Serum IgG1 and IgG4 could contribute to partial control of viral rebound in chronically HIV-1 infected patients
DOI for this work is: 10.1097/QAD.0000000000002944 Published in 2021 by Lucia Lopalco et al. All the enrolled patients studied in this work were previously described in the APACHE study. The study was conducted on HIV chronically infected patients, with HIV-RNA <50 cps/mL for ≥10 years, CD4+ cell count >500 cells/μL and HIV-DNA <100 copies/106 PBMC. The ART regimen in use at the time of ATI was resumed at confirmed viral rebound (CVR, defined as two consecutive HIV-RNA >50 copies/mL). Raw data of clinical data of all described patients are reported in table I of the manuscript. Collection of sera and analysis of both binding antibodies (BAbs) and neutralizing antibodies (NAbs) was performed at three different time points: ATI, CVR and time of viral re-suppression after antiretroviral treatment (ART) resumption. IgG subclasses (IgG1, IgG2, IgG3 and IgG4) from the 4 patients with highest levels of neutralization were found to block viral infection (raw data are reported here in fig 2 Fig3 IgG HIV). All subjects had CVR after ATI at a median time of 21 days (14-56). After ART resumption, all the enrolled subjects achieved HIV-RNA<50 copies/mL in 42 days (21-98) (as shown in fig 1 of the manuscript). We observed a strong increase of either BAbs and NAbs titers from ATI to viral re-suppression in one patient, who showed the longest period of virus undetectability during ATI. In this patient, BAbs and NAbs specifically belonged to both IgG1 and IgG4 subclasses, directed to env antigen. Raw data (fig4 HIV) here reported reports the characterization of antibodies in this patients. Further details are shown in fig 4 of the manuscript.