From studies of BAL cells we know that lung accumulated immune cells are activated in sarcoidosis patients [3,4], further, accumulations of CD4+ cells expressing the T cell receptor (TCR) V gene segment Vα2.3+ are accumulated in BAL fluid (BALF) of HLA DRB1*03+ patients, often with Löfgren’s syndrome [5]. Here, CD4 is linked to sarcoidosis.