APOA1 and diabetic kidney disease: Among the highest contributing proteins in the chosen components and peaks in diabetic nephropathy, impaired renal function and other diseases were the following: transthyretin, apolipoprotein C1 (apo C1), apolipoprotein A1 (apo A1) and cystatin C. The identities of these proteins were confirmed by immunoprecipitation and sequencing or western blots.