Correlation of skin and nerve histopathology in leprosy.

Discrepancies have been noted in the histopathological findings between skin and nerve lesions of leprosy patients in some recent works. We studied concurrent skin and nerve biopsies in 27 randomly selected leprosy patients to correlate the histopathological features of skin and nerve lesions, and to assess the importance of neural histology in the classification of leprosy. Skin and nerve biopsies were diagnostic of leprosy in 23 and 26 patients, respectively. A discrepancy was found between the two in 15 cases. Neural histology was helpful in the classification of determinate forms in 24 cases while dermal histology was significant only in 16 patients. A multibacillary nerve and paucibacillary skin picture was observed in 3 patients. It was concluded that nerve biopsy is more informative and specific than skin biopsy in the diagnosis of leprosy and further helps to classify the patients when the skin histology is indeterminate or nonspecific.

Mycobacterium leprae soluble antigen (Rees) skin test responses in an endemic population in India.

The response to intradermal administration of Rees soluble skin test antigen was studied in 12,142 randomly selected individuals living in a highly endemic area in South India. Taking a cut-off point of 12 mm induration as the criterion for 'positivity', 73% of PB cases, 45% of MB cases and 63% of noncase population (67% in contacts and 63% in non-contacts) were found to be positive. Age-specific positivity rates were higher in males than in females and in adults than in children. The difference in age-adjusted positivity rates between cases, contacts an noncontacts in the female population was found to be significant. However, the differences in reaction response are not sufficient to identify the sub-populations of cases, contacts and noncontacts and as such this antigen is not likely to be useful in epidemiological studies of infection and evolution of clinical disease in high endemic populations.

Is bacteriological examination by skin smear necessary in all paucibacillary leprosy patients in mass control programmes?

Skin smear bacteriological examination results of 11,255 paucibacillary leprosy patients from 8 leprosy control units under the National Leprosy Eradication Programme (NLEP) in South India and the Outpatient Department (OPD) of the Central Leprosy Teaching & Research Institute (CLT&RI), Chengalpattu, between 1987 and 1989 were collected and analysed. Only 0.05% of the smears from leprosy control units and 2.49% from the OPD of CLT&RI were found to be positive. Not a single smear from indeterminate, tuberculoid and pure neuritic types of leprosy out of 8263 examined was found positive under field conditions. The relevance of carrying out routine bacteriological examination in mass leprosy control programmes is discussed.