Geneexpression profiles of fatigued fibromyalgia patientswith different categories of pain andcatastrophizing: Apreliminary report

Background: Fibromyalgia (FM) is a chronic condition characterized by diffused musculoskeletal pain and overwhelming fatigue. Purpose: To compare the gene expression profiles of fatigued FM women with different levels of pain and catastrophizing. Methods: Nine women with FM enrolled in an active Medstar Research Institute protocol were included in the gene expression analyses of peripheral blood RNA via Affymetrix GeneChip Human Genome U133 Plus 2.0 array (Santa Clara, CA). Scores from Brief Pain Inventory, Pain Catastrophizing Scale, and Multidimensional Fatigue Inventory categorized the nine participants into pain (high, n = 3; low, n = 6) and catastrophizing groups (high, n = 5; low, n = 4). Discussion: Differential expression of 107 genes between the high and low pain groups and 139 genes between the high and low catastrophizing groups (over 2.0-fold change, p < .05) were observed. Network analyses showed interferon signaling and interferon regulatory activation factor pathways distinguished between the pain groups whereas dendritic cell maturation delineated between the catastrophizing groups. Conclusion: Findings provide preliminary evidence that specific physiological pathways may possibly delineate pain and catastrophizing mechanisms. Further investigation via the use of a larger and more homogenous sample is warranted.