Neutropenia and neutrophil dysfunction cause serious infections and inflammatory bowel disease in glycogen storage disease Ib (GSD-Ib). Our discovery that accumulating 1,5-anhydroglucitol-6-phosphate causes neutropenia in a G6PC3-deficient mouse model and in the two rare diseases (GSD-Ib and G6PC3-deficiency) led us to repurpose the widely used antidiabetic drug empagliflozin, an inhibitor of the renal glucose co-transporter SGLT2. Off-label use of empagliflozin in four GSD-Ib patients with incomplete response to granulocyte colony stimulating factor (GCSF) treatment decreased serum 1,5-anhydroglucitol and neutrophil 1,5-anhydroglucitol-6-phosphate levels within one month. Clinically, symptoms of frequent infections, mucosal lesions, and inflammatory bowel disease resolved, and no symptomatic hypoglycemia was observed. GCSF could be discontinued in two patients and tapered down - by 57 and 81%, respectively - in the other two. The fluctuating neutrophil numbers in all patients were increased and stabilized. We further show the improved neutrophil function: we show a normal oxidative burst (in three of three patients tested, 3/3), a corrected protein glycosylation (2/2), as well as a normal neutrophil chemotaxis (1/1), and bactericidal activity (1/1) under treatment. In conclusion, the glucose lowering drug empagliflozin, used for the frequent and acquired disease type 2 diabetes, was successfully repurposed for treating neutropenia and neutrophil dysfunction in the rare inherited metabolic disorder GSD-Ib without causing symptomatic hypoglycemia. We ascribe this to an improvement of the neutrophil function due to the reduction of the intracellular concentration of 1,5-anhydroglucitol-6-phosphate.

Many SARS CoV-2 serology tests have proven to be less accurate than expected and do not assess antibody function as neutralizing, correlating with protection from reinfection. A new assay technology measuring the interaction of purified SARS CoV-2 spike protein receptor binding domain (RBD) with the extracellular domain of the human ACE2 receptor detects these important antibodies. This cPassTM surrogate virus neutralization test (sVNT) when compared directly with eight SARS CoV-2 IgG serology and two live cell neutralization tests gives similar or improved accuracy for qualitative delineation between positive and negative individuals in a fast, scalable and high throughput assay. The combined data support cPassTM sVNT as a tool for highly accurate SARS CoV-2 immunity surveillance of infected/recovered and/or vaccinated individuals, as well as drug and convalescent donor screening. The data also prevue a novel application for cPassTM sVNT in calibrating the stringency of live cell neutralization tests and its use in longitudinal testing of recovered and/or vaccinated patients.

No abstract

Natural killer (NK) cells produce interferon (IFN)-γ and thus have been suggested to promote type I immunity during bacterial infections. Yet, Listeria monocytogenes (Lm) and some other pathogens encode proteins that cause increased NK cell activation. Here, we show that stimulation of NK cell activation increases susceptibility during Lm infection despite and independent from robust NK cell production of IFNγ. The increased susceptibility correlated with IL-10 production by responding NK cells. NK cells produced IL-10 as their IFNγ production waned and the Lm virulence protein p60 promoted induction of IL-10 production by mouse and human NK cells. NK cells consequently exerted regulatory effects to suppress accumulation and activation of inflammatory myeloid cells. Our results reveal new dimensions of the role played by NK cells during Lm infection and demonstrate the ability of this bacterial pathogen to exploit the induction of regulatory NK cell activity to increase host susceptibility.