Berylliosis is an environmental chronic inflammatory disorder of the lung caused by inhalation of beryllium dusts, characterized by the accumulation of CD4+ T cells and macrophages in the lower respiratory tract. Beryllium presentation to CD4+ T cells from patients with berylliosis results in T cell activation and these Be-specific CD4+ T cells undergo clonal proliferation and Th1-type cytokine production such as interleukin-2, interferon-gamma and tumor necrosis factor-alpha. In exposed workers, genetic susceptibility to this granulomatous disorder is associated with major histocompatibility gene and the TNF-alpha gene. The HLA-DP glutamic 69 residue was shown to be the MHC genetic marker associated with disease susceptibility; furthermore the TNF-alpha TNFA-308*2 allele was found to be independently associated with HLA-DP Glu69 in the determination of berylliosis risk.