Unusual non-infectious cause of meningitis

Meningitis, though commonly caused by various infectious agents, may also have non-infectious aetiologies. The clinical presentation, however may be identical to infectious meningitis. We present a case of a female in her 50s who presented with fever, headache, vomiting and neck rigidity. She had features of inflammatory polyarthritis, cold sensitivity, puffy digits, alopecia and easy fatigability. No evidence of infection was found, and serological features consistent with mixed connective tissue disease (MCTD) were revealed, which led to the diagnosis of MCTD-related aseptic meningitis.

Association of anti-NR2 and U1RNP antibodies with neurotoxic inflammatory mediators in cerebrospinal fluid from patients with neuropsychiatric systemic lupus erythematosus

BACKGROUND

Autoantibodies (auto Abs) and inflammatory mediators (IMs) in cerebrospinal fluid (CSF) may be involved in the pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE). It is suggested that anti-N-methyl D-aspartate receptor NR2 subunit (NR2) Ab can develop NP manifestation after blood-brain barrier (BBB) abruption. We also reported the association between NPSLE and CSF anti-U1RNP Ab. In the present study, combined effects of CSF anti-NR2 and anti-U1RNP Abs on IMs in patients with NPSLE were examined.

METHODS

CSF samples were collected from 69 patients with NPSLE and 13 non-NPSLE controls. CSF anti-NR2 and anti-U1RNP Abs were determined using ELISA. Levels of IL-6, IL-8, and monokine induced by IFN-γ (MIG) in CSF were measured by quantitative multiplex cytokine analysis.

RESULTS

CSF IL-6 levels were higher in CSF anti-NR2-positive than in CSF anti-NR2-negative patients (p = 0.003) and non-NPSLE controls (p = 0.015) and were positively correlated with anti-NR2 titer (r = 0.42). CSF IL-8 levels were higher in CSF anti-U1RNP-positive than in CSF anti-U1RNP-negative patients (p = 0.041). CSF MIG levels were more elevated in CSF anti-NR2-positive (p = 0.043) and anti-U1RNP-positive patients (p = 0.029) than in non-NPSLE controls. Additionally, in double positive (DP; both anti-NR2 and U1RNP Ab positive) group, CSF IL-6 and MIG levels were significantly higher than in the double negative (DN; both anti-NR2 and U1RNP Ab negative) group. However, combined effect of both Abs on IM elevation and clinical manifestation was not clear.

CONCLUSIONS

CSF anti-NR2 and anti-U1RNP Abs have different effects on the elevation of CSF IM levels in patients with NPSLE. Additional effect of anti-U1RNP Abs on anti-NR2 Ab-mediated NP manifestation, however, was not recognized in our study.

Recent Advances in Research Regarding Autoantibodies in Connective Tissue Diseases and Related Disorders

Connective tissue diseases (CTDs), also known as systemic autoimmune diseases, involve a variety of autoantibodies against cellular components. An important factor regarding these autoantibodies is that each antibody is exclusively related to a certain clinical feature of the disease type, which may prove useful in clinical practice. Thus far, more than 100 types of autoantibodies have been found in CTDs, and most of their target antigens have been identified. Many of these autoantigens are enzymes or regulators involved in important cellular functions, such as gene replication, transcription, repair/recombination, RNA processing, and protein synthesis, as well as proteins that form complexes with RNA and DNA. This article reviews the autoantibodies for each CTD, along with an assessment of their clinical significance, and provides suggestions regarding their utilization for clinical practice.

Organ-specific biomarkers in lupus

Systemic lupus erythematosus (SLE) is a complex and highly heterogeneous disease, which affects multiple organs, including joints, skin, kidneys, heart, hematopoietic system, and nerve system. While the etiopathogenesis of SLE still remains unclear, genetic susceptibilities and aberrant epigenetic modifications are believed to be involved. For precision therapy, it is necessary to assess accurately and objectively organ involvements and disease activity, which is difficult by current clinical laboratory tests. Biomarkers, which are a biologic, genetic, epigenetic or a chemical characteristic and conveniently detectable, serve as measures of disease diagnosis, activity, prognosis, and manifestation prediction, thereby providing instruction for individualized therapy. In addition, biomarkers differ according to different manifestations, since the disease activity index and treatments vary significantly. For example, unlike other non-renal SLE, lupus nephritis requires significant immunosuppressive drugs. Over the past decades, the research on biomarkers in lupus has been strengthened and numerous promising biomarkers have been identified at levels of genomics, transcriptomics and proteomics. In this review, we summarize the conventional and novel biomarkers in the tissue-specific manner, and discuss their roles in specific organ diagnosis, future manifestation prediction, disease activity assessment and their correlation with histology results. By doing so, it aims to shed a light on individualized treatment.

Modulation of Neuroinflammation in the Central Nervous System: Role of Chemokines and Sphingolipids

Neuroinflammation is a process involved in the pathogenesis of different disorders, both autoimmune, such as neuropsychiatric systemic lupus erythematosus, and degenerative, such as Alzheimer's and Parkinson's disease. In the central nervous system, the local milieu is tightly regulated by different mediators, among which are chemoattractant cytokines, also known as chemokines. These small molecules are able to modulate trafficking of immune cells in the course of nervous system development or in response to tissue damage, and different patterns of chemokine molecule and receptor expression have been described in several neuroinflammatory disorders. In recent years, a number of studies have highlighted a pivotal role of sphingolipids in regulating neuroinflammation. Sphingolipids have different functions, among which are the control of leukocyte egress from lymphonodes into inflamed tissues, the expression of various mediators of inflammation and a direct effect on the cells of the central nervous system as regulators of neuroinflammation. In the future, a better knowledge of these two groups of mediators could provide insight into the pathogenesis of neuroinflammatory disorders and could help develop novel diagnostic tools and therapeutic strategies.

Direct and indirect pathogenic roles of autoantibodies in systemic autoimmune diseases

Autoantibody (autoAb) production in patients with systemic autoimmune diseases is a hallmark of disease entity, activity and prognosis. Although a large number of autoAbs have been discovered to date, there is a limited number of autoAbs whose pathogenic roles have been clearly determined. However, intriguing evidence has recently been provided of possible pathogenic roles for anti-neutrophil cytoplasmic Abs (ANCAs) against myeloperoxidase (MPO) in ANCA-associated vasculitides (AAV) and for anti-citrullinated protein Abs (ACPAs) in rheumatoid arthritis (RA). Of note, these autoAbs are thought to display both direct and indirect effects on organ failure. Additionally, some autoAbs have been reported to play pathogenic roles in brain damage in patients with neuropsychiatric systemic lupus erythematosus (NPSLE), which is one of the most refractory autoimmune disorders. Thus the binding of autoAbs to a certain sequence of the N-methyl-D-aspartate receptor subunit NR2 (anti-NR2 Abs) may directly induce hippocampal neuronal injury. On the other hand, anti-U1 ribonucleoprotein (RNP) Abs might be pathogenic by inducing neurotoxic inflammatory mediators intrathecally. Such autoAb measurements are also clinically meaningful for treatment selection.

Brain MRI in patients with diffuse psychiatric/neuropsychological syndromes in systemic lupus erythematosus

BACKGROUND

Manifestations in neuropsychiatric systemic lupus erythematosus (NPSLE), especially active diffuse NPSLE syndromes, are some of the most difficult complications of the disease. For the evaluation and the diagnosis of central nervous system manifestations, including NPSLE, MRI is a very useful tool to detect the various abnormalities. However, the relationship between brain MRI findings and clinical variables has not yet been clarified in patients with diffuse NPSLE.

OBJECTIVES

The aim of this study is to investigate the pathogenesis of diffuse NPSLE, by comparing various parameters such as serum autoantibodies and cytokines in cerebrospinal fluid (CSF) with abnormal findings revealed on brain MRIs in patients with diffuse NPSLE.

METHODS

Fifty-three patients with diffuse NPSLE admitted to our University Hospital from 1992 to 2012 were exhaustively enrolled in this study. Their medical charts and brain MRI scans were reviewed. The relationship of MRI abnormalities with various parameters was analysed.

RESULTS

As many as 25 of 53 patients (47.2%) had abnormal MRI findings. MRI findings improved after treatment in 10 of 17 patients for whom follow-up studies were available. MRI abnormalities were not correlated with age at the onset of diffuse NPSLE. However, the disease duration of SLE was significantly longer in patients with abnormal MRI findings (p=0.0009). MRI abnormalities were not significantly associated with serum autoantibodies. However, there were significant elevations of the CSF protein level (p=0.0106) and the CSF interleukin 6 level (p=0.0225) in patients with abnormal MRI findings. Patients with MRI abnormalities showed significantly higher overall mortality (p=0.0348).

CONCLUSIONS

The results revealed that MRI abnormalities in diffuse NPSLE might be heterogeneous with regard to their reversibility. These data also indicate that patients with diffuse NPSLE and MRI abnormalities have more severe inflammation in the central nervous system related to the activity of diffuse NPSLE, as evidenced by poorer prognosis.

Neuropsychiatric systemic lupus erythematosus and cognitive dysfunction: the MRL-lpr mouse strain as a model

Mouse models of autoimmunity, such as (NZB×NZW)F1, MRL/MpJ-Fas(lpr) (MRL-lpr) and BXSB mice, spontaneously develop systemic lupus erythematosus (SLE)-like syndromes with heterogeneity and complexity that characterize human SLE. Despite their inherent limitations, such models have highly contributed to our current understanding of the pathogenesis of SLE as they provide powerful tools to approach the human disease at the genetic, cellular, molecular and environmental levels. They also allow novel treatment strategies to be evaluated in a complex integrated system, a favorable context knowing that very few murine models that adequately mimic human autoimmune diseases exist. As we move forward with more efficient medications to treat lupus patients, certain forms of the disease that requires to be better understood at the mechanistic level emerge. This is the case of neuropsychiatric (NP) events that affect 50-60% at SLE onset or within the first year after SLE diagnosis. Intense research performed at deciphering NP features in lupus mouse models has been undertaken. It is central to develop the first lead molecules aimed at specifically treating NPSLE. Here we discuss how mouse models, and most particularly MRL-lpr female mice, can be used for studying the pathogenesis of NPSLE in an animal setting, what are the NP symptoms that develop, and how they compare with human SLE, and, with a critical view, what are the neurobehavioral tests that are pertinent for evaluating the degree of altered functions and the progresses resulting from potentially active therapeutics.