Soluble complement receptor type 1 in serum and cerebrospinal fluid of patients with Guillain-Barré syndrome and multiple sclerosis

Activation of complement is critically involved in inflammatory reactions in both Guillain-Barré syndrome (GBS) and multiple sclerosis (MS). Soluble human complement receptor 1 (sCR1) blocks complement activation by both classical and alternative pathways. We studied serum and cerebrospinal fluid (CSF) concentrations of sCR1 in 23 patients with GBS, 27 patients with MS and 30 controls. No significant differences were found between patients and controls. Transient liver affection probably caused high serum sCR1 levels in two patients with GBS. The serum and CSF sCR1 levels were not correlated to the disease activity of GBS and MS, nor to the relapsing-remitting or chronic-progressive forms of MS. In GBS the CSF sCR1 levels correlated with the CSF total protein concentrations ( r = 0.9, P < 0.01), suggesting that sCR leaks from serum into CSF via a damaged blood-nerve barrier. The serum sCRl levels in GBS were slightly higher than in MS ( P < 0.05). Whether this reflects changes in the release or consumption of sCR in these patients is at present unknown.