Identification of disease phenotypes in acetylcholine receptor-antibody myasthenia gravis using proteomics-based consensus clustering.

BACKGROUND: The clinical heterogeneity of myasthenia gravis (MG), an autoimmune disease defined by antibodies (Ab) directed against the postsynaptic membrane, constitutes a challenge for patient stratification and treatment decision making. Novel strategies are needed to classify patients based on their biological phenotypes aiming to improve patient selection and treatment outcomes. METHODS: For this purpose, we assessed the serum proteome of a cohort of 140 patients with anti-acetylcholine receptor-Ab-positive MG and utilised consensus clustering as an unsupervised tool to assign patients to biological profiles. For in-depth analysis, we used immunogenomic sequencing to study the B cell repertoire of a subgroup of patients and an in vitro assay using primary human muscle cells to interrogate serum-induced complement formation. FINDINGS: This strategy identified four distinct patient phenotypes based on their proteomic patterns in their serum. Notably, one patient phenotype, here named PS3, was characterised by high disease severity and complement activation as defining features. Assessing a subgroup of patients, hyperexpanded antibody clones were present in the B cell repertoire of the PS3 group and effectively activated complement as compared to other patients. In line with their disease phenotype, PS3 patients were more likely to benefit from complement-inhibiting therapies. These findings were validated in a prospective cohort of 18 patients using a cell-based assay. INTERPRETATION: Collectively, this study suggests proteomics-based clustering as a gateway to assign patients to a biological signature likely to benefit from complement inhibition and provides a stratification strategy for clinical practice. FUNDING: CN and CBS were supported by the Forschungskommission of the Medical Faculty of the Heinrich Heine University Düsseldorf. CN was supported by the Else Kröner-Fresenius-Stiftung (EKEA.38). CBS was supported by the Deutsche Forschungsgemeinschaft (DFG-German Research Foundation) with a Walter Benjamin fellowship (project 539363086). The project was supported by the Ministry of Culture and Science of North Rhine-Westphalia (MODS, "Profilbildung 2020" [grant no. PROFILNRW-2020-107-A]).

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.

Can lansoprazole, amoxicillin, and clarithromycin combination still be used as a first-line therapy for eradication of helicobacter pylori?

BACKGROUND/AIMS: To determine H. pylori eradication rate with lansoprazole-amoxicillin-clarithromycin treatment regimen, which is the most frequently used as first-line therapy, in the Kirikkale region. METHODS: One hundred and five patients (44 male, 61 female) with H. pylori infection were included in the study. Patients were divided into two groups based on the endoscopic findings: non-ulcer dyspepsia (n=84, 31 male, 53 female) and acute gastric or duodenal ulcer (n=21, 13 male, 8 female) groups. The diagnosis of H. pylori infection was confirmed if both the urease test and histological examination, which were performed on endoscopic biopsies, were positive. Lansoprazole 30 mg, amoxicillin 1 g, and clarithromycin 500 mg were given twice daily for 14 days to all patients. Endoscopic biopsies were repeated for the evaluation of eradication three months after the treatment. RESULTS: Ninety-six patients completed the study. Eradication rates were found to be 45.8% (44 of 96) in all patients, 42.1% (32 of 76 patients) in the non-ulcer dyspepsia group and 60% (12 of 20 patients) in the gastric or duodenal ulcer group for per protocol analysis, and the difference between non-ulcer dyspepsia and gastric or duodenal ulcer groups was not statistically significant (p=0.208). CONCLUSIONS: Lansoprazole-amoxicillin-clarithromycin treatment regimen, the most frequently preferred regimen in H. pylori eradication, is ineffective in our region. The low eradication rates observed with lansoprazole-amoxicillin-clarithromycin, at least in our region, bring into question its use as a first-line therapy. The use of alternative treatment protocols or antibiotic susceptibility test before the treatment may be helpful in achieving successful eradication with first-line therapy.