Abstract：
Seronegative human immunodeficiency virus (HIV) infection, where an HIV-specific antibody response is lacking even in chronic or late-stage HIV infections, is extremely rare. Here, we report the case of a 50-year-old Japanese man presenting with Pneumocystis pneumonia who did not produce antibodies against HIV-1 until the initiation of antiretroviral therapy (ART). Fourth-generation antigen-antibody testing temporarily reverted from weakly positive to negative soon after initiating ART, likely due to a reduction in viral load (assessed by p24 antigen levels). His HIV-1 antibody titers remained low or indeterminate even after four years of ART. A literature review suggested that the absence of HIV-1-specific antibody production may be associated with unimpeded HIV replication and rapid CD4+ T cell decline. Seronegative HIV infection can lead to deferred diagnosis and treatment, thereby increasing the risk of transmitting the virus to others or developing opportunistic illnesses. It is important to combine multiple tests for diagnosis, depending on the medical condition. Further studies are required to investigate the host factors involved in the production of HIV-1-specific antibodies.
摘要：
血清阴性人类免疫缺陷病毒（HIV）感染，即使在慢性或晚期HIV感染中也缺乏HIV特异性抗体反应，极为罕见。这里,我们报道了一例50岁的日本人出现肺孢子虫肺炎,他在开始抗逆转录病毒治疗(ART)之前没有产生抗HIV-1抗体.开始ART后不久，第四代抗原抗体检测暂时从弱阳性恢复为阴性，可能是由于病毒载量减少（通过p24抗原水平评估）。即使经过四年的ART，他的HIV-1抗体滴度仍然很低或不确定。文献综述表明，缺乏HIV-1特异性抗体的产生可能与HIV不受阻碍的复制和CD4T细胞的快速下降有关。血清阴性HIV感染可导致延迟诊断和治疗，从而增加了将病毒传播给他人或发展为机会性疾病的风险。结合多种测试进行诊断很重要，取决于医疗条件。需要进一步的研究来研究参与HIV-1特异性抗体产生的宿主因素。
