A Low Number of Baselines γδ T Cells Increases the Risk of SARS-CoV-2 Post-Vaccination Infection.

Background: The COVID-19 pandemic is the biggest global health problem in the last hundred years. The efficacy of the vaccine to protect against severe disease is estimated to be 70-95% according to the studies carried out, although there are aspects of the immune response to the vaccine that remain unclear. Methods: Humoral and cellular immunity after the administration of three doses of the Pfizer-BioNTech and Oxford AstraZeneca vaccines against SARS-CoV-2 over one year and the appearance of post-vaccination COVID-19 were studied. SARS-CoV-2 IgG and IgA antibodies, αß and γδ T-cell subsets, and their differentiation stages and apoptosis were analyzed. Results: Anti-SARS-CoV-2 IgG and IgA antibodies showed a progressive increase throughout the duration of the study. This increase was the greatest after the third dose. The highest levels were observed in subjects who had anti-SARS-CoV-2 antibodies prior to vaccination. There was an increase in CD4+ αß, CD8+ γδ and TEM CD8+ γδ T cells, and a decrease in apoptosis in CD4+ CD8+ and CD56+ αß and γδ T cells. Post-vaccination SARS-CoV-2 infection was greater than 60%. The symptoms of COVID-19 were very mild and were related to a γδ T cell deficit, specifically CD8+ TEMRA and CD56+ γδ TEM, as well as lower pre-vaccine apoptosis levels. Conclusions: The results unveil the important role of γδ T cells in SARS-CoV-2-vaccine-mediated protection from the disease.

Missing Cases of Herpes Simplex Virus (HSV) Infection of the Central Nervous System When the Reller Criteria Are Applied for HSV PCR Testing: a Multicenter Study.

Previous studies suggested that herpes simplex virus (HSV) PCR testing can be safely deferred in patients with normal cerebrospinal fluid (CSF) white blood cell (WBC) counts and protein levels as long as they are older than 2 years of age and are not immunocompromised, the so-called Reller criteria. In this multicenter study, we retrospectively assessed the validity of these screening criteria in our setting. A total of 4,404 CSF specimens submitted for HSV PCR testing to the respective microbiology laboratories at the participating hospitals between 2012 and 2018 were included. Six commercially available HSV PCR assays were used across the participating centers. Ninety-one of the 4,404 CSF specimens (2.1%) tested were positive for HSV DNA (75 samples for HSV-1 and 16 for HSV-2). Nine patients failed to meet the Reller criteria, of whom seven were deemed to truly have HSV encephalitis. Overall, no significant correlation between HSV PCR cycle threshold (CT ) values and WBC counts or total protein levels was found. In addition, median HSV PCR CT s were comparable between patients who met the Reller criteria and those who did not (P = 0.531). In summary, we show that HSV DNA may be detected in CSF specimens with normal WBC and protein levels collected from immunocompetent individuals older than 2 years with HSV encephalitis. Nevertheless, the data also indicate that the number of cases detected could be lowered at least by half if CSF specimens with borderline WBC counts (4 cells/mm3) as well as children of any age are systematically tested.

Occurrence and genotypes of Giardia isolated from lambs in Spain.

Three hundred and eighty six faecal specimens were randomly collected from 1- to 3-month-old lambs from 16 farms in Spain to investigate the presence of different genotypes of Giardia duodenalis. Individual specimens were examined by IFA (Immunofluorescence assay) and beta-giardin PCR polymerase chain reaction. Cysts of G. duodenalis were shed by lambs in every flock analyzed, showing a prevalence by farms of 100%. The average prevalence of G. duodenalis for the 386 specimens was 42%, ranging from 8.3 to 80% depending on the farm. beta-giardin PCR positive samples were sequenced to determine the genotypes present at each farm and seven new subtypes of beta-giardin Assemblage E are reported in this study. In each farm, one to six different beta-giardin subtypes were found, showing the high variability of the target. Also, one flock had the zoonotic Assemblage A. This is the first report of Giardia subgenotype A-1 in sheep in Spain.

[Molecular diagnosis of parasitic and fungal infections]. / El diagnóstico molecular en las infecciones parasitarias y fúngicas.

Conventional microbiological diagnosis of fungal infections and parasitic diseases has been characterized by low diagnostic sensitivity, laboriousness, and the need for expert microscopists. Consequently, diagnostic methods based on the detection of nucleic acids are a magnificent alternative to overcome these problems, but have not yet provided a satisfactory response in all situations. The molecular methods used are varied and most are based on techniques of nucleic acid amplification. These techniques have proved useful for mycological and parasitological diagnosis, for epidemiological and taxonomic studies, and for monitoring the response to different treatments and detection of resistance. The introduction of these techniques in developing countries may be hampered by their higher cost but molecular diagnostic methods are already beginning to spread in clinical microbiology laboratories and are competing successfully with traditional methods. The present article reviews the current status of molecular methods in the diagnosis of fungal and parasitic infections.