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2015. DOI: 10.1038/srep07865

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Congress of Nanotechnology; 2007. pp. 1-2

Leyla Bilik, Betul Demir and Demet Cicek

Additional information is available at the end of the chapter Leyla Bilik, Betul Demir and Demet Cicek Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.72481

#### Abstract

Sudden changes in immune-mediated response to Mycobacterium leprae antigen are referred to as leprosy reactions. The reactions manifest as acute inflammatory episodes rather than chronic infectious course. There are mainly two types of leprosy reactions. Type 1 reaction is associated with cellular immunity and particularly with the reaction of T helper 1 (Th1) cells to mycobacterial antigens. This reaction involves exacerbation of old lesions leading to the erythematous appearance. Type 2 reaction or erythema nodosum leprosum (ENL) is associated with humoral immunity. It is characterized by systemic symptoms along with new erythematous subcutaneous nodules.

DOI: 10.5772/intechopen.72481

Keywords: leprosy, type 1 reaction, reversal reaction, type 2 reaction, erythema nodosum leprosum

#### 1. Introduction

Sudden changes in immune-mediated response to Mycobacterium leprae antigen are referred to as leprosy reactions. The reactions manifest as acute inflammatory episodes rather than chronic infectious course [1]. These reactions account for about 30–50% of cases with leprosy [2]. Both patients with low and high load of leprosy bacilli are at risk of developing leprosy reactions. Leprosy reactions can occur at any time before, during, or after the treatment. Patients with fewer skin lesions and without nerve involvement are less likely to develop leprosy reactions. The presence of multiple lesions in close proximity to peripheral nerves, facial involvement, and presence of nerve thickening without functional impairment are risk factors for the development of leprosy reactions. Patients developing leprosy reactions are more likely to develop sequelae or deformities [3]. There are mainly two types of leprosy reactions. Type 1 reaction involves exacerbation of old lesions leading to the erythematous appearance. Type 2 reaction is an immune complex-mediated reaction. It is characterized by systemic symptoms along with new erythematous subcutaneous nodules [4].

© 2017 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited.
