Uniparental expression of HLA in AA cases with CNN-LOH in 6p. Allele-specific expression of HLA-A antigens in AA specimens was examined by flow cytometry using monoclonal antibodies that specifically recognize the indicated HLA types (red lines), where leukocytes from healthy persons were used as a control (blue lines). (A-B) The uniparental expression of HLA-A antigens in PB leukocytes and BM CD34⁺ cells obtained from 3 AA cases with CNN-LOH in 6p. Different leukocyte compartments were separately examined, including granulocytes (G), monocytes (M), B-lymphocytes (B), and T-lymphocytes (T).