S100A9 and type 1 diabetes mellitus: In another LC-MS/MS based study investigating early type 1 diabetes [29], eight of the ten proteins that gave rise to the most frequently observed peptides namely, albumin, collagen alpha-1(I) chain, hemoglobin subunit alpha, hemoglobin subunit beta, apolipoprotein A-I, protein S100-A9, collagen alpha-2(I) chain, uromodulin, were also included in the seventeen most frequent proteins in our study.