If it is not found, then the nearest matching combination present on the system is used.

如果未找到，则使用系统上存在的最接近的匹配组合。

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Mrs Berger, 61, from from Harrow, north-west London, suffers from myelodysplastic syndrome and has a combination of rare tissue types, making finding a matching donor more difficult.

BBC: Caroline and Sharon Berger

Mrs Berger, from Harrow, north-west London, has a combination of rare tissue types that has made finding a matching donor more difficult.

BBC: Urgent plea for bone marrow donor