Poursalar Alireza, Astaraki Peyman, Khalaf Amal Khudair, Baharvand Parastoo, Sepahvand Asghar, Fallahi Shirzad, Mahmoudvand Hossein
Department of Medical Parasitology and Mycology, Lorestan University of Medical Sciences, Khorramabad, Iran.
Department of Internal Medicine, School of Medicine, Shahid Rahimi Hospital, Lorestan University of Medical Sciences, Khorramabad, Iran.
BMC Infect Dis. 2025 Jul 1;25(1):834. doi: 10.1186/s12879-025-11200-1.
This study aims to investigate the prevalence, socio-economic characteristics, risk factors, and cytokine profile (IL-6, TNF-α, and IFN-γ) of Toxoplasma gondii among individuals who have attempted suicide and referred to health centers in Lorestan province, Western Iran.
This research is a case-control study involved a sample of 250 patients diagnosed with attempting suicide (AS) and 250 healthy individuals without AS (non-AS), who were referred to healthcare centers in Lorestan province, Iran, from September 2023 to September 2024. A questionnaire was provided to collect demographic information, socio-economic factors, and potential risk factors. To evaluate the seroprevalence of T. gondii infection, ELISA kits were used to detect the anti-Toxoplasma IgG and IgM antibodies. The serum and expression levels of interleukin-6, interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α) among AS and non-AS groups were also assessed by ELISA and Real-time PCR methods.
In the AS group, 98 participants (39.2%) and 8 participants (3.2%) were positive for anti-T. gondii IgG and IgM antibody, respectively. Conversely, in the non-AS group, 55 individuals (22.0%) and 5 individuals (2.0%) were positive for anti-T. gondii IgG and IgM antibody, respectively (p < 0.001). In AS patients, age (p = 0.012, OR = 0.288, CI = 0.109-0.761), educational level (p = 0.024, OR = 0.328, CI = 0.124-0.866), residence (p = 0.018, OR = 0.429, CI = 0.212-0.867), consumption of fast food (p = 0.004, OR = 3.719, CI = 1.538-8.993) and history of suicide (p = 0.020, OR = 2.716, CI = 1.170-6.306) demonstrated a significant predictive effect on seropositivity to T. gondii infection. Whereas, a negative result on the antibody test was associated with a 0.465-fold decrease in the likelihood of suicide (p = 0.038, OR = 0.465, CI = 0.225-0.960). The likelihood of suicide demonstrates a positive correlation with increased concentrations of inflammatory cytokines, specifically IL-6 (p = 0.029, OR = 1.134, CI = 1.833-2.951) and IFN-γ (p = 0.004, OR = 1.998, CI = 1.342-2.919).
Our study revealed that individuals who have attempted suicide exhibited a greater seroprevalence of anti-T. gondii antibodies compared to healthy control subjects. We also exhibited elevated serum and expression levels of IL-6 and IFN-γ, as the main proinflammatory cytokines linked to suicide behaviors, in the AS patients who tested positive for T. gondii antibodies. Consequently, this may aid in the identification of biomarkers that could inform the development of effective prevention strategies and ultimately reduce suicide mortality. The findings of the study indicate that while there may be a causal link between T. gondii infection and suicide attempts, the cross-sectional nature of the data may restrict the ability to draw definitive causal inferences. To substantiate this potential causal relationship, longitudinal studies that incorporate larger sample sizes, investigate additional biomarkers related to suicide, and control for various confounding variables would be beneficial.
本研究旨在调查伊朗西部洛雷斯坦省自杀未遂并前往健康中心就诊的个体中弓形虫的患病率、社会经济特征、危险因素及细胞因子谱（白细胞介素-6、肿瘤坏死因子-α和干扰素-γ）。
本研究为病例对照研究，选取了250例被诊断为自杀未遂（AS）的患者和250例无自杀未遂的健康个体（非AS）作为样本，这些个体于2023年9月至2024年9月被转诊至伊朗洛雷斯坦省的医疗中心。通过问卷调查收集人口统计学信息、社会经济因素和潜在危险因素。为评估弓形虫感染的血清阳性率，使用酶联免疫吸附测定（ELISA）试剂盒检测抗弓形虫IgG和IgM抗体。还采用ELISA和实时荧光定量聚合酶链反应（Real-time PCR）方法评估AS组和非AS组中白细胞介素-6、干扰素-γ（IFN-γ）和肿瘤坏死因子-α（TNF-α）的血清水平和表达水平。
在AS组中，分别有98名参与者（39.2%）和8名参与者（3.2%）抗弓形虫IgG和IgM抗体呈阳性。相反，在非AS组中，分别有55名个体（22.0%）和5名个体（2.0%）抗弓形虫IgG和IgM抗体呈阳性（p<0.001）。在AS患者中，年龄（p=0.012，比值比[OR]=0.288，可信区间[CI]=0.109 - 0.761）、教育水平（p=0.024，OR=0.328，CI=0.124 - 0.866）、居住情况（p=0.018，OR=0.429，CI=0.212 - 0.867）、快餐消费（p=0.004，OR=3.719，CI=1.538 - 8.993）和自杀史（p=0.020，OR=2.716，CI=1.170 - 6.306）对弓形虫感染血清阳性具有显著预测作用。而抗体检测结果为阴性与自杀可能性降低0.465倍相关（p=0.038，OR=0.465，CI=0.225 - 0.96）。自杀可能性与炎症细胞因子浓度升高呈正相关，尤其是白细胞介素-6（p=0.029，OR=1.134，CI=1.833 - 2.951）和干扰素-γ（p=0.004，OR=1.998，CI=1.342 - 2.919）。
我们的研究表明，与健康对照者相比，自杀未遂个体抗弓形虫抗体的血清阳性率更高。我们还发现，在弓形虫抗体检测呈阳性的AS患者中，作为与自杀行为相关的主要促炎细胞因子，白细胞介素-6和干扰素-γ的血清水平和表达水平升高。因此，这可能有助于识别生物标志物，为制定有效的预防策略提供依据，并最终降低自杀死亡率。研究结果表明，虽然弓形虫感染与自杀未遂之间可能存在因果关系，但数据的横断面性质可能限制得出明确因果推断结论的能力。为证实这种潜在的因果关系，纳入更大样本量、研究与自杀相关的其他生物标志物并控制各种混杂变量的纵向研究将是有益的。
