CLP measurements were performed with the EliA™Calprotectin 2 assay on Phadia™200 (Thermo Fisher Scientific). RESULTS: In healthy controls, baseline CLP concentrations in serum were more than double the concentration in EDTA and citrate plasma (0.909 µg/mL versus 0.259 µg/mL and 0.261 µg/mL respectively). Heparin, EDTA and citrate stabilized CLP concentrations for up to 6 h before centrifugation, whereas significant increases in CLP levels were observed when serum was left untreated during that time period. CONCLUSION: Clinical studies on circulating CLP need to apply sample type-specific reference values and decision limits. To obtain reproducible CLP results in serum, more stringent pre-analytical sample handling instructions are needed.

ASDAS high disease activity versus BASDAI elevation in patients with ankylosing spondylitis as selection criterion for anti-TNF therapy.

OBJECTIVE: To investigate which of the 2 ankylosing spondylitis (AS) disease activity instruments identifies better those patients with characteristics that have been associated with positive response to anti-TNF therapy. METHODS: Data from patients with AS in the REGISPONSER registry were analyzed. Patients were categorized by disease activity using 3 different selection criteria: elevated Bath Ankylosing Spondylitis Disease Activity Index criteria (BASDAI≥4), high Ankylosing Spondylitis Disease Activity Score (ASDAS≥2.1), or very high ASDAS (ASDAS≥3.5). To determine which criterion selects for patients most likely to respond to anti-TNF therapy, the groups of patients selected with each criterion were compared on five disease characteristics that are associated with good response to anti-TNF therapy: lower age, lower function score, less enthesitis, higher C-reactive protein (CRP), and HLA-B27-positive status. RESULTS: 50.9%, 66.3%, and 24.9% of 1156 patients had elevated BASDAI, high ASDAS, or very high ASDAS, respectively. Compared to patients selected with elevated BASDAI, more patients selected with high ASDAS had characteristics associated with good response to anti-TNF therapy. Patients with very high ASDAS had higher CRP and were younger, but more frequently had enthesitis and had higher function scores when compared to those with elevated BASDAI. CONCLUSIONS: Selection of AS patients with the ASDAS instrument results in patient sub-populations with different characteristics than those selected with the BASDAI instrument. Since some of these characteristics have been associated with response to anti-TNF therapy, further study should establish if the choice of selection instrument improves the outcome of therapy in the selected populations.

Predictors of functional impairment and pain in erosive osteoarthritis of the interphalangeal joints: comparison with controlled inflammatory arthritis.

OBJECTIVE: To compare levels of pain and functional limitation in patients with erosive osteoarthritis (OA) of the interphalangeal finger joints with those in patients with nonerosive OA and patients with controlled inflammatory arthritis affecting the hands, and to explore predictors of functional impairment in erosive OA. METHODS: A cross-sectional study including 270 patients with OA of the hands who were referred to rheumatology clinics was performed. A group of patients with inflammatory arthritis (rheumatoid arthritis or psoriatic arthritis) with a low Disease Activity Score in 28 joints (<3.2; n = 79) was examined. Levels of functional impairment (measured by the Functional Index for Hand OA [FIHOA] and Australian/Canadian OA Hand Index [AUSCAN]) and pain were compared between the groups. Predictors of functional impairment in erosive OA were evaluated by generalized linear models. RESULTS: Of 270 patients with hand OA, 167 (61.9%) were classified as having erosive OA. Despite a higher percentage of patients taking analgesics (almost 60%), patients with erosive OA had worse functional outcome and pain scores than patients with controlled inflammatory arthritis or nonerosive OA. Pain scores remained significantly higher in patients with erosive OA after correction for potential confounders. FIHOA and AUSCAN function scores showed a trend toward more disability in patients with erosive OA. Female sex and the number of radiographic affected joints (consisting of joints in the erosive and remodeled radiographic phases) were the strongest predictors of functional impairment in erosive OA. Whether the carpometacarpal joints were affected did not influence functional status in patients with erosive OA. CONCLUSION: Our findings indicate that patients with erosive OA have more functional impairment and significantly more pain compared to patients with controlled inflammatory arthritis affecting the hands. This highlights the significant clinical burden of erosive OA and warrants the search for new treatment strategies.

Clinical observations programme in SpA: disease parameters, treatment options and practical management issues.

Spondyloarthritides (SpAs) are a cluster of chronic inflammatory rheumatic diseases that typically involve inflammation of axial and peripheral joint or tendon and ligament insertions, distinct radiographic changes and diverse extra-articular features. Conventional treatments relieve the signs and symptoms but do not prevent disease progression. TNFalpha inhibitors provide clinicians with the potential to treat the underlying pathology and to alter disease progression. By targeting the underlying inflammatory mechanisms, TNFalpha blockade can treat any extra-articular manifestations of SpA.

Osteochondral repair in synovial joints.

PURPOSE OF REVIEW: One of the major challenges in rheumatology remains the induction of osteochondral repair in synovial joints. Remarkable progress has been made in controlling the inflammatory pathways of chronic synovitis and tissue damage in rheumatoid arthritis and spondyloarthropathy. Here, we provide an overview of the current knowledge on the mechanisms involved in osteochondral repair in degenerative joint diseases, as well as in immune mediated inflammatory arthritides, with special emphasis on tumor necrosis factor alpha and IL-1. RECENT FINDINGS: Homeostasis of articular cartilage and subchondral bone are essential for maintaining the integrity of osteochondral structures within synovial joints. This is achieved by the regulation of a delicate balance between anabolic and catabolic signals. In articular cartilage one cell type, the chondrocyte, is responsible for regulation of homeostasis. In bone, however, two distinct cell types, osteoblasts and osteoclasts, are responsible for anabolic and catabolic pathways, respectively. In inflammatory joint disorders, this tight regulation is profoundly dysregulated, with tumor necrosis factor alpha acting as an important catalyst of a disturbed homeostasis, together with IL-1. Targeting these cytokines may restore the intrinsic repair capacity of osteochondral structures. SUMMARY: To restore catabolic cytokine balances appears to be a suitable strategy to promote osteochondral repair.