Low HLA-DR Expression Research Articles

Triggering receptor expressed on myeloid cells-1 expression on monocytes is associated with inflammation but not with infection in acute pancreatitis

IntroductionAcute pancreatitis (AP) is usually a mild and self-limiting disease, but some patients develop a severe form that is associated with high mortality. In AP, local inflammation is followed first by the systemic inflammatory response syndrome and then by the compensatory anti-inflammatory response syndrome, which is defined by low human leukocyte antigen (HLA)-DR expression on monocytes, increased concentration of the anti-inflammatory cytokine IL-10, and decreased monocyte function. Our aim was to measure the expression of triggering receptor expressed on myeloid cells (TREM)-1 (a proposed marker of infection or inflammation) and HLA-DR on monocytes, and the serum concentrations of IL-6 (a proinflammatory cytokine) and IL-10 in patients with AP to determine whether these markers can identify patients at high risk of developing severe AP or infection.MethodsFifty healthy volunteers, 18 patients with mild AP, and 11 patients with severe AP were included in this study. Samples were taken at admission and one and three days later. TREM-1 and HLA-DR expression was evaluated by flow cytometry, and soluble TREM-1, IL-6 and IL-10 concentrations were measured by ELISA.ResultsTREM-1 expression was higher in patients with AP than in healthy volunteers, but there was no difference between patients with mild and severe AP. TREM-1 expression was not associated with mortality or with the presence of infection. Soluble TREM-1 concentration in serum was higher in non-survivors than in survivors. HLA-DR expression was lower and IL-6 concentration higher in patients with severe AP and in infected patients.ConclusionsIncreased TREM-1 expression was associated with the presence of inflammation but not infection in AP. In patients with AP, low HLA-DR expression and high IL-6 concentration could predict severity and infection in samples taken shortly after admission.

Prognostic Utility of Immunophenotyping in Diffuse Large B-Cell and Follicular Lymphomas

Patients with Diffuse Large B-Cell Lymphoma (DLBCL) and Follicular Lymphomas (FL) exhibit marked variability in survival, the international prognostic index (IPI) predicts the cure with chemotherapy as IPI is a well established predictor of outcome in DLBCL and FL. Biological prognostic markers including expression on of BCL2, BCL6, CD5, CD10, and HLA-DR have been described as IPI independent prognostic factors. The purpose of this study is to high light how these biomarkers might be incorporated into current risk – adjustment models for prognosis. Biological parameters were evaluated by flowcytometric immunophenotyping of 96 patients with DLBCL and FL.In our study, Superior overall survival (OS) was associated with high expression of HLA-DR in DLBCL either do novo or on top of FL (p < 0.001 for both group), and with low expression of CD 5 and BCL2 in de novo DLBCL (p < 0.001 for both ) independently of the IPI. On the other hand Inferior overall survival was established with high expression of BCL6 in DLBCL. However Inferior progression free survival (PFS) was independently correlated with high expression of BCL2 (p = 0.007 and 0.018 ) and lower expression of HLA-DR ( p=0.003 and 0.03 ) in both de novo DLBCL and on top of follicular, but not in FL and with high expression of CD10 in de novo DLBCL only ( p<0.001 ).In 96 patients with DLBCL and FL treated with risk adapted therapy, low HLA-DR expression is associated with poor outcome in DLBCL either de novo or on top of follicular but not in a FL group. the time is right to begin to consider how these biomarkers should be incorporated into current prognostic models to move beyond the clinically based IPI.

Fonsecaea pedrosoiinfection induces differential modulation of costimulatory molecules and cytokines in monocytes from patients with severe and mild forms of chromoblastomycosis

The host defense mechanism in chromoblastomycosis has not been thoroughly investigated. It has been suggested that cell-mediated immunity in patients with long-standing chromoblastomycosis is somehow impaired. As a result, these individuals became unable to develop an efficient immune reaction. Many studies have shown that monocyte-derived macrophages exhibit critical activities in immunity to microorganisms. Moreover, the ability of cells from the monocytic lineage to process and present antigens, to produce cytokines, and to provide costimulatory signals confirms their pivotal role in the initiation of specific immune responses. In the present study, it was observed that monocytes from patients with a severe form of disease had a higher production of IL-10 and a lower expression of HLA-DR and costimulatory molecules when stimulated with specific antigen or LPS. Immune modulation with recombinant IL-12 or anti-IL-10 can restore the antigen-specific Th1-type immune response in chromoblastomycosis patients by up-regulating HLA-DR and costimulatory molecules in monocytes. Therefore, our data show that monocytes from patients with different clinical forms of chromoblastomycosis present distinct phenotypic and functional profiles. This observation suggests possible mechanisms that control the T cell response and influence their role in the development of pathology.

Cup-like acute myeloid leukemia: new disease or artificial phenomenon?

We investigated cup-like nuclear morphology of acute myeloid leukemia blasts in 266 randomly selected patients and its association with hematologic findings, disease markers and outcome data. Cup-like acute myeloid leukemia was diagnosed in 55 patients (21%). It was associated with female sex, high white blood cell and blast cell counts, normal karyotype, and low CD34 and HLA-DR expression. Mutations of FLT3, NPM1 or both were detected in 84.9% compared with 58.1% in cases without this morphology (p=0.001). There was no influence on response to treatment or survival. Therefore, cup-like nuclear morphology is an indicator of normal karyotype and should guide more specific molecular analyses.

Identification of a New Subset of Myeloid Suppressor Cells in Peripheral Blood of Melanoma Patients With Modulation by a Granulocyte-Macrophage Colony-Stimulation Factor–Based Antitumor Vaccine

Phenotypic and functional features of myeloid suppressor cells (MSC), which are known to serve as critical regulators of antitumor T-cell responses in tumor-bearing mice, are still poorly defined in human cancers. Here, we analyzed myeloid subsets with suppressive activity present in peripheral blood of metastatic melanoma patients and evaluated their modulation by a granulocyte-macrophage colony-stimulating factor (GM-CSF)--based antitumor vaccine. Stage IV metastatic melanoma patients (n = 16) vaccinated with autologous tumor-derived heat shock protein peptide complex gp96 (HSPPC-96) and low-dose GM-CSF provided pre- and post-treatment whole blood specimens. Peripheral-blood mononuclear cells (PBMCs) were analyzed by flow cytometry, separated into cellular subsets, and used for in vitro proliferation assays. PBMCs from stage-matched metastatic melanoma patients (n = 12) treated with non-GM-CSF-based vaccines (ie, HSPPC-96 alone or interferon alfa/melanoma-derived peptides) or sex- and age-matched healthy donors (n = 16) were also analyzed for comparison. The lack of or low HLA-DR expression was found to identify a CD14+ cell subset highly suppressive of lymphocyte functions. CD14+HLA-DR-/lo cells were significantly expanded in all metastatic melanoma patients, whereas they were undetectable in healthy donors. Suppressive activity was mediated by transforming growth factor beta (TGF-beta), whereas no involvement of the arginase and inducible nitric oxide synthase pathways could be detected. CD14+HLA-DR-/lo cells, as well as spontaneous ex vivo release and plasma levels of TGF-beta, were augmented after administration of the HSPPC-96/GM-CSF vaccine. No enhancement of the CD14+-mediated suppressive activity was found in patients receiving non-GM-CSF-based vaccines. CD14+HLA-DR-/lo cells exerting TGF-beta-mediated immune suppression represent a new subset of MSC potentially expandable by the administration of GM-CSF-based vaccines in metastatic melanoma patients.

Immunophenotype as prognostic factor for diffuse large B-cell lymphoma in patients undergoing clinical risk-adapted therapy

For patients with diffuse large B-cell lymphoma (DLBCL), the International Prognostic Index (IPI) predicts the likelihood for cure with chemotherapy. Biological parameters, including expression of Bcl-6, Bcl-2, CD10, major histocompatibility complex class II, and categorization as germinal center (GC) type have been described as IPI-independent prognostic factors. Biological parameters were evaluated retrospectively by immunohistochemistry in 60 consecutive DLBCL patients of the prerituximab era. Forty-one of 60 patients underwent a risk-adapted treatment strategy including autologous stem-cell transplantation for high-risk patients (age-adjusted IPI = 2-3; slow response to chemotherapy). Bcl-6 expression was associated with superior overall survival (OS) independently of the IPI. Inferior progression-free survival (PFS) was independently correlated with high expression of Bcl-2 and low positivity for HLA-DR and CD10. Distinction into GC and non-GC DLBCL on the basis of Bcl-6, CD10, and IRF-4 expression had no independent prognostic value. Within the risk-adapted treatment strategy, only HLA-DR retained a prognostic impact on OS (P = 0.0058) and PFS (P = 0.0002). In 60 patients with DLBCL treated with risk-adapted therapy, immunohistochemical subcategorization of DLBCL into GC and non-GC type has little clinical value. The IPI-associated risk appears to be mitigated by intensified upfront therapy. Low HLA-DR expression is associated with poor outcome after intensified upfront therapy. Therefore, additional treatment modalities appear to be required.

Characterization of the Optimal Culture Conditions for Clinical Scale Production of Human Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are multipotent cells defined by multilineage potential, ease to gene modification, and immunosuppressive ability, thus holding promise for tissue engineering, gene therapy, and immunotherapy. They exhibit a unique in vitro expansion capacity, which, however, does not compensate for the very low percentage in their niches given the vast numbers of cells required for the relative studies. Taking into consideration the lack of a uniform approach for MSC isolation and expansion, we attempted in this study, by comparing various culture conditions, to identify the optimal protocol for the large-scale production of MSCs while maintaining their multilineage and immunosuppressive capacities. Our data indicate that, apart from the quality of fetal calf serum, other culture parameters, including basal medium, glucose concentration, stable glutamine, bone marrow mononuclear cell plating density, MSC passaging density, and plastic surface quality, affect the final outcome. Furthermore, the use of basic fibroblast growth factor (bFGF), the most common growth supplement in MSC culture media, greatly increases the proliferation rate but also upregulates HLA-class I and induces low HLA-DR expression. However, not only does this upregulation not elicit significant in vitro allogeneic T cell responses, but also bFGF-cultured MSCs exhibit enhanced in vivo immunosuppressive potential. Besides, addition of bFGF affects MSC multilineage differentiation capacity, favoring differentiation toward the osteogenic lineage and limiting neurogenic potential. In conclusion, in this report we define the optimal culture conditions for the successful isolation and expansion of human MSCs in high numbers for subsequent cellular therapeutic approaches.

Human leukocyte antigen expression by peritoneal macrophages from women with pelvic endometriosis is depressed but coordinated with costimulatory molecule expression

To investigate the macrophage response in endometriosis, we determined expression of human leukocyte antigen (HLA)-ABC, HLA-DR, and their costimulatory molecules by peritoneal fluid (PF) macrophages. Case-control study of immunologic markers. University hospital. We compared 38 Japanese women with endometriosis with 59 control subjects who were given other laparoscopic diagnoses. Venipuncture and laparoscopic peritoneal fluid collection. Expression of HLA-ABC, HLA-DR, CD54, CD40, CD58, CD80, and CD86 by peripheral blood (PB) monocytes and PF macrophages was quantitated as mean fluorescence intensities by flow cytometry. Expression of each marker on PF macrophages was divided by that on PB monocytes as an index of macrophage activation (macrophage activation ratio). In women with endometriosis, PF macrophages showed significant positive correlations between expression of HLA-ABC and other costimulatory molecules and also between HLA-DR and their costimulatory molecules. However, expression of HLA-ABC and DR by PF macrophages, and also their activation ratios, were significantly lower than in controls. Coordination with costimulatory molecules but relatively low expression of HLA-ABC and HLA-DR indicates a positive but limited immune response (antigen presentation) to events in the peritoneal cavity in women with endometriosis. This may induce immune tolerance to implanted or metaplastic endometrial tissue.

Coagulopathy in HLA-DR Antigen-Negative Acute Myeloid Leukemia.

Background: HLA-DR antigen is present on hematopoietic progenitors and granulocyte/monocyte, erythrocyte and megakaryocytic precursors but absent at the promyelocytic stage during myeloid cell maturation. In accordance with this, majority of promyelocytic leukemia (APL) cells were negative for HLA-DR. Meanwhile, some of non-APL acute myeloid leukemia (AML) cells is found to express HLA-DR. However, the clinical significance of HLA-DR antigen on AML cells is currently unclear.Purpose: We sought to determine the prevalence and clinical characteristics of negativity in HLA-DR expression by retrospectively analyzing 181 consecutive patients with de novo adult AML.Patients and Methods: AML patients examined in the current study (aged 15–86 years) had been diagnosed between August 1995 and July 2004, and categorized to M0 (8 patients), M1 (35), M2 (74), M3 (20), M4 (25), M5 (15), and M6 (4), based on the FAB classification. Median follow-up time was 19.3 months. Phenotypic analyses of leukemic cells were performed using CD45 gating methods. HLA-DR-negative AML was defined as HLA-DR expression less than 20% of cells in the CD45 leukemic cell gate.Results: Among 181 patients, HLA-DR antigens were not detected on AML cells from 46 patients; 20 with APL and 26 with non-APL (non-APL/DR(−)), the latter of which included M0 (2 patients), M1 (15), M2 (7), M4 (2). Leukemic cells from other non-APL patients were HLA-DR-positive (non-APL/DR(+)). None of non-APL/DR(−) patients had t(15;17) nor PML/RARa rearrangement on cytogenetic analysis. Twenty out of 26 patients with non-APL/DR(−) had normal chromosome, and 6 had abnormal karyotypes. In the non-APL/DR(−) group, various degrees of nuclear folding, convolution, or lobulation were observed in 9 patients. Although treatment response and overall survival rate were similar in the three groups (APL, non-APL/DR(−), and non-APL/DR(+)), both FDP levels at diagnosis (57.3 vs 13.2, p<0.05) and maximal FDP levels (232.6 vs 43.8, p<0.01) were significantly higher in non-APL/DR(−) compared with non-APL/DR(+). The maximal FDP levels in the non-APL/DR(−) patients were comparable to those in the APL patients. FDP levels greater than 40 mg/ml were significantly more prevalent in the non-APL/DR(−) than in the the non-APL/DR(−) group. Logistic regression analysis demonstrated that low HLA-DR expression was an independent risk factor for FDP > 40 mg/ml.Conclusion: Our study suggests that AML with negative HLA-DR antigen tend to be associated with abnormality in coagulation and fibrinolysis even if they are genetically non-APL. We propose that more attention should be paied for HLA-DR expression to avoid a devastating coagulopathy which carries a high risk of mortality unless specifically addressed.

The anti-inflammatory response dominates after septic shock: association of low monocyte HLA-DR expression and high interleukin-10 concentration

The diminished expression of HLA-DR on monocytes has been proposed as a reliable marker of immunosuppression occuring during septic shock. The objective of the present observational study was to establish the time-dependent relation between plasma cytokines interleukin (IL)-10, transforming growth factor (TGF)-β1, tumor necrosis factor (TNF)-α and monocyte HLA-DR expression in 38 adult patients with septic shock. All patients (mortality at 28 days: 42%, mean admission SAPS II score: 54) had decreased HLA-DR expression. This expression was significantly lower in non-survivors at all time points. All patients had elevated IL-10 concentrations, the highest values were found in non-survivors. IL-10 was the sole cytokine to significantly correlate with HLA-DR expression ( r: −0.6, p < 0.001). TNF and TGF values did not provide any prognostic information. TGF levels from septic patients were even found to be decreased in comparison with normal values which suggested that IL-10 is likely more important than TGF regarding the immunosuppressive properties of septic patients’ plasma. This preliminary work showed that, at the systemic level, the anti-inflammatory response dominated after septic shock. Monocyte HLA-DR expression and IL-10 measurement deserve to be determined in parallel in a larger longitudinal study. They might constitute helpful indicators for staging patients and making a decision about whether to institute a therapy with molecules able of reversing sepsis-induced immunosuppression.

Monocytes from patients with indeterminate and cardiac forms of Chagas' disease display distinct phenotypic and functional characteristics associated with morbidity.

Many studies have demonstrated that monocyte-derived macrophages display critical activities in immunity to parasites. The ability of these cells to process and present antigens, produce cytokines, and provide costimulatory signals demonstrates their pivotal role in initiating immune responses. Although potential modulatory function has been attributed to monocytes from patients with Chagas' disease, a systematic phenotypic and functional analysis of these cells has not been performed. In this work, we analyzed the ex vivo expression of important surface molecules (CD11b and HLA-DR) and immunoregulatory cytokines (interleukin-10 [IL-10], IL-12 and tumor necrosis factor alpha [TNF-alpha]) in CD14(+) and CD14(-) monocytes from Chagas' disease patients with polar clinical forms of the disease: indeterminate or severe cardiac. We also evaluated the influence of in vitro infection with T. cruzi in the expression of such molecules. We observed that monocytes from indeterminate-disease patients display lower levels of HLA-DR than those from noninfected individuals both ex vivo and after in vitro infection with T. cruzi. Although ex vivo expression of CD11b was similar among the groups, in vitro infection led to decreased expression of this molecule by monocytes from Chagas' disease patients but not from noninfected individuals. Analysis of the expression of immunoregulatory cytokines showed that while monocytes from indeterminate-disease patients are committed to IL-10 expression, a higher percentage of monocytes from cardiac-disease patients express TNF-alpha after exposure to live parasites. These results suggest that monocytes from indeterminate-disease patients display modulatory characteristics related to low HLA-DR and high IL-10 expression whereas monocytes from cardiac-disease, patients may be committed to induction of inflammatory responses related to high TNF-alpha expression.

Predictive value of interleukins 6, 8 and 10, and low HLA-DR expression in acute renal failure.

HLA-DR expression and plasma levels of pro- and anti-inflammatory cytokines (IL-6, IL-8 and IL-10) and their predictive value concerning survival of critically ill systemic inflammatory response syndrome (SIRS) patients with and without acute renal failure (ARF) were evaluated. A total of 103 consecutive adult patients with SIRS from 2 university hospital intensive care units participated in the study. Laboratory data for all patients were prospectively collected on the day of admission and 2 days thereafter. Patients with acute renal failure (ARF) and non-ARF patients were compared by Mann-Whitney U-test. Independent predictors of mortality were tested using forward stepwise logistic multiple regression analysis. The discriminative power of different variables was tested using receiver operating characteristic (ROC) curve analysis. ARF developed in 36 patients (35%). ARF patients showed significantly lower HLA-DR expression and higher plasma levels of IL-6, IL-8 and IL-10 than non-ARF patients. In ARF, moderate discriminative power in predicting survival was observed for day 2 IL-6 and IL-10 plasma levels (AUCs 0.703 and 0.749, respectively). We found no clinically significant discriminative power in predicting survival of ARF patients for monocyte HLA-DR expression or cytokine plasma levels. Therefore, our results do not support the use of HLA-DR expression or cytokine plasma levels for that purpose.

HLA-DR regulation and the influence of GM-CSF on transcription, surface expression and shedding

Low surface HLA-DR expression is a feature in sepsis. However, the mechanisms that regulate HLA-DR expression have not been elucidated. The current study investigates regulation of HLA-DR gene transcription, post transcriptional events and shedding of surface HLA-DR, as well as the regulation of HLA-DR by GM-CSF and an immunomodulatory cytokine. Plasma and PBMC were collected from septic patients and healthy volunteers. An ELISA was developed to measure soluble HLA. PCR techniques were used to determine HLA-DR mRNA levels, and flow cytometry and fluorescent microscopy were used for measurement of surface expressed and intracellular HLA-DR. Septic patients fulfilling the criteria of the American College of Chest Physicians (ACCP) for sepsis were recruited for the study (n=70). HLA-DR was measured on three consecutive days, days seven and fourteen. Patients were excluded from the study if on immunosuppressive therapy. Results: Higher levels of shed HLA-DR were found in the plasma of septic patients compared to healthy controls. The level of HLA-DR mRNA was significantly lower in septic patients compared to healthy controls, however an increased intracellular HLA-DR expression was observed. When HL-60 cells were treated with GM-CSF, gene transcription, surface expression and shedding of HLA-DR were all up-regulated. These results indicate that the mechanisms involved in the regulation of HLA-DR in sepsis include shedding of HLA-DR from the cell surface and regulation of HLA-DR gene transcription. Post-translational processing of HLA-DR was also seen to be compromised. GM-CSF was shown to regulate HLA-DR at all these levels.

Proinflammatory blood monocytes: main effector and target cells in systemic and renal disease; background and therapeutic implications

Although peripheral blood monocytes are heterogeneous, they all express the CD14 molecule, a multifunctional receptor, and part of the toll-like membrane receptor complex. In healthy persons, a minor subset (8%) coexpresses CD14 and CD16, a low affinity Fc-gamma type III receptor. This subpopulation shows characteristics of tissue macrophages and expands greatly in acute and chronic infections, systemic inflammatory syndromes, hyperlipidedemia, AIDS and renal failure. CD14+/CD16+ monocytes (Mo) exhibit higher phagocytosis activity than CD14++/CD16-negative monocytes and synthesize high levels of interleukin-1, TNF-alpha and HLA-DR, -DP and -DQ antigens. Glucocorticoids (and interleukin-4), and successful therapy in patients with inflammatory and septic complications lead to a down-regulation in the expression of CD14 and deplete CD14+/CD16+-proinflammatory Mo. Recovery of low monocytic HLA-DR expression parallels clinical improvement. Serial analyses of Mo phenotypes may be useful tools for monitoring patients receiving immunosuppressive and anti-inflammatory therapy respectively.

Coordinated but depressed expression of human leukocyte antigen-DR, intercellular adhesion molecule-1, and CD14 on peritoneal macrophages in women with pelvic endometriosis

Objective To investigate the macrophage response in endometriosis, we determined the expression of human leukocyte antigen (HLA)-DR, intercellular adhesion molecule (ICAM)-1, and CD14 on peritoneal macrophages. Design Case-control study of immunologic markers. Setting University hospital. Patient(s) Forty-five Japanese women with endometriosis were compared with 48 control subjects with other laparoscopic diagnoses. Intervention(s) Venipuncture and laparoscopic peritoneal fluid (PF) collection. Main outcome measure(s) Expression of HLA-DR, ICAM-1, and CD14 on peripheral blood (PB) monocytes and PF macrophages were quantitated as mean fluorescence intensities by flow cytometry. Expression of each marker on PF macrophages was divided by that on PB monocytes, as an index of macrophage activation (macrophage activation ratio). Result(s) In women with endometriosis, PF macrophages showed significant positive correlations between expression of HLA-DR and ICAM-1, HLA-DR and CD14, and ICAM-1 and CD14. However, expression of individual markers on PF macrophages and their activation ratios were significantly lower than in control. Conclusion(s) Coordinated but relatively low expression of HLA-DR, ICAM-1, and CD14 on PF macrophages indicates a positive but limited immune response to events in the peritoneal cavity in women with endometriosis, which may induce immune tolerance to implanted or metaplastic endometrial tissue.

The immunomodulatory role of human conjunctival epithelial cells.

To characterize phenotypically the primary epithelial cells obtained from normal bulbar conjunctival biopsy specimens and a human conjunctival epithelial cell line (Wong-Kilbourne derivative of Chang conjunctiva; ChWK) with regard to their immunostimulatory function. The effects on expression of HLA-DR and costimulatory molecules (CD80, CD86, ICAM-1, and CD40) on normal conjunctival epithelial cells and ChWK treated with various cytokines (IFN-gamma, TNF-alpha, IL-4, and IL-13) were determined using flow cytometry and confocal microscopy. Epithelial cells were successfully grown from conjunctival explants and cultures passaged three times, while retaining their cell surface markers. At least 97% of primary epithelial cells (n = 10) and more than 96% of ChWK cells (n = 10) were cytokeratin positive by flow cytometry and immunocytochemistry and demonstrated epithelial cell morphology. Both primary conjunctival epithelial cells and ChWK had a low basal expression of HLA-DR and ICAM-1, and both were upregulated by IFN-gamma. For ChWK cells, CD80 and CD86 were constitutively expressed at low levels. CD80 was significantly upregulated after IFN-gamma treatment (P = 0.043), whereas IL-4 induced a significant upregulation of CD86 (P = 0.039). Treatment with IL-13 and TNF-alpha did not induce significant effects. The ability of conjunctival epithelial cells to express costimulatory molecules suggests a proinflammatory role for conjunctival epithelial cells.

Age-related low expression of HLA-DR molecules on monocytes of term and preterm newborns with and without signs of infection.

Presentation of human leucocyte antigen (HLA) molecules is an important part of an efficient immune response. Since bacterial infections are more common in newborns, we hypothesized that the level of HLA-DR expression may influence the host defense system. HLA-DR expression on monocytes was examined by flow cytometry during the first week of life of term and preterm neonates with and without signs of infection and of adults. HLA-DR expression of term and preterm newborns with or without signs of infection was lower compared with adults during the first day of life (p<0.0001). Prematurity correlates with lower expression in neonates with gestational age less than 32 weeks (p=0.0008). HLA-DR expression in neonates with signs of infection was decreased compared to healthy neonates (p=0.0196). Maternal conditions such as preeclampsia, prenatal treatment with steroids and mode of delivery had no influence on the expression of HLA-DR. In contrast, newborns with respiratory distress syndrome but without signs of infection showed reduced HLA-DR expression (p=0.0370). Low HLA-DR expression on monocytes contributes to impaired neonatal host defense, especially in preterm neonates.

Lipopolysaccharide—cell interaction and induced cellular activation in whole blood of septic patients

We used biotinylatedLPS (LPSb) and flow cytometry to study LPS—monocyte interaction and LPS-induced cellular activation in whole blood from septic patients (SP). Expression of surface activation markers was evaluated on monocytes (HLA-DR) and T lymphocytes (CD69 and CD95), and intracellular TNF-α on monocytes. Saturating curve and kinetics of LPSb detection on monocytes were similar in SP and healthy volunteers (HV). LPSb bound to monocytes was detected after 5 min of incubation in both groups, with a more pronounced decay in SP. Monocytes from SP had a lower expression of HLA-DR as compared to HV, both constitutive and upon LPS stimulation. The proportion of monocytes producing TNF-α after LPS stimulus was higher in HV than SP (mean ± SD = 25.2 ± 14.2% and 2.2 ± 2.6%, respectively, P &lt; 0.001). LPS-induced CD69 on T CD8+ and CD8— lymphocytes was similar for patients and controls. Expression of CD95 on T lymphocytes was higher in SP as compared to HV on T CD8+ cells (GMFI, mean ± SD = 22.3 ± 14.6 and 8.6 ± 5.0, respectively, P = 0.01) and CD8— cells (GMFI, mean ± SD = 28.3 ± 7.7 and 14 ± 4.3 respectively, P &lt; 0.001). Thus, monocytes and lymphocytes seem to respond differently to LPS in septic patients. Monocyte hyporesponsiveness appears not to be related to a decreased binding capacity of LPS, but rather to an impaired signal transduction.

Alterations in the number of circulating leucocytes, phenotype of monocyte and cytokine production in patients undergoing cardiothoracic surgery.

Changes in the differential blood cell count, monocyte phenotype and the cytokine plasma levels in a group of seven patients with cardiac surgery/cardiopulmonary bypass (CPB) and nine patients with thoracic surgery/without CPB, both receiving identical opioid-based anaesthetic technique, were assessed. A significant reduction in the number of circulating lymphocytes and monocytes was observed after anaesthesia and surgery. Interestingly, at the end of surgery as well as 1 day post-surgery a marked increase in the number of granulocytes was noted. General anaesthesia and surgery caused a significant reduction of HLA-DR and CD11c/CD18 molecules, starting immediately after induction of anaesthesia, and an increase of CD64 at day 1 after anaesthesia. The use of a CPB was followed by a significant reduction of CD32, CD16, CD54 and HLA-ABC antigens expression at the end of surgery. One day after surgery these parameters returned nearly to baseline values with the exception of CD54. A monocyte subpopulation, characterized by low CD14, high CD16 and HLA-DR expression (CD14+CD16+HLA-DR++) was found in both groups at each time point, and the percentage of this cell subset decreased from baseline to 24 h. The plasma concentrations of IL-6 and IL-10 increased considerably during CPB. No dynamic changes of IL-1 level due to surgery or CPB were found. We conclude that anaesthesia as well as the use of CPB induced profound alterations in the number of circulating leucocytes, and in the phenotype of monocyte and cytokine production.

Peripheral blood dendritic cells in children with acute Plasmodium falciparum malaria

AbstractThe importance of dendritic cells (DCs) for the initiation and regulation of immune responses not only to foreign organisms but also to the self has raised considerable interest in the qualitative and quantitative analysis of these cells in various human diseases.Plasmodium falciparum malaria is characterized by the poor induction of long-lasting protective immune responses. This study, therefore, investigated the percentage of peripheral blood DCs as lineage marker–negative and HLA-DR+ or CD83+cells in healthy children and in children suffering from acute malaria in Kilifi, Kenya. Comparable percentages of CD83+ DCs were found in peripheral blood of healthy children and children with malaria. However, the percentage of HLA-DR+ peripheral blood DCs was significantly reduced in children with malaria. The results suggest that a proportion of peripheral blood DCs may be functionally impaired due to the low expression of HLA-DR on their surface.