ABSTRACT
COVID-19 is caused by the human pathogen severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has resulted in widespread morbidity and mortality. CD4+ T cells, CD8+ T cells and neutralizing antibodies all contribute to control SARS-CoV-2 infection. However, heterogeneity is a major factor in disease severity and in immune innate and adaptive responses to SARS-CoV-2. We performed a deep analysis by flow cytometry of lymphocyte populations of 125 hospitalized SARS-CoV-2 infected patients on the day of hospital admission. Five clusters of patients were identified using hierarchical classification on the basis of their immunophenotypic profile, with different mortality outcomes. Some characteristics were observed in all the clusters of patients, such as lymphopenia and an elevated level of effector CD8+CCR7- T cells. However, low levels of T cell activation are associated to a better disease outcome; on the other hand, profound CD8+ T-cell lymphopenia, a high level of CD4+ and CD8+ T-cell activation and a high level of CD8+ T-cell senescence are associated with a higher mortality outcome. Furthermore, a cluster of patient was characterized by high B-cell responses with an extremely high level of plasmablasts. Our study points out the prognostic value of lymphocyte parameters such as T-cell activation and senescence and strengthen the interest in treating the patients early in course of the disease with targeted immunomodulatory therapies based on the type of adaptive response of each patient.
ABSTRACT
BACKGROUND: Evaluation of skin microcirculation in patients with critical limb ischemia (CLI) may be achieved by the measurement of transcutaneous oxygen pressure or skin perfusion pressure, but there is no practical method available for the evaluation of muscle microcirculation. Contrast enhanced ultrasonography (CEUS) has been used to assess muscle perfusion in patients with peripheral arterial disease. We conducted a monocentric pilot study evaluating the ability of CEUS to assess the impact of arterial revascularization on the perfusion of the calf muscle in patients with CLI. PATIENTS AND METHODS: Patients with CLI (TASC II criteria) and a possibility of proximal or medial revascularization were included. In addition to TcPO2 and toe systolic blood pressure measurements, CEUS of the calf muscle was performed just before and one month after the therapeutic procedure. Parameters derived from muscular perfusion curves were evaluated in a blinded fashion and compared with the clinical outcome. RESULTS: Thirty eight patients were included (74 % men, median age 71 years, 53 % diabetics). Thirty benefited from revascularization with a clinical success rate of 70 %. Twenty three patients could benefit from analysis before and after revascularization. No significant difference was shown in time to peak (22.3 s vs 24.0 s, P = 0.61) nor in peak intensity (2.30 dB vs 1.27 db, P = 0,26), contrasting with significant improvements of TcPO2 (43 mm Hg vs 20 mm Hg, P = 0.007) and toe systolic blood pressure (54 mm Hg vs 32 mm Hg, P = 0.002). CONCLUSIONS: The evaluation of muscular microvascular perfusion by CEUS as performed in this study is not enough sensitive to change to allow a clinically relevant evaluation of the improvement in muscle microvascular perfusion in patients with CLI benefiting from revascularization procedures.
