CD59 and bone marrow failure syndrome: Occasionally, CD55 and/or CD59 deficient clones are detected in non-cytopenic patients and patients with no apparent bone marrow failure syndromes and in about 4,1% in healthy volunteers (1.6, 0.8% and 1,6% with CD55−/CD59-, CD55−/CD59+, and CD55+/CD59- cells respectively) [8].