Cutaneous delayed-type hypersensitivity responsiveness in lepromatous and borderline lepromatous leprosy patients as determined by MULTITEST® CMI

To assess cell mediated immune (CMI) function in patients with lepromatous and borderline lepromatous leprosy (LL and BL), 35 patients were examined with the MULTITEST® CMI system to evaluate cutaneous delayed-type hypersensitivity (DTH) responsiveness to 7 recall antigens. Reactions were assessed quantitatively and qualitatively. In addition, patients were classified as responsive(≥ 2 positive reactions), hypo-responsive (1 positive reaction), or anergic. Only hyporesponsive and anergic patients were re-tested. In 23 patients tested before treatment started (Group 1), 9 were responsive, 4 hypo-responsive, and 10 anergic. Upon re-testing, 10 of the 14 hyporesponsive-anergic subjects showed improvement. In 12 patients assessed after therapy initiation (Group 2), 9 were responsive and 3 others became responsive upon re-testing. Quantitative assessment indicated variable deficiencies in cutaneous DTH reactivity that, in many cases, improved with therapy. Correlations between reactivity and disease severity (LL versus BL) or duration of disease were not observed. The MULTITEST® CMI system provided a convenient, safe, and reproducible method to assess cutaneous DTH responsiveness in LL and BL patients. Our findings indicated that most LL and BL patients are able to generate detectable but generally fewer and less robust cutaneous DTH responses to recall antigens, many improving with therapy. However, a semi-quantitative classification whereby patients that reacted to 2 or more antigens were considered responsive showed little difference between patients and controls. Overall, the data support the contention that deficits in cutaneous DTH responsiveness probably neither predispose nor necessarily accompany lepromatous disease, a practical consideration as efforts to develop a leprosy vaccine continue.