Quantitative DNCB epicutaneous sensitization in leprosy patients and controls

Area of Science:

• Immunology
• Infectious Diseases
• Dermatology

Background:

• Leprosy, a chronic infectious disease, affects cell mediated immunity (CMI).
• Understanding CMI status is crucial for leprosy management and prognosis.
• The Ridley & Jopling scale classifies leprosy based on clinical and histopathological features, reflecting immune status.

Purpose of the Study:

• To assess non-specific CMI in leprosy patients across the Ridley & Jopling spectrum.
• To evaluate the impact of dapsone therapy on CMI.
• To determine the utility of DNCB sensitization and PPD testing for CMI assessment in leprosy.

Main Methods:

• Epicutaneous sensitization with 2,4-dinitrochlorobenzene (DNCB) was used to assess CMI.
• Quantitative grading of DNCB sensitization and Mantoux (Mx.) testing with 1 TU PPD were performed.
• CMI responses were analyzed in 49 leprosy patients and 16 healthy controls, with observations before and after dapsone administration.

Main Results:

• No gross depression of CMI was observed via DNCB sensitization.
• Quantitative analysis revealed a subtle CMI depression that increased progressively from milder (II) to severe (LL) leprosy.
• Mantoux testing with PPD was not a reliable indicator of CMI status in this leprosy cohort.
• Dapsone administration did not significantly alter CMI responses.

Conclusions:

• Non-specific CMI is subtly depressed in leprosy, with severity correlating to the Ridley & Jopling classification.
• Dapsone therapy does not appear to modulate CMI in leprosy patients.
• Quantitative DNCB sensitization is a more sensitive method than PPD testing for assessing CMI in leprosy.