Serum glutamate decarboxylase antibodies and neurological disorders: when to suspect their association?

OBJECTIVES: To explore different neurological manifestations with suspicion of being associated to serum glutamate decarboxylase antibodies (GAD-Abs) in order to better characterize anti-GAD neurological syndromes. METHODS: Observational retrospective study including all patients for whom GAD65-Abs titers in serum were requested by the Neurology Department at La Paz University Hospital between 2015 and 2019. GAD-Abs were measured by ELISA. Demographic data, neurological symptoms, comorbidity with diabetes mellitus (DM) or with another autoimmune disease, and GAD-Abs titers were studied. Stiff-person syndrome, ataxia, encephalitis, and epilepsy were considered typical anti-GAD neurological syndromes and were compared to other atypical manifestations. RESULTS: A total of 173 patients (51.7% men, mean age 51.62) were included. A progressive increase in requests of serum GAD-Abs has occurred over the last 5 years, especially in patients with atypical neurological manifestations. GAD-Abs were found in the serum of 22 patients (12.7%); of those, 15 (68.18%) suffered a typical anti-GAD syndrome. Presence of DM or another organ-specific autoimmune disease was predictive of GAD-AB seropositivity (p < 0.001). 6.6% of requested patients with an atypical syndrome had GAD-Abs, but serum levels were significantly lower than those found in patients with a typical syndrome (706.67 vs 1430.23 UI/mL; Mann-Whitney U, p = 0.034), and were finally diagnosed with another neurological disease. CONCLUSION: Serum GAD-Abs were infrequently found in patients with clinical phenotypes other than those classically described as anti-GAD disorders, and with very low titers. In typical anti-GAD syndromes, there is a high comorbidity with DM and with other autoimmune diseases, and high serum GAD-Abs levels are usually present.

Risk and outcomes of COVID-19 in patients with multiple sclerosis.

BACKGROUND AND PURPOSE: Limited information is available on incidence and outcomes of COVID-19 in patients with multiple sclerosis (MS). This study investigated the risks of SARS-CoV-2 infection and COVID-19-related outcomes in patients with MS, and compared these with the general population. METHODS: A regional registry was created to collect data on incidence, hospitalization rates, intensive care unit admission, and death in patients with MS and COVID-19. National government outcomes and seroprevalence data were used for comparison. The study was conducted at 14 specialist MS treatment centers in Madrid, Spain, between February and May 2020. RESULTS: Two-hundred nineteen patients were included in the registry, 51 of whom were hospitalized with COVID-19. The mean age ± standard deviation was 45.3 ± 12.4 years, and the mean duration of MS was 11.9 ± 8.9 years. The infection incidence rate was lower in patients with MS than the general population (adjusted incidence rate ratio = 0.78, 95% confidence interval [CI] = 0.70-0.80), but hospitalization rates were higher (relative risk = 5.03, 95% CI = 3.76-6.62). Disease severity was generally low, with only one admission to an intensive care unit and five deaths. Males with MS had higher incidence rates and risk of hospitalization than females. No association was found between the use of any disease-modifying treatment and hospitalization risk. CONCLUSIONS: Patients with MS do not appear to have greater risks of SARS-CoV-2 infection or severe COVID-19 outcomes compared with the general population. The decision to start or continue disease-modifying treatment should be based on a careful risk-benefit assessment.