Seronegative HIV-1 infection in a Japanese man presenting with Pneumocystis pneumonia: Analysis of long-term antibody response and literature review.

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.

A Case of Esophageal Cancer With Markedly Elevated Soluble Interleukin-2 Receptor: A Potential of Soluble Interleukin-2 Receptor as a Biomarker.

We report an autopsy case of advanced esophageal cancer with multiple metastases that presented with a markedly high level of sIL-2R. An 83-year-old man was admitted to our hospital with a 1-week history of epigastric distress, appetite loss, and fatigue. Imaging examinations revealed a large liver tumor. Although the tumor markers for gastrointestinal and liver cancers were within normal limits, the sIL-2R level was extremely high (10,384 U/mL). The patient died immediately after admission due to the rapid course of the disease. An autopsy showed advanced esophageal cancer with multiple metastases, including the liver, lungs, and multiple lymph nodes. In histological examinations, esophageal cancer was a mixture of well- and poorly differentiated squamous cell carcinoma, in which poorly differentiated cancer cells expressed sIL-2R on immunohistochemical staining. However, we failed to detect positive staining for sIL-2R in the lymphocytes. Our findings revealed that solid tumors could express sIL-2R. Although sIL-2R is a tumor marker used for hematological malignancies, such as malignant lymphoma, this case report highlights the value of the measurement of sIL-2R levels in advanced solid tumors, including esophageal cancer. We concluded that sIL-2R has potential as a biomarker in advanced solid tumors for cancer staging and treatment response.

Draft genome sequence of Nocardia sp. strain JMUB6875 isolated from a patient with disseminated nocardiosis.

We report the draft genome sequence of the Nocardia sp. strain JMUB6875, isolated from a blood culture specimen of a patient with disseminated nocardiosis. This strain appears to be a potentially novel species closely related to Nocardia concava.

A case of Wernicke encephalopathy arising in the early stage after the start of hemodialysis.

Wernicke encephalopathy (WE) resulting from vitamin B1 (VB1) deficiency is commonly regarded as being associated with a high alcohol intake; however, recently many non-alcohol-related cases have been reported. Herein, we report a case of WE due to VB1 deficiency in the early stage after the start of hemodialysis. The patient was a 79-year-old male recommended for hemodialysis due to chronic renal failure. He was admitted to our hospital due to a hemorrhagic duodenal ulcer, but hemodialysis was started as the result of exacerbation of renal function. After the start of 3-times-weekly hemodialysis, the patient's general condition was settled and he was able to consume about half his usual dietary intake. Seventeen days after the start of hemodialysis, impaired consciousness and involuntary movements appeared, and subsequent head magnetic resonance imaging showed increased signal intensity around the cerebral aqueduct. VB1 administration based on a suspicion of WE resulted in a significant improvement in neurological symptoms and no sequelae were observed. Hemodialysis may be a risk factor for VB1 deficiency. When a dialysis patient presents with psychiatric symptoms or impaired consciousness, in particular, it is important to always keep the possibility of VB1 deficiency in mind.