Association of dengue hemorrhagic fever with the HLA system

The frequency of HLA antigens was determined in 82 unrelated patients who had been hospitalized with the most severe form of dengue hemorrhagic fever: shock, dehydration and severe hemorrhages (DHF/DSS). The HLA-A1, HLA-B plank, HLA Cw1 and HLA-A29 antigens showed a significant difference when their values were compared with the normal control group.     

Association of HLA-DRB114, -DRB116 and -DQB105 with MuSK-myasthenia gravis in patients from Turkey

Susceptibility to myasthenia gravis (MG) has been demonstrated with several HLA in different disease subgroups. HLA-DR14, -DR16 and -DQ5 were reported as predisposing factors in muscle-specific kinase antibody positive MG (MuSK-MG). These markers were evaluated in MG subgroups from Turkey. Among 164 generalized MG patients, 116 had antibodies against anti-acetylcholine receptor (AChR-MG) and 48 had MuSK-MG. Only HLA-DRB1 and DQB1 allele groups reported to be associated with MuSK-MG were compared with 250 healthy controls (HC). Highly significant associations of both DRB1^∗16 and DRB1^∗14 were found with MuSK-MG compared to HC (p = 1.9 × 10⁻⁵, OR: 4.95 and p = 0.0028, OR: 3.1). On the contrary, HLA-DRB1^∗03 was less frequent in MuSK-MG (p = 0.006, OR: 0.09). DQB1^∗05 was also associated with MuSK-MG (p = 2.5 × 10⁻⁶ OR: 4.8). This study provides a replication of the highly significant associations of both HLA-DRB1^∗16,-DRB1^∗14 and -DQB1^∗05 with MuSK-MG. Moreover, HLA-DRB1^∗03 appears to have a distinguishing role for this disease subgroup compared to early-onset and AChR-MG.     

Antibody responses to an immunodominant nonstructural 1 synthetic peptide in patients with dengue fever and dengue hemorrhagic fever

Two flaviviruses, dengue (DEN) virus and Japanese encephalitis (JE) virus, are important because of their global distribution and the frequency of epidemics in tropical and subtropical areas. To study the B-cell epitopes of nonstructural 1 (NS1) glycoprotein and anti-NS1 antibody response in DEN infection, a series of 15-mer synthetic peptides from the predicted B-cell linear epitopes of DEN-2 NS1 protein were prepared. Enzyme-linked immunosorbent assay (ELISA) was performed to analyze antibody responses to these peptides from sera of both DEN and JE patients. One peptide derived from DEN-2 NS1, D2 NS1-P1 (amino acids 1–15), was identified as the immunodominant epitope that reacted with sera from dengue fever (DF) patients but not JE patients. The isotype of D2 NS1-P1-specific antibodies was mainly immunoglobulin M (IgM) in all sera that tested positive. A specificity study demonstrated that sera from all four DEN types reacted with D2 NS1-P1. A dynamics study showed that specific antibodies to this peptide could be detected as early as 2 days after the onset of symptoms. We observed significant anti-D2 NS1-P1 antibody responses in 45% of patients with primary and secondary infections with DF or with dengue hemorrhagic fever. This is the first report demonstrating that significant anti-DEN NS1 antibodies can be induced in the sera of patients with primary DEN infection. J. Med. Virol. 57:1–8, 1999. © 1999 Wiley-Liss, Inc.     

Natural killer cells in dengue hemorrhagic fever/dengue shock syndrome

Natural killer (NK) cell activity against K-562 target cells and HNK-1+ cell levels were serially determined in peripheral blood of 62 Thai children with dengue hemorrhagic fever/dengue shock syndrome aged 4-12 years and 59 age-matched normal controls. The studies were performed on febrile stage, 1st and 2nd day of subsidence of fever (shock stage), 3rd and 4th day of subsidence of fever (early convalescent stage) and once again on the late convalescent stage (approximately 14-18 days after subsidence of fever). The study revealed that during the course of disease the NK cell activity was not changed significantly from the normal controls. In contrast, the levels of HNK-1+ cells, which exhibited almost all NK and killer cell functional activities, were significantly decreased in the febrile and the shock stages and were normal in the early and late convalescent stages. The NK cell activity, on the per-cell basis, was significantly increased in the early disease stage when compared to that of the later period of the disease and of the normal controls. The study also revealed that patients with grade III of disease severity exhibited significantly more NK cell functional activities per cell than grade II on febrile stage and the first day of shock. These results suggest that natural killer cells were active in defense against dengue viral infection and might play some role in the pathogenesis of dengue hemorrhagic fever/dengue shock syndrome. Their functions might also determine the severity of the disease.     

HLA-DRB1 as a risk or resistance factor in Autoimmune Hepatitis

Although the pathogenesis of Autoimmune Hepatitis (AIH) is unknown, the susceptibility is determined in part by genes linked to the region of HLA class II. The study included 47 unrelated individuals with the diagnostic of type 1 AIH. A control group (n = 81) of healthy individuals was included. The alleles were tested for HLA class II genotyping using polymerase chain reaction and sequence-specific primers technique (PCR-SSP). Among patients with AIH alleles occurring at higher frequencies were DRB1*04, DRB1*03, DRB1*01, DRB1*07 and DRB1*13. With reference to controls the following alleles were the most prevalent DRB1*07, DRB1*11, DRB1*08, DRB1*13 and DRB1*01. In comparison with the control group, AIH patients revealed a greater occurrence of the DRB1*03 and DRB1*04. These alleles can be considered as predisposing factors for the development of AIH. By contrast, DRB1*08 and DRB1*11 alleles were less frequent among patients and hence could be involved in disease resistance.     

The pathology of dengue hemorrhagic fever

An estimated 2.5 billion people are at risk of dengue infection, and of the 100 million cases of dengue fever per year, up to 500,000 develop dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS), the life-threatening forms of the infection. The large majority of DHF/DSS occurs as the result of a secondary infection with a different serotype of the virus. While not completely understood, there is evidence that the target cells include dendritic reticulum cells, monocytes, lymphocytes, hepatocytes, and vascular endothelial cells. Viral replication appears to occur in dendritic cells, monocytes, and possibly circulating lymphoid cells, and damage to these and other target cells occurs through immune-mediated mechanisms related to cross-reacting antibodies and cytokines released by dendritic cells, monocytes, and vascular endothelium. There is evidence of a concomitant cellular activation as well as immune suppression during the infection. The activation of memory T cells results in cascades of inflammatory cytokines, including tumor necrosis factor-alpha, interleukins (IL-2, IL-6, and IL-8), and other chemical mediators that increase vascular endothelial permeability or trigger death of target cells through apoptosis. Pathological studies in humans are uncommon, and a suitable animal model of DHF/DSS does not exist. The current treatment of DHF/DSS is symptomatic, and prevention is through vector control. As such, there is a great impetus for the development of vaccines and novel therapeutic molecules to impede viral replication in infected cells or counteract the effects of specific inflammatory mediators on target cells. The role of genetics in relation to resistance to DHF/DSS also requires clarification.     

Co-circulations of two genotypes of dengue virus in 2006 out-break of dengue hemorrhagic fever in Karachi, Pakistan.

BACKGROUND: The status of dengue genotypes involved in the recent epidemic out-breaks in Pakistan is not well defined. OBJECTIVES: We sought to analyze the predominant genotype responsible for the most severe and largest out-break of dengue hemorrhagic fever (DHF) that hit Karachi in 2006. STUDY DESIGN: Retrospective analysis of stored serum samples for dengue virus genotype by multiplex RT-PCR, anti-dengue IgM, IgG and review of clinical charts of patients admitted to Aga Khan University Hospital. RESULTS: Viral RNA detection of 250 patients revealed positive results in 185 (74.0%) samples. DEN-2 was predominant genotype (n=104, 56.2%) Dengue specific antibodies were detected in 139 samples of which 81 were classified as primary cases. DEN-2 accounted for these. Within secondary cases, 63.2% were due to DEN-2 (total 57), the rest were positive for DEN-3. DHF (p=0.064) and abdominal pain (p=0.059) were more frequently associated with DEN-2 as compared to DEN-3. None of the samples were positive for DEN-1 or DEN-4. CONCLUSION: Co-circulation of DEN-2 and DEN-3 was responsible for the 2006 out-break in Karachi. Primary and secondary cases were seen in both groups. Cases with DHF showed marginal association with DEN-2. Introduction of a new serotype (DEN-3) and or a genotypic shift of endemic serotype (DEN-2) are the probable factors for the recent out-break of DHF in this region.     

Acute pancreatitis in dengue hemorrhagic fever

We reported a case of acute pancreatitis as the complication of dengue hemorrhagic fever (DHF). This complication can cause more severe fatal condition, and difficulties in treatment, although it is rare. Dengue hemorrhagic fever (DHF) is one of the endemic diseases and often come as an outbreak event in South East Asia including Indonesia. Dengue hemorrhagic fever (DHF) is a global public health problem, because until now there has been no medicine to eradicate the dengue virus, no dengue vaccine and difficult to eradicate the mosquitoes as the contagious vector. Diagnosis and treatment of acute pancreatitis as early as possible is important to improve the patient's condition and survival. The patient was a 59 year old male and had been treated conservatively. The patient was admitted to the hospital, oral fasting until the fourth day, given parenteral nutrition, antibiotic and other intravenous medicines. Initial oral liquid diet was given on the fifth day of hospitalization and changed gradually according to the condition. The patient was then improved and discharged from the hospital.     

Phenotypic and genotypic characterization of dengue virus isolates differentiates dengue fever and dengue hemorrhagic fever from dengue shock syndrome

Dengue viruses (DENV) cause 50-100 million cases of acute febrile disease every year, including 500,000 reported cases of dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Viral factors have been proposed to influence the severity of the disease, but markers of virulence have never been identified on DENV. Three DENV serotype-1 isolates from the 2007 epidemic in Cambodia that are derived from patients experiencing the various clinical forms of dengue were characterized both phenotypically and genetically. Phenotypic characteristics in vitro, based on replication kinetics in different cell lines and apoptosis response, grouped isolates from DF and DHF patients together, whereas the virus isolate from a DSS patient showed unique features: a lower level of replication in mammalian cells and extensive apoptosis in mosquito cells. Genomic comparison of viruses revealed six unique amino acid residues in the membrane, envelope, and in non-structural genes in the virus isolated from the DSS patient.     

Idiopathic purpura fulminans in dengue hemorrhagic fever

Purpura fulminans is a rapidly progressive thrombotic disease that has been described during both severe bacterial and viral infections. Disseminated intravascular coagulation (DIC), antiphospholipid antibodies and acquired or congenital C and S protein deficiency are thought to play a role in its pathogenesis. Here we report the case of a 4-year-old girl who developed gangrene of all her fingers and toes following dengue shock syndrome complicated by DIC and also discuss its management.     

Cross-reactive T-cell responses to the nonstructural regions of dengue viruses among dengue fever and dengue hemorrhagic fever patients in Malaysia

Dengue virus infections are a major cause of morbidity and mortality in tropical and subtropical areas in the world. Attempts to develop effective vaccines have been hampered by the lack of understanding of the pathogenesis of the disease and the absence of suitable experimental models for dengue viral infection. The magnitude of T-cell responses has been reported to correlate with dengue disease severity. Sixty Malaysian adults with dengue viral infections were investigated for their dengue virus-specific T-cell responses to 32 peptides antigens from the structural and nonstructural regions from a dengue virus isolate. Seventeen different peptides from the C, E, NS2B, NS3, NS4A, NS4B, and NS5 regions were found to evoke significant responses in a gamma interferon enzyme-linked immunospot (ELISPOT) assay of samples from 13 selected patients with dengue fever (DF) and dengue hemorrhagic fever (DHF). NS3 and predominantly NS3(422-431) were found to be important T-cell targets. The highest peaks of T-cell responses observed were in responses to NS3(422-431) and NS5(563-571) in DHF patients. We also found almost a sevenfold increase in T-cell response in three DHF patients compared to three DF patient responses to peptide NS3(422-431). A large number of patients' T cells also responded to the NS2B(97-106) region. The ELISPOT analyses also revealed high frequencies of T cells that recognize both serotype-specific and cross-reactive dengue virus antigens in patients with DHF.     

Serum cytokine/chemokine profiles in patients with dengue fever (DF) and dengue hemorrhagic fever (FHD) by using protein array

BackgroundDENV infection can induce different clinical manifestations varying from mild forms to dengue fever (DF) or the severe hemorrhagic fever (DHF). Several factors are involved in the progression from DF to DHF. No marker is available to predict this progression. Such biomarker could allow a suitable medical care at the beginning of the infection, improving patient prognosis.ObjectivesThe aim of this study was to compare the serum expression levels of acute phase proteins in a well-established cohort of dengue fever (DF) and dengue hemorrhagic fever (DHF) patients, in order to individuate a prognostic marker of diseases severity.Study designThe serum levels of 36 cytokines, chemokines and acute phase proteins were determined in DF and DHF patients and compared to healthy volunteers using a multiplex protein array and near-infrared (NIR) fluorescence detection. Serum levels of IL-1ra, IL-23, MIF, sCD40 ligand, IP-10 and GRO-α were also determined by ELISA.ResultsAt the early stages of infection, GRO-α and IP-10 expression levels were different in DF compared to DHF patients. Besides, GRO-α was positively correlated with platelet counts and IP-10 was negatively correlated with total protein levels.ConclusionsThese findings suggest that high levels of GRO-α during acute DENV infection may be associated with a good prognosis, while high levels of IP-10 may be a warning sign of infection severity.     

Retinoids,race and the pathogenesis of dengue hemorrhagic fever

Dengue hemorrhagic fever (DHF) is the most significant mosquito-borne viral disease worldwide in terms of illness, mortality and economic cost, but the pathogenesis of DHF is not well understood and there is no specific treatment or vaccine. Based on evidence of liver involvement, it is proposed that dengue virus and retinoids interact to cause cholestatic liver damage, resulting in the spillage of stored retinoids into the circulation and in an endogenous form of hypervitaminosisis A manifested by the signs and symptoms of the disease, including: fever, severe joint and bone pain, capillary leakage, thrombocytopenia, headache, and gastrointestinal symptoms. While retinoids in low concentration are essential for numerous biological functions, they are prooxidant, cytotoxic, mutagenic and teratogenic in higher concentration, especially when unbound to protein, and an endogenous form of vitamin A intoxication is recognized in cholestasis. The model tentatively explains the observations that 1) repeat infections are more severe than initial dengue virus infections; 2) the incidence of denue has increased dramatically worldwide in recent decades; 3) DHF is less prevalent in people of African ancestry than those of other racial backgrounds; and 4) infants are protected from dengue. The retinoid toxicity hypothesis of DHF predicts the co-existence of low serum concentrations of retinol coupled with high concentrations of retinoic acid and an increased percentage of retinyl esters to total vitamin A. Subject to such tests, it may be possible to treat DHF effectively using drugs that target the metabolism and expression of retinoids.     

Retinoids,race and the pathogenesis of dengue hemorrhagic fever

Dengue hemorrhagic fever (DHF) is the most significant mosquito-borne viral disease worldwide in terms of illness, mortality and economic cost, but the pathogenesis of DHF is not well understood and there is no specific treatment or vaccine. Based on evidence of liver involvement, it is proposed that dengue virus and retinoids interact to cause cholestatic liver damage, resulting in the spillage of stored retinoids into the circulation and in an endogenous form of hypervitaminosisis A manifested by the signs and symptoms of the disease, including: fever, severe joint and bone pain, capillary leakage, thrombocytopenia, headache, and gastrointestinal symptoms. While retinoids in low concentration are essential for numerous biological functions, they are prooxidant, cytotoxic, mutagenic and teratogenic in higher concentration, especially when unbound to protein, and an endogenous form of vitamin A intoxication is recognized in cholestasis. The model tentatively explains the observations that 1) repeat infections are more severe than initial dengue virus infections; 2) the incidence of denue has increased dramatically worldwide in recent decades; 3) DHF is less prevalent in people of African ancestry than those of other racial backgrounds; and 4) infants are protected from dengue. The retinoid toxicity hypothesis of DHF predicts the co-existence of low serum concentrations of retinol coupled with high concentrations of retinoic acid and an increased percentage of retinyl esters to total vitamin A. Subject to such tests, it may be possible to treat DHF effectively using drugs that target the metabolism and expression of retinoids.     

Elevated levels of IL-8 in dengue hemorrhagic fever

Dengue virus causes dengue fever, a mild febrile illness, and at times dengue hemorrhagic fever (DHF), a severe illness the pathogenesis of which is not fully understood. Given the crucial roles played by interleukin-8 (IL-8) as a chemoattractant cytokine and in inflammatory processes, levels of circulating IL-8 in the sera and IL-8 mRNA in the peripheral blood mononuclear cells (PBMC) were measured in 99 patients of a recent dengue epidemic that occurred in India in 1996 and in 21 normal healthy controls. Twenty-six of the patients had dengue fever (DF) and the remaining 73 were diagnosed as having different grades of DHF. All the control normal sera were negative for IL-8, so were their PBMC for IL-8 mRNA. Increased levels of IL-8 in the sera and IL-8 mRNA in their PBMC were observed in patients with severe illness of DHF grades III and IV. Only two out of 26 patients of DF and one out of 10 DHF grade I patient were positive for IL-8 and all three deteriorated to DHF grade IV within 24 hr. All six patients of DHF grade IV who died had higher serum level of IL-8 above 200 pg/ml, the highest being 5,568 pg/ml in one patient; the presence of mRNA for IL-8 was very high in all patients. A striking correlation was observed between increased levels of IL-8 and severe DHF, with greater levels in patients with increased grade of the disease and death. These results suggest that IL-8 may have an important role and may be an indicator of increasing severity of the disease and death. J. Med. Virol. 56:280–285, 1998. © 1998 Wiley-Liss, Inc.     

Impaired fibrinolysis in the pathogenesis of dengue hemorrhagic fever

The mechanisms contributing to bleeding complications in dengue hemorrhagic fever were studied by investigating the pattern of activation of the coagulation and fibrinolytic systems in 50 children with severe dengue hemorrhagic fever. Thirteen patients (26%) died, and activation of coagulation was most pronounced in the deceased group. Fibrinolysis was also activated, but this activation was relatively weak compared with that of coagulation as a result of persistently high plasminogen activator inhibitor levels. Plasminogen activator inhibitor also prevented a switch from the procoagulant to the profibrinolytic state in lethal dengue hemorrhagic fever, which was further enhanced by an acquired protein C deficiency. The present study is the first to demonstrate such a mechanism in a viral infection. This imbalance between coagulation and fibrinolysis may be used as a prognostic marker, but it may also be a target for future therapeutic intervention.     

Association of MCP-1 promotor polymorphism with disease severity of Crimean-Congo hemorrhagic fever

Crimean-Congo hemorrhagic fever (CCHF) is a thick-borne viral zoonotic disease. The pathogenesis and the reasons why cases have a mild or severe course in CCHF have not yet been explained. In this study, we investigated the relationship between promoter -2518 A/G single-nucleotide polymorphism (SNP) of the MCP-1 gene and the clinical course of CCHF. The MCP-1-2518 A/G SNP (rs1024611) frequency was examined in 128 virologically/serologically confirmed CCHF patients and 181 healthy controls by using the PCR-RFLP method. When CCHF patients and controls were compared, no significant difference was found between genotype distributions and allele frequencies of the -2518 A/G SNP of MCP-1 gene (P > .05). Compared to the AA genotype, both AG (P = .016; OR = 2.57) and GG genotype (P = .039; OR = 3.43) were found with significantly higher frequencies in mild/moderate cases than in severe cases. Compared to the AG + GG genotype, AA showed a significant risk for severe CCHF (60.0% vs 38.4%, P = .02; OR = 2.41). In contrast, the AG genotype showed a significant protective effect against severe disease compared to AA + GG genotype (29.1% vs 47.9%, P = .013; OR = 2.58). Compared to mild/moderate cases, the A allele was found to be significantly higher in severe cases (0.745 vs 0.623, P = .039; OR = 1.77). However, no significant relationship was found between fatal and nonfatal cases in terms of genotype or allele frequencies (P > .05). In conclusion, both -2518 AA genotype and A allele of MCP-1 were associated with disease severity, and the AG genotype had a protective effect against a severe disease course in CCHF patients.