ABSTRACT
The efficacy of virus-specific T cells in clearing pathogens involves a fine balance between their antiviral and inflammatory features. SARS-CoV-2-specific T cells in individuals who clear SARS-CoV-2 infection without symptoms or disease could reveal non-pathological yet protective characteristics. We therefore compared the quantity and function of SARS-CoV-2-specific T cells in a cohort of asymptomatic individuals (n=85) with that of symptomatic COVID-19 patients (n=76), at different time points after antibody seroconversion. We quantified T cells reactive to structural proteins (M, NP and Spike) using ELISpot assays, and measured the magnitude of cytokine secretion (IL-2, IFN-{gamma}, IL-4, IL-6, IL-1{beta}, TNF- and IL-10) in whole blood following T cell activation with SARS-CoV-2 peptide pools as a functional readout. Frequencies of T cells specific for the different SARS-CoV-2 proteins in the early phases of recovery were similar between asymptomatic and symptomatic individuals. However, we detected an increased IFN-{gamma} and IL-2 production in asymptomatic compared to symptomatic individuals after activation of SARS-CoV-2-specific T cells in blood. This was associated with a proportional secretion of IL-10 and pro-inflammatory cytokines (IL-6, TNF- and IL-1{beta}) only in asymptomatic infection, while a disproportionate secretion of inflammatory cytokines was triggered by SARS-CoV-2-specific T cell activation in symptomatic individuals. Thus, asymptomatic SARS-CoV-2 infected individuals are not characterized by a weak antiviral immunity; on the contrary, they mount a robust and highly functional virus-specific cellular immune response. Their ability to induce a proportionate production of IL-10 might help to reduce inflammatory events during viral clearance.
ABSTRACT
BackgroundThe SARS-CoV-2 shares 74.5% genome identity with SARS-CoV, both exhibiting a similar well conserved structure. Therefore, antibodies produced in COVID-19 and SARS patients should not be that dissimilar. We evaluated SARS-CoV test assays to detect for the presence of antibodies to SARS-CoV-2 and tried to determine the timing of appearance of these antibodies by testing serial sera from these patients. MethodsTests were carried out using ELISA (total antibodies) and indirect immunofluorescence (IIFA) (IgM & IgG) methods on serial sera from patients confirmed with SARS-CoV-2 infection. ResultsCross-reactivity was seen in these two test assays with sera from COVID-19 patients and was detected in 6 out of 7 patients from 7 days after onset of symptoms. Five of the patients had detectable antibodies by the 3rd week into their illness and there was evidence of seroconversion in 4 patients. The IIFA method was marginally more sensitive compared to the ELISA assay, however the IIFA IgM test was not useful in the early phase of the illness with poor sensitivity. ConclusionsExisting diagnostic assays for SARS-CoV can detect antibodies in patients who were diagnosed with COVID-19. These assays maybe be utilized as an interim measure in epidemiological investigations for contact tracing and to determine the extent of community spread of this new emerging virus pending the availability of specific serology tests for SARS-CoV-2.
ABSTRACT
<p><b>INTRODUCTION</b>Awake craniotomy allows accurate localisation of the eloquent brain, which is crucial during brain tumour resection in order to minimise risk of neurologic injury. The role of the anaesthesiologist is to provide adequate analgesia and sedation while maintaining ventilation and haemodynamic stability in an awake patient who needs to be cooperative during neurological testing. We reviewed the anaesthetic management of patients undergoing an awake craniotomy procedure.</p><p><b>MATERIALS AND METHODS</b>The records of all the patients who had an awake craniotomy at our institution from July 2004 till June 2006 were reviewed. The anaesthesia techniques and management were examined. The perioperative complications and the outcome of the patients were noted.</p><p><b>RESULTS</b>There were 17 procedures carried out during the study period. Local anaesthesia with moderate to deep sedation was the technique used in all the patients. Respiratory complications occurred in 24% of the patients. Hypertension was observed in 24% of the patients. All the complications were transient and easily treated. During cortical stimulation, motor function was assessed in 16 patients (94%). Three patients (16%) had lesions in the temporal-parietal region and speech was assessed intraoperatively. Postoperative motor weakness was seen in 1 patient despite uneventful intraoperative testing. No patient required intensive care unit stay. The median length of stay in the high dependency unit was 1 day and the median length of hospital stay was 9 days. There was no in-hospital mortality.</p><p><b>CONCLUSION</b>Awake craniotomy for brain tumour excision can be successfully performed under good anaesthetic conditions with careful titration of sedation. Our series showed it to be a well-tolerated procedure with a low rate of complications. The benefits of maximal tumour excision can be achieved, leading to potentially better patient outcome.</p>
