Analysis of BATF transcript and PD-1 protein expression in sarcoidosis CD4+ T cells revealed a positive relationship between BATF and PD-1, such that sarcoidosis subjects with high PD-1 upregulation also express higher levels of BATF (Figure 8(b); r = 0.56, p = 0.02). The gene discussed is CD4; the disease is sarcoidosis.