Long Lasting Cellular Immune Response Induced by mRNA Vaccination: Implication for Prevention Strategies.

As the COVID19 pandemic continues to spread and vaccinations are administered throughout the world at different rates and with different strategies, understanding the multiple aspects of the immune response to vaccinations is required to define more efficient vaccination strategies. To date, the duration of protection induced by COVID19 vaccines is still matter of debate. To assess whether 2-doses vaccination with BNT162b2 mRNA COVID-19 vaccine was sufficient to induce a persistent specific cellular immune response, we evaluated the presence of SARS-COV2 Spike-specific B and T lymphocytes in 28 healthcare workers 1 and 7 months after completing the vaccination cycle. The results showed that at 7 months after second dose a population of Spike-specific B lymphocytes was still present in 86% of the immunized subjects, with a higher frequency when compared to not-immunized controls (0.38% ± 0.07 vs 0.13% ± 0.03, p<0.001). Similarly, specific CD4+ and CD8+ T lymphocytes, able to respond in vitro to stimulation with Spike derived peptides, were found at 7 months. These results confirm that vaccination with BNT162b2 is able to induce a specific immune response, potentially long lasting, and could be helpful in defining future vaccination strategies.

Soluble P-selectin as a marker of in vivo platelet activation.

BACKGROUND: Platelets are the major source of circulating sP-selectin. Elevated levels of this protein have been found in many atherothrombotic disorders. Thus, we investigated whether sP-selectin dosage might reflect platelet function in patients with risk factors for or with established cardiovascular diseases and whether its levels can be modulated by aspirin therapy. METHODS: Plasma sP-selectin levels and light transmission platelet aggregometry (LTA) were analyzed in 152 outpatients. The effects of a 6-month aspirin therapeutic course on sP-selectin levels and LTA in 51 consecutive patients have been also investigated. RESULTS: Significant correlations were observed between sP-selectin and Mx% LTA in response to epinephrine (p=0.022) and arachidonic acid (p=0.006), or between sP-selectin and collagen lag-phase (p=0.016). Multiple regression analysis showed that the only predictors of sP-selectin levels were platelet number (p<0.001) and collagen-induced lag-phase (p<0.01). Aspirin-treated patients showed a significant reduction of sP-selectin levels by 13% (p=0.021) which significantly correlated with collagen-induced lag-phase (p=0.005). CONCLUSIONS: sP-selectin dosage could be proposed as a reliable marker of platelet activation in patients with major atherosclerotic risk factors either in the absence of clinically overt disease, and might represent a valid tool to asses in vivo platelet behavior.

Prognostic value of pre-surgical plasma PAI-1 (plasminogen activator inhibitor-1) levels in breast cancer.

INTRODUCTION: Plasminogen activator inhibitor (PAI-1) may have an independent prognostic value in breast cancer (BC). PAI-1 4G/5G polymorphism may have significance for antigen expression. Thus, we analyzed the possible associations between PAI-1 4G/5G polymorphism, plasma PAI-1 levels, and clinicopathological features of breast cancer (BC) patients. PATIENTS AND METHODS: PAI-1 4G/5G polymorphism (both on germinal and tumor DNA) and plasma PAI-1 levels were investigated in 99 BC patients and 50 unrelated healthy women similar for age and menopausal status. RESULTS: No association was found between allele frequencies and clinicopathological features of BC or plasma antigen levels. Plasma PAI-1 levels were higher in BC compared to controls (p=0.002), particularly in patients with large tumors (p<0.001). 5-year follow-up was achieved in 79 patients: 30% had relapsing disease, 63% with positive compared to 37% with negative PAI-1 levels (p<0.05). 5-year relapse-free survival rate of positive PAI-1 was 46% vs., 77% of negative patients (p=0.02). CONCLUSIONS: We may conclude that plasma PAI-1 levels in BC patients could represent a useful prognostic variable for relapse, although PAI-1 polymorphism might not represent a genetic susceptibility factor.