Rising antigenemia levels may be misleading in pre-emptive therapy of human cytomegalovirus infection in allogeneic hematopoietic stem cell transplant recipients.

BACKGROUND AND OBJECTIVES Hematopoietic stem cell transplant (HSCT) recipients after show rising levels of antigenemia during pre-emptive ganciclovir treatment of human cytomegalovirus (HCMV) infection. This raises some doubts about the therapeutic decisions to be taken. DESIGN AND METHODS Three groups of HSCT recipients with HCMV infection undergoing anti-viral treatment were identified: group A, showing increasing antigenemia and decreasing viremia and DNAemia; group B, with simultaneous increases in antigenemia, viremia, and DNAemia; and group C, with decreasing levels of all 3 viral markers. Viral load, determined as levels of antigenemia, viremia and DNAemia, was monitored for 3 months post-transplantation in all groups. RESULTS Group A HSCT recipients showed antigenemia peaks 2-11 days after the onset of treatment, reaching negative levels only 25-30 days thereafter, whereas viremia and DNAemia started to drop earlier. Group B patients, mainly including HSCT recipients with grade II-IV acute GvHD treated with steroids prior to and during antiviral treatment, showed increasing levels of all three viral parameters until 5-10 days after the start of treatment; the levels dropped to negative values 25-30 days thereafter. Group C patients, who acted as controls, progressively cleared virus from blood as an early result of antiviral therapy. INTERPRETATION AND CONCLUSIONS Antigenemia is not the best assay to guide pre-emptive therapy. Group A patients, who have an isolated increase of antigenemia, do not require a change of the ongoing antiviral therapy. Whether better control of infection could be obtained in group B patients by either reducing immunosuppressive therapy (when possible) or adopting combination therapy remains to be determined.