Spit4Mum was set up by Jonni and Caroline Berger, from Harrow in 2013, and resulted in 1,000 people joing the register, said Ms Rosselli.
Jonni Berger said: “We are very proud we have made a massive increase on previous numbers as a direct result of our campaign.
“It is great the community is coming together because it is harder for ethnic minorities to find a match."
Over 80,000 Londoners are signed up to the Anthony Nolan register, which was set up forty years ago to help find lifesaving matches for people with blood cancer.