Impaired Polymorphonuclear Leukocyte Function in Chronically Hemodialyzed Patients with Iron Overload

Polymorphonuclear (PMN) leukoyte function tests and clinical data analyses were performed in 28 chronic renal failure (CRF) patients receiving regular hemodialysis. We divided them into two groups; 12 patients with normal serum ferritin were classified as group 1 and 16 patients with high serum ferritin as group 2. There was no difference in age, BUN, serum creatinine, complement (C3, C4), peripheral white blood cell count and the duration of dialysis between the two groups, but the serum iron level was higher in group 2 (129.1 ± 46.58 μg/dl) than in group 1 (74.3 ± 20.9 μg/dl) (p<0.001). The total iron binding capacity was lower in group 2 (p<0.05) and the number of transfusions was higher in group 2 (25 ± 16.1) than in group 1 (12 ± 8.7) (p<0.05). The nitroblue-tetrazolium (NBT) test showed no difference among groups 1, 2 and the healthy control group. In chemotaxis to fMLP (N-formylmethionylleucylphenylalanine), the mean number of migrated neutrophils to fMLP (10(−6) M/L) per high power field was significantly decreased in group 2 (99.5 ± 37.6) compared with the healthy control group (140.1 ± 13.4) (p<0.005), but not in group 1 (155.8 ± 79.4). In the phagocytosis test using Staphylococcus aureus, the phagocytic index ratio compared to the healthy control group was significantly decreased in group 2 (0.59 ± 0.14), but not in group 1 (0.97 ± 0.18). These results suggest that iron overload due to multiple transfusions in patients receiving regular long term hemodialysis may play a part in causing susceptibility to infection by impairing PMN leukocyte functions, especially chemotaxis and phagocytosis.