Copyright ©The Author(s) 2015.
World J Nephrol. Sep 6, 2015; 4(4): 455-467
Published online Sep 6, 2015. doi: 10.5527/wjn.v4.i4.455
Table 1 Common genetic determinants for immunoglobulin A nephropathy
Genetic locusGenesFunction
6q21HLA-DRB1, HLADQA1 and HLA-DQB1Class II major histocompatibility complex
PSMB8/9 and TAP/2Regulators for antigen processing and presentation
1q32CFHR1/3Modulators for complement activation and inflammation
17q13TNFSF13Important for B cell development and IgA isotype switching
8p23DEFA1Encoding a-defensins as a type of endogenous antimicrobial mediators
1p13VAV3Regulators for lymphocyte development and antigen presentation
9q34CARD9Participant in antigen-induced signalosome formation (CARD9-BCL 10-MALT1) and NF-κB activation
16p11ITGAM and ITGAXMediators for immune cell adhesion and phagocytosis
Table 2 Summary of the four hits involved in the pathogenesis of immunoglobulin A nephropathy with distinction of the pathogenetic process (putative environmental factors involved, putative genetic factors involved, potential clinical biomarkers and potential novel therapeutic approaches)
HitPathogenic processPutative environmental factors involvedPutative genetic factors involvedPotential clinical biomarkersPotential novel therapeutic approaches
1Hereditary increase in circulating galactose-deficient IgA1Potential role of mucosal exposure to infectious of dietary antigensStrong evidence for high heritability of serum galactose-deficient IgA1 level Potential role of chromosome 22q12.2Serum galactose-deficient IgA1 level (HAA-based ELISA)Suppression of synthesis of galactose-deficient IgA1 Enzymatic boost of galactose transfer to IgA1 hinge- region O-glycans Suppression of sialylation of galactose-deficient O-glycans
2Circulating antibody directed against galactose-deficient IgA1Potential role of mucosal exposure to infectious or dietary antigensPotential role of three MHC-II loci in antigen presentation and humoral response to galactose-deficient IgA1 O-glycansSerum anti-glycan antibodies (dot blot assay)Alteration of processing and presentation of galactose-deficient IgA1 O-glycopeptides Specific B-cell depletion therapy
3Formation of pathogenic IgA1-containing immune complexesUnknownUnknownCirculating and/or urinary immune complexesCompetitive blockade of immune complex formation by non-cross-linking anti-glycan antibodies or specific glycopeptides
4Mesangial deposition of IgA1 containing immune complexes, cell activation and initiation of glomerular injuryUnknownProtective effect of common deletion in CFHR1 and CFHR3Circulating and/or urinary complement degradation products, or novel markers of glomerular injurySuppression of the alternative complement pathway Targeted CFHR1/3 depletion Blocking mesangial cell signaling induced by nephritogenic IgA1-containing immune complexes