Association of interleukin-6 and CD4+ T cells and two-week prognosis of patients with COVID-19: a predictive role.

OBJECTIVE: The aim of this study was to determine the association of inflammation and immune responses with the outcomes of patients at various stages, and to develop risk stratification for improving clinical practice and reducing mortality. PATIENTS AND METHODS: We included 77 patients with primary outcomes of either death or survival. Demographics, clinical features, comorbidities, and laboratory tests were compared. Linear, logistic, and Cox regression analyses were performed to determine prognostic factors. RESULTS: The average age was 59 years (35-87 years). There were 12 moderate cases (16.2%), 42 severe cases (54.5%), and 23 critical cases (29.9%); and 41 were male (53.2%). Until March 20, 68 cases were discharged (88.3%), and nine critically ill males (11.7%) died. Interleukin-6 (IL-6) levels on the 1st day were compared with IL-6 values on the 14th day in the severe and the critically ill surviving patients (F=4.90, p=0.034, ß=0.35, 95% CI: 0.00-0.10), and predicted death in the critically ill patients (p=0.028, ß=0.05, OR: 1.05, 95% CI: 1.01-1.10). CD4+ T-cell counts at admission decreased the hazard ratio of death (p=0.039, ß=-0.01, hazard ratio=0.99, 95% CI: 0.98-1.00, and median survival time 13.5 days). CONCLUSIONS: The present study demonstrated that IL-6 levels and CD4+ T-cell count at admission played key roles of predictors in the prognosis, especially for critically ill patients. High levels of IL-6 and impaired CD4+t cells are seen in severe and critically ill patients with COVID-19.

Levels of peripheral IL-6 and CD4+ and CD8+ T cells and their prognostic significance in COVID-19.

OBJECTIVE: The aim of this study was to discuss the prognostic significance of peripheral interleukin-6 (IL-6) and CD4+ and CD8+ T cells in COVID-19. PATIENTS AND METHODS: Eighty-four COVID-19 patients were retrospectively analyzed and classified into three groups, including the moderate group (15 cases), the serious group (45 cases), and the critical group (24 cases). The levels of peripheral IL-6, CD4+, and CD8+ T cells and CD4+/CD8+ were determined for each group. It was assessed whether these indicators were correlated to the prognosis and death risks of COVID-19 patients. RESULTS: The three groups of COVID-19 patients differed significantly in the levels of peripheral IL-6 and CD4+ and CD8+ cells. The IL-6 levels in the critical, moderate, and serious groups were increased successively, but the changed levels of CD4+ and CD8+ T cells were just opposite to that of IL-6 (p<0.05). The peripheral IL-6 level increased dramatically in the death group, while the levels of CD4+ and CD8+ T cells decreased significantly (p<0.05). The peripheral IL-6 level was significantly correlated with the level of CD8+ T cells and CD4+/CD8+ ratio in the critical group (p<0.05). The logistic regression analysis indicated a dramatic increase in the peripheral IL-6 level in the death group (p=0.025). CONCLUSIONS: The aggressiveness and survival of COVID-19 were highly correlated with the increases in IL-6 and CD4+/CD8+ T cells. The fatalities of COVID-19 individuals remained at increased incidence due to elevated peripheral IL-6 levels.

pH-responsive nanoaggregation of diblock phosphorylcholine copolymers.

We have characterized three diblock copolymers bearing zwitterionic phosphorylcholine and weak tertiary amine groups, namely, poly[((2-(methacryloyloxy)ethyl)phosphorylcholine)30- block-(2-(dimethylamino)ethyl methacrylate)60] (denoted as MPC30-DMA60, Mn=18,000), poly[((2-(methacryloyloxy)ethyl)phosphorylcholine)30- block-(2-(diethylamino)ethyl methacrylate)60) (denoted as MPC30-DEA60, Mn=20,000), and poly[((2-(methacryloyloxy)ethyl)phosphorylcholine)30- block-(2-(diisopropylamino)ethyl methacrylate)60) (denoted as MPC30-DPA60, Mn=21,000), by studying their surface tension and solution aggregation through a combined approach of surface tension measurement, dynamic light scattering, and small-angle neutron scattering. Our results show that larger tertiary amine substituents lead to an increasing tendency to form micellar aggregates, which is consistent with the increasing copolymer hydrophobicity. Thus, MPC30-DMA60 did not aggregate under the experimental conditions studied. The free chains exist in the form of thin cylinders, whose length decreases with copolymer concentration and solution temperature but increases with solution pH. The diameters of the MPC30-DMA60 cylinders remained almost constant at around 30 A under all the conditions studied. At the lower copolymer concentration of 0.5 wt %, the cylindrical lengths correspond to the persistence length of the copolymer backbone and are close to its full length, indicating a rather high rigidity. Further data analysis showed that, at the two higher concentrations of 2 and 4 wt %, the phosphorylcholine and amine blocks associate, inducing bending of the copolymer backbone. One backbone kink was required to satisfy all the constraints, including the dry volume of the copolymer. MPC30-DEA60 showed a similar trend of pH- and concentration-dependent conformational responses for the free copolymer, but in addition micellar aggregation occurred at pH 9. In contrast, MPC30-DPA60 exhibited significantly reduced solubility associated with strong aggregation, which is consistent with it being the most hydrophobic copolymer in the series.

Neutron reflection study of a water-soluble biocompatible diblock copolymer adsorbed at the air/water interface: the effects of pH and polymer concentration.

The effect of varying both the solution pH and copolymer concentration on the structure of layers of poly[2-(methacryloyloxy)ethyl phosphorylcholine-block-2-(dimethylamino)ethyl methacrylate] copolymer (denoted as MPC(30)-DMA(60), M(n) = 18,000) adsorbed at the air/water interface is studied using surface tension and specular neutron reflection. The surface structure of the adsorbed diblock copolymer is represented by a dense layer of 10-15 A on the air side, accompanied by a loose layer of 20-30 A extending into the aqueous phase. Although the uniform layer model generally provided a reasonable description of the adsorbed copolymer chains, some deviations were observed. A more detailed analysis showed that the distribution of the copolymer across the interface required a minimum of three layers to take into account the structural inhomogeneities. Refinement of the structural distributions involved the combined fitting of partially deuterated copolymer in null reflecting water and D(2)O and the fully hydrogenated copolymer in D(2)O, leading to a substantial improvement in the reliability of the structural profiles obtained. The data analysis showed an increase in surface excess at higher copolymer concentrations and at more alkaline pH. However, the copolymer layer was fully immersed in water under all conditions studied. Because the surface excess showed a steady increase across the cmc over the high pH range, we speculate that copolymer adsorption above the cmc involves the formation of surface micellar aggregates under these conditions.