CCR4 and pulmonary sarcoidosis: While evaluating the surface chemokine receptor expression on central memory Tfh cells, it was found that in pulmonary sarcoidosis peripheral blood samples contained an elevated percentage of Tfh2 (CXCR3 − CCR6 − CCR4+), Tfh17 (CXCR3 − CCR6 + CCR4+), and dual-positive Tfh17 (CXCR3 + CCR6 + CCR4+) paralleled with significantly reduced Tfh1 (CXCR3 + CCR6 − CCR4−) and Tfh17.1 (CXCR3 + CCR6 + CCR4−) levels [I. (42)].