Diminished response to tick-borne encephalitis vaccination in thymectomized children

Area of Science:

• Immunology
• Vaccinology
• Pediatric Medicine

Background:

• The thymus plays a crucial role in T cell development and immune system maturation.
• Understanding the long-term immunological consequences of thymectomy in children is essential for predicting health outcomes.

Purpose of the Study:

• To assess the clinical impact of thymectomy on immunological alterations in children.
• To analyze the immune response to a new antigen (tick-borne encephalitis virus vaccine) in thymectomized children compared to healthy controls.

Main Methods:

• 17 thymectomized children received a three-dose tick-borne encephalitis virus (TBEV) vaccine.
• Antibody levels (TBEV IgG) and T cell subsets (naïve T cells) were measured.
• Data were compared to 30 healthy age-matched controls.

Main Results:

• Thymectomized children had lower TBEV IgG levels after the second vaccine dose (p=0.03), but a normal response after the third dose.
• Age at thymectomy correlated with TBEV IgG levels (p=0.04).
• Lower total counts and percentages of naïve T cells were observed in thymectomized children, correlating with time post-thymectomy (p=0.02).

Conclusions:

• Thymectomy in children can lead to transiently reduced immune responses to new antigens.
• Alterations in T cell subsets suggest potential long-term immune dysregulation.
• These findings may indicate increased susceptibility to infections or autoimmune conditions later in life.