Autoimmunity and inflammation in the peripheral nervous system

Peripheral Nerve Society Biennial Meeting, organized in conjunction with the Austrian Federal Ministry of Education, Research and Culture, held at Telfs, Tyrol, Austria from 8-12 September 2001

Macrophage clustering as a diagnostic marker in sural nerve biopsies of patients with CIDP.

Contains fulltext : 48742.pdf (publisher's version ) (Closed access)BACKGROUND: In adult patients with a slowly progressive demyelinating neuropathy, it may be difficult to distinguish between a hereditary neuropathy and chronic inflammatory demyelinating polyneuropathy (CIDP). The authors previously observed clustering of macrophages around endoneurial blood vessels in sural nerve biopsies from patients with CIDP. OBJECTIVES: To quantitate macrophage clustering around endoneurial blood vessels in CIDP vs hereditary neuropathies. METHODS: The authors studied 21 patients with CIDP, 18 patients with hereditary neuropathies, and 5 normal sural nerves. Numbers of macrophages, T-cells, and blood vessels were counted after immunohistochemical staining. The presence of three or more macrophages around one blood vessel was defined as a cluster. In a subsequent validation analysis, 65 stored biopsy specimens obtained from patients with a chronic neuropathy were re-evaluated for perivascular macrophage clustering according to criteria derived from the quantitative analysis of the first 221 biopsies in a blinded fashion. RESULTS: The percentage of endoneurial vessels with macrophage clusters was higher in CIDP than in hereditary neuropathies (CIDP median = 9.4, range 0 to 48; hereditary NP median = 0, range 0 to 7.7; p < 0.001). The evaluation of the 65 further biopsies showed that the presence of one perivascular macrophage cluster per fascicle proved to be a valid criterion to differentiate between inflammatory and other forms of neuropathy (chi2 test p = 0.0000025, sensitivity 75%, specificity 72%). CONCLUSION: The presence of clusters of macrophages around endoneurial vessels in sural nerve biopsies may serve as a useful additional marker for establishing the pathologic diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP)

Autoimmune responses in peripheral nerve

The PNS is an immunocompetent organ. The participating cellular and humoral elements in the local immune circuitry have been identified. A number of acute and chronic neuropathies appear to result from disturbed immune homeostasis. The model disorder EAN has been useful in examining the induction, amplification and effector phase of autoimmune responses to peripheral nerve antigens. Potential autoantigens contained in the myelin sheath and on the axolemma have been characterized. Thus, the recent years have seen a rapid growth of information concerning the pathogenesis of the important group of immune-mediated neuropathies. It can be anticipated that the better understanding of the principal mechanisms of autoimmunity in the PNS will aid in the development of more specific and efficacious treatments for these crippling diseases