Background Pseudoxanthoma elasticum (PXE) is a genetic disease caused by mutations in the ABCC6 gene that result in low pyrophosphate levels and subsequent progressive soft tissue calcifications. PXE mainly affects the skin, retina, and arteries. However, many patients with PXE experience kidney stones. We determined the prevalence of this pathology in patients with PXE and examined the possible underlying mechanisms in murine models. Methods We conducted a retrospective study in a large cohort of patients with PXE and analyzed urine samples and kidneys from Abcc6 2/2 mice at various ages. We used Yasue staining, scanning electron microscopy, electron microscopy coupled to electron energy loss spectroscopy, and Fourier transform infrared microspectroscopy to characterize kidney calcifications. Results Among 113 patients with PXE, 45 (40%) had a past medical history of kidney stones. Five of six computed tomography scans performed showed evidence of massive papillary calcifications (Randall plaques). Abcc6 2/2 mice spontaneously developed kidney interstitial apatite calcifications with aging. These calcifications appeared specifically at the tip of the papilla and formed Randall plaques similar to those observed in human kidneys. Compared with controls, Abcc6 2/2 mice had low urinary excretion of pyrophosphate. Conclusions The frequency of kidney stones and probably, Randall plaque is extremely high in patients with PXE, and Abcc6 2/2 mice provide a new and useful model in which to study Randall plaque formation. Our findings also suggest that pyrophosphate administration should be evaluated for the prevention of Randall plaque and kidney stones.
ObjectiveThe worldwide COVID-19 vaccination campaign triggered several autoimmune diseases. We hereby aimed to describe IgA vasculitis (IgAV) following COVID- 19 vaccination.MethodsWe conducted a French national multi-centre, retrospective study of new onset adult IgAV diagnosis following COVID-19 vaccination.ResultsTwelve patients with a new onset IgAV were included. Five were women (41.6%), and the median age was 52,5 years IQR [30.75-60.5]. Ten received an mRNA vaccine. Two patients received a viral vector vaccine. The median time from vaccination to onset of symptoms was 11.5 days with an IQR of [4.25-21.25]. The vasculitis occurred after the first vaccine dose in most patients (n=8). All patients had skin involvement, with skin necrosis in four patients. Seven patients had joint involvement and 2 had arthritis. Four had non-severe gastrointestinal involvement. Two had non-severe renal involvement. Median C-reactive protein was 26 mg/l [10-66.75], median creatininaemia was 72 μmol/l [65-81], one patient had eGFR < 60 ml/min at management. All patients received a treatment, including glucocorticosteroids in 9 patients (75%). Five patients received a vaccine dose after developing IgAV, one of them experienced a minor cutaneous relapse.ConclusionBaseline presentation of IgAV following COVID-19 vaccination was mild to moderate and outcomes were favourable. Thus, a complete COVID-19 vaccination regimen should be completed in this population. Of note, a fortuitous link cannot be ruled out requiring a worldwide pharmacovigilance search now to confirm these findings.
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