Significant clinical improvement was observed, and by the 18th day of admission, the patient was stable and coherent. == Conclusions == The current patient represents the first reported case of double-positive autoimmune encephalitis for anti-D2R and DPPX antibodies, with epilepsy as a prominent feature. DPPX antibody-associated autoimmune encephalitis. The patient underwent a comprehensive treatment regimen, including high-dose methylprednisolone pulse therapy combined with intravenous immunoglobulin (IVIG), antiviral and anti-infection treatments, and antiepileptic medications. Significant clinical improvement was observed, and by the 18th day of admission, the patient was stable and coherent. == Conclusions == The current patient represents the first reported case of double-positive autoimmune encephalitis for anti-D2R and DPPX antibodies, with epilepsy as a prominent feature. High-dose methylprednisolone pulse therapy combined with IVIG has shown significant safety and efficacy in treating anti-D2R and DPPX antibody-positive autoimmune encephalitis-associated epilepsy. Keywords:autoimmune encephalitis, anti-D2R antibody, anti-DPPX antibody, epilepsy, methylprednisolone, intravenous immunoglobulin == 1. Introduction == Autoimmune encephalitis is an intricate neurological disorder characterized by inflammation of the brain due to an immune system attack on neuronal cells (1). In clinical practice, the underdiagnosis of autoimmune encephalitis poses a significant challenge. The disease manifests with a diverse WAY-362450 range of symptoms, including cognitive impairment, behavioral abnormalities, motor dysfunction, and seizures, WAY-362450 leading to overlaps with other neurological disorders (2). The lack of specificity in these symptoms makes it susceptible to misdiagnosis during the initial assessment (2,3). Furthermore, the exact etiology and course of autoimmune encephalitis remain incompletely understood, adding to the complexity of its diagnosis. The delay in diagnosis can result in missed opportunities for early intervention, with immunotherapy playing a pivotal role in the management of autoimmune encephalitis (4). Therefore, it is imperative to enhance medical awareness of autoimmune encephalitis, intensify vigilance for early detection, and further improve diagnostic tools and methods in clinical settings. The detection of specific autoantibodies has emerged as a crucial tool in diagnosing autoimmune encephalitis, providing valuable insights into the underlying immunological mechanisms, and guiding targeted therapeutic interventions (5). Identifying autoantibodies associated with autoimmune encephalitis, such as anti-N-methyl-D-aspartate receptor (NMDAR) antibodies and anti-leucine-rich glioma-inactivated 1(LGI1) antibodies, has significantly contributed to refining the diagnostic process. These antibodies serve as specific biomarkers, helping clinicians distinguish autoimmune encephalitis from other neurological conditions with similar clinical presentations. Furthermore, the presence of certain autoantibodies often correlates with distinct clinical phenotypes and outcomes. For instance, the detection WAY-362450 of anti-NMDAR antibodies FLJ42958 is frequently associated with psychiatric symptoms (6), whereas anti-LGI1 antibodies are linked to limbic encephalitis (7). This correlation enhances the specificity of the diagnosis and facilitates personalized treatment strategies tailored to the patients antibody profile. Autoimmune encephalitis associated with anti-dopamine D2 receptor (D2R) and anti-dipeptidyl-peptidase-like protein 6 (DPPX) antibodies is relatively rare (8,9), but it is observed in certain populations, with a higher prevalence in younger individuals (8). Due to the relative rarity of these cases, in-depth studies are needed to improve the diagnosis and treatment of such conditions. In this case report, we present an anti-D2R and DPPX antibody-associated autoimmune encephalitis patient, whose primary clinical manifestation was epilepsy. This case report provides valuable insights for clinicians in the diagnosis of autoimmune encephalitis with coexistence of different antibodies. It helps expand understanding of the subtypes of patients with autoimmune encephalitis. The successful treatment of this patient using a regimen of methylprednisolone and intravenous immunoglobulin offers clinicians an effective therapeutic approach, particularly for those with similar antibody profiles. == 2. Case description == A 53-year-old Han Chinese man was admitted to our emergency department with a 3-day history of fatigue and limb soreness. This was followed by an episode of limb convulsions lasting 4 min5 min, resulting in a loss of consciousness lasting 3 h, accompanied by urinary and fecal incontinence. The patient reported no fever, chills, cough and sputum, chest distress, or shortness of breath. The patients WAY-362450 family noted his generally good health, without previous medical records of internal medicine conditions such WAY-362450 as hypertension, diabetes, heart disease, or kidney disease. Additionally, there was no record of infectious diseases like tuberculosis or hepatitis, major surgeries, injuries, blood transfusions, poisonings, current medications use, substance addiction, or known allergies to medications or foods. The patient has a regular alcohol and smoking habit for over 30 years, but no prolonged exposure to industrial dust, toxic substances, or radioactive materials. Furthermore, known autoimmune diseases, brain viral infections, epilepsy, or related conditions were ruled out. The patient denied.