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Genoma rediģēšanas veiktspēja bija zemāka par gaidāmo
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30.09.2019

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Ķīnas zinātnieki izmantoja CRISPR-Cas9, lai izārstētu AIDS 27 gadus vecam vīrietim. Viņam 2016. gadā noteica diagnozi AIDS, bet drīz noskaidrojās, ka viņam ir arī leikēmija, tāpēc vajadzēja steidzīgi uzsākt ārstēšanu. Vīrietim piedāvāja testēt kaulu smadzeņu transplantātu, kas apstrādšts, izmantojot tehnoloģiju CRISPR-Cas9, lai atbrīvotos no gēna CCR5. Pēc staru terapijas pacientam ievadīja paša šūnas, kas bija rediģētas.
19 mēnešus pēc eksperimentālās ārstēšanas, kas tika veikta 2017. gada vasarā, pacients bija sasniedzis pilnu remisiju attiecībā uz leikēmiju. Taču attiecībā uz infekciju īpašu uzlabojumu nebija: zinātniekiem izdevās izraisīt mutācijas tikai 17,8% no pacienta paņemtajās šūnās, tas ir, organismā to daudzums samazinājās par 5 - 8%. Ar tādu daudzumu nav pietiekami, lai uzveiktu HIV un izstrādātu organisma noturību pret to. 
Neraugoties uz ārstēšanas salīdzinoši nelielo efektivitāti, pētījuma vadošais autors Dengs Hongkui to uzskata par veiksmīgu, norādot uz to, ka pacientam pēc operācijas netika konstatētas negatīvas sekas un anomālijas.
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Source: TECHNOLOGY | «Scientists use CRISPR to Treat HIV for the First Time» | https://www.technology.org/2019/09/16/scientists-use-crispr-to-treat-hiv-for-the-first-time/ |
The patient in question – a 27-year-old male citizen of China – was diagnosed with AIDS back in 2016, and two weeks later found out he also had lymphoblastic leukaemia.
With prospects bleak, the patient was offered to receive a bone marrow transplant engineered with CRISPR-Cas9 to be free of the CCR5 gene known to produce a protein which the virus uses to gain access to an infected person’s cells.
After 19 months following the experimental treatment, performed in the summer of 2017, the patient achieved complete remission with regards to leukaemia, but was found to harbour the CCR5 edit in merely 5% to 8% of his bone marrow cells.
“In the future, further improving the efficiency of gene-editing and optimising the transplantation procedure should accelerate the transition to clinical applications,” said Deng Hongkui, lead researcher on a study published in The New England Journal of Medicine.
Despite the relatively slight efficacy of the treatment, Deng considers it a success, pointing out that it’s primary focus was to test the waters, namely – to find out if the procedure is feasible and safe, which, according to him, it almost certainly is.
The research team did not find any adverse effects associated with the intervention, yet longer-term and more in-depth studies remain indicated to identify potential “off-target effects” and to conduct “other safety assessments”.
The present study builds on research conducted in the past, such as the team’s – largely successful – experiment in transplanting edited CCR5 humans cells into mice with HIV, as well as similar experiments performed by other American research groups using an older gene-editing tool called zinc finger nuclease.
Hongkui’s and his team’s efforts form a part of China’s Five Year Plan announced in 2016, which lays out, among other things, the central government’s plan to invest heavily into biotech to generate a number of scientific breakthroughs and thereby maintain the country’s prestige within the scientific community.
Hongkui believes that not only does CRISPR brings the goal of a functional cure for AIDS that much closer, but could also “bring a new dawn” to the treatment of blood-related diseases, such as sickle cell anaemia, haemophilia, and beta thalassemia.