Clinical characteristics of early-onset paediatric systemic lupus erythematosus in a single centre in China

Red flags to suspect inborn errors of immunity in patients with autoimmune diseases

Inborn errors of immunity are monogenic disorders that predispose patients to immune dysregulation, autoimmunity, and infection. Some autoimmune diseases, such as autoimmune cytopenias, systemic lupus erythematosus, and inflammatory bowel diseases, are increasingly recognized as phenotypes of inborn errors of immunity. The objective of this article was to identify red flags or clinical/laboratory markers to suspect inborn errors of immunity in patients with autoimmune cytopenias, systemic lupus erythematosus, and inflammatory bowel diseases through a systematic literature review. The study followed the systematic reviews and meta-analysis guidelines (PRISMA). After selection, we included 36 articles, and their methodological quality was verified using the Joanna Briggs Institute tools for individual risk of bias analysis. The principal red flags in autoimmune cytopenias are chronic, recurrent, and refractory cytopenias, recurrent infection, severe infectious complications associated with immunosuppressive treatment, and chronic lymphoproliferation. In systemic lupus erythematosus, red flags include age of onset before five years, severe organ involvement, chilblain lesions, and chronic lymphoproliferation. For inflammatory bowel diseases, red flags are an age of onset before two years, resistance to conventional therapies, atypical endoscopic or histologic findings, and consanguineous parents. Autoimmune diseases may be the primary manifestation of inborn errors of immunity in pediatric and adult patients. An early diagnosis of a monogenic disorder allows for the tailoring of effective treatment plans, providing prognostic information to families, and offering genetic counseling.

A single-centre study on abnormal antinuclear antibodies in children caused by intravenous infusion of gamma globulin

Objective

To clarify the impact of intravenous infusion of gamma globulin (IVIg) on antinuclear antibodies (ANAs) in children.

Methods

A retrospective analysis was performed on the data of children with nonspecific autoantibody-related diseases whose antinuclear antibody (ANA) and autoantibody profiles were detected in our hospital from January to March 2022. A total of 108 patients with a clear history of IVIg infusion within 28 days composed the IVIg group, and 1201 patients without a history of IVIg infusion composed the non-IVIg group.

Results

All patients in the IVIg group had either positive ANAs or positive autoantibodies. Anti-SSA, anti-Ro52 and anti-AMA Mi2 were the top three autoantibodies in the IVIg group. The proportions of patients who were positive for either of these three autoantibodies in the IVIg group were significantly greater than those in the non-IVIg group (all P<0.5). Spearman correlation analysis revealed that the signal intensities of anti-SSA and anti-Ro52 were negatively correlated with the number of days of ANA detection after IVIg infusion (P<0.05). Multiple logistic analyses revealed that a greater total dosage of IVIg, greater IVIg per kilogram of body weight, and fewer ANA detection days after IVIg infusion were independent risk factors for positive anti-SSA and anti-Ro52 results.

Conclusions

It is recommended that if rheumatic diseases are suspected, ANA detection should be carried out beforeIVIg infusion. But for patients who are positive for at least one of these three autoantibodies after IVIg infusion, doctors should first consider adoptive antibodies.

Human and Murine Toll-like Receptor-Driven Disease in Systemic Lupus Erythematosus

The pathogenesis of systemic lupus erythematosus (SLE) is linked to the differential roles of toll-like receptors (TLRs), particularly TLR7, TLR8, and TLR9. TLR7 overexpression or gene duplication, as seen with the Y-linked autoimmune accelerator (Yaa) locus or TLR7 agonist imiquimod, correlates with increased SLE severity, and specific TLR7 polymorphisms and gain-of-function variants are associated with enhanced SLE susceptibility and severity. In addition, the X-chromosome location of TLR7 and its escape from X-chromosome inactivation provide a genetic basis for female predominance in SLE. The absence of TLR8 and TLR9 have been shown to exacerbate the detrimental effects of TLR7, leading to upregulated TLR7 activity and increased disease severity in mouse models of SLE. The regulatory functions of TLR8 and TLR9 have been proposed to involve competition for the endosomal trafficking chaperone UNC93B1. However, recent evidence implies more direct, regulatory functions of TLR9 on TLR7 activity. The association between age-associated B cells (ABCs) and autoantibody production positions these cells as potential targets for treatment in SLE, but the lack of specific markers necessitates further research for precise therapeutic intervention. Therapeutically, targeting TLRs is a promising strategy for SLE treatment, with drugs like hydroxychloroquine already in clinical use.

Monogenic lupus: insights into disease pathogenesis and therapeutic opportunities

PURPOSE OF REVIEW

This review aims to provide an overview of the genes and molecular pathways involved in monogenic lupus, the implications for genome diagnosis, and the potential therapies targeting these molecular mechanisms.

RECENT FINDINGS

To date, more than 30 genes have been identified as contributors to monogenic lupus. These genes are primarily related to complement deficiency, activation of the type I interferon (IFN) pathway, disruption of B-cell and T-cell tolerance and metabolic pathways, which reveal the multifaceted nature of systemic lupus erythematosus (SLE) pathogenesis.

SUMMARY

In-depth study of the causes of monogenic lupus can provide valuable insights into of pathogenic mechanisms of SLE, facilitate the identification of effective biomarkers, and aid in developing therapeutic strategies.

Integrins in Health and Disease-Suitable Targets for Treatment?

Integrin receptors are heterodimeric surface receptors that play multiple roles regarding cell-cell communication, signaling, and migration. The four members of the β2 integrin subfamily are composed of an alternative α (CD11a-d) subunit, which determines the specific receptor properties, and a constant β (CD18) subunit. This review aims to present insight into the multiple immunological roles of integrin receptors, with a focus on β2 integrins that are specifically expressed by leukocytes. The pathophysiological role of β2 integrins is confirmed by the drastic phenotype of patients suffering from leukocyte adhesion deficiencies, most often resulting in severe recurrent infections and, at the same time, a predisposition for autoimmune diseases. So far, studies on the role of β2 integrins in vivo employed mice with a constitutive knockout of all β2 integrins or either family member, respectively, which complicated the differentiation between the direct and indirect effects of β2 integrin deficiency for distinct cell types. The recent generation and characterization of transgenic mice with a cell-type-specific knockdown of β2 integrins by our group has enabled the dissection of cell-specific roles of β2 integrins. Further, integrin receptors have been recognized as target receptors for the treatment of inflammatory diseases as well as tumor therapy. However, whereas both agonistic and antagonistic agents yielded beneficial effects in animal models, the success of clinical trials was limited in most cases and was associated with unwanted side effects. This unfavorable outcome is most probably related to the systemic effects of the used compounds on all leukocytes, thereby emphasizing the need to develop formulations that target distinct types of leukocytes to modulate β2 integrin activity for therapeutic applications.

An early-onset SLE patient with a novel paternal inherited BACH2 mutation

BACH2-related immunodeficiency and autoimmunity (BRIDA) is an inborn error of immunity, newly reported in 2017, presenting with symptoms of immunoglobulin deficiency and ongoing colitis. Studies using a mouse model have demonstrated that BACH2 deficiency predisposes individuals to systemic lupus erythematosus (SLE); however, no BACH2 deficiency has been reported in SLE patients. Here we describe a patient with BRIDA presenting with early-onset SLE, juvenile dermatomyositis, and IgA deficiency. Whole exome sequencing analysis of the patient and her parents revealed a novel heterozygous point mutation in BACH2, c.G1727T, resulting in substitution of a highly conserved arginine with leucine (R576L), which is predicted to be deleterious, in the patient and her father. Reduced BACH2 expression and deficient transcriptional repression of the BACH2 target, BLIMP1, were detected in PBMCs or lymphoblastoid cell lines of our patient. Notably, extreme reduction of memory B cells was detected in the patient's father, although he had no obvious symptoms. SLE symptoms and recurrent fever were relieved by treatment with prednisone combined with tofacitinib. Thus, we present the second report of BRIDA and demonstrate that BACH2 may be a monogenic cause of SLE.