Egr2 and Egr3 in regulatory T cells cooperatively control systemic autoimmunity through Ltbp3-mediated TGF-ß3 production.

Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease characterized by multiorgan inflammation induced by autoantibodies. Early growth response gene 2 (Egr2), a transcription factor essential for T-cell anergy induction, controls systemic autoimmunity in mice and humans. We have previously identified a subpopulation of CD4+ regulatory T cells, CD4+CD25-LAG3+ cells, that characteristically express both Egr2 and LAG3 and control mice model of lupus via TGF-ß3 production. However, due to the mild phenotype of lymphocyte-specific Egr2-deficient mice, the presence of an additional regulator has been speculated. Here, we show that Egr2 and Egr3 expressed in T cells cooperatively prevent humoral immune responses by supporting TGF-ß3 secretion. T cell-specific Egr2/Egr3 double-deficient (Egr2/3DKO) mice spontaneously developed an early onset lupus-like disease that was more severe than in T cell-specific Egr2-deficient mice. In accordance with the observation that CD4+CD25-LAG3+ cells from Egr2/3DKO mice completely lost the capacity to produce TGF-ß3, the excessive germinal center reaction in Egr2/3DKO mice was suppressed by the adoptive transfer of WT CD4+CD25-LAG3+ cells or treatment with a TGF-ß3-expressing vector. Intriguingly, latent TGF-ß binding protein (Ltbp)3 expression maintained by Egr2 and Egr3 was required for TGF-ß3 production from CD4+CD25-LAG3+ cells. Because Egr2 and Egr3 did not demonstrate cell intrinsic suppression of the development of follicular helper T cells, Egr2- and Egr3-dependent TGF-ß3 production by CD4+CD25-LAG3+ cells is critical for controlling excessive B-cell responses. The unique attributes of Egr2/Egr3 in T cells may provide an opportunity for developing novel therapeutics for autoantibody-mediated diseases including SLE.

Perspectives on countermeasures against COVID-19 in the remote islands of Yaeyama region, Okinawa, Japan.

Numerous difficulties unique to remote island regions exist in the fight against coronavirus disease 2019 (COVID-19). For example, in the Yaeyama Medical Region (Okinawa, Japan), there are only clinics without beds on constituent islands. As medical resources are limited on remote islands, a single outbreak can put the entire medical system at risk. In addition, local governments need to maintain economic support while taking measures to contain outbreaks. For future COVID-19 countermeasures, it is essential to establish a response team in the regional hospital to conduct on-site epidemiological surveys as early as possible in a pandemic. In addition, distributing effective oral antivirals to remote islands may reduce the spread of infection and the number of severe cases requiring off-region transfer.

Rhabdomyolysis Induced by Isoniazid in a Patient with Rheumatoid Arthritis and End-stage Renal Disease: A Case Report and Review of the Literature.

A 76-year-old man complicated with end-stage renal disease had latent tuberculosis infection (LTBI), and isoniazid (INH) 300 mg daily was started to prevent reactivation of LTBI before using biologic agents for rheumatoid arthritis. On the 8th day after administration of INH, he presented with a fever, petechiae, and myalgia. Serological studies revealed elevated myogenic enzymes and creatinine level. Based on the exclusion of other etiologies, rapid improvement with cessation of INH, and the recurrence of the fever and myalgia with re-administration of a reduced dose of INH, we diagnosed him with INH-induced rhabdomyolysis. Physicians should be aware of rhabdomyolysis induced by INH at a therapeutic dose as an infrequent but potentially fatal adverse drug reaction.

Egr2-independent, Klf1-mediated induction of PD-L1 in CD4+ T cells.

Programmed death ligand 1 (PD-L1)-mediated induction of immune tolerance has been vigorously investigated in autoimmunity and anti-tumor immunity. However, details of the mechanism by which PD-L1 is induced in CD4+ T cells are unknown. Here, we revealed the potential function of Klf1 and Egr2-mediated induction of PD-L1 in CD4+ T cells. We focused on the molecules specifically expressed in CD4+CD25-LAG3+ regulatory T cells (LAG3+ Tregs) highly express of PD-L1 and transcription factor Egr2. Although ectopic expression of Egr2 induced PD-L1, a deficiency of Egr2 did not affect its expression, indicating the involvement of another PD-L1 induction mechanism. Comprehensive gene expression analysis of LAG3+ Tregs and in silico binding predictions revealed that Krüppel-like factor 1 (Klf1) is a candidate inducer of the PD-L1 gene (Cd274). Klf1 is a transcription factor that promotes ß-globin synthesis in erythroid progenitors, and its role in immunological homeostasis is unknown. Ectopic expression of Klf1 induced PD-L1 in CD4+ T cells through activation of the PI3K-mTOR signaling pathway, independent of STATs signaling and Egr2 expression. Our findings indicate that Klf1 and Egr2 are modulators of PD-L1-mediated immune suppression in CD4+ T cells and might provide new insights into therapeutic targets for autoimmune diseases and malignancies.

Pneumatosis Cystoides Intestinalis in Patients with Systemic Sclerosis: A Case Report and Review of 39 Japanese Cases.

Pneumatosis cystoides intestinalis (PCI) is a rare gastrointestinal complication of systemic sclerosis (SSc) characterized by intramural accumulation of gas within thin-walled cysts. We report the case of an 82-year-old female patient with pneumoperitoneum due to PCI associated with SSc and review the features of the 39 Japanese cases. The median patient age was 57 years (range 24-83 years) and the male/female ratio was 1 : 12. In the recent decade, 14 out of 15 cases (93.3%) evaluated with CT scans were diagnosed with PCI. The results suggest that CT scan may be a useful diagnostic tool for detecting PCI. PCI in patients with SSc is usually benign and requires only conservative therapy. However, two patients (5.1%) with signs of peritoneal irritation required surgery. When peritoneal irritation secondary to additional pathology is observed, surgical treatment may be warranted; a precise diagnosis for this condition is therefore essential.