The Immunology Of Suicidal Behavior

Introduction A recent study by Ahrens AP, et al. on university students with suicidal ideation has highlighted the connection between immunity and psychopathology, especially major depressive disorder (MDD) and suicidality [1-3]. This study has found that four major histocompatibility complex (MHC) alleles and the absence of oral microbe Alloprevotella rava increase the risk of suicidal behavior, emphasizing a microbial-genetic link in this pathology. Suicide is the second leading cause of mortality in young adults, contributing to more than 40,000 deaths per year in the US alone [4]. Previous studies have associated suicidal behavior with several alleles of the MHC, a network of genes encoding for the human leukocyte antigen (HLA). For example, the presence of DQB1*02 allele was reported to increase, while HLADQB1*05 to lower the odds of suicidal behavior, suggesting that genetics and immunity play a major role in the pathogenesis of this disorder [5].