RESUMO
BACKGROUND: The human cytomegalovirus (HCMV) causes severe complications in immunosuppressed patients, resulting in increased morbidity and mortality. The immunological components important for the control of HCMV are still not completely understood. OBJECTIVE AND STUDY DESIGN: To evaluate the importance of cellular and humoral immunity in stem cell transplant (SCT) recipients, we analysed levels of HCMV specific IFN-gamma producing CD4+ cells and glycoprotein B (gB) specific antibodies in HCMV positive SCT patients with and without reactivation episodes after SCT. RESULTS AND CONCLUSION: Patients without HCMV reactivation episodes showed a slow but steady increase in both parameters after SCT, indicating that initial high levels of gB specific antibodies or HCMV specific CD4+ IFN-gamma+ cells are not necessary to prevent reactivation of HCMV. In contrast, patients with reactivation episodes showed a steep, significant increase in HCMV specific CD4+ IFN-gamma+ counts just prior to HCMV reactivation, followed by a decline after the reactivation period. Patients who underwent only a single reactivation generated significant higher amounts of CD4+ IFN-gamma+ cells, than did patients with further reactivation episodes. The course of gB specific antibodies for reactivating patients was different, with significantly higher average values in the patients with HCMV reactivation. This indicates that patients with a HCMV reactivation exhibit a stronger humoral dominated immune response.
