Since December 2019, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has caused millions of deaths and seriously threatened the safety of human life; indeed, this situation is worsening and many people are infected with the new coronavirus every day. Therefore, it is very important to understand patients\' degree of infection and infection history through antibody testing. Such information is useful also for the government and hospitals to formulate reasonable prevention policies and treatment plans. In this paper, we develop a lateral flow immunoassay (LFIA) method based on superparamagnetic nanoparticles (SMNPs) and a giant magnetoresistance (GMR) sensing system for the simultaneously quantitative detection of anti-SARS-CoV-2 immunoglobulin M (IgM) and G (IgG). A simple and time-effective co-precipitation method was utilized to prepare the SMNPs, which have good dispersibility and magnetic property, with an average diameter of 68 nm. The Internet of Medical Things-supported GMR could transmit medical data to a smartphone through the Bluetooth protocol, making patient information available for medical staff. The proposed GMR system, based on SMNP-supported LFIA, has an outstanding advantage in cost-effectiveness and time-efficiency, and is easy to operate. We believe that the suggested GMR based LFIA system will be very useful for medical staff to analyze and to preserve as a record of infection in COVID-19 patients.

BACKGROUND: The diagnosis of immunoglobulin G serum antibodies to myelin oligodendrocyte glycoprotein (MOG-IgG) associated inflammatory demyelinating disorders can be confirmed by the presence of MOG-IgG, yet its general cut-off concentration had not yet to be defined. Whether it is significant that a seropositive lower titer level for MOG-IgG could cause disease is still unknown.
METHODS: A 55-year-old Chinese woman presented with acute optic neuritis manifestations in the left eye. MRI showed a left optic nerve demyelination image and a T2 hyperintensity at C7 vertebral segment without any extra specific lesions. AQP4-IgG was tested seronegative, while the MOG-IgG was positive, titer 1:10, by indirect immunofluorescence. Considering the lower concentration, we retested serum MOG-IgG after 6 months of steroid therapy, using cell-based assay, then we still got the same result which was also barely above the negative cut-off value. So, the clinical diagnose was \"possible MOG-IgG-associated encephalomyelitis\". The woman\'s condition improved by steroid therapy without relapse.
CONCLUSIONS: Seropositive MOG-IgG, even at a lower level, could lead to an autoimmune inflammatory demyelination. In adults, it commonly presents as ON and myelitis. Although the patient had a considerable reaction, steroid therapy could not make MOG-IgG seronegative, instead, the antibody may persist even during remission and flare-ups can recur after steroid withdrawal. Therefore, a long-term follow-up is necessary to monitor the patient\'s prognosis.

Patients receiving maintenance hemodialysis (MHD) are highly vulnerable to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The current study was designed to evaluate the prevalence of SARS-CoV-2 infection based on both nucleic acid testing (NAT) and antibody testing in Chinese patients receiving MHD.
Cross-sectional study.
From December 1, 2019, to March 31, 2020, a total of 1,027 MHD patients in 5 large hemodialysis centers in Wuhan, China, were enrolled. Patients were screened for SARS-CoV-2 infection by symptoms and initial computed tomography (CT) of the chest. If patients developed symptoms after the initial screening was negative, repeat CT was performed. Patients suspected of being infected with SARS-CoV-2 were tested with 2 consecutive throat swabs for viral RNA. In mid-March 2020, antibody testing for SARS-CoV-2 was obtained for all MHD patients.
NAT and antibody testing results for SARS-CoV-2.
Morbidity, clinical features, and laboratory and radiologic findings.
Differences between groups were examined using t test or Mann-Whitney U test, comparing those not infected with those infected and comparing those with infection detected using NAT with those with infection detected by positive serology test results.
Among 1,027 patients receiving MHD, 99 were identified as having SARS-CoV-2 infection, for a prevalence of 9.6%. Among the 99 cases, 52 (53%) were initially diagnosed with SARS-CoV-2 infection by positive NAT; 47 (47%) were identified later by positive immunoglobulin G (IgG) or IgM antibodies against SARS-CoV-2. There was a spectrum of antibody profiles in these 47 patients: IgM antibodies in 5 (11%), IgG antibodies in 35 (74%), and both IgM and IgG antibodies in 7 (15%). Of the 99 cases, 51% were asymptomatic during the epidemic; 61% had ground-glass or patchy opacities on CT of the chest compared with 11.6% among uninfected patients (P<0.001). Patients with hypertensive kidney disease were more often found to have SARS-CoV-2 infection and were more likely to be symptomatic than patients with another primary cause of kidney failure.
Possible false-positive and false-negative results for both NAT and antibody testing; possible lack of generalizability to other dialysis populations.
Half the SARS-CoV-2 infections in patients receiving MHD were subclinical and were not identified by universal CT of the chest and selective NAT. Serologic testing may help evaluate the overall prevalence and understand the diversity of clinical courses among patients receiving MHD who are infected with SARS-CoV-2.

BACKGROUND: The highest incidence of human immunodeficiency virus infection in China is among men who have sex with men. This case report aims to describe the dynamic changes in biomarkers in an acute human immunodeficiency virus infection of a Han Chinese man who has sex with men, and to illustrate the possibility of using these biomarkers for the early detection of human immunodeficiency virus infection in Chinese hospital settings.
METHODS: The 25-year-old Han Chinese male patient presented himself with an 8-day history of symptoms and signs of upper respiratory viral infections to a sexually transmitted infection clinic of a hospital setting in Shanghai. The viral load of human immunodeficiency virus, p24 antigen-antibody complex, and lymphocyte subsets of blood samples were repeatedly measured over the next 39 days. The human immunodeficiency virus from serum was genotyped. This patient was diagnosed as a human immunodeficiency virus infection, and the viral genotype was CRF 01_AE. The onset of the symptoms and signs was 12 days after his last reported unprotected intercourse with a human immunodeficiency virus -infected man. The patient had detectable levels of p24 antigen at his first visit, 20 days after infection, and the HIV viral load was at the highest point (8 × 106 copies/ml). A low concentration of antibody to HIV was observed in the patient\'s serum 10 days after his 1st visit (30 days after infection). The confirmation of human immunodeficiency virus infection by Western blot assays was made at day 20 after his 1st visit (40 days after infection).
CONCLUSIONS: Symptoms of acute human immunodeficiency virus infection are non-specific. Specific laboratory markers appear shortly after HIV infections. The first biomarker detected from serum is the viral RNA and p24 antigen, followed by HIV-specific antibody. The results suggest that there are urgent needs for both human immunodeficiency virus antigen and antibody testing in routine medical practice, and that human immunodeficiency virus RNA testing should be recommended to detect early infection. Ethics approval was obtained from the Ethics Board of the Shanghai Dermatology Hospital.