R. D. Baynes

The non-immune inflammatory response: Serial changes in plasma iron, iron-binding capacity, lactoferrin, ferritin and C-reactive protein

The interrelationships between various components of the non-immune inflammatory response (white cell count, plasma lactoferrin, C-reactive protein, ferritin, iron and iron-binding capacity), were studied serially in a variety of inflammatory conditions including acute lobar pneumonia, active pulmonary tuberculosis, rheumatoid arthritis on gold therapy and sepsis in the face of marrow hypoplasia induced by chemotherapy. Lactoferrin concentrations paralleled the white count in all groups. They were highest in pneumonia and tuberculosis, mildly elevated in rheumatoid arthritis and markedly decreased in neutropenic sepsis. Very high initial lactoferrin concentrations were associated with a poor prognosis in acute pneumonia. C-reactive protein and ferritin concentrations remained elevated through the period of study in acute pneumonia and neutropenic sepsis, while they gradually normalised over weeks in subjects with tuberculosis or rheumatoid arthritis on therapy. In pneumonia and tuberculosis moderate hypoferraemia and a reduced iron-binding capacity were evident. In contrast, a raised percentage saturation was present in neutropenic sepsis, probably related to erythroid marrow suppression. Comparisons between ferritin, lactoferrin and C-reactive protein in the various groups supported the concept that ferritin behaves in part as an acute phase reactant and that hypoferraemia in inflammation is due to deviation of iron into ferritin stores. The suggestion that lactoferrin is responsible for the hypoferraemia and hyperferritinaemia was not supported by the present data. Iron deficiency appeared to limit the hyperferritinaemic response in rheumatoid arthritis, while erythropoietic inhibition by chemotherapy dampened the hypoferraemic response in neutropenic sepsis.

Nutritional iron requirements and food iron absorption

Abstract Bothwell TH, Baynes RD, MacFarlane BJ, MacPhail AP (MRC Iron and Red Cell Metabolism Research Unit, Department of Medicine, University of the Witwatersrand Medical School, Parktown, Johannesburg, South Africa). Nutritional iron requirements and food iron absorption.

Severe deficiency of alpha1-antitrypsin associated with cutaneous vasculitis, rapidly progressive glomerulonephritis, and colitis

The association of vasculitis with severe deficiency of alpha 1-antitrypsin is rare. This report describes a 44-year-old man with severe deficiency of alpha 1-antitrypsin associated with diffuse vasculitis involving skin, kidney (rapidly progressive glomerulonephritis), and colon (colitis). Colitis has not previously been reported in association with deficiency of alpha 1-antitrypsin. Other reported cases are reviewed and the possible immunologic mechanisms underlying the association are discussed.

Enzyme linked immunosorbent assay for lactoferrin. Plasma and tissue measurements

Highly purified lactoferrin was obtained from human breast milk by sequential use of affinity chromatography and isoelectric focusing. IgG antibody to purified lactoferrin was used to develop a sensitive and reproducible enzyme linked immunosorbent assay. Characteristics of the assay included linearity over a wide range of lactoferrin concentration (3.125-200 micrograms/l) and sensitivity (lower range less than 1 microgram/l). The assay can be adapted for use on tissue cytosol as well as plasma. Healthy subjects showed plasma lactoferrin levels ranging from 187.5-450.1 micrograms/l. Pulmonary tuberculosis and acute pneumonia are associated with a 2-3-fold increase in plasma lactoferrin content while neutropenic subjects have markedly depressed lactoferrin concentrations. The assay will be useful for further delineation of lactoferrin and neutrophil function and turnover.

Phenotypic expression of the HLA linked iron‐loading gene in males over the age of 40 years: a population study using serial serum ferritin estimations

Abstract. The frequency of the HLA linked iron‐loading gene was assessed in 1783 Afrikaner men over the age of 40 years living in the South Western Cape. Measurements, made on three occasions over a 4.5 year period, included the serum ferritin concentration, a screening test for reduced unsaturated iron‐binding capacity and the percentage transferrin saturation. The serum γ‐glutamyl transferase concentration was used as a marker of alcohol abuse. The diagnosis of homozygosity was based on a serum ferritin concentration that was persistently > 400 μg l−1 and a percentage transferrin saturation > 55%. Using these criteria, 17 subjects were diagnosed as homozygous, corresponding to a disease frequency of 0.0095, a gene frequency of 0.0976 and a heterozygote frequency of 0.176 (95% confidence limits: 0.135–0.213). None of the subjects had overt clinical haemochromatosis. Typing for the HLA‐A, ‐B, ‐C and ‐DR loci showed that the HLA‐A3 allele (frequency 0.6471 and relative risk 4.4) was the only independent marker for the iron‐loading gene in this asymptomatic population. Using the present approach it was not possible to distinguish between heterozygotes, alcohol abusers and normal subjects with serum ferritin concentrations at the upper end of the normal range.

Persistent neutrophil activation in mild asthma

allergic cutaneous inflammation in viva. J Immunol 1991;146:521-8. 4. Bochner BS, Peachell PT, Brown KE, Schleimer RP. Adherence of human basophils to cultured umbilical vein vascular endothelial cells. J Clin Invest 1988;81:1355-60. 5. Kyan-Aung U, Haskard DO, Lee TH. Vascular cell adhesion molecule-l (VCAM-1) and eosinophil adhesion to cultured human umbilical vein endothelial cells in vitro. Am J Respir Cell Mol Biol 1991;5:445-50. 6. Hemler ME. VLA proteins in the integrin family: structure, functions and their role on leukocytes. Annu Rev Immunol 1990;8:365-400. 7. Walsh GM, Mermod J, Hartnell A, Kay AB, Wardlaw AJ. Human eosinophil, but not neutrophil, adherence to IL-l-stimulated human umbilical vascular endothelial cells is alpha 4 beta 1 (very late antigen-4) dependent. J Immunol 1991;146:341923.

Relationship between Absorption of Inorganic and Food Iron in Field Studies

Food iron absorption data on 853 Indian women were compared to the haemoglobin concentrations, other iron-related measurements and the absorption of a reference dose of 3 mg iron given as ferrous ascorbate. The serum ferritin concentration was identified as the best predictor of the absorption of the reference dose (r = -0.54, p less than 0.0001). These two measurements were then compared in terms of their relative ability to predict the absorption of iron from 10 individual meals. Results were comparable, with correlations for the pooled data of -0.50 (p less than 0.0001) for the serum ferritin and 0.47 (p less than 0.0001) for the reference dose. Since serum ferritin is a simple and non-invasive test, it may represent the more satisfactory way of standardising food iron absorption results to a common iron status in field studies. However, the value of such an approach is limited by the wide confidence limits of the relationship between food iron absorption and both the other measurements.

A Systematic Evaluation of Bathophenanthroline, Ferrozine and Ferene in an ICSH-Based Method for the Measurement of Serum Iron

The chromogenic substrates ferrozine and ferene were compared to bathophenanthroline disulphonic acid for the measurement of iron concentrations in aqueous and serum samples in an assay based on that of the Iron Panel of the International Committee for Standardisation in Haematology. Ferrozine and ferene were more sensitive than bathophenanthroline. Copper at physiological concentrations in plasma caused only minimal positive interference with all three chromogenic substrates when thioglycollic acid was used as the reducing agent, but when ascorbic acid was used significant positive interference occurred with ferrozine and ferene. Interference due to contaminating haem was comparable with all agents. Bilirubin and carotene produced no interference. Profound reductions in colour development were noted with EDTA plasma.

Factors Involved in the Regulation of Iron Transport through Reticuloendothelial Cells

Abstract The effects of various maneuvers on the handling of 59Fe-labeled heat-damaged red cells (59Fe HDRC) by the reticuloendothelial system were studied in rats. Raising the saturation of transferrin with oral carbonyl iron had little effect on splenic release of 59Fe but markedly inhibited hepatic release. Splenic 59Fe release was, however, inhibited by the prior administration of unlabeled HDRC or by the combination of carbonyl iron and unlabeled HDRC. When carbonyl iron was administered with unlabeled free hemoglobin, the pattern of 59Fe distribution was the same as that observed when carbonyl iron was given alone. 59Fe ferritin was identified in the serum after the administration of 59Fe HDRC but the size of the fraction was not affected by raising the saturation of transferrin. Sizing column analyses of tissue extracts from the spleen at various times after the administration of 59Fe HDRC revealed a progressive shift from hemoglobin to ferritin, with only small amounts present in a small molecular weight fraction. The small molecular weight fraction was greater in hepatic extracts, with the difference being marked in animals that had received prior carbonyl iron. The increased hepatic retention of 59Fe associated with a raised saturation of transferrin was reduced by a hydrophobic ferrous chelator (2,2′-bipyridine), a hydrophilic ferric chelator (desferrioxamine), and an extracellular hydrophilic ferric chelator (diethylene-triaminepentacetic acid). Transmembrane iron transport did not seem to be a rate-limiting factor in iron release, since no differences in 59Fe membrane fractions were noted in the different experimental settings. These findings are consistent with a model in which RE cells release iron from catabolized red cells at a relatively constant rate. When the saturation of transferrin is raised, a significant proportion of the iron is transported from the spleen to the liver either in small molecular weight complexes or in ferritin. Although a saturated transferrin has no effect on the release of iron from reticuloendothelial cells, prior loading with HDRC conditions them to release less iron.

The fate of intravenously injected tissue ferritin in pregnant guinea-pigs

Summary. The organ distribution of intravenously injected hepatic ferritin either labelled with 59Fe or with 19Fe and 125I, was studied in pregnant guinea‐pigs. At 5 h 71.2% of injected 59Fe was present in the placenta and fetus. Transfer of 59Fe to the fetus was slow, with 11.2% present at 5 h and 38.6% at 21 h. Analysis of a placental cellular lysate for 59Fe and 125I revealed that the injected iron was present as intact ferritin at 2 h but by 21 h the ferritin had been catabolized the 125I excreted and the 59Fe incorporated into endogenous ferritin. Most of the fetal 59Fe counts were detected in the liver, with 35.3% of the transferred 59Fe in ferritin, 30.4% in haemoglobin and 10.6% in a low molecular weight pool. The uptake of labelled ferritin by the placenta was inhibited by a 300‐fold molar excess of unlabelled ferritin but not by albumin, asialofetuin or by the injection of carbon particles. A nonsignificant reduction in uptake was noted after injection of mannosylated bovine serum albumin. The mannosidase inhibitor swainsonine had no effect. Iron transfer to the fetus was not affected by various microtubular inhibitors. Presaturation of endogenous transferrin with oral carbonyl iron prevented iron release from the feto‐placental unit back into the maternal circulation. In consequence, marrow 59Fe uptake by the maternal marrow was reduced. The ferrous chelator 2,2′‐bipyridine significantly reduced 59Fe transfer to the fetus and this occurred irrespective of whether the chelator was given prior to or after 59Fe ferritin administration. The ferric chelator desferrioxamine had no such effect. Electron microscopy of placental tissues revealed endocytosis of ferritin molecules. These results indicate that the guinea‐pig placenta takes up homologous tissue ferritin and transfers the iron slowly to the fetus after reductive mobilization. The process is compatible with a receptor‐mediated pathway.