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U Persson

Publications and source records attributed to U Persson.

At least 73 records · Page 4Linked to original sources
PubMed1990

HLA-DP incompatibilities induce significant proliferation in primary mixed lymphocyte cultures in HLA-A, -B, -DR and -DQ compatible individuals: implications for allogeneic bone marrow transplantation.

The major part of the proliferative response in primary mixed lymphocyte cultures (MLC) is caused by HLA-DRB1 incompatibilities. In DRB1-matched pairs the proliferation induced by HLA-DRB3, -DQ and -DP mismatches may be unmasked. In most previous studies the influence of HLA-DP incompatibilities in primary MLC has been investigated in homozygous typing cells representing only a few Dw specificities. We were interested in determining the stimulatory capacity of isolated HLA-DP mismatches, ascertained by RFLP analysis, in primary MLC in HLA-A, -B, -DR and -DQ compatible, unrelated heterozygous individuals of many different Dw specificities. Thirty-eight MLCs performed with cells from related pairs and 67 with cells from unrelated pairs were evaluated. All but nine of the MLCs were analyzed in both directions, giving a total of 201 investigated reactions. The relative responses (RR) in the three MLCs performed between DP incompatible, related pairs were all positive (RR greater than or equal to 8%). Eighty of 82 MLCs performed with cells from DP incompatible, unrelated individuals were positive, whereas 37 of 46 MLCs between DP compatible, unrelated pairs were negative (RR less than 8%) (p less than 10(-10)). The magnitude of the RR was influenced by the number of DP mismatches. Thus, the mean RR was approximately twice as high in MLCs in which responder and stimulator cells differed by two DP antigens (mean RR 60.5%) compared with reactions with only one DP mismatch (mean RR 35.4%) (p less than 10(-3)). RFLP-defined HLA-DP incompatibilities predict a positive primary MLC in HLA-A, -B, -DR and -DQ matched individuals with a high degree of accuracy (98%).(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Marrow Transplantation↗
PubMed1990

Leukotrienes stimulate neutrophil adhesion to mesangial cells: modulation with lipoxins.

We have examined polymorphonuclear neutrophil (PMN) adhesion to mesangial cells (MC) in vitro and have assessed the actions of lipoxygenase (LO) products in this process. On exposure to either leukotriene B4 (LTB4), or leukotriene D4 (LTD4), 111In-labeled PMNs adhere to monolayers of cultured MC. These actions were rapid in onset (less than 5 min) and dependent upon leukotriene concentration (10(-9) to 10(-6) M) and the presence of divalent cations. Adhesion was sustained (0-30 min), and neither LTB4 nor LTD4 was metabolized to inactive products during PMN-MC interaction, as determined by their recovery after reverse-phase high-performance liquid chromatography. LTB4 was a PMN-directed stimulus, whereas LTD4 appeared to act on MC. A monoclonal antibody (TS 1/18) against the CD18 component of the PMN CD18/CD11 adhesion complex inhibited the LTB4-induced response, indicating involvement of this PMN glycoprotein in the adhesion process. In contrast, this antibody did not affect LTD4-induced adhesion, suggesting that this response was mediated by other adhesion epitopes. When added alone, neither lipoxin A4 (LXA4) nor lipoxin B4 (LXB4) provoked PMN adhesion to MC. In contrast, LXA4 and LXB4 at equimolar concentrations attenuated the LTD4- but not LTB4-induced response. Together, these results provide further evidence that LO-derived eicosanoids may constitute important early signals that regulate PMN-MC interaction in glomerular inflammation.

Cell Adhesion↗
PubMed1990

The cost-effectiveness of prevention of post-operative thromboembolism.

In recent years, value for money in health care has become of increasing concern. There are various ways to perform an economic evaluation, the most simple being a cost-effectiveness analysis, where differences in costs will influence the choice between methods. Cost-utility and cost-benefit analyses represent more advanced forms of economic evaluations. In this cost-effectiveness analysis, the following three strategies aimed at solving the problem of post-operative thromboembolic complications were compared: (a) no prophylaxis but treatment of occurring complications, (b) general prophylaxis with low-dose heparin for patients over 40 years of age and (c) selective treatment based on post-operative surveillance with a fibrinogen uptake test. Moreover, these alternatives were evaluated for three types of surgery: general abdominal surgery, cholecystectomy and elective hip surgery. Costs for thromboembolic and haemorrhagic complications were estimated from data available for patients hospitalized in Malmö. A sensitivity analysis was made with regard to the frequency of thrombosis, prophylactic effect and treatment costs. Health care costs would be minimized with general prophylaxis in hip and general surgery, whereas no prophylaxis is the most cost-effective alternative in cholecystectomy patients, i.e. with a frequency of thrombosis below 8%. General prophylaxis minimized the duration of patients' health losses due to thromboembolic disease in general, as well as in elective hip surgery. After cholecystectomy, no difference in health loss for the individual was found between the alternative of no prophylaxis and general prophylaxis. Selective treatment was always the least satisfactory alternative in all categories and always the most expensive.

Cost-Benefit Analysis↗
PubMed1990

Avoiding splenectomy in the treatment of children with splenic injury.

Ninety-two consecutive patients with traumatic rupture of the spleen were studied. Of the first 46 children (group A), 44 underwent splenectomy. In the subsequent group (group B) non-operative management was successful in 40 of 46 patients, five patients were operated with splenic repair, and one had the spleen removed. All the ruptures were caused by blunt trauma and the severity of the splenic injury was roughly the same in the two groups of patients. A third of the patients in each group had associated injuries, renal injury being the most common intraabdominal lesion. The median hospital stay was 8.0 days (range 5 to 28) in group A and 12.5 days (range 7 to 18) in group B. Among the 40 patients who were treated conservatively, a biphasic course was seen in 23: one or two days after the accident a period of increased pulse rate, fever and increased abdominal tenderness and pain followed, but no evidence for a delayed rupture was found. Our results of conservative treatment of splenic rupture are encouraging and show that non-operative management should be considered in most cases.

Adolescent↗
PubMed1989

Improved cell depletion in a panning technique using covalent binding of immunoglobulins to surface modified polystyrene dishes.

A method for the chemical modification of plastic surfaces permits covalent binding of proteins and we have used this method in the development of an efficient panning technique. Thus, human peripheral T lymphocytes coated with mouse monoclonal antibodies directed against the CD4 marker may be selectively and reproducibly removed from a lymphocyte population by a short incubation in modified plastic dishes coated with rabbit anti-mouse IgG antibody. Due to the higher protein binding capacity of the dishes the use of the IgG fraction of the coating antibody was sufficient for optimal and reproducible results. In contrast, control dishes with passively adsorbed antibody required an affinity-purified fraction and even then were less efficient.

CD4-Positive T-Lymphocytes↗
PubMed1989

Interleukin 4 induces synthesis of IgE and IgG4 in human B cells.

Interleukin (IL)4 has been shown to regulate the IgG subclasses and induce IgE production in splenic mouse B cells. Here we show that IL4 and phorbol 12-myristate 13-acetate (PMA) induce, on a per cell basis, very high IgE secretion in purified human B cells by using a mouse thymoma (EL4) co-culture method. In addition, a marked increase in the number of IgG4-producing cells was also observed. Furthermore, IL2 could synergize with IL4 and PMA in the production of IgE. By using limiting dilution analysis, a considerable increase in the precursor frequency for IgE was found when IL4 and PMA were added to cultures as compared to cultures with PMA only. This indicates that IL4 induces an isotype switch in human B cells.

Antibody Formation↗
PubMed1989

Recombinant protein A of non-staphylococcal origin is not mitogenic for human peripheral lymphocytes. Mitogenicity of natural protein A is caused by a contaminant.

Recombinant protein A(SpA) produced in Escherichia coli or Bacillus subtilis bacteria did not induce activation of human peripheral mononuclear cells, whereas SpA preparations obtained from naturally occurring Staphylococcus aureus bacteria as well as recombinant SpA from Staphylococcus xylosus were potent mitogens. Further purification of SpA from S. aureus showed that the mitogenic material was concentrated in the side fractions containing more basic molecules. Some staphylococcal enterotoxins are mitogenic for human cells and in order to test whether contaminating enterotoxins would be responsible for the mitogenic effect of SpA preparations, rabbit antibodies were produced against enterotoxin A and B. These antibodies inhibited activation of human cells induced by the enterotoxins used for immunization but did not affect the activation induced by SpA preparation. The addition of selected human sera to in vitro cultures resulted in an inhibition of the response induced by low doses of SpA. There was no clear relationship between these effects and the content of IgG antibodies against staphylococcal enterotoxins A, B, and Cl in the sera. Thus, we conclude that the mitogenicity of SpA preparations is caused by contaminating molecules, probably not enterotoxins A, B, or Cl.

Blood Physiological Phenomena↗
PubMed1989

Regulation of IgG1 and IgE synthesis by interleukin 4 in mouse B cells.

Mouse interleukin 4 (IL-4) has been shown to act on B cells as an induction factor for Ig class switch. We studied the characteristics of IL-4-regulated Ig isotype production in lipopolysaccharide (LPS)-stimulated splenic B-cell cultures with emphasis on the comparison between the IgG1 and IgE responses. The results show that the kinetics for the appearance of IgG1 and IgE isotypes are similar, but that the dose of IL-4 required for the induction of an IgE response is 3-10 times higher than that for an IgG1 response. No requirement for T cells was found for the induction of either isotype. Pre-incubation of cells for 24 h with IL-4 alone was sufficient to induce an IgG1 response when cells were recultured with LPS from days 1 to 6. However, the simultaneous presence of both IL-4 and LPS for at least 24 h was required for a detectable IgE response. For an optimal IgE response, IL-4 needed to be present for more than 72 h in LPS-activated cultures. The possible reasons for the different regulation of IgG1 and IgE responses are discussed.

Animals↗
PubMed1989

Serum IgE levels after bone marrow transplantation.

Total serum IgE levels were followed in 135 bone marrow transplant recipients in order to determine the clinical significance of post-transplant serum IgE monitoring. Patients with IgE levels less than 60 U/ml at the time of bone marrow transplantation (BMT) (59%) experienced at least one IgE peak. Patients with pretransplant IgE levels greater than or equal to 60 U/ml (16%) showed decreasing values following BMT. In 19% of patients, IgE levels were low and did not change up to 3 months after BMT. Increase in IgE levels coincided in time with engraftment (p less than 0.01) and acute graft-versus-host disease (GVHD) (p less than 0.01). Early IgE peaks were also seen in patients without GVHD. Maximal IgE values did not differ during grades II-IV GVHD compared with grades 0-1, but two or more peaks were more common in patients with grades II-IV (p less than 0.001). IgE peaks also appeared in patients receiving T cell-depleted marrow without GVHD. Syngeneic bone marrow recipients had high IgE levels after BMT. Two patients had increasing IgE values following reconditioning and retransplantation, but booster grafts had no effect on IgE levels. IgE levels were not changed during septicemia, herpes simplex virus or cytomegalovirus infections, and chronic GVHD. No linear correlation was found between serum IgE levels and CD4+/CD8+ ratios, percentages, or absolute numbers of either group of cells. It was concluded that serum IgE elevation is found in association with engraftment and acute GVHD, but is mainly caused by the conditioning treatment.

Acute Disease↗
PubMed1988

Enumeration of IFN-gamma-producing cells by flow cytometry. Comparison with fluorescence microscopy.

A new intracytoplasmic immunofluorescence staining to detect and quantify human interferon-gamma (IFN-gamma)-producing cells by means of flow cytometry is described. Mononuclear leukocytes, stimulated in vitro to produce IFN-gamma, were fixed and made permeable to antibodies by sequential exposure to paraformaldehyde and the detergent n-octyl-glucoside. Cytoplasmic IFN-gamma was demonstrated by indirect immunofluorescence using IFN-gamma-specific mouse monoclonal antibodies. The staining exhibited a very characteristic morphology and was localized in the Golgi apparatus. An excellent agreement between the enumeration of cytoplasmic IFN-gamma-positive cells by immunofluorescence microscopy and flow cytometry was noted. However, the latter has the advantage of a standardized control, is less labor consuming and is observer independent.

Adult↗
PubMed1988

How far does prophylaxis against infection in total joint replacement offset its cost?

Selection of a cost effective method of prophylaxis against infection for patients undergoing total joint replacement was shown to depend on the number of arthroplasties performed each year at individual hospitals. When 100 arthroplasties were performed each year the prophylactic use of systemic antibiotics minimised the total costs of the department--that is, the combined costs of prophylaxis and reoperation for deep sepsis. Some departments also used local antibiotic prophylaxis in the form of polymethylmethacrylate cement impregnated with gentamicin or a combination of systemic and local prophylaxis at almost as low a total cost and with comparable effect. Selection of a method of prophylaxis should not be determined solely on the basis of reducing costs. When a value was assigned to the effects of loss of health an economic optimum was established that allowed selection of a more costly method of prophylaxis together with further reductions in the incidence of infection and the need for reoperation.

Anti-Bacterial Agents↗
PubMed1988

Interleukin 4 instructs uncommitted B lymphocytes to switch to IgG1 and IgE.

Mouse interleukin 4 (IL 4) is a T cell-produced lymphokine with multiple effects on different cells types of the hematopoietic lineages. IL 4 has pronounced effects on B lymphocytes, where it induces high levels of IgG1 and IgE secretion in lipopolysaccharide-stimulated cultures that would otherwise secrete predominantly IgG3 and IgG2b (of the non-IgM isotypes). An important question is how IL 4 exerts its effect. Two main possibilities exist: (a) IL 4 instructs uncommitted B lymphocytes to IgG1 and IgE production; (b) IL 4 selects and expands an already precommitted B cell. In this study we show, by the use of limiting dilution analysis, that IL 4 dramatically increases the precursor frequency of IgG1 and IgE-secreting cells with no significant effect on the clone size, clearly suggesting that IL 4 instructs uncommitted B cells to switch to IgG1 and IgE. The fraction of total Ig precursors that can switch to the two isotypes is furthermore high. The high precursor frequency for IgE obtained in the presence of IL 4 further demonstrates that IL 4 is an important modulator of IgE responses.

Animals↗
PubMed1988

Relationship between serum neopterin and lymphocytic alveolitis in sarcoidosis.

We have previously found elevated levels of serum (S-) neopterin in patients with active sarcoidosis. In the present study we therefore investigated the relationship between elevated S-neopterin and sarcoid alveolitis as reflected in bronchoalveolar (BAL) findings. Patients with elevated percentages of BAL-lymphocytes (n = 19) had significantly higher (p less than 0.01) S-neopterin levels (median 12.1 nmol/L) than those (n = 11) with normal percentages (median 8.5 nmol/L). Of 19 patients with elevated lymphocyte percentage 18 had increased S-neopterin. There was a significant correlation between S-neopterin levels and the concentration (p less than 0.01) as well as the percentage (p less than 0.05) of BAL-lymphocytes. On the other hand, no correlation was found between S-neopterin and the BAL-albumin/S-albumin ratios, the concentration of macrophages or the concentration of angiotensin converting enzyme in the BAL fluid. The results indicate a close relationship between S-neopterin and lymphocytic alveolitis in sarcoidosis. Furthermore, a possible relationship between elevated S-neopterin and the ratios of T helper to T cytotoxic-suppressor cells (TH/TC-S) in blood, assumed to reflect changes of the ratios in alveolitis, was examined. However, 34 of 37 sarcoid patients had TH/TC-S ratios within the normal range. The ratios of patients with normal and elevated S-neopterin did not differ.

Adult↗
PubMed1987

Inhibition of human vitamin-K-dependent protein-S-cofactor activity by a monoclonal antibody specific for a Ca2+-dependent epitope.

Protein S is an anticoagulant vitamin-K-dependent plasma protein functioning as a cofactor to activated protein C in the degradation of factors Va and VIIIa. A murine monoclonal antibody, HPS 7, specific for a calcium-stabilized epitope in human protein S, is described. The epitope was available in intact protein S, both in its free form and when protein S was bound to C4b-binding protein. It disappeared upon reduction of disulfide bridges and also after thrombin of chymotrypsin cleavage of protein S. Thrombin cleaves protein S close to the calcium-binding region containing gamma-carboxyglutamic acid (Gla). The cleaved protein still contains the Gla region, linked by a disulfide bridge, but it has a lower affinity for calcium and no protein C cofactor activity. The thrombin-mediated cleavage of protein S could be inhibited by HPS 7. The Ka for the interaction between protein S and the monoclonal was estimated to be approximately 0.7 X 10(8) M-1. Half-maximal binding between HPS 7 and protein S was observed at a calcium concentration of 0.50 mM, indicating that saturation of the Gla region with calcium was required for the interaction. The recently reported Gla-independent high-affinity calcium binding did not induce the epitope. The calcium-dependent binding of protein S to phospholipid vesicles as well as the protein C cofactor activity was inhibited by HPS 7. The data suggests that the epitope for HPS 7 is located in the Gla region of protein S or in the closely positioned thrombin-sensitive region.

Animals↗