**6. Conclusions**

Stage 5 CKD is associated with an altered structure of erythrocyte membrane proteins, which may be due to the disease itself and/or to the interaction of blood cells with haemodialysis membranes. Haemodialysis procedure seems to contribute to a disturbance in the erythrocyte membrane protein structure, as showed by the significant reduction in spectrin, the most striking change observed.

Fig. 5. In stage 5 CKD patients, the increased plasma levels of elastase can induce changes in erythrocyte membrane proteins, leading to a decrease in the erythrocyte lifespan and, consequently, to increase the degree of anaemia in these patients.

Moreover, stage 5 CKD patients under haemodialysis also present higher elastase plasma levels, which might reflect the rise in neutrophils and the enhanced inflammatory process found in these patients. Haemodialysis procedure seems to be associated with neutrophil activation, with subsequent elastase release that seems to induce changes in the erythrocyte membrane protein composition, probably contributing to a decrease in the erythrocyte halflife, and, therefore to the anemia found in stage 5 CKD patients (Fig. 5).
