Primary biliary cirrhosis is an autoimmune cholestatic liver disease characterized by humoral and cellular response directed at mitochondrial autoantigens, mainly the E2 component of the pyruvate dehydrogenase complex. The etiology of PBC[1], like most polygenic autoimmune diseases, belongs to the "complex" category, including genetic elements and environmental factors. Many environmental factors, such as xenobiotics, smoking, hormonal therapy, toxins, oxidative stress and recurrent urinary tract infections, are associated with PBC. Infectious agents can trigger autoimmunity via several mechanisms and are associated with various autoimmune diseases. A relationship between PBC and several infectious agents, and a possible role for Escherichia coli in the pathogenesis of PBC has been suggested. The identification of a culprit agent that induces or exacerbates PBC might have diagnostic and therapeutic implications. This review evaluates the evidence for an infectious agent role in the pathogenesis of PBC.

Idiotypic analyses of anti-DNA autoantibodies were widely reported a decade ago. More than 100 studies were conducted on one of the main analyzed idiotypes, the 16/6 Id of the anti-ssDNA monoclonal antibody. In this review we summarize current knowledge on the characteristics of the 16/6 Id[1], its link to infection and its target epitopes on other molecules known so far. This includes the modulation of T and B cell responses and gene expression by the 16/6 mAb[2] in vitro and in vivo. We focus on the ability and mechanisms by which this idiotype induces experimental lupus in naïve mice, manifested by autoantibody spread, kidney and brain involvement, and leukopenia associated with enhanced sedimentation rate. We also discuss various therapeutic modalities to treat 16/6 induced lupus in mice.

The antiphospholipid syndrome is characterized by recurrent fetal loss, venous and/or arterial thrombosis, and thrombocytopenia associated with elevated titers of lupus anticoagulant and anticardiolipin antibodies. Although thrombosis is the characteristic vascular involvement in APS[1], the development of vascular aneurysms in patients with APS has been reported. We describe four patients with established APS, who developed abdominal aortic aneurysm, and review the literature on previous published cases of arterial aneurysms developing in patients with APS. In addition, we discuss the possible pathophysiological association between APS and the development of this vascular abnormality.

Background: Systemic lupus erythematosus is an autoimmune disease with diverse clinical manifestations that cannot always be regulated by steroids and immunosuppressive therapy. Intravenous immunoglobulin is an optional immunomodulatory agent for the treatment of SLE[1], but the appropriate indications for its use, duration of therapy and recommended dosage are yet to be established. In SLE patients, most publications report the utilization of a high dose (2 g/kg body weight) protocol.

Objectives: To investigate whether lower doses of IVIg are beneficial for SLE patients.

Methods: We retrospectively analyzed the medical records of 62 patients who received low dose IVIg[2] (approximately 0.5 g/kg body weight).

Results: The treatment was associated with clinical improvement in many specific disease manifestations, along with a continuous decrease in SLEDAI scores (SLE Disease Activity Index). However, thrombocytopenia, alopecia and vasculitis did not improve following IVIg therapy.

Conclusions: Low dose IVIg is a possible therapeutic option in SLE and is associated with lower cost than the high dose regimen and possibly fewer adverse effects.

Background: Infectious agents are important in the pathogenesis of autoimmune disease since they are a major part of the environmental trigger of autoimmunity. A negative relationship between latitude and infectious disease species richness has been suggested.

Objectives: To examine whether their prevalence differs in two latitudinally different populations.

Methods: The prevalence of infections with Toxoplasma gondii, rubella virus, cytomegalovirus, Epstein-Barr virus and Treponema pallidum was compared between subjects from Italy and Colombia.

Results: We found high titers of antibodies against four of five microorganisms tested, Toxoplasma gondii (50.8%), rubella virus (German measles) (75%), cytomegalovirus (86.3%), Epstein-Barr virus (83.3%) and Treponema pallidum (6.3%) in completely healthy individuals from a tropical country (Colombia) and a European country (Italy). Differences between two groups of volunteers were noted regarding two infectious agents. The prevalence of immunoglobulin G anti-rubella antibodies was significantly higher among Italian subjects (85% vs. 67.9%, P = 0.002), whereas antibodies against CMV[1] were less prevalent among Italian as compared to Colombian subjects (77% vs. 92.9%, P < 0.001).

Conclusions: These differences might also result in a different tendency towards development of autoimmune diseases associated with these infectious agents in different populations.

Chronic fatigue syndrome is a heterogeneous disorder with unknown pathogenesis and etiology, characterized by disabling fatigue, difficulty in concentration and memory, and concomitant skeletal and muscular pain. Several mechanisms have been suggested to play a role in CFS[1], such as excessive oxidative stress following exertion, immune imbalance characterized by decreased natural killer cell and macrophage activity, immunoglobulin G subclass deficiencies (IgG-1[2], IgG-3) and decreased serum concentrations of complement component. Autoantibodies were also suggested as a possible factor in the pathogenesis of CFS. Recent studies indicate that anti-serotonin, anti-microtubule-associated protein 2 and anti-muscarinic cholinergic receptor 1 may play a role in the pathogenesis of CFS. It has been demonstrated that impairment in vasoactive neuropeptide metabolism may explain the CFS symptoms