抗GABABR抗体和抗KCTD16抗体双阳性自身免疫性脑炎(附1例报告及文献复习)

目的提高和拓展对抗γ-氨基丁酸B型受体(GABABR)抗体和抗钾离子通道四聚体结构域蛋白16(KCTD16)抗体双阳性自身免疫性脑炎的认识。方法收集1例抗GABABR抗体和抗KCTD16抗体双阳性的自身免疫性脑炎患者的临床资料,总结诊断、治疗经过等临床特点,结合文献复习进行分析和讨论。结果患者男性,50岁,亚急性起病,表现为精神行为异常、记忆障碍和癫痫发作。脑脊液蛋白增高(1.10g·L^-1),细胞数正常,血清和脑脊液抗GABABR抗体阳性。头颅磁共振检查示双侧海马信号增高。诊断为抗GABABR脑炎。对糖皮质激素、静脉注射免疫球蛋白、血浆置换治疗反应良好,但经历多次复发。随访过程中,患者血清中检测到抗KCTD16抗体阳性。发病1年后,患者全身正电子发射计算机断层显像示右肺近肺门软组织结节,远端阻塞性炎症,氟代脱氧葡萄糖代谢异常增高,行肺结节穿刺未见异形细胞,支气管镜未见出血及新生物。后续随访患者肺部结节进一步增大,最终病理活检证明为小细胞肺癌。结论抗KCTD16抗体可存在于抗GABAbR脑炎患者中,且与小细胞肺癌密切相关。

A Male Autoimmune Encephalitis with GABABR and KCTD16 Antibodies:A Case Report and Literature Review

Aim To report a male autoimmune encephalitis with γ-aminobutyric acid type B receptor(GABAbR)and potassium channel tetramerization domain-containing 16(KCTD16)antibodies.Methods The clinical and nearly one-year follow-up data of one male autoimmune encephalitis with GABAbR and KCTD16 antibodies were retrospectively collected.The process of diagnosis and response to the treatment combined with some literature were analyzed.Results IThe patient was a middle-age male presenting with subacute onset of behavior change,memory impairment and seizures.Anti-GABABR antibody was detected in both serum and cerebrospinal fluid(CSF).CSF findings showed an elevated protein level with a normal cell count.MRI Flair imaging showed bilateral hippocampus hyperintensity.The patient responded well to immunotherapy even though underwent several relapses.One year after disease onset,a whole-body PET-CT demonstrated a nodule near the hilar of the right lung with abnormally increased FDG uptake highly suggesting malignancy,but the biopsy and tracheobronchoscopy were clear.Anti KCTD16 antibody was identified in the patient’s serum and he eventually had pathologically-confirmed small cell lung cancer during the subsequent follow up.Conclusion The co-occurrence of KCTD16 antibodies can be identified in patient with anti GABAbR encephalitis and indicating a paraneoplastic origin,especially in a small cell lung cancer.