Anti-Adenylate Kinase 5 Encephalitis With Histologic Evidence of CNS Vasculitis

Anti-adenylate kinase 5 encephalitis: Clinical characteristics, diagnosis, and management of this rare entity

“…Unlike other typical neuronal cell-surface antibody-associated LE (i.e., anti-LGI1/CASPR2 encephalitis) for which responsible antibodies play pathogenic roles, no evidence of direct involvement of antibodies against AK5 has been demonstrated. Neuropathological analysis from previous studies revealed an expression of intense granzyme B, activated macrophages/microglia, and infiltration of immune cells in the brain parenchyma, predominated with T-cell (CD3 + , CD4 + , CD8 + ) [ 9 , 13 , 18 ], and these results resemble that observed in patients with paraneoplastic neurological syndrome with antibodies against intracellular antigens (e.g., Hu, Ma2, KLHL11), suggesting analogical pathological mechanism that cytotoxic T-cell-mediating immunological response plays a crucial role in the pathogenesis of anti-AK5 encephalitis [ 10 , [19] , [20] , [21] ]. Furthermore, similar to LE with antibodies targeting intracellular antigens, patients with anti-AK5 encephalitis showed poorer response to immunotherapy than those with antibodies targeting neuronal surface antigens (e.g., NMDAR, LGI1, CASPR2), thus also indicating different pathogenic mechanisms between these subtypes [ 10 , 11 , [22] , [23] , [24] , [25] ].…”

“…All relevant articles were retrieved, and their references were searched to identify as many additional studies as possible. Based on 6 case series (29 patients), 2 individual case reports (2 patients), 31 patients with anti-AK5 encephalitis have been identified so far [ 7 , 9 , [11] , [12] , [13] , [14] , [15] ]. Only 1 patient whose critical data was missing was excluded.…”