Impact of CT Scan Phenotypes in Clinical Manifestations, Management and Outcomes of Hospitalised Patients with COVID-19

COVID-19 is such a heterogeneous disease that a one-size-fits-all approach is not recommended, so the management of patients has been based on their clinical and laboratory characteristics. We therefore investigated possible homogeneous groups presenting similar features of lung involvement based on chest CT and laboratory results. We designed a study to identify a possible correlation between CT scan phenotypes, laboratory exams, and clinical outcomes. We retrospectively analysed 120 adult patients with COVID-19 5who underwent chest CT scan during hospitalisation, between March and December 2020 at our COVID-19 Hospital in two different wards: Respiratory Intensive Care Unit (RICU) and Intensive Care Unit (ICU). The analysis of CT scans resulted in the identification of three radiological phenotypes by two blinded pulmonologists (Cohen's κ = 0.9 for Phenotype 1, 0.9 for Phenotype 2 and 0.89 for Phenotype 3), in accordance with what previously described by Robba et al. “Phenotype 1” (PH1) is characterised by modest interstitial oedema with presentation on chest CT of diffuse ground glass opacities (GGO). “Phenotype 2” (PH2) shows predominant consolidation at lung lobes. “Phenotype 3” (PH3) shows a typical CT pattern of moderate-to-severe ARDS, with alveolar oedema. Based on our results, we could hypothesise that phenotype 2 shows a different trend from all the others and would seem to be more related to a coagulopathy, although we cannot exclude the hypothesis that one phenotype evolves from the other. Further studies might focus on the predictive role of D-dimer, and its cut-offs, in delineating the PH2 patients, that could require an early CT scan to avoid excessive pressure support and finally prevent VILI. To further understand the exact basis of the different CT scan phenotype, a longer longitudinal analysis of clinical and laboratory features (e.g., timing of weaning, pressures and FiO2 delivered) in each phenotype and a comparison among them is needed

Past, Present, and Future of Regulatory T Cell Therapy in Transplantation and Autoimmunity

Regulatory T cells (Tregs) are important for the induction and maintenance of peripheral tolerance therefore, they are key in preventing excessive immune responses and autoimmunity. In the last decades, several reports have been focussed on understanding the biology of Tregs and their mechanisms of action. Preclinical studies have demonstrated the ability of Tregs to delay/prevent graft rejection and to control autoimmune responses following adoptive transfer in vivo. Due to these promising results, Tregs have been extensively studied as a potential new tool for the prevention of graft rejection and/or the treatment of autoimmune diseases. Currently, solid organ transplantation remains the treatment of choice for end-stage organ failure. However, chronic rejection and the ensuing side effects of immunosuppressants represent the main limiting factors for organ acceptance and patient survival. Autoimmune disorders are chronic diseases caused by the breakdown of tolerance against self-antigens. This is triggered either by a numerical or functional Treg defect, or by the resistance of effector T cells to suppression. In this scenario, patients receiving high doses of immunosuppressant are left susceptible to life-threatening opportunistic infections and have increased risk of malignancies. In the last 10 years, a few phase I clinical trials aiming to investigate safety and feasibility of Treg-based therapy have been completed and published, whilst an increasing numbers of trials are still ongoing. The first results showed safety and feasibility of Treg therapy and phase II clinical trials are already enrolling. In this review, we describe our understanding of Tregs focussing primarily on their ontogenesis, mechanisms of action and methods used in the clinic for isolation and expansion. Furthermore, we will describe the ongoing studies and the results from the first clinical trials with Tregs in the setting of solid organ transplantation and autoimmune disorders. Finally, we will discuss strategies to further improve the success of Treg therapy

New Insights in Abdominal Pain in Paroxysmal Nocturnal Hemoglobinuria (PNH): A MRI Study.

Abdominal pain in PNH has never been investigated by in-vivo imaging studies. With MRI, we aimed to assess mesenteric vessels flow and small bowel wall perfusion to investigate the ischemic origin of abdominal pain.Six PNH patients with (AP) and six without (NOP) abdominal pain underwent MRI. In a blinded fashion, mean flow (MF, quantity of blood moving through a vessel within a second, in mL·s-1) and stroke volume (SV, volume of blood pumped out at each heart contraction, in mL) of Superior Mesenteric Vein (SMV) and Artery (SMA), areas under the curve at 60 (AUC60) and 90 seconds (AUC90) and Ktrans were assessed by two operators.Mean total perfusion and flow parameters were lower in AP than in NOP group. AUC60: 84.81 ± 11.75 vs. 131.73 ± 18.89 (P < 0.001); AUC90: 102.33 ± 14.16 vs. 152.58 ± 22.70 (P < 0.001); Ktrans: 0.0346 min-1 ± 0.0019 vs. 0.0521 ± 0.0015 (P = 0.093 duodenum, 0.009 jejunum/ileum). SMV: MF 4.67 ml/s ± 0.85 vs. 8.32 ± 2.14 (P = 0.002); SV 3.85 ml ± 0.76 vs. 6.55 ± 1.57 (P = 0.02). SMA: MF 6.95 ± 2.61 vs. 11.2 ± 2.32 (P = 0.07); SV 6.52 ± 2.19 vs. 8.78 ± 1.63 (P = 0.07). We found a significant correlation between MF and SV of SMV and AUC60 (MF:ρ = 0.88, P < 0.001; SV: ρ = 0.644, P = 0.024), AUC90 (MF: ρ = 0.874, P < 0.001; SV:ρ = 0.774, P = 0.003) and Ktrans (MF:ρ = 0.734, P = 0.007; SV:ρ = 0.581, P = 0.047).Perfusion and flow MRI findings suggest that the impairment of small bowel blood supply is significantly associated with abdominal pain in PNH

Spearman rank correlation analysis.

<p>Correlation between MRI perfusion parameters (on the horizontal axis)—AUC₆₀ (A), AUC₉₀ (B), and K^trans (C)—in the whole small bowel—of PNH patients and SV of SMV (on the vertical axis).</p

Assessment of small bowel wall perfusion.

<p>To calculate MRI perfusion parameters, AUC₆₀, AUC₉₀ and K^trans, elliptic ROIs were positioned in different segments of the small bowel wall, particularly on proximal and distal jejunum and proximal, middle and distal ileum, as showed in this figure.</p

Results.

<p>AUC₆₀ indicates area under the curve at 60 s after contrast agent injection; AUC₉₀, area under the curve at 90 s after contrast agent injection; SMV, superior mesenteric vein; SMA, superior mesenteric artery.</p><p>Results.</p

MF and SV in the mesenteric venous (SMV) and arterial (SMA) compartment.

<p>The horizontal axis represents the PNH patients without (0) and with (1) abdominal pain; the vertical axis represents the MF and SV values on superior mesenteric vein (SMV, dark blue) and artery (SMA, light blue). *: <i>P</i><.05; **: <i>P</i><.01; Errors bars: 95% of confidence interval.</p