A dual-acting DNASE1/DNASE1L3 biologic prevents autoimmunity and death in genetic and induced lupus models.

A defining feature of systemic lupus erythematosus (SLE) is loss of tolerance to self-DNA, and DNASE1L3 deficiency, the main enzyme responsible for chromatin degradation in blood, is also associated with SLE. This association includes an ultra-rare pediatric population with DNASE1L3 deficiency who develop SLE, adult patients with loss of function variants of DNASE1L3 who are at a higher risk for SLE, and patients with sporadic SLE who have neutralizing autoantibodies to DNASE1L3. To mitigate the pathogenic effects of inherited and acquired DNASE1L3 deficiencies, we engineered a long-acting enzyme biologic with dual DNASE1/DNASE1L3 activity that is resistant to DNASE1 and DNASE1L3 inhibitors. Notably, we found that the biologic prevented the development of lupus in Dnase1-/-/Dnase1L3-/- double knockout mice and rescued animals from death in pristane-induced lupus. Finally, we confirmed that the human isoform of the enzyme biologic was not recognized by autoantibodies in SLE and efficiently degrades genomic and mitochondrial cell free DNA, as well as microparticle DNA, in SLE plasma. Our findings suggest that autoimmune diseases characterized by aberrant DNA accumulation, such as SLE, can be effectively treated with a replacement DNASE tailored to bypass pathogenic mechanisms, both genetic and acquired, that restrict DNASE1L3 activity.

Diagnostic Dilemma in a Case of Necrotizing Lymphadenitis With Macrophage Activation Syndrome.

Necrotizing lymphadenitis is a histological diagnosis that can arise from various conditions, including lupus lymphadenitis (LL), Kikuchi disease (KD), and infectious causes. Distinguishing between Kikuchi disease and lupus lymphadenitis can be challenging in clinical practice. In this report, we present the clinical scenario of a young female patient with lymphadenopathy and elucidate the process through which we ultimately arrived at a diagnosis of systemic lupus erythematosus (SLE) with macrophage activation syndrome. This case underscores the significance of recognizing Kikuchi disease as a condition that can mimic lupus and sheds light on the distinguishing features of necrotizing lymphadenitis, with a particular focus on Kikuchi disease and lupus lymphadenitis.