Rare atypical presentations in Type 2 lepra reaction: a case series.

OBJECTIVES: Type 2 lepra reaction is a Th2-mediated type III hypersensitivity reaction in leprosy, with a characteristic cutaneous manifestation in the form of erythema nodosum leprosum (ENL). We describe unusual presentations of Type 2 lepra reaction in five patients. METHODS: Patient data and dermatological findings were analyzed in three men and two women diagnosed with Hansen's disease. RESULTS: Findings included multiple tender, polycyclic, necrotic lesions distributed over the face in one patient, and painful, fluid-filled lesions on both arms and lower limbs in another. The third patient showed erythematous, tender nodules, bullae, and necrotic ulcers over the back and upper and lower limbs. The fourth showed erythematous tender nodules over the face, neck, back, and extremities, predominantly in sun-exposed areas. The fifth revealed multiple erythematous, severely tender nodules and urticarial plaques mimicking those of Sweet's syndrome. Diagnosis of borderline or lepromatous leprosy with atypical Type 2 reaction were made in all cases. CONCLUSIONS: Type 2 lepra reactions are antigen antibody-mediated immune complex reactions that present with constitutional symptoms and ENL characterized by tender, erythematous, evanescent nodules mainly on the face, arms, and legs. Over 50% of lepromatous leprosy patients and 25% of borderline lepromatous leprosy patients experienced type 2 lepra reactions prior to the advent of multi-drug therapy. Thalidomide is the drug of choice for severe atypical lepra reactions because of its anti-tumor necrosis factor-α action. Awareness of these atypical variants and prompt diagnosis and treatment are essential to prevent mortality and morbidity in potentially treatable patients.

Administration of Ag85B showed therapeutic effects to Th2-type cytokine-mediated acute phase atopic dermatitis by inducing regulatory T cells.

Increase in the number of patients with atopic dermatitis (AD) has been recently reported. T helper (Th) cells that infiltrate AD skin lesions are Th2-type dominant; reduced exposure to environmental Th1-cytokine-inducing microbes is believed to contribute to the increased number of AD patients. Regulatory type immune responses have been also associated with the occurrence of AD. It has been reported that antigen 85B (Ag85B) purified from mycobacteria is a potent inducer of Th1-type immune response in mice as well as in humans. In this study, we have examined the effect of plasmid DNA encoding Ag85B derived from Mycobacterium kansasii on AD skin lesions induced by oxazolone (OX) application. Th2-cytokine mediated mouse AD model with immediate type response followed by a late phase reaction was developed by repeated applications of low-dose OX to sensitized mice. Mice were immunized with plasmid DNA encoding cDNA of Ag85B before OX sensitization or during repeated elicitation phase. Both therapies were associated with significant suppression of immediate type response, clinical appearance, dermal cell infiltration, reduced IL-4 production, and augmented IFN-gamma mRNA expression compared to placebo-treated mice. Additionally, increased number of Foxp3(+) regulatory T cells were observed in the skin sections in Ag85B treated mice. The results of this study suggest that Ag85B DNA vaccine is a potential therapy for Th2 type dermatitis.