Implication of a lysosomal antigen in the pathogenesis of lupus erythematosus.

Naturally-occurring autoantibodies to certain components of autophagy processes have been described in a few autoimmune diseases, but their fine specificity, their relationships with clinical phenotypes, and their potential pathogenic functions remain elusive. Here, we explored IgG autoantibodies reacting with a panel of cytoplasmic endosomal/lysosomal antigens and individual heat-shock proteins, all of which share links to autophagy. Sera from autoimmune patients and from MRL/lpr and NZB/W lupus-prone mice reacted with the C-terminal residues of lysosome-associated membrane glycoprotein (LAMP)2A. No cross-reaction was observed with LAMP2B or LAMP2C variants, with dsDNA or mononucleosomes, or with heat-shock protein A8. Moreover, administering chromatography-purified LAMP2A autoantibodies to MRL/lpr mice accelerated mortality. Furthermore, flow cytometry revealed elevated cell-surface expression of LAMP2A on MRL/lpr B cells. These findings reveal the involvement of a new class of autoantibodies targeting the C-terminus of LAMP2A, a receptor for cytosolic proteins targeted for degradation via chaperone-mediated autophagy. These autoantibodies could affect the autophagy process, which is abnormally upregulated in lupus. The data presented support a novel connection between autophagy dysregulation, autoimmune processes and pathophysiology in lupus.

The Effectiveness of Topical Cerium Nitrate-Silver Sulfadiazine Application on Overall Outcome in Patients with Calciphylaxis.

BACKGROUND: Calciphylaxis (CPX) is a rare and life-threatening disease characterized by vascular calcification and development of painful and necrotizing skin lesions with a challenging management. Mechanisms of CPX are complex and include an imbalance between vascular calcification promoters and inhibitors, and frequently vitamin K deficiency. OBJECTIVES: To describe the various presentations and identify predictive factors of death in patients with CPX. METHODS: In this multicenter retrospective study, we included 71 CPX patients followed in South-West France (n = 26) and in French Polynesia (n = 45), and who all received sodium thiosulfate (25 g thrice weekly for a median of 61 days). RESULTS: Characteristics at presentation significantly differed between metropolitan and Polynesian French patients. Polynesians were less frequently on regular dialysis at the onset of CPX, had a higher incidence of diabetes mellitus and obesity, more disturbances of calcium-phosphorus metabolism, and received vitamin K antagonists less frequently than patients from South-West France. Despite intensive management, the 1-year mortality rate was 66% and median time to death was 200 days (IQR, 40; 514). The number of body areas involved (i.e., three: OR 2.70 [1.09; 6.65], p = 0.031; four: OR 8.79 [1.54; 50.29], p = 0.015) was the only predictive factor for death, whereas application of topical cerium nitrate-silver sulfadiazine was protective (OR 0.44 [0.20; 0.99], p = 0.046). Surgical debridement, hyperbaric oxygenation therapy, and geographical origin were not associated with overall outcomes. CONCLUSIONS: Cerium nitrate may lead to vascular decalcification and chelation of reactive oxygen species, and prevent infection. Cerium nitrate-silver sulfadiazine was associated with better outcomes and should be tested in a prospective comparative trial in CPX patients.

Incidence and outcome of lupus nephritis in French Polynesia
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OBJECTIVE: Outcomes of systemic lupus erythematosus (SLE) and lupus nephritis (LN) are highly heterogeneous among some populations because of interactions between genetic, epigenetic, environmental, and socioeconomic factors. A better characterization of social and ethnic disparities in mixed populations may thus help to develop individualized treatment regimens. MATERIALS AND METHODS: Retrospective observational study including all patients with LN diagnosed between January 1993 and January 2014 in the only Nephrology Department of French Polynesia. RESULTS: The annual incidence of SLE and LN in French Polynesia was 3.6 and 0.96 per 100,000, respectively. Among the 45 patients with biopsy-proven LN (pediatric onset, 26.7%), LN occurred during the first SLE flare-up in 68.8%. At presentation, median eGFR was 72 mL/min/1.73m2 (31 - 105), 32 patients had class-III/IV active glomerulonephritis (GN), and 10 had pure or mixed class-V GN. During the follow-up, 5 patients died (11.1%) and 2 reached end-stage renal disease (4.4%). Cumulative incidences of complete and partial renal responses were 31.1% and 40% at 12 months. Complete renal response (CR) was only predicted by renal presentation (lack of leukocyturia, low proteinuria). Among the 36 patients with renal response, 18 relapsed. Maintenance treatment (mycophenolate mofetil) and place of residence (Windward Islands as compared to remote islands) were the only factors that protected from relapse. CONCLUSION: Renal presentation was the main predictive factor for a renal response whereas geographical residence and maintenance-treatment regimen were predictive of LN relapses in patients from French Polynesia, an area characterized by a specific genetic background and including several isolated islands that have limited access to healthcare.
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[Infectious complications rate from hemodialysis catheters: experience from the French Polynesia]. / Évaluation des complications infectieuses liées aux cathéters veineux centraux d'hémodialyse en Polynésie française.

The arterio-venous fistula (AVF) is the most common vascular access to perform hemodialysis (HD). The HD venous central catheter use should only be proposed to old patients and/or patients without vascular access construction feasibility. These HD catheters are often responsible of infectious and thrombosis complications. We performed, for the first time in French Polynesia, a retrospective study based on 214 patients receiving 618 HD catheters, to evaluate the infectious complication rate due to HD catheters. We showed that 17.4% of HD catheters present with infection. The number of bacteraemia due to HD catheters is 2.57/1000 days-catheters and the number of infection due to HD catheter is 1.43/1000 days-catheters. Eighteen percent of patients requiring an emergency HD without AVF access are transferred in intensive care unit due to infectious HD catheter complications. We observed a similar bacteriological environment than in literature. However, the number of tunneled HD catheter is really lower to that of the number required in European recommendations and we observed an abnormal number of non-functional AVF 1 month after creation. These results involve our nephrology unit to increase the number of tunneled catheters to limit the infectious risk and also to fit with the best practices guidelines.

Chelonitoxism: new case reports in French Polynesia and review of the literature.

Eating the flesh of some marine turtles can cause a type of seafood poisoning called chelonitoxism. The purpose of this article is to report a new case of mass poisoning caused by consumption of sea turtle flesh in French Polynesia. The episode involved 19 members of the same family. Three persons required hospitalization after consuming two consecutive meals including turtle flesh. One 26-year-old woman who was pregnant at 14 weeks of amenorrhea lapsed into a coma and died due to multiorgan failure on the third day after the meal. This case confirms the potential severity of chelonitoxism as reported in several series in the literature showing high mortality rates. The causative toxins are currently unidentified. Further study is needed to better understand chelonitoxism.