C-reactive protein and outcome after ischemic stroke.

BACKGROUND AND PURPOSE: Elevated concentrations of the acute-phase reactant C-reactive protein (CRP) predict ischemic cardiac events in both hospital- and population-based studies and may signify a role for inflammation in the destabilization of cardiovascular disease. We examined the relationship between CRP and outcome after acute ischemic stroke. METHODS: This was a subgroup analysis from a prospective observational study based in a University Hospital Acute Stroke Unit serving a population of approximately 260 000. Survival time and cause of death for up to 4 years after the index stroke were determined and related to CRP concentration within 72 hours of stroke and known prognostic variables by a Cox proportional hazards regression model. RESULTS: Ischemic stroke was diagnosed in 228 of 283 consecutive admissions. Median follow-up was 959 days. Geometric mean CRP concentration was 10.1 mg/L. Survival in those with CRP >10.1 mg/L was significantly worse than in those with CRP 10.1 mg/L and 63% of deaths in those with CRP

Anticardiolipin antibodies in an unselected stroke population.

A pathogenetic role in thrombotic disease, particularly in young people, has been postulated for anticardiolipin antibody (ACA). We have carried out a prospective controlled study of 262 unselected patients with acute stroke and 226 controls to assess the prevalence and relation to age and vascular risk factors of ACA. Titres of IgG, IgA, or IgM ACA were above the upper normal limit in 38% of patients. The proportions of patients and controls with raised titres did not differ significantly (13 vs 8% IgG, 22 vs 29% IgA, 11 vs 7% IgM). IgG titres were higher among patients than among controls (mean 3.88 vs 2.86 u/mL [95% CI for difference 0.62-0.87], p = 0.0004), whereas IgA and IgM titres were lower in patients than in controls (IgA 4.82 vs 5.98 u/mL [1.12-1.60], p = 0.01; IgM 3.00 vs 3.64 u/mL [1.01-1.45], p = 0.04). However, within age tertiles the only significant difference between patients and controls for IgG ACA was in the oldest tertile. Analysis by number of risk factors for stroke showed a significant difference between the groups only for subjects with one risk factor. IgA and IgM ACA titres were higher among controls only in those with no vascular risk factors. We found no evidence to support the hypothesis that ACA is an independent risk factor for stroke in young people. The increase in IgG titre with age and number of vascular risk factors in stroke patients suggests that ACA may be a non-specific accompaniment of vascular disease. Routine testing for ACA in stroke patients is not justified.

Distinct types of lung disease caused by functional subsets of antiviral T cells.

T cells appear to play a central role in viral bronchiolitis, but the effects of different functional and phenotypic subgroups of T cells have not been defined. To test the activities of T cells recognizing individual proteins of respiratory syncytial (RS) virus, virus-specific T cell lines were produced from mice primed by scarification with recombinant vaccinia viruses expressing the major surface glycoprotein (G), fusion protein (F) or second matrix (22K) protein of RS virus. As previously reported, the in vitro characteristics of these cells are predetermined by the choice of RS virus protein: 22K-specific cells are predominantly class I-restricted cytolytic CD8+ cells; F-specific cells, a mixture of cytolytic CD8+ cells and CD4+ cells with a T helper 1 cell (Th1) cytokine secretion profile, whereas those from G-sensitized mice are almost exclusively CD4+, with Th2 characteristics. Mice infected intranasally with RS virus showed mild illness and recovered fully, but developed respiratory distress after intravenous injections of T cells. Dose-for-dose, infected mice receiving G-specific cells suffered the most severe (sometimes fatal) illness, characterized by lung hemorrhage, pulmonary neutrophil recruitment (shock lung) and intense pulmonary eosinophilia. This disease was further enhanced by coinjection of 22K-specific cells, which alone caused mild shock lung without eosinophilia. F-specific cells caused minimal enhancement of pathology and had little or no effect on the disease caused by G-specific cells. Each cell line reduced lung virus titer and combined injections of G- and 22K-specific cells eliminated infection completely. The in vitro characteristics of these antiviral T cell lines therefore predict the pathological effects in vivo. Moreover, different forms of viral bronchiolitis can be caused by functionally distinct types of activated T cell.

Phenotypic and functional characterization of T cell lines specific for individual respiratory syncytial virus proteins.

Mice sensitized to individual respiratory syncytial (RS) virus proteins show distinct patterns of immunity and pulmonary pathology when challenged with live virus. To explore the immune mechanisms responsible for the differences in postvaccination disease, BALB/c (H-2d) mice were primed by scarification with recombinant vaccinia viruses (rVV) expressing the major glycoprotein (G), fusion protein (F), phosphoprotein (P), nucleoprotein (N), or second matrix (22K) protein of RS virus. Ag-stimulated spleen cell cultures gave rise to CD3+TCR-alpha beta + T cell lines. Those from rVV-F-primed mice contained a mixture of CD8+ and CD4+ T cells, whereas those specific to G, N, and P were mostly CD4+. In contrast, 22K-specific lines were mostly CD8+. F- and 22K-specific lines showed virus-specific CTL activity against H-2d targets, but the lines from rVV-G-, -N-, and -P-primed mice did not. The F-specific lines contained Th cells that released an excess of IL-2 and some IL-3 but little IL-4 or IL-5 (i.e., a "Th1" pattern). In contrast, the G-specific line released IL-3, IL-4, and IL-5 but little IL-2 (i.e., a "Th2" pattern). The 22K line contained IL-3-releasing T cells. Staining of T cell subsets for CD45RB varied in intensity in different lines, consistent with the cytokine secretion profiles of the Th cells that they contained. Because different RS virus proteins (given in the same form by the same route) prime for functionally different T cells, the ways in which individual proteins are processed and presented might be important in determining these patterns of immunity.

T-cell-mediated response in Dupuytren's disease.

The cause of Dupuytren's disease is unknown, but inflammatory cells might have a role. Enzymatic digestion of diseased tissue permits identification and immunofluorescent labelling of a cell subset displaying inflammatory cell morphology. Cytofluorimetry of this cell population demonstrated the presence of CD3-positive lymphocytes and expression of major histocompatibility complex (MHC) class II proteins. These results raise the possibility that Dupuytren's disease is a T-cell-mediated autoimmune disorder. The development of medical treatment on this basis may reduce the need for surgery, with its associated morbidity and high recurrence rates.

Distinct patterns of T- and B-cell immunity to respiratory syncytial virus induced by individual viral proteins.

Mice were infected with respiratory syncytial (RS) virus or with recombinant vaccinia viruses (rVV) expressing individual RS virus proteins. rVV-G, rVV-F and, to a lesser extent, rVV-P induced ELISA-binding anti-RS virus antibodies; those induced by rVV-P were non-neutralizing. Different antigens induced helper T cells with distinct cytokine secretion profiles: some released IL-2, and others predominantly IL-4 and 5. Virus-specific cytotoxicity was induced by infection with RS virus, rVV-F or rVV-22K. Different RS virus proteins (given in the same route and form) therefore prime for functionally distinct T-cell activities. These patterns of virus-specific immunity may help explain the pathogenicity of RS virus vaccines, and help in the design of protective, non-pathogenic vaccines in the future.

CD4+ T cells clear virus but augment disease in mice infected with respiratory syncytial virus. Comparison with the effects of CD8+ T cells.

Respiratory syncytial (RS) virus-specific T cell lines were derived from the spleens of BALB/c mice primed by intranasal infection with RS virus. The lines were expanded by repeated antigenic stimulation in vitro, and separated into CD4+ and CD8+ T cell-enriched fractions by immunomagnetic adhesion. The effects of passive transfer of these fractions into RS virus infected mice were observed. The most severe immunopathological changes were seen in mice receiving CD4+ cells. Transfer of CD4+, CD8+ or both cell fractions caused RS virus-infected mice to become ill and lose weight. Both cell lines caused an increase in the severity of lung pathology (as monitored by bronchoalveolar lavage) with the appearance of lung haemorrhage and polymorphonuclear cell efflux. In addition, recipients of CD4+ cells developed striking pulmonary eosinophilia. In CD4+ cell recipients, 5 x 10(5) cells were sufficient to decrease lung virus titre, whereas 2 x 10(6) CD8+ cells were needed to produce a similar effect. The unseparated T cell line and the CD4+ cell fraction secreted significant amounts of IL-3, IL-4 and IL-5 (P less than 0.001). High levels of IL-2 were produced only by the unseparated T cell line. The CD8+ cell fraction secreted IL-3 only. The results show that, cell-for-cell, CD4+ cells are more anti-viral and more immunopathogenic than CD8+ cells in RS virus infected mice. Such effects may have contributed to the augmented disease seen in some infants vaccinated against RS virus.

Interleukin-1-like activity in synovial fluids and sera of horses with arthritis.

Synovial fluid samples of horses with osteoarthritis were investigated to detect interleukin-1 (IL-1) activity which could contribute to the disease pathogenesis. Of the 32 samples tested, 12 (37.5 per cent) showed an augmented phytohaemagglutinin induced proliferation of C3H/HeJ mouse thymocytes. Positive results were also seen in horses with infected arthritis, osteochondritis, traumatic arthritis and undefined synovial effusions. Normal synovial fluid and sera from all groups failed to show any detectable IL-1 activity. Fractionation of synovial fluid showed that the IL-1 activity was in the 15 to 20 Kd fractions. In the absence of mitogen, synovial fluid failed to stimulate thymocytes and did not stimulate the growth of an interleukin-2 (IL-2) dependent CTLL cell line, but synovial fluid stimulated IL-2 release by mouse spleen cells incubated with suboptimal doses of lectin. Evidence of an IL-1 inhibitor in synovial fluid from osteoarthritic horses was provided by ultrafiltration experiments and by the inhibitory activity of synovial fluid at particular dilutions in the thymocyte assay. The presence of IL-1-like activity could be relevant in the pathogenesis of arthritis in horses.

Glycosaminoglycans in horses with osteoarthritis.

Horse articular cartilage glycosaminoglycans (GAGs) were measured in synovial fluids from 48 joints affected with osteoarthritis (OA), 22 normal joints, four joints with osteochondritis, three joints with traumatic arthritis and seven joints infected with bacteria. Serum and urine from individual horses were also examined for the presence of GAGs. High levels of GAGs were found in synovial fluids (SF) from horses with OA. In each case, the level was higher in the synovial fluid than in the serum or urine from the same horse. Horses with OA showed high GAG levels in SF, serum and urine compared to horses with normal and infected joints. High levels were also found in horses with osteochondritis and traumatic arthritis. Levels of synovial fluid GAG reflect cartilage destruction in arthritis and may be useful for monitoring disease progression in the equine species.

Cartilage breakdown in equine osteoarthritis: measurement of keratan sulphate by an ELISA system.

Degradation of cartilage in osteoarthritis of man results in the release of sulphated glycosaminoglycans, particularly keratan sulphate, into tissue fluids. A study was made to evaluate these markers for osteoarthritis in the horse. Synovial fluid and serum levels of keratan sulphate, measured by an ELISA-inhibition technique, and sulphated glycosaminoglycans measured by specific dye binding assay, were found to be significantly increased (P less than 0.001) in joints from horses with osteoarthritis, compared with normal joints. Synovial fluids from joints with infective arthritis also showed high keratan sulphate levels, but statistically were not significantly different from osteoarthritis. Measurement of serum/synovial fluid levels of proteoglycan may enable cartilage degeneration to be detected and monitored and help more effective treatments to be developed in the equine species.

Hydroxyapatite and urate crystal induced cytokine release by macrophages.

Destructive osteoarthritis is characterised by rapidly progressive joint destruction associated with intra-articular deposition of hydroxyapatite crystals. The possible role of such crystals in the pathogenesis of this condition was investigated by testing the ability of hydroxyapatite crystals to stimulate the production of bone resorbing activity from mouse peritoneal macrophages. Urate crystals were used for comparison. Culture supernatants were tested for bone resorbing activity using the mouse calvarial bone resorption assay, for interleukin 1 using a standard lymphocyte activation assay, and for prostaglandin E2 by radioimmunoassay. Culture supernatants from macrophages incubated with hydroxyapatite crystals contained dialysable bone resorbing activity, high concentrations of prostaglandin E2, but no interleukin 1 like activity. The production of the bone resorbing agent was prevented by culturing macrophages with hydroxyapatite crystals in the presence of indomethacin. By contrast, culture supernatants from macrophages incubated with urate crystals contained bone resorbing activity, which was only partly removed by dialysis, and interleukin 1 like activity. The latter was shown to be increased in culture supernatants from macrophages incubated with urate crystals in the presence of indomethacin, while production of bone resorbing activity was partially inhibited. It is considered that the bone resorbing activity liberated from macrophages stimulated by hydroxyapatite crystals can be explained by the presence of prostaglandin E2 alone, whereas the activity liberated by urate crystals is due to both prostaglandin E2 and interleukin 1.

Idiopathic destructive arthritis of the shoulder.

IDA of the shoulder is a condition found predominantly in elderly females. Although the shoulder is primarily involved, other joints such as the hip and knee can be affected, and concurrent OA is common at other joint sites. Clinical features include voluminous, often blood-stained effusions, together with features of rotator cuff rupture and restriction of shoulder movement. Laboratory parameters are usually normal and examination of the synovial fluid reveals large amounts of basic calcium phosphate crystals. The synovium is hypertrophied and vascular and shows fibrin deposition. It contains calcified material extracellularly. An acute inflammatory infiltrate is absent. Radiographs demonstrate soft tissue swelling and subchondral sclerosis with marked bony attrition involving the acromioclavicular and glenohumeral joints, as well as the humeral head and neck. Although some aspects of the disease seem distinct, many features are shared with other types of destructive arthritis of the shoulder. The pathogenesis of this disorder is at present obscure, but it is clear that an understanding of the processes involved will provide a vital contribution to our understanding of the response of the joint to insult. With a multidisciplinary approach and adequate communication between interested workers this aim could seen be within our grasp.

Bone resorbing activity in synovial fluids in destructive osteoarthritis and rheumatoid arthritis.

The synovial fluids of patients with a destructive form of osteoarthritis (DOA) were shown to contain high levels of bone resorbing activity as judged by the ability of the fluid to stimulate the release of 45Ca from labelled cultured mouse calvariae. The activity was lost on extended storage of the synovial fluids and was dependent for its effect on cellular activity in bone. Bone resorbing activity was present in most synovial fluids from patients with DOA and rheumatoid arthritis (RA) but occurred at higher levels in the former. In contrast, interleukin 1 (IL1) activity, measured by the mouse thymocytes costimulation assay, was higher in RA than DOA synovial fluids. Little or no bone resorbing or IL1 activity was detected in synovial fluids from patients with pseudogout or non-destructive osteoarthritis. These results suggest that most DOA synovial fluids contain a bone resorbing factor other than IL1. It is considered that the factor may be produced by synovial cells stimulated by hydroxyapatite crystals.