Expression of CD44 and CD35 during normal and myelodysplastic erythropoiesis

• CD35 is an early marker of CD34+ erythroid-committed precursors.
• CD35 is expressed before CD105 in CD34+ erythroid-committed precursors.
• MDS patients display overall increased expression of CD44.
• Our data suggest that phenotypic alterations in MDS precede morphologic dysplasia.
• MDS patients with anemia show increased expression of CD117 vs. MDS without anemia.

Erythroid dysplasia is a common feature of myelodysplastic syndromes (MDS). Currently available information about the immunophenotypic features of normal and dysplastic erythropoiesis is scarce and restricted to relatively few markers. Here we studied the expression of CD117, CD35 and CD44 throughout the normal (n = 16) and dysplastic (n = 48) bone marrow erythroid maturation. CD35 emerged as an early marker of CD34+ erythroid-committed precursors, which is expressed before CD105 and remains positive thereafter. MDS patients (with and without morphologic dyserythropoiesis) displayed overall increased expression of CD44, associated with slight alterations on CD35 expression, suggesting that phenotypic alterations in MDS may precede morphologic dysplasia. In turn, MDS patients with anemia showed increased expression of CD117.