Severe impairment of regulatory T-cells and Th1-lymphocyte polarization in patients with Gaucher disease

Characterization of peripheral blood T follicular helper (TFH) cells in patients with type 1 Gaucher disease and carriers

BACKGROUND

Gaucher disease (GD) is the most common autosomal recessive lipid storage disease. In this study, the changes in TFH cells and IL-4 and IL-21 cytokines in blood samples of GD patients, carriers and healthy volunteers were investigated.

METHODS

Two pretreatment type 1 GD patients, 20 currently treated type 1 GD patients, 6 carriers, and 27 healthy volunteers were enrolled in the study. TFH cell (CD45RA^-CD4⁺CXCR5⁺) number, phenotype (PD1, ICOS expression), and cytokine production (IL-21, IL-4) were assessed via flow cytometric assays.

RESULTS

No significant differences were found between the groups with respect to the number, frequency and PD1 or ICOS expression of TFH cells between healthy controls, patients and carriers. However, IL-4⁺ TFH cells were significantly reduced both in percent and number in the treated GD patients compared with healthy controls (p < 0.05). Interestingly, the IL-21⁺ TFH cell number was increased in treated GD patients. When TFH cells were examined based on CXCR3 expression, the frequency of the PD1⁺Th17-Th2-like fraction (CXCR3^-) was found to be significantly increased in treated GD patients.

CONCLUSION

To our knowledge, this is the first study to assess TFH cells in GD patients, and to show that the production of IL-4 and IL-21 by TFH cells and their subsets may be altered in type 1 GD patients.

C-X-C Motif Chemokine Ligand 9 and Its CXCR3 Receptor Are the Salt and Pepper for T Cells Trafficking in a Mouse Model of Gaucher Disease

Gaucher disease is a lysosomal storage disease, which happens due to mutations in GBA1/Gba1 that encodes the enzyme termed as lysosomal acid β-glucosidase. The major function of this enzyme is to catalyze glucosylceramide (GC) into glucose and ceramide. The deficiency of this enzyme and resultant abnormal accumulation of GC cause altered function of several of the innate and adaptive immune cells. For example, augmented infiltration of T cells contributes to the increased production of pro-inflammatory cytokines, (e.g., IFNγ, TNFα, IL6, IL12p40, IL12p70, IL23, and IL17A/F). This leads to tissue damage in a genetic mouse model (Gba1^9V/-) of Gaucher disease. The cellular mechanism(s) by which increased tissue infiltration of T cells occurs in this disease is not fully understood. Here, we delineate role of the CXCR3 receptor and its exogenous C-X-C motif chemokine ligand 9 (CXCL9) in induction of increased tissue recruitment of CD4⁺ T and CD8⁺ T cells in Gaucher disease. Intracellular FACS staining of macrophages (Mϕs) and dendritic cells (DCs) from Gba1^9V/- mice showed elevated production of CXCL9. Purified CD4⁺ T cells and the CD8⁺ T cells from Gba1^9V/- mice showed increased expression of CXCR3. Ex vivo and in vivo chemotaxis experiments showed CXCL9 involvement in the recruitment of Gba1^9V/- T cells. Furthermore, antibody blockade of the CXCL9 receptor (CXCR3) on T cells caused marked reduction in CXCL9- mediated chemotaxis of T cells in Gba1^9V/- mice. These data implicate abnormalities of the CXCL9-CXCR3 axis leading to enhanced tissue recruitment of T cells in Gaucher disease. Such results provide a rationale for blockade of the CXCL9/CXCR3 axis as potential new therapeutic targets for the treatment of inflammation in Gaucher disease.

Downregulation of B regulatory cells and upregulation of T helper 1 cells in children with Gaucher disease undergoing enzyme replacement therapy

Gaucher disease (GD) involves a broad spectrum of immunological cells, including T helper (Th) cells and regulatory B cells (Bregs), which function to resolve the immune response and inhibit excessive inflammation. This study aimed to explore T helper cells, B cells, and Bregs in GD children undergoing enzyme replacement therapy (ERT). Our study included 20 GD patients; six patients were categorized as type 1 and 14 as type 3 GD. All patients were on regular ERT. Twenty healthy children were enrolled as controls. All patients and controls were subjected to complete blood analysis, abdominal ultrasound, and flow cytometric detection of T helper cells, B cells, and Bregs. Despite undergoing ERT, CD4+ T helper lymphocytes and Bregs were still significantly lower in patients with GD compared with the controls. Th1 and B cells were more in the patients than in the healthy controls. Lower levels of Bregs were found in type 3, compared with type 1 patients. Increased platelet count was directly associated with increased levels of Bregs and lower levels of B cells. Elevated children's height was also accompanied by decreasing levels of Th1. Our results propose that ERT in GD is associated with partial improvement in immune status, and long-term ERT might be needed for the restoration of the desired immune response levels. Levels of Bregs and Th1 can be employed for monitoring improvement of immune status in GD patients undergoing ERT.

Challenges in the diagnosis of hemophagocytic lymphohistiocytosis: Recommendations from the North American Consortium for Histiocytosis (NACHO)

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of pathologic immune activation, often associated with genetic defects of lymphocyte cytotoxicity. Though a distinctive constellation of features has been described for HLH, diagnosis remains challenging as patients have diverse presentations associated with a variety of triggers. We propose two concepts to clarify how HLH is diagnosed and treated: within the broader syndrome of HLH, "HLH disease" should be distinguished from "HLH disease mimics" and HLH subtypes should be categorized by specific etiologic associations, not the ambiguous dichotomy of "primary" and "secondary." We provide expert-based advice regarding the diagnosis and initiation of treatment for patients with HLH, rooted in improved understanding of its pathophysiology.

β-Glycosphingolipids as Mediators of Both Inflammation and Immune Tolerance: A Manifestation of Randomness in Biological Systems

Plasticity in biological systems is attributed to the combination of multiple parameters which determine function. These include genotypic, phenotypic, and environmental factors. While biological processes can be viewed as ordered and sequential, biological randomness was suggested to underline part of them. The present review looks into the concept of randomness in biological systems by exploring the glycosphingolipids-NKT cells example. NKT cells are a unique subset of regulatory lymphocytes which play a role in both inflammation and tolerance. Glycosphingolipids promote an immune balance by changing different arms of the immune system in opposing environments. Traditional immunology looks at skewing the immune system into different directions by different types of activation of the same cell stimulation of different cells subsets, use of different ligands, or different the effect of different immune environments. While these may explain some of the effects, the lack of consistency and opposing results under similar settings may involve randomness which may also be part of real life effects of immunomodulatory agents. It means that several of the biological processes, cannot be explained by simple linear models, and may involve more complex concepts. The application for these concepts for improving therapies to patients with Gaucher disease are discussed. SUMMARY  The use of different ligands that target a variety of cell subsets in different immune environments may underlie differences in the functionality of NKT cells and their variability in response to NKT-based therapies. The novel concept of randomness in biology means that several biological processes cannot be solely explained by simple linear models and may instead involve much more complicated schemes of random disorder. These may have implications on future design of therapeutic regimens for improving the response to current treatments.

Down-regulation of Regulatory T-cells in Children With Gaucher Disease Under Enzyme Replacement Therapy

Gaucher disease (GD) is one of the most important lysosomal storage disorders. T-lymphocytes perform and regulate many of the immune processes and play a major role in immune homeostasis. Studies have shown that GD causes impairment in T-lymphocyte functions, although the role and status of T-lymphocytes in GD are still under investigation. It is still not fully known how GD leads to the altered biochemical and immunological cellular functions observed in the disease. Our study aimed to evaluate the variations of regulatory T-lymphocytes (Tregs) in 20 Egyptian children with GD under enzyme replacement therapy, managed in Assiut University Hospitals. Tregs were detected using 3-color flow cytometric immunophenotyping, in which subpopulations of T-lymphocytes and the expression of CD4⁺ on their surfaces were gated. The expression of CD25⁺ was assessed on CD4⁺ cells with different gates to define CD4⁺CD25, CD4⁺CD25^+high, and CD4⁺CD25⁺ low cells. Then, CD4⁺CD25^+highFoxp3⁺cells and MFI of Foxp3⁺ expression on CD4⁺CD25⁺ high were determined. We found the levels of CD4⁺CD25⁺/CD4⁺, CD4⁺CD25⁺high/CD4⁺, CD4⁺CD25^+highFoxp3⁺ Tregs, and median fluorescence intensity of Foxp3⁺ expression on CD4⁺CD25^+high were significantly lower in children with GD compared to healthy controls. In conclusion, our data showed significantly decreased regulatory T-lymphocytes in children with GD. The reduced effect of Tregs may have a role in the pathogenesis of immune dysregulation in children with GD. The relationship of these cells to immune disorders in GD children remains to be determined. Therefore, we recommend further studies to elucidate the role and function of Tregs in GD and its potential role in the disease phenotype, as well as how it is affected by electrical resistivity tomography.

Activated and Memory T Lymphocytes in Children with Gaucher Disease

Gaucher disease (GD) is the most prevalent lysosomal storage disorder. Gaucher disease is associated with remarkable alterations in the immune system, and GD patients are more susceptible to infections and are at a higher risk of developing autoimmune disorders and malignancies. In a case-control study, we used three-color flow cytometric immunophenotyping for determination of the frequency of lymphocyte subpopulations and activated T lymphocytes among 18 children with GD1 under enzyme replacement therapy managed in Assiut University Hospitals. We found significant increases in the frequencies of total lymphocytes, CD19⁺, CD3⁺, CD4⁺, and CD8⁺ in children with GD1 when compared to healthy control. The frequencies of activated T lymphocytes (CD3⁺HLA-DR⁺), activated T-helper cells (CD4⁺HLA-DR⁺), and activated T-suppressor/cytotoxic cells (CD8⁺HLA-DR⁺) were significantly higher in GD1 as compared to healthy children. Our data show that the increased proportion of activated T lymphocytes in children with GD1 raises the issue of their possible involvement in the pathogenesis of the immune dysfunction seen in these patients. Our data suggested that the activated T lymphocytes could play a role in the clinical course of GD1. The relationship of these cells to immune disorders in GD1 children remains to be determined.

Compounds of the sphingomyelin-ceramide-glycosphingolipid pathways as secondary messenger molecules: new targets for novel therapies for fatty liver disease and insulin resistance

The compounds of sphingomyelin-ceramide-glycosphingolipid pathways have been studied as potential secondary messenger molecules in various systems, along with liver function and insulin resistance. Secondary messenger molecules act directly or indirectly to affect cell organelles and intercellular interactions. Their potential role in the pathogenesis of steatohepatitis and diabetes has been suggested. Data samples collected from patients with Gaucher's disease, who had high levels of glucocerebroside, support a role for compounds from these pathways as a messenger molecules in the pathogenesis of fatty liver disease and diabetes. The present review summarizes some of the recent data on the role of glycosphingolipid molecules as messenger molecules in various physiological and pathological conditions, more specifically including insulin resistance and fatty liver disease.

Long-term response in biochemical markers of bone turnover during enzyme replacement therapy in a case-series of patients with Gaucher disease type I from Northern Greece

BACKGROUND

Gaucher disease (GD) is a lysosomal storage disorder characterized by severe skeletal complications. Bone complications are an important cause of morbidity of GD and are thought to result from imbalance in bone remodeling. The objective of this case series was to analyze the long-term effect of enzyme replacement therapy on chemokines MIP-1a and MIP-1b, cytokines IL-3, IL-6, IL-10, and IL-12, osteoprotegerin (OPG) and osteocalcin (BGP), chitotriosidase, quantitative ultrasound sonography (QUS), bone magnetic resonance imaging (MRI) and dual-energy X-ray absorptiometry (DXA) in patients with GD in Northern Greece. In addition, the study aimed in investigating possible relationship between the above mentioned parameters.

PATIENTS AND METHODS

Seven patients with GD type I (three males and four females) were included in the study. Mean age was 26.29 ± 15.34 years (range 7-47 years). Six patients were receiving enzyme replacement therapy (ERT), with 40-60 IU/kg of imiglucerase weekly, for a mean period of 36 months prior to study initiation. One patient started ERT after his inclusion in the study. The levels of MIP-1a, MIP-1b, IL-3, IL-6, IL-10, IL-12, OPG, BGP, chitotriosidase, bone imaging parameters assessed with two different techniques (QUS and DXA) and MRI data were estimated at baseline (T₀) and after two years on ERT.

RESULTS

Chitotriosidase, MIP-1a, and IL-6 levels decreased in all patients after two years of ERT (p =0.05). In contrast, OPG and BGP levels increased (p =0.04 and p =0.02, respectively). Bone mineral density (BMD) demonstrated a progressive improvement with regards to the Z-score in all patients (p =0.05). The decrease in the plasma levels of MIP-1a strongly correlated with a decrease in the plasma levels of chitotriosidase. Additionally, decreased plasma levels of IL-6 were correlated with increased Z-score both at baseline (T₀) as well as two years later, in all patients. There was no correlation between MRI findings and any inflammatory biomarker.

CONCLUSIONS

Measurement of serum markers in patients with GD under ERT could be used as an auxiliary tool in the monitoring of bone involvement, in combination with MRI imaging and BMD. However, larger studies involving higher numbers of GD patients are needed to confirm these conclusions. Hippokratia 2016, 20(2): 153-159.