Putative salivary biomarkers useful to differentiate patients with fibromyalgia

Fibromyalgia (FM) is a chronic pain disorder characterized by widespread pain and associated with unspecific symptoms. So far, no laboratory tests have been validated. The aim of the present study was to investigate the presence in saliva of potential diagnostic and/or prognostic biomarkers which could be useful for the management of FM patients. Specifically, the salivary profile of FM patients was compared with those of healthy subjects, subjects suffering migraine (model of non-inflammatory chronic pain), and patients affected by rheumatoid arthritis (model of inflammatory chronic pain). For proteomics analysis 2-DE and SELDI-TOF-MS were applied. From 2-DE serotransferrin and alpha-enolase were found differentially expressed in FM. Hence, their expression was validated by ELISA together with phosphoglycerate-mutase-I and transaldolase, which were found in a previous work. Moreover, ROC curve was calculated by comparing FM patients versus control subjects (healthy plus migraine) to investigate the discriminative power of biomarkers. The best performance was obtained by combining alpha-enolase, phosphoglycerate-mutase-I and serotransferrin. On the other hand, none of the candidate proteins showed a statistical correlation with clinical features. Finally, preliminary SELDI analysis highlighted two peaks whose identification need to be validated. Overall, these results could be useful in supporting the clinical diagnosis of FM. Significance: FM is one of the most common chronic pain condition which is associated with significant disability. The fibromyalgic pain is a peculiar characteristic of this disease and FM patients suffer from reduced quality of life, daily functioning and productivity. Considering the deep complexity of FM, the discovery of more objective markers is crucial for supporting clinical diagnosis. Therefore, the aim of the present study was the selection of biomarkers effectively associated with fibromyalgic pain which will enable clinicians to ach