No clear correlation was observed among the IgA, IgG, and IgM-positive samples. == Table3. hospitalization. The positive rates increased when combining saliva IgA and viral nucleic acid detection. In conclusion, our results provide evidence that saliva IgA could serve as a useful index for the early Rabbit polyclonal to DARPP-32.DARPP-32 a member of the protein phosphatase inhibitor 1 family.A dopamine-and cyclic AMP-regulated neuronal phosphoprotein.Both dopaminergic and glutamatergic (NMDA) receptor stimulation regulate the extent of DARPP32 phosphorylation, but in opposite directions.Dopamine D1 receptor stimulation enhances cAMP formation, resulting in the phosphorylation of DARPP32 diagnosis of COVID-19. Keywords:COVID-19, SARS-CoV-2, immunoglobulins, saliva IgA, diagnose == Introduction == The pneumonia outbreak in Wuhan, China in December 2019 was caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Currently, the coronavirus disease (COVID-19) pandemic is developing rapidly into a dramatically devastating public health crisis. By April 2021, reported cases of COVID-19 had exceeded 147 million worldwide, with at least 3,144,381 deaths. Molecular assays on nasopharyngeal swabs are confirmatory tests BMS-191095 for COVID-19 diagnosis (1). Despite massive efforts, the positive rate of RNA detection for SARS-CoV-2 was 63% in nasopharyngeal swabs and only 32% in pharyngeal swabs (2). Serological assays play an important role in the clinical diagnosis of COVID-19. IgM and IgG-based assays are the gold standard for serological diagnosis in COVID-19 (3). SARS-CoV-2 S1 and N antigens have been detected in the serum of SARS-CoV-2 infected patients, which help detect active infection and monitor disease progression in COVID-19 patients (4). Currently, nasopharyngeal swabs are the main recommended upper respiratory tract specimen types for the COVID-19 test, whereas the use of saliva for the diagnosis of the disease has recently been suggested (5,6). Saliva specimens could be obtained conveniently. The collection of saliva is noninvasive and greatly minimizes the exposure of healthcare workers to COVID-19 (7). The detection of SARS-CoV-2 salivary antibodies could serve as a non-invasive alternative to serological tests (8). Saliva is secreted by salivary glands, which is characteristic of abundant IgA. Usually, salivary IgG and IgM concentrations are much BMS-191095 lower than those in the serum (9). It has been hypothesized that both salivary IgG and IgM are derived from blood, whereas IgA is mainly produced by the salivary glands (10). A recent study reported that salivary IgA was associated with the presence of pneumonia but unassociated with serum immunoglobulins (11). These results suggest that salivary IgA is independent of serum immunoglobulins. In this study, we measured saliva and serum specimens from 44 COVID-19 patients and 24 negative control patients. The associations between saliva and serum immunoglobulins were analyzed and the potential of saliva IgA in COVID-19 diagnosis was assessed. == Materials and Methods == == Patients == A total of 44 patients diagnosed with COVID-19 based on the World Health Organizations interim guidance, from 1 August to 1 1 September 2020, at The Third Peoples Hospital of Shenzhen were enrolled in this study. A total of 24 negative-control patients with no SARS-CoV-2 infection were selected randomly from inpatient departments. The study was approved by the Ethics Committee of The Third Peoples Hospital of Shenzhen. Written informed consent was obtained from all participants enrolled in the study. == Immunoglobulin Measurement == A total 180 of saliva specimens and 181 peripheral blood specimens were obtained from COVID-19 patients with RT-PCR confirmed prior SARS-CoV-2 infection, at different time points during hospitalization. Saliva specimens and peripheral blood specimens were also obtained from negative-control patients. The serum specimens BMS-191095 were BMS-191095 obtained from the supernatant of centrifuged peripheral blood at 3,500 rpm for 5 min. The saliva specimens were centrifuged and the supernatants were collected for immunoglobulin detection. All specimens were inactivated at 56 C for 30 min. Immunoglobulins against SARS-CoV-2 surface spike protein receptor-binding domain (RBD) were measured by chemiluminescence kit (IgA, IgG, and IgM, Beijing Wantai Biotech, China) according to the instructions of the manufacturer. The relative fluorescence of the sample to control (COI) was used to estimate the result, with COI 1 as positive and <1 as negative. == Real-Time PCR == Over 240 swab samples were obtained from the upper respiratory tracts of participants, and SARS-CoV-2 was detected by RT-PCR assay as reported previously. Briefly, the nucleocapsid protein and open reading frame 1ab were amplified and examined with two pairs of primers. Each sample was detected in triplicate with positive and negative controls. The diagnostic criteria were based on the recommendations by the National Center for Disease Control and Prevention of China. == Statistical Analysis == Statistical analysis was performed using SPSS software version 22.0. A Students t-test was used to compare the difference between different antibodies in saliva. A paired t-test was used to analyze the difference in antibody COI between serum and saliva. == Results == Patients diagnosed with COVID-19 from 1 August to 1 1 September 2020 at The Third Peoples Hospital of Shenzhen were enrolled.