Complement activation induces excessive T cell cytotoxicity in severe COVID-19

Severe COVID-19 is linked to both dysfunctional immune response and unrestrained immunopathology, and it remains unclear whether T cells contribute to disease pathology. Here, we combined single-cell transcriptomics and single-cell proteomics with mechanistic studies to assess pathogenic T cell functions and inducing signals. We identified highly activated CD16+ T cells with increased cytotoxic functions in severe COVID-19. CD16 expression enabled immune-complex-mediated, T cell receptor-independent degranulation and cytotoxicity not found in other diseases. CD16+ T cells from COVID-19 patients promoted microvascular endothelial cell injury and release of neutrophil and monocyte chemoattractants. CD16+ T cell clones persisted beyond acute disease maintaining their cytotoxic phenotype. Increased generation of C3a in severe COVID-19 induced activated CD16+ cytotoxic T cells. Proportions of activated CD16+ T cells and plasma levels of complement proteins upstream of C3a were associated with fatal outcome of COVID-19, supporting a pathological role of exacerbated cytotoxicity and complement activation in COVID-19.

Hepatitis B and C virus infection in Romanian non-Hodgkin's lymphoma patients

We determined the hepatitis C virus (HCV) antibodies (anti-HCV) and the hepatitis B virus (HBV) surface antigen (HBsAg) in a cohort of 68 consecutive non-Hodgkin's lymphoma (NHL) patients diagnosed and treated in our institution between December 1997 and March 1999. 27 cases were diagnosed as low-grade, 33 as intermediate-grade, and eight as high-grade NHL. In 35 cases (51.4%) we found evidence of either HCV or HBV infection. Anti-HCV antibodies were found in 20 patients (29.5%) and HBsAg was found in 21 patients (30.8%). In six patients both anti-HCV and HBsAg were present. Anti-HCV were present in 12/27 low-grade NHL cases (44.4%) and in 8/41 intermediate/high-grade (aggressive) NHL cases (19.5%, P < 0.03). HBsAg was found in 10/27 low-grade NHL cases (37%) and in 11/41 aggressive NHL cases (26.8%). Evidence of liver disease, as reflected by elevated aminotransferases or typical alterations at liver biopsy, was present in eight patients. Cryoglobulins were present in six patients, all anti-HCV positive and with low-grade NHL. The prevalence of both HCV antibodies and HBsAg was significantly higher (P < 0.0001) in our NHL cases than in a sample of the general Romanian population, where the prevalence of anti-HCV was 4.9% and that of HBsAg was 6.3%. It is difficult to say whether either HCV or HBV had actually been involved in lymphomagenesis or if alpha-interferon treatment would be effective in this subset of patients.

Expression of estrogen receptor sub-types alpha and beta in acute and chronic cardiac allograft vasculopathy

BACKGROUND

The vasculoprotective effects of estrogen are well-established not only in women with age-related atherosclerosis, but also after experimental vascular injury and in chronic allograft vasculopathy. Evidence exists that the newly discovered estrogen receptor (ER) beta, rather than the classical ERalpha is related to the vasculoprotective effect. Here we investigate whether and to what extent the two ERs are expressed in cardiac allografts in the rat and human in native state and during acute and chronic rejection.

METHODS

Rat cardiac allografts were performed from male DA (AG-B4, RT1(a)) to male WF (AG-B2, RT1(v)) strain and syngeneic transplants from DA to DA strain; human male-to-male heart allograft endomyocardial biopsies came from our biopsy files.

RESULTS

Under in situ hybridization, ERbeta mRNA was prominently expressed in rat vessels and stroma, whereas ERalpha mRNA was present in low levels only. In immunohistochemistry, 2 ERbeta-specific antibodies stained rat and human vessels and stroma, whereas only a weak or no signal was obtained with 2 ERalpha-specific antibodies. Interestingly, the mRNA and protein expression levels in the rat carried only a weak correlation with the intensity of acute rejection, i.e., was not related to the intensity of inflammation.

CONCLUSIONS

Our results demonstrate that ERbeta is the predominant ER in rat and human cardiac allografts, and suggest that, unless additional ERs are identified, the vasculoprotective effects of estrogen derivatives in cardiac allograft vasculopathy are mediated by ERbeta rather than by the classical ERalpha.

CD4+ T cell calibration of antigen-presenting cells optimizes antiviral CD8+ T cell immunity

Antiviral CD8+ T cell immunity depends on the integration of various contextual cues, but how antigen-presenting cells (APCs) consolidate these signals for decoding by T cells remains unclear. Here, we describe gradual interferon-α/interferon-β (IFNα/β)-induced transcriptional adaptations that endow APCs with the capacity to rapidly activate the transcriptional regulators p65, IRF1 and FOS after CD4+ T cell-mediated CD40 stimulation. While these responses operate through broadly used signaling components, they induce a unique set of co-stimulatory molecules and soluble mediators that cannot be elicited by IFNα/β or CD40 alone. These responses are critical for the acquisition of antiviral CD8+ T cell effector function, and their activity in APCs from individuals infected with severe acute respiratory syndrome coronavirus 2 correlates with milder disease. These observations uncover a sequential integration process whereby APCs rely on CD4+ T cells to select the innate circuits that guide antiviral CD8+ T cell responses.

Fourier transform infrared spectroscopic study of surface acidity by pyridine adsorption on Mo/ZrO2-SiO2(Al2O3) catalysts

Acidity of the oxidic molybdenum catalysts supported on mixed ZrO2-SiO2 and ZrO2-Al2O3 carriers was investigated by Fourier transform infrared spectroscopy of pyridine adsorption. Deposition of molybdenum on ZrO2-SiO2 and ZrO2-Al2O3 supports leads to formation of surface Brønsted acid sites. The number of the Brønsted and Lewis acid sites in supported-molybdenum catalysts depends on both the ZrO2 content and the type of the support. With increasing ZrO2 content, the Lewis acid sites increase for both series of catalysts. The Brønsted acid sites are higher for Mo/ZrO2-SiO2 samples compared to those for Mo/ZrO2-Al2O3 and also increase with zirconia.

An infrared study of CO adsorption on silica-supported Ru-Sn catalysts

CO adsorption on Ru-Sn/SiO(2) catalysts of various Sn/(Ru+Sn) ratios was examined by Diffuse Reflectance Infrared Fourier-Transform Spectroscopy (DRIFTS). The catalysts were prepared by the incipient wetness impregnation method. Catalysts were activated by H(2) reduction at 773 K. CO adsorbed on the catalysts shows spectra whose band frequencies are divided into three groups: (i) High Frequency Region (HFR), containing a band at 2065 cm(-1), (ii) Low Frequency Region 1 (LFR(1)), containing bands at 2040-2015 cm(-1), (iii) Low Frequency Region 2 (LFR(2)), containing bands at 1990 and 1945 cm(-1). The types of adsorbed CO species formed strongly depend on the ratio Sn/(Ru+Sn) in the catalyst, CO pressure and temperature of adsorption. Adsorption of CO on Ru sites in the Ru/SiO(2) catalyst results in LFR(1) bands at 2040-2015 cm(-1), which are independent of the CO pressure but the adsorption complexes are easily destroyed by raising the temperature. The addition of Sn to the catalyst creates new sites for CO adsorption. After adsorption at 298 K, the HFR band at 2065 cm(-1) and LFR(2) bands at 1990-1950 cm(-1) are observed. The relative intensities of these bands increase with increasing Sn-content in the samples. The LFR bands are thermally stable while the HFR band is not. The formation of the corresponding species is favored by increasing the CO pressure. Adsorbed CO species giving LFR(1) bands are assigned to linearly-adsorbed CO on the Ru(0) and/or on the Ru-Sn alloy sites. Adsorbed CO species giving HFR bands are assigned to CO adsorption on Ru(delta+)-O-Sn sites. After low temperature CO adsorption on samples with high Sn-content, only species that show bands at 1990 and 1945 cm(-1) in LFR(2) are observed.

In vivo effects of amtolmetin guacyl on lipid peroxidation and antioxidant defence systems in different models of gastrointestinal injury

1. The in vivo effects of the non-steroid anti-inflammatory drug (NSAID) amtolmetin guacyl (AMG) on lipid peroxidation (LP) and on antioxidant enzyme and non-enzyme defence systems were investigated in models of stomach and colon damages, induced by other NSAIDs, by ethanol or by 2,4,6-trinitrobenzenesulfonic acid (TNBS). 2. Indomethacin increased LP, glutathione peroxidase (GSH-PX) and glucose-6-phosphate dehydrogenase (Glu-6-P-DH) activities and decreased glutathione levels in gastric mucosa. Pretreatment with AMG normalized some of the parameters affected by indomethacin. 3. Treatment of rats with ethanol for 0.5 h led to a decrease in glutathione levels as well as activities of glutathione reductase and Glu-6-P-DH in gastric mucosa. AMG, administered 0.5 h before ethanol, limited the adverse actions of ethanol. 4. Amtolmetin guacyl failed to abolish the TNBS-induced changes in the followed-up parameters in colon mucosa and liver, but additional alterations (as with tolmetin) were not observed. 5. The beneficial profile of AMG in the various experimental models of free radical-induced damage investigated in this study suggests the possibility that this drug might possess antioxidant activity.

Different cell clones in bone marrow and spleen of a patient with chronic myelocytic leukemia (CML) in blastic phase

The chromosome study of a patient with chronic myelocytic leukemia in blastic phase revealed a 46,XY,Ph1/47,XY,Ph1,+8 cytogenetic constitution in bone marrow cells and a 46,XY,Ph1/48,XY,2Ph1,+19 cytogenetic constitution in spleen cells. As the cell clones exhibiting chromosome abnormalities in addition to the Ph1 chromosome evolved apparently independently, it is suggested that the acute transformation had a bifocal, myeloid and splenic origin.