Properties of mutated murine alpha4beta2 nicotinic receptors linked to partial epilepsy

We characterized, by electrophysiological methods, two biophysical properties of murine recombinant alpha4beta2 nicotinic acetylcholine receptors (nAChR) bearing a mutation (alpha4:+L264alpha4:beta2 or alpha4:S252Falpha4:beta2) linked to autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE). Sensitivity to acetylcholine (ACh) was increased by the S252F substitution expressed in heterozygosis (alpha4:S252Falpha4:beta2) but was markedly reduced when this mutation was expressed in homozygosis (S252Falpha4:beta2). ACh sensitivity was not altered by the +L264 insertion. Moreover, receptor desensitization was significantly increased by both mutations expressed in heterozygosis. These results are in general agreement to those of rat and human recombinant receptors bearing the same mutations, thus contributing to validate the use of knock-in mice harboring ADNFLE mutations as models to study this pathology.     

A single-centre retrospective case series of Anakinra for incident calcium pyrophosphate deposition disease

Clinical Rheumatology - In this 2-year retrospective case series, we characterise the calcium pyrophosphate deposition disease (CPPD) inpatient cohort at a single centre and assess the efficacy and...     

In vitro cytokine production and proliferation of T cells from patients with anti‐proteinase 3‐ and antimyeloperoxidase‐associated vasculitis,in response to proteinase 3 and myeloperoxidase

Objective

To investigate in vitro proliferative responses of CD4+ T cells and generation of specific cytokines induced by stimulation of peripheral blood mononuclear cells (PBMCs) from patients with antineutrophil cytoplasmic antibody (ANCA)‐associated vasculitis with the autoantigens proteinase 3 (PR3) and myeloperoxidase (MPO).

Methods

PBMCs from vasculitis patients with PR3 ANCA or MPO ANCA and from healthy controls were stimulated for 7 days with PR3, MPO, or control stimuli. Proliferation of CD4+ T cells was assessed by flow cytometry, using the proliferation marker Ki‐67. Levels of the pro‐proliferative cytokines interleukin‐2 (IL‐2) and IL‐6 and of the Th1 and Th2 cytokines interferon‐γ (IFNγ) and IL‐10 in culture supernatants were determined.

Results

PR3 and MPO induced proliferative responses in CD4+ T cells from individual patients with ANCA‐associated vasculitides and healthy controls in vitro. Neither PR3 nor MPO elicited significant IL‐2 production. Levels of IL‐6 were highest after stimulation with PR3 but low after stimulation with MPO, independent of study group. Stimulation with PR3, and to a lesser extent with MPO, induced a Th2 cytokine milieu, characterized by high production of IL‐6 and IL‐10 and low production of IFNγ in patients and controls.

Conclusion

PR3 and MPO promote proliferation of CD4+ T cells from patients with ANCA‐associated vasculitides, but also cross‐stimulate T cells from healthy individuals. Strong IL‐10 production elicited by PR3 in vitro may act as an inhibitory signal for T cell proliferation and may have an important immunoregulatory function in vivo.