Intravenous immunoglobulins in the treatment of dengue illness

Severe dengue in the intensive care unit

Dengue fever is considered the most prolific vector-borne disease in the world, with its transmission rate increasing more than eight times in the last two decades. While most cases present mild to moderate symptoms, 5% of patients can develop severe disease. Although the mechanisms are yet not fully comprehended, immune-mediated activation leading to excessive cytokine expression is suggested as a cause of the two main findings in critical patients: increased vascular permeability that may shock and thrombocytopenia, and coagulopathy that can induce hemorrhage. The risk factors of severe disease include previous infection by a different serotype, specific genotypes associated with more efficient replication, certain genetic polymorphisms, and comorbidities such as diabetes, obesity, and cardiovascular disease. The World Health Organization recommends careful monitoring and prompt hospitalization of patients with warning signs or propensity for severe disease to reduce mortality. This review aims to update the diagnosis and management of patients with severe dengue in the intensive care unit.

Hyperimmune Globulins for the Management of Infectious Diseases

This review is focused on the use of hyperimmune globulin therapy to treat some infectious diseases of viral or bacterial origin. Despite the introduction of antibiotics and vaccines, plasma immunoglobulin therapy from whole blood donation can still play a key role. These treatments provide passive transfer of high-titer antibodies that either reduces the risk or the severity of the infection and offer immediate but short-term protection against specific diseases. Antibody preparations derived from immunized human donors are commonly used for the prophylaxis and treatment of rabies, hepatitis A and B viruses, varicella-zoster virus, and pneumonia caused by respiratory syncytial virus, Clostridium tetani, Clostridium botulinum. The use of hyperimmune globulin therapy is a promising challenge, especially for the treatment of emerging viral infections for which there are no specific therapies or licensed vaccines.

Rescue therapy with intravenous immunoglobulin in severe refractory dengue: A pilot study

Background

Severe dengue causes more than 22,000 deaths annually worldwide. Complicated dengue has high mortality of 44-72%. Disordered immune system with capillary leak and thrombocytopenia are hallmark of complicated dengue. Intravenous immunoglobulin (IV Ig) therapy has shown to be effective in complicated dengue in pediatric age group with refractory shock, but studies in adults are lacking. Its immunoresuscitative role is not yet fully explored in critically ill patients with severe dengue.

Methods

This is retrospective observational study of patients with complicated dengue fever who were administered IV Ig therapy in a tertiary care hospital of southern India from 01 Jan 2018 to 31 Dec 2019.

Results

A total of 999 patients with dengue were admitted; 754 (75.47%) were males, and 245 (24.53%) were females. A total of 402 (40.24%) patients presented with warning signs. Bleeding was seen in 121 patients (12.11%); 102 (10.21%) had shock; 29 (2.90%) had acute kidney injury and 24 (2.40%) had adult respiratory distress syndrome. Overall, four people died (mortality rate: 0.40%). IV Ig in the dose of 0.4 g/kg for 5 days was used in 13 critically ill patients where standard therapy failed, 9 patients with refractory shock (which included three with myocarditis with refractory shock), 2 with encephalitis, 2 in hemophagocytic lymphohistiocytosis. Two patients died, one with myocarditis with refractory shock and another with refractory shock.

Conclusion

IV Ig therapy in critically ill patients with complicated dengue can be used as a rescue therapy.

Carica papaya extract in dengue: a systematic review and meta-analysis

Background

Carica papaya (CP) extract is becoming popular as an unlicensed herbal remedy purported to hasten recovery in dengue infection, mostly based on observations that it may increase platelet counts. This systematic review and meta-analysis aims to critically analyze the evidence from controlled clinical trials on the efficacy and safety of CP extract in the treatment of dengue infection.

Methods

PubMed, LILACS and Google Scholar were searched for randomized or non-randomized trials enrolling patients with suspected or confirmed dengue where CP extract was compared, as a treatment measure, against standard treatment. Recovery of platelet counts as well as other clinical indicators of favourable outcome (duration of hospital stay, prevention of plasma leakage, life threatening complications, and mortality) were assessed.

Results

Nine studies (India-6, Pakistan-1, Indonesia-1, Malaysia-1) met the inclusion criteria. Seven studies showed an increase in platelet counts in patients receiving CP extract, while one study showed no significant difference between the two groups, and direct comparison was not possible in the remaining study. Serious adverse events were not reported. CP extract may reduce the duration of hospital stay (mean difference − 1.98 days, 95% confidence interval − 1.83 to − 2.12, 3 studies, 580 participants, low quality evidence), and cause improvement in mean platelet counts between the first and fifth day of treatment (mean difference 35.45, 95% confidence interval 23.74 to 47.15, 3 studies, 129 participants, low quality evidence). No evidence was available regarding other clinical outcomes.

Conclusions

The clinical value of improvement in platelet count or early discharge is unclear in the absence of more robust indicators of favourable clinical outcome. Current evidence is insufficient to comment on the role of CP extract in dengue. There is a need for further well designed clinical trials examining the effect of CP on platelet counts, plasma leakage, other serious manifestations of dengue, and mortality, with clearly defined outcome measures.

Intravenous immunoglobulin therapy for dengue capillary leak syndrome in a renal allograft recipient

A 45-year-old man presented 4 months after ABOi renal transplantation with febrile illness and bicytopenia necessitating cessation of mycophenolate mofetil. Dengue non-structural protein 1 antigen (NS1 Ag) test was positive. Lowest total leucocyte count was 3.1×10⁹/L and platelet count was 14×10⁹/L. As fever subsided, patient became tachypneic with abdominal distention and hypotension. Ultrasonographic evaluation revealed ascites, gall bladder wall oedema and bilateral pleural effusion consistent with dengue capillary leak syndrome. He developed massive ascites with abrupt weight gain of 4 kg within 24 hours and worsening renal dysfunction. Patient was deteriorating rapidly in spite of adequate supportive care and we gave a trial of intravenous immunoglobulin (0.5 g/kg/day) for 5 days. Patient improved from day 2, and by day 3, he became haemodynamically stable and recovered completely. Patient was stable at discharge and is on regular follow-up.

Dengue virus and antiplatelet autoantibodies synergistically induce haemorrhage through Nlrp3-inflammasome and FcγRIII

Dengue haemorrhagic fever (DHF) typically occurs during secondary infections with dengue viruses (DENVs). Although it is generally accepted that antibody-dependent enhancement is the primary reason why patients with secondary infection are at an increased risk of developing DHF, a growing body of evidence shows that other mechanisms, such as the elicitation of antiplatelet autoantibodies by DENV nonstructural protein NS1, also play crucial roles in the pathogenesis of DHF. In this study, we developed a "two-hit" model of secondary DENV infection to examine the respective roles of DENV (first hit) and antiplatelet Igs (second hit) on the induction of haemorrhage. Mice were first exposed to DENV and then exposed to antiplatelet or anti-NS1 Igs 24 hours later. The two-hit treatment induced substantial haemorrhage, coagulopathy, and cytokine surge, and additional treatment with antagonists of TNF-α, IL-1, caspase-1, and FcγRIII ameliorated such effects. In addition, knockout mice lacking the Fcγ receptor III, Toll-like receptor 3, and inflammasome components Nlrp3 and caspase-1 exhibited considerably fewer pathological alterations than did wild type controls. These findings may provide new perspectives for developing feasible approaches to treat patients with DHF.

Corticosteroids in the treatment of dengue shock syndrome

Dengue infection causes significant morbidity and mortality in over 100 countries worldwide, and its incidence is on the rise. The pathophysiological basis for the development of severe dengue, characterized by plasma leakage and the “shock syndrome” are poorly understood. No specific treatment or vaccine is available, and careful monitoring and judicious administration of fluids forms the mainstay of management at present. It is postulated that vascular endothelial dysfunction, induced by cytokine and chemical mediators, is an important mechanism of plasma leakage. Although corticosteroids are potent modulators of the immune system, their role in pharmacological doses in modulating the purported immunological effects that take place in severe dengue has been a subject of controversy. The key evidence related to the role of corticosteroids for various manifestations of dengue are reviewed here. In summary, there is currently no high-quality evidence supporting the beneficial effects of corticosteroids for treatment of shock, prevention of serious complications, or increasing platelet counts. Non-randomized trials of corticosteroids given as rescue medication for severe shock have shown possible benefit. Nonetheless, the evidence base is small, and good-quality trials are lacking. We reiterate the need for well-designed and adequately powered randomized controlled trials of corticosteroids for the treatment of dengue shock.

Dengue: Moving from Current Standard of Care to State-of-the-Art Treatment

Treatment of dengue remains supportive in the absence of targeted antiviral therapy or approved vaccines. Responsive fluid management is key to preventing progression to shock or other severe manifestations. The dynamic natural history of dengue infection and its influence on hemodynamic homeostasis needs to be carefully considered in the planning of individualized therapy. Though largely self-limiting, the sheer burden of dengue disease on the global population will result in atypical manifestations especially in children, older adults, and comorbid patients. Management of these has not yet been systematized. The failure of recent randomized controlled trials to show utility for antiviral and immunomodulatory agents in dengue is disappointing. Vaccine candidates hold promise, but growing outbreaks require more robust, evidence-based management guidelines to inform clinicians, especially in novel epidemic situations.

May early intervention with high dose intravenous immunoglobulin pose a potentially successful treatment for severe cases of tick-borne encephalitis?

Background

Arthropod-borne viral encephalitis of diverse origins shows similar clinical symptoms, histopathology and magnetic resonance imaging, indicating that the patho mechanisms may be similar. There is no specific therapy to date. However, vaccination remains the best prophylaxis against a selected few. Regardless of these shortcomings, there are an increasing number of case reports that successfully treat arboviral encephalitis with high doses of intravenous immunoglobulins.

Discussion

To our knowledge, high dose intravenous immunoglobulin has not been tested systematically for treating severe cases of tick-borne encephalitis. Antibody-dependent enhancement has been suspected, but not proven, in several juvenile cases of tick-borne encephalitis. Although antibody-dependent enhancement during secondary infection with dengue virus has been documented, no adverse effects were noticed in a controlled study of high dose intravenous immunoglobulin therapy for dengue-associated thrombocytopenia. The inflammation-dampening therapeutic effects of generic high dose intravenous immunoglobulins may override the antibody-dependent enhancement effects that are potentially induced by cross-reactive antibodies or by virus-specific antibodies at sub-neutralizing levels.

Summary

Analogous to the increasing number of case reports on the successful treatment of other arboviral encephalitides with high dose intravenous immunoglobulins, we postulate whether it may be possible to also treat severe cases of tick-borne encephalitis with high dose intravenous immunoglobulins as early in the course of the disease as possible.

Treatment of dengue fever

The endemic area for dengue fever extends over 60 countries, and approximately 2.5 billion people are at risk of infection. The incidence of dengue has multiplied many times over the last five decades at an alarming rate. In the endemic areas, waves of infection occur in epidemics, with thousands of individuals affected, creating a huge burden on the limited resources of a country's health care system. While the illness passes off as a simple febrile episode in many, a few have a severe illness marked by hypovolemic shock and bleeding. Iatrogenic fluid overload in the management may further complicate the picture. In this severe form dengue can be fatal. Tackling the burden of dengue is impeded by several issues, including a lack of understanding about the exact pathophysiology of the infection, inability to successfully control the vector population, lack of specific therapy against the virus, and the technical difficulties in developing a vaccine. This review provides an overview on the epidemiology, natural history, management strategies, and future directions for research on dengue, including the potential for development of a vaccine.

Dengue shock

Shock syndrome is a dangerous complication of dengue infection and is associated with high mortality. Severe dengue occurs as a result of secondary infection with a different virus serotype. Increased vascular permeability, together with myocardial dysfunction and dehydration, contribute to the development of shock, with resultant multiorgan failure. The onset of shock in dengue can be dramatic, and its progression relentless. The pathogenesis of shock in dengue is complex. It is known that endothelial dysfunction induced by cytokines and chemical mediators occurs. Diagnosis is largely clinical and is supported by serology and identification of viral material in blood. No specific methods are available to predict outcome and progression. Careful fluid management and supportive therapy is the mainstay of management. Corticosteroids and intravenous immunoglobulins are of no proven benefit. No specific therapy has been shown to be effective in improving survival.

Dengue hemorrhagic fever and shock syndromes

OBJECTIVES

To provide a comprehensive review of dengue, with an emphasis on clinical syndromes, classification, diagnosis, and management, and to outline relevant aspects of epidemiology, immunopathogenesis, and prevention strategies. Dengue, a leading cause of childhood mortality in Asia and South America, is the most rapidly spreading and important arboviral disease in the world and has a geographic distribution of > 100 countries.

DATA SOURCE

Boolean searches were carried out by using PubMed from 1975 to March 2009 and the Cochrane Database of Systematic Reviews from 1993 to March 2009 to identify potentially relevant articles by key search terms such as: "dengue"; "dengue fever"; "dengue hemorrhagic fever"; "dengue shock syndrome"; "severe dengue" and "immunopathogenesis," pathogenesis," "classification," "complications," and "management." In addition, authoritative seminal and up-to-date reviews by experts were used.

STUDY SELECTION

Original research and up-to-date reviews and authoritative reviews consensus statements relevant to diagnosis and therapy were selected.

DATA EXTRACTION AND SYNTHESIS

We considered the most relevant articles that would be important and of interest to the critical care practitioner as well as authoritative consensus statements from the World Health Organization and the Centers for Disease Control and Prevention. Dengue viral infections are caused by one of four single-stranded ribonucleic acid viruses of the family Flaviviridae and are transmitted by their mosquito vector, Aedes aegypti. The clinical syndromes caused by dengue viral infections occur along a continuum; most cases are asymptomatic and few present with severe forms characterized by shock. Management is predominantly supportive and includes methods to judiciously resolve shock and control bleeding while at the same time preventing fluid overload.

CONCLUSIONS

Dengue is no longer confined to the tropics and is a global disease. Treatment is supportive. Outcomes can be optimized by early recognition and cautious titrated fluid replacement, especially in resource-limited environments.

Small molecule drug discovery for Dengue and West Nile viruses: applying experience from hepatitis C virus

There are currently no specific treatments for infection with Dengue virus (DENV) and West Nile Virus (WNV). Drug-discovery programs are underway for both viruses, but as yet no small molecules have advanced to clinical trials. Hepatitis C virus (HCV) is a related flavivirus that has been the focus of intense drug discovery efforts for the last two decades. Many approaches currently being pursued for DENV and WNV have been previously attempted for HCV with varying degrees of success. The experience with HCV may direct DENV and WNV efforts towards approaches with the best chance of success. Based on experience with HCV, the viral polymerase and protease are attractive targets to focus on since these have been most successful to date. Cell-based phenotypic screening may also yield attractive inhibitors. The helicase and methyltransferase enzymes are likely to prove difficult targets and host target approaches are fraught with safety concerns.