Paleogenetics is the science that studies the past through the analysis of genetic material, giving valuable information about the evolution of living things, their habits as well as their diseases.
And what is the role of paleogenetics in the evolution of living things?
And what is the role of paleogenetics in such a recent disease as HIV infection?"
Approximately 10% of the European population carries a mutation that appears to offer protection against this infection: there is evidence that this mutation may have originated, as a result of an epidemic.
Researchers are still divided on whether this "protection" is due to the smallpox infection or the plague, but not on whether the CCR5-Δ32 mutation derives from either. The CCR5 protein is a membrane protein of white blood cells, which prevents the virus from entering the cell.
It is interesting how this mutation has a very different prevalence in Europe itself with peaks of 16% in Russia and Finland and a reduced 4% in Sardinia and 3% in the Turkish portion of the Cyprus population.
This mutation is not related to any disease, perhaps solely to an increased susceptibility to certain viruses, such as cytomegalovirus, herpes simplex virus, hepatitis C virus, and West-Nile virus.
Individuals who carry this mutation in homozygosity do not express the CCR5 chemokine receptor on their cells and are resistant to infection by HIV, whereas heterozygotes have greater resistance than the general population without the mutation, lower viral load, and slower progression to the full-blown stage of the disease, i.e., AIDS.
This assertion is confirmed by the case, reported in the Literature, of a patient with acute myeloid leukemia and HIV who subsequently underwent bone marrow transplantation from a donor carrying the CCR5-Δ32 mutation in homozygosity: after transplantation, a reduction in viral load was observed for 20 months, which also led to the possibility of discontinuing antiretroviral therapy.
Scientists have obviously speculated that this mutation could open new lines of research in HIV therapy; in this regard, it should be specified that our DNA, in the presence of mutations, puts in place compensatory mechanisms of protection against the loss or reduction of CCR5 function that are not present in case the mutation is "induced".
In fact, increased susceptibility to non-HIV-related infections has been observed by "silencing" the receptor pharmacologically, however, analysis of data from patients treated with cernicriviroc (the latest drug created on the basis of the protective hypothesis of the CCR5 mutation) has revealed the drug's antifibrotic power against another high-mortality disease: nonalcoholic steatohepatitis with fibrosis.
Research to combat HIV continues, the possibilities are many, and it is not ruled out that an effective therapy to combat this disease may be found.
There are currently only two cases reported in the Literature in which bone marrow transplantation has benefited blood cancer and, because a donor with the protective mutation against HIV had been reported, also against this viral infection. Two considerations remain: marrow transplant treatment is not suitable for all HIV-infected individuals as it can only be applied to those who have concomitant blood cancer, as the risks of this transplant are still high compared to antiretroviral treatment through the appropriate drugs; this observation has initiated new studies focused on gene manipulation of the CCR5 gene.