CXCL5 and depressive disorder: Previous studies have shown that anxiety was associated with low levels of many cytokines in sera, such as CCL11, CCL2, CCL5, and IL-6; and lower peripheral levels of CXCL5 was observed in people with psychiatric disorders, such as schizophrenia and recurrent depressive disorder with suicidal ideation (Polacchini et al., 2018).