title: Sexual activity modulates shifts in TH1/TH2 cytokine profile across the menstrual cycle: an observational study.
abstract: OBJECTIVE
  To investigate if sexual activity moderated menstrual cycle-related shifts in cytokines associated with T-helper type 1 (TH1) cells (e.g., interferon [IFN] γ) and T-helper type 2 (TH2) cells (e.g., interleukin [IL] 4). Immune activity shifts across the menstrual cycle, with higher follicular-phase TH1-cell activity but higher luteal-phase TH2-cell activity. Little is known about how social behaviors alter TH1-TH2 ratios, despite evidence that psychosocial factors can influence immunity. Of particular interest is how sexual activity influences immune responses that may support conception, such as the TH1-TH2 balance.
  
  
  METHODS
  Participants provided saliva samples at four time points (menstrual, follicular, ovulatory, and luteal phases), which were assayed by means of ELISA.
  
  
  METHODS
  Academic laboratory.
  
  
  METHODS
  Thirty healthy premenopausal women (16 sexually abstinent, 14 sexually active) not taking hormonal or immunoactive medications.
  
  
  METHODS
  None.
  
  
  METHODS
  Salivary E2, P, IFN-γ, and IL-4.
  
  
  RESULTS
  Sexually active, but not abstinent, women were significantly more likely to express TH2-like cytokine ratios (IFN-γ < IL-4) in the luteal phase than in other phases. Similarly, sexually active women had significantly higher P, and higher P-E2 ratios, in the luteal phase than did abstinent women. The P-E2 ratio mediated menstrual variations in cytokine ratios in sexually active women.
  
  
  CONCLUSIONS
  These results support the hypothesis that shifts in immune response across the menstrual cycle may reflect tradeoffs between reproduction and immunity. These findings point to the need for further research on the interaction between sexual behavior, the menstrual cycle, and immune response.
authors.affiliation: Center for Integrative Study for Animal Behavior, Indiana University, Bloomington, Indiana; Kinsey Institute for Research on Sex, Gender, and Reproduction, Indiana University, Bloomington, Indiana. Electronic address: lorenzt@indiana.edu.
authors.forename: Tierney K
authors.initials: TK
authors.lastname: Lorenz
authors.affiliation: Center for Integrative Study for Animal Behavior, Indiana University, Bloomington, Indiana; Kinsey Institute for Research on Sex, Gender, and Reproduction, Indiana University, Bloomington, Indiana; Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana.
authors.forename: Julia R
authors.initials: JR
authors.lastname: Heiman
authors.affiliation: Center for Integrative Study for Animal Behavior, Indiana University, Bloomington, Indiana; Department of Biology, Indiana University, Bloomington, Indiana.
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Demas
mesh_terms: D000293:Adolescent; D000328:Adult; D016207:Cytokines / Q000276:immunology* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D004958:Estradiol / Q000378:metabolism; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology / Q000378:metabolism; D015847:Interleukin-4 / Q000276:immunology / Q000378:metabolism; D008597:Menstrual Cycle / Q000276:immunology* / Q000378:metabolism; D011374:Progesterone / Q000378:metabolism; D012463:Saliva / Q000276:immunology / Q000378:metabolism; D012746:Sexual Abstinence; D012725:Sexual Behavior; D018417:Th1 Cells / Q000276:immunology* / Q000378:metabolism; D058408:Th1-Th2 Balance; D018418:Th2 Cells / Q000276:immunology* / Q000378:metabolism; D013997:Time Factors; D055815:Young Adult
chemical_list: D016207:Cytokines; C573415:IFNG protein, human; C508598:IL4 protein, human; D015847:Interleukin-4; D011374:Progesterone; D004958:Estradiol; D007371:Interferon-gamma
keywords: Immunity; T(H)1-T(H)2; cytokine; menstrual cycle; sex differences