Human Leukocyte antigen-DR Levels Research Articles

Evaluation of Changes in Leukocyte Surface Markers in the Early Diagnosis of Late-Onset Neonatal Sepsis

Abstract Objective This study aimed to evaluate the cluster of differentiation (CD)64, CD16, CD11b, CD63 human leukocyte antigen-DR (HLA-DR), and CD62L leukocyte surface marker abnormalities using flow cytometry in the early diagnosis of late-onset neonatal sepsis. Methods Forty-four neonates were included in this study. Of them, 22 neonates with clinical late-onset neonatal sepsis were included in the study group, and the remaining 22 neonates without sepsis were considered the control group. Complete sepsis screening was performed. Additionally, monocyte and neutrophil surfaces marker were examined using flow cytometry. Results The expression of the leukocyte surface markers CD16 and CD64 on monocytes and neutrophils was significantly higher in the study group than in the control group (p < 0.05), while the CD63, CD62L, CD11b, and HLA-DR levels were similar to those in the control group (p > 0.05). Furthermore, receiver operating characteristic curve analysis indicated that neutrophil CD64 (nCD64) is a diagnostic marker for neonatal sepsis, with an area under the curve of 0.901. The CD64 and CD16, which are the respective leukocyte surface markers on neutrophils and monocytes, are useful tests in the early diagnosis of late-onset neonatal sepsis. Conclusion In addition to acute phase proteins, cell surface antigens such as CD16 and more specifically CD64 should be used in routine investigations for the early diagnosis of late-onset neonatal sepsis. Such use in combination with acute phase reactants can improve diagnostic accuracy.

Impact of Body Mass Index on the Survival of Patients with Sepsis with Different Modified NUTRIC Scores.

Nutritional status affects the survival of patients with sepsis. This retrospective study analyzed the impact of body mass index (BMI) and modified nutrition risk in critically ill (mNUTRIC) scores on survival of these patients. Data of 1291 patients with sepsis admitted to the intensive care unit (ICU) were extracted. The outcomes were mortality, duration of stay, ICU stay, and survival curve for 90-day mortality. Logistic regression analysis was performed to examine the risk factors for mortality. Cytokine and biomarker levels were analyzed in 165 patients. The 90-day survival of underweight patients with low mNUTRIC scores was significantly better than that of normal-weight patients with low mNUTRIC scores (70.8% vs. 58.3%, respectively; p = 0.048). Regression model analysis revealed that underweight patients with low mNUTRIC scores had a lower risk of mortality (odds ratio = 0.557; p = 0.082). Moreover, normal-weight patients with low mNUTRIC scores had the lowest human leukocyte antigen DR (HLA-DR) level on days 1 (underweight vs. normal weight vs. overweight: 94.3 vs. 82.1 vs. 94.3, respectively; p = 0.007) and 3 (91.8 vs. 91.0 vs. 93.2, respectively; p = 0.047). Thus, being underweight may not always be harmful if patients have optimal clinical nutritional status. Additionally, HLA-DR levels were the lowest in patients with low survival.

Expression of peripheral blood monocyte human leukocyte antigen DR in patients with cardiac arrest and its clinical significance

Background: In the early period of spontaneous circulation (ROSC), the body may show severe immunosuppression and excessive activation of inflammatory response, This is very similar to sepsis in many ways. Objective: The aim of this study is to observe changes of the early expression of monocyte human leukocyte antigen DR in patients with cardiac arrest, so as to explore the clinical significance of the related immune assessment and prognosis prediction. Methods: A total of 43 patients with cardiac arrest who have been treated in the emergency department of Beijing Chaoyang Hospital from January 2015 to February 2018 are selected. By taking the survival rate on the 28th day of hospitalization as the end of observation, the patients are divided into the survival group and the death group. Changes of APACHE-II scores and monocyte human leukocyte antigen DR levels on the first, second, and third day after admission are analyzed. Results: On the first, second, and third day after onset, cardiac arrest patients show significantly decreased levels of monocyte human leukocyte antigen DR which are obviously lower in the death group than in the survival group. In addition, human leukocyte antigen DR levels were significantly negatively correlated with APACHE-II scores. Conclusion: The expression of monocyte human leukocyte antigen DR is proven to be an ideal indicator to evaluate the immune function and prognosis of cardiac arrest patients. A constantly low expression of human leukocyte antigen DR indicates impaired immune function and increased mortality of patients.

Adoptive transfer of xenoantigen‑stimulated T cell receptor Vβ‑restricted human regulatory T cells prevents porcine islet xenograft rejection in humanized mice.

Polyclonal expansion of human regulatory T cells (Tregs) prevents xenogeneic rejection by suppressing effector T cell responses in vitro and in vivo. However, a major limitation to using polyclonally expanded Tregs is that they may cause pan-immunosuppressive effects. The present study was conducted to compare the ability of ex vivo expanded human xenoantigen-stimulated Tregs (Xeno-Treg) and polyclonal Tregs (Poly-Treg) to protect islet xenografts from rejection in NOD-SCID interleukin (IL)-2 receptor (IL2r)γ−/− mice. Human cluster of differentiation (CD)4+CD25+CD127lo Tregs, expanded either by stimulating with porcine peripheral blood mononuclear cells (PBMCs) or anti-CD3/CD28 beads, were characterized by immune cell phenotyping, T cell receptor (TCR) Vβ CDR3 spectratyping and performing suppressive activity assays in vitro. The efficiency of adoptively transferred ex vivo human Tregs was evaluated in vivo using neonatal porcine islet cell clusters (NICC) transplanted into NOD-SCID IL-2rγ−/− mice, which received human PBMCs with or without Xeno-Treg or Poly-Treg. Xeno-Treg, which expressed increased levels of human leukocyte antigen-DR and secreted higher levels of IL-10, demonstrated enhanced suppressive capacity in a pig-human mixed lymphocyte reaction. Spectratypes of TCR Vβ4, Vβ10, Vβ18 and Vβ20 in Xeno-Treg showed restriction and expanded clones at sizes of 205, 441, 332 and 196 respectively, compared to those of Poly-Treg. Reconstitution of mice with human PBMCs and Poly-Treg resulted in NICC xenograft rejection at 63 days. Adoptive transfer with human PBMCs and Xeno-Treg prolonged islet xenograft survival beyond 84 days, with grafts containing intact insulin-secreting cells surrounded by a small number of human CD45+ cells. This study demonstrated that adoptive transfer of ex vivo expanded human Xeno-Treg may potently prevent islet xenograft rejection in humanized NOD-SCID IL2rγ−/− mice compared with Poly-Treg. These findings suggested that adoptive Treg therapy may be used for immunomodulation in islet xenotransplantation by minimizing systemic immunosuppression.

Increase in Peripheral Blood Intermediate Monocytes is Associated with the Development of Recent-Onset Type 1 Diabetes Mellitus in Children.

Monocytes play important roles in antigen presentation and cytokine production to achieve a proper immune response, and are therefore largely implicated in the development and progression of autoimmune diseases. The aim of this study was to analyze the change in the intermediate (CD14+CD16+) monocyte subset in children with recent-onset type 1 diabetes mellitus (T1DM) and its possible association with clinical parameters reflecting islet β-cell dysfunction. Compared with age- and sex-matched healthy controls, intermediate monocytes were expanded in children with T1DM, which was positively associated with hemoglobin A1C and negatively associated with serum insulin and C-peptide. Interestingly, the intermediate monocytes in T1DM patients expressed higher levels of human leukocyte antigen-DR and CD86, suggesting better antigen presentation capability. Further analysis revealed that the frequency of CD45RO+CD4+ memory T cells was increased in the T1DM patients, and the memory T cell content was well correlated with the increase in intermediate monocytes. These results suggest that expanded intermediate monocytes are a predictive factor for the poor residual islet β-cell function in children with recent-onset T1DM.

Immunogenicity of hepatic differentiated human umbilical cord mesenchymal stem cells promoted by porcine decellularized liver scaffolds.

Cell-based approaches, including hepatocyte transplantation and tissue-engineered livers, offer promising alternatives and are expected to help support patients with liver diseases until liver transplantation or recovery via regeneration of the damaged liver. However, the success of cell therapies remains dependent on how well the cells are accepted after transplantation and is directly related to their degree of immunogenicity. In this study, hepatic differentiation of human umbilical cord mesenchymal stem cells (hUC-MSCs) was induced in the traditional monolayer (2D) culture and newly established three-dimensional (3D) aggregation culture with the porcine decellularized liver scaffold (DLS) system (3D-DLS). We investigated the immunogenicity of these hepatocyte-like cells in vitro. We found that monolayer hepatic differentiated hUC-MSCs expressed higher levels of human leukocyte antigen-DR (HLA-DR) (P<.05) and lost the ability to inhibit lymphocyte proliferation (P<.05), in association with a lower level of prostaglandin E2 (PGE2 ) (P<.05) and a higher level of interferon-γ (IFN-γ) (P<.05) secretion, compared to undifferentiated hUC-MSCs. The hepatocyte-like cells differentiated in the 3D-DLS system did not show an elevation of MHC-II (P>.05), or cause obvious lymphocytes proliferation, and demonstrated more PGE2 (P<.05) and less IFN-γ (P<.05) secretion. Hepatocyte-like cells in the 3D-DLS system presented a lower immunogenic phenotype than the 2D culture in vitro. Hepatocyte-like cells in 3D-DLS system also performed a higher immunosuppressive capacity than 2D culture.

Dynamic monitoring of monocyte HLA-DR expression for the diagnosis, prognosis, and prediction of sepsis.

Sepsis, an under-recognized health problem, is a major cause of death. More than 750,000 individuals develop sepsis annually, of whom 215,000 die of the disease. Clinical and experimental evidence indicates that patients with sepsis present with rapid impairment of immune function; biomarkers are therefore needed to enable early detection of this condition. Reduced monocyte human leukocyte antigen-DR (HLA-DR) expression, which is measured by flow cytometry, is currently the most popular biomarker for sepsis detection. In addition, the determination of HLA-DR expression provides valuable information in terms of predicting mortality and risk of secondary infections. HLA-DR levels have been shown to be inversely correlated with the severity of sepsis and immune dysfunction. In this review, we provide an overview of the association between sepsis and HLA-DR expression in terms of the predictive value of the latter in sepsis.

Postprandial Monocyte Activation in Individuals With Metabolic Syndrome.

Postprandial hyperlipidemia has been suggested to contribute to atherogenesis by inducing proinflammatory changes in monocytes. Individuals with metabolic syndrome (MS), shown to have higher blood triglyceride concentration and delayed triglyceride clearance, may thus have increased risk for development of atherosclerosis. Our objective was to examine fasting levels and effects of a high-fat meal on phenotypes of monocyte subsets in individuals with obesity and MS and in healthy controls. Design, Setting, Participants, Intervention: Individuals with obesity and MS and gender- and age-matched healthy controls were recruited. Blood was collected from participants after an overnight fast (baseline) and at 3 and 5 hours after ingestion of a high-fat meal. At each time point, monocyte phenotypes were examined by multiparameter flow cytometry. Baseline levels of activation markers and postprandial inflammatory response in each of the three monocyte subsets were measured. At baseline, individuals with obesity and MS had higher proportions of circulating lipid-laden foamy monocytes than controls, which were positively correlated with fasting triglyceride levels. Additionally, the MS group had increased counts of nonclassical monocytes, higher CD11c, CX3CR1, and human leukocyte antigen-DR levels on intermediate monocytes, and higher CCR5 and tumor necrosis factor-α levels on classical monocytes in the circulation. Postprandial triglyceride increases in both groups were paralleled by upregulation of lipid-laden foamy monocytes. MS, but not control, subjects had significant postprandial increases of CD11c and percentages of IL-1β+ and tumor necrosis factor-α+ cells in nonclassical monocytes. Compared to controls, individuals with obesity and MS had increased fasting and postprandial monocyte lipid accumulation and activation.

Characterisation of synovial fluid and infrapatellar fat pad derived mesenchymal stromal cells: The influence of tissue source and inflammatory stimulus

The infrapatellar fat pad (FP) and synovial fluid (SF) in the knee serve as reservoirs of mesenchymal stromal cells (MSCs) with potential therapeutic benefit. We determined the influence of the donor on the phenotype of donor matched FP and SF derived MSCs and examined their immunogenic and immunomodulatory properties before and after stimulation with the pro-inflammatory cytokine interferon-gamma (IFN-γ). Both cell populations were positive for MSC markers CD73, CD90 and CD105, and displayed multipotency. FP-MSCs had a significantly faster proliferation rate than SF-MSCs. CD14 positivity was seen in both FP-MSCs and SF-MSCs, and was positively correlated to donor age but only for SF-MSCs. Neither cell population was positive for the co-stimulatory markers CD40, CD80 and CD86, but both demonstrated increased levels of human leukocyte antigen-DR (HLA-DR) following IFN-γ stimulation. HLA-DR production was positively correlated with donor age for FP-MSCs but not SF-MSCs. The immunomodulatory molecule, HLA-G, was constitutively produced by both cell populations, unlike indoleamine 2, 3-dioxygenase which was only produced following IFN-γ stimulation. FP and SF are accessible cell sources which could be utilised in the treatment of cartilage injuries, either by transplantation following ex-vivo expansion or endogenous targeting and mobilisation of cells close to the site of injury.

Emerging roles of myeloid derived suppressor cells in hepatic inflammation and fibrosis.

Myeloid derived suppressor cells (MDSC) are a heterogeneous population of immune cells that are potent suppressors of immune responses. MDSC emerge in various compartments in the body, such as blood, bone marrow or spleen, especially in conditions of cancer, infections or inflammation. MDSC usually express CD11b, CD33, and low levels of human leukocyte antigen-DR in humans or CD11b and Gr1 (Ly6C/G) in mice, and they can be further divided into granulocytic or monocytic MDSC. The liver is an important organ for MDSC induction and accumulation in hepatic as well as extrahepatic diseases. Different hepatic cells, especially hepatic stellate cells, as well as liver-derived soluble factors, including hepatocyte growth factor and acute phase proteins (SAA, KC), can promote the differentiation of MDSC from myeloid cells. Importantly, hepatic myeloid cells like neutrophils, monocytes and macrophages fulfill essential roles in acute and chronic liver diseases. Recent data from patients with liver diseases and animal models linked MDSC to the pathogenesis of hepatic inflammation, fibrosis and hepatocellular carcinoma (HCC). In settings of acute hepatitis, MDSC can limit immunogenic T cell responses and subsequent tissue injury. In patients with chronic hepatitis C, MDSC increase and may favor viral persistence. Animal models of chronic liver injury, however, have not yet conclusively clarified the involvement of MDSC for hepatic fibrosis. In human HCC and mouse models of liver cancer, MDSC are induced in the tumor environment and suppress anti-tumoral immune responses. Thus, the liver is a primary site of MDSC in vivo, and modulating MDSC functionality might represent a promising novel therapeutic target for liver diseases.

The influence of sex hormones on human leukocyte antigen-DR, soluble myeloid cell receptor-1 and prognosis in patients with severe intra-abdominal infection

To evaluate the influence of serum estradiol, prolactin and testosterone levels on human leukocyte antigen-DR (HLA-DR), soluble myeloid cell receptor-1 (sTREM-1) and prognosis in patients with severe abdominal infection, in order to evaluate the clinical value of the above-mentioned sex hormones. From July 10, 2009 to February 9, 2010, 73 cases with severe intra-abdominal infections hospitalized in surgical intensive care unit (ICU) of Tianjin Nankai Hospital were enrolled. Within 72 hours after enrollment, serum estradiol, prolactin and testosterone levels were detected by radioimmunoassay. Based on their levels, all the cases were divided into increased estradiol group (n=38) and non-increased estradiol group (n=35), increased prolactin group (n=28) and non-increased prolactin group (n=45), decreased testosterone group (n=33) and non-decreased testosterone group (n=40) respectively. In addition, HLA-DR (flow cytometry), as well as of sTREM-1 (enzyme linked immunosorbent assay), acute physiology and chronic health evaluation II (APACHEII) score, hospital days, the ICU length, hospital costs and 28 day mortality were recorded. Compared with non-increased estradiol group, HLA-DR in increased estradiol group decreased significantly [(61.22±22.39)% vs. (75.09±14.85)%], while sTREM-1 (ng/L) increased obviously (291.59±148.13 vs. 216.48±124.82), APACHEII score lowered dramatically (11.47±6.88 vs. 15.36±8.79), hospital costs (ten thousands) raised significantly (10.98±8.15 vs 6.25±3.51), ICU length (days) was much shorter (8.56±4.05 vs. 12.17±7.99), and 28 days mortality was significantly lowered (10.00% vs. 32.75%,P<0.05 or P<0.01). Compared with non-increased prolactin group, increased prolactin group had much lower HLA-DR levels [(61.19±21.50)% vs. (72.02±18.49)%], higher sTREM-1 levels (307.92±173.93 vs. 223.01±106.93), at the same time, their cost of hospitalization (7.75±3.52 vs. 11.36±8.24) and ICU stay length (9.14±3.15 vs. 13.24±2.16) were significantly lower (all P<0.05). Compared with non-decreased testosterone group, HLA-DR in decreased testosterone group increased significantly [(74.69±14.72)% vs. (62.24±22.54)%], while sTREM-1 decreased obviously (208.77±77.80 vs. 294.20±169.36), APACHEII score lowered dramatically (10.57±6.97 vs. 15.39±9.46), hospital costs decreased significantly (7.67±3.81 vs. 11.19±8.05), and 28 days mortality lowered significantly (0 vs. 30.14%, P<0.05 or P<0.01). In the early stage of severe intra-abdominal infection, estrogen, prolactin and testosterone levels had powerful influences on immune, inflammation, and prognosis, which may indicated a widespread clinical application.

Activation of Peripheral Blood CD3&lt;sup&gt;+&lt;/sup&gt; T-lymphocytes in Patients With Atrial Fibrillation

Atrial fibrillation (AF) is a common disease with a poorly understood pathophysiological mechanism. Increasing evidence indicates that AF may be associated with immunologic inflammation responses, but it remains unclear whether activation of peripheral blood CD3(+) T-lymphocytes plays a role in the pathogenesis of AF. The aim of this study was to evaluate this phenomenon. Fifty paroxysmal AF patients and 56 persistent AF patients who underwent successful electrical cardioversion were enrolled. The percentages of CD69 and human leukocyte antigen DR (HLA-DR) positive peripheral blood CD3(+) T-lymphocytes, which indicate T-lymphocyte activation, were examined by flow cytometric analysis in the patients and 51 healthy controls. The patient groups had higher levels of CD69 and HLA-DR than the healthy controls. During the 3-month follow-up, 37 patients had recurrence of AF (recurrence group) and 50 patients remained in sinus (sinus group). The CD69 and HLA-DR levels in the sinus group were all significantly down-regulated at follow-up compared with before cardioversion. However, there were no statistically significant differences between the CD69 and HLA-DR levels in the recurrence group at follow-up and before cardioversion. Our findings suggest that activation of peripheral blood CD3(+) T-lymphocytes was associated with AF, and might be a diagnostic or therapeutic marker.

Coronary Intraplaque Hemorrhage Evokes a Novel Atheroprotective Macrophage Phenotype

Intraplaque hemorrhage accelerates atherosclerosis via oxidant stress and contributes to lesion development and destabilization. Normally, macrophages scavenge hemoglobin-haptoglobin (HbHp) complexes via CD163, and this process provokes the secretion of the anti-inflammatory atheroprotective cytokine interleukin (IL)-10. We therefore tested the hypothesis that HbHp complexes may drive monocyte differentiation to an atheroprotective phenotype. Examination of the macrophage phenotype in hemorrhaged atherosclerotic plaques revealed a novel hemorrhage-associated macrophage population (HA-mac), defined by high levels of CD163, but low levels of human leukocyte antigen-DR. HA-mac contained more iron, a pro-oxidant catalyst, but paradoxically had less oxidative injury, measured by 8-oxo-guanosine content. Differentiating monocytes with HbHp complexes reproduced the CD163(high) human leukocyte antigen-DR(low) HA-mac phenotype in vitro. These in vitro HA-mac cells cleared Hb more quickly, and consistently showed less hydrogen peroxide release, highly reactive oxygen species and oxidant stress, and increased survival. Differentiation to HA-mac was prevented by neutralizing IL-10 antibodies, indicating that IL-10 mediates an autocrine feedback mechanism in this system. Nonlinear dynamic modeling showed that an IL-10/CD163-positive feedback loop drove a discrete HA-mac lineage. Simulations further indicated an all-or-none switch to HA-mac at threshold levels of HbHp, and this conversion was experimentally verified. These data demonstrate the creation of a novel atheroprotective (HA-mac) macrophage subpopulation in response to intraplaque hemorrhage and raise the possibility that therapeutically reproducing this macrophage phenotype may be cardio-protective in cases of atherosclerosis.

Preoperative high-dose steroid administration attenuates the surgical stress response following liver resection: results of a prospective randomized study

Major abdominal surgery such as liver resection is associated with an excessive hyperinflammatory response and transient immunosuppression. We investigated the immunomodulating effect of preoperative pulse administration of high-dose methylprednisolone in patients undergoing hepatic resection without pedicle clamping. Twenty patients who underwent hepatic resection were randomized into two groups: a steroid group (n = 10), in which patients were given 30 mg/kg per body weight (BW) methylprednisolone intravenously, and a control group (n = 10), in which patients received a placebo (sodium chloride) infusion. The main outcome parameter to assess systemic stress was the serum plasma level of interleukin-6 (IL-6). To evaluate cell-mediated immune function, human leukocyte antigen-DR (HLA-DR) expression on peripheral blood monocytes and lipopolysaccharide (LPS)-induced tumor necrosis factor-alpha (TNF-alpha) release by peripheral monocytes was measured. Other investigated serum parameters included C-reactive protein (CRP), total bilirubin, alanine aminotransferase (ALT), prothrombin time (PT)-INR, and cytokines such as IL-8 and IL-10 and TNF-alpha. Postoperative convalescence, complication rate, and length of hospital stay were compared between the groups. Postoperative plasma concentrations of IL-6 (days 1 and 2), IL-8 (days 2 and 3), and CRP (days 1-4) were significantly lower in the steroid than in the control group. The total bilirubin concentration was significantly lower on day 6 in the steroid than in the control group. Four hours after surgery, LPS-induced TNF-alpha secretion was significantly reduced in the steroid group, but it increased rapidly during the following days. HLA-DR, ALT, and PT-INR levels were not different between the two groups. The postoperative hospital stay in the steroid group was significantly lower compared to that in the control group (mean, 10.5 days versus 14.8 days; P < 0.05). No differences were found in the convalescence score or postoperative complication rate. Intravenous methylprednisolone administration before hepatic resection significantly reduced systemic inflammatory cytokine release. No adverse effect on immunity was noted due to the methylprednisolone. We found no significant difference in the convalescence score, but a significantly shorter hospital stay in the steroid group. Further studies with more patients are needed to elucidate the clinical impact of preoperative steroid bolus therapy in liver surgery.

Differential capability for phagocytosis of apoptotic and necrotic leukemia cells by human peripheral blood dendritic cell subsets

CD11c+ dendritic cells (DC) and plasmacytoid DC (PDC) are the two major DC subsets in human peripheral blood. For the purpose of immunotherapy with DC, it is important to investigate the phagocytosis of killed tumor cells by different DC subsets. Using immature monocyte-derived DC (iMoDC) as reference, we have compared the ability of CD11c+ DC and PDC to phagocytose apoptotic and necrotic K562 leukemia cells. Freshly isolated CD11c+ DC phagocytosed apoptotic and necrotic K562 cells, whereas PDC did not show any evidence of uptake of dead cells. Blocking studies showed that CD36 is importantly involved in uptake of apoptotic and necrotic material. CD91 and CD11c were also involved. In addition, we found that beta5 integrin was expressed on CD11c+ DC but not in its classical association with alphaV. Uptake of apoptotic K562 cells by CD11c+ DC was increased following incubation with granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin (IL)-4, alone or in combination with transforming growth factor-beta1, to levels comparable with those observed for iMoDC. Phagocytosis of dead cellular material by the GM-CSF/IL-4-treated CD11c+ DC was largely restricted to a subset expressing low levels of human leukocyte antigen-DR and CD83. Thus, the relationship between phagocytosis of antigenic material and expression of maturation-related cell-surface molecules is similar for CD11c+ DC and MoDC. We conclude that CD11c+ DC in peripheral blood are precursor cells, which under the influence of cytokines, differentiate to cells with DC phenotype and function.

Human leukocyte antigen‐DR expression on peripheral blood monocytes and the risk of pneumonia in pediatric lung transplant recipients

Pneumonia is the leading cause of morbidity and mortality after living lobar lung transplantation (LT). Low levels of human leukocyte antigen-DR (HLA-DR) expression on peripheral blood monocytes, have been demonstrated to correlate with risk of infection in surgical, trauma, and adult transplant patients. In addition, interleukin (IL)-10 has been shown to be a negative regulator of HLA-DR expression. This study investigates whether HLA-DR expression and serum IL-10 levels correlate with the development of pneumonia after pediatric LT. Thirteen LT recipients were prospectively monitored with blood samples obtained pre-LT (baseline) and post-LT weeks 1-4. Mean fluorescence intensity (MFI) of HLA-DR on CD14+ monocytes was measured by flow cytometry. IL-10 levels were determined by ELISA from frozen serum collected at the same time points as monocyte HLA-DR expression. Correlates of pneumonia were abstracted from the medical record. Monocyte HLA-DR expression declined in 11 of 13 patients in the first week post-LT. Two patients without an initial decline and four others whose HLA-DR expression recovered by week 2 post-LT, did not develop pneumonia or other infection or rejection. Pneumonia was observed in seven patients, six of whom failed to recover their monocyte HLA-DR expression by 2 weeks post-LT. Six of seven patients with pneumonia recovered, and one patient died of aspergillosis. During weeks 1-4, a statistically significant difference was seen in the profile of mean monocyte HLA-DR expression levels, analyzed as percent of baseline, between the patients with and without pneumonia (P=0.002). The greatest difference between groups over time was seen from post-LT weeks 1-2 (P=0.003). In addition, when comparing the values at each week, a significant difference was seen between the two groups at post-LT week 2 (P=0.006) and week 4 (P=0.05). Analysis of IL-10 concentrations revealed that the overall difference between the groups (patients with and without pneumonia) was statistically significant (P=0.014), with a paradoxical positive correlation between HLA-DR expression at post-LT week 4 and IL-10 concentrations. Persistent low monocyte HLA-DR expression was associated with the risk of post-LT pneumonia in these patients. This measurement may be useful for monitoring risk of infection and stratifying patients into higher and lower risk groups. Increased IL-10 levels may be protective for infection in this group of patients. At present it is unknown whether the predictive power of HLA-DR expression is indicative of a global defect in monocytic function or a specific abnormality.

Selective Action of the Photosensitizer QLT0074 on Activated Human T Lymphocytes¶

A new photosensitizer, presently designated QLT0074, may have the potential for the treatment of immune and nonimmune conditions with photodynamic therapy (PDT). The activity of QLT0074 was tested against human peripheral blood T cells and Jurkat T lymphoma cells. At low nanomolar concentrations of QLT0074 in combination with blue light, apoptosis was rapidly induced in Jurkat and blood T cells in vitro as indicated by the expression of the apoptosis-associated mitochondrial 7A6 marker and Annexin-V labeling. Further studies performed with Jurkat T cells showed that PDT-induced apoptosis with QLT0074 was associated with caspase-3 activation and the cleavage of the caspase substrate poly(adenosine diphosphate–ribose)polymerase. Flow cytometry studies revealed that blood T cells with high expression of the interleukin-2 receptor (CD25) took up greater amounts of QLT0074 and were eliminated to a greater extent with PDT than T cells with low levels of this activation marker. This selective action of PDT was confirmed by similar reductions in the percentage of T cells that expressed other activation-related markers, including very late activation antigen-4 (CD49d), human leukocyte antigen DR (HLA-DR), intercellular adhesion molecule-1 (CD54) and Fas (CD95). For activated T cells treated with a specific dose of QLT0074 and light 24 h earlier, CD25 expression density was significantly less, whereas CD54, CD95 and HLA-DR levels were similar to those for control cells treated with light alone. This work shows that PDT with QLT0074 exerts selective, dose-related effects on T cells in vitro.

Selective action of the photosensitizer QLT0074 on activated human T lymphocytes.

A new photosensitizer, presently designated QLT0074, may have the potential for the treatment of immune and nonimmune conditions with photodynamic therapy (PDT). The activity of QLT0074 was tested against human peripheral blood T cells and Jurkat T lymphoma cells. At low nanomolar concentrations of QLT0074 in combination with blue light, apoptosis was rapidly induced in Jurkat and blood T cells in vitro as indicated by the expression of the apoptosis-associated mitochondrial 7A6 marker and Annexin-V labeling. Further studies performed with Jurkat T cells showed that PDT-induced apoptosis with QLT0074 was associated with caspase-3 activation and the cleavage of the caspase substrate poly(adenosine diphosphate-ribose)polymerase. Flow cytometry studies revealed that blood T cells with high expression of the interleukin-2 receptor (CD25) took up greater amounts of QLT0074 and were eliminated to a greater extent with PDT than T cells with low levels of this activation marker. This selective action of PDT was confirmed by similar reductions in the percentage of T cells that expressed other activation-related markers, including very late activation antigen-4 (CD49d), human leukocyte antigen DR (HLA-DR), intercellular adhesion molecule-1 (CD54) and Fas (CD95). For activated T cells treated with a specific dose of QLT0074 and light 24 h earlier, CD25 expression density was significantly less, whereas CD54, CD95 and HLA-DR levels were similar to those for control cells treated with light alone. This work shows that PDT with QLT0074 exerts selective, dose-related effects on T cells in vitro.

A randomized prospective clinical trial to determine the efficacy of interferon-γ in severely injured patients

Many aspects of the normal immune response are depressed after severe injury. Reduced monocyte human leukocyte antigen-DR (HLA-DR) levels have closely correlated with the development of major infection. After a pilot study with recombinant interferon-γ (rIFN-γ) showed restoration of depressed HLA-DR levels after major injury, a multicenter, prospective, randomized, double-blind trial was conducted. Two hundred thirteen trauma patients who were at high risk of infection received either placebo or rIFN-γ (100 μg) subcutaneously each day for 10 days after admission. One hundred ninety-three patients were evaluable with respect to primary end points. Patients treated with rIFN-γ were older (p = 0.10) and had more severe modes of injury (p = 0.02). By the third day, both monocyte HLA-DR antigen expression and outcome predictive score were significantly better in the rIFN-γ-treated group than in the placebo group (p = 0.0001 and p = 0.0006, respectively). Nine deaths occurred in patients treated with rIFN-γ compared with 12 deaths in the placebo group (p = 0.46). Major infections requiring surgical drainage or dé-bridement occurred in 17 patients treated with rIFN-γ compared with 22 treated with placebo. No difference between treatment arms was noted in overall major or minor infection rates, but there were fewer severe infections that required reoperation or computer tomographic-guided drainage in patients receiving IFN-γ. While these results suggest that rIFN-γ may be useful in some aspects of infection in the patient with severe trauma, a larger trial with longer treatment will be needed to prove the comprehensive value of rIFN-γ.