Taken together, our data indicate that TG2 transiently appears in developing OPCs and promotes early OPC differentiation, while its absence in OPCs in MS lesions, irrespective of the presence of inflammatory activity, may contribute to remyelination failure (Franklin and ffrench-Constant, 2008; Kuhlmann et al., 2008). The gene discussed is TGM2; the disease is myeloid sarcoma.