Regulatory T cells and their role in rheumatic diseases: a potential target for novel therapeutic development

Clinical Features of COVID-19 Vaccine-Associated Autoimmune Hepatitis: A Systematic Review

Autoimmune hepatitis (AIH) is an inflammatory liver disease wherein the body's immune system instigates an attack on the liver, causing inflammation and hepatic impairment. This disease usually manifests in genetically predisposed individuals and is triggered by stimuli or environments such as viral infections, environmental toxins, and drugs. The causal role of COVID-19 vaccination in AIH remains uncertain. This review of 39 cases of vaccine-related AIH indicates that female patients above the age of 50 years or those with potential AIH risk factors may be susceptible to vaccine-related AIH, and the clinical features of vaccine-associated AIH are similar to those of idiopathic AIH. These features commonly manifest in patients after the first dose of vaccination, with symptom onset typically delayed by 10-14 days. The incidence of underlying liver disease in patients with potential health conditions associated to liver disease is similar to that of patients without preexisting illnesses. Steroid administration is effective in treating vaccine-related AIH-susceptible patients, with most patients experiencing improvement in their clinical symptoms. However, care should be taken to prevent bacterial infections during drug administration. Furthermore, the possible pathogenic mechanisms of vaccine-associated AIH are discussed to offer potential ideas for vaccine development and enhancement. Although the incidence of vaccine-related AIH is rare, individuals should not be deterred from receiving the COVID-19 vaccine, as the benefits of vaccination significantly outweigh the risks.

Using cyclophosphamide in inflammatory rheumatic diseases

Cyclophosphamide (CYC), primarily introduced into clinical practice as an anti-cancer substance, is a potent immunosuppressive drug. Today, it is used in a number of organ- or life -threatening autoimmune diseases such as systemic vasculitides or connective tissue diseases. While being effective, CYC has a small therapeutic index and is associated with significant toxicity. CYC has been used in oncology in a variety of diseases and a lot of data has been derived from this area. This knowledge is often extrapolated to the rheumatologic settings. However, besides some similarities substantial differences between these two specialties considering the underlying diseases as well as the kind of application of the drug exist. The aim of the present review is to describe the general characteristics of the use of CYC from the rheumatologist's point of view, including pharmacologic and pharmacokinetic properties, drug interactions, toxicity and possible preventive and/or therapeutic measures; all of which are important to consider when using this particular drug in the treatment of inflammatory rheumatic diseases.

Multiple pregnancy failures: an immunological paradigm

Recurrent spontaneous abortion (RSA), three or more pregnancy losses prior to 20 weeks, occurs in about 1% of all pregnancies, 50% of RSA cases remain unexplained and unresolved. Recently, immune pathways have been implicated in the pathophysiology of RSA. Immune tolerance of the fetal-placental unit and placental angiogenesis are mandatory for a successful pregnancy outcome. Unscheduled dysregulation of the placental vasculature is thought to be the pathophysiologic mechanisms underlying an array of pregnancy complications like infertility, miscarriage, pre-eclampsia, and fetal growth restriction and death. Investigations on mechanisms and management of RSA are mired by substandard design and lack of optimal randomized clinical trials and have resulted in disagreement on guidelines for evaluation and treatments for patients with multiple pregnancy losses of unknown etiology. The present review focuses on evidence-based research discussion with immunologic causes, and immune-regulatory therapies recommended for helping patients with a history of RSA. We highlight data that might support revalidation of low molecular weight heparin as a protective therapy in RSA. Newly launched growth factors, GM-CSF, and potentially novel agents to suppress inflammatory rejection, including regulatory T cells, human chorionic gonadotropin, and M-CSF/IL-10, may work in concert with tender-loving-care therapy and give hope to couples with multiple pregnancy losses.

IL-35-mediated induction of a potent regulatory T cell population

Regulatory T cells (T(reg) cells) have a critical role in the maintenance of immunological self-tolerance. Here we show that treatment of naive human or mouse T cells with IL-35 induced a regulatory population, which we call 'iT(R)35 cells', that mediated suppression via IL-35 but not via the inhibitory cytokines IL-10 or transforming growth factor-β (TGF-β). We found that iT(R)35 cells did not express or require the transcription factor Foxp3, and were strongly suppressive and stable in vivo. T(reg) cells induced the generation of iT(R)35 cells in an IL-35- and IL-10-dependent manner in vitro and induced their generation in vivo under inflammatory conditions in intestines infected with Trichuris muris and within the tumor microenvironment (B16 melanoma and MC38 colorectal adenocarcinoma), where they contributed to the regulatory milieu. Thus, iT(R)35 cells constitute a key mediator of infectious tolerance and contribute to T(reg) cell-mediated tumor progression. Furthermore, iT(R)35 cells generated ex vivo might have therapeutic utility.

Frequency of CD4+CD25high regulatory T cells in the peripheral blood of Egyptian children with autism

Autoimmunity may have a role in autism, although the origins of autoimmunity in autism are unknown. CD4( +)CD25(high) regulatory T cells play an important role in the establishment of immunological self-tolerance, thereby preventing autoimmunity. The authors are the first to study the frequency of CD4(+)CD25( high) regulatory T cells in the blood of 30 autistic and 30 age- and sex-matched healthy children. Patients with autism had significantly lower frequency of CD4(+)CD25(high) regulatory T cells than healthy children (P < .001). These cells were deficient in 73.3% of children with autism. Autistic patients with allergic manifestations (40%) and those with a family history of autoimmunity (53.3%) had a significantly lower frequency of CD4(+)CD25(high) regulatory T cells than those without (P < .01 and P < .001, respectively). In conclusion, CD4(+)CD25( high) regulatory T cells are deficient in many children with autism. Deficiency of these cells may contribute to autoimmunity in a subgroup of children with autism. Consequently, CD4(+)CD25(high) regulatory T cells could be new potential therapeutic targets in these patients.

Distribution of circulating cells in systemic juvenile idiopathic arthritis across disease activity states

Juvenile idiopathic arthritis (JIA) encompasses a group of chronic childhood arthritides of unknown etiology. One subtype, systemic JIA (SJIA), is characterized by a combination of arthritis and systemic inflammation. Its systemic nature suggests that clues to SJIA pathogenesis may be found in examination of peripheral blood cells. To determine the immunophenotypic profiles of circulating mononuclear cells in SJIA patients with different degrees of disease activity, we studied PBMC from 31 SJIA patients, 20 polyarticular JIA patients (similar to adult rheumatoid arthritis), and 31 age-matched controls. During SJIA disease flare, blood monocyte numbers were increased, whereas levels of myeloid dendritic cells (DC) and gammadelta T cells were reduced. At both flare and quiescence, increased levels of CD14 and CD16 were found on SJIA monocytes. Levels of CD16-DC were elevated at SJIA quiescence compared both to healthy controls and to SJIA subjects with active disease. Overall, our findings suggest dysregulation of innate immunity in SJIA and raise the possibility that quiescence represents a state of compensated inflammation.

Oligoarticular and polyarticular JIA: epidemiology and pathogenesis

Juvenile idiopathic arthritis (JIA) refers to a group of chronic childhood arthropathies of unknown etiology, currently classified into subtypes primarily on the basis of clinical features. Research has focused on the hypothesis that these subtypes arise through distinct etiologic pathways. In this Review, we discuss four subtypes of JIA: persistent oligoarticular, extended oligoarticular, rheumatoid-factor-positive polyarticular and rheumatoid-factor-negative polyarticular. These subtypes differ in prevalence between ethnic groups and are associated with different HLA alleles. Non-HLA genetic risk factors have also been identified, some of which reveal further molecular differences between these subtypes, while others suggest mechanistic overlap. Investigations of immunophenotypes also provide insights into subtype differences: adaptive immunity seems to have a prominent role in both polyarticular and oligoarticular JIA, and the more-limited arthritis observed in persistent oligoarticular JIA as compared with extended oligoarticular JIA may reflect more-potent immunoregulatory T-cell activity in the former. Tumor necrosis factor seems to be a key mediator of both polyarticular and oligoarticular JIA, especially in the extended oligoarticular subtype, although elevated levels of other cytokines are also observed. Limited data on monocytes, dendritic cells, B cells, natural killer T cells and neutrophils suggest that the contributions of these cells differ across subtypes of JIA. Within each subtype, however, common pathways seem to drive joint damage.