PHILADELPHIA, USAâ€”For the first time researchers have succeeded in making small number of patients with AIDS more resistant to HIV by infusing them with genetically modified immune cells.
A report in the New England Journal of Medicine describes how the expression of the CCR5 gene that codes for a receptor that enables HIV to infect immune cells was turned off.
The research has built on the knowledge that the rare people who naturally have one mutated CCR5 copy are more resistant to HIV while those with two copies are immune to it.
The investigators infused these genetically modified cells into 12 patients who were under treatment with antiretroviral therapy. In an interview the senior author of the study â€” Dr. Carl June, Professor in Immunotherapy at the Department of Pathology and Laboratory Medicine at the University of Pennsylvania in Philadelphia â€” told AudioMedica.com with MD-FM that they were able to resolve the main question arising with such approach â€” safety: â€œThere were no significant side effects,â€ he said. â€œThe first patient was treated in July of 2009 and still has had no side effects and still has engraftments â€” we can still find the genetically modified cells that are HIV resistant,â€ he noted.
Dr. June added that the infused cells survived and were more resistant to HIV than the patientsâ€™ own cells â€” even in those who were taken off anti-retroviral therapy (ART) for 3 months. The researchers are now going to increase the dose of infused cells and test the safety of longer treatment interruption.
Dr. Mark A. Kay MD, PhD, Professor in Pediatrics and Genetics
at Stanford University in California wrote an editorial the New England Journal mentioning some of the difficulties of implementing this as clinically: â€œThe technology is such that the number of cells that probably had both copies of the gene knocked out was pretty low and, ultimately, to get this to work on a level that could be used in patients for a real therapeutic benefit, would probably require an approach that would allow both genes to be knocked-out. You could then have much more resistance or totally resistance to most HIV strains,â€ he noted.
SOURCE: Tebas P. et al., Gene Editing of CCR5 in Autologous CD4 T Cells of Persons Infected with HIV, NEJM 2014;370:901-10. DOI: 10.1056/NEJMoa1300662.
LINK 1: http://www.nejm.org/doi/full/10.1056/NEJMoa1300662
Kay M.A. et al., Engineering Cellular Resistance to HIV, NEJM 2014;370:968-69. DOI: 10.1056/NEJMe1400593.
LINK 2: http://www.nejm.org/doi/full/10.1056/NEJMe1400593