Serum and cerebrospinal fluid cytokine concentrations in subacute sclerosing panencephalitis

CSF Interleukins-12, 17 and Interferon-γ Levels in Children with Subacute Sclerosing Panencephalitis

Subacute sclerosing panencephalitis (SSPE) is a devastating fatal condition caused by mutated measles virus. It predominantly affects children of younger age and invariably leads to mortality. Though reported rarely, the disease continues to cause significant morbidity in children. The authors conducted an observational study in which CSF was withdrawn from 24 cases of confirmed SSPE (Dyken's criteria) and interleukin levels were estimated by ELISA method. On analysis, IL-12 was significantly elevated in CSF of stage 3 SSPE patients with p value of 0.02. It was elevated in only 2 patients of stage 3 which is the major limitation of this study. No significant difference was seen in IL-17 and interferon-γ levels between different stages of SSPE in serum and CSF. This study highlights the significant elevation of IL-12 cytokine while other studied cytokines (IL-17/ IFN-γ) were not significantly altered in these patients.

Exploring the role of the IL-12/IFN-γ immune axis in subacute sclerosing panencephalitis

BACKGROUND

Subacute sclerosing panencephalitis (SSPE) is a rare but fatal neurological syndrome resulting from persistent measles virus infection in the central nervous system. Despite the availability of a measles vaccine, SSPE continues to pose a significant health burden, and immunogenetic risk factors remain unclear. We aimed to study the role of the interleukin 12 (IL-12)/interferon-gamma (IFN-γ) axis, known for it's significance in antiviral defense, in the development of SSPE.

METHODS

This cross-sectional case-control study recruited consecutive age and sex-matched SSPE cases (n = 51) and controls (n = 51). Gene expressions were quantified for IL-12B, IFNG, IL-12RB1, STAT4, IFNGR1, IFNGR2, STAT1, IRF8, and ISG15 genes using quantitative realtime PCR. Additionally, plasma levels of IL-12p40, IL-12p70, and IFN-γ were measured using the multiplex suspension array platform. Furthermore, single nucleotide polymorphisms (SNPs) in IL-12B, IL-12RB1, IFNG, IFNGR1, IFNGR2, and ISG15 genes were examined using TaqMan SNP genotyping assays. Statistical analyses compared gene expressions, cytokine levels, and alleles and genotypes frequencies between SSPE patients and controls.

RESULTS

Significant alterations in the expression of key IL-12 pathway-related genes were observed in SSPE patients compared to controls, including lower STAT4 (p = 0.0445) and higher IFNGR1 (p = 0.0005) and IRF8 (p = 0.0229). Elevated plasma levels of IL-12p70 (p = 0.0015) and IFN-γ (p = 0.0381) were also observed in SSPE patients. Additionally, associations with SSPE were found for the rs3212227 SNP in IL-12B (p = 0.048), the rs1059293 SNP in IFNGR2 (p = 0.052), and the rs1921 SNP in ISG15 (p = 0.054) genes. Notably, gene-gene interactions among these genes exhibited associations with SSPE.

CONCLUSION

This study provides novel insights into the dysregulation of the IL-12/IFN-γ immune axis in SSPE and underscores the complex interplay between host genetics and viral infection in disease pathogenesis.

Interleukin-2 and its receptors: Implications and therapeutic prospects in immune-mediated disorders of central nervous system

Interleukin-2 (IL-2), the first cloned cytokine, is a multifunctional molecule with diverse cellular origins. As a pivotal T-cell growth factor, IL-2 is crucial for T-cell proliferation and the generation of effector and memory cells. Besides, IL-2 and its receptor (IL-2R) are expressed in various cell types within the brain and have been implicated in the pathogenesis of several neurological disorders. In conditions characterized by primary or secondary inflammatory processes, such as multiple sclerosis, Alzheimer's disease, ischemic stroke, and encephalitis, IL-2/IL-2R expression exhibits region- and subtype-specific and variations associated with disease stages in plasma, cerebrospinal fluid (CSF), and brain tissues. These variations highlight the potential of IL-2/IL-2R as promising diagnostic and prognostic biomarkers, as well as therapeutic targets. This review provides a comprehensive summary of the roles, expression patterns, and regulatory mechanisms of IL-2/IL-2R in immune-mediated disorders of the central nervous system (CNS), with particular emphasis on the impact of genetic polymorphisms in IL-2 and IL-2R subunits on disease susceptibility and progression. In addition, the research advances in IL-2/IL-2R-targeted therapies are also discussed, offering novel insights into the immunotherapeutic strategies for CNS diseases.

Measles Sclerosing Subacute PanEncephalitis (SSPE), an intriguing and ever-present disease: Data, assumptions and new perspectives

BACKGROUND

Subacute sclerosing panencephalitis (SSPE) is a rare, non-treatable and fatal neurological complication of measles, still present due to the return of the epidemic linked to the loosening of vaccination policies. Its mechanism remains unexplained.

OBJECTIVE

The main objective was to investigate explanatory variables relating to the risk of developing SSPE and its pathophysiology.

METHODS

Literature analysis was focused on different varieties of SSPE: perinatal forms, short-incubation forms similar to acute measles inclusion body encephalitis (MIBE), rapidly evolving forms, forms occurring in the immunosuppressed, adult forms, and family forms. In addition, several studies on the parameters of innate immunity and interferon responses of patients were analyzed.

RESULTS

Two main data were highlighted: a relationship between the so-called fulminant forms and the prescription of corticosteroids was established. In familial SSPE, two groups were individualized according to the duration of the latency period, prompting an analysis of patient exomes.

CONCLUSION

Treatment with corticosteroids should be banned. Knowledge of the genes involved and epigenetics should be useful for understanding the pathophysiology of SSPE and other late-onset neurological infections with RNA viruses.

Immune alterations in subacute sclerosing panencephalitis reflect an incompetent response to eliminate the measles virus

In subacute sclerosing panencephalitis (SSPE) the persistence of measles virus (MeV) may be related to the altered immune response. In this study, cytokine responses of lymphocytes and monocytes were evaluated in SSPE compared to controls with non-inflammatory (NICON) and inflammatory (ICON) diseases. Patients with SSPE (n = 120), 78 patients with ICON and 63 patients with NICON were included in this study. Phenotypes of peripheral blood mononuclear cells (PBMC) have been analyzed by flow cytometry. CD3 and CD28, and S. aureus Cowan strain I (SAC) stimulated and unstimulated cells were cultured and IL-2, IL-10, IFN-γ, IL-12p40, IL-12p70 and IL-23 were detected in supernatants by ELISA. MeV peptides were used for MeV-specific stimulation and IFN-γ secretion of PBMC was measured by ELISPOT. Spontaneous and stimulated secretions of IL-10 were lower in SSPE compared to both control groups. T cell stimulation induced lower IFN-γ production than ICON group, but higher IL-2 than NICON group in SSPE. Stimulated PBMC produced lower IL-12p70 in SSPE and had decreased CD46 on the cell surface, suggesting the interaction with the virus. IFN-γ responses against MeV peptides were not prominent and similar to NICON patients. The immune response did not reveal an inflammatory activity to eliminate the virus in SSPE patients. Even IL-10 production was diminished implicating that the response is self-limited in controlling the disease.

IL28B, IL29 and micro-RNA 548 in subacute sclerosing panencephalitis as a rare disease

Subacute sclerosing panencephalitis (SSPE) is a progressive neurodegenerative disease which affects children and young adults, caused by a persistent infection of defective measles virus. IFN-λs (IL-28A, IL-28B and IL-29) are a group of cytokines mediating antiviral responses. It has been shown that IL-29 levels are significantly higher in infected cells with defective measles virus. IL-29 expression is thought to be regulated at post-transcriptional level and miRNA-548 family targets the 3'UTR of the IFNL1 gene. Impaired immune system has an important role as well as viral factors in SSPE. The aim of our study investigates whether IL-28B, IL-29 levels and gene polymorphisms contribute to the damaged immune response leading to the development of SSPE. Also possible association of miR-548 family with IL-29 and SSPE is explored. Frequencies of rs12979860, rs8099917, rs30461, serum levels of IL-28B, IL-29 and expression levels of miR-548b, miR-548c, miR-548i are determined at 64 SSPE patients and 68 healthy controls. Serum IL-29 levels are statistically significant higher in SSPE patients. Allele frequencies of rs8099917 are statistically significant higher in SSPE patients and resulted G allele is found to increase 2.183-fold risk of SSPE. The expression levels of miR-548b-5p, miR-548c-5p and miR-548i are found to be statistically significant higher in SSPE patients. Dramatically increased level of IL-29 seen in patient group indicates that the elevated miR-548 expression is compensatory result of the over-activated immune system response. Further studies referred to IL28, IL29 and related miRNA's will be enlightened the pathogenesis of SSPE.

Advances in Biomarker-Guided Therapy for Pediatric- and Adult-Onset Neuroinflammatory Disorders: Targeting Chemokines/Cytokines

The concept and recognized components of “neuroinflammation” are expanding at the intersection of neurobiology and immunobiology. Chemokines (CKs), no longer merely necessary for immune cell trafficking and positioning, have multiple physiologic, developmental, and modulatory functionalities in the central nervous system (CNS) through neuron–glia interactions and other mechanisms affecting neurotransmission. They issue the “help me” cry of neurons and astrocytes in response to CNS injury, engaging invading lymphoid cells (T cells and B cells) and myeloid cells (dendritic cells, monocytes, and neutrophils) (adaptive immunity), as well as microglia and macrophages (innate immunity), in a cascade of events, some beneficial (reparative), others destructive (excitotoxic). Human cerebrospinal fluid (CSF) studies have been instrumental in revealing soluble immunobiomarkers involved in immune dysregulation, their dichotomous effects, and the cells—often subtype specific—that produce them. CKs/cytokines continue to be attractive targets for the pharmaceutical industry with varying therapeutic success. This review summarizes the developing armamentarium, complexities of not compromising surveillance/physiologic functions, and insights on applicable strategies for neuroinflammatory disorders. The main approach has been using a designer monoclonal antibody to bind directly to the chemo/cytokine. Another approach is soluble receptors to bind the chemo/cytokine molecule (receptor ligand). Recombinant fusion proteins combine a key component of the receptor with IgG1. An additional approach is small molecule antagonists (protein therapeutics, binding proteins, and protein antagonists). CK neutralizing molecules (“neutraligands”) that are not receptor antagonists, high-affinity neuroligands (“decoy molecules”), as well as neutralizing “nanobodies” (single-domain camelid antibody fragment) are being developed. Simultaneous, more precise targeting of more than one cytokine is possible using bispecific agents (fusion antibodies). It is also possible to inhibit part of a signaling cascade to spare protective cytokine effects. “Fusokines” (fusion of two cytokines or a cytokine and CK) allow greater synergistic bioactivity than individual cytokines. Another promising approach is experimental targeting of the NLRP3 inflammasome, amply expressed in the CNS and a key contributor to neuroinflammation. Serendipitous discovery is not to be discounted. Filling in knowledge gaps between pediatric- and adult-onset neuroinflammation by systematic collection of CSF data on CKs/cytokines in temporal and clinical contexts and incorporating immunobiomarkers in clinical trials is a challenge hereby set forth for clinicians and researchers.

Subacute sclerosing panencephalitis and immune thrombocytopenia: More than a coincidence?

Subacute sclerosing panencephalitis (SSPE) is a progressive disease caused by persistent measles virus (MV). It has an incidence of 0.4-2.0/million in Turkey. Immune thrombocytopenia (ITP) is a bleeding disorder whose estimated incidence is 4.2/100.000 person/years in the pediatric age group. We observed three cases with ITP in our cohort of 315 pediatric SSPE cases, an incidence higher than coincidentally expected in the general population. We hypothesize an association between SSPE and ITP. Our three cases had measles 1-2 years before the onset of ITP and 8-10 years before first symptoms of SSPE. A common immunogenetic background creating susceptibility to infection and autoimmunity might play a role. Alternatively, chronic antigenic stimulation by the MV leading to synthesis of cross-reacting antibodies against platelets, or treatment of ITP with immunoglobulins or steroids might affect or alter the development and manifestation of SSPE. The co-occurrence of these two disorders of viral and immune pathogenesis may draw attention to similar observations and provide clues for their mechanisms.

Important role of mast cells in multiple sclerosis

Autoimmunity is a disease that occurs when the body tissue is attacked by its own immune system. Multiple sclerosis (MS) is an autoimmune illness which triggers neurological progressive and persistent functions. MS is associated with an abnormal B-cell response and upregulation of T-cell reactivity against a multitude of antigens. Mast cells are the first line of the innate immune system and act by degranulating and secreting chemical mediators and cytokines. Their participation on the central nervous system has been recognized since the beginning of the last century. They have an important role in autoimmune disease, including MS where they mediate inflammation and demyelinization by presenting myelin antigens to T cells or disrupting the blood-brain barrier and permitting entry of inflammatory cells and cytokines. The participation of mast cells in MS is demonstrated by gene overexpression of chemical mediators and inflammatory cytokines. Here we report the relationship and involvement between mast cells and multiple sclerosis.

Expression patterns of micro-RNAs 146a, 181a, and 155 in subacute sclerosing panencephalitis

Subacute sclerosing panencephalitis is caused by persistent brain infection of mutated virus, showing inflammation, neurodegeneration, and demyelination. Although many factors are emphasized in the pathogenesis of subacute sclerosing panencephalitis, the exact mechanism of neurodegeneration remains unknown. Micro-RNAs are small, noncoding RNAs that regulate gene expression at the posttranscriptional levels. Micro-RNAs are essential for normal immune system development; besides they are also implicated in the pathogenesis of many chronic inflammatory disorders. The aim of this study is to investigate the expression patterns of micro-RNAs 146a, 181a, and 155 in peripheral blood mononuclear cells of patients with subacute sclerosing panencephalitis. We enrolled 39 patients with subacute sclerosing panencephalitis and 41 healthy controls. Quantitative analysis of micro-RNAs 146a, 181a, and 155 were performed using specific stem-loop primers followed by real-time polymerase chain reaction. All of 3 micro-RNAs were upregulated in subacute sclerosing panencephalitis patients. In addition, the level of micro-RNA 155 expression was higher in stage 3 patients. But, micro-RNA 146a and 181a expression levels showed no association or correlation with clinically relevant data. Alteration of peripheral blood mononuclear cell micro-RNAs in subacute sclerosing panencephalitis may shed new light on the pathogenesis of disease and may contribute to the aberrant systemic rise in mRNA levels in subacute sclerosing panencephalitis.

Dynamic changes of Foxp3(+) regulatory T cells in spleen and brain of canine distemper virus-infected dogs

Canine distemper virus (CDV) infection causes immunosuppression and demyelinating leukoencephalitis in dogs. In viral diseases, an ambiguous function of regulatory T cells (Treg), with both beneficial effects by reducing immunopathology and detrimental effects by inhibiting antiviral immunity, has been described. However, the role of Treg in the pathogenesis of canine distemper remains unknown. In order to determine the effect of CDV upon immune homeostasis, the amount of Foxp3(+) Treg in spleen and brain of naturally infected dogs has been determined by immunohistochemistry. In addition, splenic cytokine expression has been quantified by reverse transcriptase polymerase chain reaction. Splenic depletion of Foxp3(+) Treg was associated with an increased mRNA-expression of tumor necrosis factor and decreased transcription of interleukin-2 in the acute disease phase, indicative of disturbed immunological counter regulation in peripheral lymphoid organs. In the brain, a lack of Foxp3(+) Treg in predemyelinating and early demyelinating lesions and significantly increased infiltrations of Foxp3(+) Treg in chronic demyelinating lesions were observed. In conclusion, disturbed peripheral and CNS immune regulation associated with a reduction of Treg represents a potential prerequisite for excessive neuroinflammation and early lesion development in canine distemper leukoencephalitis.

Pediatric reference ranges for proinflammatory and anti-inflammatory cytokines in cerebrospinal fluid and serum by multiplexed immunoassay

To define cytokine concentrations and detectability in children with noninflammatory neurological disorders (NIND). The multiplex bead assay technology was used for simultaneous measurement of 34 soluble cytokines/chemokines in cerebrospinal fluid (CSF) from 73 NIND. Sera from 36 healthy children and 37 NIND also were analyzed. In CSF, CXCL10 had the highest concentration; CCL2, CXCL10, and interleukin (IL)-6 were detectable in all samples, and CXCL8, CCL22, CXCL1, IL-16, and IL-1 receptor antagonist were found in ≥50% of the samples. In serum, CXCL1 had the highest concentration; sIL-2Ra, CXCL1, CXCL10, and CCL22 were detectable in all samples, and CCL2, IL-12, CCL5, and granulocyte monocyte colony-stimulating factor (GM-CSF) were found in ≥50% of the samples. The mean CSF:serum ratio for CCL2 was several-fold higher than the rest, with the CXCL10 and CXCL8 ratios also >1. Intercorrelations between CSF cytokines included CCL2 versus CXCL8 and IL-6, and CXCL1 versus CCL22, reflecting both T-helper-1 (Th1)/Th1 and Th1/Th2 relations. Serum correlations included CCL11 versus CCL2, GM-CSF, and IL-4. For serum cytokines, the agreement between healthy children and NIND was good, with the exception of higher CCL4 in NIND. Cytokines in children varied greatly in concentration and detectability, with chemokines predominating in the CSF. These data allow investigators to select their own kit cytokines, instead of manufacturer-selected cytokines, for greater cost-effectiveness and interpretability.

Measles virus infection of the CNS: human disease, animal models, and approaches to therapy

Viral infections of the central nervous system(CNS) mostly represent clinically important, often life-threatening complications of systemic viral infections. After acute measles, CNS complications may occur early (acute postinfectious measles encephalitis, APME) or after years of viral persistence (subacute sclerosing panencephalitis, SSPE). In spite of a presumably functional cell-mediated immunity and high antiviral antibody titers, an immunological control of the CNS infection is not achieved in patients suffering from SSPE. There is still no specific therapy for acute complications and persistent MV infections of the CNS. Hamsters, rats, and (genetically unmodified and modified) mice have been used as model systems to study mechanisms of MV-induced CNS infections. Functional CD4+ and CD8+ T cells together with IFN-gamma are required to overcome the infection. With the help of recombinant measles viruses and mice expressing endogenous or transgenic receptors, interesting aspects such as receptor-dependent viral spread and viral determinants of virulence have been investigated. However, many questions concerning the lack of efficient immune control in the CNS are still open. Recent research opened new perspectives using specific antivirals such as short interfering RNA (siRNA) or small molecule inhibitors. Inspite of obvious hurdles, these treatments are the most promising approaches to future therapies.