Meanwhile, some studies obtained lymphocytes from the bronchoalveolar lavage fluid of silicosis patients and found that apoptosis-related receptors increased by more than 20% and apoptosis-related ligands were highly expressed on CD4+ T and CD8+ T cells; namely, the degree of apoptosis of CD4+ T and CD8+ T cells increased (24). The gene discussed is CD4; the disease is silicosis.