FCGR2B and type 1 diabetes mellitus: In this study, we also examined the potential of FCGR2B as a candidate biomarker of disease progression, by comparing FCGR2B expression in peripheral blood RNA samples of T1D patients, AA+ individuals who later developed T1D (AA+ progressors), and AA- first-degree relatives of T1D patients (AA- FDRs) obtained from the National Institute of Health TrialNet repository.