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Abstract Evidence shows that individuals infected by SARS-CoV-2 experience an altered metabolic state in multiple organs. Metabolic activities are directly involved in modulating immune responses against infectious diseases, yet our understanding of how host metabolism relates to inflammatory responses remains limited. To better elucidate the underlying biochemistry of the leukocyte response, we focused our analysis on possible relationships between SARS-CoV-2 post-infection stages and distinct metabolic pathways. Indeed, we observed a significant altered metabolism of tryptophan and urea cycle pathways in cultures of peripheral blood mononuclear cells obtained 60–90 days after infection and showing in vitro IgG antibody memory for spike-S1 antigen (n = 17). This work, for the first time, identifies metabolic routes in cell metabolism possibly related to later stages of immune defence against SARS-CoV-2 infection, namely, when circulating antibodies may be absent but an antibody memory is present. The results suggest reprogramming of leukocyte metabolism after viral pathogenesis through activation of specific amino acid pathways possibly related to protective immunity against SARS-CoV-2.

SARS-CoV-2 is the virus responsible for the COVID-19 pandemic, causing respiratory syndrome and other manifestations. The clinical consequences of the SARS-CoV-2 infection are highly heterogeneous, ranging from asymptomatic and mild to severe and fatal conditions, with the highest mortality rate reached among elderly people. Such heterogeneity appears strongly influenced by the host immune response, which in turn is profoundly affected by aging. In fact, the occurrence of a low-grade inflammation and a decline in specific immune defense is generally reported in older people. Although the low ability of B cells to provide primary and secondary specific responses with a consequent increase in susceptibility to and severity of virus infections is generally described in elderly people, we would like to present here the particular case of a 100-year-old woman, who recovered well from COVID-19 and developed a long-term memory against SARS-CoV-2. Following the infection, the patient's blood was tested with both a classical ELISA and a specific Cell-ELISA addressed to measure the anti-spike S1 specific IgG released in plasma or produced in vitro by memory B cells, respectively. While showing negative on classical serological testing, the patient's blood was positive in Cell-ELISA up to 1 year after the infection. Our observation highlights a potential mechanism of B cell-dependent, long-term protection in response to SARS-CoV-2 infection, suggesting that in a case of successful aging, the absence of specific antibodies in serum does not necessarily mean the absence of immune memory.

Knowledge of the antibody-mediated immune response to SARS-CoV-2 is crucial to understand virus immunogenicity, establish seroprevalence, and determine whether subjects or recovered patients are at risk for infection/reinfection and would therefore benefit from vaccination. Here, we describe a novel and simple cell-ELISA specifically designed to measure viral spike S1-specific IgG produced in vitro by B cells in peripheral blood mononuclear cell (PBMC) cultures from a cohort of 45 asymptomatic ( n = 24) and symptomatic ( n = 21) individuals, with age ranging from 8 to 99 years. All subjects underwent ELISA serological screening twice, at the same time as the cell-ELISA (T2) as well as 35-60 days earlier (T1). Cryopreserved PBMCs of healthy donors obtained years before the COVID-19 pandemic were also included in the analysis. The preliminary results presented here show that out of 45 tested subjects, 16 individuals (35.5%) were positive to the cell-ELISA, 11 (24.5%) were concomitantly positive in the serological screening (T1 and/or T2), and only one person was exclusively positive in ELISA (T1) and negative in cell-ELISA, though values were close to the cutoff. Of note, five individuals (11.2%) tested negative in ELISA but positive in cell-ELISA and thus, they appear to have circulating B cells that produce antibodies against SARS-CoV-2, likely at levels that are undetectable in the serum, which challenges the negative results of the serological screening. The relative level of in vitro secreted IgG was measurable in positive subjects, ranging from 7 to 50 ng/well. Accordingly, all anti-SARS-CoV-2 antibody-positive subjects previously reported moderate to severe symptoms attributable to COVID-19, even though the RT-PCR data were rarely available to confirm viral infection. Overall, the described cell-ELISA might be an effective method for detecting subjects who encountered the virus in the past, and thus helpful to improve serological ELISA tests in the case of undetectable/equivocal circulating IgG levels, and a suitable and improved tool to better evaluate SARS-CoV-2-specific humoral immunity in the COVID-19 pandemic.

Aim: To report on the use of a combined intra-ocular tamponade with silicone oil and perfluorohexyloctane (F(6)H(8)) in the treatment of complex retinal detachment., Design: A prospective consecutive interventional case series from seven study centres., Participants: 69 patients presenting a retinal detachment with proliferative vitreoretinopathy (PVR) and retinal breaks of the inferior two quadrants of the fundus., Method: Patients were divided into two groups: (1) 28 eyes which had not been operated on before; (2) 41 eyes affected by recurrent retinal detachment that had had unsuccessful previous surgery with silicone oil or gas tamponade. A pars plana vitrectomy, membrane peeling and -- when necessary -- a retinotomy were performed; the vitreous cavity was filled with two thirds of F(6)H(8) and one third of silicone oil 1,000 mPas (double filling, DF). The endotamponade was removed after 30-45 days (median 38) and replaced by balanced salt solution or silicone oil according to the condition of the retina., Results: Retinal reattachment was achieved in 52 out of 69 cases (75%) 6 months after removal of the DF without any endotamponade., Conclusion: The DF with F(6)H(8) and silicone oil allows a good endotamponading to the inferior retina and the posterior pole. The DF appeared to be well tolerated. Further studies are necessary to evaluate whether a DF is advantageous in respect to silicone oil filling alone in case of retinal breaks and PVR of the inferior retina.

Background: A study was carried out to elucidate the anatomical and functional outcome after surgical excision of subfoveal choroidal neovascular membranes in high myopia., Methods: Sixty-five patients with high myopia (> or =6 diopters), well-defined subfoveal neovascular membranes on fluorescein angiography and preoperative visual acuity < or =20/100 were selected for surgery. A standardized surgical technique was used in all cases, by a single surgeon. The main outcomes assessed were Snellen visual acuity, surgical retinal pigment epithelium defect and postoperative perfusion of the choriocapillaris. Multifactor analysis of variance and chi-square/Fisher's exact test statistics were used to assess the association between patients' pre- and postoperative characteristics and outcome measures., Results: Follow-up ranged from 6 to 48 months (mean 16 months). Mean postoperative visual acuity (0.18) was significantly better than mean preoperative visual acuity (0.09). Visual acuity improved by at least two lines in 29 eyes (45%) and was unchanged in 24 (37%). Overall, 43 eyes (66%) had visual acuity of 20/200 or better and 15 (23%), 20/60 or better. Predictive factors with a significant effect on final visual acuity were mean visual acuity, preoperative status of retinal pigment epithelium and postoperative perfusion of the choriocapillaris. Postoperative perfusion was detected in 31 (48%) of the total 65 eyes and in 12 (67%) of the 18 eyes with normal retinal pigment epithelium at baseline. The mean postoperative retinal pigment epithelium defect was 4.6 times larger than the original neovascular membrane. In selected patients, SLO macular scotometry showed areas of retained retinal sensitivity within the atrophic scar., Conclusion: The natural history of subfoveal neovascularization in high myopia is rarely visually restorative. By contrast, surgical excision of the membranes is feasible and may restore visual acuity in selected patients. This therapeutic approach merits a formal multicenter clinical trial.

Purpose: To develop a system for the examination of the ablated surface after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) and to correlate the surface regularity to the functional outcome., Methods: A Nidek Eas-1000 Anterior Eye Segment Analysis System was used to examine the ablated surface or the interface regularity immediately after PRK and LASIK. Eighty eyes were evaluated and divided into three study groups; group 1; regularity (18 eyes), group 2; mild irregularity (32 eyes) group 3; severe irregularity (30 eyes)., Results: At 12 months postoperatively, group 1 (regularity) showed the best percentage of eyes with 0 haze (100%) and with a refraction +/- 1.00 D of plano (89%); group 2 (mild irregularity) 84% had 0 haze and 62% were +/- 1.00 D of plano; group 3 (severe irregularity) 27% had 0 haze and 47% were +/- 1.00 D of plano., Conclusion: The patients with no postoperative irregularity had a sharply lower incidence of haze and a better refractive outcome with respect to plano, confirming the influence of ablation regularity on the results and the importance of this analysis in clinical practice.

Purpose: To assess a new method for decreasing corneal ablated surface irregularities after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) by performing a final smoothing immediately after the treatment., Methods: One hundred forty-seven eyes with ablation irregularities after PRK or LASIK using the Nidek ED-5000 excimer laser and examined with the Nidek EAS 1000, were randomized into two groups: 74 eyes had final smoothing and 73 eyes were patched immediately. Preoperative mean refraction for the smoothing group was -7.55 +/- 2.50 D and for the patched group, it was -7.30 +/- 1.90 D, (p = 0.04)., Results: AT 12 months after treatment, mean haze was 0.5 +/- 0.3 in the smoothing group and 1.2 +/- 0.4 in the patched group (p = 0.006); mean spectacle-corrected visual acuity was 1.1 +/- 0.25 in the smoothing group and 0.95 +/- 0.18 in the patched group (p = 0.02); the percentages of eyes within 1.00 D of the planned correction was 68% in the smoothing group and 33% in the patched group., Conclusion: Performing a final smoothing immediately after PRK or LASIK improves refractive and optical outcomes.

Background: We investigated the functional outcomes of macular surgery for idiopathic, myopic and age-related subfoveal neovascular membranes and looked for preoperative features associated with better final visual acuity (VA)., Methods: We retrospectively studied 61 patients who had undergone macular surgery in our department between October 1992 and September 1994. Follow-up ranged from 5 to 27 months. Of 61 eyes with subfoveal neovascularizations, 6 were idiopathic, 21 had high myopia (-13 D median) and 34 displayed age-related macular degeneration (AMD). Median preoperative VA was 5/200 in AMD, 20/300 in myopia and 20/200 in idiopathic cases., Results: Four of the six eyes with idiopathic subfoveal neovascularization had VA 20/60 or better after a median follow-up of 18 months. Of the 21 eyes with high myopia, 10 (48%) improved and 13 (62%) were 20/200 or greater after a median follow-up of 12 months. Among the 34 eyes with AMD, VA improved in 7 (21%), but only 6 (18%) were 20/200 or better after a median follow-up of 7 months. Overall, complications included five retinal detachments, ten cataracts and an increase in size of the retinal pigment epithelium defect over the neovascular membrane of 2.3 +/- 0.8 times (mean +/- SD) in idiopathic eyes. 5.9 +/- 3.6 times in myopia and 19.5 +/- 12.2 times in AMD. Recurrence rates for idiopathic, myopic and age-related neovascular membranes were 33%, 19% and 18% respectively. Etiology (P = 0.035), initial VA in myopic eyes (P = 0.026) and initial size of the neovascular membranes in AMD (P = 0.025) were preoperative factors with a significant effect on final visual outcome., Conclusions: Surgical excision of subfoveal neovascular membranes yields different functional results depending on the underlying disease. Severe alteration of the retinal pigment epithelium-Bruch's membrane complex may be responsible for the poor visual outcomes in AMD.

Background: Informations are expected from the histopathological study of surgically excised choroidal neovascular membranes (CNMs), particularly in relation to the angiographic aspects of vascular architecture., Methods: Fluorescein and indocyanine green (ICG) angiograms were studied together with the histopathological features of 12 surgically excised subfoveal CNMs in eyes affected by age-related macular degeneration (ARMD)., Results: Instead of the early and delayed diffuse hyperfluorescence secondary to CNMs observed on fluorescein angiography (seven were well defined, five scar evolved), ICG revealed (a) very early hypofluorescence of the membrane bulk over the fluorescence of the outer choroidal vascular bed and (b) late hyperfluorescence gradually increasing and partially defining the border of membranes. CNMs with well-defined hyperfluorescent aspects were characterized by fibrovascular bulk lined on one side by retinal pigment epithelium. Fibrosis reaction predominated over the vascular components in scar-evolved membranes., Conclusions: Fluorescein and ICG angiographic differences in the appearance of CNMs could depend on (a) the morphological structure and size of the CNM (b) its location within the chorioretinal layers and (c) different molecular characteristics of the dyes used.

Background: Four human corneas that had undergone photorefractive keratectomy (PRK) and subsequent penetrating keratoplasty were examined by means of light and electron microscopy in an attempt to detect possible causes for complications after PRK., Methods: Four eyes with a central corneal leukoma resulting from a previous PRK treatment underwent penetrating keratoplasty respectively 3 days, 3 months, 5 months, and 13 months after the refractive procedure. Different excimer laser instruments (Meditec MEL 50, Summit UV200, and VISX 20/20) had been used. The corneal buttons removed were submitted for light microscopy, electron microscopy and immunohistochemistry., Results: An immature (one to two layers, basement membrane anomalies) but continuous epithelium was present even in the 3-day specimen; between six and eight epithelial layers could be seen in the 13-month specimen, which still presented an undulated aspect of the otherwise normal basement membrane. A continuous acellular collagen layer underlying the epithelium of the ablated area was detected in the superficial stroma of all examined corneas. No Descemet's membrane or endothelial alterations could be seen., Conclusions: Despite recovery of a continuous epithelial layer as early as 3 days after PRK, abnormalities of both epithelium and superficial stroma could be detected in all specimens, including the one obtained 13 months after the refractive procedure.

To avoid postoperative "compartmentalization" of the vitreous cavity, which may accelerate the recurrence of proliferative vitreoretinopathy (PVR), and to provide a tamponading effect lasting long enough to allow the formation of a firm chorioretinal adhesion by retinopexy, we managed 11 eyes with giant retinal tears and grade-B PVR with lensectomy, vitrectomy, 5-day internal tamponade with perfluorodecalin (PFD), and postoperative supine positioning until the PFD was removed. Baseline characteristics included myopia (10 eyes; range, 5.00 to 15.00 diopters) and perforating trauma (one eye). All patients underwent PFD/fluid exchange 5 days after surgery. Anatomic attachment of the retina was achieved with two operations (the second one being the removal of the PFD) in 9 (82%) of the 11 eyes (median follow up, 18 months). In eight eyes (73%), there was no evidence of reproliferation; in one (successfully reattached after PFD/fluid exchange), a macular pucker developed. The intraocular PFD used as an internal tamponade appeared to be well tolerated for up to 5 days, as judged by static threshold perimetry in the two patients tested, and by the functional outcomes (64% of the reattached eyes had a final visual acuity of 20/40 or better).

To avoid postoperative "compartmentalization" of the vitreous cavity, which can potentially accelerate the recurrence of proliferative vitreoretinopathy (PVR), 32 eyes of 32 selected patients with complicated retinal detachment were managed with lensectomy, vitrectomy, 5-day internal tamponade with perfluorocarbon liquids (PFCL) and postoperative supine positioning until PFCL removal. Intraoperatively, 19 eyes had grade C3 or greater PVR; 10 eyes exhibited ocular trauma and 6 displayed giant tears. All but 5 patients (PFCL/fluid exchange) underwent PFCL/silicone oil exchange 5 days after surgery. Anatomic attachment of the retina was achieved with one operation in 25 (78%) of the 32 eyes with a median follow-up of 8 months (mean 8.4 months). Of the 20 eyes that underwent silicone oil removal, none redetached. Nineteen eyes (61%) showed no or only mild reproliferation; a macular pucker developed in 50% of the 20 eyes successfully reattached after PFCL/silicone oil exchange and in none of the 5 eyes successfully reattached after PFCL/fluid exchange. Intraocular tolerance of PFCL for up to 5 days of internal tamponade appeared to be good as judged by static threshold perimetry in the two patients tested and by our functional outcomes, with 88% of the reattached eyes showing a final visual acuity of 5/200 or better.

We evaluated the use of simultaneous double filling with polydimethylsiloxane (PDMS) and fluorosilicone (FSiO) in the repair of complicated retinal detachment in 12 selected cases. Initial retinal reattachment was achieved in all cases. Proliferative vitreoretinopathy (PVR) recurred in 10 patients (83%), 6 of which showed partial retinal detachment. Inferior and superior postoperative residual free spaces were abolished by this procedure, but a new residual fluid space was created, lying horizontally between the bubbles and expanding in a triangular shape nasally to the optic disk and temporally to the macula. Overall, 9 of 10 eyes with postoperative PVR had proliferation involving these areas. These findings support the concept that 'compartmentalization' is of major importance in determining postoperative cell proliferation.

To determine whether the residual free spaces within the vitreous chamber that result after vitreoretinal surgery and internal tamponade may be avoided, and to verify whether such compartmentalization is of real importance in the recurrence of postoperative proliferative vitreoretinopathy (PVR), the use of simultaneous double filling with polydimethylsiloxane (PDMS) and fluorosilicone (FSiO) in the repair of complicated retinal detachment is evaluated in 12 selected cases. Initial retinal reattachment was achieved in all cases. PVR recurred in 10 patients (83%), 6 of whom showed partial retinal detachment. Inferior and superior postoperative residual free spaces were abolished by this procedure, but a new residual fluid space was created, lying horizontally between the bubbles and expanding in a triangular shape nasal to the optic disc and temporal to the macula. Overall, 9 of 10 eyes with PVR after surgery had proliferation involving these areas. These findings support the concept that compartmentalization is of major importance in determining postoperative cell proliferation.

The efficacy, tolerability and safety of low doses (5-7 mg/kg/day) of oral ciclosporin (CS) for treatment of endogenous uveitis resistant to conventional therapy were studied in an open, noncontrolled, multicenter long-term trial. CS was shown to be effective for patients with posterior or intermediate noninfectious uveitis; it limited the progression of the disease, decreased the number and severity of inflammatory relapses, and improved visual acuity while reducing signs of intraocular inflammation. Moreover, in corticodependent patients, a steroid-sparing effect was also obtained. At low doses and by means of the careful monitoring of safety parameters, the side effects (especially renal function impairment) were well controlled. Efficacy was maintained during long-term treatment.

Monoamine oxidase (MAO, E.C. 1.4.3.4) activity was determined by spectrophotofluorimetric assay of the reaction product of the artificial substrate kynuramine in platelets from venous blood samples from 50 outpatients with glaucomas and 47 sex- and age-matched controls. No significant differences were found between MAO activity in control subjects and that in subjects with glaucomas grouped according to diagnostic subcategories. Irrespective of ocular disease, women had significantly higher enzyme activity than men. Age-related changes in platelet MAO were inconsistent.