Identification of circulating biomarkers in sera of Plasmodium knowlesi-infected malaria patients - comparison against Plasmodium vivax infection
BMC INFECTIOUS DISEASES
Authors: Chen, Yeng; Chan, Choon K.; Kerishnan, Jesinda P.; Lau, Yee L.; Wong, Yin-Ling; Gopinath, Subash C. B.
Abstract
Background: Plasmodium knowlesi was identified as the fifth major malaria parasite in humans. It presents severe clinical symptoms and leads to mortality as a result of hyperparasitemia in a short period of time. This study aimed to improve the current understanding of P. knowlesi and identify potential biomarkers for knowlesi malaria. Methods: In the present study, we have employed two-dimensional gel electrophoresis-coupled immunoblotting techniques and mass spectrometry to identify novel circulating markers in sera from P. knowlesi-infected patients. Specifically, we have compared serum protein profiles from P. knowlesi-infected patients against those of healthy or P. vivax-infected individuals. Results: We identified several immunoreactive proteins in malarial-infected subjects, including alpha-2-HS glycoprotein (AHSG), serotransferrin (TF), complement C3c (C3), hemopexin (HPX), zinc-2-alpha glycoprotein (ZAG1), apolipoprotein A1 (Apo-A1), haptoglobin (HAP), and alpha-1-B-glycoprotein (A1BG). However, only TF and HPX displayed enhanced antigenicity and specificity, suggesting that they might represent valid markers for detecting P. knowlesi infection. Additionally, six P. knowlesi-specific antigens were identified (K15, K16, K28, K29, K30, and K38). Moreover, although HAP antigenicity was observed during P. vivax infection, it was undetectable in P. knowlesi-infected subjects. Conclusions: We have demonstrated the application of immunoproteomics approach to identify potential candidate biomarkers for knowlesi malaria infection.
Association of AHSG Gene Polymorphisms With Fetuin-A Plasma Levels and Cardiovascular Diseases in the EPIC-Potsdam Study
CIRCULATION-CARDIOVASCULAR GENETICS
Authors: Fisher, Eva; Stefan, Norbert; Saar, Kathrin; Drogan, Dagmar; Schulze, Matthias B.; Fritsche, Andreas; Joost, Hans-Georg; Haering, Hans-Ulrich; Hubner, Norbert; Boeing, Heiner; Weikert, Cornelia
Abstract
Background-Elevated circulating levels of fetuin-A in blood have been associated with increased risk of cardiovascular disease. The goal of our study was to prospectively investigate the potential causal nature of the association between fetuin-A levels and myocardial infarction (MI) and ischemic stroke by applying a Mendelian randomization approach. Methods and Results-Five tagging single-nucleotide polymorphisms (rs2248690, rs2070633, rs2070635, rs4917, and rs6787344) capturing the common genetic variation of the fetuin-A coding gene alpha(2)-Heremans-Schmid glycoprotein (AHSG) were genotyped in a case-cohort comprising 214 MI cases, 154 ischemic stroke cases, and 2152 persons who remained free of cardiovascular disease events in the European Prospective Investigation into Cancer and Nutrition-Potsdam study. One single-nucleotide polymorphism (rs6787344) was discarded because of Hardy-Weinberg disequilibrium. All AHSG tagging single-nucleotide polymorphisms were associated with fetuin-A plasma levels (P < 0.0001). AHSG rs4917 C>T showed the strongest association, explaining 21.2% of the phenotypic variance independent of potential confounding factors (+35.5 mu g/mL increase per C-allele, P=2x10(-121)). Furthermore, the rs4917 C-allele showed a significant association with MI (adjusted hazard rate ratio [RR] 1.34, 95% CI 1.05 to 1.70, P=0.02). Based on this association, the expected RR for MI corresponding to 1 SD in fetuin-A was 1.54 and, thus, strikingly matches the previously observed association between fetuin-A plasma levels and MI risk (RR 1.59). Conclusions-These data provide evidence for the causal nature of the recently reported association between fetuin-A plasma levels and MI risk, thereby suggesting an involvement of fetuin-A in the pathogenesis of cardiovascular disease. (Circ Cardiovasc Genet. 2009;2:607-613.)