Complement, infection, and autoimmunity.

Purpose Of Review: Complement system dysfunction in terms of upregulation, downregulation, or dysregulation can create an imbalance of both host defense and inflammatory response leading to autoimmunity. In this review, we aimed at describing the role of complement system in host defense to inflection and in autoimmunity starting from the evidence from primary and secondary complement system deficiencies.

Recent Findings: Complement system has a determinant role in defense against infections: deficiencies of complement components are associated with increased susceptibility to infections.

Remission and low disease activity in a cohort of real-life patients with rheumatoid arthritis treated with first-line antitumour necrosis factor.

Objectives: This retrospective study used various indices to evaluate remission and low disease activity in 'real life' patients with rheumatoid arthritis (RA), given antitumour necrosis factor (anti-TNF) as a first-line treatment; changes in concomitant steroid and conventional synthetic disease-modifying antirheumatic drug (csDMARD) treatment were also assessed.

Methods: Remission and low disease activity were analysed in patients with RA treated with anti-TNF using the 28-joint Disease Activity Score (DAS28), Simplified Disease Activity Index (SDAI) and Clinical Disease Activity Index (CDAI). Remission and low disease activity were recorded after 6 months, 1 year and 2 years, along with concomitant prednisone and csDMARD treatment.

Small-Medium Vessel Vasculitides: is the Complement System a Potential Forgotten Target?

Systemic vasculitides are a group of uncommon diseases characterized by blood vessel inflammation. The complement system is involved in the pathogenesis and clinical manifestations of several autoimmune diseases, including systemic vasculitides. This enzymatic system is a component of the innate immune system.

The autoimmune side of hereditary angioedema: insights on the pathogenesis.

Hereditary angioedema (HAE) is an autosomal dominant disease resulting from the deficiency of C1 inhibitor (C1-INH), a glycosylated serine protease inhibitor that plays a regulatory role in the complement system (CS), the contact system and the intrinsic coagulation cascade. HAE disease severity is highly variable and may be influenced by genetic polymorphisms as well as by other factors, such as gender hormone-mediated effects. In HAE, the potential inadequate clearance of immune-complexes (IC) in the presence of reduced levels of CS components and in turn an excess of IC in the tissues results in inflammatory damage and release of autoantigens that may trigger an autoimmune response.

Use of anti-tumor necrosis factor alpha therapy in patients with concurrent rheumatoid arthritis and hepatitis B or hepatitis C: a retrospective analysis of 32 patients.

The safety of tumor necrosis factor-alpha (TNF-α) inhibitors in the setting of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections is controversial. The use of anti-TNF-α in rheumatoid arthritis (RA) is associated with an increased risk of hepatitis re-activation. This paper reports experience of using etanercept and adalimumab in 32 patients with RA and previous HBV or HCV infection.

Vasculitides and the Complement System: a Comprehensive Review.

Systemic vasculitides are a group of rare diseases characterized by inflammation of the arterial or venous vessel wall, causing stenosis or thrombosis. Clinical symptoms may be limited to skin or to other organs or may include multiple manifestations as systemic conditions. The pathogenesis is related to the presence of leukocytes in the vessels and to the IC deposition, which implies the activation of the complement system (CS) and then the swelling and damage of vessel mural structures.

Biologic agents for rheumatoid arthritis: can we hypothesize new strategies of treatment?

Rheumatoid arthritis is a complex multifactorial disease, whose pathogenesis has not been fully elucidated. Biologic agents have revolutionized RA treatment, but a significant percentage of patients does not obtain an adequate response to the therapy. Most of the biologic agents do better if combined with conventional immunosuppressive DMARDs and they show a similar efficacy profile: most of the responders achieve the minimum desirable level of response (ACR20) and only few patients obtain a worthwhile clinical improvement (ACR70 or better).

Complement and autoimmunity.

The complement system is a component of the innate immune system. Its main function was initially believed to be limited to the recognition and elimination of pathogens through direct killing or stimulation of phagocytosis. However, in recent years, the immunoregulatory functions of the complement system were demonstrated and it was determined that the complement proteins play an important role in modulating adaptive immunity and in bridging innate and adaptive responses.

Immunomodulation in psoriatic arthritis: focus on cellular and molecular pathways.

Psoriatic arthritis (PsA) is a chronic inflammatory arthropathy associated with psoriasis. Pathogenesis is incompletely understood and pathophysiological role of synovium is just beginning to be elucidated. PsA could be considered an enthesal disease and this hypothesis is the link between mechanical stress (entheses) and immunologically active tissue (synovium).

Role of the complement system in rheumatoid arthritis and psoriatic arthritis: relationship with anti-TNF inhibitors.

The complement system is an essential component of innate immunity and also plays an important role in modulating adaptive immunity. It comprises more than 30 plasma and membrane-bound proteins and can be activated through three pathways: the classical, the alternative and the lectin pathways. Its activation contributes to the pathogenesis of several autoimmune and inflammatory conditions.