摘要:

In patients with rheumatoid arthritis, chronic inflammation in affected joints may lead to the development of tertiary lymphoid tissue. A micro-environment is generated in the synovial membrane which supports the activation and differentiation of B cells into plasma cells. Through a process of affinity maturation, plasma cells may be generated locally which secrete antibodies of high affinity. Rheumatoid arthritis is characterised by autoantibodies specific for self immunoglobulin. These rheumatoid factors form large antigen/antibody complexes which may enhance the process of joint destruction. The poor prognosis of rheumatoid factor-positive patients is indicitive of the critical role of immunoglobulin complexes in the continuous stimulation of the immune system and thus of the inflammatory processes. In general, treatment of patients with rheumatoid arthritis aims at suppressing inflammation. The currently most successful reagents are those which interfere with the network of cytokines, such as tumour necrosis factor or interleukin-1 receptor antagonists. Only recently have immunosuppressive therapies targeted directly at the B cell response been developed. These first studies suggest that therapies which directly affect the humoral immune response are of great therapeutic potential in the treatment of patients with rheumatoid arthritis.

ISSN:1173-8804    

出版商:ADIS    

年代:2001

数据来源: ADIS

摘要:

Metabolism of arachidonic acid via the 5-lipoxygenase (5-LO) pathway leads to the formation of hydroperoxyeicosatetraenoic acids (HPETEs) and leukotriene (LT) A4. This unstable allylic epoxide can be further converted by secondary enzymes into LTB4and cysteinyl LTs. LTs represent a family of potent biologically active compounds synthesised by specific cell types and by transcellular biosynthetic mechanisms. Cysteinyl LTs are involved in the pathogenesis of asthma, and recent data indicate that individuals with asthma may have enhanced basal excretion of urinary LTE4compared with normal individuals.Tocopherol (vitamin E) and tocopherol acetate strongly inhibit potato 5-LO in an irreversible and noncompetitive way, and, by affecting the redox state of cells possessing 5-LO, they may influence the production of biologically active LTs. It has been reported that normal plasma levels of tocopherol may enhance the lipoxygenation of arachidonic acid, whereas higher tocopherol levels exert a suppressive effect that is consistent with its role as a hydroperoxide scavenger.Receptor-mediated activation of neutrophils in individuals with asthma results in the synthesis of LTs. This activation is inhibited by tocopherol in a concentration-dependent manner. Additional controlled studies are needed to assess the effect of tocopherol on leukotriene production in asthmatic individuals. The results of these studies may be useful in developing new therapeutic approaches in asthmatic/allergic patients.

ISSN:1173-8804    

出版商:ADIS    

年代:2001

数据来源: ADIS

摘要:

The prospect of introducing a potent novel therapy that specifically targets a pivotal mediator of disease offers new hope to patients with rheumatoid arthritis (RA). There is convincing evidence that interleukin-1 (IL-1) plays a critical role in the pathogenesis of RA. In RA, the inadequate production of IL-1 receptor antagonist (IL-1Ra), the natural inhibitor of IL-1, results in increased IL-1-mediated pathophysiological activity. Unregulated IL-1-mediated effects produce enhanced tissue inflammation and progressive degradation of cartilage and bone matrix. Recombinant IL-1Ra treatment in experimental models of arthritis results in profound suppression of synovial inflammation and joint damage. Recombinant human IL-1Ra (rhu-IL-1Ra) has been evaluated in RA in several randomised clinical trials and was shown to significantly reduce both the clinical manifestations of arthritis and the rate of progressive joint damage. Firstly, in a 6-month placebo-controlled study, 43% of the patients who received the highest dose of rhu-IL-1Ra (150 mg/day) demonstrated a 20% improvement (American College of Rheumatology clinical criteria) compared to 27% of the patients who received placebo. In addition, the patients who received rhu-IL-1Ra demonstrated 46% less joint damage (Larsen scores). Secondly, in a 6-month extension of the placebo-controlled study, the treated patients maintained their clinical improvement and there was further significant reduction in the rate of progressive joint damage. The patients who had originally received placebo demonstrated both clinical and radiological responses that were similar to those observed in the treated patients during the initial phase of the study. Finally, in a combination study with methotrexate (MTX), 42% of patients who received MTX and the optimal dose of rhu-IL-1Ra (1.0 mg/kg/day) demonstrated an ACR 20% clinical response, compared to 23% of those receiving MTX and placebo. rhu-IL-1Ra was well tolerated in all studies and adverse events were uncommon. The most frequently reported adverse event causing withdrawal of treatment was an injection site reaction, occurring in approximately 5% of patients. In conclusion, targeted IL-1 inhibition significantly reduced both the clinical manifestations and the rate of progressive joint damage in patients with RA. These observations suggest that rhu-IL-1Ra has a potential role as a novel therapeutic modality in the future management of RA.

ISSN:1173-8804    

出版商:ADIS    

年代:2001

数据来源: ADIS

摘要:

Schönlein-Henoch syndrome is a form of systemic small-vessel vasculitis, characterised by vascular and/or mesangial immunoglobulin A1 deposits. The main clinical manifestations are vascular purpura, predominating on the lower limbs, and articular, gastrointestinal and renal symptoms. Pulmonary, cardiac, genital and neurological symptoms have also be observed. The syndrome usually affects children, whereas it is rare in adults.The frequency of renal involvement varies between individual studies (from 20 to 100%). Renal manifestations are usually mild and transient, although chronic nephropathies may occur. Overall, an estimated 2% of children with Schönlein-Henoch purpura progress to renal failure and up to 20% of children with nephritis treated in specialised centres require haemodialysis. The renal prognosis appears to be worse in adults. Aetiological investigations are required, as a triggering factor is found in approximately half the patients (e.g. viral, bacterial and parasitic infections, drugs, toxins, systemic diseases and cancer).Dapsone has beneficial effects on cutaneous, gastrointestinal and articular manifestations in adults, especially those with chronic forms. Corticosteroids may be useful for refractory abdominal pain. Methylprednisolone pulse therapy, immunosuppressive drugs (e.g. cyclophosphamide and azathioprine), plasma exchange and polyclonal immunoglobulin therapy are beneficial in very rare life-threatening forms of the disease and in rare instances where renal function is compromised.

ISSN:1173-8804    

出版商:ADIS    

年代:2001

数据来源: ADIS