Cumulative incidence of IFN-γ⁺ and IFN-γ⁺/IL-2⁺ CD4⁺ and CD8⁺ T-cell recovery in HSCT recipients.

<p>(A) HCMV-seropositive and (D) HCMV-seronegative young HSCT recipients. The cumulative curve indicating levels of protection during follow-up is also reported. Five (20%) of the 25 patients who developed HCMV-specific CD8+ T-cell response only a median time of 57 (16–340) days prior to appearance of CD4+ T-cells, had high DNAemia levels requiring antiviral treatment. The correlation (Spearman correlation test) between time to protection by HCMV-specific (B) CD4⁺ or (C) CD8⁺ T-cells and time to HCMV clearance from blood is shown. Within 12 months after transplantation, 95/131 patients developed specific T-cell immunity: 2 CD8+ only, and 93 both CD4 and CD8 T-cells. Of these 93, 85 developed specific immunity above the cutoff levels established for immune compromised patients (but 5 required antiviral treatment because of steroid therapy for GvHD), and 8 only levels above the cutoffs established for immune competent subjects (and were found to be also protected from reactivation).</p

Cumulative incidence of HCMV infection in 131 young patients receiving HSC transplantation.

<p>(A) HCMV-seropositive patients. (B) HCMV-seronegative patients. (C) HCMV viral load in 88 patients with self-resolving or no HCMV infection, and in 43 patients requiring antiviral treatment. Among patients receiving T-cell depleted transplantation (TCD), 14/28 were included in the pre-emptive treatment group. Similarly, 10/11 patients receiving cord blood transplantation (CBT) were included in the pre-emptive treatment group.</p

Probability of survival, transplant-related mortality and GvHD in the HSCT studied population.

<p>(A) event-free survival (EFS), (B) overall survival (OS): no significant difference was found by the log-rank test. (C) Transplantation–related mortality (TRM), and (D) acute and chronic GvHD were expressed as cumulative incidence, taking into account the appropriate competing risks: no difference was found by the Gray test. HCMV-seropositive and HCMV-seronegative young HSCT recipients are reported separately.</p

Characteristics of the 131 patients analyzed.

<p>TBI: total body irradiation; GvHD: graft <i>vs</i> host disease; CS-A: cyclosporine-A; MTX:methotrexate; ALG: anti-lymphocyte globulin methotrexate; ALG: anti-lymphocyte globulin.</p>*<p>Among patients with malignant disease.</p

Flow-chart of HCMV-specific T-cell response.

<p>Immune control of HCMV infection in the 131 young patients enrolled in the study. During follow-up, 12/42 HCMV-seronegative and 89/89 HCMV-seropositive patients developed HCMV infection/immunity, for a total of 101 patients. Forty-three patients required pre-emptive therapy to control HCMV infection prior to development of specific immunity. Six patients died for underlying disease relapse. Of the 93 remaining patients, 88 (95%) were protected, while 5 (5%) were treated with additional courses of pre-emptive therapy because the steroid therapy employed for treating GvHD promoted reactivation of viral infection, with a viral load in blood reaching the established cutoff.</p

HCMV-specific T-cell response to HCMV infection in 4 young patients receiving HSCT transplantation.

<p>(A) Early specific CD4⁺and CD8⁺ T-cell response with no HCMV infection. (B) Delayed CD4⁺ and CD8⁺ T-cell response with high viral load in a patient pre-emptively treated. (C) Early CD8⁺ T-cell response which did not prevent HCMV infection until HCMV-specific CD4⁺ response appeared. (D) In the presence of acute and chronic GvHD requiring steroid treatment, specific immune reconstitution did not protect against HCMV infection, which required ganciclovir (GCV) treatment, and was eventually prevented by a protective CD4⁺ and CD8⁺ T-cell response.</p

Fetal Human Cytomegalovirus Transmission Correlates with Delayed Maternal Antibodies to gH/gL/pUL128-130-131 Complex during Primary Infection

<div><p>Primary human cytomegalovirus (HCMV) infections during pregnancy are associated with a high risk of virus transmission to the fetus. To identify correlates of intrauterine HCMV transmission, serial serum samples from HCMV transmitter and non-transmitter pregnant women with primary HCMV infection were analyzed for the presence of neutralizing antibodies against different glycoproteins and glycoprotein complexes, which are known to mediate entry into distinct types of host cells. Neutralizing activity was detected in the sera early after primary infection; absorption with a soluble pentameric complex formed by gH/gL/pUL128-131, but not with gH/gL dimer or with gB, abolished the capacity of sera to neutralize infection of epithelial cells. Importantly, an early, high antibody response to pentamer antigenic sites was associated with a significantly reduced risk of HCMV transmission to the fetus. This association is consistent with the high <i>in vitro</i> inhibition of HCMV infection of epithelial/endothelial cells as well as cell-to-cell spreading and virus transfer to leukocytes by anti-pentamer antibodies. Taken together, these findings indicate that the HCMV pentamer complex is a major target of the antibody-mediated maternal immunity.</p> </div

Frequencies of CD4⁺ and CD8⁺ T cells specific for HCMV proteins IE-1, pp65, gHgLpUL128L (pentamer) and gB in the naïve pool of HCMV-seronegative subjects and in the memory pool of subjects with primary or remote HCMV infection.

<p><b>A, B.</b> Frequencies of protein-specific <b>(A)</b> CD4⁺ and <b>(B)</b> CD8⁺ naïve T cells in 6 HCMV-seronegative subjects are reported. Each symbol represents an individual and horizontal black lines indicate median values. <b>C, D.</b> Frequencies of protein-specific <b>(C)</b> CD4⁺ and <b>(D)</b> CD8⁺ memory T cells in 6 patients with primary HCMV infection tested within one month and 6–12 months after infection onset. <b>E, F.</b> Frequencies of protein-specific <b>(E)</b> CD4⁺ and <b>(F)</b> CD8⁺ memory T cells in 7 subjects with remote HCMV infection are reported.</p

Virological and immunological monitoring of the four groups of solid-organ transplant recipients with or without HCMV infection reactivation.

<p>NA, not applicable.</p>1<p>Follow-up.</p>2<p>Patients of this group showed HCMV specific CD8⁺ only, until about 3 months after transplantation, then developed HCMV-specific CD4⁺ T-cells.</p>3<p>In some cases, clinicians preferred initiating antiviral therapy after reaching 100,000 (instead of 300,000) DNA copies/ml blood due to presence of end-organ disease.</p><p>Virological and immunological monitoring of the four groups of solid-organ transplant recipients with or without HCMV infection reactivation.</p

Comparison of (A) HCMV-specific and (B) total T-cells/µl in group 4 non-protected patients <b><i>vs</i></b><b> groups 1+2+3 protected patients.</b>

<p>While both total and HCMV-specific CD4⁺ T-cells are significantly higher in protected patients, no difference is observed between protected and non-protected patients for both total and specific CD8⁺ T-cells.</p