Human cytomegalovirus genome sequences in lymph nodes

Area of Science:

• Virology
• Immunology
• Transplant Medicine

Background:

• Human cytomegalovirus (CMV) is a significant cause of morbidity in heart and lung transplant recipients.
• CMV reactivation, often due to immunosuppression, can originate from the donor tissue or the recipient.
• Latent CMV reservoirs contribute to post-transplant complications.

Purpose of the Study:

• To investigate the role of lymph nodes (LNs) as a reservoir for latent human cytomegalovirus (CMV) in transplant patients.
• To determine if CMV presence in LNs correlates with earlier viral reactivation (viraemia).
• To assess the significance of LNs in CMV persistence and dissemination.

Main Methods:

• Analysis of CMV DNA and RNA levels in donor and recipient lymph nodes and matched blood samples.
• Comparison of viral detection in LNs versus blood samples.
• Longitudinal follow-up of patients to monitor for viraemia development.

Main Results:

• CMV DNA was detected at higher levels in LNs of both donors and recipients compared to blood.
• CMV RNA, undetectable in blood, was found in LNs of some CMV-seropositive individuals.
• Patients with CMV DNA and RNA in LNs developed viraemia 4-5 weeks earlier than those negative for CMV in LNs.

Conclusions:

• Lymph nodes serve as a significant site for CMV sequestration and persistence.
• The presence of CMV in LNs may indicate an increased risk of early viraemia post-transplantation.
• LNs might play a crucial role in the seeding of CMV-infected cells into the bloodstream.