A flow cytometry-based assay to measure neutralizing antibodies against SARS-CoV-2 virus.

The COVID-19 pandemic caused by the SARS-CoV-2 virus has highlighted the need for serological assays that can accurately evaluate the neutralizing efficiency of antibodies produced during infection or induced by vaccines. However, conventional assays often require the manipulation of live viruses on a level-three biosafety (BSL3) facility, which presents practical and safety challenges. Here, we present a novel, alternative assay that measures neutralizing antibodies (NAbs) against SARS-CoV-2 in plasma using flow cytometry. This assay is based on antibody binding to the S protein and has demonstrated precision in both intra- and inter-assay measurements at a dilution of 1:50. The cut-off was determined using Receiver Operating Characteristic (ROC) analysis and the value of 36.01% has shown high sensitivity and specificity in distinguishing between pre-pandemic sera, COVID-19 patients, and vaccinated individuals. The efficiency significantly correlates with the gold standard test, PRNT. Our new assay offers a safe and efficient alternative to conventional assays for evaluating NAbs against SARS-CoV-2.

Surgical resection therapy of a rare presentation of persistent Mullerian duct syndrome: a case review.

Persistent Mullerian Duct Syndrome (PMDS) is an extremely rare disease with less than 300 cases recorded in medical literature. Our patient was a 37 year old male who presented at the medical office with hematospermia as his sole complaint. He had previously undergone left orchidopexy and presented with hypotrophic left testicle and right testicle agenesis. PMDS differential was considered with the clear observation of a uterus-like structure during pelvic ultrasonography. The organs were later studied in magnetic resonance imaging and confirmed by post-surgery anatomopathological examination. Patient was discharged 24 h after surgery and developed azoospermia post-surgery.

Operative correction of an extremely rare condition called Persistent Mullerian Duct Syndrome (PMDS). What is PMDS? PMDS is a disease which has less than 300 cases in medical literature. It is a congenital condition characterized by the development of female genital organs such as the uterus and ovaries, in an otherwise normal male individual. The fetal development of these structures begins when the male fetus develops his genitalia, during the period when he must produce a hormone (anti-mullerian hormone), which suppresses female genitalia growth. Since this fetal stage is the turning point for genital development, lack of this hormone commonly results in the presence of functional female genital organs in an adult male, which characterizes the syndrome. Multiple reports also associate the syndrome with ectopic testis (cryptorchidism) or gonadal absence and dysfunctional sexual cell production. What was the aim of the report? The aim is to present a rare presentation of an already extremely rare disease in order to enrich the literature with another case of PMDS and the outcome of surgical correction. How was the patient treated? After discovering female organs in the male pelvis during an ultrasound scan, an elective surgery was performed to evaluate the removal of the uterus, fallopian tubes, ovary and vaginal canal through video laparoscopy. Why is this case important? The overall medical knowledge about PMDS is rather limited due to the reduced number of cases and the relatively wide variety of presentations. This article is useful to present a rather rare presentation, in which cryptorchidism and testicular agenesis were concomitant with hematospermia. Other than that, the diagnosis was done late in the patient's life, having lived over three decades with female genitals in his pelvis without any malignant (cancerous) mutations. The case report can also provide a record for the outcome of azoospermia, which is the absence of motile (and hence viable) sperm in the semen, following a non-complicated post-surgical recovery, which suggests unknown mechanisms may be involved in gonadal development after birth, and a different endocrine balance in patients with the syndrome.

Pediatric COVID-19 patients in South Brazil show abundant viral mRNA and strong specific anti-viral responses.

COVID-19 manifests as a milder disease in children than adults, but the underlying mechanisms are not fully characterized. Here we assess the difference in cellular or humoral immune responses of pediatric and adult COVID-19 patients to see if these factors contribute to the severity dichotomy. Children's non-specific immune profile is dominated by naive lymphocytes and HLA-DRhighCX3CR1low dendritic cells; meanwhile, children show strong specific antibody and T cell responses for viral structural proteins, with their T cell responses differing from adults by having weaker CD8+TNF+ T cells responses to S peptide pool but stronger responses to N and M peptide pools. Finally, viral mRNA is more abundant in pediatric patients. Our data thus support a scenario in which SARS-CoV-2 infected children contribute to transmission yet are less susceptible to COVID-19 symptoms due to strong and differential responses to the virus.