Anti-Ma2 antibody encephalitis associated with Sjogren's syndrome

Onconeuronal antibodies directed against intracellular antigens are strongly associated with paraneoplastic syndromes and their detection in the absence of cancer is unusual. We herein report a case of anti-Ma2 encephalitis associated with Sjogren's syndrome (SS).

An 81-year-old woman followed for a cutaneous lupus with vasculitis associated with SS presented a flare of her disease with neurological worsening including walking difficulty, hypersialorrhea and dysphagia. A paraneoplastic origin of the symptoms was suspected and anti-Ma2 antibodies were positive in serum. The search for an underlying neoplasia was negative. The diagnosis of anti-Ma2 encephalitis secondary to a SS was made. In the literature, the association of anti-Ma2 encephalitis and SS has been previously reported twice. Cases of patients with other onconeuronal antibodies associated with SS have been also reported. Anti-Ma2 encephalitis is a rare condition with a wide spectrum of symptoms associated with a cancer in more than 90% of the cases. Anti-Ma2 encephalitis has also been described after the use of immune check points inhibitors underscoring the role of autoimmunity in its pathogenesis.

Anti-Ma2 encephalitis is essentially associated with neoplasia but can occur in Sjogren's syndrome.