AUTOREACTIVE T-CELL AND B-CELL RESPONSES TO MYELIN ANTIGENS AFTER DIAGNOSTIC SURAL NERVE BIOPSY

To study whether nervous tissue trauma provokes myelin antigen autorea ctive T and B cell responses in humans we examined consecutive blood s amples from 7 patients with polyneuropathy undergoing diagnostic sural nerve biopsy and 8 control patients undergoing other types of minor s urgery. The antigen-specific T cells were assessed by enumerating cell s secreting interferon-gamma (IFN-gamma) in response to the myelin com ponents P0, P2, myelin basic protein (MBP) and myelin associated glyco protein (MAG), and to 4 selected MBP peptides. B cell mediated immunit y was assessed by counting numbers of cells secreting antibodies direc ted against the myelin proteins. On day 7 after biopsy, there were 3-1 0-fold increased numbers of T and B cells reactive with P0, P2, MBP an d MAG in blood of polyneuropathy patients compared to controls, while levels of cells recognizing purified protein derivate or responding to phytohemagglutinin (PHA) did not differ significantly. Comparison of prebiopsy levels on day 0 with post-biopsy levels on day 7 in the poly neuropathy patients revealed a significant increase in T cells recogni zing P0, P2 and MAG, and in B cells secreting IgG antibodies against P 0 and P2. On day 14 after nerve biopsy these differences were no longe r seen. We suggest that in patients with polyneuropathy, sural nerve b iopsy with the ensuing wallerian degeneration and myelin breakdown cau ses transiently increased levels of circulating myelin autoreactive T and B cells. It remains to be determined if this has a physiological r ole in nerve trauma responses and/or affects the clinicopathological c ourse of the peripheral neuropathy.