Effect of the Erythrocyte Apheresis On Immunological Parameters in Sickle Cell Anemia Patients in Crisis Period.

Between February 2009 and June 2009, 37 patients (20 female / 17 male) received 44 apheresis treatments at Hemapheresis Unit of Cukurova University School of Medicine, Adana, Turkey. The median age was 22 (Range, 4-56) years and the mean body weight was 51.9±18.6 kilograms. The apheresis procedures were carried out using a Cobe Spectra Cell Separator. A mean of 1.77 body volume calculated red blood cell volumes were exchanged with a mean duration of 125.9±34.9 minutes (Table 1). Sickling negative and leukoreduced packed red cells were used for apheresis treatments. Hemoglobin electrophoreses, complete blood counts, immunoglobins, specific surface markers for T, B and natural killer (NK) cells were performed before and after each procedure. While three patients had a SCA-induced functional asplenia, none of the patients was HIV-seropositive.

The erythrocyte apheresis resulted in a decrease on white blood cell (WBC) counts as expected. Average pre and post apheresis WBC counts were 12883±5775/mm³ and 8506±3331/mm³ (p<0.001) respectively. Accordingly, a decrease in post procedure lymphocyte, monocyte and granulocyte counts was observed. Because small amounts of patient's plasma were removed with red blood cells during apheresis procedures, serum levels of immuglobulins were also decreased. CD3, CD4 and CD8 for T cells, CD11b for monocytes, CD20 for B cells, CD56 as a NK marker and CD45 for leukocytes were analyzed and all of surface markers showed an increase after erythrocyte apheresis. The average pre apheresis HbS level was 78.90±19.20%, whereas the mean post apheresis HbS level was found to be 23.85±13.27% (p<0.001) (Table 2).

The erythrocyte apheresis is an effective and rapid procedure to reduce HbS concentration without increasing blood viscosity. Apheresis treatments have also been found to be beneficial in decreasing the leukocyte counts and serum immunoglobulins levels in the blood. Flow cytometric analyses revealed that T, B and NK cells were increased after apheresis treatment. Interestingly, the change in CD4/CD8 ratio was not statistically significant (p>0.05). This shows that vascular wall integrity is maintained and apheresis can be safely performed in SCA patients. In our study, blood perfusion was restored and blood chemistry was improved to optimal levels after erythrocyte apheresis. As a result, crisis periods were shortened.

No relevant conflicts of interest to declare.