Effect of cytomegalovirus co-infection on normalization of selected T-cell subsets in children with perinatally acquired HIV infection treated with combination antiretroviral therapy

Incomplete immune reconstitution in HIV/AIDS patients on antiretroviral therapy: Challenges of immunological non-responders

The morbidity and mortality of HIV type-1 (HIV-1)-related diseases were dramatically diminished by the grounds of the introduction of potent antiretroviral therapy, which induces persistent suppression of HIV-1 replication and gradual recovery of CD4⁺ T-cell counts. However, ∼10-40% of HIV-1-infected individuals fail to achieve normalization of CD4⁺ T-cell counts despite persistent virological suppression. These patients are referred to as "inadequate immunological responders," "immunodiscordant responders," or "immunological non-responders (INRs)" who show severe immunological dysfunction. Indeed, INRs are at an increased risk of clinical progression to AIDS and non-AIDS events and present higher rates of mortality than HIV-1-infected individuals with adequate immune reconstitution. To date, the underlying mechanism of incomplete immune reconstitution in HIV-1-infected patients has not been fully elucidated. In light of this limitation, it is of substantial practical significance to deeply understand the mechanism of immune reconstitution and design effective individualized treatment strategies. Therefore, in this review, we aim to highlight the mechanism and risk factors of incomplete immune reconstitution and strategies to intervene.

CMV+ Serostatus Associates Negatively with CD4:CD8 Ratio Normalization in Controlled HIV-Infected Patients on cART

Cytomegalovirus (CMV) infection is common among HIV-infected patients but its repercussion on the course of CD4+ and CD8+ T cells after cART initiation remains elusive. The French Dat'AIDS cohort enrolled 5,688 patients on first-line cART, from which we selected patients who achieved HIV suppression for at least 12 months without modification of cART, and for whom CMV serostatus was available. Five hundred and three patients fulfilled the selection criteria (74% male, median age 43 yrs, 15.5% CDC stage C), of whom 444 (88.3%) were seropositive for CMV (CMV+). Multivariate analyses using mixed-linear models adjusted for the time from HIV suppression, sex, age, transmission risk group, duration of HIV follow-up, the interaction between time from HIV suppression and CMV+ serology, and the nadir CD4 count revealed a negative correlation between CMV+ and CD4:CD8 ratio (coeff. = -0.16; p = 0.001). This correlation was also observed among patients displaying optimal CD4 recovery (≥500 cells/mm3 at M12; coeff. = -0.24; p = 0.002). Hence, CMV+ serostatus antagonizes normalization of the CD4:CD8 ratio, although further analyses of the impact of co-morbidities that associate with CMV serostatus, like HCV infection, are needed to elucidate this antagonism formally. However, this might reflect a premature T cell senescence, thus advocating for a close monitoring of T cells in CMV co-infected patients. In addition, our results raise the question of the benefit of treatment for asymptomatic CMV co-infection in HIV-infected patients.

Cytomegalovirus and paediatric HIV infection

Cytomegalovirus (CMV) was among the most common AIDS-defining illnesses prior to the advent of combination antiretroviral therapy (ART). In the ART era, CMV disease remains a significant public health threat among HIV-infected adults and children with delayed HIV diagnosis. CMV co-infection may additionally contribute to accelerated HIV progression, development of inflammation-related comorbidities, immune senescence and developmental deficits. Elimination of CMV would have tremendous public health significance and is an important priority; however, current vaccine strategies are not targeted at HIV-infected individuals. Antivirals active against CMV may be a novel strategy to prevent acquisition and improve outcomes, but haematological side effects are common and necessitate cautious use in pregnant women and infants. Studies in HIV-infected children on ART lag behind adults, and the clinical significance of CMV in this population is not well understood. Furthermore, the effects of CMV in HIV-exposed uninfected (HEU) children need to be clarified to understand whether CMV interventions should also be a priority for this growing population. This review discusses our current understanding of CMV transmission and pathogenesis in HIV-exposed children and highlights unanswered questions for future research.