Asymptomatic anorectal Chlamydia trachomatis and Neisseria gonorrhoeae infections are associated with systemic CD8+ T-cell activation

AIDS. 2017 Sep 24;31(15):2069-2076. doi: 10.1097/QAD.0000000000001580.


Background: Oral preexposure prophylaxis (PrEP) has been established as a pivotal strategy in HIV prevention. However, bacterial sexually transmitted infections (STIs), such as Chlamydia trachomatis and Neisseria gonorrhoeae, are also highly prevalent. Although the presence of STI-related mucosal lesions is a known risk factor for HIV acquisition, the potential increase in risk associated with asymptomatic STIs is not completely understood. Recent data demonstrated higher T-cell activation is a risk factor for sexually acquired HIV-1 infection. We examined the effect of asymptomatic C. trachomatis and N. gonorrhoeae anorectal infection on systemic immune activation, potentially increasing the risk of HIV acquisition.

Methods: We analyzed samples from participants of PrEP Brasil, a demonstration study of daily oral emtricitabine/tenofovir disoproxil fumarate HIV PrEP among healthy MSM, for T-cell activation by flow cytometry. We included 34 asymptomatic participants with anorectal swab for C. trachomatis and/or N. gonorrhoeae infection, whereas negative for other STIs, and 35 controls.

Results: We found a higher frequency of human leukocyte antigen DRCD38 CD8 T cells (1.5 vs. 0.9%, P < 0.005) and with memory phenotype in the group with asymptomatic C. trachomatis and/or N. gonorrhoeae infection. Exhaustion and senescence markers were also significant higher in this group. No difference was observed in the soluble CD14 levels.

Conclusion: Our findings suggest asymptomatic anorectal C. trachomatis and/or N. gonorrhoeae increase systemic immune activation, potentially increasing the risk of HIV acquisition. Regular screening and treatment of asymptomatic STIs should be explored as adjuvant tools for HIV prevention.

MeSH terms

  • ADP-ribosyl Cyclase 1 / analysis
  • Adult
  • Asymptomatic Diseases
  • CD8 Antigens / analysis
  • CD8-Positive T-Lymphocytes / chemistry
  • CD8-Positive T-Lymphocytes / immunology*
  • Chlamydia Infections / pathology*
  • Chlamydia trachomatis / isolation & purification
  • Cross-Sectional Studies
  • Flow Cytometry
  • Gonorrhea / pathology*
  • HLA-DR Antigens / analysis
  • Humans
  • Lymphocyte Activation*
  • Male
  • Membrane Glycoproteins / analysis
  • Neisseria gonorrhoeae / isolation & purification
  • Rectal Diseases / pathology*
  • Young Adult


  • CD8 Antigens
  • HLA-DR Antigens
  • Membrane Glycoproteins
  • CD38 protein, human
  • ADP-ribosyl Cyclase 1