RESUMO
Eculizumab (ECU), a C5 complement inhibitor, is approved to treat acetylcholine receptor autoantibody positive generalized myasthenia gravis (AChR MG). The clinical effect of ECU relies on inhibition of the terminal complement complex; however, the effect of ECU on lymphocytes is largely unknown. We evaluated innate and adaptive immunity among AChR MG patients (N = 3) before ECU and ≥3 months later while on stable therapy, and found reduced activation markers in memory CD4+ T cell subsets, increased regulatory T cell populations, and reduced frequencies of CXCR5+HLA-DR+CCR7+ Tfh subsets and CD11b+ migratory memory B cells. We observed increases within CD8+ T cell subsets that were terminally differentiated and senescent. Our data suggest complement inhibition with ECU modulates the adaptive immunity in patients with MG, consistent with preclinical data showing changes in complement-mediated signaling by T- and antigen-presenting cells. These findings extend our understanding of ECU's mechanism of action when treating patients with MG.
Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Linfócitos B/efeitos dos fármacos , Inativadores do Complemento/uso terapêutico , Miastenia Gravis/tratamento farmacológico , Linfócitos T/efeitos dos fármacos , Imunidade Adaptativa/efeitos dos fármacos , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Miastenia Gravis/imunologiaRESUMO
BACKGROUND: The immunopathology of autoimmune seronegative myasthenia gravis (SN MG) is poorly understood. Our objective was to determine immune profiles associated with a diagnosis of SN MG. METHODS: We performed high-dimensional flow cytometry on blood samples from SN MG patients (N = 68), healthy controls (N = 46), and acetylcholine receptor antibody (AChR+) MG patients (N = 27). We compared 12 immune cell subsets in SN MG to controls using logistic modeling via a discovery-replication design. An exploratory analysis fit a multinomial model comparing AChR+ MG and controls to SN MG. RESULTS: An increase in CD19+ CD20- CD38hi plasmablast frequencies was associated with lower odds of being a SN MG case in both the discovery and replication analyses (discovery P-value = .0003, replication P-value = .0021). Interleukin (IL) -21 producing helper T cell frequencies were associated with a diagnosis of AChR+ MG (P = .004). CONCLUSIONS: Reduced plasmablast frequencies are strongly associated with a SN MG diagnosis and may be a useful diagnostic biomarker in the future.
Assuntos
Autoanticorpos/sangue , Miastenia Gravis/sangue , Plasmócitos/citologia , Receptores Colinérgicos/sangue , Adulto , Idoso , Biomarcadores/sangue , Feminino , Citometria de Fluxo/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Miastenia Gravis/diagnóstico , Receptores Colinérgicos/imunologia , Adulto JovemRESUMO
A detailed understanding of the role of Tfh cells in MuSK-antibody positive myasthenia gravis (MuSK-MG) is lacking. We characterized phenotype and function of Tfh cells in MuSK-MG patients and controls. We found similar overall Tfh and follicular regulatory (Tfr) T cell frequencies in MuSK-MG and healthy controls, but MuSK-MG patients exhibited higher frequencies of Tfh17 cells and a higher ratio of Tfh:Tfr cells. These results suggest imbalanced Tfh cell regulation, further supported by increased frequencies of CD4 T cells co-producing IL-21/IL-17 and IL-17/IFN-γ, and increased Tfh-supported IgG production. These results support a role for Tfh cell dysregulation in MuSK-MG immunopathology.
Assuntos
Autoanticorpos/imunologia , Mediadores da Inflamação/imunologia , Interleucina-17/imunologia , Miastenia Gravis/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Adulto , Idoso , Autoanticorpos/sangue , Técnicas de Cocultura , Feminino , Humanos , Mediadores da Inflamação/sangue , Interleucina-17/sangue , Masculino , Pessoa de Meia-Idade , Miastenia Gravis/sangue , Linfócitos T Auxiliares-Indutores/metabolismo , Adulto JovemRESUMO
IL-17 producing CD4 T cells (Th17) cells increase significantly with disease severity in myasthenia gravis (MG) patients. To suppress the generation of Th17 cells, we examined the effect of inhibiting retinoic acid receptor-related-orphan-receptor-C (RORγ), a Th17-specific transcription factor critical for differentiation. RORγ inhibition profoundly reduced Th17 cell frequencies, including IFN-γ and IL-17 co-producing pathogenic Th17 cells. Other T helper subsets were not affected. In parallel, CD8 T cell subsets producing IL-17 and IL-17/IFN-γ were increased in MG patients and inhibited by the RORγ inhibitor. These findings provide rationale for exploration of targeted Th17 therapies, including ROR-γ inhibitors, to treat MG patients.
Assuntos
Fatores Imunológicos/farmacologia , Miastenia Gravis/imunologia , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/antagonistas & inibidores , Células Th17/efeitos dos fármacos , Células Th17/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Autoanticorpos/imunologia , Autoantígenos/imunologia , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/imunologia , Feminino , Humanos , Interleucina-17/imunologia , Masculino , Pessoa de Meia-Idade , Receptores Colinérgicos/imunologiaRESUMO
Muscle specific tyrosine kinase antibody positive myasthenia gravis (MuSK- MG) is characterized by autoantibodies against the MuSK protein of the neuromuscular junction resulting in weakness of bulbar and proximal muscles. We previously demonstrated that patients with MuSK-MG have increased pro-inflammatory Th1 and Th17 responses. Tacrolimus, an immunosuppressant used in AChR-MG and transplantation patients, inhibits T cell responses through interference with IL-2 transcription. The therapeutic efficacy and immunological effect of tacrolimus in MuSK-MG is unclear. In the current study we examined the proliferation, phenotype and cytokine production of CD4+ and CD8+ T cells in peripheral blood mononuclear cells of MuSK-MG following a 3-day in vitro culture with or without tacrolimus. We determined that tacrolimus profoundly suppressed CD4 and CD8 T cell proliferation and significantly suppressed Th1 and Th17 responses, as demonstrated by a reduced frequency of IFN-γ, IL-2, and IL-17 producing CD4 T cells and reduced frequencies of IFN-γ and IL-2 producing CD8 T cells. Tacrolimus also inhibits pathogenic Th17 cells coproducing IL-17 and IFN-γ. In addition, tacrolimus suppressed follicular T helper cell (Tfh) and regulatory T helper cell (Treg) subsets. These findings provide preliminary support for tacrolimus as a potential alternative immunosuppressive therapy for MuSK-MG.