Association of Clinical Relapses With Disease Outcomes in Multiple Sclerosis Patients Older Than 50 Years.

BACKGROUND AND OBJECTIVES: Relapse and MRI activity usually decline with aging but are replaced by progression independent of relapse activity (PIRA) in patients with multiple sclerosis (PwMS). However, several older PwMS continue to experience clinical relapses, and the impact on their disease remains undetermined. We aimed to determine the impact of an index relapse on disease outcomes in patients older than 50 years and to identify risk factors of disadvantageous outcomes. METHODS: We performed a secondary analysis from 3 prospective cohorts in Germany. We evaluated all PwMS 50 years and older with a relapse ≤60 days before a baseline visit and at least 18 months of follow-up compared with a control cohort of PwMS without a relapse. Patients were stratified according to age ("50-54" vs "55-59" vs "60+") or disease outcomes ("stable" vs "active" vs "progressive," according to the Lublin criteria). We analyzed relapses, MRI activity, relapse-associated worsening, and PIRA. Regression analysis was performed to evaluate the association of specific baseline risk factors and treatment regimen changes with disease outcomes at month 18. RESULTS: A total of 681 patients were included in the "relapse cohort" (50+: 361; 55+: 220; 60+: 100). The "control cohort" comprised 232 patients (50+: 117; 55+: 71; 60+: 44). Baseline epidemiologic parameters were balanced among cohorts and subgroups. We observed increased abundance of inflammatory activity and relapse-independent disability progression in the "relapse" vs "control" cohort. In the "relapse" cohort, we identified 273 patients as "stable" (59.7%), 114 patients as "active" (24.9%), and 70 patients as "progressive" (15.3%) during follow-up. Cardiovascular risk factors (CVRFs) and older age at baseline were identified as risk factors of progressive, whereas disease-modifying treatment (DMT) administration at baseline favored stable disease. DMT during follow-up was associated with stable over active, but not over progressive disease. DISCUSSION: A relapse-suggesting underlying active disease-in PwMS older than 50 years was associated with continued disease activity and increased risk of PIRA. Presence of CVRF and absence of DMT at baseline appeared as risk factors of disadvantageous disease courses. An escalation of DMT switch was associated with stable over active but not progressive disease.

K2P2.1 is a regulator of inflammatory cell responses in idiopathic inflammatory myopathies.

K2P2.1 (TREK1), a two-pore domain potassium channel, has emerged as regulator of leukocyte transmigration into the central nervous system. In the context of skeletal muscle, immune cell infiltration constitutes the pathogenic hallmark of idiopathic inflammatory myopathies (IIMs). However, the underlying mechanisms remain to be elucidated. In this study, we investigated the role of K2P2.1 in the autoimmune response of IIMs. We detected K2P2.1 expression in primary skeletal muscle and endothelial cells of murine and human origin. We observed an increased pro-inflammatory cell response, adhesion and transmigration by pharmacological blockade or genetic deletion of K2P2.1 in vitro and in in vivo myositis mouse models. Of note, our findings were not restricted to endothelial cells as skeletal muscle cells with impaired K2P2.1 function also demonstrated a strong pro-inflammatory response. Conversely, these features were abrogated by activation of K2P2.1 and improved the disease course of a myositis mouse model. In humans, K2P2.1 expression was diminished in IIM patients compared to non-diseased controls arguing for the translatability of our findings. In summary, K2P2.1 may regulate the inflammatory response of skeletal muscle. Further research is required to understand whether K2P2.1 could serve as novel therapeutic target.

Immune Response to Seasonal Influenza Vaccination in Multiple Sclerosis Patients Receiving Cladribine.

Cladribine has been approved for the treatment of multiple sclerosis (MS) and its administration results in a long-lasting depletion of lymphocytes. As lymphopenia is known to hamper immune responses to vaccination, we evaluated the immunogenicity of the influenza vaccine in patients undergoing cladribine treatment at different stages vs. controls. The antibody response in 90 cladribine-treated MS patients was prospectively compared with 10 control subjects receiving platform immunotherapy (NCT05019248). Serum samples were collected before and six months after vaccination. Response to vaccination was determined by the hemagglutination-inhibition test. Postvaccination seroprotection rates against influenza A were comparable in cladribine-treated patients and controls (H1N1: 94.4% vs. 100%; H3N2: 92.2% vs. 90.0%). Influenza B response was lower in the cladribine cohort (61.1% vs. 80%). The increase in geometric mean titers was lower in the cladribine group vs. controls (H1N1: +98.5 vs. +188.1; H3N2: +225.3 vs. +300.0; influenza B: +40.0 vs. +78.4); however, titers increased in both groups for all strains. Seroprotection was achieved irrespective of vaccination timing and lymphocyte subset counts at the time of vaccination in the cladribine cohort. To conclude, cladribine-treated MS patients can mount an adequate immune response to influenza independently of treatment duration and time interval to the last cladribine administration.

Effect of Previous Disease-Modifying Therapy on Treatment Effectiveness for Patients Treated With Ocrelizumab.

BACKGROUND AND OBJECTIVES: B cell-depleting antibodies were proven as effective strategy for the treatment of relapsing multiple sclerosis (RMS). The monoclonal antibody ocrelizumab was approved in 2017 in the United States and in 2018 in the European Union, but despite proven efficacy in randomized, controlled clinical trials, its effectiveness in the real-world setting remains to be fully elucidated. In particular, most study patients were treatment naive or switched from injectable therapies, whereas oral substances or monoclonal antibodies made up >1% of previous treatments. METHODS: We evaluated ocrelizumab-treated patients with RMS enrolled in the prospective cohorts at the University Hospitals Duesseldorf and Essen, Germany. Epidemiologic data at baseline were compared, and Cox proportional hazard models were applied to evaluate outcomes. RESULTS: Two hundred eighty patients were included (median age: 37 years, 35% male patients). Compared with using ocrelizumab as a first-line treatment, its use as a third-line therapy increased hazard ratios (HRs) for relapse and disability progression, whereas differences between first- vs second-line and second- vs third-line remained smaller. We stratified patients according to their last previous disease-modifying treatment and here identified fingolimod (FTY) (45 patients, median age 40 years, 33% male patients) as a relevant risk factor for ongoing relapse activity despite 2nd-line (HR: 3.417 [1.007-11.600]) or 3rd-line (HR: 5.903 [2.489-13.999]) ocrelizumab treatment, disability worsening (2nd line: HR: 3.571 [1.013-12.589]; 3rd line: HR: 4.502 [1.728-11.729]), and occurrence of new/enlarging MRI lesions (2nd line: HR: 1.939 [0.604-6.228]; 3rd line: HR: 4.627 [1.982-10.802]). Effects were persistent throughout the whole follow-up. Neither peripheral B-cell repopulation nor immunoglobulin G levels were associated with rekindling disease activity. DISCUSSION: Our prospectively collected observational data suggest suboptimal effectiveness of ocrelizumab in patients switching from FTY compared with those switching from other substances or having been treatment naive. These findings support previous studies indicating abated effectiveness of immune cell-depleting therapies following FTY treatment in patients with RMS. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that for patients with RMS, previous treatment with FTY compared with previous treatment with other immunomodulating therapies decreases the effectiveness of ocrelizumab.

Cladribine treatment improves cortical network functionality in a mouse model of autoimmune encephalomyelitis.

BACKGROUND: Cladribine is a synthetic purine analogue that interferes with DNA synthesis and repair next to disrupting cellular proliferation in actively dividing lymphocytes. The compound is approved for the treatment of multiple sclerosis (MS). Cladribine can cross the blood-brain barrier, suggesting a potential effect on central nervous system (CNS) resident cells. Here, we explored compartment-specific immunosuppressive as well as potential direct neuroprotective effects of oral cladribine treatment in experimental autoimmune encephalomyelitis (EAE) mice. METHODS: In the current study, we compare immune cell frequencies and phenotypes in the periphery and CNS of EAE mice with distinct grey and white matter lesions (combined active and focal EAE) either orally treated with cladribine or vehicle, using flow cytometry. To evaluate potential direct neuroprotective effects, we assessed the integrity of the primary auditory cortex neuronal network by studying neuronal activity and spontaneous synaptic activity with electrophysiological techniques ex vivo. RESULTS: Oral cladribine treatment significantly attenuated clinical deficits in EAE mice. Ex vivo flow cytometry showed that cladribine administration led to peripheral immune cell depletion in a compartment-specific manner and reduced immune cell infiltration into the CNS. Histological evaluations revealed no significant differences for inflammatory lesion load following cladribine treatment compared to vehicle control. Single cell electrophysiology in acute brain slices was performed and showed an impact of cladribine treatment on intrinsic cellular firing patterns and spontaneous synaptic transmission in neurons of the primary auditory cortex. Here, cladribine administration in vivo partially restored cortical neuronal network function, reducing action potential firing. Both, the effect on immune cells and neuronal activity were transient. CONCLUSIONS: Our results indicate that cladribine exerts a neuroprotective effect after crossing the blood-brain barrier independently of its peripheral immunosuppressant action.

Immunoadsorption versus double-dose methylprednisolone in refractory multiple sclerosis relapses.

OBJECTIVE: Intravenous methylprednisolone is the standard treatment for a multiple sclerosis relapse; however, this fails to improve symptoms in up to one quarter of patients. Immunoadsorption is an accepted treatment for refractory relapses, but prospective comparator-controlled studies are missing. METHODS: In this observational study, patients with steroid-refractory acute multiple sclerosis relapses receiving either six courses of tryptophan-immunoadsorption or double-dose methylprednisolone therapy were analysed. Outcomes were evaluated at discharge and three months later. Immune profiling of blood lymphocytes and proteomic analysis were performed by multi-parameter flow cytometry and Olink analysis, respectively (NCT04450030). RESULTS: 42 patients were enrolled (methylprednisolone: 26 patients; immunoadsorption: 16 patients). For determination of the primary outcome, treatment response was stratified according to relative function system score changes ("full/best" vs. "average" vs. "worse/none"). Upon discharge, the adjusted odds ratio for any treatment response ("full/best" + "average" vs. "worse/none") was 10.697 favouring immunoadsorption (p = 0.005 compared to methylprednisolone). At follow-up, the adjusted odds ratio for the best treatment response ("full/best" vs. "average" + "worse/none") was 103.236 favouring IA patients (p = 0.001 compared to methylprednisolone). Similar results were observed regarding evoked potentials and quality of life outcomes, as well as serum neurofilament light-chain levels. Flow cytometry revealed a profound reduction of B cell subsets following immunoadsorption, which was closely correlated to clinical outcomes, whereas methylprednisolone had a minimal effect on B cell populations. Immunoadsorption treatment skewed the blood cytokine network, reduced levels of B cell-related cytokines and reduced immunoglobulin levels as well as levels of certain coagulation factors. INTERPRETATION: Immunoadsorption demonstrated favourable outcomes compared to double-dose methylprednisolone. Outcome differences were significant at discharge and follow-up. Further analyses identified modulation of B cell function as a potential mechanism of action for immunoadsorption, as reduction of B cell subsets correlated with clinical improvement.

Deficiency of the Two-Pore Potassium Channel KCNK9 Impairs Intestinal Epithelial Cell Survival and Aggravates Dextran Sodium Sulfate-Induced Colitis.

BACKGROUND & AIMS: The 2-pore potassium channel subfamily K member 9 (KCNK9) regulates intracellular calcium concentration and thus modulates cell survival and inflammatory signaling pathways. It also was recognized as a risk allele for inflammatory bowel disease. However, it remains unclear whether KCNK9 modulates inflammatory bowel disease via its impact on immune cell function or whether its influence on calcium homeostasis also is relevant in intestinal epithelial cells. METHODS: Kcnk9-/- mice were challenged with 3% dextran sulfate sodium (DSS) to induce experimental acute colitis. Primary cultures of intestinal epithelial cells were generated, and expression of potassium channels as well as cytosolic calcium levels and susceptibility to apoptosis were evaluated. Furthermore, we evaluated whether KCNK9 deficiency was compensated by the closely related 2-pore potassium channel KCNK3 in vivo or in vitro. RESULTS: Compared with controls, KCNK9 deficiency or its pharmacologic blockade were associated with aggravated DSS-induced colitis compared with wild-type animals. In the absence of KCNK9, intestinal epithelial cells showed increased intracellular calcium levels and were more prone to mitochondrial damage and caspase-9-dependent apoptosis. We found that expression of KCNK3 was increased in Kcnk9-/- mice but did not prevent apoptosis after DSS exposure. Conversely, increased levels of KCNK9 in Kcnk3-/- mice were associated with an ameliorated course of DSS-induced colitis. CONCLUSIONS: KCNK9 enhances mitochondrial stability, reduces apoptosis, und thus supports epithelial cell survival after DSS exposure in vivo and in vitro. Conversely, its increased expression in Kcnk3-/- resulted in less mitochondrial damage and apoptosis and was associated with beneficial outcomes in DSS-induced colitis.

Immunological consequences of cladribine treatment in multiple sclerosis: A real-world study.

BACKGROUND: Cladribine is a synthetic deoxyadenosine analogue approved for the treatment of highly active relapsing multiple sclerosis (RMS). Cladribine is considered to be a semi-selective immune-reconstitution therapy (IRT) that induces long-term remission following short course of treatment. Here, we evaluated the effect of cladribine on immune cell reduction and reconstitution during the first two years of treatment. METHODS: We analyzed our longitudinal, prospective, real-world cohort of 80 cladribine-treated RMS patients from two tertiary centers in Germany. Laboratory testing was conducted monthly and included evaluation of cellular as well as soluble parameters. Laboratory outcomes were correlated with infectious adverse events (AEs) and clinical or paraclinical disease activity. RESULTS: Selective alterations in immune cell populations occurred following cladribine treatment, with the most marked effects observed in year two of treatment. Specifically, a rapid reduction in CD56+ natural killer cells (nadir: month 1 (year 1) and 14 (year 2); -37 and -41% from baseline) was followed by a greater reduction in CD19+ B cells (nadir: month 2 and 14; -81 and -82%); a moderate effect on CD4+ (nadir: month 3 and 15; -48 and -61%) and CD8+ T cells (nadir: month 5 and 18; -40 and -48%). Despite the marked effect on B cells, immunoglobulin levels were unaffected. There was no or minimal effect on thrombocytes and innate immune cells. Clinical and paraclinical disease activity was unrelated to the observed immune alterations. Lymphopenia was the most commonly observed AE (86.3% of patients; grade III-IV lymphopenia: 38.8%). The cumulative incidence of infections was 55% with cladribine treatment, which were mostly mild or moderate. In total, 19 herpes infections developed in 8 (10%) cladribine-treated patients; all cases were dermatomal and 94.7% of the herpetic infections occurred during a period of lymphopenia. CONCLUSIONS: The immunophenotyping data obtained in our real-world setting are comparable to those demonstrated in pivotal clinical trials and provide further evidence that cladribine may represent a form of IRT. However, regarding the side-effect profile of cladribine, severe lymphopenia (exceeding grade II CTCAE) was more frequent, which may have prompted the development of herpes infections. Of note, lymphocyte dynamics did not correlate with clinical and paraclinical measures of disease activity in the two-year follow-up period.

Alemtuzumab-induced immune phenotype and repertoire changes: implications for secondary autoimmunity.

Alemtuzumab is a monoclonal antibody that causes rapid depletion of CD52-expressing immune cells. It has proven to be highly efficacious in active relapsing-remitting multiple sclerosis; however, the high risk of secondary autoimmune disorders has greatly complicated its use. Thus, deeper insight into the pathophysiology of secondary autoimmunity and potential biomarkers is urgently needed. The most critical time points in the decision-making process for alemtuzumab therapy are before or at Month 12, where the ability to identify secondary autoimmunity risk would be instrumental. Therefore, we investigated components of blood and CSF of up to 106 multiple sclerosis patients before and after alemtuzumab treatment focusing on those critical time points. Consistent with previous reports, deep flow cytometric immune-cell profiling (n = 30) demonstrated major effects on adaptive rather than innate immunity, which favoured regulatory immune cell subsets within the repopulation. The longitudinally studied CSF compartment (n = 18) mainly mirrored the immunological effects observed in the periphery. Alemtuzumab-induced changes including increased numbers of naïve CD4+ T cells and B cells as well as a clonal renewal of CD4+ T- and B-cell repertoires were partly reminiscent of haematopoietic stem cell transplantation; in contrast, thymopoiesis was reduced and clonal renewal of T-cell repertoires after alemtuzumab was incomplete. Stratification for secondary autoimmunity did not show clear immununological cellular or proteomic traits or signatures associated with secondary autoimmunity. However, a restricted T-cell repertoire with hyperexpanded T-cell clones at baseline, which persisted and demonstrated further expansion at Month 12 by homeostatic proliferation, identified patients developing secondary autoimmune disorders (n = 7 without secondary autoimmunity versus n = 5 with secondary autoimmunity). Those processes were followed by an expansion of memory B-cell clones irrespective of persistence, which we detected shortly after the diagnosis of secondary autoimmune disease. In conclusion, our data demonstrate that (i) peripheral immunological alterations following alemtuzumab are mirrored by longitudinal changes in the CSF; (ii) incomplete T-cell repertoire renewal and reduced thymopoiesis contribute to a proautoimmune state after alemtuzumab; (iii) proteomics and surface immunological phenotyping do not identify patients at risk for secondary autoimmune disorders; (iv) homeostatic proliferation with disparate dynamics of clonal T- and B-cell expansions are associated with secondary autoimmunity; and (v) hyperexpanded T-cell clones at baseline and Month 12 may be used as a biomarker for the risk of alemtuzumab-induced autoimmunity.

A national, multi-center study in Germany to assess implementation of infusion management, treatment satisfaction and quality of life in MS patients receiving alemtuzumab.

BACKGROUND: Alemtuzumab is an anti-CD52 antibody approved for the treatment of relapsing remitting multiple sclerosis (RRMS). The summary of product characteristics (SmPC) provides recommendations on the administration of alemtuzumab to prevent or reduce the risk of serious side effects associated with alemtuzumab infusion, including myocardial ischemia, hemorrhagic stroke, arterial dissection, and pulmonary alveolar hemorrhage. However, real-world implementation of alemtuzumab infusion management recommendations has not been previously assessed. METHODS: Here we provide a large-scale multi-center (in- and outpatient) observational study on alemtuzumab infusion management in daily clinical care in Germany (ALEMLL08025; INFUSE-MS; NIS-no. 364). Parameters of infusion management - including infusion administration, clinical and laboratory monitoring - were assessed, compared between study centers and the occurrence of infusion-associated reactions (IARs) was documented. Moreover, the TSQM and MSIS-29 questionnaires were used to quantify patient satisfaction and health-related quality of life. RESULTS: 140 RRMS patients were enrolled in this study. Alemtuzumab infusion regimes (treatment course 1 and 2) were comparable between infusion sites and in accordance with recommendations by the SmPC. Standardization of infusion management was associated with a satisfactory safety profile. IARs were usually mild, headache (13.6%), rash (10.7%), and pyrexia (6.4%) being the most common ones. TSQM and MSIS-29 scores denoted high patient satisfaction and health-related quality of life among RRMS patients treated with alemtuzumab. CONCLUSION: In conclusion, our results indicate that infusion management of alemtuzumab is highly standardized and in line with the SmPC. Alemtuzumab treatment and implementation of infusion management recommendations are associated with a satisfactory safety profile regarding the occurrence of IARs, a high patient satisfaction and health-related quality of life as important indicators for the quality of MS care.

Neurological update: treatment escalation in multiple sclerosis patients refractory to fingolimod-potentials and risks of subsequent highly active agents.

A critical issue in the management of relapsing MS (RMS) is the discontinuation of disease-modifying treatments (DMT) due to lack of efficacy, intolerability or impending risks. With new therapeutic agents introduced into the treatment of RMS, immediate- and long-term consequences of sequential drug use, as well as the effect of the sequence in which the drugs are given, are unclear but may affect efficacy, adverse events, and long-term immunocompetence. In the absence of clinical studies specifically addressing these concerns, observations from clinical practice are of particular value in guiding current management algorithms. Prompted by a study published by Ferraro et al. in this journal, we set out to provide an overview of the published real-world evidence on the effectiveness and safety of switching from fingolimod to another DMT in patients with active RMS. Seventeen publications reporting relevant information were identified. The literature suggests that immune cell depletion induced by alemtuzumab or ocrelizumab is associated with an increased risk of relapse and worsening disability in patients switching from fingolimod compared to patients switching from other therapeutic agents. However, the evidence reported for natalizumab and cladribine is inconclusive. While shortening of the washout period may limit early disease reactivation after fingolimod discontinuation, there is no strong evidence that the duration of the washout period or the absolute lymphocyte count at baseline are predictors of attenuated long-term efficacy. Further real-world studies are required to better understand outcomes among patients who are under-represented in controlled trials.

Effectiveness and safety of cladribine in MS: Real-world experience from two tertiary centres.

BACKGROUND: Oral cladribine has been approved for the treatment of relapsing multiple sclerosis (MS) yet real-world evidence regarding its effectiveness and safety remains scarce. OBJECTIVE: To evaluate efficacy and safety outcomes of MS patients following induction of cladribine. METHODS: We evaluated our prospective cohort of cladribine-treated MS patients from two tertiary centres in Germany. Relapses, disability worsening and occurrence of new or enlarging T2-hyperintense magnetic resonance imaging (MRI) lesions were assessed as well as lymphocyte counts and herpes virus infections. RESULTS: Among 270 patients treated with cladribine, we observed a profound reduction of both relapses and new or enlarging MRI lesions. Treatment appeared more efficacious, especially in patients without previous therapy or following platform substances. Patients switching from natalizumab were prone to re-emerging disease activity. Among patients following dimethyl fumarate pre-treatment, severe lymphopenia was common and associated with increased rates of herpes virus manifestations. CONCLUSION: Overall, we observed an efficacy and safety profile of cladribine consistent with data from the phase 3 clinical trial. However, patients switching from natalizumab experienced suboptimal disease control beyond rebound activity following cessation of natalizumab. Furthermore, dimethyl fumarate pre-treatment was associated with a profound risk of developing severe lymphopenia and subsequent herpes virus infections.

Natural Killer Cells Are Present in Rag1-/- Mice and Promote Tissue Damage During the Acute Phase of Ischemic Stroke.

Rag1-/- mice, lacking functional B and T cells, have been extensively used as an adoptive transfer model to evaluate neuroinflammation in stroke research. However, it remains unknown whether natural killer (NK) cell development and functions are altered in Rag1-/- mice as well. This connection has been rarely discussed in previous studies but might have important implications for data interpretation. In contrast, the NOD-Rag1nullIL2rgnull (NRG) mouse model is devoid of NK cells and might therefore eliminate this potential shortcoming. Here, we compare immune-cell frequencies as well as phenotype and effector functions of NK cells in Rag1-/- and wildtype (WT) mice using flow cytometry and functional in vitro assays. Further, we investigate the effect of Rag1-/- NK cells in the transient middle cerebral artery occlusion (tMCAO) model using antibody-mediated depletion of NK cells and adoptive transfer to NRG mice in vivo. NK cells in Rag1-/- were comparable in number and function to those in WT mice. Rag1-/- mice treated with an anti-NK1.1 antibody developed significantly smaller infarctions and improved behavioral scores. Correspondingly, NRG mice supplemented with NK cells were more susceptible to tMCAO, developing infarctions and neurological deficits similar to Rag1-/- controls. Our results indicate that NK cells from Rag1-/- mice are fully functional and should therefore be considered in the interpretation of immune-cell transfer models in experimental stroke. Fortunately, we identified the NRG mice, as a potentially better-suited transfer model to characterize individual cell subset-mediated neuroinflammation in stroke.

K2P18.1 translates T cell receptor signals into thymic regulatory T cell development.

It remains largely unclear how thymocytes translate relative differences in T cell receptor (TCR) signal strength into distinct developmental programs that drive the cell fate decisions towards conventional (Tconv) or regulatory T cells (Treg). Following TCR activation, intracellular calcium (Ca2+) is the most important second messenger, for which the potassium channel K2P18.1 is a relevant regulator. Here, we identify K2P18.1 as a central translator of the TCR signal into the thymus-derived Treg (tTreg) selection process. TCR signal was coupled to NF-κB-mediated K2P18.1 upregulation in tTreg progenitors. K2P18.1 provided the driving force for sustained Ca2+ influx that facilitated NF-κB- and NFAT-dependent expression of FoxP3, the master transcription factor for Treg development and function. Loss of K2P18.1 ion-current function induced a mild lymphoproliferative phenotype in mice, with reduced Treg numbers that led to aggravated experimental autoimmune encephalomyelitis, while a gain-of-function mutation in K2P18.1 resulted in increased Treg numbers in mice. Our findings in human thymus, recent thymic emigrants and multiple sclerosis patients with a dominant-negative missense K2P18.1 variant that is associated with poor clinical outcomes indicate that K2P18.1 also plays a role in human Treg development. Pharmacological modulation of K2P18.1 specifically modulated Treg numbers in vitro and in vivo. Finally, we identified nitroxoline as a K2P18.1 activator that led to rapid and reversible Treg increase in patients with urinary tract infections. Conclusively, our findings reveal how K2P18.1 translates TCR signals into thymic T cell fate decisions and Treg development, and provide a basis for the therapeutic utilization of Treg in several human disorders.

Evaluation of Age-Dependent Immune Signatures in Patients With Multiple Sclerosis.

BACKGROUND AND OBJECTIVES: In MS, an age-related decline in disease activity and a decreased efficacy of disease-modifying treatment have been linked to immunosenescence, a state of cellular dysfunction associated with chronic inflammation. METHODS: To evaluate age-related immunologic alterations in MS, we compared immune signatures in peripheral blood (PB) and CSF by flow cytometry in patients with relapsing-remitting (RR) (PB n = 38; CSF n = 51) and primary progressive (PP) MS (PB n = 40; CSF n = 36) and respective controls (PB n = 40; CSF n = 85). RESULTS: Analysis revealed significant age-related changes in blood immune cell composition, especially in the CD8 T-cell compartment of healthy donors (HDs) and patients with MS. However, HDs displayed a strong age-dependent decline in the expression of the immunoregulatory molecules KLRG1, LAG3, and CTLA-4 on memory CD8 T cells, whereas this age-dependent reduction was completely abrogated in patients with MS. An age-dependent increase in the expression of the costimulatory molecule CD226 on memory CD8 T cells was absent in patients with MS. CD226 expression correlated with disability in younger (≤50 years) patients with MS. CSF analysis revealed a significant age-dependent decline in various immune cell populations in PPMS but not RRMS, suggesting a differential effect of aging on the intrathecal compartment in PPMS. DISCUSSION: Our data illustrate that aging in MS is associated with a dysbalance between costimulatory and immunoregulatory signals provided by CD8 T cells favoring a proinflammatory phenotype and, more importantly, a pattern of premature immune aging in the CD8 T-cell compartment of young patients with MS with potential implications for disease severity.

Amyotrophic lateral sclerosis patients show increased peripheral and intrathecal T-cell activation.

Several studies suggest a role for the peripheral immune system in the pathophysiology of amyotrophic lateral sclerosis. However, comprehensive studies investigating the intrathecal immune system in amyotrophic lateral sclerosis are rare. To elucidate whether compartment-specific inflammation contributes to amyotrophic lateral sclerosis pathophysiology, we here investigated intrathecal and peripheral immune profiles in amyotrophic lateral sclerosis patients and compared them with controls free of neurological disorders (controls) and patients with dementia or primary progressive multiple sclerosis. Routine CSF parameters were examined in 308 patients, including 132 amyotrophic lateral sclerosis patients. In a subgroup of 41 amyotrophic lateral sclerosis patients, extensive flow-cytometric immune cell profiling in peripheral blood and CSF was performed and compared with data from 26 controls, 25 dementia and 21 multiple sclerosis patients. Amyotrophic lateral sclerosis patients presented with significantly altered proportions of monocyte subsets in peripheral blood and increased frequencies of CD4+ and CD8+ T cells expressing the activation marker HLA-DR in peripheral blood (CD8+) and CSF (CD4+ and CD8+) compared with controls. While dementia and multiple sclerosis patients exhibited a comparable increase in intrathecal CD8+ T-cell activation, CD8+ T-cell activation in the peripheral blood in amyotrophic lateral sclerosis was higher than in multiple sclerosis patients. Furthermore, intrathecal CD4+ T-cell activation in amyotrophic lateral sclerosis surpassed levels in dementia patients. Intrathecal T-cell activation resulted from in situ activation rather than transmigration of activated T cells from the blood. While T-cell activation did not correlate with amyotrophic lateral sclerosis progression, patients with rapid disease progression showed reduced intrathecal levels of immune-regulatory CD56bright natural killer cells. The integration of these parameters into a composite score facilitated the differentiation of amyotrophic lateral sclerosis patients from patients of all other cohorts. To conclude, alterations in peripheral monocyte subsets, as well as increased peripheral and intrathecal activation of CD4+ and CD8+ T cells concomitant with diminished immune regulation by CD56bright natural killer cells, suggest an involvement of these immune cells in amyotrophic lateral sclerosis pathophysiology.

Ocrelizumab Extended Interval Dosing in Multiple Sclerosis in Times of COVID-19.

OBJECTIVE: To evaluate the clinical consequences of extended interval dosing (EID) of ocrelizumab in relapsing-remitting multiple sclerosis (RRMS) during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: In our retrospective, multicenter cohort study, we compared patients with RRMS on EID (defined as ≥4-week delay of dose interval) with a control group on standard interval dosing (SID) at the same period (January to December 2020). RESULTS: Three hundred eighteen patients with RRMS were longitudinally evaluated in 5 German centers. One hundred sixteen patients received ocrelizumab on EID (median delay [interquartile range 8.68 [5.09-13.07] weeks). Three months after the last ocrelizumab infusion, 182 (90.1%) patients following SID and 105 (90.5%) EID patients remained relapse free (p = 0.903). Three-month confirmed progression of disability was observed in 18 SID patients (8.9%) and 11 EID patients (9.5%, p = 0.433). MRI progression was documented in 9 SID patients (4.5%) and 8 EID patients (6.9%) at 3-month follow-up (p = 0.232). Multivariate logistic regression showed no association between treatment regimen and no evidence of disease activity status at follow-up (OR: 1.266 [95% CI: 0.695-2.305]; p = 0.441). Clinical stability was accompanied by persistent peripheral CD19+ B-cell depletion in both groups (SID vs EID: 82.6% vs 83.3%, p = 0.463). Disease activity in our cohort was not associated with CD19+ B-cell repopulation. CONCLUSION: Our data support EID of ocrelizumab as potential risk mitigation strategy in times of the COVID-19 pandemic. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that for patients with RRMS, an EID of at least 4 weeks does not diminish effectiveness of ocrelizumab.