We conducted the hitherto largest meta-analysis comparing immune biomarkers between subjects with and without suicide attempt history or death by suicide. Data were based on 36 studies including 2679 persons with suicidal behaviors and 6839 comparison subjects, and four immune-related biomarkers (CRP, IL-6, TNF-? and IL-1?). Suicidal behavior was associated with higher CRP blood levels compared with: healthy controls; patients with depression alone and patients with any psychiatric disorders. IL-6 blood level was higher in patients with suicidal behaviors compared with healthy controls and when compared with psychiatric patients without suicidal behaviors. These results implicate the immune system and inflammatory response in suicidal behavior independent of a relationship to major psychiatric disorders, and that these biological measures are predominantly state-dependent markers.