Immuno-histopathology in the diagnosis of early leprosy.

The present study of 45 early leprosy cases in an endemic area in China indicates: a) Sensitivity of acid-fast bacilli (AFB) detection can be significantly improved by examining approximately 30 serial sections. AFB and/or phenolic glycolipid-I (PGL-I) were mostly detected in the infiltrates in the subepidermal zone, intraneurium, perineurium and around blood vessels. b) PGL-I antigen was positive in 10 clinically suspected, single lesion leprosy cases and AFB positive in 7 patients, AFB and/or PGL-I in nerve in 6 patients. c) Nonspecific chronic inflammation in indeterminate leprosy presented as selective perineural and/or intraneural infiltration with lymphocytes predominating. In the infiltrating mass, fragments of neural tissue were demonstrated with anti-S-100 protein staining. d) Except for 3 cases with unknown numbers of lesions, the present positive immunohistopathological findings are in direct correlation with the number of lesions at first diagnosis, namely: 41.6% (10/24) for single lesion, 66.6% (6/9) for 2 lesions, and 88.8% (8/9) for patients with > or = 3 lesions. e) Typical epithelioid or macrophage granuloma formations were not seen in early leprosy with a single lesion. In testing the immunological inclination of these patients with CD68 or tumor necrosis factor-alpha (TNF-alpha) a positive test is likely to be of prognostic value since TNF-alpha is involved in granuloma formation and nerve damage.