Clec12a tempers inflammation while restricting expansion of a colitogenic commensal.

Regulation of the microbiota is critical to intestinal health yet the mechanisms employed by innate immunity remain unclear. Here we show that mice deficient in the C-Type-lectin receptor, Clec12a developed severe colitis, which was dependent on the microbiota. Fecal-microbiota-transplantation (FMT) studies into germfree mice revealed a colitogenic microbiota formed within Clec12a mice that was marked by expansion of the gram-positive organism, .

CD11c+ myeloid cell exosomes reduce intestinal inflammation during colitis.

Intercellular communication is critical for homeostasis in mammalian systems, including the gastrointestinal (GI) tract. Exosomes are nanoscale lipid extracellular vesicles that mediate communication between many cell types. Notably, the roles of immune cell exosomes in regulating GI homeostasis and inflammation are largely uncharacterized.

Epithelial-myeloid exchange of MHC class II constrains immunity and microbiota composition.

Intestinal epithelial cells (IECs) have long been understood to express high levels of major histocompatibility complex class II (MHC class II) molecules but are not considered canonical antigen-presenting cells, and the impact of IEC-MHC class II signaling on gut homeostasis remains enigmatic. As IECs serve as the primary barrier between underlying host immune cells, we reasoned that IEC-intrinsic antigen presentation may play a role in responses toward the microbiota. Mice with an IEC-intrinsic deletion of MHC class II (IEC) are healthy but have fewer microbial-bound IgA, regulatory T cells (Tregs), and immune repertoire selection.

Fiber Puts Lactobacillus to SLEep.

Few studies have analyzed how diet-induced changes in the microbiota influence lupus. In this issue of Cell Host & Microbe, Zegarra-Ruiz et al. (2019) find that translocation of Lactobacillus reuteri from the gut to systemic organs worsens lupus.

A member of the gut mycobiota modulates host purine metabolism exacerbating colitis in mice.

The commensal microbiota has an important impact on host health, which is only beginning to be elucidated. Despite the presence of fungal, archaeal, and viral members, most studies have focused solely on the bacterial microbiota. Antibodies against the yeast are found in some patients with Crohn's disease (CD), suggesting that the mycobiota may contribute to disease severity.

Evaluation of a high avidity anti-dsDNA IgG enzyme-linked immunosorbent assay for the diagnosis of systemic lupus erythematosus.

The high avidity (HA) anti-dsDNA IgG ELISA is considered highly specific for the diagnosis of systemic lupus erythematosus (SLE). The main objective of this study was to determine the performance of this test with existing assays for detecting anti-dsDNA IgG antibodies as well as assess its analytical characteristics. For method comparison studies, we investigated the correlation between the HA ELISA with 8 other assays for the detection of dsDNA IgG antibodies namely; six anti-dsDNA IgG ELISA, the Crithidia luciliae immunofluorescence test (CLIFT) and an in-house developed Farr radioimmunoassay (RIA).

Significant differences in the analytic concordance between anti-dsDNA IgG antibody assays for the diagnosis of systemic lupus erythematosus--implications for inter-laboratory testing.

Background: Anti-double stranded DNA (anti-dsDNA) autoantibodies are considered hallmark of systemic lupus erythematosus (SLE).

Methods: To determine concordance between assays for the detection of this marker, we analyzed 100 antinuclear antibody (ANA) positive sera with a homogeneous pattern and titers≥1:160 by indirect immunofluorescence assay (IFA) on HEp-2 cells, 100 consecutive anti-dsDNA IgG ELISA-negative as well as 100 healthy control samples using six commercial ELISAs and the Crithidia luciliae immunofluorescence test (CLIFT).

Results: The positivity rates for the ELISAs in the ANA positive group ranged from 55.