Brief report Monocyte chemoattractant protein-1 (MCP1) promoter -2518 polymorphism may confer a susceptibility to major depressive disorder in the Korean population Chi-Un Pae a , Hye-Sook Yu a , Tae-Suk Kim a , Chang-Uk Lee a , Soo-Jung Lee a , Tae-Youn Jun b , Chul Lee a , Alessandro Serretti c , In-Ho Paik a, * a Department of Psychiatry, Kangnam St. Mary’s Hospital, Catholic University of Korea College of Medicine, 505 Banpo-Dong, Seocho-Gu, Seoul 137-701, Republic of Korea b Department of Psychiatry, St. Mary’s Hospital, Catholic University of Korea College of Medicine, Seoul, Republic of Korea c Department of Psychiatry, Vita-Salute University, San Raffaele Institute, Milan, Italy Received 18 September 2003; accepted 21 April 2004 Abstract We conducted a case – control association study of the monocyte chemoattractant protein-1 (MCP1) gene -2518 polymorphism in 90 patients with major depressive disorder. Genotyping was performed by polymerase chain reaction methods. We found significant differences in genotype and allele frequencies. The present study suggests that this polymorphism may confer a susceptibility to major depressive disorder in the Korean population. D 2004 Elsevier Ireland Ltd. All rights reserved. Keywords: Major depressive disorder; MCP1 gene -2518 polymorphism 1. Introduction The most consistent finding regarding alterations of cytokine levels in patients with major depressive dis- order (MDD) is a reported increase of interleukin (IL)- 6 production (for review, see Maes et al., 1997; Kubera et al., 2000; Zorrilla et al., 2001). Other abnormalities that have been reported include increased production of IL-12 (Kim et al., 2002b), interferon-g (Kubera et al., 2001), and IL-10 (Kubera et al., 2000), and decreased production of IL-2 (Maes et al., 1995). Given the role of IL-2 and IL-12 in the T-helper 1 (TH-1) system and of IL-6 and IL-10 in the T-helper 2 (TH-2) system, it has been suggested that TH-1 and TH-2 immune system alterations may be linked to the development of MDD (for review, see Schwarz et al., 2001). Monocyte chemoattractant protein-1 (MCP1) plays an essential role in modulating TH-1/TH-2 responses (Traynor et al., 2002). Because MCP1 could affect the innate immunity and adaptive immunity through the regulation of monocytes and TH response, respective- ly (Gu et al., 2000), studies of MCP1 are germane to the TH-1/TH-2 hypothesis of the development of MDD (Schwarz et al., 2001). Recently, a transition from guanine (G) to adenine (A) at position -2518 in 0165-1781/$ - see front matter D 2004 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.psychres.2004.04.004 * Corresponding author. Tel.: +82-2-590-2780; fax: +82-2-536- 8744. E-mail address: knpsy@catholic.ac.kr (I.-H. Paik). www.elsevier.com/locate/psychres Psychiatry Research 127 (2004) 279 – 281