A London student diagnosed with an aggressive form of leukaemia has managed to find a stem-cell donor following a worldwide appeal. Lara Casalotti, 24, from Hampstead was diagnosed with acute myeloid leukaemia in December during a trip to Thailand.

Casalotti, who has Thai-Italian heritage, was told she faced a "needle in a haystack" search for a matching stem cell as only 3% of the world's registered donors are mixed race and she would most likely need to find someone with a similar ethnic background to herself. In a bid to find a match, her family teamed up with blood-cancer charity Anthony Nolan to launch the #Match4Lara appeal, working with donor registries in the UK, Thailand, America and Italy among others to appeal for more people from mixed-race and ethnic-minority backgrounds to sign up.

The campaign was backed by celebrities such as author JK Rowling, footballer Gareth Bale and Prime Minister David Cameron. Anthony Nolan has now confirmed it has been able to find a match for Casalotti following an "unprecedented spike" of new donors from black, Asian, ethnic-minority and mixed-race backgrounds in the UK during the campaign's peak. The family estimates that the number of people who have joined a stem-cell register globally because of the campaign has reached more than 20,000.

Ann O'Leary, head of register development at Anthony Nolan, said: "We're over the moon that we've been able to find a suitable donor for Lara and that she's now able to begin her transplant journey. We're so grateful to Lara and all of her incredible supporters for spreading the word about the simple but vital act of donating stem cells. By diversifying the donor register, they have given hope to so many other people from ethnic minority and mixed race communities.The life-changing impact of the Match4Lara campaign will be seen for years to come, as any one of the thousands of people they have signed up could save the life of someone like Lara in the future."

Casalotti, who is studying for a masters in global migration at UCL, said in a statement: "These past months have been a whirlwind but I am so thankful a donor with a genetic match has now been found. Thanks to everyone's immense support, I have always stayed hopeful that I would find one, but I realise how lucky I have been, given how difficult it was to find that donor. I want to keep urging people to sign up to the donor registries so that everyone can have a chance of finding their match. Let's find a 'Match4All'."

The donor's identity must be kept anonymous due to strict patient-donor confidentiality regulations. The blood-cancer charity said it is hoped they would donate their stem cells in March.