Myeloid surface antigen abnormalities in myelodysplasia: relation to prognosis and modification by 13-cis retinoic acid.

The relation between prognosis and lineage specific surface antigen expression on peripheral blood granulocytes and monocytes was studied using monoclonal antibodies and flow cytometry in 37 patients with myelodysplastic syndromes (MDS). Abnormalities in antigen expression were summarised as a score, and cases were divided into low (few abnormalities) and high (many abnormalities) groups. Survival was significantly worse in the "high" group (logrank chi 2 = 5.793, p = 0.016), this group having a median survival of 31 weeks, compared with more than 67 weeks in the "low" group. No correlations were found between the score and any of the following: peripheral blood platelet and granulocyte count; FAB subtype; bone marrow blast cells and sideroblast count, or erythroid and myeloid progenitor growth. Antigen expression was also studied in six further cases of MDS before and after six weeks of treatment with 13-cis retinoic acid (CRA), 20 mg given orally, and a comparison was made with six untreated patients studied before and after a similar time interval. In the treated group 58% of initially abnormal measurements reverted to normal, compared with 24% in the untreated group. Five of the six treated patients showed a decrease in the score, whereas only two of the six improved in the untreated group. The data indicate that myeloid antigen expression is a useful indicator of prognosis in MDS, and that antigen expression may be affected by treatment.