Immunological biomarkers and their role in the diagnosis and prognosis of leishmaniasis: A case-control study.

Background: Different kinds of leishmaniasis can be distinguished based on the range and complexity of clinical presentations, which can vary from asymptomatic infection to severe illness that greatly affects one's quality of life.

Aims of the study: Determining the relationship between inflammatory cytokines and the severity of leishmaniasis.

Methodology: A case-control study comprising 150 patients diagnosed with cutaneous leishmaniasis (75 males and 75 females) with 50 healthy controls. The individuals in question ranged in age from 35 to 45. The study was carried out at Nasiriyah General Hospital and Al-Habobbi Teaching Hospital between January 1, 2024, and August 1, 2024. Inclusion criteria required patients aged 35-45 years, with clinically confirmed leishmaniasis and positive serological results, who provided consent for participation. Exclusion criteria included individuals with immunological disorders and pregnant people. The infected group was clinically evaluated to exclude other infections or inflammatory conditions that could affect cytokine levels. Patients were categorized into mild, moderate, and severe leishmaniasis based on clinical criteria, including lesion size, number, complications, and infection duration, following established guidelines. The serum was isolated using centrifugation and preserved at a temperature of -20°C to quantify the concentrations of anti-Leishmania antibodies, interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), and CRP using the enzyme-linked immunosorbent assay (ELISA) method. The ELISA kits used to measure cytokine levels and antibody titers were sourced from Bio-Techne, an American company.

Results: The results showed nonstatistically significant differences in mean age or gender distribution between patients and healthy controls. However, fever was more common in patients, and the severity of the disease was classified into three grades. Levels of antibodies, IFN-γ, tumor necrosis factor, IL-10, and C-reactive protein were also significantly higher in patients than in healthy controls, suggesting an association with leishmaniasis infection.

Conclusions: The results confirm the relationship between levels of antibodies and immune complexes, such as IFN-γ and TNF-α, with the severity of leishmaniasis infection. These high levels indicate an intense immune response, reflecting the body's inflammatory reaction to the infection.