Multi-parameter approach to evaluate the timing of memory status after 17DD-YF primary vaccination.

In this investigation, machine-enhanced techniques were applied to bring about scientific insights to identify a minimum set of phenotypic/functional memory-related biomarkers for post-vaccination follow-up upon yellow fever (YF) vaccination. For this purpose, memory status of circulating T-cells (Naïve/early-effector/Central-Memory/Effector-Memory) and B-cells (Naïve/non-Classical-Memory/Classical-Memory) along with the cytokine profile (IFN/TNF/IL-5/IL-10) were monitored before-NV(day0) and at distinct time-points after 17DD-YF primary vaccination-PV(day30-45); PV(year1-9) and PV(year10-11). A set of biomarkers (eEfCD4; EMCD4; CMCD19; EMCD8; IFNCD4; IL-5CD8; TNFCD4; IFNCD8; TNFCD8; IL-5CD19; IL-5CD4) were observed in PV(day30-45), but not in NV(day0), with most of them still observed in PV(year1-9). Deficiencies of phenotypic/functional biomarkers were observed in NV(day0), while total lack of memory-related attributes was observed in PV(year10-11), regardless of the age at primary vaccination. Venn-diagram analysis pre-selected 10 attributes (eEfCD4, EMCD4, CMCD19, EMCD8, IFNCD4, IL-5CD8, TNFCD4, IFNCD8, TNFCD8 and IL-5CD4), of which the overall mean presented moderate accuracy to discriminate PV(day30-45)&PV(year1-9) from NV(day0)&PV(year10-11). Multi-parameter approaches and decision-tree algorithms defined the EMCD8 and IL-5CD4 attributes as the top-two predictors with moderated performance. Together with the PRNT titers, the top-two biomarkers led to a resultant memory status observed in 80% and 51% of volunteers in PV(day30-45) and PV(year1-9), contrasting with 0% and 29% found in NV(day0) and PV(year10-11), respectively. The deficiency of memory-related attributes observed at PV(year10-11) underscores the conspicuous time-dependent decrease of resultant memory following17DD-YF primary vaccination that could be useful to monitor potential correlates of protection in areas under risk of YF transmission.

Systemic Immunological changes in patients with distinct clinical outcomes during Mycobacterium tuberculosis infection.

BACKGROUND: The lung lesions in an individual infected with tuberculosis (TB) are surprisingly variable and independent of each other. However, there is no circulating biomarker yet able to segregate patients according to the extent of lung lesions. MATERIALS AND METHODS: In this study, the phenotypic and functional profile of leukocytes of patients with active pulmonary tuberculosis (TB) and controls (CO) were fully scrutinized by immunophenotyping assays and in vitro short-term whole blood culture. The TB group was subdivided according to the extent of lung lesions as unilateral (UNI) and bilateral (BI). RESULTS: The results show that TB group display an altered leukocyte profile in the peripheral blood with significant lower counts of NK-cells, CD3+CD56+CD16+/- NKT-cells, CD4+T-cells, CD19+B-cells when compared to CO. Increased CD4+T-cells and CD8+T-cell activation was observed by the upregulation of activation markers (HLA-DR) as well as of chemokine receptors (CCR2, CCR3, and CXCR4). In addition, TB group presented a significant decrease proportion of CD14LowCD16+ monocytes despite the increase in HLA-DR expression. Regarding the severity of the disease, in the BI group a reduction in frequency of CD19+CD5+ B-cells and expression of HLA-DR in CD14LowCD16+ monocytes was observed. Furthermore, the extent of lung lesions influences the production of molecules as observed by significantly larger production of IL-4 by neutrophils, total T-cells, CD4+T-cells, CD8+T-cells and CD19+B-cells in UNI as compared to BI. By contrast, in BI group the frequency of high producers of both IL-17+CD4+T-cells and IL-17+CD8+T-cells were significantly increased than UNI, suggesting the deleterious role of these subsets during active pulmonary Mtb infection. CONCLUSION: The immunophenotypic characterization of unilateral and bilateral active TB performed in the present study indicates that the extent of lung lesion could be associated with a fine-tuning between immunological responses during untreated Mtb infection.