While no difference was observed regarding the number of interferon-gamma (IFN-γ)+ cells in lesions from pregnant compared to nonpregnant women with CL, interleukin-10 (IL-10) and IL-4 expression were approximately 3-times higher in lesions in pregnant women.
Here, we investigated whether IL-4/IL-13 signaling via the common IL-4 receptor alpha chain (IL-4Rα) on keratinocytes contributes to susceptibility during experimental CL.
Together, these results demonstrate that IL-4-producing and IL-4Rα-responsive B cells are critical in regulating and assisting early T helper dichotomy toward Th2 responses, which are detrimental in cutaneous leishmaniasis but beneficial in acute schistosomiasis.
The gene expression of cytokines/chemokines in skin biopsies from the CL group showed higher transcript levels of modulatory (IL10 and TGFB1), anti-inflammatory (IL4), and pro-inflammatory (TNF, IFNG, IL12B, CCL2, CCL3, CCL5, CXCL10) biomarkers in recent lesions than in late lesions.
Upregulation of IL-4 was correlated with a higher parasite burden in early lesions of CL, which may be involved in the pathogenesis of CL by inhibiting a protective immune response.
In conclusion, our results suggest that functional genetic variants in the IL-4 promoter could influence the risk of developing CL while the polymorphism in the first intron of the IFN-gamma gene might influence the progression of disease towards CCL.
The results clearly demonstrated a high level of IL-4 expression in nonhealing cases of CL and a low expression level of transcripts for IFN-gamma and IL-12.