The doctors found no trace of HIV in the body of the patient during the 30 months after bone marrow transplantation. This is the second case in history when a stem cell transplant could cure HIV. The decisive factor, apparently, was the complete replacement of their own T-lymphocytes of the patient to the donor. A report published in the journal The Lancet.
Until recently, the man who was found with the human immunodeficiency virus, had only two opportunities to become infected and life to take antiretroviral drugs to prevent the spread of infection, or not to let him into their cells. Resistance is determined by a gene CCR5 — it encodes a protein on the surface of lymphocytes, which binds to the virus before you get inside. If this gene is missing a small section (this mutation called CCR5Δ32), then it turns out defective protein, the virus to him not joining, and the person is not infected.
In 2007, it became clear that there is a third way to acquire stability along with other lymphocytes. The patient named Timothy ray brown (who is know as the “Berlin patient”) transplanted hematopoietic stem cells from a donor with a mutation of the CCR5Δ32, and three years later it turned out that the HIV in the body brown is no more. However, repeat this procedure on other patients, the doctors were in no hurry: transplantation of bone marrow involves many risks and is often for humans it is much safer to continue with the standard therapy of HIV.
In March 2019, the doctors said that one more patient will probably repeat the fate of Timothy brown, it was dubbed the”London patient”. “London patient” was HIV positive for almost ten years when he was diagnosed with Hodgkin’s lymphoma stage four. Doctors quickly managed to find a few suitable bone marrow donor — and one of them was a carrier of the mutation CCR5Δ32. After almost a year and a half after transplantation, when the lymphoma patient is cured, the doctors found that the vast majority of lymphocytes in the blood of the patient — donor, that is resistant to infection. In the experiment, the patient stopped taking antiretroviral therapy, and since then doctors are closely monitoring his health.
By March 2019 the London patient and a half years he lived without medication for HIV infection, however to do definitive conclusions, no one dared — too little time has passed after transplantation. Now another year passed: “London patient” told the newspaper The New York Times the story of his treatment and his doctors — Ravindra Kumar Gupta (Ravindra Kumar Gupta) from the University of Cambridge together with colleagues published their observations of his condition.
Within 30 months after the transplant doctors analyzed samples of blood, semen, cerebrospinal fluid, and biopsy of the lymph nodes and intestines of the London patient. In biological fluids, viral genomes could not be found. The limit of detection of the analysis does not allow to unambiguously conclude that a single viral particle in the patient’s body is no more, however, if they remained in trace amounts. The number of T-lymphocytes, which decreases during HIV infection, increased and approached the values before transplantation. In some of them the researchers found the remnants of viral genomes — less than 2-3 per million cells, but this result may be false positive.