Leishmaniasis is caused by certain intracellular Leishmania species and is common in the tropics, where it exhibits a wide range of clinical manifestations. Both cellular and humoral immunological responses play crucial roles in disease progression. This study identified the fundamental role of B lymphocytes during the progression of leishmaniasis in human hosts. A cross-sectional study of patients with cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) from different parts of Iraq was conducted, and their respective serum IgE levels were measured before any treatment was administered. Sandwich ELISA was used for quantitative measurement of IgE in CL, VL, and control subjects. The results revealed a higher level of IgE concentration in the cutaneous patients (p<0.05) when compared with the healthy control group (53.21±9.1, 9.37±1.7, respectively). No significant IgE variance was observed between the visceral patients (13.2 ± 7.3) and controls. Interestingly, a significant difference (p<0.00001) in IgE levels was detected between the cutaneous and visceral patients. Higher IgE levels measured in patients with CL compared to those with VL may provide insight into the polarised T helper 2 immune response within active skin lesions. These findings provide vital insights into the humoral responses against the two forms of leishmaniasis.
