Clinical, electrophysiological, and immunopathological study of peripheral nerves in Hansen's disease.

Hansen's disease is a disease of peripheral nerves. Some patients develop peripheral neuropathy before the diagnosis of the disease, and others develop these complications after starting therapy. Electrophysiological (EP) studies were carried out in Hansen's disease patients. This work studied the neural deficits, electromyography (EMG) and motor nerve conduction (MNC) variables in different types of leprosy and the immunopathology of sural nerve tissue in patients with severe neural deficits. Forty leprosy patients had neurological examinations and EP study. Histopathological and immunopathological study of sural nerve biopsy specimens was performed for 10 patients with severe neural deficits. The results of the neurological study showed that there was involvement of cranial nerves, muscular system, motor reflexes and sensory system and trophic and vasomotor changes. EP study showed significant changes in EMG of abductor digiti minimi in patients as compared to controls. MNC variables of common peroneal nerve were abnormal in 80% of all patients, MNC of median nerve was abnormal in 72.5%, while MNC of ulnar nerve was abnormal in 70% and SNC of ulnar nerve was abnormal in 77.5% of the total. In conclusion, electrophysiological investigations have an important role in the detection of muscle denervation and neuropathic changes in leprosy patients. These investigations are safe, rapid and non-invasive techniques. On the other hand immunopathological study revealed that the degree of immune positivity correlated with the degree of nerve fibrosis.

Ultrastructural features of epithelioid cell granuloma induced by intradermal injection of xenogeneic nerve tissue.

Epithelioid cell granulomas were induced in rabbits previously sensitised with human sensory peripheral nerve extract by skin testing with homogenate of sural nerve. Ultrastructurally some of the cells contained in their cytoplasm abundant and dilated rough endoplasmic reticulum filled with a moderately dense product while the cytoplasm of other cells contained numerous membrane-bound vesicles. These cells show all the ultrastructural characteristics of epithelioid cells found in human granulomatous disease and in human states of granulomatous hypersensitivity. Thus we have developed an animal model which supports the concept of granulomatous hypersensitivity as a distinct entity in humans to be differentiated from foreign body and delayed-type hypersensitivity reactions. The model may also prove important in elucidating the pathogenesis of granuloma formation in non-lepromatous leprosy and other granulomatous disease and in defining the nature of the products of epithelioid cells.