抗アクアポリン4抗体陽性視神経炎にサトラリズマブを導入後，1年以上再発のない2症例

Two cases of anti-aquaporin 4 antibody-positive optic neuritis without recurrence for more than 1 year after introduction of satralizumab

要約　目的：抗アクアポリン4（AQP4）抗体陽性視神経炎における再発予防薬として，抗IL-6受容体抗体薬（サトラリズマブ）が近年使用可能となった。今回，サトラリズマブ導入後に1年以上再発なく経過した2症例を経験したため報告する。

症例1：58歳，女性。主訴は左眼視力低下と頭痛。既往歴に統合失調症と右眼視神経炎に対するステロイドパルス治療歴を認めた。初診時矯正視力は右0.6，左0.02，限界フリッカ値は右19Hz，左5Hzと，左眼で著明な低下を認めた。頭部CT検査で左視神経の腫大を認め，採血検査で血清抗AQP4抗体陽性であった。ステロイドパルスを1クール施行し，左眼矯正視力は1.2に改善した。プレドニゾロン漸減および再発予防のためサトラリズマブを導入し，1年以上再発なく経過した。

症例2：60歳，女性。主訴は左眼眼球運動痛と視力低下。初診時視力は右1.2，左手動弁で，左眼はRAPD陽性であった。造影MRI検査において左眼窩尖部で左視神経の腫大および増強効果を認め，採血検査では血清抗AQP4抗体陽性であった。ステロイドパルスを1クール施行したが，視力の改善に乏しく，脳神経内科併診のうえステロイドパルスおよび血漿交換療法を6回施行し，左眼矯正視力は1.2に改善した。その後サトラリズマブを導入し，1年以上再発なく経過した。

結論：抗AQP4抗体陽性視神経炎症例に対する再発予防として，サトラリズマブは投与を検討すべき薬剤と考えられた。

Abstract　Purpose：Anti-IL-6 receptor antibody drug（satralizumab） has recently become available for the prevention of recurrence in patients with anti-aquaporin-4 antibody-positive optic neuritis. Here, we report two cases of anti-aquaporin 4 antibody-positive optic neuritis without recurrence for more than 1 year after introduction of satralizumab.

Case 1：58-year-old female. Chief complaint was vision loss in her left eye and headache. History of schizophrenia and steroid pulse therapy for optic neuritis in the right eye were noted. Her best corrected visual acuity was 0.6 in the right eye and 0.02 in the left eye, and the central flicker value was 19 Hz in the right eye and 5 Hz in the left eye at the initial examination. A CT scan of the head showed an enlarged left optic nerve, and a blood sample was positive for serum anti-aquaporin 4 antibody. After one course of steroid pulse therapy, visual acuity in the left eye improved to 1.2, and satralizumab was introduced to decrease PSL and to prevent recurrence, and the patient has remained relapse-free for more than one year.

Case 2：A 60-year-old woman. Chief complaint was oculomotor pain and vision loss in the left eye. Her best corrected visual acuity was 1.2 in the right eye, hand motion in her left eye, and positive for RAPD in the left eye at the initial examination. Contrast-enhanced MRI showed left optic nerve swelling and enhancement at the left orbital apex, and a blood sample was positive for serum anti-aquaporin 4 antibody. After one course of steroid pulse therapy, his visual acuity did not improve. After a concurrent medical examination, he underwent steroid pulse more 2 times and plasma exchange therapy five times, and his visual acuity in the left eye improved to 1.2. Satralizumab was subsequently introduced, and the patient had no recurrence for more than one year.

Conclusion：Satralizumab should be considered for prevention of relapse in patients with anti-aquaporin 4 antibody-positive optic neuritis.