Circulating CXCR5+ natural killer cells are expanded in patients with myasthenia gravis

Differential alterations of CXCR3, CXCR5 and CX3CR1 in patients with immune thrombocytopenia

As a versatile element for maintaining homeostasis, the chemokine system has been reported to be implicated in the pathogenesis of immune thrombocytopenia (ITP). However, research pertaining to chemokine receptors and related ligands in adult ITP is still limited. The states of several typical chemokine receptors and cognate ligands in the circulation were comparatively assessed through various methodologies. Multiple variable analyses of correlation matrixes were conducted to characterize the correlation signatures of various chemokine receptors or candidate ligands with platelet counts. Our data illustrated a significant decrease in relative CXCR3 expression and elevated plasma levels of CXCL4, 9-11, 13, and CCL3 chemokines in ITP patients with varied platelet counts. Flow cytometry assays revealed eminently diminished CXCR3 levels on T and B lymphocytes and increased CXCR5 on cytotoxic T cell (Tc) subsets in ITP patients with certain platelet counts. Meanwhile, circulating CX3CR1 levels were markedly higher on T cells with a concomitant increase in plasma CX3CL1 level in ITP patients, highlighting the importance of aberrant alterations of the CX3CR1-CX3CL1 axis in ITP pathogenesis. Spearman's correlation analyses revealed a strong positive association of peripheral CXCL4 mRNA level, and negative correlations of plasma CXCL4 concentration and certain chemokine receptors with platelet counts, which might serve as a potential biomarker of platelet destruction in ITP development. Overall, these results indicate that the differential expression patterns and distinct activation states of peripheral chemokine network, and the subsequent expansion of circulating CXCR5+ Tc cells and CX3CR1+ T cells, may be a hallmark during ITP progression, which ultimately contributes to thrombocytopenia in ITP patients.

Therapeutic potential of natural killer cells in neuroimmunological diseases

Natural killer (NK) cells, a major component of the innate immune system, have prominent immunoregulatory, antitumor proliferation, and antiviral activities. NK cells act as a double-edged sword with therapeutic potential in neurological autoimmunity. Emerging evidence has identified NK cells are involved in the development and progression of neuroimmunological diseases such as multiple sclerosis, neuromyelitis optica spectrum disorders, autoimmune encephalitis, Guillain-Barré Syndrome, chronic inflammatory demyelinating polyneuropathy, myasthenia gravis, and idiopathic inflammatory myopathy. However, the regulatory mechanisms and functional roles of NK cells are highly variable in different clinical states of neuroimmunological diseases and need to be further determined. In this review, we summarize the evidence for the heterogenic involvement of NK cells in the above conditions. Further, we describe cutting-edge NK-cell-based immunotherapy for neuroimmunological diseases in preclinical and clinical development and highlight challenges that must be overcome to fully realize the therapeutic potential of NK cells.

Serum amyloid A facilitates expansion of CD4+ T cell and CD19+ B cell subsets implicated in the severity of myasthenia gravis patients

Serum amyloid A (SAA) is a clinically useful inflammatory marker involved in the pathogenesis of autoimmune diseases. This study aimed to explore the SAA levels in a cohort of patients with myasthenia gravis (MG) in relation to disease-related clinical parameters and myasthenic crisis (MC) and elucidate the effects of SAA on immune response. A total of 82 MG patients including 50 new-onset MG patients and 32 MC patients were enrolled in this study. Baseline data and laboratory parameters of all enrolled MG patients were routinely recorded through electronic medical systems. SAA levels were measured by enzyme-linked immunosorbent assay (ELISA) kit. CD4+ T and CD19+ B cell subsets were analyzed by flow cytometry. In vitro, human recombinant SAA (Apo-SAA) was applied to stimulate peripheral blood mononuclear cells (PBMCs) from MG patients to observe the effect on T and B cell differentiation. Our results indicated that SAA levels in new-onset MG patients were higher than those in controls and were positively correlated with QMG score, MGFA classification, plasmablast cells, IL-6, and IL-17 levels. Subgroup analysis revealed that SAA levels were increased in generalized MG (GMG) patients than in ocular MG (OMG), as well as elevated in late-onset MG (LOMG) than in early-onset MG (EOMG) and higher in MGFA III/IV compared with MGFA I/II. The ROC curve demonstrated that SAA showed good diagnostic value for MC, especially when combined with NLR. In vitro, Apo-SAA promoted the Th1 cells, Th17 cells, plasmablast cells, and plasma cells differentiation in MG PBMCs. The present findings suggested that SAA was increased in MG patients and promoted expansion of CD4+ T cell and CD19+ B cell subsets, which implicated in the severity of MG patients.

The investigation of killer-cell immunoglobulin-like receptors (KIRs) and their HLA ligands in Iranian patients with myasthenia gravis

BACKGROUND

Myasthenia gravis (MG) is a disabling disease with the underlying pathophysiology of auto-antibodies attacking the postsynaptic acetylcholine receptors of neuromuscular junctions causing muscle weakness. Natural killer (NK) cells are innate immune cells that play an important regulative role in immune responses. The human killer-cell immunoglobulin-like receptors (KIRs) family is one of the receptors on NK cells that can either activate or inhibit NK cells. This study aimed to assess the possible role of KIR and their human leukocyte antigen (HLA) ligand genes susceptibility to MG in Iranian patients.

METHOD

One hundred and sixty-three patients with MG diagnosis based on the presence of clinical symptoms and laboratory tests and 400 healthy volunteers were studied. We used the polymerase chain reaction (PCR) technique for genotyping 15 KIRs and 5 HLA genes.

RESULTS

The results demonstrated that there was no significant difference in the frequency of KIR genes and inhibitory KIR genotypes between controls and patients. In MG patients, HLA-C1Asn80 was significantly less frequent than in matched controls. The frequency of HLA genotype number 7 was significantly lower in MG cases, compared to the controls. Analysis of activating KIR genotypes showed that genotype number 10 was significantly less frequent in MG cases than in matched controls.

CONCLUSION

Our results suggest that the presence HLA-C1Asn80 might play a protective role against the pathogenesis of MG. The significantly decreased prevalence of one activating KIR genotype and one of the HLA genotypes in MG cases suggest that these genotypes can reduce the risk of MG development. To specifically reveal the impact of KIR and HLA in MG, more studies are required.