Differential Functional Responses of Neutrophil Subsets in Severe COVID-19 Patients.

Neutrophils play a significant role in determining disease severity following SARS-CoV-2 infection. Gene and protein expression defines several neutrophil clusters in COVID-19, including the emergence of low density neutrophils (LDN) that are associated with severe disease. The functional capabilities of these neutrophil clusters and correlation with gene and protein expression are unknown. To define host defense and immunosuppressive functions of normal density neutrophils (NDN) and LDN from COVID-19 patients, we recruited 64 patients with severe COVID-19 and 26 healthy donors (HD). Phagocytosis, respiratory burst activity, degranulation, neutrophil extracellular trap (NET) formation, and T-cell suppression in those neutrophil subsets were measured. NDN from severe/critical COVID-19 patients showed evidence of priming with enhanced phagocytosis, respiratory burst activity, and degranulation of secretory vesicles and gelatinase and specific granules, while NET formation was similar to HD NDN. COVID LDN response was impaired except for enhanced NET formation. A subset of COVID LDN with intermediate CD16 expression (CD16Int LDN) promoted T cell proliferation to a level similar to HD NDN, while COVID NDN and the CD16Hi LDN failed to stimulate T-cell activation. All 3 COVID-19 neutrophil populations suppressed stimulation of IFN-γ production, compared to HD NDN. We conclude that NDN and LDN from COVID-19 patients possess complementary functional capabilities that may act cooperatively to determine disease severity. We predict that global neutrophil responses that induce COVID-19 ARDS will vary depending on the proportion of neutrophil subsets.

The effects of wearing corrective lenses for presbyopia on distance vision.

The possibility of patient behaviour concerning the wearing of reading spectacles influencing the magnitude and rate of change in distance vision has been hypothesised but not fully examined. This study examined the changes in distance vision over time of 674 presbyopic patients between the ages of 44 and 69 who came to their eye professional needing reading spectacles. Prior to this study, these patients had never worn spectacles. The majority of patients opted for full-eye (complete) reading spectacles and 150 patients selected bifocals. It was found that patients wearing complete reading spectacles eventually adapted to wearing their reading spectacles for intermediate or distance work. Through X2, it was found that there were significant differences in the reduction of distance visual acuity between groups based on the amount of time spent wearing reading spectacles for intermediate or distance work. The greater the number of hours spent wearing reading spectacles and viewing beyond their focal point, the greater the change in distance visual acuity. It also appeared to affect the degree of change in their prescription. Age was not significantly related.