Various meta-analyses and our own aforementioned study in the UK Biobank found that only 21-27% of depressed patients have ‘inflamed depression’ according to the CRP >3 mg/L criteria [2, 15], but the evidence reviewed here suggests that the proportion of immune-related MDD cases may be underestimated by analysing CRP only. The gene discussed is CRP; the disease is depressive symptom measurement.