Endotoxin fever in granulocytopenic rats: evidence that brain cyclooxygenase-2 is more important than circulating prostaglandin E(2)

PGE(2) is a recognized mediator of many fevers, and cyclooxygenase (COX) is the major therapeutic target for antipyretic therapy. The source, as well as the site of action of PGE(2), as an endogenous pyrogen, is widely accepted as being central, but PGE(2) in the circulation, possibly from leukocytes, may also contribute to the development of fever. However, bacterial infections are important causes of high fever in patients receiving myelosuppressive chemotherapy, and such fevers persist despite the use of COX inhibitors. In the study reported here, the febrile response to bacterial LPS was measured in rats made leukopenic by cyclophosphamide. A striking increase in LPS fever occurred in these granulocytopenic rats when compared with febrile responses in normal animals. Unlike LPS fever in normal rats, fever in granulocytopenic rats was neither accompanied by an increase in blood PGE(2) nor inhibited by ibuprofen. Both leukopenic and normal rats showed LPS-induced COX-2-immunoreactivity in cells associated with brain blood vessels. Furthermore, LPS induced an increase of PGE(2) in cerebrospinal fluid. Induction of COX-2-expression and PGE(2) production was inhibited by ibuprofen in normal but not in leukopenic rats. Although the results presented are, in part, confirmatory, they add new information to this field and open a number of important questions as yet unresolved. Overall, the present results indicate that, in contrast to immunocompetent rats, leukocytes and/or other mechanisms other than PGE(2) are implicated in the mechanisms restricting and reducing the enhanced febrile response to endotoxin in immunosuppressed hosts.     

Endothelial cells are main producers of interleukin 8 through Toll-like receptor 2 and 4 signaling during bacterial infection in leukopenic cancer patients

Cancer patients who are leukopenic due to chemotherapy are susceptible to bacterial infections. Normally, clinical conditions during bacterial infections are caused by pathogen-associated molecular patterns, which are components that bind to Toll-like receptor (TLR) 2 (TLR-2) and TLR-4 on leukocytes, resulting in the production of inflammatory cytokines. The mechanism of this inflammatory response in cancer patients with diminished numbers of leukocytes is not completely clear. The levels of interleukin 1 beta (IL-1 beta) and tumor necrosis factor alpha measured in the circulation of leukopenic cancer patients are lower than those measured in that of nonleukopenic patients during bacterial infections, whereas plasma interleukin 8 (IL-8) levels show distinct identical increases during bacterial infections in both leukopenic and nonleukopenic patients. Normally, these cytokines are mainly secreted by leukocytes. In cancer patients with bacterial infections and a diminished number of leukocytes, other sources of IL-8 production, such as endothelial cells, might be expected. Endothelial cells instead of leukocytes become the most important producers of IL-8 during bacterial infections in patients with chemotherapy-induced leukopenia through TLR-2 and TLR-4 signaling. Whole blood samples from six cancer patients were stimulated with lipopolysaccharide (LPS), and then IL-8 concentrations in supernatants were measured. Further, human umbilical vein endothelial cells (HUVECs) were incubated with sera from leukopenic cancer patients with or without bacterial infections, and then IL-8 concentrations in supernatants were measured (n = 6). In addition, the same HUVEC experiment was performed with the addition of neutralizing antibodies against TLR-2 and TLR-4. During leukopenia (<10(9) cells/liter), LPS stimulation of whole blood did not result in an increase in IL-8 levels. However, when endothelial cells were incubated with sera from leukopenic cancer patients during bacterial infections, a three- to eightfold increase in IL-8 production was found, compared to the IL-8 production found after incubation with sera from patients without signs of infections. This increase did not reflect a higher level of IL-8 already present in the sera. Further, we demonstrated that IL-8 production induced in endothelial cells by sera from patients with documented gram-negative infections could be reduced significantly by up to 40% when the cells were incubated with neutralizing antibodies against TLR-4 (P = 0.028). The addition of TLR-2 antibodies slightly enhanced the reduction of IL-8 production. These results suggest that during bacterial infections in cancer patients with markedly diminished numbers of leukocytes, endothelial cells become important producers of IL-8 through TLR-4 signaling and, to a lesser extent, TLR-2 signaling.     

Endothelial Cells Are Main Producers of Interleukin 8 through Toll-Like Receptor 2 and 4 Signaling during Bacterial Infection in Leukopenic Cancer Patients

Cancer patients who are leukopenic due to chemotherapy are susceptible to bacterial infections. Normally, clinical conditions during bacterial infections are caused by pathogen-associated molecular patterns, which are components that bind to Toll-like receptor (TLR) 2 (TLR-2) and TLR-4 on leukocytes, resulting in the production of inflammatory cytokines. The mechanism of this inflammatory response in cancer patients with diminished numbers of leukocytes is not completely clear. The levels of interleukin 1β (IL-1β) and tumor necrosis factor alpha measured in the circulation of leukopenic cancer patients are lower than those measured in that of nonleukopenic patients during bacterial infections, whereas plasma interleukin 8 (IL-8) levels show distinct identical increases during bacterial infections in both leukopenic and nonleukopenic patients. Normally, these cytokines are mainly secreted by leukocytes. In cancer patients with bacterial infections and a diminished number of leukocytes, other sources of IL-8 production, such as endothelial cells, might be expected. Endothelial cells instead of leukocytes become the most important producers of IL-8 during bacterial infections in patients with chemotherapy-induced leukopenia through TLR-2 and TLR-4 signaling. Whole blood samples from six cancer patients were stimulated with lipopolysaccharide (LPS), and then IL-8 concentrations in supernatants were measured. Further, human umbilical vein endothelial cells (HUVECs) were incubated with sera from leukopenic cancer patients with or without bacterial infections, and then IL-8 concentrations in supernatants were measured (n = 6). In addition, the same HUVEC experiment was performed with the addition of neutralizing antibodies against TLR-2 and TLR-4. During leukopenia (<10⁹ cells/liter), LPS stimulation of whole blood did not result in an increase in IL-8 levels. However, when endothelial cells were incubated with sera from leukopenic cancer patients during bacterial infections, a three- to eightfold increase in IL-8 production was found, compared to the IL-8 production found after incubation with sera from patients without signs of infections. This increase did not reflect a higher level of IL-8 already present in the sera. Further, we demonstrated that IL-8 production induced in endothelial cells by sera from patients with documented gram-negative infections could be reduced significantly by up to 40% when the cells were incubated with neutralizing antibodies against TLR-4 (P = 0.028). The addition of TLR-2 antibodies slightly enhanced the reduction of IL-8 production. These results suggest that during bacterial infections in cancer patients with markedly diminished numbers of leukocytes, endothelial cells become important producers of IL-8 through TLR-4 signaling and, to a lesser extent, TLR-2 signaling.     

Endogenous Interleukin-10 is Required for the Defervescence of Fever Evoked by Local Lipopolysaccharide-Induced and Staphylococcus Aureus-Induced Inflammation in Rats

We tested the hypothesis that endogenous interleukin (IL)-10 limits the fever induced by a Gram-negative bacterial toxin ( Escherichia coli lipopolysaccharide, LPS) and a Gram-positive bacterial toxin ( Staphylococcus aureus ), when these toxins are injected into a subcutaneous air pouch ( i.po .) in rats. Injection of LPS or S. aureus caused fevers that were reduced in amplitude and duration by simultaneous administration of rat recombinant IL-10. The inhibition of fever by IL-10 was accompanied by a significant reduction in the toxin-evoked increases in concentrations of immunoreactive IL-6 at the site of inflammation and of IL-6 and IL-1 receptor antagonist in the circulation. Conversely, neutralisation of endogenous IL-10 in the pouch increased the amplitude and dramatically increased the duration of toxin-evoked fever, and augmented toxin-induced increases in pouch tumour necrosis factor-α, IL-1β, and especially IL-6. Our data support a crucial regulatory role for endogenous IL-10 in limiting the fever responses during both Gram-negative and Gram-positive infections.     

Otomicroscopic findings and systemic interleukin-6 levels in relation to etiologic agent during experimental acute otitis media

The aim of the present study was to explore whether it was possible to differentiate the clinical course and the otomicroscopic appearance of acute otitis media (AOM) caused by common otitis pathogens in an animal model. Systemic interleukin (IL)-6 levels as early markers for bacterial AOM were also studied. Four groups of rats were inoculated with either Streptococcus pneumoniae, Streptococcus pyogenes, non-typeable Haemophilus influenzae or Moraxella catarrhalis. The animals were monitored by otomicroscopy, photos of the tympanic membrane, cultures and IL-6 detection in serum the following 4 days. The gram-positive S. pneumoniae and S. pyogenes induced severe AOM with opaque effusion behind the tympanic membrane, pronounced dilation of the vessels and spontaneous perforations. The gram-negative H. influenzae and M. catarrhalis induced a less severe infection with cloudy, sometimes foamy effusion, and no spontaneous perforations. With the otomicroscopic findings it was possible to distinguish between infections induced by gram-positive bacteria and gram-negative bacteria. Detection of interleukin-6 in serum appeared to be of limited use for all infections except the pneumococcal AOM, but this needs to be further investigated.     

支原体肺炎与细菌性肺炎炎性指标及血清降钙素原水平比较

目的 分析血清炎性细胞因子、血清降钙素原（PCT）、C反应蛋白（CRP）在支原体肺炎与细菌性肺炎中的水平变化及临床意义。方法 回顾分析2018年1月~2019年1月在我院诊治的90例儿童肺炎临床资料,其中诊断为支原体肺炎的51例设为观察A组,细菌性肺炎39例设为观察B组,另选取同期健康儿童40例设为对照组,比较各组血清炎性细胞因子（IL-6、IL-10）、PCT、CRP水平以及观察A组和观察B组急性期与缓解期血清PCT、CRP水平。结果 观察A组、观察B组IL-6水平均高于对照组,IL-10水平低于对照组,差异有统计学意义（P＜0.05）,观察A组与观察B组IL-6、IL-10分别比较,差异无统计学意义（P＞0.05）;观察B组PCT水平高于对照组和观察A组,差异有统计学意义（P＜0.05）,观察A组与对照组比较,差异无统计学意义（P＞0.05）;观察A组、观察B组CRP水平均高于对照组,且观察B组高于观察A组,差异有统计学意义（P＜0.05）;观察A组、观察B组急性期血清PCT、CRP 水平均高于缓解期,差异有统计学意义（P＜0.05）。结论 血清IL-6、IL-10、PCT和CRP有助于儿童支原体肺炎和细菌性肺炎的诊断,支原体肺炎和细菌性肺炎患儿炎性细胞因子水平基本相同,而PCT对细菌性肺炎诊断具有良好指导作用,可作为临床诊治中可靠的参考依据。     

Lipoteichoic acid induces secretion of interleukin-8 from human blood monocytes: a cellular and molecular analysis.

Invasion by gram-positive and gram-negative bacterial organisms is characterized immunopathologically by the activation of mononuclear phagocytic cells, leading to the elaboration of macrophage-derived regulatory and chemotactic factors, and the resultant influx of inflammatory leukocytes. Little is known regarding the mechanisms by which gram-positive organisms initiate macrophage activation and subsequent inflammation. In this investigation, we postulated that lipoteichoic acid (LTA) purified from two different gram-positive bacterial species was an important signal for the expression of chemotactic cytokines from human peripheral blood monocytes (PBM). In initial experiments, we demonstrated that cell-associated interleukin-8 (IL-8) was expressed by mononuclear phagocytes present in inflamed areas of endocardium in cases of acute Staphylococcus aureus endocarditis. We next demonstrated that LTA purified from either Staphylococcus aureus or Streptococcus pyogenes induced the time- and dose-dependent expression of IL-8 mRNA and protein from human PBM. The expression of IL-8 mRNA from LTA- but not lipopolysaccharide (LPS)-treated PBM was superinduced by concomitant treatment with cycloheximide, indicating that the expression of IL-8 mRNA from LTA-treated PBM was negatively controlled by repressor proteins. Furthermore, mRNA stability studies indicated that IL-8 mRNA was less stable in the presence of LTA than in the presence of LPS. Our findings indicate that LTA can induce the secretion of the polymorphonuclear leukocyte chemotactic factor IL-8 and that LTA may be an important cellular mediator of inflammatory cell recruitment that characterizes immune responses to gram-positive bacterial infections.     

Markers of bacteremia in febrile neutropenic patients with hematological malignancies: procalcitonin and IL-6 are more reliable than C-reactive protein

Since neutropenic patients with hematological malignancies are at high risk of contracting life-threatening infections, specific markers of infection are needed in cases of febrile neutropenia. The study presented here assessed serum concentrations of C-reactive protein (CRP), procalcitonin (PCT) and interleukin-6 (IL-6) in samples obtained from 31 febrile neutropenic patients. A total of 53 episodes were evaluated, and 18 of these were associated with positive blood culture results. Procalcitonin and IL-6 concentrations differed significantly between bacteremic and non-bacteremic episodes. Procalcitonin values were 0.22 ng/ml [interquartile range (IR), 0.15–1.9] for patients with pneumonia without bacteremia, 0.22 ng/ml (IR, 0.16–0.55) for patients with fever of unknown origin, 0.2 ng/ml (IR, 0.13–0.57) for patients with non-microbial fever and 1.8 ng/ml (IR, 0.35–5.3) for patients with bacteremia. The differences between bacteremic and non-bacteremic episodes had a P-value of 0.003 using the Mann–Whitney test. For IL-6 the median values were 301 pg/ml (IR, 152–1,879) for patients with pneumonia without bacteremia, 207 pg/ml (IR, 94–445) for patients with fever of unknown origin, 177 pg/ml (IR, 142–208) for patients with non-microbial fever and 942 pg/ml (IR, 181–2,807) for patients with bacteremia. Using the Mann–Whitney test, the differences between bacteremic and non-bacteremic episodes were P=0.006. No differences were found in CRP concentrations. Cutoff levels to distinguish between bacteremic and non-bacteremic episodes were chosen using receiver operating characteristic curves: 0.62 ng/ml for PCT and 297 pg/ml for IL-6. Negative predictive values were 84% for PCT and 70% for IL-6. The results indicate that PCT and IL-6 are more reliable markers than CRP for predicting bacteremia in patients with febrile neutropenia.     

Influence of ambient temperature on peripherally induced interleukin-1 beta fever in young and old rats

We have previously demonstrated that old and young rats mount similar fevers after intraperitoneal (i.p.) LPS injection at a warm ambient temperature (Ta) of 31 degrees C, but not at a cooler Ta of 21 degrees C. LPS stimulates the synthesis and release of proinflammatory cytokines, particularly interleukin-1 beta (IL-1 beta), necessary for fever development, and possibly this is attenuated at the lower Ta. If so, then administration of exogenous IL-1 beta should enable old rats to mount fevers equivalent to those of young rats regardless of Ta. Here, young (3-5 months) and old (23-29 months) Long-Evans rats were maintained at Ta 21 or 31 degrees C for 3 days prior to i.p. or intravenous (i.v.) injection of rat recombinant IL-1 beta (1 microg/kg) or vehicle. Three days later, rats were given the alternate injection at the same T(a). At least 5 days later, the same rats were injected at the other Ta. Body temperature was continuously monitored throughout the experiments. Young rats mounted fevers after LPS at both Ta's and i.p. fevers were lower than i.v. fevers. Old rats developed fevers that were equivalent to those of young rats at 31 degrees C regardless of route of administration, but no fever responses were evident at 21 degrees C. These data suggest that the attenuated fever of old rats is not due to an inability to produce IL-1 beta, but rather to a deficiency further along in the fever pathway. In addition, these results show that, as with LPS, Ta plays a role in the ability of old rats to mount fever in response to IL-1 beta.     

C-reactive protein in the diagnosis and management of infections in granulocytopenic and non-granulocytopenic patients

The serum levels of C-reactive protein (CRP) were assayed in 64 non-granulocytopenic and 35 granulocytopenic patients with or without fever and infection. Most patients showed a direct CRP response within 24 hours after onset of fever (95 % of non-granulocytopenic patients, 100 % of granulocytopenic patients). The mean peak level of CRP in febrile patients with septicemia was 207 mg/l (median 214 mg/l) in non-granulocytopenic patients and 173 mg/l (median 168 mg/l) in granulocytopenic patients, and differed significantly (p<0.001) from that in febrile patients without positive blood cultures. A significant difference between patients with major and minor infections was also found (p<0.01). No significant difference in the CRP level was found between patients with microbiologically and clinically documented infections (p>0.05), nor did the serum CRP levels differ between patients with infections due to gram-positive and gram-negative organisms. The most favorable cut-off limit for detection of an inflammatory process in this study was 25 mg/l. There was no quantitative difference between CRP levels measured by a latex-agglutination method and the nephelometry assay.     

血清IL-6、IL-10、CRP和PCT水平检测对手足口病早期 合并细菌感染患儿的临床诊断价值

目的 探讨血清IL-6、IL-10、CRP和PCT水平检测对手足口病早期合并细菌感染患儿的临床诊断价值。方法 选取我院收治的早期手足口病患儿90例为观察组,并根据患儿是否合并细菌感染分为单纯组51例和感染组39例,选取同期来我院体检的健康儿童50例为对照组,比较三组间IL-6、IL-10、CRP和PCT水平差异。结果 观察组患儿IL-6、IL-10、CRP以及PCT水平高于对照组,差异有统计学意义（P＜0.05）;感染组患儿CRP以及PCT水平高于单纯组,差异具有统计学意义（P＜0.05）;感染组和单纯组IL-6、IL-10水平比较,差异无统计学意义（P＞0.05）。结论 IL-6、IL-10水平在鉴别手足口病是否合并细菌感染方面的意义有待于进一步研究,而联合CRP和PCT检测可为临床鉴别早期手足口患儿是否合并细菌感染提供可靠的实验室依据,利于临床早期用药治疗。     

Procalcitonin does not discriminate infection from inflammation after allogeneic bone marrow transplantation

Procalcitonin (PCT) is an early marker of bacterial infection but little is known about its value in neutropenic allogeneic bone marrow transplant (BMT) recipients. We collected plasma from 12 recipients of T-cell-depleted HLA-matched related BMT recipients who had been treated preemptively with meropenem from the day after BMT for at least 15 days. PCT and C-reactive protein (CRP) concentrations were determined on BMT days 1, 5, 8, 12, and 15, and their relationship to inflammatory events (IE), including mucositis, microbiologically and clinically defined infections, acute graft-versus-host disease (GVDH), and unexplained fever, was then determined. The PCT concentrations were all low and never exceeded 4 microg/liter, unlike CRP concentrations, which spanned the full range up to 350 mg/liter. All patients had mucositis, and there was no significant difference between PCT concentrations associated with mucositis alone and those associated with an additional IE on BMT days 1 to 12. However, on BMT day 15, the mean concentrations of PCT were 0.37 +/- 0.05 microg/liter for the 10 patients that had an additional IE, compared with 0.11 +/- 0.03 microg/liter for the 2 patients with mucositis only (P = 0.012), and GVHD rather than infection was involved in six cases. PCT was also not a sensitive marker of gram-positive bacteremia or pulmonary aspergillosis. Thus, PCT is of little value in discriminating infections from other inflammatory complications that occur following allogeneic BMT.     

Usefulness of serum procalcitonin measurement in the diagnosis of bacterial infection in patients with systemic autoimmune diseases

Procalcitonin (PCT), a precursor for calcitonin, has been reported to be elevated in bacterial infection. However, its significance in the diagnosis of bacterial infection in patients with systemic autoimmune diseases, who have treatment with corticosteroid and immunosuppressive drug, is limited. To investigate the usefulness of serum procalcitonin measurement in the diagnosis of bacterial infection in patients with systemic autoimmune diseases, we analyzed 28 patients with systemic autoimmune diseases hospitalized because of fever and/or C-reactive protein (CRP) elevation. PCT was measured by the immunochromatography assay. Fourteen patients were considered having bacterial infections and the other 14 patients were considered having disease flare of their systemic autoimmune diseases. Serum CRP levels in the bacterial infection group was higher than that in the systemic autoimmune disease flare group; however, the difference did not reach statistical significance. The positive rate of serum PCT was significantly higher in the bacterial infection group (10/14, 71%) than that in the systemic autoimmune disease flare group (1/14, 7%), although there were 2 cases showing false positive PCT probably due to rheumatoid factor. This study suggested that PCT is useful in the diagnosis of bacterial infection in patients with systemic autoimmune diseases who are treated with corticosteroid and immunosuppressive drug.     

血清IL-6、CRP和PCT水平对严重多发伤后MODS的预测价值

目的探讨多发伤患者外周血血清白细胞介素-6(IL-6)、C反应蛋白(CRP)和降钙素原(PCT)对多器官功能障碍综合征(MODS)的预测价值。方法 87例多发伤患者按治疗过程中有无发生MODS分为MODS组和非MODS组。采用ELISA法测定患者伤后第1、2、3、5、和7天血清IL-6和PCT的含量,采用免疫比浊法测定血清CRP的水平,并与20例健康对照比较,应用受试者工作特征曲线(ROC曲线)进行统计学分析。结果与健康对照组相比,多发伤患者血清IL-6、CRP和PCT水平伤后早期均出现不同程度的升高(P<0.01),其中PCT水平升高最早;与非MODS组比较,MODS组各项指标均有显著差异(P<0.01)。IL-6、CRP和PCT的ROC曲线下面积分别为0.686、0.854和0.914。PCT对严重多发伤后发生MODS的诊断价值高于IL-6和CRP。结论 PCT是严重多发伤后预测MODS发生的较好辅助诊断指标,其诊断价值优于IL-6和CRP。     

Assay for determination of the serum procalcitonin level: biochemical and clinical evaluation

In patients with inflammatory conditions such as infection, cytokines induce the production of C-reactive protein(CRP) and serum amyloid A protein(SAA) in hepatic cells. It has been reported that upon viral infection, the serum SAA level increases by a greater degree than the serum CRP level. Procalcitonin (PCT), the precursor of calcitonin, is a new type of inflammatory marker that is specifically induced by bacterial infection, sepsis and lethal multiple organ failure, but not by viral infection, autoimmune diseases, tumors or surgical stress. To evaluate the immunoluminometric assay(LUMI test PCT; Brahms Diagnostics, Berlin, Germany) procedure for determining the PCT level and to study the clinical significance of the serum PCT level, we determined the serum levels of PCT, CRP and SAA in patients with various inflammatory diseases and normal subjects. The serum PCT level in the normal subjects was < 0.3 ng/ml. Among the patients with inflammatory disease who had a high CRP level(CRP > 20000 micrograms/dl), the PCT level was elevated only in those patients with severe bacterial infection. These results suggest that determining the PCT level may be useful in the differential diagnosis of severe bacterial infection. The patients who had a low CRP level(CRP < 150 micrograms/dl), had a PCT level within the normal range. The patients with autoimmune disease, viral infection, and fungal infection did not have an elevated PCT level.     

The phosphatidylinositol 3-kinase/protein kinase B signaling pathway is activated by lipoteichoic acid and plays a role in Kupffer cell production of interleukin-6 (IL-6) and IL-10

Sepsis caused by gram-positive bacteria lacking lipopolysaccharide (LPS) has become a major and increasing cause of mortality in intensive-care units. We have recently demonstrated that the gram-positive-specific bacterial cell wall component lipoteichoic acid (LTA) stimulates the release of the proinflammatory cytokines in Kupffer cells in culture. In the present study, we have started to assess the signal transduction events by which LTA induces the production of tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), and the anti-inflammatory cytokine IL-10 in rat Kupffer cells. LTA was found to trigger phosphorylation of mitogen-activated protein kinases (MAPK) (p38 MAPK and ERK 1/2) and protein kinase B (PKB). Compared to LPS, LTA was more potent in inducing PKB phosphorylation after 40 min, although we found that the cytokine responses were similar. For both bacterial molecules, blocking phosphatidylinositol 3-kinase (PI3-K; Ly294002) or Janus kinase 2 (JAK-2; AG490) particularly affected the induction of IL-6 and IL-10 release, whereas TNF-alpha levels were strongly reduced by inhibition of Src family tyrosine kinases (PP2). All three cytokines were reduced by inhibition of p38 MAPK (SB202190) or the broad-range tyrosine kinase inhibitor genistein, whereas IL-6 release was particularly blocked by inhibition of ERK 1/2 (PD98059). Divergences in the regulatory pathways controlling TNF-alpha, IL-10, and IL-6 production in Kupffer cells following LPS or LTA stimulation may create a basis for understanding how the balance between pro- and anti-inflammatory cytokines is regulated in the liver following infections by gram-positive or gram-negative bacteria.     

Blocking NF-kappaB activation may be an effective strategy in the fever therapy

Lipopolysaccharide (LPS) stimulates peripheral mononuclear cells (PBMC) to synthesize or release pyrogenic cytokines, including interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor-alpha (TNF-alpha). Nuclear factor-kappa B (NF-kappaB) influences inflammatory responses through the regulation of genes encoding cytokines. In the present study, experiments were carried out to determine whether an inhibition of NF-kappaB mechanisms causes an inhibition of pyrogenic cytokine synthesis or release from PBMC and results in antipyresis. Intravenous administration of the supernatant fluids obtained from the human PBMC incubated with LPS caused feverlike hyperthermia in rabbits. The febrile responses were in parallel with the levels of IL-1beta, IL-6, and TNF-alpha in supernatant fluids. Both the fever and the increased levels of these cytokines in supernatant fluids were decreased by incubating LPS-PBMC with NF-kappaB inhibitors, including pyrrolidine dithiocarbamate, sodium pyrithione, N-acetyl-cysteine, and curcumin. Moreover, an intravenous administration of LPS (0.5-2 microg/kg) produced dose-dependent fever in the rabbits. The fevers were in parallel with the levels of IL-1beta, IL-6, and TNF-alpha in rabbit serum. A pretreatment of rabbits with an intravenous injection of pyrrolidine dithiocarbamate, sodium pryithione, N-acetyl-cysteine, or curcumin 1 h before the intravenous administration of LPS significantly attenuated the LPS-induced fever and/or increased levels of these cytokines in the serum of rabbits. Furthermore, pretreatment with an intravenous dose of anti-IL-1beta, anti-IL-6, or anti-TNF-alpha monoclonal antibody significantly attenuated the fever induced by the intravenous injection of LPS in rabbits. The antipyretic effects exerted by anti-L-1beta monoclonal antibody were greater than those exerted by anti-L-6 or anti-NF-alpha monoclonal antibody. The data indicate that NF-kappaB activation correlates with an LPS-induced synthesis or a release of cytokines (in particular, IL-1beta) from PBMC and triggers fever. Blocking NF-kappaB mechanisms in the PBMC with NF-kappaB inhibitors may be an effective strategy in the fever therapy.     

降钙素原和白介素-6在感染性疾病病原体诊断中的联合检测价值

目的 探讨降钙素原（PCT）与白介素-6（IL-6）两种血清学标志物在感染性疾病,病原体种类检测中价值.方法 采用上转发光免疫分析仪及配套试剂检测79例细菌感染性疾病患者、59例病毒感染性疾病患者和68例健康体检者血清样本中PCT和IL-6含量,应用受试者工作特征（ROC）曲线进行分析.结果 细菌感染组PCT和IL-6含量高于病毒感染组及正常对照组,差异具有统计学意义（P＜0.05）,病毒感染组PCT和IL-6含量与正常对照组比较差异不具统计学意义（P＞0.05）;应用ROC曲线分析PCT和IL-6鉴别诊断细菌感染的效能,曲线下面积分别为0.854和0.783,显示PCT效能优于IL-6;对三组的PCT与IL-6水平进行了相关性分析,结果显示,PCT与IL-6在检测细菌感染中成线性相关（r=0.424,P＜0.001）;对两项指标进行单项检测时,PCT的灵敏度和特异性分别是82.3％和79.5％,IL-6的灵敏度和特异性分别是69.6％和68.5％;二者联合检测时灵敏度和特异性是88.6％和67.0％.结论 在病原微生物的感染诊断中,PCT是一个优秀指标,若能与IL-6联合检测,更有利于细菌感染性疾病与病毒感染性疾病的鉴别诊断.     

骨感染患者血清CRP、PCT、IL-6水平与病情发展和预后的关系

目的探讨骨感染患者血清C反应蛋白(CRP)、降钙素原(PCT)、白介素-6(IL-6)水平与病情发展和预后的关系。方法病例源于2018年1月至2019年1月本院骨科收治的88例骨感染患者(作为疾病组)和32无骨感染患者(作为对照组),依据疾病组患者的感染程度分为轻度组(n=30)、中度组(n=35)、重度组(n=23),检测各组血清CRP、PCT、IL-6水平,分析血清CRP、PCT、IL-6水平与骨感染患者病情发展、预后的关系。结果不同病情程度骨感染患者血清CRP、PCT、IL-6水平存在明显的差异,且均较对照组明显升高,表现为重度组>中度组>轻度组>对照组(P<0.05);Logistic回归分析提示CRP、PCT、IL-6水平是骨感染严重程度的影响因素(P<0.05);术后半年随访复发率23.86%,复发者血清CRP、PCT、IL-6水平均明显高于未复发者(P<0.05);且Spearman相关性分析显示骨感染患者复发与术前CRP、PCT、IL-6水平均呈明显的正相关(r=0.791、0.928、0.942,均P<0.001)。结论骨感染患者血清CRP、PCT、IL-6水平与其病情严重、预后复发存在明显的正相关,或可通过监测CRP、PCT、IL-6水平以预测患者病情发展和预后。     

Serum procalcitonin for differentiating bacterial infection from disease flares in patients with autoimmune diseases

Early differentiation between bacterial infections and disease flares in autoimmune disease patients is important due to different treatments. Seventy-nine autoimmune disease patients with symptoms suggestive of infections or disease flares were collected by retrospective chart review. The patients were later classified into two groups, disease flare and infection. C-reactive protein (CRP) and serum procalcitonin (PCT) levels were measured. The CRP and PCT levels were higher in the infection group than the disease flare group (CRP,11.96 mg/dL ± 9.60 vs 6.42 mg/dL ± 7.01, P = 0.003; PCT, 2.44 ng/mL ± 6.55 vs 0.09 ng/mL ± 0.09, P < 0.001). The area under the ROC curve (AUC; 95% confidence interval) for CRP and PCT was 0.70 (0.58-0.82) and 0.84 (0.75-0.93), which showed a significant difference (P < 0.05). The predicted AUC for the CRP and PCT levels combined was 0.83, which was not significantly different compared to the PCT level alone (P = 0.80). The best cut-off value for CRP was 7.18 mg/dL, with a sensitivity of 71.9% and a specificity of 68.1%. The best cut-off value for PCT was 0.09 ng/mL, with a sensitivity of 81.3% and a specificity of 78.7%. The PCT level had better sensitivity and specificity compared to the CRP level in distinguishing between bacterial infections and disease flares in autoimmune disease patients. The CRP level has no additive value when combined with the PCT level when differentiating bacterial infections from disease flares.