Some HIV-1 infected patients are unable to completely recover normal CD4+ T-cell counts after achieving HIV-1 suppression with combined antiretroviral therapy, hence being classified as immune-discordant. A new study, published in the Frontiers in Immunology journal and leaded by IrsiCaixa AIDS Research Institute in the framework of the EU-funded MISTRAL project, shows that prebiotic and probiotic supplementation is associated with a higher increase in CD4+/CD8+ T-cell ratio. In contrast, the administration of probiotic alone did not achieve any impact on immune parameters or faecal microbiome composition.
One of the key aspects of HIV infection is a fast and widespread destruction of CD4+ T-lymphocytes, which becomes more exacerbated in the latest stages of infection. An important fraction of HIV-infected people will become immunodiscordant, as they fail to fully recover CD4+ counts and immune function. “We wanted to assess if a novel probiotic, called i3.1 and developed by AB-Biotics, was safe and able to improve immune reconstitution in HIV-1 infected immuno-discordant patients with stable cART”, explains Marc Noguera-Julian, associate researcher at IrsiCaixa during the course of the study.
Probiotic supplementation is safe and can potentially induce immune parameters when administered with prebiotics
To understand the role of the probiotic in the immune reconstitution, researchers designed a double-blind placebo-controlled clinical trial called RECOVER. The study included 71 patients that were randomized to placebo, probiotic or probiotic+prebiotic (synbiotic), and were followed over 6 months + 3-month washout period, in which changes on systemic immune status and gut microbiome were evaluated.
Both probiotics and prebiotics contained the strains of Lactobacillus platarum and Pediococcus acidilactici, combined with prebiotic fivers. Although all interventions were found to be safe, efficacy varied between them, with synbiotic supplementation showing the greatest change in immune parameters. “We observed small increases in CD4/CD8 ratio and minor reductions in sCD14, but such changes are of uncertain clinical significance”, notes Carlos Blázquez-Bondia, predoctoral researcher at IrsiCaixa and first author of the scientific article.
The results motivate the research team to continue studying the effect of probiotics on immunity in people living with HIV with the aim of finding a therapeutic strategy that exploits their immunomodulatory potential.