Rho GTPase-activating protein 10 (ARHGAP10/GRAF2) is a novel autoantibody target in patients with autoimmune encephalitis.

BACKGROUND: In 2010, we described a novel immunoglobulin G (IgG) autoantibody (termed anti-Ca after the index case) targeting Rho GTPase-activating protein 26 (ARHGAP26, also termed GTPase regulator associated with focal adhesion kinase [GRAF], or oligophrenin-like protein 1 [OPHN1L]) in autoimmune cerebellar ataxia (ACA). Later, ARHGAP26-IgG/anti-Ca was reported in patients with limbic encephalitis/cognitive decline or peripheral neuropathy. In several of the reported cases, the syndrome was associated with cancer. ARHGAP10/GRAF2, which is expressed throughout the central nervous system, shares significant sequence homology with ARHGAP26/GRAF. Mutations in the ARHGAP10 gene have been linked to cognitive and psychiatric symptoms and schizophrenia. OBJECTIVE: To assess whether ARHGAP26-IgG/anti-Ca co-reacts with ARHGAP10. METHODS: Serological testing for ARHGAP10/GRAF2 autoantibodies by recombinant cell-based assays and isotype and IgG subclass analyses. RESULTS: 26/31 serum samples (84%) from 9/12 (75%) ARHGAP26-IgG/anti-Ca-positive patients and 4/6 ARHGAP26-IgG/anti-Ca-positive CSF samples from four patients were positive also for ARHGAP10-IgG. ARHGAP10-IgG (termed anti-Ca2) remained detectable in the long-term (up to 109 months) and belonged mainly to the complement-activating IgG1 subclass. Median ARHGAP26-IgG/anti-Ca and median ARHGAP10-IgG/anti-Ca2 serum titres were 1:3200 and 1:1000, respectively, with extraordinarily high titres in some samples (ARHGAP26-IgG/anti-Ca: up to 1:1000,000; ARHGAP10-IgG: up to 1:32,000). ARHGAP26/anti-Ca serum titres exceeded those of ARHGAP10-IgG in all samples but one. A subset of patients was positive also for ARHGAP10-IgM and ARHGAP10-IgA. CSF/serum ratios and antibody index calculation suggested intrathecal production of ARHGAP26-IgG/anti-Ca and anti-ARHGAP10. Of 101 control samples, 100 were completely negative for ARHGAP10-IgG; a single control sample bound weakly (1:10) to the ARHGAP10-transfected cells. CONCLUSIONS: We demonstrate that a substantial proportion of patients with ARHGAP26-IgG/anti-Ca-positive autoimmune encephalitis co-react with ARHGAP10. Further studies on the clinical and diagnostic implications of ARHGAP10-IgG/anti-Ca2 seropositivity in patients with autoimmune encephalitis are warranted.

Factors affecting prehospital delay in rural and urban patients with stroke: a prospective survey-based study in Southwest Germany.

BACKGROUND: Reducing prehospital delay plays an important role in increasing the thrombolysis rate in patients with stroke. Several studies have identified predictors for presentation ≤4.5 h, but few compared these predictors in urban and rural communities. We aimed to identify predictors of timely presentation to the hospital and identify possible differences between the urban and rural populations. METHODS: From January to June 2017, we conducted a prospective survey of patients with stroke admitted to an urban comprehensive stroke centre (CSC) and a rural primary care centre (PCC). Predictors were identified using binary logistical regression. Predictors and patient characteristics were then compared between the CSC and PCC. RESULTS: Overall, 459 patients were included in our study. We identified hesitation before seeking help, awareness of the existence of a time-window, type of admission and having talked about stroke symptoms with friends/relatives who had previously had a stroke as the strongest predictors for presentation to the emergency room ≤4.5 h. Patients admitted to the rural PCC were more hesitant to seek help and less likely to contact emergency services, even though patients had comparable knowledge pertaining to stroke care concepts. CONCLUSIONS: Patients from rural areas were more likely to be hesitant to seek help and contacted the EMS less frequently, despite similar self-awareness of having a stroke. Educational campaigns should focus on addressing these disparities in rural populations. Affected patients should also be encouraged to talk about their symptoms and take part in educational campaigns.

Patient profiles contribute to differences in quality metrics of stroke centers.

OBJECTIVE: To examine this association by comparing patient profiles in 2 closely affiliated hospitals and by examining their association with quality metrics. METHODS: We performed a retrospective cohort study comparing a university level comprehensive stroke centers (CSC) with its teaching hospital and local stroke unit (LSU) using routinely collected quality assurance data over a 2 year period. Both hospitals were closely affiliated, shared important resources and medical staff rotated amongst both hospitals. We compared patient profiles as well as internationally recognized quality metrics and examined the association of profiles with quality metrics. RESULTS: A total of 2,462 patients were treated in the CSC and 726 in the LSU. The LSU had a longer door-to-image and door-to-needle times. Rate of systemic thrombolysis was lower in the LSU. Patient profiles differed significantly and were associated with door-to-image and door-to-needle times as well as intravenous thrombolysis rates, even when adjusted for stroke service level. The diagnostic procedures for stroke work-up were similar. Discharge management differed strongly. CONCLUSION: Although LSUs and CSCs are the primary care providers in their respective regions, differences in patient profiles may contribute to differences in performance parameters. Adjusting for patient profiles may improve the comparability of the quality of stroke care provided by hospitals belonging to different stroke service levels.

Caspr2 antibodies in limbic encephalitis with cerebellar ataxia, dyskinesias and myoclonus.

Here we report on a case of contactin-associated protein-2 (Caspr2) antibody positive but voltage gated potassium channel (VGKC) antibody negative limbic encephalitis associated with cerebellar ataxia, myoclonus and dyskinesias with favorable response to immunotherapy. This case underlines the importance of Caspr2-specific antibody testing and demonstrates that Caspr2 antibodies are associated with a broader clinical spectrum than hitherto described.

Two new cases of anti-Ca (anti-ARHGAP26/GRAF) autoantibody-associated cerebellar ataxia.

Recently, we discovered a novel serum and cerebrospinal fluid (CSF) autoantibody (anti-Ca) to Purkinje cells in a patient with autoimmune cerebellar ataxia (ACA) and identified the RhoGTPase-activating protein 26 (ARHGAP26; alternative designations include GTPase regulator associated with focal adhesion kinase pp125, GRAF, and oligophrenin-1-like protein, OPHN1L) as the target antigen. Here, we report on two new cases of ARHGAP26 autoantibody-positive ACA that were first diagnosed after publication of the index case study. While the index patient developed ACA following an episode of respiratory infection with still no evidence for malignancy 52 months after onset, neurological symptoms heralded ovarian cancer in one of the patients described here. Our finding of anti-Ca/anti-ARHGAP26 antibodies in two additional patients supports a role of autoimmunity against ARHGAP26 in the pathogenesis of ACA. Moreover, the finding of ovarian cancer in one of our patients suggests that anti-Ca/anti-ARHGAP26-positive ACA might be of paraneoplastic aetiology in some cases. In conclusion, testing for anti-Ca/anti-ARHGAP26 should be included in the diagnostic work-up of patients with ACA, and an underlying tumour should be considered in patients presenting with anti-Ca/ARHGAP26 antibody-positive ACA.

Adult-onset dystonia: atypical manifestation of Segawa disease.

A 33-year-old woman developed exercise-induced limb and trunk dystonia with marked diurnal fluctuations. Treatment with levodopa improved her symptoms considerably but incompletely. Molecular genetic analysis revealed a mutation in GTP cyclohydrolase 1 (GCH1). This report illustrates the variability of Segawa disease and underlines the importance of a levodopa test in patients with uncommon dystonic symptoms.

Metabolic imaging of atrophic muscle tissue using appropriate markers in 1H and 31P NMR spectroscopy.

INTRODUCTION: The purpose of this feasibility study was to demonstrate non-invasive metabolic imaging of human muscular atrophy using significant changes of NMR signals that are related directly or indirectly to fiber necrosis. METHODS: Single-voxel (1)H NMR spectroscopy and two-dimensional (31)P spectroscopic imaging on a 1.5-T whole-body scanner were used for in vivo mapping of areas of muscle damage in two cases of differently localized and pronounced atrophy. Spectral patterns affiliated with severe and intermediate stages of degeneration were compared to data of healthy control tissue to derive appropriate metabolic markers related to lipid infiltration or high-energy (31)P metabolism. RESULTS: Reliable detection of atrophic tissue was achieved by the following parameters: (1) liposclerotic turnover is related to a drastic reduction in the water/lipid (1)H signal intensity ratio (up to a factor of 74 compared to adjacent healthy tissue); (2) the (31)P resonance of phosphocreatine (PCr) is an adequate marker for differentiation of intact myocells with high-energy metabolism from regions dominated by terminal fiber necrosis (PCr signal vanished nearly completely or intensity was reduced by a factor of 3 in affected muscles). Metabolic images based on this signal allowed accurate non-invasive localization of atrophic tissue. CONCLUSION: The molecular information provided by NMR spectroscopy--previously only used with poor localization in atrophy studies--enables access to both the myocell-specific high-energy metabolism and the result of lipid infiltration allowing non-invasive mapping of degenerate tissue. The ability to investigate the results of these advanced levels of atrophy would also be useful for studies of more subtle degrees of denervation.