Expression of CD2 and activation markers on blood T-helper cell subsets inpatients with transfusional iron overload

The aim of the present study was to investigate the relationship between di fferent measures of iron status, and the expression of CD2, and the activat ion markers CD25, CD71, CD45RO, HLADR CD38 within the Th-cell subset in pat ients with progressive transfusional iron overload. We estimated the expres sion of the activation surface markers on the Th cells of peripheral blood by flow cytometry from 22 multiply transfused patients. The number of CD2 b inding sites (BS) on Th cells was significantly higher in the patients (82 917 +/- 30 801) than in age-matched normal controls (41 145 +/- 6989, P < 0 .0001). When investigating whether this difference could be due to the iron overload we found the number of CD2 BS closely related to the iron saturat ion of serum transferrin (TfS) (R-2 = 0.78, P < 0.001). The relationship to the serum ferritin concentration and to the number of blood units given wa s weaker, but also significant (R-2 = 0.22 P < 0.027, respectively, R-2 = 0 .21, P < 0.032). Also the fraction of mature memory Th cells which express CD45RO at a high level was directly related to the TfS (R-2 = 0.57, P < 0.0 001), while the expression of CD38 within the Tn cell fraction was inversel y related to the TfS (R-2 = - 0.43, P = 0.009). The expression of HLA-DR (b ut not of CD25 and CD71) was also directly related to the TfS (R-2 = 0.29, P = 0.01). Our results show a clear, statistical relationship between the i ron status and the expression of surface markers within Th cells in multipl y transfused patients.