Positive HCMV DNAemia in stem cell recipients undergoing letermovir prophylaxis is expression of abortive infection.

Letermovir (LMV) inhibits HCMV replication by binding to components of the HCMV-terminase complex showing a potential role in prevention of HCMV-related complications in allogenic hematopoietic stem cell transplant recipients (allo-HSCTRs). However, little is known about breakthrough HCMV infection and the relevance of HCMV DNAemia during prophylaxis. We reported the results of a multicenter prospective study involving five Italian centers in the management of HCMV DNAemia in 75 adult HCMV-seropositive allo-HSCTRs undergoing LMV prophylaxis. The aim of the present study was to characterize the presence of real HCMV reactivation during LMV prophylaxis. Then, the presence of circulating infectious HCMV particles was determined by virus isolation and degradation of free-floating viral DNA. This report provides the first evidence that during LMV prophylaxis the clinical relevance of HCMV DNAemia should be critically considered.

Reconstitution of Human Cytomegalovirus-Specific CD4+ T Cells is Critical for Control of Virus Reactivation in Hematopoietic Stem Cell Transplant Recipients but Does Not Prevent Organ Infection.

The relative contribution of human cytomegalovirus (HMCV)-specific CD4(+) and CD8(+) T cells to the control of HCMV infection in hematopoietic stem cell transplant (HSCT) recipients is still controversial. HCMV reactivation and HCMV-specific CD4(+) and CD8(+) T cell reconstitution were monitored for 1 year in 63 HCMV-seropositive patients receiving HSCT. HCMV reactivation was detected in all but 2 patients. In 20 of 63 (31.7%) patients (group 1) HCMV infection resolved spontaneously, whereas 32 of 63 (50.8%) patients (group 2) controlled the infection after a single short-course of pre-emptive therapy and the remaining 9 (14.3%) patients (group 3) suffered from relapsing episodes of HCMV infection, requiring multiple courses of antiviral therapy. The kinetics and magnitude of HCMV-specific CD8(+) T cell reconstitution were comparable among the 3 groups, but HCMV-specific CD4(+) T cells were lower in number in patients requiring antiviral treatment. HCMV-seronegative donors, as well as unrelated donors (receiving antithymocyte globulin) and acute graft-versus-host disease (GVHD) were associated with both delayed HCMV-specific CD4(+) T cell reconstitution and severity of infection. Conversely, these risk factors had no impact on HCMV-specific CD8(+) T cells. Eight patients with previous GVHD suffered from HCMV gastrointestinal disease, although in the presence of HCMV-specific CD4(+) and CD8(+) systemic immunity and undetectable HCMV DNA in blood. Reconstitution of systemic HCMV-specific CD4(+) T cell immunity is required for control of HCMV reactivation in adult HSCT recipients, but it may not be sufficient to prevent late-onset organ localization in patients with GVHD. HCMV-specific CD8(+) T cells contribute to control of HCMV infection, but only after HCMV-specific CD4(+) T cell reconstitution.

Nephrotic syndrome after allogeneic hematopoietic stem cell transplantation as a late complication of chronic graft-versus-host disease.

BACKGROUND: This study aims to determine the incidence and outcome of nephrotic syndrome in patients who underwent allogeneic stem cell transplantation in a single center. METHODS: Records of 279 adult patients with hematological diseases who underwent allogeneic hematopoietic stem cell transplantation were analyzed to evaluate the incidence and outcome of nephrotic syndrome. The diagnosis of chronic graft-versus-host disease was based on clinical evidence with histological confirmation whenever possible. RESULTS: Of the 279 patients, 105 with a minimum follow-up of 100 days developed chronic graft-versus-host disease: six of these had nephrotic syndrome. The cumulative incidence of nephrotic syndrome was 8% at day +1,681. Patients grafted with peripheral blood stem cells had a higher probability of developing nephrotic syndrome than did those grafted with bone marrow: 24% and 3%, respectively. The pathological diagnosis was membranous glomerulonephritis in four patients, and minimal change disease in one; the diagnosis could not be histologically confirmed in the sixth patient. All patients had extensive chronic graft-versus-host disease and were receiving treatment with cyclosporine A and steroids (four patients). Response to immunosuppressive therapy with cyclosporine A and steroids was achieved in all patients at a median time of 12 weeks after transplantation. CONCLUSION: Patients with chronic graft-versus-host disease may be considered to be at risk of nephrotic syndrome: careful monitoring of renal function is advisable, particularly in patients receiving allogeneic peripheral stem cell grafts.