HIV superinfection

HIV superinfection (also called HIV reinfection) is a condition in which a person with established human immunodeficiency virus infection acquires a second strain of the virus.^[1] The HIV superinfection strain (a recombinant strain) appears when a person becomes infected by two different strains, allowing DNA to fuse and create a new one. The second strain co-exists with the first and may cause more rapid disease progression or carry resistance to certain HIV medication.

People with HIV risk superinfection by the same actions that would place a non-infected person at risk of acquiring HIV. These include sharing needles and forgoing condoms with HIV-positive sexual partners. For many years superinfection was thought to occur mainly in high-risk populations. Research from Uganda published in 2012 indicates that HIV superinfection among HIV-infected individuals within a general population remains unknown.^[2] Further research from The Journal of Infectious Diseases indicates that there have been 16 documented cases of superinfection since 2002.^[3]

Immunology of HIV superinfection

It is unknown what aspects of the natural immune response to HIV may protect someone from superinfection, but it has been shown that cytotoxic lymphocyte responses do not seem to be protective.^[4] In addition, it has been demonstrated that superinfection can occur in individuals that demonstrate a robust anti-HIV antibody response. The anti-HIV antibody response broadens and strengthens in individuals post-superinfection.^[5] Taken with the finding that super-infection is common and occurs within and between HIV subtypes it has been suggested that the immune response elicited by primary infection may confer limited protection and raises concerns that HIV-vaccine strategies designed to replicate the natural anti-HIV immune response may have limited effectiveness in preventing new infections. However at the same time, HIV-infected individuals at high-risk for super-infection who do not become superinfected may also provide a very interesting avenue for new vaccine research.

HIV co-infection offset

A study in the New England Journal of Medicine titled "Inhibition of HIV-1 Disease Progression by Contemporaneous HIV-2 Infection" revealed that people who are HIV-positive with the two major subtypes have a slower progression towards AIDS than people with only HIV-1 or HIV-2. This challenges the notion of superinfection by illustrating that contemporaneous infection can offset itself.^[6]

References

1. Smith DM, Richman DD, Little SJ (August 2005). "HIV superinfection". J. Infect. Dis. 192 (3): 438–44. doi:10.1086/431682. PMID 15995957. Retrieved 2008-06-20.
2. Redd, Andrew; et al. (June 2012). "The Rates of HIV Superinfection and Primary HIV Incidence in a General Population in Rakai, Uganda". Journal of Infectious Disease 206 (2): 267–274. doi:10.1093/infdis/jis325. PMID 22675216.
3. Smith, Davey M.; Richman, Douglas D.; Little, Susan J. (2005-08-01). "HIV Superinfection". Journal of Infectious Diseases 192 (3): 438–444. doi:10.1086/431682. ISSN 0022-1899. PMID 15995957.
4. Blish, Catherine; et al. (2011). "Cellular immune responses and susceptibility to HIV-1 superinfection: a case-control study". AIDS 26 (5): 643–6. doi:10.1097/QAD.0b013e3283509a0b. PMID 22210637.
5. Cortez, Valerie; et al. (2012). "HIV-1 Superinfection in Women Broadens and Strengthens the Neutralizing Antibody Response". PLOS Pathogens 8 (3): e1002611. doi:10.1371/journal.ppat.1002611. PMID 22479183.
6. Esbjörnsson, Joakim; et al. (2012). "Inhibition of HIV-1 Disease Progression by Contemporaneous HIV-2 Infection". New England J. Med. 367 (3): 224–232. doi:10.1056/NEJMoa1113244. PMID 22808957.