Arvind singh

Complete summary and more of IgA nephropathy using mass spectrometry. 1. Majority of IgA is IgA1. 2. Smaller amounts of IgA2 are also present. 3. Both IgA1 and IgA2 colocalize with IgG, showing that the deposits are composed of IgA1/IgG and IgA2/IgG. 4. Dominant IgG subclass is IgG1. 5. J chain that binds monomers of IgA into dimers is present in majority of cases, indicating that the IgA is mucosal derived (as circulating IgA is monomer and doesn’t have J chain) 6. Absence of PIGR indicates that IgA is not derived from secretions such as saliva, tears, etc. PIGR is a peptide in IgA (present in secretions), that prevent the breakdown of IgA by bacteria. Taken together: IgA immune complexes in IgA nephropathy are made up of antigenic (galactose-deficient) mucosal-derived IgA and IgG. 7. Complement: Large amounts of C3 and C9 indicating alternative and terminal pathways of complement activation. 8. Minimal classical/no lectin pathway proteins. 9. Some correlation with MESTC score but bottom line= all IgA nephropathy shows lots of C3 and C9. 10. Abundant CFHR5 indicating that there is breakdown of C3 into inactive C3=iC3b. 11. Complement is a major player in the inflammatory process in IgA nephropathy. kidney-international.org/art…