Nettis et al. conducted a 4-week, placebo-controlled, randomized clinical trial of minocycline (200 mg/d) added to antidepressant therapy in 39 patients selected for elevated levels of serum C-reactive protein (CRP ≥ 1 mg/L); the authors found efficacy of add-on minocycline therapy in patients with major depressive disorder, but only in those with low grade inflammation defined as CRP ≥ 3 mg/L (95). The gene discussed is CRP; the disease is major depressive disorder.