Increase in peripheral benzodiazepine receptors on monocytes in fibromyalgia.

Abstract

The aim of this study is to evaluate the expression of Peripheral Benzodiazepine Receptors (PBRs) on leukocytes in patients affected by primary fibromyalgia and to argue their possible role in pain perception and in modulation of immunologic process. The expression of PBRs has been evaluated by flow cytometry on monocytes, on lymphocytes and on granulocytes in twenty patients with primary fibromyalgia, with indirect immunofluorescence methods. Upregulation of leukocyte PBRs expression has been demonstrated in fibromyalgia. A statistically significant difference has been documented only in monocytes. The monocyte PBRs expression was 26.74 +/- 14.84 MIF in fibromyalgia versus 17.45 +/- 8.54 MIF in controls (P < 0.023). Upregulation of PBRs expression, although not statistically significant, was also observed in lymphocytes and granulocytes. The monocyte PBRs overincrease in fibromyalgia may be due to abnormalities in the regulation of pain or to inflammation. It might perhaps explicate the possible mechanisms of therapeutic response to benzodiazepine in fibromyalgia.