The TLR9 in DCs recognize phagocytosed self-DNA and induce the expansion of pathogenic CD4+Th1 cells recognizing beryllium-modified HLA-DP2/peptide complex (beryllium-specific CD4+T cells) before the clinical development of pulmonary granulomas characterizing chronic beryllium disease (CBD) (204). Here, CD4 is linked to chronic beryllium disease.