{
  "abstract": "Background HPV anorectal infection is the main cause of anal cancer in people living with HIV (PLWH). Data on HPV-specific T-cell responses to the nonavalent vaccine in PWH are limited. Given the critical role of cell-mediated immunity (CMI) in vaccine efficacy, we evaluated post-vaccination T-cell responses in PWH on Anti-retroviral Therapy (ART), from first vaccine dose until up to two years after vaccination.Materials and Methods We prospectively enrolled PWH on ART. Inclusion criteria were age ≥18 years, undergoing ART for at least 6 months, and naïve to HPV vaccination. Gardasil9 was administered at baseline (T0), after 2 and 6 months (T1); follow-up continued to 6 months (T2) up to 2 years (T3). We performed anal swabs for HPV DNA, and blood samples were collected for viro-immunological follow-up and to evaluate CMI by flow cytometry of CD4 and CD8 T cells producing IFN-γ, IL-2, or TNFα (responding cells) or all three cytokines (polyfunctional cells) after stimulation with a pool of HPV16 and 18 L1 peptides. Adjusted linear mixed models with random intercepts and slopes for individuals and robust standard errors were used to estimate mean levels of CD4 and CD8 responding and polyfunctional cells comparing groups stratified by baseline CD4(>500 vs ≤500 cells/μL) and prior HPV infection, documented by consulting all available clinical records collected prior to study. Models were adjusted for age, sex, CD4 nadir, HIV viral load suppression and CD4 at baseline.Results A total of 38 patients were enrolled; clinical characteristics are shown in table 1. Current T3 data were available for 31 patients out of 38 (82%). HIV viro-immunological control was maintained through T3, as shown in table 2. At T3, anorectal infection with at least one high-risk (HR) HPV genotype was detected in 22 out of 31 patients (71%), with a median number of HR genotypes of 2 (IQR 1–4), and a median of low risk (LR) genotypes of 1 (IQR 0–2). HPV16 infection had the highest prevalence among HR genotypes isolated (7/31 patients, 22,6%) as shown in graph 1. Concerning T-cell responses, at T1 participants with >500 CD4 cells/μl showed significantly greater increases in CD4-responding, CD4-polyfunctional, and CD8-responding cells compared to those with ≤500 CD4 cells/μl. At T2, a significant difference persisted for CD8-responding cells. By T3, most differences were no longer significant, except for CD8-polyfunctional cells, which showed a significant decrease in the >500 CD4 group compared to the ≤500 group (table 3). When stratifying the population by previous HPV infection, no significant differences emerged between the two subgroups.Conclusions In PLWH, baseline CD4 counts ≥500/mmc are associated with stronger early immune responses to HPV vaccination with a significant increase of CD4+ and CD8+ polyfunctional T cells in comparison with PWH with <500 CD4+. Tailored vaccination schedules and follow-up may be warranted to ensure optimal and sustained protection.Abstract SC15 Table 1–3 and Graph 1",
  "authors": [
    {
      "affiliations": [
        "Infectious Diseases Unit, S.M. Goretti Hospital, Latina, Italy",
        "PhD course in Microbiology, Immunology, Infectious Diseases, and Transplants (MIMIT), University of Rome Tor Vergata, Rome, Italy"
      ],
      "name": "L Ansaldo"
    },
    {
      "affiliations": [
        "Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy"
      ],
      "name": "E Tortellini"
    },
    {
      "affiliations": [
        "Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy",
        "Department of NESMOS, Sapienza University of Rome, Rome, Italy"
      ],
      "name": "MS Guardiani"
    },
    {
      "affiliations": [
        "Infectious Diseases Unit, S.M. Goretti Hospital, Latina, Italy"
      ],
      "name": "S Corazza"
    },
    {
      "affiliations": [
        "Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy"
      ],
      "name": "A Carraro"
    },
    {
      "affiliations": [
        "Infectious Diseases Unit, S.M. Goretti Hospital, Latina, Italy"
      ],
      "name": "G Mancarella"
    },
    {
      "affiliations": [
        "Infectious Diseases Unit, S.M. Goretti Hospital, Latina, Italy"
      ],
      "name": "M De Masi"
    },
    {
      "affiliations": [
        "Infectious Diseases Unit, S.M. Goretti Hospital, Latina, Italy"
      ],
      "name": "D Di Trento"
    },
    {
      "affiliations": [
        "Infectious Diseases Unit, S.M. Goretti Hospital, Latina, Italy"
      ],
      "name": "A Gasperin"
    },
    {
      "affiliations": [
        "Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy",
        "Microbiology and Virology Unit, Policlinico Umberto I, Sapienza University of Rome, Rome, Italy"
      ],
      "name": "MA Zingaropoli"
    },
    {
      "affiliations": [
        "Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy"
      ],
      "name": "F Dominelli"
    },
    {
      "affiliations": [
        "Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy"
      ],
      "name": "M Proietti"
    },
    {
      "affiliations": [
        "UOS Profilassi e Sorveglianza Malattie Infettive, S.M. Goretti Hospital, Latina, Italy"
      ],
      "name": "C Giambi"
    },
    {
      "affiliations": [
        "Department of Clinical Pathology, S. M. Goretti Hospital, Latina, Italy"
      ],
      "name": "M Tagliaferro"
    },
    {
      "affiliations": [
        "Department of Clinical Pathology, S. M. Goretti Hospital, Latina, Italy"
      ],
      "name": "U Basile"
    },
    {
      "affiliations": [
        "Infectious Diseases Unit, S.M. Goretti Hospital, Latina, Italy"
      ],
      "name": "R Marocco"
    },
    {
      "affiliations": [
        "Infectious Diseases Unit, S.M. Goretti Hospital, Latina, Italy"
      ],
      "name": "C Del Borgo"
    },
    {
      "affiliations": [
        "Department of NESMOS, Sapienza University of Rome, Rome, Italy"
      ],
      "name": "M Lichtner"
    }
  ],
  "title": "SC15 Baseline CD4 count influences HPV vaccine response in people living with HIV: two-year follow-up",
  "uid": "f159cdca-5d08-5f65-9411-406cd7ecda2d"
}