Increased pro-inflammatory cytokines (TNF-alpha and IL-6) and anti-inflammatory compounds (sTNFRp55 and sTNFRp75) in Brazilian patients during exanthematic dengue fever.

Pro-inflammatory cytokines, tumor necrosis factor (TNF-alpha), interleukin-6 (IL-6) and interleukin-1beta (IL-1beta) as well as anti-inflammatory compounds, soluble TNF-Receptor p55 (sTNFRp55), sTNFRp75 and IL-1 receptor antagonist (sIL-1Ra), were investigated in 34 Brazilian cases of dengue fever (DF) originated from a study of exanthematic virosis. The presence of pro-inflammatory cytokines was detected in sera from these patients by ELISA. TNF-alpha and IL-6 levels were significantly higher than control subjects in 32% and 52% patients, respectively. To our knowledge this was the first time a receptor antagonist and soluble receptors for cytokines were detected in sera obtained during exanthematic DF without hemorrhagic manifestations. Both sTNFRp55 and sTNFRp75 were consistently elevated in 42% and 84% patients, respectively. Most patients had IL-1beta levels not different from those of normal subjects, except for one case. Only 16% patients had altered levels of IL-1Ra. Previous studies in dengue hemorrhagic fever patients demonstrated production of these soluble factors; here we observed that they are found in absence of hemorrhagic manifestations. The possible role of these anti-inflammatory compounds in immune cell activation and in regulating cytokine-mediated pathogenesis during dengue infection is discussed.     

Relationship of thrombopoietin and interleukin-11 levels to thrombocytopenia associated with dengue disease

Thrombocytopenia is one of the main clinical findings of dengue. In this work we examined the levels of thrombopoietin (TPO) and interleukin-11 (IL-11), two of the most potent regulators of platelet production, in serum from 28 patients with dengue fever (DF). Patients with DF had increased levels of TPO, compared with healthy individuals (p<0.005). Patients with dengue hemorrhagic fever (DHF, n=7), the more severe form of dengue, had higher TPO levels than patients with DF (p<0.001). Serum TPO levels and platelet counts were inversely correlated in both DF and DHF patients. IL-11 was detectable in neither DF nor DHF patients. Our results demonstrate that thrombocytopenia in dengue disease is associated with changes in the serum levels of TPO, but not IL-11, suggesting that this cytokine could be a potential early clinical marker of the severity of dengue disease.     

Role of interleukin-12 in patients with dengue hemorrhagic fever

Interleukin (IL)-12 has a broad range of activities including regulation of cytokine synthesis and selective promotion of Th1-type cell development. A shift from a Th1-type response to Th2-type has been suggested to be important in the pathogenesis of dengue hemorrhagic fever (DHF). This study was undertaken to investigate the possible role of IL-12 in this shift. A total of 76 patients with various grades of dengue illness and 21 normal healthy controls were tested for IL-12 levels in serum samples and IL-12 mRNA in their peripheral blood mononuclear cells. The results showed that the levels of IL-12 were the highest in patients with dengue fever (270+/-102 pg ml(-1)) followed by decreasing levels in the patients with DHF grade I (198+/-86 pg ml(-1); P<0.05) and DHF grade II (84+/-52 pg ml(-1); P<0.001). Neither IL-12 nor its mRNA could be detected in the patients with DHF grades III and IV. The cytokine appeared and reached peak levels during the first 4 days of illness, started to decline by day 5-8 and disappeared by day 9 onwards. The absence of IL-12 during severe illness and late phases of the disease may be responsible for the shift to a Th2-type response and thus for the pathogenesis of DHF.     

A retrospective serological study of Japanese who contracted dengue fever in Thailand

Between September and November 1981, some members of a survey team from Japan suffered from a febrile illness diagnosed clinically as dengue fever during their stay in a village in Khon-Kaen Province, in the north-eastern part of Thailand. The morbidity rate in the team was as high as 69% (11/16). Blood samples were taken from 12 of the 16 members of the team in February, 1982 in Japan and the serum specimens were examined for antibodies to dengue (DEN), Japanese encephalitis (JE) and yellow fever (YF) viruses respectively. The results of the tests indicated that all 8 members who had had symptoms had been infected with DEN type 1 virus. No case of inapparent infection with dengue viruses was found. Of these 8 persons, seven had had neutralizing (N) antibody to JE virus before infection, but their clinical manifestations had been similar to those of an individual without N antibody to JE virus and were typical symptoms of dengue fever, such as leukopenia and "saddle-back" fever, without hemorrhagic manifestations, as seen from platelet counts and hematocrit values.     

Role of cognitive parameters in dengue hemorrhagic fever and dengue shock syndrome

Dengue is becoming recognized as one of the most important vector-borne human diseases. It is predominant in tropical and subtropical zones but its geographical distribution is progressively expanding, making it an escalating global health problem of today. Dengue presents with spectrum of clinical manifestations, ranging from asymptomatic, undifferentiated mild fever, dengue fever (DF), to dengue hemorrhagic fever (DHF) with or without shock (DSS), a life-threatening illness characterized by plasma leakage due to increased vascular permeability. Currently, there are no antiviral modalities or vaccines available to treat and prevent dengue. Supportive care with close monitoring is the standard clinical practice. The mechanisms leading to DHF/DSS remains poorly understood. Multiple factors have been attributed to the pathological mechanism, but only a couple of these hypotheses are popular in scientific circles. The current discussion focuses on underappreciated factors, temperature, natural IgM, and endotoxin, which may be critical components playing roles in dengue pathogenesis.     

Elevated levels of soluble ST2 protein in dengue virus infected patients

Levels of the soluble form of the interleukin-1 receptor-like 1 protein (IL-1RL-1/ST2) are elevated in the serum of patients with diseases characterized by an inflammatory response. The objective of this study was to determine the concentration of soluble ST2 (sST2) in dengue infected patients during the course of the disease. Twenty-four patients with confirmed dengue infection, classified as dengue fever, and 11 patients with other febrile illness (OFI) were evaluated. Levels of sST2 in serum and laboratory variables usually altered during dengue infections were measured. Dengue infected patients had higher serum sST2 levels than OFI at the end of the febrile stage and at defervescence (p=0.0088 and p=0.0004, respectively). Patients with secondary dengue infections had higher serum sST2 levels compared with patients with primary dengue infections (p=0.047 at last day of fever and p=0.030 at defervescence). Furthermore, in dengue infected patients, we found a significant negative correlation of sST2 with platelet and WBC counts, and positive correlation with thrombin time and transaminases activity. We suggest that sST2 could be a potential marker of dengue infection, could be associated with severity or could play a role in the immune response in secondary dengue virus infection.     

Correlation of serum tumor necrosis factor-alpha,interleukin-4 and soluble interleukin-2 receptor levels with radiologic and clinical manifestations in active pulmonary tuberculosis

The precise clinical manifestations of tuberculosis are likely to result from a complex interaction between the host and the pathogen. We took serum samples from a group of patients with a variety of clinical and radiological stages of pulmonary tuberculosis in order to characterize tumor necrosis factor-alpha (TNF-alpha), interleukin-4 (IL-4) and soluble interleukin-2 receptor (sIL-2R) response. We further evaluated whether the levels of TNF-alpha, IL-4 and soluble IL-2R are related with each other, and also evaluated the levels of TNF-alpha, IL-4 and sIL-2R after anti-tuberculosis therapy and relation with radiologic scores. Forty-three inpatients with active pulmonary tuberculosis and 19 healthy controls participated in the study. Patients were divided into four categories radiologically on chest X-ray (minimal, moderate-advanced, far-advanced and with miliary infiltration). Concentrations of TNF-alpha (20.9+/-10/15.4+/-8 pg/ml) and sIL-2R (2569+/-842/1444+/-514 pg/ml) were statistically different between patients and controls (p=0.02 and p=0.0001, respectively). Before chemotherapy there was a positive correlation between TNF-alpha and sIL-2R (r=0.34), but there was no correlation between IL-4 and TNF-alpha, and between IL-4 and sIL-2R (r=-0.23 and r=-0.22). The TNF-alpha level was not statistically different in four groups before and after chemotherapy. Results of this study provided some evidence confirming the previously reported role of TNF-alpha, IL-4 and sIL 2R in the control of tuberculosis, but these cytokines were not found related with disease severity.     

An in vitro model for dengue virus infection that exhibits human monocyte infection, multiple cytokine production and dexamethasone immunomodulation

An important cytokine role in dengue fever pathogenesis has been described. These molecules can be associated with haemorrhagic manifestations, coagulation disorders, hypotension and shock, all symptoms implicated in vascular permeability and disease worsening conditions. Several immunological diseases have been treated by cytokine modulation and dexamethasone is utilized clinically to treat pathologies with inflammatory and autoimmune etiologies. We established an in vitro model with human monocytes infected by dengue virus-2 for evaluating immunomodulatory and antiviral activities of potential pharmaceutical products. Flow cytometry analysis demonstrated significant dengue antigen detection in target cells two days after infection. TNF-alpha, IFN-alpha, IL-6 and IL-10 are produced by in vitro infected monocytes and are significantly detected in cell culture supernatants by multiplex microbead immunoassay. Dexamethasone action was tested for the first time for its modulation in dengue infection, presenting optimistic results in both decreasing cell infection rates and inhibiting TNF-alpha, IFN-alpha and IL-10 production. This model is proposed for novel drug trials yet to be applied for dengue fever.     

Elevated levels of interleukin-13 and IL-18 in patients with dengue hemorrhagic fever

Interleukin (IL)-13 is produced by T helper 2 (Th2)-type cells and inhibits the production of proinflammatory cytokines by activated monocytes, while IL-18 is a pleiotropic cytokine that induces interferon-gamma and plays an important role in the development of Th1-type cells. Role of the shift from a Th1-type response to Th2-type has been suggested in the pathogenesis of dengue hemorrhagic fever (DHF). This study was undertaken to investigate the possible protective/pathogenic role of IL-13 and IL-18 in patients with DHF. Sera were collected from a total of 84 patients with various grades of dengue illness and 21 normal healthy controls and tested for IL-13 and IL-18 levels using commercial enzyme-linked immunosorbent assay kits. The results showed that very low levels of IL-13 (4+/-3 pg ml(-1)) and IL-18 (15+/-4 pg ml(-1)) were detected in the sera of healthy controls. In dengue patients, the levels of IL-13 and IL-18 were the highest in the patients with DHF grade IV (205+/-103 pg ml(-1) and 366+/-155 pg ml(-1), respectively) and the lowest in patients with dengue fever (22+/-12 pg ml(-1) and 76+/-50 pg ml(-1), respectively). Both the cytokines appeared (IL-13=20+/-11 pg ml(-1) and IL-18=70+/-45 pg ml(-1)) during the first 4 days of illness and reached peak levels (IL-13=204+/-96 pg ml(-1) and IL-18=360+/-148 pg ml(-1)) by day 9 onwards. The presence of high levels of IL-13 and IL-18 during severe illness and late phases of the disease suggests that both of these cytokines may contribute to the shift from a Th1- to Th2-type response and thus to the pathogenesis of DHF.     

An emerging role for the anti-inflammatory cytokine interleukin-10 in dengue virus infection

Infection with dengue virus (DENV) causes both mild dengue fever and severe dengue diseases, such as dengue hemorrhagic fever and dengue shock syndrome. The pathogenic mechanisms for DENV are complicated, involving viral cytotoxicity, immunopathogenesis, autoimmunity, and underlying host diseases. Viral load correlates with disease severity, while the antibody-dependent enhancement of infection largely determines the secondary effects of DENV infection. Epidemiological and experimental studies have revealed an association between the plasma levels of interleukin (IL)-10, which is the master anti-inflammatory cytokine, and disease severity in patients with DENV infection. Based on current knowledge of IL-10-mediated immune regulation during infection, researchers speculate an emerging role for IL-10 in clinical disease prognosis and dengue pathogenesis. However, the regulation of dengue pathogenesis has not been fully elucidated. This review article discusses the regulation and implications of IL-10 in DENV infection. For future strategies against DENV infection, manipulating IL-10 may be an effective antiviral treatment in addition to the development of a safe dengue vaccine.     

Economic burden of dengue fever in China: A retrospective research study

BackgroundDengue fever has been a significant public health challenge in China. This will be particularly important in the context of global warming, frequent international travels, and urbanization with increasing city size and population movement. In order to design relevant prevention and control strategies and allocate health resources reasonably, this study evaluated the economic burden of dengue fever in China in 2019.MethodsThe economic burden of dengue fever patients was calculated from both family and the organisation perspectives. A survey was conducted among 1,027 dengue fever patients in Zhejiang, Chongqing, and Yunnan Provinces. Treatment expenses, lost working days, and insurance reimbursement expenses information were collected to estimate the total economic burden of dengue fever patients in 2019. The expenditures related to dengue fever prevention and control from government, Center for Disease Control and Prevention (CDC), communities and subdistrict offices of 30 counties (or districts) in Zhejiang Province and Chongqing City were also collected.ResultsThe direct, indirect and total economic burden for dengue fever patients in 2019 in the three Provinces were about 36,927,380.00 Chinese Yuan (CNY), 10,579,572.00 CNY and 46,805,064.00 CNY, respectively. The costs for prevention and control of dengue fever for the counties (or districts) without cases, counties (or districts) with imported cases, and counties (or districts) with local cases are 205,800.00 CNY, 731,180.00 CNY and 6,934,378.00 CNY, respectively. The total investment of dengue fever prevention and control in the 30 counties in China in 2019 was approximately 3,166,660,240.00 CNY.ConclusionThe economic burden of dengue fever patients is relatively high, and medical insurance coverage should be increased to lighten patients’ direct medical economic burden. At the same time, the results suggests that China should increase funding for primary health service institutions to prevent dengue fever transmission.     

Cytotoxic factor-autoantibodies: possible role in the pathogenesis of dengue haemorrhagic fever

During dengue virus infection a unique cytokine, cytotoxic factor (hCF), is produced that is pathogenesis-related and plays a key role in the development of dengue haemorrhagic fever (DHF). However, what regulates the adverse effects of hCF is not known. We have previously shown that anti-hCF antibodies raised in mice, neutralise the pathogenic effects of hCF. In this study we have investigated the presence and levels of hCF-autoantibodies in sera of patients with various severity of dengue illness (n=136) and normal healthy controls (n=50). The highest levels of hCF-autoantibodies (mean+/-S.D.=36+/-20 U ml(-1)) were seen in patients with mild illness, the dengue fever (DF), and 48 out of 50 (96%) of the sera were positive. On the other hand the hCF-autoantibody levels declined sharply with the development of DHF and the levels were lowest in patients with DHF grade IV (mean+/-S.D.=5+/-2 U ml(-1); P=<0.001 as compared to DF). Only one of the 13 DHF grade IV patients had an antibody level above the 'cut-off' value (mean plus 3 S.D. of the control sera). The analysis of data with respect to different days of illness further showed that the highest levels of hCF-autoantibodies were present in DF patients at >9 days of illness. Moreover, the DF patients at all time points, i.e. 1-4, 5-8 and >9 days of illness had significantly higher levels of hCF-autoantibodies (P<0.001) than patients with DHF grade I, II, III and IV. In addition DHF grade I and grade II patients had significantly more positive specimens than DHF grade III and grade IV patients at all time points. These results suggest that elevated levels of hCF-autoantibodies protect the patients against the development of severe forms of DHF and, therefore, it may be useful as a prognostic indicator.     

Activated peripheral lymphocytes with increased expression of cell adhesion molecules and cytotoxic markers are associated with dengue fever disease

The immune mechanisms involved in dengue fever and dengue hemorrhagic/dengue shock syndrome are not well understood. The ex vivo activation status of immune cells during the dengue disease in patients was examined. CD4 and CD8 T cells were reduced during the acute phase. Interestingly, CD8 T cells co-expressing activation marker HLA-DR, Q, P, and cytolytic granule protein-Tia-1 were significantly higher in dengue patients than in controls. Detection of adhesion molecules indicated that in dengue patients the majority of T cells (CD4 and CD8) express the activation/memory phenotype, characterized as CD44HIGH and lack the expression of the na?ve cell marker, CD62L LOW. Also, the levels of T cells co-expressing ICAM-1 (CD54), VLA-4, and LFA-1 (CD11a) were significantly increased. CD8 T lymphocytes expressed predominantly low levels of anti-apoptotic molecule Bcl-2 in the acute phase, possibly leading to the exhibition of a phenotype of activated/effector cells. Circulating levels of IL-18, TGF-b1 and sICAM-1 were significantly elevated in dengue patients. Early activation events occur during acute dengue infection which might contribute to viral clearance. Differences in expression of adhesion molecules among CD4 and CD8 T cells might underlie the selective extravasation of these subsets from blood circulation into lymphoid organs and/or tissues. In addition, activated CD8 T cells would be more susceptible to apoptosis as shown by the alteration in Bcl-2 expression. Cytokines such as IL-18, TGF-b1, and sICAM-1 may be contributing by either stimulating or suppressing the adaptative immune response, during dengue infection, thereby perhaps establishing a relationship with disease severity.     

Cytokine cascade in dengue hemorrhagic fever: implications for pathogenesis

Dengue virus produces a mild acute febrile illness, dengue fever (DF) and a severe illness, dengue hemorrhagic fever (DHF). The characteristic feature of DHF is increased capillary permeability leading to extensive plasma leakage in serous cavities resulting in shock. The pathogenesis of DHF is not fully understood. This paper presents a cascade of cytokines, that in our view, may lead to DHF. The main feature is the early generation of a unique cytokine, human cytotoxic factor (hCF) that initiates a series of events leading to a shift from Th1-type response in mild illness to a Th2-type response resulting in severe DHF. The shift from Th1 to Th2 is regulated by the relative levels of interferon-gamma and interleukin (IL)-10 and between IL-12 and transforming growth factor-beta, which showed an inverse relationship in patients with DF.     

Elevated levels of plasma VEGF in patients with dengue hemorrhagic fever

Vascular endothelial growth factor (VEGF) can be produced by monocytes and endothelial cells. It plays important role in angiogenesis and vascular permeability. The phenomenon of extensive plasma leakage into various serous cavities of the body is a cardinal symptom of dengue hemorrhagic fever (DHF). This study was performed to investigate the role of VEGF in patients with DHF. Plasma samples collected from the 53 dengue fever (DF) patients (including 14 patients with DHF), and 5 additional subjects with non-dengue febrile illness as controls were tested for VEGF levels using commercial enzyme-linked immunosorbent assay (ELISA) kits. The results showed that median plasma levels of VEGF in the patients with DHF (54.6 pg ml(-1)) were significantly higher than those of DF (14.6 pg ml(-1)) and control group (27.1 pg ml(-1)) (P<0.05). In addition, VEGF levels in DF patients were not significantly different from those of control patients with non-dengue febrile illness (P=0.17). Multiple regression analysis was used to analyze the clinical variables independently associated with VEGF levels. The data showed that D-dimer levels were significantly associated with VEGF levels. In this study, plasma VEGF levels in patients with DHF were significantly higher than values from DF patients. The association between increased plasma VEGF levels and increased plasma D-dimer levels in the patients with dengue illness suggests that activation of the fibrinolytic system may play a role in VEGF production in the patients with DF.     

Systemic host inflammatory and coagulation response in the Dengue virus primo-infection

BACKGROUND: Dengue virus infection has been rising in tropical countries. Clinical manifestations range from fever and general malaise to hemorrhagic manifestations and death. The role of endothelial damage and cytokines has not been well established for dengue infection. OBJECTIVE: Determine the profile of the pro-inflammatory cytokines and several markers of coagulopathy of dengue infection. METHODS: Patients admitted between September 2000 and April 2001, who met the WHO dengue diagnosis criteria, were enrolled. Blood samples were collected at 0, 6, 12, 24, 48, 72 h and 5 and 7 days after hospitalization. Profile of pro-inflammatory cytokines, markers of coagulopathy, protein C, protein S, d-dimer, prothrombin time, activated partial thromboplastin time, fibrinogen and activated protein C levels were determined. RESULTS: Thirty-three patients were enrolled. Median (range) age was 31 (13-70) years; 51.5% (17/33) were female. Ten of 33 (30%) presented with hemorrhagic manifestations. Patients were classified: Grade 1: 23/33 (70%), Grade II: 10/33 (30%). At study entry IL-6 was the most elevated, followed by IL-8 and TNF alpha. IL-10 was not elevated. No significant differences (P < 0.05) were demonstrated in the levels of any of the haemostatic or cytokine markers by disease severity (Grade I versus Grade II patients). CONCLUSION: The systemic host inflammatory and coagulation activation response occurs early in patients with dengue viral infection in the absence of severe hemorrhagic manifestations, and provides the basis for considering future clinical study in the use of recombinant human activated protein C to treat patients with severe sepsis from dengue infection.     

Monitoring of clinical and laboratory data in two cases of imported Lassa fever

During 2000, four cases of fatal Lassa fever were imported from Africa to Europe. In two patients, consecutive serum samples were available for monitoring of virus load and cytokine levels in addition to standard laboratory data. Both patients had non-specific early clinical symptoms including high fever. Patient 1 developed multi-organ failure and died of hemorrhagic shock on day 15 of illness, while patient 2 died of respiratory failure due to aspiration without hemorrhage on day 16. Ribavirin was administered to both patients beginning only on day 11. High serum aspartate aminotransferase and lactate dehydrogenase (LDH) levels were remarkable in both patients. Patient 1 had an initial virus load of 10(6) S RNA copies/ml as measured by real-time RT-PCR. Viremia increased steadily and reached a plateau of approximately 10(8)-10(9) copies/ml 4 days before death, while IFN-gamma and TNF-alpha rose to extremely high levels only shortly before death. In contrast, in patient 2 the virus load decreased from 10(7) to 10(6) copies/ml during the late stage of illness which was paralleled by a decrease in the IFN-gamma and TNF-alpha levels. The IL-10 level increased when specific IgM and IgG appeared. These data suggest that a high virus load and high levels of pro-inflammatory cytokines in the late stage of Lassa fever play an important role in the pathogenesis of hemorrhage, multi-organ failure, and shock in Lassa fever.     

Severe dengue is associated with consumption of von Willebrand factor and its cleaving enzyme ADAMTS-13

Background

Thrombocytopenia, bleeding and plasma leakage are cardinal features of severe dengue. Endothelial cell activation with exocytosis of Weibel-Palade bodies (WPBs) may play an etiological role in this condition.

Methods and Principal Findings

In a cohort of 73 Indonesian children with dengue hemorrhagic fever (DHF), of which 30 with dengue shock syndrome (DSS), we measured plasma levels of the WPB constituents von Willebrand factor antigen (VWF:Ag), VWF propeptide and osteoprotegerin (OPG), together with activity levels of the VWF-cleaving enzyme ADAMTS-13 and the amount of VWF in a platelet binding conformation (VWF activation factor). Compared with healthy controls (n = 17), children with DHF/DSS had significantly higher levels of VWF:Ag, VWF propeptide and OPG and decreased ADAMTS-13 activity. The VWF activation factor was also significantly higher in DHF/DSS and highest in children who died. There were significant differences in the kinetics of the various WPB constituents: VWF propeptide and OPG levels decreased toward discharge, while VWF:Ag levels were lower than expected at enrollment with plasma levels increasing toward discharge. Moreover, VWF propeptide levels correlated better with markers of disease severity (platelet count, liver enzymes, serum albumin and pleural effusion index) than corresponding VWF levels. Together, these findings suggest that there is consumption of VWF in DHF/DSS. In 4 out of 15 selected children with low ADAMTS-13 levels on admission, we found a remarkable reduction in the large and intermediate VWF multimers in the discharge blood samples, consistent with an acquired von Willebrand disease.

Conclusion

These findings suggest that severe dengue is associated with exocytosis of WPBs with increased circulating levels of VWF:Ag, VWF propeptide and OPG. High circulating levels of VWF in its active conformation, together with low ADAMTS-13 activity levels, are likely to contribute to the thrombocytopenia and complications of dengue. During the convalescence phase, qualitative defects in VWF with loss of larger VWF multimers may develop.