Saliva

Published: 07 April 2009

A number of studies have shown that whole saliva protects susceptible cells against HIV infection. Several inhibitory components in oral secretions have been described:1

  • HIV-specific antibodies: neutralise and inactivate virus.
  • Complement: in conjunction with fibronectin, binds to and sediments virus.
  • Cystatins: perform general antimicrobial activity; inhibit cysteine proteases.
  • Defensins: perform general antimicrobial activity; block virus entry.
  • Lactoferrin: binds iron to inhibit bacterial growth.
  • Lactoperoxidase: inactivates virus through hypothiocyanite production.
  • Lysozyme: lyses bacteria.
  • Mucins: entrap and aggregate viral particles.
  • Secretory leucocyte protease inhibitor (SLPI): prevents virus entry into host cells.
  • Thrombospondin: aggregates virus; blocks virus-CD4 interactions during virus entry.

Nonetheless, although in the early years of the epidemic, HIV was rarely isolated in saliva, or was only isolated in small quantities,2 the development of more sensitive polymerase chain reaction (PCR) methods has led to a greater frequency of detecting HIV RNA in saliva.1 

For example, one study found that saliva was detectable in 91% of people during primary infection and 82% of people in untreated, chronic infection. Viral loads were comparable to those in semen, and were correlated with those in blood plasma,3 although a French study found only a weak correlation with plasma.4

In another study, 42% of subjects had detectable HIV in saliva, and this was more common in people with periodontal disease, severe gingival inflammation or no combination therapy. Studies have reported individuals who have had higher viral loads in saliva than in blood.5 6

Dramatic reductions in the presence of HIV RNA in saliva have been reported after commencing combination therapy, either with an NNRTI3 or with a protease inhibitor.7

But although HIV is present in saliva, the components described above inhibit the ability of HIV to infect new cells. Unless there is visible blood in saliva, it is not considered a body fluid through which HIV can be transmitted.6

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References

  1. Shugars DC et al. The role of the oral environment in HIV-1 transmission. JADA 129:851-858, 1998
  2. Shine N et al. The anti-HIV-1 activity associated with saliva. J Dent Res 76:634-640, 1996
  3. Pilcher CD et al. HIV in body fluids during primary HIV infection : implications for pathogenesis, treatment and public health. AIDS 15:837-845, 2001
  4. Bourlet T et al. Compartmentalization of HIV-1 according to antiretroviral therapy: viral loads are correlated in blood and semen but poorly in blood and saliva. AIDS 15: 284-285, 2001
  5. Liuzzi G et al. Analysis of HIV-1 load in blood, semen and saliva: evidence for different viral compartments in a cross-sectional and longitudinal study. AIDS 10: F51-F56, 1996
  6. Shugars DC et al. HIV-1 RNA load in blood plasma, saliva and crevicular fluid. J Dent Res 77(Special Issue A):285, 1998
  7. Liuzzi G et al. Reduction of HIV-1 viral load in saliva by indinavir-containing antiretroviral regimen. AIDS 16:503-504, 2002
This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.
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This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member of your healthcare team for advice tailored to your situation.