IL6 and depressive disorder: One study found associations between IL-6 and CRP, and the number of life events, which became non-significant when adding body mass index (BMI) as a covariate.28 Another study in adolescents found an association between childhood life events and IL-6 and CRP only in the group that developed depressive disorder 6 months later.29 A third study found an association between number of life events and CRP only when the adolescents had no positive engagement coping.30 Cellular immunity was also studied in adolescents, by measuring antibody levels to EBV.