Lactoferrin In Plasma Research Articles

Vitamin d-binding protein (VDBP) and lactoferrin (LF) in plasma and peritoneal fluid (PF) in the diagnosis of endometriosis

Vitamin d-binding protein (VDBP) and lactoferrin (LF) in plasma and peritoneal fluid (PF) in the diagnosis of endometriosis

The Influence of Lactoferrin in Plasma and Peritoneal Fluid on Iron Metabolism in Women with Endometriosis.

The aim of this study was to investigate the relationship between lactoferrin and iron and its binding proteins in women with endometriosis by simultaneously measuring these parameters in plasma and peritoneal fluid. Ninety women were evaluated, of whom 57 were confirmed as having endometriosis. Lactoferrin was measured by ELISA, transferrin, ferritin and iron on a Cobas 8000 analyser. Lactoferrin and transferrin in peritoneal fluid were lower compared to plasma, in contrast to ferritin and iron. In plasma, lactoferrin showeds associations with iron and transferrin in endometriosis and with ferritin in the group without endometriosis. Lactoferrin in peritoneal fluid correlated with lactoferrin, iron and transferrin of plasma in patients without endometriosis. The ratio of lactoferrin concentration in peritoneal fluid to plasma differentiated stage I versus IV of endometriosis and was negatively correlated with the iron ratio in patients without endometriosis. The ferritin ratio differentiated women with and without endometriosis. The very high ferritin ratios, especially in advanced stages of endometriosis, suggest the protective involvement of this protein in peritoneal fluid and the loss of this role by lactoferrin. The results demonstrate the validity of assessing iron metabolism in women with endometriosis, which may be useful as a marker of the disease and its progression.

Plasma lactoferrin levels in newborn infants with early-onset neonatal sepsis

Objective: To determinate if lactoferrin (LF) could be optimal biomarker; the LF levels in plasma were compared between neonates with or without early-onset neonatal sepsis (EOS). Methods: From January to December of 2019 we conducted an analytic cross-sectional study, eighty-nine patients were collected: 34 newborns with EOS and 55 newborns without EOS from neonatology unit from a tertiary care hospital. The diagnosis was made with clinical parameters and sepsis biomarkers. Plasma concentrations of LF were measured by Enzyme-Linked Immunosorbent Assay (ELISA). Results: The LF median was 3.7ng/ml to the newborn group with EOS while 44.8ng/ml was to newborn without EOS (p: 0.000). The best LF cut-off point in newborns with EOS was 20.55ng/ml, with sensitivity of 73.5%, specificity 92.7%, positive predictive value 86.2%, and negative predictive value 85%, positive likelihood ratio 10.11, and negative likelihood ratio 0.28. Conclusions: These findings indicate that levels of LF in plasma could be an effective and useful biomarker to diagnose of EOS.

Gene expression of renal lactoferrin and glycemic homeostasis in diabetic rats with reference to the protective role of exogenous bovine lactoferrin

BackgroundThis study is intended to clarify the influence of exogenous bovine lactoferrin (bLf) treatment on glycemic homeostasis, gene expression, and production of lactoferrin (Lf) in rats with experimentally induced diabetes.MethodologyFifty adult male rats were used; 15 rats were used as the normal control rats (group A) and were injected an intraperitoneal (I/P) with 1 ml of isotonic saline daily for 3 months. Thirty-five rats were administered I/P injection of 60 mg of streptozotocin per kilogram body weight to induce diabetes. Thirty streptozotocin-treated rats were selected and used as diabetic rats, and they were subdivided into 2 equal groups (15 rats each): the untreated diabetic group (group B) and treated diabetic group (group C). The rats in the diabetic group were administered an I/P injection of 1 ml of isotonic saline daily for 3 months, while rats in the diabetic treatment group were administered an I/P injection of 300 mg of bLf/kg body weight/day/3 months. At the end of the experiment, blood and renal tissue samples were collected from all rats. The levels of insulin, glucose, and lactoferrin in plasma were measured. Homeostatic model assessment for insulin resistance (HOMA-IR) was performed. The numbers of Lf-mRNA copies in renal tissue were assessed using quantitative RT-PCR. To measure Lf production in renal tissue, Western blot analysis was applied.ResultsThe obtained data demonstrated that the treatment of diabetic rats with bLf maintained glycemic homeostasis at normal levels but increased the mRNA expression of renal Lf.ConclusionIn diabetic rats, bovine lactoferrin treatment offers the potential for protection against incidences of insulin resistance (IR) by stimulating the suppressed expression and production of the LTF gene.

45 ACROSOME REACTION AND HETEROLOGOUS ZONA BINDING ASSAY OF FROZEN STALLION SPERM AFTER HYPERACTIVATION

During cryopreservation and due to the large portion of seminal plasma removal, there is a decrease in equine sperm antioxidant protection. Lactoferrin and catalase in seminal plasma play an antioxidant role. The fertilizing ability of equine sperm has been analysed in vitro using sperm-zona binding assays with heterologous oocytes. The results have been correlated with in vivo fertility by means of acrosome reaction (AR) and the number of attached sperm to the zona pellucida (ZP). The aim of the present work was to estimate the potential fertilizing ability of stallion sperm frozen with INRA82 extender (Battelier et al. 1997) with lactoferrin and catalase, and after hyperactivation with procaine and calcium ionophore A-23187 (Ca-I) by determining the AR rate and number of attached sperm to the bovine ZP. Semen from 6 stallions was frozen with 3 extenders: (T1) control, INRA 82; (T2) T1 + 500 μg mL–1 lactoferrin; and (T3) T1 + 200 IU mL–1 catalase. After semen thawing, the sperm were selected by swim-up and distributed in 3 aliquots according to the hyperactivation treatments: (H1) control, after thawing; (H2) capacitating Whitten’s medium + 5 mM procaine chloride; and (H3) capacitating Whitten’s medium + 5 μM Ca-I. To the zona binding assays, bovine oocytes derived from abattoir ovaries were incubated at 38.5°C with 5% CO2 (1 h), and 5 oocytes were poured into each treatment droplet under mineral oil. Sperm were stained with Hoechst 33342 dye (35 μg mL–1), and after 2 h co-culture, the number of sperm attached to the ZP was determined with epi-fluorescent microscopy. The rate of sperm AR was determined after freezing-thawing (control) and hyperactivation treatments with propidium iodide and fluorescein isothiocyanate/peanut agglutinin dies with a flow cytometer. The green fluorescent (peanut agglutinin+) and not red stained (propidium iodide) sperm were considered acrosome reacted. Means of ZP attached sperm and percentage of AR sperm were analysed by ANOVA and Tukey test. A probability of P < 0.05 was considered significant. The mean of ZP attached sperm (4.2 ± 3.5) and AR sperm rate (4.4 ± 3.7%) did not differ among the extenders (P > 0.05). The rate of sperm AR after hyperactivation with procaine (5.2 ± 2.4%) did not differ to the Ca-I (6.1 ± 3.7%); however, they were higher than the spontaneous AR rate (1.1 ± 0.5%, P < 0.05). Lower number of ZP attached sperm was observed by the Ca-I induced hyperactivation protocol (1.9 ± 2.1) compared with the procaine (5.9 ± 3.7; P < 0.05), although they did not differ to the control (3.3 ± 2.7). In conclusion stallion frozen sperm were better hyperactivated with procaine than with Ca-I, and therefore, it is a more suitable sperm hyperactivation inductor to study equine IVF protocols with frozen semen. Acknowledgments are extended to CAPES, Brazil, for the financial support.

Semen lactoferrin promotes CCL20 production by epithelial cells: Involvement in HIV transmission.

To study the effect of seminal plasma on Chemokine (C-C motif) ligand 20 (CCL20) production by epithelial cells and its relationship with lactoferrin. HEC-1A cells, a cell line derived from a monostratified endocervical epithelium, were incubated with samples of seminal plasma (diluted 1:10 in culture medium) recovered from human immunodeficiency virus (HIV) seronegative (HIV-) or HIV seropositive (HIV+) subjects. Recombinant human interleukin 1 beta (IL-1β) was used as positive control, and culture medium only as negative control. The measurement of CCL20 production in the supernatants of HEC-1A cells and of lactoferrin in seminal plasma was determined by enzyme-linked immunosorbent assay techniques. A fractionation of seminal plasma proteins was performed by ion exchange chromatography on a pool of seminal plasma specimens from HIV- subjects. Each fraction was tested for its ability to stimulate the production of CCL20 by HEC-1A cells and for its lactoferrin concentration. The HIV viral load in seminal plasma samples from HIV+ patients was measured using the HIV-Monitor kit (Roche Diagnostic Systems, Branchburg, NJ, United States). The positive control IL-1β was responsible for an increase of 11.36 ± 3.36 times in the production of CCL20. Stimulation of HEC-1A cells was performed in 34 seminal plasma samples (22 from HIV+ subjects and 12 from HIV- subjects). The mean production of CCL20 by HEC-1A in presence of seminal plasma from HIV- and HIV+ subjects was respectively 5.38 ± 0.91 and 7.57 ± 3.26 times higher than that obtained with the untreated cells (P < 0.05 between the two groups). Using the same 34 specimens of seminal plasma, no correlation was observed between the concentration of total proteins in seminal plasma and their ability to stimulate the secretion of CCL20 by HEC-1 cells. In contrast, the ability to produce CCL20 by HEC-1A cells correlated to the concentration of lactoferrin in the seminal plasma samples (r coefficient = 0.56; CI: 0.26-0.76; P < 0.001). After fractionation by ion exchange chromatography, the seminal plasma fractions exhibiting the highest concentrations of lactoferrin were responsible for the greatest stimulation of CCL20 production by HEC-1A cells (r coefficient = 0.89; CI: 0.78-0.95; P < 0.0001). Lactoferrin present in seminal plasma correlated with an increased production of CCL20 by HEC-1A cells and therefore could facilitate HIV entry through the genital mucosa.

Lactoferrin: a review

This review discusses the biological properties of the glycoprotein lactoferrin. Lactoferrin has been identified in secretions from exocrine glands and in specific granules of neutrophils. After degranulation, neutrophils become the main source of lactoferrin in blood plasma. Lactoferrin possesses various biological functions, including roles in iron metabolism, cell proliferation and differentiation, and antibacterial, antiviral, and antiparasitic activity. Many of these functions do not appear to be connected with its iron binding ability. Of late, lactoferrin concentrations have been measured mostly in humans but also in some other species. However, the relationship between its concentration and physiological or pathological effects on body functions is not yet well characterised.

Dauersubstitution bei homozygotem α1-Antitrypsin-Mangel: Einfluß auf das Proteinasen-Antiproteinasen-Gleichgewicht in Plasma und Sputum

Long-term replacement with human alpha 1-antitrypsin (60 mg/kg once a week intravenously) was carried out in seven patients with homozygous alpha 1-antitrypsin deficiency (7 males, mean age 50.8 [40-59] years) and progressive pulmonary emphysema for an average of 16 (13-20) weeks. After at least 12 weeks' therapy the concentrations of alpha 1-antitrypsin, elastase-alpha 1-antitrypsin complex, alpha 2-macroglobulin, lactoferrin and elastase inhibition capacity in plasma and sputum were assayed, these assays being performed before starting the alpha 1-antitrypsin infusion and at various times during the following week. After the infusion the plasma concentration of alpha 1-antitrypsin rose from a depressed initial level (median 1.22 g/l) to a level approximately five times higher (median after 1 hour: 5.96 g/l, P less than 0.001), and then declined exponentially, though it never fell below the threshold of 35% of normal which is regarded as the protective level. Elastase inhibition capacity displayed similar changes (r = 0.85). The sputum concentration of alpha 1-antitrypsin rose more slowly than the plasma concentration; from the initial level (median 8 mg/l) it reached a maximum about four times higher after 24 hours (median 36 mg/l; P less than 0.02). Elastase inhibition capacity rose from 151 mIU/ml (median) before the alpha 1-antitrypsin infusion to 450 mIU/ml at 24 hours. These findings suggest that alpha 1-antitrypsin replacement will have beneficial effects on proteinase-antiproteinase equilibrium. Determination of elastase inhibition capacity in the sputum is suitable for monitoring dosage during replacement therapy.

Detection of lactoferrin in the neutrophils and plasma of the patients suffering from hepatitis C.

Lactoferrin (LF) has antimicrobial properties against bacteria, fungi and several viruses including herpes virus, HIV and hepatitis C virus. The aim of this study was to detect LF in PMNs and plasma of the patients suffering from hepatitis C and the healthy persons. The sonicated solutions of PMNs of two groups were evaluated by SDS-PAGE (10%), isoelectric focusing (30%) and dot blotting. The level of LF in plasma was measured by ELISA. The results confirmed the presence of LF in PMNs of the two groups. ELISA showed that the level of LF in plasma of patients was higher than normal persons. Based on these findings we conclude that not only the production of LF was not reduced in the patients but also its level was significantly increased compared with the normal persons(P less than 0.0001).

Effects of an Enhanced Vitamin A Intake During the Dry Period on Retinoids, Lactoferrin, IGF System, Mammary Gland Epithelial Cell Apoptosis, and Subsequent Lactation in Dairy Cows

Studies in vitro show important interactions among vitamin A, lactoferrin, and insulin-like growth factor (IGF) binding proteins (IGFBP) and, thus, the IGF system. As a consequence, mammary gland epithelial cell proliferation and apoptosis during the bovine dry period and potential milk yield may be affected. We have studied effects of feeding vitamin A (550,000 IU/ d) that exceed daily requirements about 8-fold for up to 2 mo to dairy cows during the dry period on concentrations of retinol and its metabolites in plasma and milk, milk lactoferrin, plasma and milk IGF-I and IGFBP-3, lactoferrin and IGF-I mRNA levels in mammary gland tissue, mammary gland apoptosis, and 100-d milk yield in the ensuing lactation. In the group supplemented with vitamin A, the peripartal decrease of plasma retinol was delayed and attenuated, and colostral retinol plus retinylester concentration was enhanced, but colostral β-carotene concentration decreased. The retinoic acid isomer 9,13-dicis retinoic acid that coeluted with 13-cis retinoic acid, was the predominant circulating retinoic acid and was higher in GrA than the control group. Plasma IGFBP-3 concentrations were positively correlated with plasma retinol concentrations (r=0.51), but there were no group differences. Numbers of apoptotic epithelial cells in mammary epithelium were higher at drying off and parturition than in the middle of the dry period, coinciding with high concentrations of IGF-I and lactoferrin in mammary secretions. At parturition, numbers of apoptotic cells in mammary gland biopsies in cows supplemented with vitamin A were higher than in control cows. In conclusion, supplementation of dairy cows during the dry period with high amounts of vitamin A did not significantly modify concentrations of lactoferrin, IGFBP-3, and IGF-I in plasma and in mammary secretions, but slightly decreased energy-corrected 100-d milk yield and milk fat yield, possibly because of enhanced apoptic rates of mammary cells.

C-Reactive Protein and Antibacterial Activity in Blood Plasma of Colostrum-Fed Calves and the Effect of Lactulose

Several milk proteins are very important for immunological defense and can be absorbed in the intestine of calves in the first hours after birth. The influence of colostrum intake and the effect of additional lactulose application on the concentration of C-reactive protein (CRP) in blood were investigated. The CRP is known as a mediator of innate immunity. Results were compared to the bovine acute phase protein haptoglobin, and to lactalbumin, lactoferrin, and immunoglobulins in plasma from calves. After colostrum intake, the concentration of most proteins were strongly increased. The data show, for the first time, a significant increase of CRP in the blood of calves 1 d after colostrum intake (nonlactulose group, n = 10), and an even more significant increase in CRP concentration (1 d postpartum) was measured in the group of animals with additional application of lactulose (lactulose group, n = 10) when compared to the nonlactulose group. In an in vitro assay with the plasma of these animals, an increased bactericidal activity was detected against Morganella morganii (1 d postpartum) in both groups, but again a higher activity occurred in the lactulose group. The results of these investigations emphasize the importance of colostrum intake during the first hours after birth for the defense potential of newborn calves. In addition, lactulose may have a positive effect in the period of passive transfer of colostrum proteins and in the immune defense.

Purification and quantification of lactoferrin in equine seminal plasma.

Lactoferrin with a molecular mass of 80 kDa was purified from equine seminal plasma by heparin-Agarose affinity chromatography and Sephacryl S-200 gel filtration. Purified lactoferrin was found to be highly homogeneous on the bases of its migration as a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and of the monospecificity of rabbit antibodies to the purified protein in immunoblotting of seminal plasma proteins. A sandwich enzyme-linked immunosorbent assay was developed for quantifying lactoferrin in equine seminal plasma. Seminal plasma lactoferrin concentrations in 23 normal stallions ranged from 42 to 453 microg/ml, with a mean value of 157 +/- 118 microg/ml (S.D.).

Characteristic transport of lactoferrin from the intestinal lumen into the bile via the blood in piglets

Lactoferrin is a major iron-binding protein in milk from several species, such as humans, monkeys, mice and sows. Using neonatal and weaner piglets, the characteristic transfer of lactoferrin from intestinal lumen into bile via the circulation was investigated. Bovine lactoferrin (1 or 3 g/kg body weight) was infused into the stomach through a polyethylene tube or into the duodenum through a duodenal catheter over 5 min. Peripheral blood and bile samples were collected after the infusion. Lactoferrin absorbed into plasma and bile were assayed quantitatively by double-antibody enzyme-linked immunosorbent assay, and homogeneity of bovine lactoferrin in plasma and bile was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting methods. Morphological investigation was carried out according to the peroxidase anti-peroxidase method. Following oral administration in neonatal pigs, bovine lactoferrin appeared in the blood circulation and reached a peak level after 2 h. It was confirmed immunohistochemically that lactoferrin was transported by endocytosis via the epithelial cells. Lactoferrin absorbed into the blood was also detected in the bile and reached a peak value 12 h after oral administration. Transportation of lactoferrin from the intestinal lumen into the bile via the bloodstream was also observed in weaner piglets. Lactoferrin transported into plasma and bile was confirmed to be the same substance as administrated lactoferrin by electrophoresis and immunoblotting methods. Lactoferrin transported into bile was re-absorbed into the blood in neonatal pigs. These results demonstrate that lactoferrin contained in milk is transported into the circulation from the intestinal lumen and excreted into the bile, suggesting the possibility of entero-hepatic circulation of lactoferrin in neonatal pigs.

Within-subject variation of elastase/α1-protease inhibitor complexes and lactoferrin in plasma

Within-subject variation of elastase/α1-protease inhibitor complexes and lactoferrin in plasma

Within-subject variation of elastase/α1-protease inhibitor complexes and lactoferrin in plasma

Several studies have shown increased plasma concentrations of neutrophil elastase in complex with alpha 1-protease inhibitor and/or lactoferrin in inflammatory conditions, and serial measurements have been advocated in order to follow disease activity. However, data on the magnitude of the within-subject variation are necessary for evaluation of the significance of changes in results obtained on analysis of serial samples. Within-subject variation of elastase/alpha 1-protease inhibitor complexes and lactoferrin over a short time was studied in six young men who had blood samples drawn every 4 h over 2 days. Within-subject variation over a longer time was investigated in 12 healthy adults, 6 females and 6 males, who had blood samples drawn in the morning once a week for 10 weeks. From five of the females and five of the males, blood samples were also drawn every morning on 5 consecutive days during 1 week. Within-subject variations over hours, days, and weeks were estimated as 0.050, 0.124, and 0.148 for elastase/alpha 1-protease inhibitor complexes and as 0.101, 0.119, and 0.143 for lactoferrin. A tendency towards variation of LAC with menstrual cycle in fertile females was noticed. From within-subject variation, between-subject variation and analytical variation, indices of individuality were calculated as 1.1 and 1.8 for elastase/alpha 1-protease inhibitor complexes and lactoferrin, respectively. This means that within-subject variation for lactoferrin is quite small compared to between-subject variation, and the usefulness of reference limits is very limited, when interpreting results from individual patients. For elastase/alpha 1-protease inhibitor complexes, the use of reference limits might be more appropriate, although still not optimal.

Lactoferrin Binding Molecules in Human Seminal Plasma1

During ejaculation, the iron binding protein lactoferrin binds to sperm and forms a major component of sperm-coating antigens. Physicochemical properties of lactoferrin in seminal plasma (SP) and on sperm differ from those of purified lactoferrin. These differences have been attributed to the binding of unknown seminal macromolecules to lactoferrin. We have studied lactoferrin binding molecules in SP. The SP samples were coated onto microtiter plates and tested for binding of biotinylated lactoferrin. SP was found to specifically bind biotinylated lactoferrin. This binding was competitively inhibited by coincubation with unlabeled lactoferrin but was not affected by control incubations done with human IgG or transferrin. Lactoferrin binding molecules in SP were biochemically characterized by using SDS-PAGE and ligand blotting. Biotinylated lactoferrin bound to SP molecules of approximately 120, 60 and 30 kDa. No binding was observed with biotinylated transferrin. The presence of molecules that associate with lactoferrin in SP was further studied by using crossed immunoelectrophoresis. Lactoferrin in SP immunoprecipitated as two peaks, one of which corresponded to purified lactoferrin. These results suggest that some lactoferrin molecules in SP are free and that others are associated with lactoferrin binding molecules. Binding of lactoferrin to lactoferrin binding molecules appears to change its physicochemical properties and thus could influence its biologic activity and its affinity to sperm.

Impaired receptor binding and decrease in isoelectric point of lactoferrin after interaction with human monocytes

The iron-binding glycoprotein lactoferrin binds to specific receptors on human monocytes as an initial step implicated in monocytic iron deposition. In this study, the properties of lactoferrin were studied after its interaction with human monocytes. Rebinding of lactoferrin to its monocytic receptor was grossly impaired and a small decrease in isoelectric point from 8.9 to 8.8 was observed. In contrast, antigenic and iron-binding properties of lactoferrin were preserved, the molecular weight by SDS-polyacrylamide gel electrophoresis was unchanged and no low-molecular fragments were detected by gel-filtration. These findings indicate that lactoferrin molecules cannot operate in a cyclic manner to deposit iron. Furthermore, these results might contribute towards explaining the complex disappearance kinetics observed for lactoferrin in plasma.

Lactoferrin in plasma measured by an ELISA technique: evidence that plasma lactoferrin is an indicator of neutrophil turnover and bone marrow activity in acute leukaemia.

This study describes an ELISA technique with high specificity, sensitivity, accuracy and reproducibility for measurements of plasma lactoferrin. The detection limit was 0.001 microgram/ml and the median value obtained in EDTA plasma from 47 healthy adults was 0.100 microgram/ml (0.05 fractile: 0.046 microgram/ml, 0.95 fractile: 0.257 microgram/ml). The lactoferrin concentration in serum was on the average 2 1/2 times higher than in plasma. The ambient temperature did not influence the plasma concentration during the first 6 h from blood sampling to separation of plasma from the cells. In 8 patients with untreated acute leukaemia plasma lactoferrin was positively correlated to the peripheral neutrophil count. An almost parallel course in plasma lactoferrin and peripheral neutrophil number was observed in 4 patients with AML during chemotherapy. In 2 patients achieving complete remission, plasma lactoferrin increased about 6 d before the concomitant increase in neutrophil count, suggesting plasma lactoferrin as an early predictor of bone marrow regeneration.

A rapid and sensitive non-competitive avidin-biotin assay for lactoferrin

We have developed an avidin-biotin assay for the detection of lactoferrin in human seminal plasma. We compared 5 modifications of this assay, and found the non-competitive avidin-biotin assay (NABA) to be the most sensitive. The detection limit of 3-step NABA was 0.2 or 0.1 ng lactoferrin/ml, depending whether avidin-biotin-peroxidase complex (ABC) or avidin-peroxidase was used. The intra-assay and inter-assay coefficients of variation for 3-step NABA were 6.2 and 8.5%, respectively. The lactoferrin levels of human seminal plasma samples measured by 3-step NABA and radioimmunoassay (RIA) showed good correlation ( r = 0.96). The total performance time of 3-step NABA is flexible and the method can be modified for rapid (less than 1 h) or overnight assay according to need.

Lactoferrin receptors in normal and leukaemic human blood cells.

The binding of 125I-lactoferrin to a variety of peripheral blood cells was examined. In the concentration range from 10(-9) mol/l to 10(-6) mol/l a receptor-like binding of lactoferrin was observed in monocytes as well as in polymorphonuclear leucocytes. At the low concentrations of lactoferrin in plasma (about 10(-9) mol/l) the cellular binding to monocytes was about 10 times higher than the binding to polymorphonuclear leucocytes and lymphocytes. A major result from a kinetic analysis was a lower apparent binding affinity to polymorphonuclear leucocytes (KD about 2 X 10(-7) mol/l) than to lymphocytes and monocytes (KD about 2 X 10(-8) mol/l). Studies in leukaemic cells showed that lymphocytes from patients with chronic lymphocytic leukaemia bound lactoferrin to the same small extent as normal lymphocytes. In contrast, a larger component of binding with high affinity (KD about 2 X 10(-8) mol/l) could be demonstrated to lymphoblasts as well as to myeloblasts.