Sera of patients with systemic lupus erythematosus cross-neutralizes dengue viruses

Dengue hemorrhagic fever with bleeding and fluid overload in a patient with active lupus nephritis: a case report of diagnostic and therapeutic challenges

BACKGROUND

Diagnosis and management of dengue hemorrhagic fever (DHF) can be challenging in the presence of confounding comorbidities. Important confounders are conditions that alter hematological parameters and intra/extra vascular fluid distribution. We report the case of a patient with active lupus nephritis, who developed DHF with subsequent bleeding and fluid overload. This is the first case report to highlight a unique set of diagnostic and therapeutic challenges in DHF in this context.

CASE PRESENTATION

A seventeen-year-old girl with lupus nephritis class IV developed a renal flare of lupus and subsequently developed DHF with bleeding per vaginum. Due to acute kidney injury, she was managed with a restrictive fluid approach during the ascending limb with blood transfusion when required, and close monitoring for hemodynamic instability. During the descending limb, hourly input was transiently increased due to a rise in hematocrit. This precipitated nephrogenic pulmonary edema, which was managed with mechanical ventilation and continuous renal replacement therapy.

CONCLUSIONS

This patient posed two diagnostic challenges: diagnosis of dengue in a patient with lupus-related bicytopenia, and diagnosis of dengue leakage in a patient with nephrotic syndrome-related ascites. There were three therapeutic difficulties: deciding the fluid quota for DHF in the presence of renal impairment, and balancing the risks and benefits of steroids and anticoagulation in lupus nephritis with dengue. As decisions in such instances are patient-specific, sharing of individual experiences will help guide management decisions.

Immunoglobulin M seroneutralization for improved confirmation of Japanese encephalitis virus infection in a flavivirus-endemic area

BACKGROUND

The mainstay of diagnostic confirmation of acute Japanese encephalitis (JE) involves detection of anti-JE virus (JEV) immunoglobulin M (IgM) by enzyme-linked immunosorbent assay (ELISA). Limitations in the specificity of this test are increasingly apparent with the introduction of JEV vaccinations and the endemicity of other cross-reactive flaviviruses. Virus neutralization testing (VNT) is considered the gold standard, but it is challenging to implement and interpret. We performed a pilot study to assess IgG depletion prior to VNT for detection of anti-JEV IgM neutralizing antibodies (IgM-VNT) as compared with standard VNT.

METHODS

We evaluated IgM-VNT in paired sera from anti-JEV IgM ELISA-positive patients (JE n=35) and negative controls of healthy flavivirus-naïve (n=10) as well as confirmed dengue (n=12) and Zika virus (n=4) patient sera. IgM-VNT was subsequently performed on single sera from additional JE patients (n=76).

RESULTS

Anti-JEV IgG was detectable in admission serum of 58% of JE patients. The positive, negative and overall percentage agreement of IgM-VNT as compared with standard VNT was 100%. A total of 12/14 (86%) patient samples were unclassified by VNT and, with sufficient sample available for IgG depletion and IgG ELISA confirming depletion, were classified by IgM-VNT. IgM-VNT enabled JE case classification in 72/76 (95%) patients for whom only a single sample was available.

CONCLUSIONS

The novel approach has been readily adapted for high-throughput testing of single patient samples and it holds promise for incorporation into algorithms for use in reference centres.

Viral Infections and Systemic Lupus Erythematosus: New Players in an Old Story

A causal link between viral infections and autoimmunity has been studied for a long time and the role of some viruses in the induction or exacerbation of systemic lupus erythematosus (SLE) in genetically predisposed patients has been proved. The strength of the association between different viral agents and SLE is variable. Epstein-Barr virus (EBV), parvovirus B19 (B19V), and human endogenous retroviruses (HERVs) are involved in SLE pathogenesis, whereas other viruses such as Cytomegalovirus (CMV) probably play a less prominent role. However, the mechanisms of viral-host interactions and the impact of viruses on disease course have yet to be elucidated. In addition to classical mechanisms of viral-triggered autoimmunity, such as molecular mimicry and epitope spreading, there has been a growing appreciation of the role of direct activation of innate response by viral nucleic acids and epigenetic modulation of interferon-related immune response. The latter is especially important for HERVs, which may represent the molecular link between environmental triggers and critical immune genes. Virus-specific proteins modulating interaction with the host immune system have been characterized especially for Epstein-Barr virus and explain immune evasion, persistent infection and self-reactive B-cell "immortalization". Knowledge has also been expanding on key viral proteins of B19-V and CMV and their possible association with specific phenotypes such as antiphospholipid syndrome. This progress may pave the way to new therapeutic perspectives, including the use of known or new antiviral drugs, postviral immune response modulation and innate immunity inhibition. We herein describe the state-of-the-art knowledge on the role of viral infections in SLE, with a focus on their mechanisms of action and potential therapeutic targets.