Fibrosis: a distinguishing feature in the pathology of neural leprosy.

Sérgio Luiz Gomes Antunes,José Augusto Da Costa Nery,Eduardo Alves Freire Da Costa,Márcia Rodrigues Jardim,Anna Maria Sales,Bernardo Miguel De Oliveira Pascarelli,Thaís Porto Amadeu,Robson Teixeira Vital,Euzenir Nunes Sarno

doi:10.1590/0074-02760190056

Sérgio Luiz Gomes Antunes, José Augusto Da Costa Nery + Show 7 more

Open Access

https://doi.org/10.1590/0074-02760190056

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Abstract

BACKGROUND Fibrosis in the peripheral nerve is the end stage of leprous neuropathy and the cause of the resulting permanent neural function impairments. Preventive measures to avoid this irreversible pathological state are a relief strategy for leprosy sufferers.OBJECTIVES The present study describes the frequency of fibrosis along with its characterisation and pathogenic development.METHODS Six-hundred-and-thirteen nerve samples were sorted from 278 neural leprosy (NL) and 335 non-leprosy neuropathy patients (ON). The total number of samples was histologically examined by routine staining methods (haematoxylin-eosin, Wade staining and Gomori’s trichrome) and fibrosis was evaluated via semi-quantitative estimation.FINDINGS Fibrosis was most frequent in the NL group (33% against 0.4% in ON) while fibrosis in association with endoneurial microfasciculation was found in 38 (41.3%) of the NL samples in the examination of semithin sections. Pericytic activation in the perivascular environment was confirmed to be the source of the fibroblasts and perineurial cells delimiting microfascicles. End-stage fibrosis in leprosy displays an arrangement of microfascicles devoid of neural components (i.e., Schwann cells and axons) lined by an intermediate phenotype of fibroblastic-perineurial cells filled with bundles of collagen fibres.MAIN CONCLUSIONS The present study underscores that fibrosis is frequently the severe end stage of neural leprosy NL pathogeny after analysing the notably distinct development of fibrosis within the neural environment.

Highlights

Fibrosis in the peripheral nerve is the end stage of leprous neuropathy and the cause of the resulting permanent neural function impairments
The present study confirmed the evidence that nerve fibrosis is a relevant feature in leprosy neuropathy
It is known that nerve fibrosis is found in traumatic and post-radiation neuropathy.[9,10] These aetiologies were not confirmed in the other neuropathies (ON) group

Summary

METHODS

Six-hundred-and-thirteen nerve samples were sorted from 278 neural leprosy (NL) and 335 non-leprosy neuropathy patients (ON). The finding of fibrosis in the histological examination of biopsy nerve specimens, together with the clinical, electroneuromyographic and laboratory alterations (polymerase chain reaction – PCR) gleaned from suspected leprosy patients, is plausible indications of a probable leprosy diagnosis in AFB nerve samples. These criteria are strengthened in highly prevalent countries for leprosy. According to Antunes et al[7] first report, in the histopathological examination of NL, the frequency of miscrofasciculation was low (10.9%) It was only found in the leprosy nerve samples and not in the ones of non-leprosy neuropathies. The peculiar fibrogenic process underway in NL has been closely analysed to demonstrate the interactions among the endoneurial fibroblasts, perineurial cells, pericytes, Schwann cells and microfascicles that contribute to the final, irreversible fibrotic configuration of the nerves in leprosy disease

MATERIALS AND METHODS

Materials and Methods

DISCUSSION