Histopathological Patrern of Early Syphilis.

Thirty six untreated cases of early syphilis comprising 10 primary and 26 secondary syphilis were included in the study. Primary syphilis depicted classical istopathological features of ulceration, exocytosis, perivascular infiltrate of lympocytes and plasma cells along with endothelial cell proliferation. Secondary syphilis, however, depicted intriguing features. Lichenoid infiltrate along with basal layer dissolution was seen in 3 and psoriasiform appearance in 1 cases. Three cases showed granulomatous reaction. One case manifesting as pruritic follicular rash had classical features on histopathology. Vascular changes were absent or inconspicuous in as many as 22.2% and 8.3% respectively.

Histochemical Profile of Vitiligo.

Fifty untreated vitiligo patients were subjected to histo-chemical examination using dopa reaction technique. Dopa positive melanocytes were absent in a large majority (82%) of cases. Increase in the number of supra-basal clear cells was observed in 70 percent. Presence of inflammatory infiltrate at dermo- epidermal junction along with basal cell layer-dissolution was seen in 7 cases. Grayish-black, void cells considered to be inactive melanocytes, were seen in the basal layer.

Histoid leprosy--a histopathological reapparel.

Twenty three clinically diagnosed histoid leprosy patients were subjected to histopathological and histochemical investigations. The histopathological features were comprise of a well-formed lesion surrounded by a pseudocapsule. In addition, a free, midly eosinophilic, uninvolved sub-epidermal zone, and variously arranged spindle-shaped histiocytes were noted in the lesion. Polygonal and foamy histiocytes were also sited in a few sections. The lesion also had a large number of solid staining acid-fast lepra bacilli. The latter might have stimulated a peculiar histiocytic tissue response almost identical to that seen in histiocytoma(cutis) but for the absence of haemosidrin and lipids.

The histopathology of type I (lepra) and type II (ENL) reactions in leprosy.

The histopathological features in type I (lepra) reaction comprised a loose and disorganised granuloma in the upper and mid-dermis, dermal edema and variable cellular contents, namely, epithelioid cells, lymphocytes, giant cells, and macrophages. While ENL reactions, were characterised by predominant involvement of subcutaneous vessels, vasculitis, and polymorphonuclear infiltration in and around the blood vessels.

Erythema nodosum leprosum (ENL) in histoid leprosy.

The morphological features of ENL, occurring in histoid leprosy are described. Its infrequent occurrence has been emphasised. The possible immunopathogenesis of its occurrence in histoid leprosy is briefly outlined.

Impairment of Jones-Mote hypersensitivity and specific antibody response against depolymerized flagellin in lepromatous leprosy.

Cutaneous hypersensitivity and antibody-producing capacity were assessed in patients with lepromatous leprosy with defective immunity, by immunizing them with monomeric flagellin from Salmonella adelaide. Results were compared with those of controls, matched for age and sex, derived from similar socioeconomic stratum, but without any defect of the immunological system. In contrast to the normal individuals, who showed Jones-Mote type of hypersensitivity, no lepromatous patient could mount any 'delayed-in-time' cutaneous hypersensivivity reaction against an intradermal challenge of monomeric flagellin. However, when immunized through the subcutaneous route, both groups could produce adequate amounts of specific serum antibody. In addition to this unique split tolerance found in all lepromatous patients, some patients showed low levels of 'natural' IgM antibody, reduced formation of specific antibody when immunized through the subcutaneous route, and incomplete maturation of IgG class of anti-flagellin antibody. When immunized by the intradermal route, however, production of both anti-flagellin antibody and maturation of IgG antibody was significantly inhibited in normal adults but not in lepromatous patients. Thus, contrary to the earlier concept of hyperactivity of the humoral immune apparatus in lepromatous leprosy, the present study detected B-cell hypofunction in some patients.