[Neurofibromatosis (NF1) and neuroleprosy: immunoreaction against pathologic Schwann-cells. Physiopathogenetic observations].

BACKGROUND: We reviewed the literature evaluating the immune reaction in neurofibromatosis (NF1) and neuroleprosy, so as to underline the immunopathegenetic parallelism and the possible therapeutic implications regarding the treatment of these two disorders. In particular we evaluated the systemic modifications and the local fibrotic events that lead to nerve damage in NF1 and complete neuronal destruction as in leprosy.

METHODS: With the above aim in mind we studied the histology, histochemistry and immunohistochemistry (Schwann cells and immunoglobulins) of four plexiform neurofibroma, one common neurofibroma and one case of borderline neuroleprosy (BT).

RESULTS: Two plexiform neurofibromas showed an evident immune reaction that was antibody mediated with numerous IgG; the remaining neurofibromas represented other stages of disease evolution and disease quiescence and thus showed a scarce immune reaction with a reduced presence of immunoglobulins. All the neurofibromas showed the presence of fibrous bundles. In the case of neuroleprosy (BT), the immune reaction was modest, immunoglobulins were present and fibrotic transformation on neuronal fibers was observed.

CONCLUSIONS: Being that pathologic Schwann cell are the site of immune reactions that can become abnormal (at times with autoimmune reactions), clinical as well as biochemical surveillance of leprous neuropathy and NF1 could allow for a timely modification of the abnormal reaction with selective immunomodulators. The inactivation of the mycobacterial RNA polymerase or of the NF1 gene could offer hope for controlling disease activity and disease evolution of the two disorders.