Gene expression analysis of histamine receptors in peripheral blood mononuclear cells from individuals with clinically-isolated syndrome and different stages of multiple sclerosis.

Along with their established role in allergic reactions, histamine and its receptors have been implicated in the pathology of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis. In this study we analyzed the gene expression of histamine receptor 1 (HRH1), HRH2 and HRH4 in peripheral blood mononuclear cells derived from patients with clinically isolated syndrome (CIS), relapsing-remitting (RR) MS, secondary-progressive (SP) MS, primary-progressive (PP) MS, and healthy controls (HC). We found that HRH1 transcript was significantly down-modulated in SP-MS compared with HC, and HRH4 was increased in this group compared to HC, CIS and RR-MS. No other differences in the expression of histamine receptors were observed between HC, CIS and other clinical forms of definite MS.