Investigating phagocytic markers in Juvenile-onset Systemic Lupus Erythematosus (JSLE) monocytes and macrophages



Harris, David
Investigating phagocytic markers in Juvenile-onset Systemic Lupus Erythematosus (JSLE) monocytes and macrophages. [Unspecified]

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Abstract

Background Juvenile-onset systemic lupus erythematosus (JSLE) is a chronic, severe, multi-systemic autoimmune disease. Impaired phagocytic function has been implicated as an initial step in the pathogenesis of this disease, in relation to the clearance of cells undergoing apoptosis. The apoptotic process has been shown to be dysregulated in neutrophils, and these cells, and others, are thought to represent a burden of autoantigen-presenting apoptotic cells. After a sequence of immune cell activation, the result is the production of autoantibodies forming immune complexes which cause deleterious effects at end-organs. As key phagocytes, the phenotypes of JSLE macrophages, and their precursors monocytes, have been investigated to determine the extent of their role in the development of JSLE. Aim To elucidate phenotype and phagocytic function of monocytes and macrophages as a potential important contributing factor to the development of JSLE. Methods Monocytes were separated from processed whole blood of JSLE patients and paediatric healthy controls (HC), and either retained or cultured to macrophages, with the RNA extracted. RNA was converted to cDNA and real-time qPCR performed with primers for CD36, MER, and CR3, with expression standardised against that of β2M. Concentrations of soluble MER (sMER) were measured in JSLE, JIA and HC plasma samples by ELISA. These samples were diluted to a concentration of 1 in 5, following validation and optimisation conducted through spike and recovery. Adult HC monocytes were incubated with pHrodo E. coli for 30 minutes in JSLE and control plasma and serum, and phagocytosis was measured by flow cytometry. Adult HC monocytes were exposed to a number of environments (LPS, IFNα, TNFα, apoptotic neutrophils) for 2 and 6 hours. Supernatant was extracted and tested by human total MER ELISA, and monocyte RNA was extracted and RT-qPCR performed. Results Increased mRNA levels of CD36 were present in JSLE monocytes (p=0.025) but no differences found with MER or CR3 expression compared with HC monocytes, no differences in expression of these markers in macrophages. CR3 was down-regulated in both JSLE monocytes and macrophages, but no other differences were statistically significant. The concentrations of sMER were significantly greater in JSLE patients compared with HC (p

Item Type: Unspecified
Additional Information: Date: 2012-08 (completed)
Subjects: R Medicine > R Medicine (General)
R Medicine > RJ Pediatrics > RJ101 Child Health. Child health services
Divisions: ?? sch_health ??
Depositing User: Symplectic Admin
Date Deposited: 11 Jan 2013 10:53
Last Modified: 17 Jan 2020 08:10
URI: http://livrepository.liverpool.ac.uk/id/eprint/8179