Immune function in patients with rheumatoid arthritis treated with etanercept.

Etanercept, a recombinant human tumor necrosis factor (TNF) inhibitor that binds both soluble and cell-bound TNF, has been shown to reduce disease activity and inhibit joint destruction when administered to patients with rheumatoid arthritis (RA). Because TNF receptors are found on many types of cells that modulate the immune response, we evaluated the general immune function of a subset of RA patients in a blinded clinical study. No significant differences were seen between patients treated with etanercept or placebo in the surface antigen phenotypes of peripheral blood leukocytes, T cell proliferative responses, neutrophil function, delayed-type hypersensitivity (DTH) reactions, serum immunoglobulin levels, or incidence of infections. Although this observational study was relatively small and could detect only major changes in immunological status, the stability of immune function over time in patients receiving etanercept corroborates the findings in clinical studies, which suggest that etanercept does not alter overall global immune function.

Etanercept (Enbrel): update on therapeutic use.

Tumour necrosis factor (TNF) is an important inflammatory disease mediator in a wide spectrum of articular diseases, including adult and juvenile rheumatoid arthritis (RA, JRA). Etanercept (Enbrel), approved in the United States and in Europe for use in patients with RA and JRA, is an effective inhibitor of TNF that has been shown to provide rapid and sustained improvement in both of these diseases. Long term studies continue to show that etanercept controls signs and symptoms of RA and JRA with no change in rate or type of adverse event over time. To demonstrate that etanercept is effective as first line treatment for patients with early active RA who have not been previously treated with methotrexate, and to examine the effect of etanercept on radiographic progression, a double blind, placebo controlled study was recently conducted, comparing etanercept with methotrexate (median dose 20 mg per week). Both etanercept 25 mg twice weekly and rapidly escalated methotrexate were effective in reducing the signs and symptoms of RA, and etanercept was significantly better than methotrexate in slowing the rate of radiographic erosions. In patients with severe psoriatic arthritis (PsA), a double blind, placebo controlled study demonstrated that etanercept was also effective in reducing disease activity in PsA. Etanercept has been well tolerated in all of these clinical trials and offers an important new treatment option to patients with inflammatory articular diseases.

Vascular permeability factor/endothelial growth factor (VPF/VEGF): accumulation and expression in human synovial fluids and rheumatoid synovial tissue.

Vascular permeability factor (VPF, also known as vascular endothelial growth factor or VEGF), is a potent microvascular permeability enhancing cytokine and a selective mitogen for endothelial cells. It has been implicated in tumor angiogenesis and ascites fluid accumulation. Since development of the destructive synovial pannus in rheumatoid arthritis (RA) is associated with changes in vascular permeability (synovial fluid accumulation), synovial cell hyperplasia, and angiogenesis, we examined synovial fluids (SFs) and joint tissue for the expression and local accumulation of VPF/VEGF. VPF/VEGF was detected in all of 21 synovial fluids examined and when measured by an immunofluorimetric assay, ranged from 6.9 to 180.5 pM. These levels are biologically significant, since < 1 pM VPF/VEGF can elicit responses from its target cells, endothelial cells. Levels of VPF/VEGF were highest in rheumatoid arthritis fluids (n = 10), with a mean value (+/- SEM) of 59.1 +/- 18.0 pM, vs. 21.4 +/- 2.3 pM for 11 SFs from patients with other forms of arthritis (p = 0.042). In situ hybridization studies that were performed on joint tissues from patients with active RA revealed that synovial lining macrophages strongly expressed VPF/VEGF mRNA, and that microvascular endothelial cells of nearby blood vessels strongly expressed mRNA for the VPF/VEGF receptors, flt-1 and KDR. Immunohistochemistry performed on inflamed rheumatoid synovial tissue revealed that the VPF/VEGF peptide was localized to macrophages within inflamed synovium, as well as to microvascular endothelium, its putative target in the tissue. Together, these findings indicate that VPF/VEGF may have an important role in the pathogenesis of RA.

Retinoic acid effects on endothelial cell function: interaction with interleukin 1.

Blood vessel angiogenesis is an important component of chronic synovitis, and its regulation may be mediated through local production and effects of certain inflammatory cytokines, including interleukin-1 (IL-1). Retinoic acid (RA) can alter the progression of some inflammatory arthritic diseases, presumably through effects on fibroblast collagenase and PGE2 production. To explore alternate hypotheses, we examined the interaction of retinoic acid and IL-1 on endothelial cell (EC) function and found that RA directly affects and modifies the effects of IL-1 on EC proliferation, prostacyclin production, and plasminogen activator inhibitor capacity (PAI-1). With respect to EC proliferation, cis- and trans-retinoic acid and retinol induced a dose-dependent increase of [3H]TdR uptake by cultured ECs, independent of the effects of serum or eicosanoid production. This effect was blocked by IL-1. With respect to EC prostacyclin production, although retinoic acid alone had no effect, cis and trans-retinoic acid and retinol all induced a dose-dependent increase in IL-1-mediated prostacyclin production, which was most marked at higher concentrations (20 U/ml) of IL-1. This effect was mediated through effects independent of cyclooxygenase (COX) production. With respect to plasminogen activator inhibitor capacity, both IL-1 and retinoic acid stimulated EC PAI-1 synthesis, but the individual effects were additive, with RA augmenting the known IL-1 effects on EC PAI-1 production. The interaction between RA and IL-1 on the endothelium, described in this study, may play a role in the fashion through which retinoic acid alters the expression of synovitis in certain types of experimental inflammatory arthritis.

Vascular steal mimicking compression myelopathy in Paget's disease of bone: rapid reversal with calcitonin and systemic steroids.

Neurologic manifestations of Paget's disease of bone are primarily a result of mechanical compression on cranial nerves, spinal cord and roots. Less recognized is a myelopathy from "vascular steal" to highly vascularized and hypermetabolic pagetic bone. We describe a case of presumed ischemic myelitis in a patient with Paget's disease and aortic stenosis that was rapidly reversed with subcutaneous calcitonin and intravenous dexamethasone.

Augmentation of interleukin-1 induced prostacyclin production by endothelial cell growth factor: implications for chronic synovitis.

Interleukin-1 (IL-1) is a key inflammatory cytokine that has important effects both on endothelial cell (EC) growth and synthetic function. Fibroblast growth factors (FGF's), including endothelial cell growth factor (ECGF), are important regulators of EC growth, and their role in the pannus formation and synovial proliferation seen in chronic arthritis has been emphasized recently. While ECGF mediated EC proliferation is inhibited by IL-1, potential interaction of these peptides on other aspects of EC function has not been described. As both IL-1 and FGF may be important disease mediators in rheumatoid arthritis, we studied their combined effects on EC prostacyclin production. While ECGF alone had no measurable effects, it enhanced rIL-1 alpha induced prostacyclin production in a dose and time dependent fashion. Both pertussis and cholera toxins blocked the augmentation, suggesting a role for G proteins in mediating the synergism. These studies demonstrate that ECGF can alter certain effects of IL-1 on the endothelium, and point to an additional role that this family of growth factors may play in some inflammatory disorders.

T-lymphocyte subset phenotypes: a multisite evaluation of normal subjects and patients with AIDS.

The present study was undertaken to determine normal ranges for blood lymphocytes labeled with the monoclonal antibodies OKT3, OKT11, OKT4, and OKT8 and for the OKT4/OKT8 ratio. In addition, 26 patients with AIDS, 51 AIDS suspects, and 44 patients with infections were studied. The results of these determinations from six different study sites indicate that there is excellent intersite agreement in normal values obtained. These normal ranges may be used in clinical laboratory reporting. Data from patients indicate that a simultaneous review and comparison of OKT4+ values, OKT8+ values, and depression of the OKT4+/OKT8+ ratio is a useful indicator in clinically diagnosed AIDS patients and in AIDS suspects. These changes, moreover, cannot be attributed only to infection present in these patients, since in infection, the OKT4+/OKT8+ ratio does not exhibit the severe depression seen in AIDS. These results should provide a useful reference for further studies in diseased subjects.

Nailfold capillary abnormalities in childhood rheumatic diseases.

The nailfold capillary patterns of 84 patients with a variety of childhood rheumatic diseases and 34 normal control subjects were observed. Distinctive morphologic abnormalities with capillary dilation and dropout of surrounding structures were noted in two groups: patients with childhood dermatomyositis and with scleroderma (P less than 0.001). Among those with scleroderma, capillary abnormalities were found in all nine patients with systemic disease and in none of 10 patients with cutaneous disease only (Fisher's exact P less than 0.001). Of 25 patients with dermatomyositis for whom muscle biopsies were available for analysis, abnormal nailfold capillary pattern was found with highest prevalence in patients with two or more specific vascular lesions noted on biopsy (Fisher's exact P = 0.041). Nailfold capillary abnormalities are present in distinct populations of childhood rheumatic diseases, reflect the underlying vasculopathy of childhood dermatomyositis, and may be of diagnostic value in distinguishing localized from systemic scleroderma.

A multicenter study of outcome in systemic lupus erythematosus. II. Causes of death.

Causes of death were examined for 1,103 systemic lupus erythematosus patients who were followed from 1965 to 1978 at 9 centers that participated in the Lupus Survival Study Group. A total of 222 patients (20%) died. Lupus-related organ system involvement (mainly active nephritis) and infection were the most frequent primary causes of death. Causes of death were similar throughout the followup period. Hemodialysis had little impact on the length of survival for patients with nephritis. Active central nervous system disease and myocardial infarction were infrequent causes of death. There were no deaths from malignancy.