Immunological Investigations, 40:735–750, 2011 Copyright © Informa Healthcare USA, Inc. ISSN: 0882-0139 print / 1532-4311 online DOI: 10.3109/08820139.2011.599088 Variation in Genes of β-glucan Recognition Pathway and Susceptibility to Opportunistic Infections in HIV-Positive Patients Diana C. Rosentul, 1,2 Theo S. Plantinga, 1,2 Antonios Papadopoulos, 3 Leo A. B. Joosten, 1,2 Anastasia Antoniadou, 3 Hanka Venselaar, 4 Bart-Jan Kullberg, 1,2 Jos W. M. van der Meer, 1,2 Evangelos J. Giamarellos-Bourboulis, 3 and Mihai G. Netea 1,2 1 Department of Internal Medicine, Nijmegen Center for Molecular Life Sciences, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands 2 Nijmegen Institute for Infection, Inflammation and Immunity (N4i) Nijmegen Center for Molecular Life Sciences, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands 3 University of Athens Medical School, Athens, Greece 4 Center for Molecular and Biomolecular Informatics, Nijmegen Center for Molecular Life Sciences, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands Opportunistic infections are the main cause of morbidity and death among HIV-positive patients. Most of these infections are linked to the immunodeficiency due to low CD4 + counts. However, not all patients with low CD4 + counts are equally susceptible to infec- tions, and we hypothesize that variability in genes of innate immunity may also play an important role. The dectin-1/CARD9 pathway is crucial for recognition of both fungal and bacterial pathogens. The aim of this study was to assess the possible association between the occurrence of opportunistic infections and single nucleotide polymorphisms in DECTIN-1 and CARD9 in a cohort of 187 HIV-infected patients. The incidence of oropharyngeal candidiasis and other opportunistic infections was not influenced by either the Y238X DECTIN-1 or the S12N CARD9 polymorphism. Surprisingly however, the prevalence of pneumonia was significantly higher in patients bearing the defective Address correspondence to Mihai G. Netea, Department of Medicine (463), Radboud University Nijmegen Medical Centre, P.O. Box 9101, Geert Grooteplein 8, 6500 HB Nijmegen, The Netherlands. E-mail: M.Netea@aig.umcn.nl