Serum KL-6 Could Represent a Reliable Indicator of Unfavourable Outcome in Patients with COVID-19 Pneumonia

KL-6 is a sialoglycoprotein antigen which proved elevated in the serum of patients with different interstitial lung diseases, especially in those with a poorer outcome. Given that interstitial pneumonia is the most common presentation of SARS-CoV2 infection, we evaluated the prognostic role of KL-6 in patients with COVID-19 pneumonia. Patients with COVID-19 pneumonia were prospectively enrolled. Blood samples were collected at the time of enrolment (TOE) and on day 7 (T1). Serum KL-6 concentrations were measured by chemiluminescence enzyme immunoassay using a KL-6 antibody kit (LUMIPULSE G1200, Fujirebio) and the cut-off value was set at >1000 U/mL. Fifteen out of 34 enrolled patients (44.1%) died. Patients with unfavourable outcome showed significantly lower P/F ratio and higher IL-6 values and plasmatic concentrations of KL-6 at TOE compared with those who survived (median KL-6: 1188 U/mL vs. 260 U/mL, p < 0.001). KL-6 > 1000 U/mL resulted independently associated with death (aOR: 11.29, p < 0.05) with a positive predictive value of 83.3%. Our results suggest that KL-6 is a reliable indicator of pulmonary function and unfavourable outcome in patients with COVID-19 pneumonia. A KL-6 value > 1000 U/mL resulted independently associated with death and showed good accuracy in predicting a poorer outcome. KL-6 may thus represent a quick, inexpensive, and sensitive parameter to stratify the risk of severe respiratory failure and death.

Seroprevalence of antibodies to SARS-CoV-2 is particularly high in patient population with ocular surface diseases

Coronavirus disease 2019 (COVID-19), a novel respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in December 2019. It is vitally important to perform a seroprevalence study to estimate the percentage of people with SARS-CoV-2 antibodies in the patient population with ocular surface diseases. IgG and IgM antibodies against the SARS-CoV-2 spike protein and nucleoprotein were measured using a commercially available magnetic chemiluminescence enzyme immunoassay kit. Throat swabs were tested for SARS-CoV-2 RNA in a designated virology laboratory. A total of 6, 414 individuals were enrolled. All participants throat swabs were RT-PCR-negative for SARS-CoV-2. Seroprevalence in the patient population was 0.31%. And the seroprevalevce in ocular surface diseases, no-ocular surface diseases and no-ocular diseases are 1.82% (6/330), 0.22% (10/4614) and 0.27% (4/1470) respectively.

A Peptide-Based Magnetic Chemiluminescence Enzyme Immunoassay for Serological Diagnosis of Coronavirus Disease 2019

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel β-coronavirus, causes severe pneumonia and has spread throughout the globe rapidly. The disease associated with SARS-CoV-2 infection is named coronavirus disease 2019 (COVID-19). To date, real-time reverse-transcription polymerase chain reaction (RT-PCR) is the only test able to confirm this infection. However, the accuracy of RT-PCR depends on several factors; variations in these factors might significantly lower the sensitivity of detection. Methods In this study, we developed a peptide-based luminescent immunoassay that detected immunoglobulin (Ig)G and IgM. The assay cutoff value was determined by evaluating the sera from healthy and infected patients for pathogens other than SARS-CoV-2. Results To evaluate assay performance, we detected IgG and IgM in the sera from confirmed patients. The positive rate of IgG and IgM was 71.4% and 57.2%, respectively. Conclusions Therefore, combining our immunoassay with real-time RT-PCR might enhance the diagnostic accuracy of COVID-19.

Serosurvey of anti-Toxoplasma gondii antibodies in homeless persons of São Paulo city, southeastern Brazil

Background: Seroprevalence of Toxoplasma gondii has been extensively studied in a variety of vulnerable populations. However, no study has focused on homeless populations. Accordingly, the present study aimed to assess the seroprevalence of anti-T. gondii antibodies and the risk factors associated in homeless persons from homeless shelter of São Paulo city, southeastern Brazil. In addition, anti-HIV antibodies and associated risk of T. gondii and HIV coinfection have been evaluated.Methods: Anti-T. gondii antibodies were detected by indirect fluorescent antibody test. In addition, anti-HIV levels were testedby chemiluminescence enzyme immunoassay, with positive samples confirmed by rapid immunoblot assay.Results: Overall, IgG anti-T. gondii seropositivity was found in 43/120 (35.8%) homeless persons, with endpoint titers varying from 16 to 1,024. The only two pregnant womentested were negative for IgM by chemiluminescence enzyme immunoassay, with normal parturition and clinically healthy newborns in both cases. There were no statistical differences in the risk factors for anti-T. gondii serology (p>0.05). Anti-HIV seropositivity was found in 2/120 (1.7%) homeless persons, confirmed as HIV-1. One HIV seropositive individual was also sero-reactive to IgG anti-T.gondii, and both were negative to IgM anti-T. gondii.Conclusions: This is the first study that reports the serosurvey of T. gondii in homeless persons worldwide. Despite the limited sample size available in the present study, our findings have shown that the prevalence of anti-T. gondii antibodies in homeless persons herein was lower than the general population, probably due to homeless diet habit of eating mainly processed food intake. No statistical differences were found regarding risk factors for anti-T. gondii exposure in homeless persons.

Serosurvey of anti-Toxoplasma gondii and anti-HIV antibodies in homeless persons of southeastern Brazil

Background: Homeless persons have been described as one of the most vulnerable populations worldwide, with higher morbidity and mortality of diseases associated with HIV occurrence. Seroprevalence of Toxoplasma gondii and HIV has been extensively studied in other vulnerable populations, however, no study to date have focused on their concomitant seroprevalence in homeless persons. Accordingly, the present study aimed to assess the concomitant seroprevalence of anti-T. gondii and anti-HIV antibodies and associated risk factors in homeless persons in a daytime homeless shelter of São Paulo, southeastern Brazil. Methods: Anti-T. gondii antibodies were detected by indirect fluorescent antibody test and anti-HIV levels by chemiluminescence enzyme immunoassay, with positive samples confirmed by rapid immunoblot assay. Results: Overall, IgG anti-T. gondii seropositivity was found in 43/120 (35.8%) homeless persons, with endpoint titers varying from 16 to 1,024. The only two pregnant women tested were negative for IgM by chemiluminescence enzyme immunoassay, with normal parturition and clinically healthy newborns in both cases. There were no statistical differences in the risk factors for anti-T. gondii serology (p>0.05). Anti- HIV seropositivity was found in 2/120 (1.7%) homeless persons, confirmed as HIV-1. One HIV seropositive individual was also sero-reactive to IgG anti-T. gondii, and both were negative to IgM anti-T. gondii. One HIV positive person was also diagnosed with syphilis, tuberculosis and body lice presence, while the other never returned for assistance. No evaluation of anti- HIV risk factors has been made due to the low seropositive rate. Conclusions: The anti-T. gondii prevalence herein was lower than other Brazilian populations, likely related to predominant intake of processed food such as ready-to-eat and fast-food meals, and thus, low ingestion of fresh salad and raw meat. On the other hand, the anti- HIV seropositivity was higher than the average of the general Brazilian population, with 0.4%. Despite the low prevalence of anti-T. gondii in homeless persons, clinical manifestations may be aggravated in HIV positive individuals. To the author's knowledge, this is the first study of anti-T. gondii serosurvey in homeless persons concomitantly assessed with anti-HIV seropositivity.