[Abnormal changes in erythrocyte membrane proteins in hereditary spherocytosis and their relation to clinical and biological aspects of the disease]

Abstract

Background: In the present paper we report a study of 20 patients with hereditary spherocytosis (HS) performed with the aim of provide further information on the electrophoretic abnormalities of red blood cell (RBC) membrane proteins and their putative relationship with the clinical, biological and genetic aspects of the disease.

Methods: General hematological parameters, reticulocyte count, osmotic fragility test and erythrocyte morphology analysis, were performed by routine procedures. Membrane proteins of erythrocyte were analyzed by SDS-polyacrylamide gradient gel electrophoresis (SDS-PAGE) using the Laemmli and Fairbanks methods.

Results: In 8 out of 20 cases (40%) a defect of band 3, alone or associated with a slight deficiency of protein 4.2, was observed. In addition to the presence of spherocytes, in all these 8 patients, a peculiar morphologic RBC alteration called pincered RBCs was also observed. Moreover, 2 cases showed a deficiency of protein 4.2, 2 cases a deficiency of ankyrin and 2 cases a deficiency of spectrin. In 6 cases (30%) the electrophoretical pattern of the erythrocyte membrane proteins was normal. A significant (r = -0.6; p < 0.01) correlation between the protein 4.2 (pallidin) and the mean corpuscular haemoglobin concentration (MCHC) was found. Also, the multiple regression analysis showed a correlation (r2 = 0.6; p < 0.0001) between the amount of protein 2.1 (ankyrin) and two hematological parameters: the mean corpuscular volume (MCV) and the red cell distribution width (RDW).

Conclusions: The defect of band 3 is the most frequent membrane protein abnormality associated with HS.