doi:10.1006/cyto.2002.1973, available online at http://www.idealibrary.com on INCREASED EXPRESSION OF B-LYMPHOCYTE CHEMOATTRACTANT, BUT NOT PRO-INFLAMMATORY CYTOKINES, IN MUSCLE TISSUE IN RHESUS CHRONIC LYME BORRELIOSIS Andrew R. Pachner, Donna Dail, Kavitha Narayan, Kaberi Dutta, Diego Cadavid Inflammation in skeletal muscle is a consistent feature of Lyme borreliosis, both in the human disease and experimental models. This study had two goals: to evaluate the expression of selected pro-inflammatory and chemokine genes in skeletal muscle in the Rhesus model of Lyme disease, and to identify unexpected cytokine genes involved in Lyme myositis. Two different techniques for measuring cytokine messenger RNA (mRNA) levels were used to achieve these goals: gene expression microarrays and. real-time RT-PCR (Taqman). Muscle from necropsies and biopsies were used, and were obtained from both infected and uninfected non-human primates (NHPs). Although many cytokines were found expressed in muscle tissue, pro- inflammatory cytokines commonly associated with inflammation were not consistently up- regulated in infected muscles relative to uninfected muscles. However, B-lymphocyte chemoattractant (BLC), a chemokine implicated in the trafficking of B-cells into tissue, was increased in expression. This study is the first to extensively characterize cytokine gene expression in chronically inflamed tissue in Lyme borreliosis.  2002 Elsevier Science Ltd. All rights reserved. Borrelia burgdorferi, a tick borne spirochete causes a spectrum of clinical syndromes in human and other mammals, collectively known as Lyme disease. 1–3 The disease in humans and non-human primates 4–7 is char- acterized by persistent infection, variable expression of B. burgdorferi genes, 8,9 chronic, potent anti-B. burgdorferi immune response that is unable to com- pletely clear the spirochete, 10,11 and intense inflamma- tion out of proportion to the relatively low pathogen load. 8,12 Myositis frequently occurs. 13–18,61 The inflammatory infiltrate in chronic infection in cardiac and skeletal muscle in the NHP primate model is characterized by T cells, plasma cells, macrophages and B cells. 8 This infiltrate may be induced by the presence of highly inflammatory lipoproteins found in the spirochete’s outer surface; these lipoproteins have been the subject of intense study. 19–21 Tissue damage may accompany the inflammation. 8,22–26 Cytokines are an integral component of the inflammatory and immune responses. Most studies of cytokines in Lyme borreliosis have been performed with mononuclear cells, primary cultures, or cell lines; 27,28 there have been few studies of cytokine responses in inflamed tissues. Since inflammation in skeletal muscles is a hallmark of Lyme borrelio- sis, 13,14,29,30 and occurs in the Rhesus macaque, 10,11 we characterized the cytokine response involved in this inflammation in the Rhesus macaque model using two measures of cytokine gene expression: commercially available gene expression microarrays and RT-PCR utilizing the Taqman system. Our goals were to measure expression of ‘‘pro-inflammatory genes’’ in situ i.e. IL-1beta, IL-6, and TNFalpha, to measure genes upregulated in tissues in other chronic inflamma- tory diseases, as well as to identify unexpected cytokine From the Department of Neurosciences, University of Medicine and Dentistry of New Jersey—New Jersey Medical School, Newark, NJ, USA Correspondence to: Andrew R. Pachner, M.D., Department of Neurosciences, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, 185 S. Orange St., Newark, NJ 07103, USA. Tel: +1-973-972-5208; Fax: +1-973-972-5059 Received 18 May 2002; received in revised form 22 July 2002; accepted for publication 25 July 2002 1043–4666/02/$-see front matter.  2002 Elsevier Science Ltd. All rights reserved. Abbreviations: B. burgdorferi—Borrelia burgdorferi; GAPDH— glyceraldehyde 3-phosphate dehydrogenase; GDNF—glial- derived neurotrophic factor; HK—housekeeping; IL— interleukin; mRNA—messenger ribonucleic acid; NHP—non- human primate; RT-PCR—reverse transcriptase-polymerase chain reaction; TNF—tumor necrosis factor CYTOKINE, Vol. 19, No. 6 (21 September), 2002: pp 297–307 297