ABSTRACT
Background: A significant portion of individuals experience persistent symptoms months after SARS-CoV-2 infection, broadly referred to as Long COVID (LC). Although the frequencies of subsets of SARS-CoV-2-specific T cells have been shown to differ in individuals with LC relative to those with complete recovery, a deep dive into phenotypic and functional features of total and SARSCoV- 2-specific T cells from individuals with LC has yet to be performed. Method(s): Here, we used CyTOF to characterize the phenotypes and effector functions of T cells from LIINC cohort. The median age was 46, the cohort was 55.8% female, and 9/43 had been hospitalized. Participants were reported a median of 7 LC symptoms at 8 months. SARS-CoV-2-specific total antibody levels were also measured in concurrent sera. Manual gating was used to define T cell subsets, SPICE analyses for polyfunctionality, T cell clustering for phenotypic features, and linear regression for correlation. Permutation tests, Student's t tests, and Welch's t test were used for statistical analysis. Result(s): SARS-CoV-2 total antibody responses were elevated in the LC group (p=0.043), and correlated with frequencies of SARS-CoV-2-specific T cells in those without LC (r=0.776, p< 0.001) but not those with LC. While the frequencies of total SARS-CoV-2-specific CD4+ and CD8+ T cells were similar between individuals with and without LC, those from individuals without LC tended to be more polyfunctional (co-expressing IFNgamma, TNFalpha, IL2, and/or MIP1beta). CD4+ T cells from individuals with LC harbored higher frequencies of Tcm (p=0.003), Tfh (p=0.037), and Treg subsets (p=0.0412), and preferentially expressed a variety of tissue homing receptors including CXCR4 and CXCR5 (p=0.037). SARS-CoV-2-specific CD4+ T cells producing IL6, albeit rare, were observed exclusively among those with LC (p=0.016). In addition, participants with LC harbored significantly higher frequencies of SARS-CoV-2-specific CD8+ T cells co-expressing exhaustion markers PD1 and CTLA4 (p=0.018). Conclusion(s): Long COVID is characterized by global phenotypic differences in the CD4+ T cell compartment in ways suggesting preferential migration of these cells to inflamed mucosal tissues. Individuals with LC also harbor higher numbers of exhausted SARS-CoV-2-specific CD8+ T cells, potentially implicating viral persistence. Finally, our data additionally suggest that individuals with LC may uniquely exhibit an uncoordinated T cell and antibody response during COVID-19 convalescence.
ABSTRACT
Background: There is mounting evidence regarding the frequency and spectrum of post-acute sequelae of SARS-CoV-2 infection (PASC), but a search for causes has been elusive. Recently, a plasma-based assay for SARS-CoV-2 antigen has been developed, which in initial use revealed that a high fraction of severely affected patients with PASC had circulating antigen. It is unknown whether detectable SARS-CoV-2 antigen is specific for PASC or how the assay performs in a broader clinical spectrum of patients with PASC. Method(s): We evaluated a cohort of patients with RNA-confirmed SARS-CoV-2 infection enrolled >=3 weeks following initial symptoms. Participants, both with and without PASC at enrollment, were identified via facility- and communitybased advertising and examined every 4 months. An interviewer-administered questionnaire ascertained presence of 30 different symptoms (new or worse compared to pre-COVID) in the prior 2 days at each exam. Using the single molecule array (Simoa) assay, we measured spike, S1, and nucleocapsid SARSCoV- 2 antigens in plasma collected at time of symptom assessment. Result(s): We examined 172 participants (50% men, 46% non-white, median age 46 years) who contributed 667 timepoints from 0.7 to 15.4 months following infection, at which 66% featured report of >=1 symptom. Sixty-one of 667 timepoints (9.1%) representing 24% of persons had >=1 detectable SARSCoV- 2 antigen. Among the 437 timepoints at which >=1 symptom was present, 9.8% had >=1 detectable antigen;this compares to 7.8% of timepoints at which symptoms were absent. In comparison to those without symptoms, individuals with several specific symptom complexes (gastrointestinal, musculoskeletal, and central neurologic) more commonly had detectable antigen (Figure). Hospitalization during acute COVID-19 was strongly related to antigen detection. Conclusion(s): Among a diverse group of SARS-CoV-2-infected persons in the post-acute phase of infection, SARS-CoV-2 antigen is detectable in plasma in both those with and without symptoms but more commonly in those with gastrointestinal, musculoskeletal, and central neurologic complaints. The findings indicate that antigen persists in at least some persons and suggest (but do not prove) that antigen is causally related to symptoms. That antigen is found in only a fraction of those with PASC indicates either that not all symptoms are driven by antigen, current plasma antigen detection is insensitive relative to tissue, or nominal PASC symptoms are sometimes unrelated to SARS-CoV-2. (Figure Presented).
ABSTRACT
Background: Reduced exercise capacity occurs as a post-acute sequela of COVID-19 ("PASC" or "Long COVID"). Cardiopulmonary exercise testing (CPET) is the gold standard for measuring exercise capacity and identifying reasons for exercise limitations. Only one prior study used CPET to examine exercise limitations among people living with HIV (PLWH). Extending our prior findings in PASC, we hypothesized that PLWH would have a greater reduction in exercise capacity after SARS-CoV-2 co-infection due to chronotropic incompetence (inability to increase heart rate). Method(s): We performed CPET within a COVID recovery cohort that included PLWH (NCT04362150). We evaluated associations of HIV and prior SARS-CoV- 2 infection with or without PASC with: (1) exercise capacity (peak oxygen consumption, VO2) and (2) adjusted heart rate reserve (AHRR, marker of chronotropic incompetence) using linear regression with adjustment for age, sex, and body mass index. Result(s): We included 83 participants (median age 54, 35% female, 10% hospitalized, 37 (45%) PLWH) who underwent CPET at 16 months (IQR 14-17) after SARS-CoV-2 infection. Among PLWH (median duration living with diagnosed HIV 21 years (IQR 15-28), all virally suppressed on antiretroviral therapy), 14 (39%) had not had SARS-CoV-2 infection, 12 (32%) had prior SARSCoV- 2 infection without PASC, and 11 (30%) had PASC (Long COVID symptoms at CPET). Median CD4 count was 608 (370-736) and CD4/CD8 ratio 0.92 (0.56-1.27). Peak VO2 was reduced among PLWH compared to individuals without HIV with an achieved exercise capacity only 80% vs 99% (p=0.005, Fig.), a difference in peak VO2 of 5.5 ml/kg/min (95%CI 2.7-8.2, p< 0.001). Exercise capacity did not vary by SARS-CoV-2 infection among PLWH (p=0.48 for uninfected vs infected;p=0.25 for uninfected vs no PASC;p=0.32 no PASC vs PASC). Chronotropic incompetence was present in 38% of PLWH vs 11% without HIV (p=0.002), and AHRR (normal >80%) was significantly reduced among PLWH vs individuals without HIV (60% vs 83%, p< 0.0001, Fig.). Heart rate response varied by SARSCoV- 2 status among those with HIV: namely, 3/14 (21%) without SARS-CoV-2, 4/12 (25%) with SARS-CoV-2 without PASC, and 7/11 (64%) with PASC (p=0.04 PASC vs no PASC). Among PLWH, CD4 count, CD4/CD8 ratio, and hsCRP were not associated with peak VO2 or AHRR. Conclusion(s): Exercise capacity is reduced among PLWH, with no differences by SARS-CoV-2 infection or PASC. Chronotropic incompetence may be a mechanism of reduced exercise capacity among PLWH. (Figure Presented).
ABSTRACT
Background: Antigen-driven CD4+ T cell proliferation is a proposed mechanism of HIV-1 reservoir persistence. We previously reported that SARSCoV- 2 infection leads to increased detectable low-level HIV-1 plasm RNA blips months after COVID-19, but the impact of SARS-CoV-2-mediated T cell activation on expansion of HIV-1 reservoirs is not known. We sought to identify if SARSCoV- 2 infection leads to expansion of preferentially HIV-infected CD4+ T cells in people with HIV (PWH) on ART. Method(s): Five PWH with samples collected prior to and approximately two months after SARS-CoV-2 infection were identified. We performed a surface activation induced marker (AIM) assay using a CD4-optimized overlapping SARS-CoV-2 peptide pool to measure OX40/CD137 expression following peptide stimulation and sorted CD4+ T cells based on surface marker expression. ddPCR quantification of genomic HIV-1 DNA was performed on sorted subsets. Result(s): We observed an increase in the frequency of SARS-CoV-2 AIM+ non-naive CD4+ T cells following COVID-19 in samples from 4 of 5 participants (mean AIM+ % 0.13 pre- vs 0.31 post). A large percentage of non-naive AIM+ CD4+ T cells expressed PD1 compared with total non-naive cells before (76% vs 36%) and after (65% vs 19%) COVID-19;PD1 expression was lower following SARS-CoV-2 in both AIM+ and AIM- CD4+ T cell subsets (although very few cells were AIM+ prior to COVID-19). HIV-1 DNA levels in non-naive AIM- CD4+ T cells prior to COVID-19 unexpectedly decreased following infection (mean 3,522 to 766 copies/106 cells). The numbers of AIM+ cells obtained by cell sorting were overall low ( 3,863 mean) and only one participant had detectable DNA in post-COVID AIM+ CD4+ T cells. However, a large majority of this participant's post-COVID AIM+ cells harbored HIV-1 DNA (0.89 copies per cell) whereas HIV DNA in their AIM- cells decreased from 8,387 to not detected following SARSCoV- 2 infection. No HIV-1 DNA was detected in the small number of AIM+ cells obtained prior to COVID-19 in this participant. Conclusion(s): COVID-19 in PWH led to a modest SARS-CoV-2-specific CD4+ cell response approximately two months following acute presentation. One participant may have preferentially expanded HIV-1-infected, SARS-CoV-2- specific CD4+ T cells following COVID-19 but studies involving larger numbers of participants and larger numbers of cells will be needed to fully understand the impact of SARS-CoV-2 on clonal expansion and HIV persistence.