TY  - JOUR
A1  - Mueller, A.
A1  - Stoetter, L.
A1  - Kalluvya, S.
A1  - Stich, A.
A1  - Majinge, C.
A1  - Weissbrich, B.
A1  - Kasang, C.
T1  - Prevalence of hepatitis B virus infection among health care workers in a tertiary hospital in Tanzania
JF  - BMC Infectious Diseases
N2  - Background: Sub-Saharan Africa has a high prevalence of hepatitis B virus (HBV) infections. Health care workers (HCWs) are at high risk of contracting HBV infection through their occupation. Vaccination of HCWs against HBV is standard practice in many countries, but is often not implemented in resource-poor settings. We aimed with this cross-sectional study to determine HBV prevalence, HCW vaccination status, and the risk factors for HCWs contracting HBV infection in Tanzania. 
Methods: We enrolled 600 HCWs from a tertiary Tanzanian hospital. Their demographics, medical histories, HBV vaccination details and risk factors for contracting blood-borne infections were collected using a standardized questionnaire. Serum samples were tested for HBV and hepatitis C virus (HCV) markers by ELISA techniques, PCR and an anti-HBs rapid test. HCWs were divided in two subgroups: those at risk of contracting HBV (rHCW 79.2 %) via exposure to potentially infectious materials, and those considered not at risk of contracting HBV (nrHCW, 20.8 %). Results: The overall prevalence of chronic HBV infection (HBsAg+, anti-HBc+, anti-HBs-) was 7.0 % (42/598). Chronic HBV infection was found in 7.4 % of rHCW versus 5.6 % of nrHCW(p-value = 0.484). HCWs susceptible to HBV (HBsAg-, anti-HBc-, anti-HBs-) comprised 31.3 %. HBV immunity achieved either by healed HBV infection (HBsAg-, anti-HBc+, anti-HBs+) or by vaccination (HBsAg-, anti-HBc-, anti-HBs+) comprised 36.5 % and 20.2 %, respectively. 4.8 % of participants had indeterminate results (HBsAg-, anti-HBc+, anti-HBc-IgM-, anti-HBs-). Only 77.1 % of HCWs who received a full vaccination course had an anti-HBs titer > 10 ml/U. An anti-HBs point-of-care test was 80.7 % sensitive and 96.9 % specific. There was a significantly higher risk for contracting HBV (anti-HBc+) among those HCW at occupational risk (rHCW) of older age (odds ratios (OR) in rHCW 3.297, p < 0.0001 vs. nrHCW 1.385, p = 0.606) and among those HCW being employed more than 11 years (OR 2.51, p < 0.0001***). HCV prevalence was low (HCV antibodies 1.2 % and HCV-RNA 0.3 %). 
Conclusions: Chronic HBV infection is common among Tanzanian HCWs. One third of HCWs were susceptible to HBV infection, highlighting the need for vaccination. Due to high prevalence of naturally acquired immunity against HBV pre-testing might be a useful tool to identify susceptible individuals.
KW  - hepatitis C virus
KW  - point-of-care test
KW  - human-immunodeficiency-virus
KW  - C virus
KW  - seroprevalence
KW  - syphilis
KW  - vaccine
KW  - Uganda
KW  - blood
KW  - hepatitis B virus
KW  - health care workers
KW  - Tanzania
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-141786
VL  - 15
IS  - 386
ER  - 
TY  - JOUR
A1  - Schatton, Tobias
A1  - Yang, Jun
A1  - Kleffel, Sonja
A1  - Uehara, Mayuko
A1  - Barthel, Steven R.
A1  - Schlapbach, Christoph
A1  - Zhan, Qian
A1  - Dudeney, Stephen
A1  - Mueller, Hansgeorg
A1  - Lee, Nayoung
A1  - de Vries, Juliane C.
A1  - Meier, Barbara
A1  - Beken, Seppe Vander
A1  - Kluth, Mark A.
A1  - Ganss, Christoph
A1  - Sharpe, Arlene H.
A1  - Waaga-Gasser, Ana Maria
A1  - Sayegh, Mohamed H.
A1  - Abdi, Reza
A1  - Scharffetter-Kochanek, Karin
A1  - Murphy, George F.
A1  - Kupper, Thomas S.
A1  - Frank, Natasha Y.
A1  - Frank, Markus H.
T1  - ABCB5 Identifies Immunoregulatory Dermal Cells
JF  - Cell Reports
N2  - Cell-based strategies represent a new frontier in the treatment of immune-mediated disorders. However, the paucity of markers for isolation of molecularly defined immunomodulatory cell populations poses a barrier to this field. Here, we show that ATP-binding cassette member B5 (ABCB5) identifies dermal immunoregulatory cells (DIRCs) capable of exerting therapeutic immunoregulatory functions through engagement of programmed cell death 1 (PD-1). Purified Abcb5\(^+\) DIRCs suppressed T cell proliferation, evaded immune rejection, homed to recipient immune tissues, and induced Tregs in vivo. In fully major-histocompatibility-complex-mismatched cardiac allotransplantation models, allogeneic DIRCs significantly prolonged allograft survival. Blockade of DIRC-expressed PD-1 reversed the inhibitory effects of DIRCs on T cell activation, inhibited DIRC-dependent Treg induction, and attenuated DIRC-induced prolongation of cardiac allograft survival, indicating that DIRC immunoregulatory function is mediated, at least in part, through PD-1. Our results identify ABCB5\(^+\) DIRCs as a distinct immunoregulatory cell population and suggest promising roles of this expandable cell subset in cellular immunotherapy.
KW  - mesenchymal stem cells
KW  - P-glycoprotein
KW  - regulatory T cells
KW  - maintain immune homeostasis
KW  - malignant melanoma
KW  - in vivo
KW  - skin
KW  - generation
KW  - transplant
KW  - tolerance
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-149989
VL  - 12
SP  - 1564
EP  - 1574
ER  -