Introduction: In leprosy, immune system mediators that regulate the infectious process act in a complex manner and can lead to several clinical outcomes. To understand the behavior of these mediators we quantified the expression of annexin-A1 (ANXA1) in the peripheral blood and plasma as well as tissue leukocytes in all clinical forms of leprosy and compared with healthy controls. Methods: Seventy healthy controls and 70 patients with leprosy, tuberculoid (TT) (n = 13), borderline tuberculoid (BT) (n = 15), borderline borderline (BB) (n = 13), borderline lepromatous (BL) (n = 15), and lepromatous leprosy (LL) (n = 14), were selected. Phenotyping of the lymphocyte cells and the intracellular expression of ANXA1 in leukocytes was performed by immunofluorescence. Plasma protein levels were determined by enzyme-linked immunosorbent assay. Results: Histiocytes and CD4 + and CD8 + T cells in the skin of BL and LL patients had higher ANXA1 expression. ANXA1 expression was also high in circulating polymorphonuclear, monocytes, and CD4 + and CD8 + T cells in the blood of LL patients compared to those of TT, BT, BB, and BL patients, and these levels were similar to those in healthy controls. Plasma ANXA1 levels indicate an increase in paracrine release in patients with LL. Conclusions: The data indicate that ANXA1 expression is enhanced in the leukocytes and plasma of patients with LL, and may contribute to the inhibition of leukocyte action, leading to inadequate functioning of the immune system and thus contributing to the spread of M. leprae infection.

Introduction: Currently, there are no laboratory tests or sensitive and specific molecular markers for the early diagnosis of leprosy. The aim of this study was to analyze the clinical characteristics of patients with leprosy and investigate their immunological profile, comparing this with the type of lesion and the presence or absence of a Bacillus Calmette-Guérin (BCG) vaccination scar. Methods: Statistical analyzes were performed by employing comparative tests (Pearson´s chi-square) to evaluate the variables in different clinical forms, considering significance at the 5% level. Results: The study identified a predominance of lepromatous leprosy (26.9%) in patients aged between 34-53 years. Caucasians predominantly had borderline tuberculoid (BT) clinical forms (42%); a predominance of males with borderline lepromatous (19%) and lepromatous leprosy (26.9%) forms was observed; and the presence of BCG vaccination scars (27.5%) and lower limb nerves were more affected (38%) predominantly in the BT clinical form. Significant differences were identified, which included hypochromic lesions predominantly in the BT clinical form (24%); diffuse-type lesions predominantly in the tuberculoid (TT) clinical form (28%); ill-defined lesion border dominance in lepromatous leprosy (LL) clinical forms (30%); an irregular lesion limit predominantly in LL clinical forms (32%); and a predominant Th1 immune response in the BT clinical form (41.7%). Conclusions: The evaluation of the immunological profile in leprosy patients may contribute to the more detailed diagnosis and possibly better characterization of the prognosis for these individuals.