Thursday, March 19, 2015

An Update on the "Mississippi Child"

In 2013, an article published in the esteemed New England Journal of Medicine (NEJM) offered a glimmer of hope for an HIV cure.  Because the HIV virus is responsible for considerable morbidity and mortality across the world, HIV treatment development has been the focus of fervid research efforts.  There have been many successes in treatment innovations and improvements over the years but only in one person--known as the "Berlin patient"--has the virus ever been fully eradicated once infection has been established in a human body.  In 2013, Persaud et. al. revealed that a newborn who came to be known as the "Mississippi Child" appeared to have been cured of HIV after receiving antiretroviral therapy between the ages of 30 hours and 18 months.  This tentative conclusion was made after the virus had disappeared from the child's blood for over 12 months, during which time the immune system did not appear to be actively fighting a retrovirus.

Because HIV, like other human viruses, is an obligate intracellular parasite--it must co-opt machinery from inside host cells in order to replicate--the full population of viruses inside an infected individual can never be seen through blood sampling alone.  In a Letter to Editor also published in the NEJM, the research team behind the 2013 publication explained that the "Mississipi child" case no longer represents a putative 'curing' of HIV infection but instead represents a strong lesson in the power of the HIV virus to hide inside humans cells beyond the detection capacities of serological testing for extended periods of time, underscoring the importance of targeting viral reservoir cells in HIV treatment.

Because the Mississippi child appeared to have been cured of HIV, antiretroviral medication administration was stopped.  All assessments boded well for the first 21.9 months after the discontinuation of antiretroviral therapy, during which the infection remained undetectable.  However, at 46.4 months old the child experienced a substantial viral resurgence.  During the period of quiet before this relapse, the virus was not absent but instead simply quiescent.  Many viruses use strategies of slow, insidious infection development in hosts in order to maintain themselves in a human population.  By contrast, viruses that too aggressively drag their hosts into devastating illness can burn out much more quickly in human populations.

Read the full Letter to the Editor here:  http://www.nejm.org/doi/full/10.1056/NEJMc1413931

--Laurie


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