To address whether CD4-targeted Bcl6 elimination prevents diabetes even when such a “T1D-poised” B cell repertoire has formed, we generated VH125SD.Bcl6fl/fl.NOD (termed VH125SD.NOD hereafter) and VH125SD Bcl6fl/fl.CreCD4.NOD (termed VH125SDBcl6ΔCD4) mice. The gene discussed is BCL6; the disease is diabetes mellitus.