Brief Report: HIV-1 Seroconversion Is Not Associated With Prolonged Rectal Mucosal Inflammation : JAIDS Journal of Acquired Immune Deficiency Syndromes

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Brief Report: HIV-1 Seroconversion Is Not Associated With Prolonged Rectal Mucosal Inflammation

Blair, Cheríe S. MD, MPHa; Lake, Jordan E. MD, MScb; Passaro, Ryan C. MD, MPHc; Chavez-Gomez, Susan BAd; Segura, Eddy R. MD, MPHa,e; Elliott, Julie MSa; Fulcher, Jennifer A. MD, PhDa; Shoptaw, Steven PhDf; Cabello, Robinson MDd; Clark, Jesse L. MD, MSca

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JAIDS Journal of Acquired Immune Deficiency Syndromes 86(5):p e134-e138, April 15, 2021. | DOI: 10.1097/QAI.0000000000002601

Abstract

INTRODUCTION

Men who have sex with men (MSM) and transgender women (TW) are disproportionately affected by the HIV and sexually transmitted infection (STI) epidemics.1 Rectal Neisseria gonorrhoeae and/or Chlamydia trachomatis (GC/CT) are of particular public health importance as they are independently associated with HIV seroconversion, a relationship which is driven by rectal inflammation caused by rectal GC/CT infection.2 Mucosal inflammation increases the risk for HIV seroconversion through decreased mucosal barrier integrity and recruitment of HIV-susceptible cells, such as T lymphocytes and macrophages.3,4 In addition, mucosal inflammation caused by STIs has been associated with increased viral shedding among individuals with HIV, independent of systemic HIV viral load.5 Regarding the rectal compartment, these risks are potentiated by abundant levels of activated CD4+ T lymphocytes, key target cells for HIV infection, that exist in the rectal mucosa and contribute to ongoing HIV transmission among MSM through condomless receptive anal intercourse (RAI).4

Although rectal mucosal inflammation is associated with an increased risk of HIV transmission, the effects of HIV infection on mucosal inflammation remain largely unexplored. Given the surge in HIV replication associated with acute HIV infection, rectal inflammation in the setting of HIV seroconversion may represent an important driver of HIV transmission among serodiscordant partners. Cross-sectional studies have determined that chronic HIV infection does not result in elevated mucosal cytokine levels, regardless of HIV systemic viral load or antiretroviral therapy use.6 However, the impact of acute HIV seroconversion on rectal cytokine levels remains unknown. To address this gap, we performed a secondary analysis of MSM and TW who participated in an intervention using rectal STI screening and treatment for HIV prevention in Lima, Peru, to evaluate the association of HIV seroconversion on cytokine levels in the rectal mucosa.

METHODS

Participants and Recruitment

We conducted a secondary analysis of MSM and TW who participated in an intervention using rectal STI screening and treatment for HIV prevention in Lima, Peru. Participants were recruited from community venues by peer recruiters at Via Libre, a community-based organization that provides integrated sexual health services in Lima, Peru, from July to December 2017. Enrollment was limited to individuals who (1) were ≥18 years old, (2) were assigned male sex at birth, (3) reported condomless RAI with an HIV-infected or unknown serostatus partner in the previous 3 months, and (4) were HIV-uninfected according to a fourth generation rapid test. At the screening visit, participants underwent testing for rectal GC/CT, syphilis, and HIV by fourth generation rapid testing. Of the 469 HIV-uninfected participants who underwent screening, 101 had rectal GC/CT, from whom 50 GC/CT-positive cases were randomly selected, along with 52 GC/CT-negative controls who were matched according to the age and number of RAI partners during the last 30 days. Participants were matched for RAI as condomless RAI has been demonstrated to cause an increase in proinflammatory cytokines within the rectal mucosa for up to 24 hours.7 Participants completed behavioral surveys, HIV/STI screening, and collection of rectal samples every 3 months (baseline, 3 months, and 6 months).

Study Procedures

All participants completed a computer-assisted self-interview at each visit, which included age, number of RAI partners in the last month, and condom use. At baseline, 3 months, and 6 months, participants were screened for rectal GC/CT, syphilis, and HIV and underwent physical examination for signs of symptomatic urethritis or proctitis. Rectal swabs were collected and tested for GC/CT infection with nucleic acid amplification testing using the Gen-Probe Aptima II assay (Hologic, San Diego, CA). Blood was collected to test for syphilis by rapid plasma reagin (RPR) assay (RPRnosticon, Biomérieux, Marcy l'Etoile, France) with Treponema pallidum particle agglutination assay confirmation (Serodia Treponema pallidum particle agglutination assay, Fujirebio, Malvern, PA). For the purpose of this analysis, RPR titers ≥16 were considered consistent with current syphilis infection and included in our findings. HIV screening was conducted on whole blood with rapid fourth generation testing (Alere Determine, Abbott, Chicago, IL). Participants with clinically symptomatic urethritis, proctitis, or with positive GC/CT nucleic acid amplification testing were treated with ceftriaxone 250 mg intramuscular injection and azithromycin 1 g orally, according to the Centers for Disease Control (CDC) guidelines.8 All participants were provided with testing results within 2 weeks of result. Participants with syphilis received treatment according to the stage of their infection after a physician review of previous RPR titers and treatment history. Participants were compensated 15 Nuevos soles (US $5) for screening, 25 N. soles ($8) at enrollment, 35 N. soles ($12) for 3-month follow-up, and 45 N. soles ($15) for 6-month follow-up.

Rectal Sponge Collection and Cytokine Quantification

Rectal samples were collected at baseline, 3 months, and 6 months for cytokine analysis. Rectal secretions were collected using sterile polyvinyl acetate sponges (Merocel, Beaver Visitec, Waltham, MA) introduced into the rectum using anoscopy and held against the rectal mucosa under direct visualization for 120 seconds.9,10 Sponges were stored at −80°C until processing. For processing, sponges were thawed on ice, and sponge tips were transferred to a 2-mL Spin-X column (Corning, Corning, NY) from which the acetate membrane was removed to prevent protein binding. Rectal secretions were eluted twice with 250 μL of cold elution buffer [PBS containing 0.25% bovine serum albumin, 1% Igepal (Sigma Chemicals), and protease inhibitor cocktail (Sigma Chemicals)] by centrifugation (10,000 rpm for 30 minutes at 4°C). Interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor (TNF)-α were then measured using a custom Milliplex High-Sensitivity multiplex panel (MilliporeSigma, Burlington, MA) according to manufacturer's instructions. Samples were run in duplicate and repeated if coefficient of variation was (%CV) >25%.

Consent/Permissions

Written informed consent was obtained from all participants before enrollment. The study protocol was reviewed and approved by the Institutional Review Boards of the University of California, Los Angeles, and Asociación Civil Via Libre. This study was registered on clinicaltrials.gov (NCT03010020).

Data Analysis

Bivariate analyses, with Fisher exact and Kruskal–Wallis tests when appropriate, were used to compare participant characteristics and sexual behaviors between individuals diagnosed with HIV during follow-up and those who remained HIV-negative. Wilcoxon rank-sum tests compared inflammatory cytokine concentrations between persons diagnosed with HIV during follow-up and those who remained HIV-negative. All analyses were conducted using Stata 15.0 (StataCorp, College Town, TX). By completion of the study, 6 HIV-negative participants and 1 participant who experienced HIV seroconversion were lost to follow-up. Less than 5% of data were missing for any single variable.

RESULTS

The median age of participants was 24 years ([interquartile range (IQR) 21–29]. The median number of last month RAI partners was 4 (IQR 2–7; range 0–20). At 3 months, 6 participants experienced HIV seroconversion, followed by an additional 2 participants at 6 months, resulting in a total of 8 individuals who experienced HIV seroconversion by study completion. No differences were observed in baseline age or number of last month RAI partners between participants who experienced HIV seroconversion compared with those who remained HIV-negative (Table 1). At baseline, 75% (6/8) of participants who experienced seroconversion had rectal GC/CT infection, compared with 43.6% (41/94) of HIV-negative participants (P = 0.14). Among participants who experienced HIV seroconversion, one participant (12.5%) had recurrent GC/CT at 3 months. Among HIV-negative participants, 15.7% (14/89) and 10.2% (9/88) had recurrent GC/CT at 3 and 6 months, respectively. The median number of RAI partners in the month before HIV diagnosis was 2 for both those with HIV seroconversion (IQR 0.5–3; range 0–4) and participants who remained HIV-negative (IQR 1–3; range 0–10; P = 0.79). In the month before HIV diagnosis, the median number of condomless RAI partners was 1 for both HIV seroconverters (IQR 0–1.5; range 0–4) and those who remained HIV-negative (IQR 0–2; range 0–10; P = 0.93).

TABLE 1. - Participant Characteristics and Sexual Risk Behaviors Among Men Who Have Sex With Men and Transgender Women Stratified by HIV-1 Seroconversion; Lima, Peru 2018–2019 (N = 102)
HIV-1 Seroconverters HIV-1 Uninfected Controls P*
n % n %
Baseline n = 8 n = 94
 Age 25 (22–31) 24 (21–29) 0.62
 Gender
  Cisgender male 6 75 76 80.9 0.69
  Transgender female 2 25 18 19.2
 Rectal GC/CT
  Negative 2 25 53 56.4 0.14
  Positive 6 75 41 43.6
 Syphilis
  Negative 7 87.5 91 96.8 0.28
  Positive 1 12.5 3 3.2
 Sexual partners last mo 4.5 (2.5–5.5) 6 (2.5–10) 0.39
 RAI partners last mo 4.5 (2.5–8) 4 (2–7) 0.71
 CRAI partners last mo 2.5 (1–4) 3 (1–4) 0.93
3-month follow-up n = 8 n = 89
 Rectal GC/CT
  Negative 7 87.5 75 84.3 1.00
  Positive 1 12.5 14 15.7
 Sexual partners 3 (0.5–3.5) 2 (1–4) 0.69
 RAI partners last mo 2 (0.5–3) 2 (1–3) 0.79
 CRAI partners last mo 0.5 (0–1.5) 1 (0–2) 0.71
6-month follow-up n = 7 n = 88
 Rectal GC/CT
  Negative 7 100 79 89.8 0.49
  Positive 0 0 9 10.2
 Sexual partners last mo 3 (0–4) 2 (1–5) 0.94
 RAI partners last mo 3 (0–4) 1 (0.5–3) 0.72
 CRAI partners last mo 0 (0–1) 0 (0–1) 0.29
Month before seroconversion n = 8 n = 88
 Sexual partners 3 (0.5–3.5) 2 (1–4) 0.69
 RAI partners 2 (0.5–3) 2 (1–3) 0.79
 CRAI partners 1 (0–1.5) 1 (0–2) 0.93
*Calculated using Fisher exact or Kruskal–Wallis tests.
Median (interquartile range).
CRAI, condomless receptive anal intercourse.

At baseline, no differences were observed in median rectal mucosal cytokine concentrations for all cytokines measured (IL-1β, IL-6, IL-8, and TNF-α) between participants who experienced HIV seroconversion and those who remained HIV-negative (Fig. 1). At 3 months, where most participants (6/8) were diagnosed with HIV infection, there were no differences in median rectal mucosal cytokines (IL-1β, IL-6, IL-8, and TNF-α) between those who seroconverted and participants who remained HIV-negative. No differences in median rectal mucosal cytokines were observed between HIV seroconverters and those who remained HIV-negative at 6 months. The median and mean rectal mucosal cytokine concentrations are given in Table 1, Supplemental Digital Content, https://links.lww.com/QAI/B584. Rectal mucosal cytokine levels for participants who experienced HIV seroconversion are given in Table 2, Supplemental Digital Content, https://links.lww.com/QAI/B584.

F1
FIGURE 1.:
Median rectal mucosal cytokine levels of MSM who experienced HIV-1 seroconversion compared with MSM and TW who remained HIV-negative; Lima, Peru 2018–2019. Box plots display the 25th percentile, median, and 75th percentile of values. Lower whiskers represent the minimum value of data within 1.5 times of the interquartile range (IQR) below the 25th percentile. Upper whiskers represent the maximum value of data within 1.5 times the IQR above the 75th percentile. P-values calculated using Wilcoxon Rank-Sum tests. IL, interleukin; TNF, tumor necrosis factor.

DISCUSSION

This is the first study to evaluate inflammatory cytokine levels in the rectal mucosa after HIV seroconversion. In this analysis of MSM and TW who participated in an intervention using rectal STI screening and treatment for HIV prevention in Lima, Peru, individuals who experienced HIV seroconversion did not have any differences in rectal mucosal cytokine levels compared with participants who remained HIV seronegative. Despite a surge in viral replication during acute infection, our findings suggest that HIV-1 acquisition does not seem to result in a prolonged inflammatory process. These results are in stark contrast with the dramatic increase in mucosal inflammation that is observed with GC/CT infection.4,11

Our findings are initially surprising, particularly as acute HIV-1 infection results in a surge in viral replication, immune activation, and destruction of gut-associated lymphoid tissue CD4+ T cells.12,13 HIV infection has also been associated with increased mRNA expression of inflammatory cytokines, such as IL-4, IL-6, IL-10, and TNF-α, in colonic mucosa regardless of antiretroviral therapy use or viral load.14,15 However, at least one other study has compared inflammatory cytokine levels in the rectal mucosa during HIV infection and found that chronic HIV infection is not associated with elevated rectal mucosal cytokine levels,6 congruent with our findings. The discrepancy observed between cytokine mRNA expression documented in previous studies and cytokine levels measured in the rectal mucosa may be related to anatomic location of sampling, different regulatory mechanisms between mRNA expression and protein, and host factors contributing to localized inflammation. Better understanding of the mechanisms leading to and regulating mucosal inflammation in HIV is an important area for future study.

Our study has several strengths. This is the first longitudinal study evaluating the effects of HIV seroconversion on rectal inflammation among a group of MSM and TW in a study with high rates of retention. However, the study does have some limitations. Given the small sample size of participants who experienced HIV seroconversion (n = 8), our analysis may not be adequately powered to detect small differences in cytokine concentrations, particularly given substantial variation in cytokine levels in both groups. In addition, HIV viral load among those who experienced HIV seroconversion was not known because these data were not collected as part of this study. However, it is likely that HIV viremia at the time of diagnosis was high because all participants who experienced HIV seroconversion had received their diagnosis through this study and were not receiving antiretroviral therapy. Most importantly, the timing of rectal sampling to acute HIV infection is unknown, particularly as HIV was diagnosed with an antibody test and not PCR. Because study visits occurred every 3 months, it is probable that HIV infection and mucosal sampling may be separated by several weeks to months. For this reason, we can conclude that HIV seroconversion does not associate with prolonged rectal inflammation but may still result in inflammation limited to the more acute period. As rectal inflammation is associated with an increased risk of HIV/STI transmission, future studies evaluating the impact of acute HIV-1 seroconversion on rectal mucosal cytokine levels are warranted. The absence of rectal mucosal inflammation associated with HIV seroconversion, if confirmed in subsequent studies, may have important implications for research on HIV prevention and transmission.

ACKNOWLEDGMENTS

The authors thank the participants and their families. In addition, the authors acknowledge Williams Gonzales, the study teams, and clinical research staff at the study sites.

REFERENCES

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Keywords:

HIV seroconversion; rectal inflammation; rectal cytokines; MSM; Latin America; Peru

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