Acquired alteration in the expression of blood groups in a patient with sideroblastic anemia and chronic renal failure.

A patient with well-differentiated lymphocytic lymphoma in remission presented with renal failure, sideroblastic anemia, and an acquired diminution in the expression of A antigen on his red cells. Other red cell antigens (H, M, i, and I) also were expressed weakly. Lewis antigen was expressed only in secretions. The diminished expression of the A antigen could not be accounted for by diminution in the specific glycosyl transferases responsible for its expression, since the activity in the serum of both the H enzyme (alpha 1 leads to 2 fucosyltransferase) and the A enzyme (alpha 1 leads to 3 N-acetylgalactosaminyltransferase) was not diminished. When sialic acid was removed by enzymatic treatment, the expression of the A and i antigens was augmented markedly, suggesting that the sialic acid may have altered the expression or detection of the antigens. This abnormality was probably related to dysplasia of the bone marrow which was otherwise manifest by ringed sideroblasts, unsegmented megakaryocytes, and diminished growth in vitro.