Role of macrophage sialoadhesin in host defense against the sialylated pathogen group B <em>Streptococcus</em>

ABSTRACT: Several bacterial pathogens decorate their surfaces with sialic acid (Sia) residues within cell wall components or capsular exopolysaccharides. Sialic acid expression can promote bacterial virulence by blocking complement activation or by engagement of inhibitory sialic acid-binding immunoglobulin-like lectins (Siglecs) on host leukocytes. Expressed at high levels on splenic and lymph node macrophages, sialoadhesin (Sn) is a unique Siglec with an elongated structure that lacks intracellular signaling motifs. Sialoadhesin allows macrophage to engage certain sialylated pathogens and stimulate inflammatory responses, but the in vivo significance of sialoadhesin in infection has not been shown. We demonstrate that macrophages phagocytose the sialylated pathogen group B Streptococcus (GBS) and increase bactericidal activity via sialoadhesin-sialic-acid-mediated recognition. Sialoadhesin expression on marginal zone metallophillic macrophages in the spleen trapped circulating GBS and restricted the spread of the GBS to distant organs, reducing mortality. Specific IgM antibody responses to GBS challenge were also impaired in sialoadhesin-deficient mice. Thus, sialoadhesin represents a key bridge to orchestrate innate and adaptive immune defenses against invasive sialylated bacterial pathogens. KEY MESSAGE: Sialoadhesin is critical for macrophages to phagocytose and clear GBS. Increased GBS organ dissemination in the sialoadhesin-deficient mice. Reduced anti-GBS IgM production in the sialoadhesin-deficient mice. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00109-014-1157-y) contains supplementary material, which is available to authorized users

The incidence of rhegmatogenous retinal detachment in the Netherlands: Dutch Rhegmatogenous Retinal Detachment Study Group

Objective: To estimate the incidence and characteristics of rhegmatogenous retinal detachment (RRD) in The Netherlands in 2009. Design: Retrospective, observational case series. Participants: All patients with RRD in the Dutch population in 2009. Methods: By reviewing surgical logs, cases of primary RRD repair in 2009 were identified. Exclusion criteria included RRD before 2009 and exudative, tractional, or traumatic retinal detachments. Patient demographics, date of surgery, and lens status were documented. Incidence of RRD and 95% confidence intervals (CIs) were calculated based on the Poisson distribution. Age distribution, male-to-female ratio, and proportion of RRD patients with prior cataract extraction (CE) were determined. A Student t test was used to examine differences in the incidence of RRD between groups. Main Outcome Measures: Annual RRD incidence in the population and per gender-adjusted age category and proportion of RRD patients with prior CE. Results: The annual RRD incidence was 18.2 per 100 000 people (95% CI, 11.4–18.8), with a peak incidence of 52.5 per 100 000 people (95% CI, 29.4–56.8) between 55 and 59 years of age. The Bilateral RRD rate was 1.67%. Macula-off presentation occurred in 54.5% of all RRD patients. Prior CE was noted in 33.5% of RRD eyes. The male-to-female ratio was 1.3:1, and RRD incidence was statistically significantly more frequent in males (P 0.0001). Conclusions: Rhegmatogenous retinal detachment is predominantly a disease of the population older than 50 years, and males are more susceptible to RRD. The annual RRD incidence is highly dependent on demographic characteristics

Strategy for the management of complex retinal detachments: the European vitreo-retinal society retinal detachment study report 2

OBJECTIVE: To study the outcome of the treatment of complex rhegmatogenous retinal detachments (RRDs). DESIGN: Nonrandomized, multicenter, retrospective study. PARTICIPANTS: One hundred seventy-six surgeons from 48 countries spanning 5 continents reported primary procedures for 7678 RRDs. METHODS: Reported data included clinical manifestations, the method of repair, and the outcome. MAIN OUTCOME MEASURES: Failure of retinal detachment repair (level 1 failure rate), remaining silicone oil at the study's conclusion (level 2 failure rate), and need for additional procedures to repair the detachments (level 3 failure rate). RESULTS: The main categories of complex retinal detachments evaluated in this investigation were: (1) grade B proliferative vitreoretinopathy (PVR; n = 917), (2) grade C-1 PVR (n = 637), (3) choroidal detachment or significant hypotony (n = 578), (4) large or giant retinal tears (n = 1167), and (5) macular holes (n = 153). In grade B PVR, the level 1 failure rate was higher when treated with a scleral buckle alone versus vitrectomy (P = 0.0017). In grade C-1 PVR, there was no statistically significant difference in the level 1 failure rate between those treated with vitrectomy, with or without scleral buckle, and those treated with scleral buckle alone (P = 0.7). Vitrectomy with a supplemental buckle had an increased failure rate compared with those who did not receive a buckle (P = 0.007). There was no statistically significant difference in level 1 failure rate between tamponade with gas versus silicone oil in patients with grade B or C-1 PVR. Cases with choroidal detachment or hypotony treated with vitrectomy had a significantly lower failure rate versus treatment with scleral buckle alone (P = 0.0015). Large or giant retinal tears treated with vitrectomy also had a significantly lower failure rate versus treatment with scleral buckle (P = 7×10(-8)). CONCLUSIONS: In patients with retinal detachment, when choroidal detachment, hypotony, a large tear, or a giant tear is present, vitrectomy is the procedure of choice. In retinal detachments with PVR, tamponade with either gas or silicone oil can be considered. If a vitrectomy is to be performed, these data suggest that a supplemental buckle may not be helpful. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article