Induction of brain-infiltrating T-bet–expressing B cells in multiple sclerosis

Objective: Results from anti-CD20 therapies demonstrate that B- and T-cell interaction is a major driver of multiple sclerosis (MS). The local presence of B-cell follicle-like structures and oligoclonal bands in MS patients indicates that certain B cells infiltrate the central nervous system (CNS) to mediate pathology. Which peripheral triggers underlie the development of CNS-infiltrating B cells is not fully understood. Methods: Ex vivo flow cytometry was used to assess chemokine receptor profiles of B cells in blood, cerebrospinal fluid, meningeal, and brain tissues of MS patients (n = 10). Similar analyses were performed for distinct memory subsets in the blood of untreated and natalizumab-treated MS patients (n = 38). To assess T-bet(CXCR3)+ B-cell differentiation, we cultured B cells from MS patients (n = 21) and healthy individuals (n = 34) under T helper 1- and TLR9-inducing conditions. Their CNS transmigration capacity was confirmed using brain endothelial monolayers. Results: CXC chemokine receptor 3 (CXCR3)-expressing B cells were enriched in different CNS compartments of MS patients. Treatment with the clinically effective drug natalizumab prevented the recruitment of CXCR3high IgG1+ subsets, corresponding to their increased ability to cross CNS barriers in vitro. Blocking of interferon-γ (IFNγ) reduced the transmigration potential and antigen-presenting function of these cells. IFNγ-induced B cells from MS patients showed increased T-bet expression and plasmablast development. Additional TLR9 triggering further upregulated T-bet and CXCR3, and was essential for IgG1 switching. Interpretation: This study demonstrates that T-bethigh IgG1+ B cells are triggered by IFNγ and TLR9 signals, likely contributing to enhanced CXCR3-mediated recruitment and local reactivity in the CNS of MS patients. ANN NEUROL 2019

Infliximab treatment in pathology-confirmed neurosarcoidosis

OBJECTIVE: To assess the efficacy and risks of treatment with infliximab (anti-tumor necrosis factor alpha) in pathology-confirmed neurosarcoidosis. METHODS: In a retrospective study in 2 tertiary referral centers in the Netherlands, we analyzed clinical characteristics, complications, and outcome of patients with neurosarcoidosis treated with infliximab. RESULTS: Twenty-eight patients were identified with a mean age of 42 years. Neurosarcoidosis presented with a cerebral parenchymal localization in 16 (59%), pituitary gland/hypothalamic sarcoidosis in 15 (54%), peripheral nerve involvement in 12 (43%), and chronic meningitis in 11 patients (41%). Initial treatment response after the start of infliximab was complete remission in 6 (21%) and improvement in 14 (50%), whereas 7 patients had stable disease (25%), and 1 (4%) deteriorated and died. At the end of follow-up, with a median of 32 months, 5 patients (18%) had died, and 2 (40%) were using infliximab at the time of death. Tapering or discontinuation of corticosteroids without a relapse was achieved in 19 of 28 patients (68%). In patients with decreasing dosing or discontinuation of infliximab, a relapse occurred in 5 of 19 patients (26%). Complications of infliximab were reported in 10 of 28 patients (36%) and mainly consisted of infections in 8 (29%). CONCLUSION: Infliximab is an effective treatment in neurosarcoidosis leading to remission or improvement in 70%. The mortality rate in infliximab-treated patients was substantial, indicating the severity of disease and treatment-associated complications. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that in people with pathology-confirmed neurosarcoidosis, infliximab is beneficial

The association of Epstein-Barr virus infection with CXCR3+ B-cell development in multiple sclerosis impact of immunotherapies

Epstein-Barr virus (EBV) infection of B cells is associated with increased multiple sclerosis (MS) susceptibility. Recently, we found that CXCR3-expressing B cells preferentially infiltrate the central nervous system of MS patients. In chronic virus-infected mice, these types of B cells are sustained and show increased antiviral responsiveness. How EBV persistence in B cells influences their development remains unclear. First, we analyzed ex vivo B-cell subsets from MS patients who received autologous bone marrow transplantation (n=9), which is often accompanied by EBV reactivation. The frequencies of non-class-switched and class-switched memory B cells were reduced at 3-7 months, while only class-switched B cells returned back to baseline at 24-36 months post-transplantation. At these time points, EBV DNA load positively correlated to the frequency of CXCR3+ , and not CXCR4+ or CXCR5+ , class-switched B cells. Second, for CXCR3+ memory B cells trapped within the blood of MS patients treated with natalizumab (anti-VLA-4 antibody n=15), latent EBV infection corresponded to enhanced in vitro formation of anti-EBNA1 IgG-secreting plasma cells under germinal center-like conditions. These findings imply that EBV persistence in B cells potentiates brain-homing and antibody-producing CXCR3+ subsets in MS. This article is protected by copyright. All rights reserved

Brain-homing CD4+ T cells display glucocorticoid-resistant features in MS

OBJECTIVE: To study whether glucocorticoid (GC) resistance delineates disease-relevant T helper (Th) subsets that home to the CNS of patients with early MS. METHODS: The expression of key determinants of GC sensitivity, multidrug resistance protein 1 (MDR1/ABCB1) and glucocorticoid receptor (GR/NR3C1), was investigated in proinflammatory Th subsets and compared between natalizumab-treated patients with MS and healthy individuals. Blood, CSF, and brain compartments from patients with MS were assessed for the recruitment of GC-resistant Th subsets using fluorescence-activated cell sorting (FACS), quantitative polymerase chain reaction (qPCR), immunohistochemistry, and immunofluorescence. RESULTS: An MS-associated Th subset termed Th17.1 showed a distinct GC-resistant phenotype as reflected by high MDR1 and low GR expression. This expression ratio was further elevated in Th17.1 cells that accumulated in the blood of patients with MS treated with natalizumab, a drug that prevents their entry into the CNS. Proinflammatory markers C-C chemokine receptor 6, IL-23R, IFN-γ, and GM-CSF were increased in MDR1-expressing Th17.1 cells. This subset predominated the CSF of patients with early MS, which was not seen in the paired blood or in the CSF from patients with other inflammatory and noninflammatory neurologic disorders. The potential of MDR1-expressing Th17.1 cells to infiltrate brain tissue was confirmed by their presence in MS white matter lesions. CONCLUSION: This study reveals that GC resistance coincides with preferential CNS recruitment of pathogenic Th17.1 cells, which may hamper the long-term efficacy of GCs in early MS