Granulocyte dysplasia and dysfunction, and CD11/CD18 defects in myelodysplastic syndromes.

In myelodysplastic syndromes (MDS), dysplastic changes in neutrophils are a common feature reflecting the total degree of bone marrow dysplasia. Furthermore, granulocyte function is abnormal, so that a high risk of life-threatening infections has been documented. In this review we shall focus on the defects of both granulocytes and their CD11b/CD18 glycoprotein complex, which regulate granulocyte adherence, locomotion, diapedesis and migration into inflammatory sites, in patients suffering from primary MDS. The defective surface membrane glycoprotein expression of myelodysplastic phagocytes is not only a useful diagnostic tool, but also a powerful prognostic one, since MDS patients with such defects present both an increased susceptibility to infections and a decreased survival. Moreover, the administration of colony-stimulating factors is known to be able to elicit long-lasting improvement in neutrophil count, CD11b/CD18 expression and function, marrow myeloid maturation, and possibly to decrease bacterial infections in MDS patients.