Management of psoriatic arthritis from the view of the dermatologist

Psoriatic arthritis (PsA) is an inflammatory seronegative spondyloarthropathy associated with psoriasis. Although the main assessment measures for PsA are borrowed from the standard criteria used to assess rheumatoid arthritis, a number of new criteria such as the PsAJAI and CPDAI are being developed specifically for PsA. Long-term consequences of untreated PsA include persistent inflammation, progressive joint damage and, in many cases, substantial functional limitations, pain and disability. Moreover, patients with PsA have an increased mortality risk and an increased risk of developing cardiovascular disease and metabolic syndrome. Both GRAPPA and the AAD have developed treatment guidelines, which are discussed here. Psoriasis commonly precedes arthritic symptoms; thus, dermatologists are ideally placed to make the initial diagnosis of PsA and treat it appropriately, affording the opportunity to slow disease progression, improve physical function and enhance quality of life. This Review explores the management of patients with PsA, with a particular emphasis on assessment tools, long-term consequences and treatment issues from the viewpoint of the dermatologist.

Synovitis in psoriatic arthritis: immunohistochemistry, comparisons with rheumatoid arthritis, and effects of therapy

Psoriatic arthritis (PsA) is a chronic inflammatory arthropathy associated with psoriasis that affects the peripheral joints, spine, and entheses. Most patients with PsA present with peripheral synovitis of the oligoarticular or polyarticular subtype. As one of the targets of this disease, studies on the synovium may provide insight into the mechanisms involved in this condition. Key findings from the available studies comparing synovial tissue of PsA and rheumatoid arthritis patients are discussed in this review. Also, changes in the synovial infiltrate, expression of proinflammatory cytokines and adhesion molecules, and vascularity in synovial tissue after treatment with various medications are addressed. Finally, a model for proof-of-principle study design using serial synovial biopsies is described, which could be used to predict clinical (in)efficacy in early clinical trial design in PsA.

Co-stimulation modulation with abatacept in patients with recent-onset type 1 diabetes: a randomised, double-blind, placebo-controlled trial

BACKGROUND

The immunopathogenesis of type 1 diabetes mellitus is associated with T-cell autoimmunity. To be fully active, immune T cells need a co-stimulatory signal in addition to the main antigen-driven signal. Abatacept modulates co-stimulation and prevents full T-cell activation. We evaluated the effect of abatacept in recent-onset type 1 diabetes.

METHODS

In this multicentre, double-blind, randomised controlled trial, patients aged 6-45 years recently diagnosed with type 1 diabetes were randomly assigned (2:1) to receive abatacept (10 mg/kg, maximum 1000 mg per dose) or placebo infusions intravenously on days 1, 14, 28, and monthly for a total of 27 infusions over 2 years. Computer-generated permuted block randomisation was used, with a block size of 3 and stratified by participating site. Neither patients nor research personnel were aware of treatment assignments. The primary outcome was baseline-adjusted geometric mean 2-h area-under-the-curve (AUC) serum C-peptide concentration after a mixed-meal tolerance test at 2 years' follow-up. Analysis was by intention to treat for all patients for whom data were available. This trial is registered at ClinicalTrials.gov, NCT00505375.

FINDINGS

112 patients were assigned to treatment groups (77 abatacept, 35 placebo). Adjusted C-peptide AUC was 59% (95% CI 6·1-112) higher at 2 years with abatacept (n=73, 0·378 nmol/L) than with placebo (n=30, 0·238 nmol/L; p=0·0029). The difference between groups was present throughout the trial, with an estimated 9·6 months' delay (95% CI 3·47-15·6) in C-peptide reduction with abatacept. There were few infusion-related adverse events (36 reactions occurred in 17 [22%] patients on abatacept and 11 reactions in six [17%] on placebo). There was no increase in infections (32 [42%] patients on abatacept vs 15 [43%] on placebo) or neutropenia (seven [9%] vs five [14%]).

INTERPRETATION

Co-stimulation modulation with abatacept slowed reduction in β-cell function over 2 years. The beneficial effect suggests that T-cell activation still occurs around the time of clinical diagnosis of type 1 diabetes. Yet, despite continued administration of abatacept over 24 months, the decrease in β-cell function with abatacept was parallel to that with placebo after 6 months of treatment, causing us to speculate that T-cell activation lessens with time. Further observation will establish whether the beneficial effect continues after cessation of abatacept infusions.

FUNDING

US National Institutes of Health.

The expression and distribution of immunomodulatory proteins B7-H1, B7-DC, B7-H3, and B7-H4 in rheumatoid synovium

CD28/B7 signals have been shown to have the capacity to regulate T cell activation and participate in regulating the development of rheumatoid arthritis (RA). However, the expression and anatomical distribution of some members of the B7 superfamily including B7-H1, B7-DC, B7-H3 and B7-H4 in RA synovium is still unclear. We analyzed the expression of these molecules in synovial tissues from RA patients. Immunohistochemistry showed that all of these molecules were observed in synovium. On the cellular level, all of them were found on cell membrane and in cytoplasma. The expression of B7-DC and B7-H3 was major on capillaries, synovicytes and infiltrated inflammatory cells in the lining layer, while B7-H1 and B7-H4 were detected in some inflammatory cells residing in the sublining and lining layer. Fluorescent dual staining indicated that all these molecules were principally associated with CD31(+) endothelial cells and CD68(+) macrophages. In addition, B7-H1 and B7-H3 were also observed on CD3(+) T cells (including CD4(+) and CD8(+) T cells). Interestingly, B7-H1/B7-H4, B7-H3/B7-DC were co-expressed on the same cells. The characteristic expression and distribution of these molecules in synovium indicated that they probably have different effects during the progress of RA, and a clear understanding of their functional roles may further elucidate the pathogenesis of this disease.

Autoimmune therapies targeting costimulation and emerging trends in multivalent therapeutics

Proteins participating in immunological signaling have emerged as important targets for controlling the immune response. A multitude of receptor-ligand pairs that regulate signaling pathways of the immune response have been identified. In the complex milieu of immune signaling, therapeutic agents targeting mediators of cellular signaling often either activate an inflammatory immune response or induce tolerance. This review is primarily focused on therapeutics that inhibit the inflammatory immune response by targeting membrane-bound proteins regulating costimulation or mediating immune-cell adhesion. Many of these signals participate in larger, organized structures such as the immunological synapse. Receptor clustering and arrangement into organized structures is also reviewed and emerging trends implicating a potential role for multivalent therapeutics is posited.