Degradation of glycophorin A of human erythrocytes in patients with myelo‐ or lymphoproliferative disorders: possible role of neutrophil proteases

Abstract

We have previously reported that glycophorin A (GPA) of human erythrocytes (carrying blood group M and N determinants) was totally digested by incubation of erythrocytes with human neutrophil elastase (HNE) and cathepsin G (CathG). The membrane‐bound GPA fragments fractionated by SDS‐PAGE gave characteristic patterns of bands detected by immunoblotting with the monoclonal antibody PEP80. Erythrocytes were incubated with HNE and CathG at low enzyme concentrations, similar to those found in vivo. Characteristic electrophoretic patterns of bands derived from a partial GPA digestion were observed and these patterns were different for both enzymes and different from those obtained after total GPA digestion. GPA was also partially digested by incubation of erythrocytes with granulocytes in the presence of Ca2+ and calcium ionophore and electrophoretic pattern of digestion products was similar to that obtained with low doses of HNE. No GPA digestion products were detected after treatment of erythrocytes with plasmin and kallikrein. Untreated erythrocytes of 21 patients with various myelo‐ or lymphoproliferative disorders were tested by SDS‐PAGE of RBC membranes and immunoblotting with the anti‐GPA PEP80 antibody. GPA degradation products, resembling those formed by a mild CathG treatment of control RBC, were detected in nine patients. GPA fragmentation was in some cases accompanied by a reduced expression of blood group MN determinants. No distinct relation was observed between the occurrence of GPA degradation in erythrocytes and increases in plasma concentrations of HNE‐α1‐proteinase inhibitor (α1‐PI) complex considered to be an indication of a release of neutrophil proteinases in vivo. However, the results suggested that a partial GPA degradation in haematological proliferative disorders may occur due to limited proteolysis by neutrophil proteinases, most likely by CathG.

Neutrophil Cathepsin G Enhances Thrombogenicity of Mildly Injured Arteries via ADP-Mediated Platelet Sensitization

“…Prolonged bleeding times in anemia are corrected upon normalizing the hematocrit [ 35 ] and intact erythrocytes enhance the collagen-induced platelet responsiveness, via mechanisms that include the release of ADP [ 36 ]. Moreover, cathepsin G digests red blood cell membrane proteins, such as glycophorin A, B and C [ 37 , 38 ], resulting in cell membrane damage, facilitating the leakage of ADP from these cells. This interpretation is supported by the observation that anti-hemolytic drugs, such as chlorpromazine prolong the bleeding time by decreasing plasma ADP-levels [ 39 ].…”

Eryptotic Phenotype in Chronic Myeloid Leukemia: Contribution of Neutrophilic Cathepsin G

“…In an in vitro study, neutrophilic elastase and cathepsin G are reported to degrade glycophorins on erythrocyte membrane [8]. The same group has shown degradation of glycophorins on the surface of erythrocytes from patients with myeloproliferative disease and attributed it to elastase [9]. Our study for the first time demonstrates the role of cathepsin G in the cleavage of erythrocyte band 3 in chronic myeloid leukemia (CML).…”

Classification of Standard Alleles of the MN Blood Group System

“…Genotyping of this system has been informative in the forensic and anthropological fields. It also has clinical importance, since somatic mutations at the GPA loci often occur in patients with such diseases as ataxia telangiectasia [2], aplastic anaemia, paroxysmal nocturnal haemoglobinuria [3]and haematological proliferative disorders [4], and in patients who have received cancer chemotherapy and radiotherapy [5, 6, 7]. …”