Niels Ebbe Hansen

Receptor binding of lactoferrin by human monocytes

Summary. The binding of iron‐saturated 125I‐lactoferrin to human monocytes was studied at pH 7·4 and 37°C. Monocytes in suspension bound 125I‐lactoferrin by a reversible, saturable and specific binding indicating the presence of a receptor. The dissociation constant (KD) of the binding was estimated at about 4·5 × 10−9 M and the number of receptors was about 1·6 × 106 per monocyte. The affinity of native lactoferrin (20% iron saturated) was only slightly below that of iron‐saturated lactoferrin (KD about 7·9 × 10−9 M). Human transferrin, horse cytochrome c and human immunoglobulin G were without inhibitory effect on the binding of 125I‐lactoferrin. The majority of cell‐bound 125I‐lactoferrin was dissociable. The dissociation rate was not affected by addition of unlabelled lactoferrin to the dissociation medium. The binding of 125I‐lactoferrin to adherent mononuclear blood cells showed an about 100‐fold lower affinity (KD about 2·5 × 10−7 M) than to cells in suspension, but the specificity of the binding was the same. These results are compatible with the idea that lactoferrin exerts a biological effect mediated by an interaction with cells of the monocyte/macrophage lineage.

Lysozyme turnover in man.

Lysozyme turnover studies with (125)I-labeled human lysozyme were carried out on 22 patients, viz. nine control patients, seven nephrological patients with varying degrees of renal insufficiency, including three bilaterally nephrectomized patients, and six hematological patients with disturbed turnover of the neutrophilic granulocytes. It was found that plasma lysozyme has a rapid turnover with a fractional catabolic rate of 76%/hr of the plasma content. Lysozyme catabolism varied with the endogenous creatinine clearance; in addition however, extrarenal sites of catabolism were demonstrated since lysozyme could be broken down in the anephric patients, although only at a rate amounting to about 15% of the rate found in persons with intact kidneys. In the uremic patients the increased plasma lysozyme concentration was due to decreased rates of catabolism; in the hematological patients the increased plasma lysozyme level was due to increased rates of synthesis which supports the hypothesis that plasma lysozyme mainly stems from disintegrating neutrophilic granulocytes. Furthermore, it was shown that in the nonhematological patients examined, the rate of synthesis varied with the endogenous creatinine clearance.

Chromosomes and survival in multiple myeloma. A banding study of 25 cases

Abstract The chromosomal findings in 25 cases of multiple myeloma are reported. The chromosomes were directly prepared from bone marrow cells and studied by trypsin-Leishman banding. Abnormal stem lines were found in 16 cases (64%), and were characterized by banding in 12 cases. Twelve cases were hyperdiploid; 11 cases carried marker chromosomes, 50% of which involved chromosome No. 1. Five cases were trisomic for 1q21-1q3. A vulnerable point was located on 3q27 or 28 or 29. The two cases that carried the 14q+ marker chromosome were also the only cases with plasma cells in the peripheral blood. Based on this study and the literature it is suggested that a 14q+ is necessary for the development of plasma cell leukemia. The actuarial survival curves gave no evidence for major prognostic significance of the demonstration of an abnormal cell clone. Trisomy for 1q21-1q3 may be a bad prognostic sign. The results are discussed with special reference to the aberrations in acute nonlymphocytic leukemia as reported earlier in a series of 88 cases from this laboratory.

Lysozyme Activity in Human Neutrophilic Granulocytes

Summary. Among five different methods for the extraction of lysozyme from human neutrophilic granulocytes (mechanical disruption, freezing‐thawing, sonication, solubilization with saponin and with n‐butanol), extraction with n‐butanol was found to give the highest lysozyme yield per cell. With this method the lysozyme content of neutrophilic granulocytes was measured in a control group with no haematological, renal or infectious disease, and in patients with bacterial infection, severe uraemia, and myeloproliferative disorders.

Lactoferrin‐mediated transfer of iron to intracellular ferritin in human monocytes

Interactions of 125I‐59Fe‐lactoferrin with human monocytes were studied. After 4 hours of incubation, the uptake of 59Fe exceeded that of 125I. In dissociation studies the cellular 59Fe‐activity was only partly dissociable during 16 h, whereas the 125I‐activity could be released nearly completely. Disruption of the cells and studies on the cytosolic phase were performed employing gel‐filtration and affinity chromatography. An appreciable amount of lactoferrin was found in the cytosolic phase. About 50% of the cytosolic 59Fe‐activity was bound to ferritin. The results suggest that lactoferrin is internalized into monocytes and that iron is transferred to ferritin. These cellular events may contribute to an understanding of the accumulation of iron in the monocyte/macrophage system observed during inflammatory conditions.

Lysozyme turnover in the rat

Lysozyme turnover in the rat was studied with (125)I-labeled rat lysozyme. It was found that plasma lysozyme has a rapid disappearance rate with a half-life of 75 min. The rate of synthesis was calculated at 3.4 mug/min per 100 g rat. This rate of synthesis was compared with figures from the literature for the turnover rate of neutrophilic granulocytes, and the data were consistent with the concept that disintegrating neutrophils are the main source of plasma lysozyme. The distribution of enzymatic lysozyme activity and of radioactive lysozyme was studied in several organs. Very high enzymatic activity was found in leukocytes as were considerable activities in lungs, kidneys, bone marrow, spleen, and intestine; little enzymatic activity was found in the urine. High radioactive levels as compared with plasma radioactivity were demonstrated only in the kidneys. This indicates that of the organs studied, the kidney is the predominant site of storage and destruction of plasma lysozyme. Lysozyme was found to disappear only slowly from the kidneys over a period of 4 days. The data obtained seem to indicate that lysozyme or a lysozyme degradation product precipitable by trichloroacetic acid was released in small amounts from the kidneys to plasma throughout this period.

Different membrane expression of CD11b and CD 14 on blood neutrophils following in vivo administration of myeloid growth factors

Summary. During the administration of recombinant human granulocyte colony‐stimulating factor (rhG‐CSF) or granulocyte‐macrophage CSF (rhGM‐CSF) we studied the early and late changes of membrane antigen density on neutrophils. RhG‐CSF and rhGM‐CSF both caused an early transient reduction in blood neutrophilic granulocyte‐concentration within the first 30 min after treatment followed by a marked later increase during the subsequent 24 h. During the early neutropenia quantitative flow cytometry showed an associated marked increase in the density of membrane CD11b from 169 × 103 before to 568 × 103 A.U. per cell induced by rhGM‐CSF but a non‐significant change by rhG‐CSF, suggesting that different mechanisms may be responsible for the transient neutropenia. The subsequent neutrophil granulocytosis was followed by a significantly (P<0.05) increased density of the CD14 antigen from 6.1 × 103 before to 15.9 × 103 A.U. per cell during treatment with rhG‐CSF. but not by rhGM‐CSF administration.

The Relationship between the Turnover Rate of Neutrophilic Granulocytes and. Plasma Lysozyme Levels

Summary. Thirty‐six kinetic studies with radioactive diisopropylfluoro‐phosphate (DF32P) labelled neutrophilic granulocytes were carried out in 33 patients with a wide range of neutrophil counts, and the kinetic data compared with plasma lysozyme levels. A highly significant correlation was found between the neutrophil turnover rate and plasma lysozyme, which suggests that plasma lysozyme is mainly derived from disintegrating neutrophilic granulocytes. Recovery calculations showed, however, that in patients with normal and increased neutrophil counts at least 40% of the neutrophils passing through the blood did not deliver their lysozyme content back to the plasma, probably due to either lysozyme degradation in the tissues and/or due to loss of intact neutrophils from the organism, e.g. to the alimentary tract. The high degree of correlation between the neutrophil turnover rate and plasma lysozyme levels makes it possible, with certain provisos, to use plasma lysozyme levels in the clinical assessment of the neutrophil turnover rate.

LYSOZYME ACTIVITY IN CEREBROSPINAL FLUID

Lysozyme activity was measured in cerebrospinal fluid (CSF) from 114 patients with inflammatory (bacterial and serous meningitis, poly‐radiculitis, encephalitis) and non‐inflammatory (multiple sclerosis, CNS tumors, cerebral vascular diseases) CNS diseases. Highly elevated values were found consistently in patients with bacterial meningitis. Elevated values were found also in patients with encephalitis, poly‐radiculitis, multiple sclerosis and CNS tumors, but a considerable overlapping between these groups and normal controls precludes the use of CSF lysozyme measurements as a diagnostic aid in the latter disease groups. Simultaneous measurements of lysozyme, albumin and IgG in CSF and serum suggested that the mechanism for increased CSF lysozyme values in bacterial meningitis is mainly a breakdown of the blood/brain barrier, whereas the increased CSF lysozyme values in the remaining groups of patients are more likely caused by production of lysozyme by cells within the meninges (neutrophilic granulocytes, monocytes?).

The bone-marrow infiltration pattern in B-cell chronic lymphocytic leukemia is not an important prognostic factor

Abstract:  In a multicentre study of 635 consecutive newly diagnosed patients with B‐CLL, the histological bone marrow (BM) specimens were reviewed independently by each of 3 pathologists and found evaluable for BM infiltration pattern in 575 patients, 404 of whom had a CD5+, mainly FMC7–, faint surface‐membrane immunoglobulin (SIg) fluorescence‐intensity phenotype. In these 404 patients the following BM infiltration patterns were found: mixed nodular‐interstitial (30%), moderate interstitial (44%), heavy interstitial (20%) and diffuse packed (6%). In univariate survival analysis, significant differences were found according to BM pattern (p < 0.05), the presence of nodules being a favorable prognostic sign. In multivariate survival analysis in a model including age, clinical stage, BM pattern, BM lymphocytosis, WBC and sex, only age and stage but not BM pattern or BM lymphocytosis had independent prognostic significance. In stage A, progression‐free survival was significantly longer in patients with nodular than in patients with non‐nodular bone‐marrow pattern. The overall survival of these patients, however, did not differ, possibly owing to the prompt and prolonged treatment given to most patients at the time of progression to stage B or C. We conclude that in CD5+, SIgfaint, mainly FMC7– B‐CLL, bone‐marrow histology may predict unstable disease in early clinical stage but is not important for treatment decisions, when these are based on clinical stage.