Epstein-Barr virus antibodies and severity of depression

Infectious mononucleosis as a risk factor for depression: A nationwide cohort study

BACKGROUND

Infectious mononucleosis is a clinical diagnosis characterized by fever, sore throat, lymph node enlargement and often prolonged fatigue, most commonly caused by Epstein-Barr virus infection. Previous studies have indicated that infectious mononucleosis can be followed by depression; however, large-scale studies are lacking. We used nationwide registry data to investigate the association between infectious mononucleosis and subsequent depression in this first large-scale study.

METHODS

Prospective cohort study using nationwide Danish registers covering all 1,440,590 singletons born (1977-2005) in Denmark by Danish born parents (21,830,542 person-years' follow-up until 2016); where 12,510 individuals had a hospital contact with infectious mononucleosis. The main outcome measures were a diagnosis of major depressive disorder (ICD-8: 296.09, 298.09, 300.4; ICD-10: F32) requiring hospital contact.

RESULTS

Infectious mononucleosis was associated with a 40% increased hazard ratio (HR) for a subsequent depression diagnosis in the fully adjusted model (HR: 1.40, 95% CI: 1.26-1.56;n = 358), when compared to unexposed individuals. The increased risk of being diagnosed with depression was significant to the periods one to four years after the infectious mononucleosis diagnosis (HR: 1.40, 95% CI: 1.17-1.67;n = 121) and ≥ five years (HR: 1.40, 95% CI: 1.22-1.61;n = 207). We did not find any differences according to age (p = 0.61) nor sex (p = 0.30).

CONCLUSION

In this largest study to date, infectious mononucleosis in childhood or adolescence was associated with an increased risk of a subsequent depression. Our findings have important clinical implications and identifies youth with infectious mononucleosis as a group at high risk of later depression in young adulthood.

Hypothesis: bipolar disorder is an Epstein-Barr virus-driven chronic autoimmune disease - implications for immunotherapy

Bipolar disorder (BD) is a chronic disease characterised by episodes of major depression and episodes of mania or hypomania, with a worldwide prevalence of 2.4%. The cause of BD is unknown. Here, I propose the hypothesis that BD is a chronic autoimmune disease caused by Epstein–Barr virus (EBV) infection of autoreactive B cells. It is postulated that EBV‐infected autoreactive B cells accumulate in the brain where they provide costimulatory survival signals to autoreactive T cells and differentiate into plasma cells producing pathogenic autoantibodies targeting brain components such as the N‐methyl‐D‐aspartate receptor. It is also proposed that the accumulation of EBV‐infected autoreactive B cells in the brain is a consequence of a genetically determined defect in the ability of CD8⁺ T cells to control EBV infection. The theory is supported by studies indicating that autoimmunity, EBV infection and CD8⁺ T‐cell deficiency all have roles in the pathogenesis of BD. According to the hypothesis, BD should be able to be treated by EBV‐specific T‐cell therapy and to be prevented by vaccination against EBV in early childhood. Exposure to sunlight or appropriate artificial light should also be beneficial in BD by augmenting CD8⁺ T‐cell control of EBV infection.

Meta-analysis of infectious agents and depression

Depression is a debilitating psychiatric disorder and a growing global public health issue. However, the relationships between microbial infections and depression remains uncertain. A computerized literature search of Medline, ISI Web of Knowledge, PsycINFO, and the Cochrane Library was conducted up to May 2013, and 6362 studies were initially identified for screening. Case-control studies detected biomarker of microorganism were included. Based on inclusion and exclusion criteria, 28 studies were finally included to compare the detection of 16 infectious agents in unipolar depressed patients and healthy controls with a positive incident being defined as a positive biochemical marker of microbial infection. A customized form was used for data extraction. Pooled analysis revealed that the majority of the 16 infectious agents were not significantly associated with depression. However, there were statistically significant associations between depression and infection with Borna disease virus, herpes simplex virus-1, varicella zoster virus, Epstein-Barr virus, and Chlamydophila trachomatis.

Infecções virais e depressão

OBJETIVO: A associação entre depressão e viroses é estudada há quase dois séculos, com resultados conflitantes. O objetivo deste trabalho é fazer uma análise crítica dos estudos existentes na literatura sobre essa relação. MÉTODOS: A pesquisa bibliográfica utilizou as fontes eletrônicas de busca MEDLINE e LILACS (1966 a agosto 2005). As referências dos artigos foram utilizadas como fonte adicional de consulta. RESULTADOS: Foram abordados os trabalhos que trataram da associação entre depressão e os vírus HIV, HCV, EBV, influenza, HSV, HBV, HAV, BDV e HTLV. A relação entre HIV e depressão mostrou-se bem documentada na literatura. Existem indícios de que a prevalência desse transtorno nos indivíduos infectados pelo HIV seja maior que a encontrada nos soronegativos. Além disso, estudos constataram que a depressão está associada a pior prognóstico da infecção. Quanto à associação entre HCV e depressão, os trabalhos sugeriram maior prevalência desse transtorno psiquiátrico nos portadores do HCV comparados à população geral. Não existem evidências científicas suficientes para dar suporte à relação entre os demais vírus e depressão. CONCLUSÃO: As associações mais bem fundamentadas foram aquelas entre depressão e os vírus HIV e HCV. A relação entre as demais viroses e depressão precisa ser mais bem estudada, e trabalhos com delineamento adequado se fazem necessários.

Depressive symptoms in the elderly: association with total white blood cell count

1. The white blood cell (WBC) count in those with high depressive symptoms and non-depressed participants in the Established Populations for Epidemiologic Studies of the Elderly (EPESE) were compared. 2. Of 3769 participants 10.8% had high depressive symptoms as assessed by the Centers for Epidemiologic Studies Depression (CES-D) Scale. The mean white blood cell count was higher in the high depressive symptoms group compared to the non-depressed group (6.8 +/- 0.12 x 10(9) WBC/1 and 6.5 +/- 0.03 x 10(9) WBC/1, respectively, p < 0.01). 3. Because older adults frequently have disabling chronic conditions which could both influence their leukocyte count and cause depressive symptoms, models were developed which controlled for the potential confounding. Even after adjusting for potential confounders, high depressive symptoms were still associated with higher white blood cell counts.