title: The expression and clinical significance of different forms of Mer receptor tyrosine kinase in systemic lupus erythematosus.
abstract: OBJECTIVE
  To investigate the expression and clinical significance of trans-membrane MerTK (mMer) on circulating CD14+ monocytes/macrophages and soluble MerTK (sMer) levels in plasma in systemic lupus erythematosus (SLE).
  
  
  METHODS
  108 SLE patients and 42 healthy controls were recruited in this study. The expression of mMer on the surfaces of CD14+ monocytes/macrophages was evaluated by flow cytometry (FCM). The sMer levels were measured by ELISA. Real-time quantitative PCR was applied to evaluate the mRNA levels of MerTK and ADAM17.
  
  
  RESULTS
  Both mMer expression on CD14+ monocytes/macrophages and sMer levels in plasma significantly increased in SLE patients compared to healthy subjects. The frequency of anti-inflammatory MerTK expressing CD14+CD16+ monocytes decreased in SLE. mMer expression was positively correlated with CD163 expression on CD14+ cells. Both the mMer expression on CD14+ monocytes/macrophages and sMer levels in plasma were positively correlated with SLEDAI. Furthermore, more elevated mMer and sMer levels were found in patients with higher SLEDAI, presence of anti-SSA, anti-Sm autoantibodies, and lupus nephritis.
  
  
  CONCLUSIONS
  Both mMer and sMer levels significantly increased in SLE and positively correlated with disease activity and severity. The upregulation of MerTK expression may serve as a biomarker of the disease activity and severity of SLE.
authors.affiliation: Department of Rheumatology and Immunology, Peking University People's Hospital, 11 Xizhimen South Street, Beijing 100044, China.
authors.forename: Huaqun
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Department of Rheumatology and Immunology, Peking University People's Hospital, 11 Xizhimen South Street, Beijing 100044, China.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Sun
authors.affiliation: Department of Rheumatology and Immunology, Peking University People's Hospital, 11 Xizhimen South Street, Beijing 100044, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Department of Rheumatology and Immunology, Peking University People's Hospital, 11 Xizhimen South Street, Beijing 100044, China.
authors.forename: Fanlei
authors.initials: F
authors.lastname: Hu
authors.affiliation: Department of Rheumatology and Immunology, Peking University People's Hospital, 11 Xizhimen South Street, Beijing 100044, China.
authors.forename: Lianjie
authors.initials: L
authors.lastname: Shi
authors.affiliation: Department of Rheumatology and Immunology, Peking University People's Hospital, 11 Xizhimen South Street, Beijing 100044, China.
authors.forename: Zhanguo
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Rheumatology and Immunology, Peking University People's Hospital, 11 Xizhimen South Street, Beijing 100044, China.
authors.forename: Yin
authors.initials: Y
authors.lastname: Su
mesh_terms: D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism; D000072198:ADAM17 Protein; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D005260:Female; D015870:Gene Expression; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D020794:Receptor Protein-Tyrosine Kinases / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D012720:Severity of Illness Index; D055815:Young Adult; D000076202:c-Mer Tyrosine Kinase
chemical_list: D015415:Biomarkers; D018950:Lipopolysaccharide Receptors; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; C097072:MERTK protein, human; D020794:Receptor Protein-Tyrosine Kinases; D000076202:c-Mer Tyrosine Kinase; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human
references.citation: J Autoimmun. 2010 Dec;35(4):368-74
references.pmid: 20822883
references.citation: Arthritis Res Ther. 2013 Mar 12;15(2):R41
references.pmid: 23497733
references.citation: J Immunol. 2011 Oct 15;187(8):4178-86
references.pmid: 21918185
references.citation: Cell Growth Differ. 1994 Jun;5(6):647-57
references.pmid: 8086340
references.citation: J Immunol. 2012 Oct 1;189(7):3508-20
references.pmid: 22942426
references.citation: Cytokine Growth Factor Rev. 2006 Aug;17(4):295-304
references.pmid: 16737840
references.citation: J Immunol. 2009 Aug 1;183(3):2167-75
references.pmid: 19597001
references.citation: J Immunol. 2010 Nov 15;185(10):5859-68
references.pmid: 20952679
references.citation: Cardiovasc Res. 2013 Jan 1;97(1):125-33
references.pmid: 22997156
references.citation: Blood. 2007 Feb 1;109(3):1026-33
references.pmid: 17047157
references.citation: Rheumatol Int. 2002 Mar;21(5):189-92
references.pmid: 11958435
references.citation: J Immunol. 2013 May 15;190(10):5237-46
references.pmid: 23596310
references.citation: J Autoimmun. 2007 Mar-May;28(2-3):114-21
references.pmid: 17368845
references.citation: Science. 2001 Jul 13;293(5528):306-11
references.pmid: 11452127
references.citation: Nature. 2001 May 10;411(6834):207-11
references.pmid: 11346799
references.citation: Adv Cancer Res. 2008;100:35-83
references.pmid: 18620092
references.citation: J Biol Chem. 2011 Sep 23;286(38):33335-44
references.pmid: 21828049
references.citation: J Immunol. 1999 Mar 15;162(6):3498-503
references.pmid: 10092806
references.citation: Mol Cancer Ther. 2011 Oct;10(10):1763-73
references.pmid: 21933973
references.citation: Cell. 2007 Dec 14;131(6):1039-41
references.pmid: 18083093
references.citation: Curr Opin Immunol. 2012 Dec;24(6):651-7
references.pmid: 23131610
references.citation: Clin Immunol. 2010 Aug;136(2):236-44
references.pmid: 20444650
references.citation: Arthritis Rheum. 1992 Jun;35(6):630-40
references.pmid: 1599520
references.citation: J Exp Med. 2008 Jan 21;205(1):219-32
references.pmid: 18195070
references.citation: J Immunol. 2008 Jun 1;180(11):7728-35
references.pmid: 18490777
references.citation: Curr Opin Immunol. 2010 Dec;22(6):740-6
references.pmid: 21030229
references.citation: Arthritis Rheum. 2012 Aug;64(8):2677-86
references.pmid: 22553077
references.citation: J Immunol. 2007 May 1;178(9):5635-42
references.pmid: 17442946
references.citation: Arthritis Res Ther. 2011 Apr 15;13(2):R62
references.pmid: 21496228
references.citation: Nat Rev Rheumatol. 2010 May;6(5):280-9
references.pmid: 20431553
references.citation: Cell. 2007 Dec 14;131(6):1124-36
references.pmid: 18083102
references.citation: J Immunol. 2013 Feb 15;190(4):1433-46
references.pmid: 23319738
references.citation: Ann N Y Acad Sci. 2010 Oct;1209:23-9
references.pmid: 20958312
references.citation: J Exp Med. 2002 Jul 1;196(1):135-40
references.pmid: 12093878
references.citation: Arthritis Res Ther. 2010;12(4):R146
references.pmid: 20637106