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Iron, absorption, hepcidin, anemia, inflammation
tors of SHep were Hb (b= 0.520; P<0.01) and IL-6 (b= 0.508; P<0.001). In the non-anemic group, at baseline, erythrocyte iron incorporation significantly correlated with SF (r=-0.822; P<0.001), SHep (r=-0.792; P<0.001), EPO (r=0.631; P<0.01) and Hb (r=-0.475; P<0.05); at 24 h after vaccination, incorporation significantly correlated with SHep (r=-0.708; P<0.001), Hb (r=-0.563; P<0.01) and serum iron (r=0.516; P<0.05). In the IDA group, at baseline and at 24 h after vaccination, erythrocyte iron incorpora- tion was not significantly correlated with Hb, iron bio- markers, SHep or EPO. In the regression analysis including all subjects, sTfR, Hb, EPO and IL-6 explained 53% and 50% of the variation of erythrocyte iron incorporation at baseline and at 24 h after vaccination, respectively. In all subjects, the only significant predictor of erythrocyte iron incorporation was Hb, both at baseline (b= -0.410; P<0.05) and 24 h after vaccination (b= -0.659; P<0.01). In the regressions including all subjects, SHep, Hb, EPO and IL-6 explained 61% and 38% of the variation of serum iron at baseline and at 24 h after vaccination, respectively. At baseline in all subjects, significant predictors of serum iron were Hb (b=0.549; P<0.01) and EPO (b=-0.333; P=0.05). In contrast, at 24 h after vaccination, significant predictors of
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serum iron were Hb (b= 0.864; P<0.01), SHep (b= -0.449; P<0.05) and IL-6 (b= 0.347; P<0.05).
Discussion
Our main findings are that at 24-36 h after vaccination: 1) there was a comparable 2-3-fold increase in serum IL-6 in both groups (P<0.001); 2) there was a significant >2-fold increase in SHep in the non-anemic group (P<0.001), but no significant change in SHep in the IDA group; 3) serum iron decreased only in the non-anemic group (P<0.05); and 4) there was no significant change in erythrocyte iron incorpo- ration in either of the two groups; incorporation was approximately 2-fold higher in the IDA group both before and after vaccination (P<0.001).
Previous experimental human studies have examined the hepcidin response to inflammation.10,11 In healthy adults given an infusion of IL-6 (iron status was not reported but subjects were presumably non-anemic), after 2 h urinary hepcidin increased 7.5-fold, while serum iron and TSAT decreased by 33-34%.11 In healthy adults injected with LPS (iron status was not reported but subjects were presumably
Figure 2. Interleukin-6 (IL-6) and hepcidin response to influenza/diphtheria- tetanus-pertussis (DTP) vaccination. (A) Serum IL-6 and (B) serum hep- cidin concentrations before and at 8, 24 and 36 hours (h) after vacci- nation in the iron defi- ciency anemia (IDA) group (n=21) and the non-anemic group (n=22). BL: baseline.
Figure 3. Effects of influenza/diphtheria- tetanus-pertussis (DTP) vaccination on serum iron and erythrocyte iron incorporation. (A) Serum iron and (B) erythrocyte iron incorporation (iron absorption and utiliza- tion) at baseline (n=46) and at 24 hours (h) after vaccination (n=43) in the iron deficiency ane- mia (IDA) group and the non-anemic group.
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haematologica | 2019; 104(6)
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