T-CELL-MEDIATED EPINEURIAL VASCULITIS AND HUMORAL-MEDIATED MICROANGIOPATHY IN CRYOGLOBULINEMIC NEUROPATHY

We used immunohistochemistry to assess the role of humoral and cellula r factors in endoneurial microangiopathy and epineurial vasculitis in 15 nerve biopsies of patients with axonal neuropathy and monoclonal or mixed cryoglobulinemia (CG). Deposition of immunoglobulins and cytoly tic complement was detected in endoneurial capillaries of patients wit h mixed CG. Epineurial inflammatory infiltrates containing beta 2-inte grin-positive lymphocytes and monocytes surrounded arterioles expressi ng cell adhesion molecules, thus suggesting a cell-mediated pathogenes is of the epineurial vasculitis. On the other hand, the absence of imm une complex deposition and polymorphonuclear elements suggests a minor role for the humoral mechanisms in the formation of the vasculitic le sions. This study indicates that both cell-mediated mechanisms and imm une complexes/cryoglobulins are involved, although at different levels , in the pathogenesis of CG neuropathy.