Elevated serum calprotectin levels in HIV-infected patients: the calprotectin response during ZDV treatment is associated with clinical events.

The calcium-binding myelomonocytic protein calprotectin (L1 protein) was quantified in serum from 51 patients with HIV infection and in 20 HIV-seronegative blood donors. Significantly elevated levels were found both in asymptomatic patients and in people with AIDS compared with controls. The calprotectin level was not related to ongoing or recent opportunistic infections. For patients with CD4+ counts above 50 x 10(6)/L, a significant negative correlation was found between serum calprotectin levels and the CD4+ counts. Serial samples from 24 patients during their first year of zidovudine (ZDV) treatment showed a further elevation of serum calprotectin during the first months of ZDV treatment, with a subsequent decline to pretreatment levels. A low calprotectin response during the first 6 months, determined as area under the curve, was associated with the occurrence of at least one AIDS-defining infection during the first year of antiviral treatment. Also, a low calprotectin maximal response during ZDV therapy was associated with short survival. Similar associations were not found for neopterin, beta 2-microglobulin, HIV p24 antigen, or CD4+ or CD8+ lymphocytes in blood. Our findings in a limited number of patients suggest that calprotectin levels may reflect immune activation and other immune mechanisms correlated with enhanced antimicrobial defense induced at least transiently by antiviral treatment.

Quantitation of a highly immunogenic leukocyte antigen (L1) by radioimmunoassay: methodological evaluation.

This paper describes a radioimmunoassay (RIA) for the quantitation of a major protein antigen (L1) released from human granulocytes. A protein A-carrying strain of Staphylococcus aureus was used as a solid phase IgG-binding reagent for the separation of antigen-antibody complexes from free antigen in the assay. A two-step version of the RIA may be completed in 2.5 h and has a detection limit of about 5 ng/ml. The sensitivity may be increased by minor modifications. A single step version takes 1.5 h and has adequate sensitivity to cover clinically important plasma levels. Selection and optimal use of reagents for the two-step procedure is described and their storage discussed. The simplicity of the procedure combined with high sensitivity and satisfactory accuracy, precision and reproducibility makes this assay suitable for quantitation of L1 in various body fluids.

Radiation-induced granulocyte transmigration predicts development of delayed structural changes in rat intestine.

We examined whether early radiation-induced granulocyte transmigration (assessed by the fecal transferrin excretion ELISA assay) predicts subsequent development of (consequential) chronic radiation enteropathy. After accounting for the effect of radiation dose, transferrin excretion remained an independent predictor of overall tissue injury, intestinal fibrosis, and mucosal ulcers, but not TGF-beta immunoreactivity.

Effects of calprotectin in avridine-induced arthritis.

Plasma levels of calprotectin correlate with disease activity and clinical assessments of arthritis in various rheumatic diseases, and high levels have been demonstrated in the synovial fluid of patients with rheumatoid arthritis. However, the role of calprotectin in rheumatic inflammation is unclear. The purpose of the present study was to investigate potential intra-articular effects of calprotectin. Calprotectin was injected into joints of healthy male Lewis rats and into joints of rats in the latency period before onset of avridine-induced arthritis. In addition, a group of animals had IgG antibodies to rat calprotectin injected into joints before onset of avridine-induced arthritis. Injection of 0.2 or 10 micrograms calprotectin into the ankles of healthy male Lewis rats resulted in histologically minor and reversible inflammatory changes, but without any circulating antibodies to calprotectin. Furthermore, animals with 40 micrograms calprotectin injected into ankles before the expected onset of avridine-induced arthritis had lower scores for cellular infiltration than were seen in control joints. This difference did not quite reach statistical significance in the two-sided test used. However, the induced arthritis increased in joints injected with IgG antibodies to calprotectin. These findings may indicate that increased local concentrations of calprotectin are partially protective against avridine-induced arthritis. In contrast, reduced local concentrations appear to exacerbate the severity of arthritis. Calprotectin may thus be involved in the regulation of inflammatory processes in joints.

Distribution of a formalin-resistant myelomonocytic antigen (L1) in human tissues. I. Comparison with other leukocyte markers by paired immunofluorescence and immunoenzyme staining.

L1 is an approximately 36-kd protein recently identified as a cytoplasmic and surface marker antigen of virtually all resting peripheral blood neutrophils and monocytes. This study of its tissue distribution showed that L1 is particularly well preserved in formalin-fixed and paraffin-embedded routine material. It had a restricted distribution within the monocyte-derived cell lineage, being mainly confined to reactive histiocytes (infiltrating macrophages). L1 was a much more reliable marker for such cells than lysozyme, except that the latter was better expressed by epithelioid and giant cells. L1 was lacking in HLA-DR-positive interdigitating, Langerhans', and most intestinal histiocytic cells. The same was true for Kupffer cells in normal livers; but in livers of three patients with malignant histiocytosis or histiocytic medullary reticulosis infiltrating histiocytes and putative Kupffer cells stained positively. Follicular dendritic cells and tangible body macrophages were always questionably L1 positive.

Distribution of a formalin-resistant myelomonocytic antigen (L1) in human tissues. II. Normal and aberrant occurrence in various epithelia.

L1 is an approximately 36-kd protein present in virtually all resting peripheral blood neutrophils and monocytes. It is particularly well preserved in formalin-fixed and paraffin-embedded routine material. In a recent immunohistochemical study, the authors showed that L1 has a restricted distribution within the monocyte-derived cell lineage, being mainly confined to reactive histiocytes (infiltrating macrophages). A protein sharing physicochemical and antigenic properties with L1 was identified in extracts of epidermal scales obtained from patients with psoriasis. This epithelial L1 was generally not expressed by normal epidermis, but its production was abundant in several skin diseases. Moreover, mucosal squamous epithelium normally expressed L1. No other epithelia showed signs of L1 production, although occasional patchy uptake was indicated, particularly in kidney tubular epithelium.

Distribution of a new myelomonocytic antigen (L1) in human peripheral blood leukocytes. Immunofluorescence and immunoperoxidase staining features in comparison with lysozyme and lactoferrin.

The L1 antigen is a highly immunogenic protein of about 36,500 daltons that can be purified from granulocytes with good yield. Immunocytochemistry with a rabbit anti-serum raised against L1 showed it to be present in the cytoplasm of virtually all resting peripheral neutrophils and monocytes. Moreover, immunofluorescence staining demonstrated variable expression of L1 on the plasma membrane of both these cell types, usually along with lysozyme. This indicated that L1 represents a secretory product like lysozyme as their coexpression on the surface of vital cells was contrasted by the absence of lactoferrin. Cytoplasmic L1 was well preserved by both precipitating and cross-linking fixatives, the latter being preferable to avoid leaching out of antigenic material and to obtain good cellular morphology. Thus, fixation for 3 minutes at room temperature in glutaraldehyde (1%)-formaldehyde (3%) afforded excellent immunoperoxidase staining, particularly when a calcium-containing buffer was used. L1 was not found in eosinophilic granulocytes or in resting B- and T-lymphocytes. Neither did blast transformation of lymphocytes seem to induce L1 expression.

Mac 387 antibody and detection of formalin resistant myelomonocytic L1 antigen.

The murine monoclonal antibody Mac 387 was raised against a purified protein fraction obtained from human monocytes. By immunoblotting experiments, Mac 387 was shown to react with a previously defined antigen called L1; this is a multichain myelomoncytic protein of about 36 Kd which shows sequence homology with the cystic fibrosis antigen. The L1 protein is present in the cytoplasm of virtually all resting peripheral neutrophils and monocytes; it is also variably expressed on the plasma membrane of these cells, possibly as a secretory product. Because the L1 antigen is resistant to denaturation by formalin, its tissue distribution can be studied in routinely processed biopsy material. In a wide variety of specimens Mac 387 was shown by immunohistochemical analysis, to produce a cytoplasmic staining pattern concordant with that of a well defined polyclonal antibody to the L1 antigen. Cytoplasmic reactivity was obtained with granulocytes and infiltrating macrophages but generally not with several categories of dendritic cells. In addition, squamous epithelium of mucous membranes was strongly positive, in contrast to normal epidermis.

Calprotectin and complement activation during major operations with or without cardiopulmonary bypass.

Plasma concentrations of the granulocyte cell marker calprotectin were assessed during operation and 24 hours postoperatively in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass, abdominal aneurysmectomy with implantation of an aortic graft, or thoracotomy without implantation of synthetic material. The concentration of calprotectin increased significantly (p < 0.01) in all three groups. Ten of the 30 patients in the group undergoing cardiopulmonary bypass received methylprednisolone at the start of the operation. No difference in calprotectin concentration was seen between the two subgroups (p > 0.05). Plasma concentration of calprotectin was shown to increase rapidly in patients undergoing cardiopulmonary bypass and aneurysmectomy, in whom complement activation also took place. However, the calprotectin concentration increased slowly during the operation and the postoperative period in patients undergoing a thoracotomy, in whom complement was not activated. At wound closure the calprotectin concentration was significantly elevated in the cardiopulmonary bypass and aneurysmectomy groups compared with the thoracotomy group (p < 0.05). The calprotectin concentration remained elevated during the postoperative period in all three groups. Our results indicate that calprotectin may serve as a suitable cellular marker when the biocompatibility of artificial surfaces is studied.

Reduced complement and granulocyte activation with heparin-coated cardiopulmonary bypass.

Plasma concentrations of the complement activation products C3b, iC3b, and C3c; the terminal C5b-9 complement complex; and the granulocyte proteins calprotectin, myeloperoxidase, and lactoferrin were assessed in two groups of patients undergoing aortocoronary bypass procedures. In 10 patients operated on, the bypass circuits were coated by the Carmeda Bio-Active Surface and systemic heparinization was reduced to 1.5 mg/kg; in another 10, the systems were uncoated and the dosage of systemic heparinization was 4 mg/kg. In both groups, significant complement activation was observed after the onset of cardiopulmonary bypass, but the maximum levels of C3b, iC3b, and C3c and the terminal C5b-9 complement complex were significantly lower in the heparin-coated group. In both groups, a significant increase in calprotectin, myeloperoxidase, and lactoferrin release was observed by the end of operation. The maximum myeloperoxidase levels were significantly lower in the heparin-coated group than those in the uncoated group (p = 0.03). There was a correlation of borderline significance between the formation of terminal C5b-9 complement complex and lactoferrin release, as well as between the formation of terminal C5b-9 complement complex and myeloperoxidase release (p = 0.05). The postoperative blood loss did not differ significantly between the two groups. We conclude that coating by end point-attached and functionally active heparin allows a significant reduction in the amount of systemic heparinization, and significantly reduces complement and granulocyte activation.

Contaminating fibrin in CPD-blood: solubility in plasma and distribution in blood components following separation.

In order to estimate the solubility of contaminating fibrin in CPD-blood, thrombin induced fibrin polymerzation in CPD-plasma was examined by light scattering and fibrinopeptide A (FPA) determinations. In addition, I125 fibrin monomer enriched CPD-blood was used to investigate fibrin monomer retention in blood bags and transfusion filters (170 microns) and fibrin distribution in blood components derived from CPD-blood. Initial fibrin polymerization in CPD-blood occurred after conversion of 15 per cent of the fibrinogen to fibrin, implying that substantial amounts of fibrin may be kept solubilized in CPD-blood bags. Only minor amounts of I125 fibrin monomers were retained in blood bags (2.4 per cent) and in transfusion filters (2.9 per cent) after sham transfusions. After separating I125-fibrin monomer enriched CPD-blood into its constituent components, the major part of fibrin (75.0 per cent) could be traced in the cryoprecipitate.

ANCA against bactericidal/permeability-increasing protein, azurocidin, calprotectin and defensins in rheumatic and infectious diseases: prevalence and clinical associations.

OBJECTIVE: To determine the prevalence and clinical associations of ANCA against the antibiotic proteins and peptides: Bactericidal/permeability-increasing protein (BPI), Azurocidin (AZ), Calprotectin (CP) and beta-Defensin-1 and -2 (DF). METHODS: Patients with ANCA-associated vasculitides (n = 99), other vasculitides and rheumatic connective tissue diseases (n = 303), HIV-infection (n = 66), other infectious diseases (n = 134) Crohn's disease (n = 12) and ulcerative colitis (n = 12) were tested for BPI-, AZ-, CP-, DF-, PR3-, and MPO-ANCA in indirect immunofluorescence technique (IFT) and ELISA. RESULTS: In ANCA associated vasculitides BPI-ANCA were detected in 6% of patients. In HIV infection, BPI was the main target antigen of ANCA-IFT positive sera (74%). BPI-ANCA was associated with higher inflammatory activity. In Crohn's disease and ulcerative colitis BPI-ANCA was prominent (34% of patients). AZ-ANCA were found in 5% of patients. No ANCA were detected against defensin and calprotectin. CONCLUSION: BPI-ANCA is the main autoantibody in HIV and is associated with higher inflammatory activity. In inflammatory bowel diseases BPI-ANCA is predominant, AZ-ANCA are also present to a lesser extend. Both were not useful characterize clinical subgroups. No ANCA were detected against calprotectin or defensins.

Cardiac surgery and distribution of the leukocyte L1 protein-calprotectin.

Activated polymorphonuclear leukocytes (PMN) secrete lysosomal enzymes, eicosanoids and toxic oxygen metabolites. In cardiac surgery patients, we measured arterial plasma levels of PMN and L1 (calprotectin), a prominent granulocyte protein, during cardiopulmonary bypass (CPB). The myocardial arterio-venous gradients were evaluated during reperfusion after cold cardioplegic arrest (n = 10). The arterial plasma concentration of L1 increased during CPB from 344 +/- 71 micrograms/l (mean +/- SD) preoperatively to 5221 +/- 1267 micrograms/l at the end of CPB (P less than 0.001). Simultaneously, the number of circulating PMN also increased (from 4.4 +/- 0.4 x 10(9)/l to 9.1 +/- 1.2 x 10(9)/l (P less than 0.05)). There was a positive correlation between the mean number of circulating PMN and the plasma level of L1 at all sampling times during CPB (r = 0.93, P less than 0.05). A coronary sequestration of both L1 (P less than 0.006) and PMN (P less than 0.002) was found after 5 min reperfusion. This was not present at 15 and 30 min reperfusion. The coronary entrapment of L1 and PMN did not covary significantly, and was unrelated to both the time of cardioplegic arrest and the arterial levels of L1 and PMN. In conclusion, the increased plasma concentrations of PMN and L1 during CPB and the coronary sequestration of both PMN and L1 may be factors in the pathogenesis of reperfusion injury of the myocardium.

Decreased Fc-receptor binding in human monocytes exposed to ethanol in vitro.

Human blood monocytes were incubated with or without ethanol (14 mM-220 mM, initial concentration) in non-sealed wells in an atmosphere of 5% CO2 in air for various time periods. The actual ethanol concentration was assayed in the media at the beginning and at the end of each incubation period. No change in ethanol content was found after 5 or 15 min incubation, while a reduction to about 70% of the initial concentration was observed after 6 hr incubation. Binding of IgG-opsonized particles to the Fc-receptors was tested after ethanol exposure of the cells. An initial concentration of 14 or 28 mM ethanol caused no difference from controls, neither did incubation in 55 mM ethanol for 5 min. Monocyte incubated in 55 mM ethanol for 15 min showed reduced binding of particles, and further reduction was obtained by increasing the ethanol concentration. Six hr incubation in 55 mM ethanol caused no further reduction in binding capacity. Reduced binding of test particles to Fc-receptors after ethanol incubation was demonstrated with variable amounts of test particles, as well as variable length of the binding assay period. There was no change in viability, morphology or spreading ability of the monocytes after ethanol treatment.

The leucocyte protein L1 (calprotectin): a putative nonspecific defence factor at epithelial surfaces.

The L1 protein occurs at high concentrations in neutrophils, monocytes, certain reactive tissue macrophages, squamous mucosal epithelia, and reactive epidermis. It constitutes in fact about 60% of the neutrophilic cytosol protein fraction. The two L1 chains (L1H and L1L) are referred to by a bewildering collection of names, various authors having different preferences (MRP-8 and MRP-14; CFA or calgranulin A and B). The most recent proposal is calprotectin because of its calcium-binding properties and antimicrobial effect shown in vitro. L1 belongs to the S-100 protein family and may be involved in the regulation of keratinocyte proliferation and differentiation. It exists at high levels in blood and interstitial tissue fluid in several infectious, inflammatory, and malignant disorders, and it is released abundantly in foci of granulocytes and macrophages. The C-terminal sequence of the L1H chain has been shown to be identical to the N-terminus of peptides known as neutrophil immobilizing factors. Such an activity of L1 could be important for the accumulation of vital granulocytes, while L1 released from neutrophils, macrophages and epithelial cells might exert antimicrobial activity, perhaps by depriving microorganisms of zinc. The minimum inhibitory concentrations of L1 in vitro were found to be 4-32 mg/l for Candida albicans, 64 mg/l for Staphylococcus aureus, 64-256 mg/l for S. epidermidis, and 256 mg/ml for Escherichia coli and Klebsiella spp. Killing was observed at 2-4 times higher concentrations. In patients with HIV infection, those who developed oral candidiasis had significantly lower parotid L1 levels than those who did not (67 micrograms/l vs. 216 micrograms/l).

[Plasma calprotectin. A new prognostic marker of survival in alcoholic liver cirrhosis]. / Plasmacalprotektin. En ny prognostisk markør for overlevelse ved alkoholisk levercirrose.

The purpose of this study was to determine plasma concentrations of calprotectin in patients with different severity of alcoholic cirrhosis. Additionally, the prognostic value of calprotectin for recurrent infections and for survival was investigated after a median observation period of 19 months. No difference was found in calprotectin levels when comparing healthy controls (n = 16), compensated (n = 50) and decompensated cirrhotics (n = 34). However, high calprotectin concentrations (> median) was a significant prognostic marker of poor survival (p = 0.001, Log-rank test). Calprotectin levels (> median) showed an independent and much higher prognostic value than variables of liver disease (multivariate Cox model). During follow-up calprotectin levels (> median) were also a predictor of recurrent infection (p = 0.009, Log-rank test). Thus, in patients with alcoholic cirrhosis, plasma calprotectin appears to be a new prognostic marker of survival, which seems independent of severity of liver disease. Furthermore, high plasma calprotectin levels may characterize a group of cirrhotics with recurring bacterial infections.

Quantification of S100A12 (EN-RAGE) in blood varies with sampling method, calcium and heparin.

S100A12 is a calcium-binding protein predominantly found in neutrophil granulocytes and monocytes. Its usefulness in monitoring inflammatory disease states depends on documentation that assay results are reliable. This study aimed at defining guidelines for blood sampling, selection of optimal material handling and reference intervals in healthy controls while taking into account the basic features of S100A12. An enzyme linked immunosorbent assay was developed based upon antibodies induced in rabbits by injection of recombinant S100A12. Our studies confirm that oligomers of S100A12 are generated in the presence of calcium. Structural changes in S100A12 mediated by calcium influence the interaction with antibody. This is proposed as the background for our very low readings of S100A12 in Ethylene Diamine Tetraacetic Acid (EDTA) plasma. Individual S100A12 levels did not change substantially over a 5-week sampling period. Based upon testing of 150 blood donors we suggest reference intervals of S100A12 in serum to be 49-1340 microg/l for women and 27-1750 microg/l for men. The estimated mean concentrations were 234 microg/l in serum samples (range 12-15791), 114 microg/l (range 3-17282) in re-calcified EDTA plasma and 48 microg/l (range 2-14843) in heparin plasma. Without adding calcium to EDTA plasma before running the assay, concentrations were around 2 microg/l (16 persons). S100A12 quantification is assumed to become relevant for diagnostic use in many disease states. The importance of the handling and analysing conditions for a reliable result was examined. We recommend serum collected in gel-containing tubes as the preferred sample material and have suggested reference intervals for healthy individuals.