Several cytokines (CX3CR1, CCL5, C3AR1, PSAP, GNG11, PF4, CCR2, GPR183, and CXCL16) are involved in the polarization of macrophages or the inflammatory response and may also be associated with the inflammatory regulation of pulmonary hypertension. The gene discussed is CXCL16; the disease is pulmonary arterial hypertension.