Objectives Intravenous immunoglobulin (IVIG) therapy is effective against some autoimmune diseases. Although its efficacy on peripheral neuropathy due to eosinophilic granulomatosis with polyangiitis-one of myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA)-associated vasculitis (MPO-AAV)-has been established, that on other MPO-AAV remains undetermined. We examined the effects of pharmaceutical immunoglobulins on the formation of neutrophil extracellular traps (NETs) related to MPO-ANCA production and the development of MPO-AAV.Methods Peripheral blood neutrophils from healthy volunteers were pretreated with 5 mg/ml human sulfo-immunoglobulins (IVIG-S) and then exposed to 100 nM phorbol myristate acetate (PMA). Thereafter, neutrophils were stained with SYTOX Green and then subjected to flow cytometry. Next, Wistar-Kyoto rats were given oral administration of 10 mg/kg/day propylthiouracil for 28 days and intraperitoneal (i.p.) injection of 1 µg PMA on days 0 and 7. These rats were divided into two groups: Group 1 with i.p. injection of 400 mg/kg IVIG-S on days 8-12 and Group 2 with i.p. injection of vehicle similarly. ANCA titers were chronologically determined by indirect immunofluorescence. On day 28, all rats were killed to examine NET formation in the peritoneum and the development of AAV.Results IVIG-S significantly inhibited NET formation induced by PMA in vitro. NET amounts in the peritoneum in Group 1 were significantly smaller than in Group 2, and ANCA titers in Group 1 were significantly lower than in Group 2. The degree of pulmonary hemorrhage in Group 1 was also smaller than in Group 2. ConclusionPharmaceutical immunoglobulins reduce NET formation and ameliorate the development of MPO-AAV.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a single-stranded RNA virus that causes coronavirus disease 2019, which spread worldwide immediately after the first patient infected with this virus was discovered in Wuhan, China, in December 2019. Currently, polymerase chain reaction (PCR) specimens for the detection of SARS-CoV-2 include saliva, nasopharyngeal swabs, and lower respiratory tract-derived materials such as sputum. Initially, nasopharyngeal swab specimens were applied mainly to the PCR detection of SARS-CoV-2. There was a risk of infection to healthcare workers due to coughing or sneezing by the subjects at the time of sample collection. In contrast, saliva specimens have a low risk of droplet infection and are easy to collect, and their application to PCR testing has been promoted. In this study, we have determined the detection limit of SARS-CoV-2 in saliva samples and examined the effects of storage temperature and storage time of saliva samples on the PCR detection results. As a result, 5 × 10 3 copies of SARS-CoV-2 could be detected in 1 mL phosphate-buffered saline, whereas 5 × 10 4 copies of SARS-CoV-2 were needed in 1 mL saliva to detect the virus by real-time one-step PCR. Interestingly, SARS-CoV-2 (5 × 10 3 copies/mL) could be detected in saliva supplemented with an RNase inhibitor. Concerning the saliva samples supplemented with an RNase inhibitor, the optimal temperature for sample storage was -20 °C, and PCR detection was maintained within 48 h without problems under these conditions. These finding suggest that RNase in the saliva can affect the detection of SARS-CoV-2 by PCR using saliva samples.

NKT cells are defined as T cells that recognize hydrophobic antigens presented by class I MHC-like molecules, including CD1d. Among CD1d-restricted NKT cells, type I and type II subsets have been noted. CD1d-restricted type I NKT cells are regarded as proinflammatory cells in general. On the contrary, accumulated evidence has demonstrated an anti-inflammatory property of CD1d-restricted type II NKT cells. In our earlier study using a rat model with vasculitis, we demonstrated the pro-inflammatory function of CD1d-restricted type II NKT cells and identified that one such cell recognized P 518-532 of rat sterol carrier protein 2 (rSCP2 518-532 ), which appeared on vascular endothelial cells presented by CD1d. Based on this evidence, we attempted to detect human CD1d-restricted type II NKT cells in peripheral blood using hSCP2 518-532 , the human counterpart of rSCP2 518-532, together with a CD1d tetramer in flow cytometry. First, we determined the binding of hSCP2 518-532 to CD1d. Next, we detected CD3-positive hSCP2 518-532 -loaded CD1d (hSCP2 518-532 /CD1d) tetramer-binding cells in peripheral blood of healthy donors. The abundance of TGF-β-producing cells rather than TNF-α-producing cells in CD3-positive hSCP2 518-532 /CD1d tetramer-binding cells suggests the anti-inflammatory property of SCP2-loaded CD1d (SCP2/CD1d) tetramer-binding type II NKT cells in healthy individuals. Furthermore, we compared cytokine profile between healthy individuals and patients with vasculitis in a pilot study. Interestingly, the percentage of TGF-β-producing cells in SCP2/CD1d tetramerbinding type II NKT cells in vasculitic patients was significantly lower than that in healthy controls despite the greater number of these cells. Although further studies to clarify the mechanism and significance of this phenomenon are needed, SCP2/CD1d tetramer-binding type II NKT cells in peripheral blood should be examined in more detail to understand the pathophysiology of vasculitides in humans.

Severe coronavirus disease 2019 (COVID‐19) is characterized by acute respiratory distress syndrome and multiple organ dysfunction, in which the host immune response plays a pivotal role. Excessive neutrophil activation and subsequent superfluity of neutrophil extracellular traps (NETs) can lead to tissue damage, and several studies have shown the involvement of neutrophils in severe COVID‐19. However, the detailed responses of each neutrophil subset to SARS‐CoV‐2 infection has not been fully described. To explore this issue, we incubated normal‐density granulocytes (NDGs) and low‐density granulocytes (LDGs) with different viral titers of SARS‐CoV‐2. NDGs form NETs with chromatin fibers in response to SARS‐CoV‐2, whereas LDGs incubated with SARS‐CoV‐2 display a distinct morphology with condensed nuclei and moderate transcriptional changes. Based on these transcriptional changes, we suggest that AGO2 possibly plays a role in LDG regulation in response to SARS‐CoV‐2.

No abstract

Keywords:! ! ! !

Background: Patients and Methods: Results: Conclusion:

Background: Methods: Results: Conclusion: