Basic characteristics were entirely different such as CD4 cell count (209 cells/μL, range, 3–427 cells/μL versus 294 cells/μL, range, 29–465 cells/μL, p < 0.01) and psychiatric comorbidities (personality disorder, depression, psychotic disorder, and bipolar disorder, p < 0.01). This evidence concerns the gene CD4 and major depressive disorder.