Immunosenescence is associated with human cytomegalovirus and shortened telomeres in type I bipolar disorder.

OBJECTIVE:

Bipolar disorder (BD) has been associated with
persistent low-grade inflammation and premature cell senescence, as
shown by reduced telomere length (TL). The human cytomegalovirus (CMV)
has increasingly been implicated in accelerated immunosenescence in
aging studies. Here, we compared CMV serology and its relationships with
cell senescence markers, including TL and lymphocyte subsets, in
patients with type I BD and healthy controls.

METHODS:

Twenty-two
euthymic female patients with BD type I and 17 age-matched healthy
controls were selected for the study. A sample of blood was collected
and mononuclear cells and DNA were isolated and TL measured. CMV
immunoglobulin M (IgM) and IgG titers were measured using
chemiluminescent assays. Lymphocyte subsets [T, natural killer (NK) and
NKT] were phenotyped by flow cytometry.

RESULTS:

Individuals
with BD had shorter TLs but higher CMV IgG levels than controls (both p
< 0.01). CMV IgG level was inversely correlated with TL. None of the
subjects showed IgM reactivity for CMV, excluding acute viral
infection. CMV IgG level was associated with expansion of senescent
CD8+CD28- T cells and NK cells, which are involved in viral control.

CONCLUSIONS:

These
data support the hypothesis of accelerated aging in BD, as shown by
shortened telomeres, higher seropositivity for CMV, and expansion of
senescent T cells.