Tissue Expression of NGF in Skin Lesions of HIV-Coinfected and Non-Coinfected Leprosy Patients and Its Relationship with Leprosy Neural Damage

Leprosy remains a significant public health issue, particularly due to its neuropathic consequences, which affect sensory, motor, and autonomic functions, leading to severe disabilities. HIV/AIDS, another major public health concern, overlaps geographically with leprosy and is also associated with peripheral neuropathies, complicating the management of co-infected patients. Understanding how Nerve Growth Factor (NGF) is regulated in leprosy and HIV-leprosy co-infection may contribute to immunomodulatory treatments and neuroimmune response control. A cross-sectional study evaluated NGF tissue expression using immunohistochemistry in 47 HIV/leprosy co-infected patients and 61 leprosy-only patients. The co-infected group had a higher incidence of neuritis (40.4%) and a prevalence of exclusively reversal reactions. However, the occurrence of neuritis was not associated with higher expression of NGF in the tissue. Leprosy reactions were more prevalent in non-co-infected patients with multibacillary forms (50%). Multibacillary forms in both groups of patients showed higher cellular expression of NGF, with a greater tendency for higher NGF expression in non-co-infected multibacillary patients (<i>p</i> = 0.0021), suggesting impairment in the immune response involved in the tissue expression of neurotrophins in the co-infected group. Overall, co-infection with HIV did not influence the increase in NGF in the lesions of leprosy patients compared with patients with leprosy alone.