Impact of C-reactive protein on absolute reticulocyte count in haemodialysis patients: the role of iron status

Abstract

The exact mechanisms by which the effects of inflammation on erythropoiesis occur are still to be determined. We aimed to examine the relation between C-reactive protein (CRP) and erythropoiesis as quantified by the absolute reticulocyte count (RTC) and the possible effect of iron status on this relationship. As part of a study that follows the changes of haematologic parameters after the intravenous (IV) administration of iron in 93 stable haemodialysis (HD) patients, we made a cross-sectional analysis of baseline measurements and an analysis of changes in RTC 1 week after baseline measurements and iron administration. Multiple linear regression analysis revealed that RTC had a positive correlation with CRP; RTC had a negative correlation with reticulocyte haemoglobin content (CHr). An interaction was also found between CRP and CHr in that CRP had a significant relation to RTC only in those patients whose CHr was more than 31.2 pg. At lower values of CHr, the correlation between CRP and RTC was not significant. Five days after the IV administration of 200 mg iron sucrose, a significant increase of RTC was observed, only in those patients with elevated baseline CRP levels who also showed an increase in CHr levels from ≤ 31.2 pg at baseline to ≥ 31.2 pg post-administration, supporting the presence of an independent positive correlation between CRP and RTC when iron is adequate. It is indicated that, in HD patients, elevated CRP values are associated with increased erythroid production only when CHr is quite satisfactory.