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The diagnosis of coronavirus disease 2019 (COVID-19) is mainly based on a positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) result. PCR samples are obtained from upper or lower respiratory tract specimens. However, the sensitivity of PCR is known to have some limitations. We report on a patient who was admitted to our hospital with dyspnea, fever, cough, and history of contact with a SARS-CoV-2 infected relative. The initial chest computed tomography (CT) showed only minimal changes and SARS-CoV-2 PCR from a nasopharyngeal swab sample was negative. PCR results obtained from further nasopharyngeal swabs, qualified sputum samples, and from a lower respiratory tract specimen also remained negative. At day 13 after admission, a second chest CT showed radiological findings suspicious for viral pneumonia. Finally, serologic results showed high levels of immunoglobulin G and immunoglobulin A antibodies against the S1 domain of the SARS-CoV-2 spike protein, and the patient was diagnosed with COVID-19 pneumonia.

Cell activation and apoptosis lead to the formation of extracellular vesicles (EVs) such as exosomes or microvesicles (MVs). EVs have been shown to modulate immune responses; recently, MVs were described to carry microRNA (miRNA) and a role for MVs in the pathogenesis of autoimmune diseases has been discussed. Here we systematically characterized MVs and exosomes according to their release stimuli. The miRNA content of viable or apoptotic human T lymphocytes and the corresponding MVs was analyzed. miRNA, protein and surface marker expression, as well as cytokine release by human monocytes was measured after EV engulfment. Finally, miRNA expression in T lymphocytes and MVs of healthy individuals was compared with those of systemic lupus erythematosus (SLE) patients. We demonstrate that, depending on the stimuli, distinct subtypes of EVs are released, differing in size and carrying a specific RNA profile. We observed an accumulation of distinct miRNAs in MVs after induction of apoptosis and the transfer of functional miRNA by MVs into human monocytes. MVs released from apoptotic cells provoke less of an inflammatory response than those released from viable cells. MiR-155*, miR-34b and miR-34a levels in T lymphocytes and corresponding MVs were deregulated in SLE when compared to healthy individuals.

The large collection of howardite-eucrite-diogenite (HED) meteorites allows us to study the initial magmatic differentiation of a planetesimal. We report Pb-Pb ages of the unequilibrated North West Africa (NWA) 4215 and Dhofar 700 diogenite meteorites and their mass-independent 26Mg isotope compositions (26Mg*) to better understand the timing of differentiation and crystallization of their source reservoir(s). NWA 4215 defines a Pb-Pb age of 4484.5 ± 7.9 Myr and has a 26Mg* excess of +2.3 ± 1.6 ppm whereas Dhofar 700 has a Pb-Pb age of 4546.4 ± 4.7 Myr and a 26Mg* excess of +25.5 ± 1.9 ppm. We interpret the young age of NWA 4215 as a thermal overprint, but the age of Dhofar 700 is interpreted to represent a primary crystallization age. Combining our new data with published Mg isotope and trace element data suggests that approximately half of the diogenites for which such data are available crystallized within the first 1–2 Myr of our solar system, consistent with a short-lived, early-formed magma ocean undergoing convective cooling. The other half of the diogenites, including both NWA 4215 and Dhofar 700, are best explained by their crystallization in slowly cooled isolated magma chambers lasting over at least ~20 Myr.

We report on mineralogy, petrography, and whole-rock 26 Al- 26 Mg systematics of eight amoeboid olivine aggregates (AOAs) from the oxidized CV chondrite Allende. The AOAs consist of forsteritic olivine, opaque nodules, and variable amounts of Ca,Al-rich inclusions (CAIs) of different types, and show evidence for alteration to varying degrees. Melilite and anorthite are replaced by nepheline, sodalite, and grossular; spinel is enriched in FeO; opaque nodules are replaced by Fe,Ni-sulfides, ferroan olivine and Ca,Fe-rich pyroxenes; forsteritic olivine is enriched in FeO and often overgrown by ferroan olivine. The AOAs are surrounded by fine-grained, matrix-like rims composed mainly of ferroan olivine and by a discontinuous layer of Ca,Fe-rich silicates. These observations indicate that AOAs experienced in situ elemental open-system iron-alkali- halogen metasomatic alteration during which Fe, Na, Cl, and Si were introduced, whereas Ca was removed from AOAs and used to form the Ca,Fe-rich silicate rims around AOAs. The whole-rock 26 Al- 26 Mg systematics of the Allende AOAs plot above the isochron of the whole-rock Allende CAIs with a slope of (5.23 ± 0.13) · 10 )5 reported by Jacobsen et al. (2008). In contrast, whole-rock 26 Al- 26 Mg isotope systematics of CAIs and AOAs from the reduced CV chondrite Efremovka define a single isochron with a slope of (5.25± 0.01) · 10 )5 (Larsen et al. 2011). We infer that the excesses in 26 Mg* present in Allende AOAs are due to their late-stage open-system metasomatic alteration. Thus, the 26 Al- 26 Mg isotope systematics of Allende CAIs and AOAs are disturbed by parent body alteration processes, and may not be suitable for high-precision chronology of the early solar system events and processes.

Antibody-based approaches have become a novel treatment modality for lymphoma patients. Humanized 1D10 (Hu1D10; Remitogen) is among the antibodies that are currently under evaluation in phase II clinical trials in lymphoma patients. The 1D10 antibody is directed against a polymorphic epitope on the beta-chain of human leucocyte antigen (HLA) class II. We found expression of the 1D10 epitope on B cells and monocytes from approximately 50% of healthy donors. Analyses of 1D10 expression on malignant cells revealed that approximately half of the HLA class II-positive haematological malignancies expressed the 1D10 epitope. In whole blood antibody-dependent cellular cytotoxicity (ADCC) assays, Hu1D10 was more effective than rituxan in killing malignant ARH-77 B cells. Interestingly, Hu1D10-mediated lymphoma cell lysis was significantly enhanced when blood from granulocyte colony-stimulating factor (G-CSF)-treated patients was compared with blood from healthy controls. Analyses of the relevant effector cell populations revealed that FcgammaRI (CD64)-positive polymorphonuclear cells were critical for enhanced Hu1D10-mediated lymphoma killing during G-CSF therapy, while the same effector cell population induced only marginal lysis with rituxan. Furthermore, Hu1D10 was highly effective in inducing apoptosis in primary lymphoma cells from B chronic lymphocytic leukaemia patients. These preclinical results form the basis for a phase I/II clinical trial of Hu1D10 in combination with G-CSF.