Incidence and Epidemiology of Citrus Viroids in Greece: Role of Host and Cultivar in Epidemiological Characteristics.

Viroids represent a threat to the citrus industry and also display an intricate matter for citrus tristeza virus (CTV) control as most of the commercial citrus rootstocks that are resistant/tolerant to CTV appear to be highly susceptible to viroid infection. Therefore, a detailed knowledge of the viroid's incidence and distribution, along with the assessment of unexplored epidemiological factors leading to their occurrence, are necessary to further improve control measures. Herein, a large-scale epidemiological study of citrus viroids in five districts, 38 locations and 145 fields in Greece is presented, based on the analysis of 3005 samples collected from 29 cultivars of six citrus species. We monitored the occurrence of citrus exocortis (CEVd), hop stunt (HSVd), citrus dwarfing (CDVd), citrus bark cracking (CBCVd), and citrus bent leaf (CBLVd) viroids, and addressed their epidemiological patterns and factors shaping their population structure. Our results show a high frequency and wide distribution of four viroids in all areas and in almost all hosts, whereas CBLVd occurrence was restricted to Crete. Mixed infections were found in all districts in which a wide spread of viroids was observed. We identified a potential pathogens' different preferences that could be partially explained by the host and cultivar, including the type of infection (single or mixed) and the number of viroids in the mixed infections. Overall, this work provides the first detailed epidemiological study on citrus viroids, enriching our knowledge for the implementation, production, and distribution of certified citrus propagative material, and the development of sustainable control strategies.

Antigen-specific immunoadsorption of MuSK autoantibodies as a treatment of MuSK-induced experimental autoimmune myasthenia gravis.

Myasthenia gravis (MG) is an autoimmune disease affecting the neuromuscular junction. Approximately 9% of MG patients have autoantibodies targeting the muscle specific kinase (MuSK), and are challenging therapeutically, since they often present with more severe symptoms. A useful therapy is plasmapheresis, but it is highly non-specific. Antigen-specific immunoadsorption would only remove the pathogenic autoantibodies, minimizing the possible side effects and maximizing the benefit. We used rats with human MuSK-induced experimental autoimmune MG to perform antigen-specific immunoadsorptions, and found it very effective, resulting in a dramatic autoantibody titer decrease, while immunoadsorbed, but not mock-treated, animals showed an significant improvement of their clinical symptoms. Overall, the procedure was efficient, supporting its application for MG treatment.