ABSTRACT
The measurement of specific T-cell responses can be a useful tool for COVID-19 diagnostics and clinical management. In this study, we evaluated the IFN-γ T-cell response against the main SARS-CoV-2 antigens (spike, nucleocapsid and membrane) in acute and convalescent individuals classified according to severity, and in vaccinated and unvaccinated controls. IgG against spike and nucleocapsid were also measured. Spike antigen triggered the highest number of T-cell responses. Acute patients showed a low percentage of positive responses when compared to convalescent (71.6% vs. 91.7%, respectively), but increased during hospitalization and with severity. Some convalescent patients showed an IFN-γ T-cell response more than 200 days after diagnosis. Only half of the vaccinated individuals displayed an IFN-γ T-cell response after the second dose. IgG response was found in a higher percentage of individuals compared to IFN-γ T-cell responses, and moderate correlations between both responses were seen. However, in some acute COVID-19 patients specific T-cell response was detected, but not IgG production. We found that the chances of an IFN-γ T-cell response against SARS-CoV-2 is low during acute phase, but may increase over time, and that only half of the vaccinated individuals had an IFN-γ T-cell response after the second dose.
ABSTRACT
Background: Current blood-based diagnostic tools for TB are insufficient to properly characterize the distinct stages of TB, from the latent infection (LTBI) to its active form (aTB); nor can they assess treatment efficacy. Several immune cell biomarkers have been proposed as potential candidates for the development of improved diagnostic tools. Objective: To compare the capacity of CD27, HLA-DR, CD38 and Ki-67 markers to characterize LTBI, active TB and patients who ended treatment and resolved TB. Methods: Blood was collected from 45 patients defined according to clinical and microbiological criteria as: LTBI, aTB with less than 1 month of treatment and aTB after completing treatment. Peripheral blood mononuclear cells were stimulated with ESAT-6/CFP-10 or PPD antigens and acquired for flow cytometry after labelling with conjugated antibodies against CD3, CD4, CD8, CD27, IFN-γ, TNF-α, CD38, HLA-DR, and Ki-67. Conventional and multiparametric analyses were done with FlowJo and OMIQ, respectively. Results: The expression of CD27, CD38, HLA-DR and Ki-67 markers was analyzed in CD4+ T-cells producing IFN-γ and/or TNF-α cytokines after ESAT-6/CFP-10 or PPD stimulation. Within antigen-responsive CD4+ T-cells, CD27- and CD38+ (ESAT-6/CFP-10-specific), and HLA-DR+ and Ki-67+ (PPD- and ESAT-6/CFP-10-specific) populations were significantly increased in aTB compared to LTBI. Ki-67 demonstrated the best discriminative performance as evaluated by ROC analyses (AUC > 0.9 after PPD stimulation). Data also points to a significant change in the expression of CD38 (ESAT-6/CFP-10-specific) and Ki-67 (PPD- and ESAT-6/CFP-10-specific) after ending the anti-TB treatment regimen. Furthermore, ratio based on the CD27 median fluorescence intensity in CD4+ T-cells over Mtb-specific CD4+ T-cells showed a positive association with aTB over LTBI (ESAT-6/CFP-10-specific). Additionally, multiparametric FlowSOM analyses revealed an increase in CD27 cell clusters and a decrease in HLA-DR cell clusters within Mtb-specific populations after the end of treatment. Conclusion: Our study independently confirms that CD27-, CD38+, HLA-DR+ and Ki-67+ populations on Mtb-specific CD4+ T-cells are increased during active TB disease. Multiparametric analyses unbiasedly identify clusters based on CD27 or HLA-DR whose abundance can be related to treatment efficacy. Further studies are necessary to pinpoint the convergence between conventional and multiparametric approaches.
ABSTRACT
BACKGROUND: Changes in hematological parameters in patients with COVID-19 are emerging as important features of the disease in the general population. In the present study we aimed to explore the hematological characteristics and its prevalence proportion ratio in patients with immunosuppression with COVID-19. AIM: To explore the differences between immunosuppressed and non-immunosuppressed patients, with and without COVID-19 from a hematological perspective. METHODS: This cross-sectional study reports on the baseline complete blood count in patients attending the HHA Hospital, in Chile. The study reports descriptive characteristics of the population, including sex, age, ethnicity, corticoids and biological therapy scheme and a complete report of blood test results. A total of 476 patients were enrolled in this study from October of 2020 to April 2021. RESULTS: Findings revels a significant increment (p value ≤ 0.001) on the median of total neutrophils and leucocytes, and in platelet-lymphocyte ratio (PLR), neutrophil- lymphocyte ratio (NLR) and monocyte-lymphocyte ratio (MLR) in immunosuppressed patients with COVID-19 (IS(+)) and immunocompetent patients with COVID-19 (IC(+)) compared with their respective controls. By contrast, a significant reduction on the median of lymphocytes, and eosinophiles was observed in IS(+) individuals compared with its controls. Also, the red blood cell count, hemoglobin, hematocrit, and mean corpuscular hemoglobin concentration were significantly reduced in IS(+) patients, whereas red blood cell, distribution width and mean corpuscular volume, were significantly higher in patients with COVID-19. CONCLUSION: Rapid blood tests, including, neutrophil, lymphocytes count and PLR, NLR can be used for early assessment and management of patients with immunosuppression.
