Children with endemic Burkitt lymphoma are deficient in EBNA1-specific IFN-gamma T cell responses

Area of Science:

• Immunology
• Oncology
• Infectious Diseases

Background:

• Endemic Burkitt lymphoma (eBL) is a prevalent childhood cancer in equatorial Africa, strongly associated with Epstein-Barr virus (EBV) and Plasmodium falciparum coinfections.
• Epstein-Barr nuclear antigen 1 (EBNA1) is the only viral latent antigen present in BL tumors, making it a potential target for immune surveillance.
• A loss of EBNA1-specific immune surveillance is hypothesized to contribute to the development of eBL.

Purpose of the Study:

• To investigate EBNA1-specific T cell responses in Kenyan children with eBL compared to healthy children with varying malaria exposure.
• To determine if a selective defect in EBNA1-specific T cell immunity exists in eBL patients.
• To explore potential immunotherapeutic targets for EBV-associated eBL.

Main Methods:

• IFN-gamma ELISPOT assay was used to measure EBNA1-specific T cell responses.
• Humoral immunity to EBNA1 was assessed by measuring IgG(1) antibody responses.
• T cell responses to other EBV antigens and a malaria protein (merozoite surface protein 1) were also analyzed.

Main Results:

• Significantly fewer children with eBL (16%) exhibited EBNA1-specific IFN-gamma responses compared to healthy children (67-72%) (p < 0.003).
• Children with eBL maintained robust IgG(1) antibody responses to EBNA1, indicating intact humoral immunity.
• CD8(+) T cell responses to other EBV antigens and CD4(+) T cell responses to a malaria antigen were comparable between eBL patients and healthy controls.

Conclusions:

• Children with eBL exhibit a selective loss of EBNA1-specific T cell responses, while humoral immunity remains intact.
• This selective T cell defect suggests a potential mechanism for eBL development.
• Targeting EBNA1-specific T cell responses may offer a novel immunotherapeutic strategy for endemic Burkitt lymphoma.