Assessment of intralesional cytokine profile of cutaneous leishmaniasis caused by Leishmania donovani in Sri Lanka.

Background: Cytokines play a vital role in the host immune response to infection by initiating the healing process and/or accelerating the progression of the disease in cutaneous leishmaniasis (CL). Very little evidence is available on cytokine profiles and their regulatory function in CL patients in Sri Lanka. The aim of this study was to determine the cytokine expression pattern of IFN-γ, IL-4, IL-11 and IL-12p40 in CL patients and in healthy volunteers. Patients with suspected CL lesions attending to the Dermatology Clinic at the Anuradhapura Teaching Hospital were included in the study. Reverse transcription real time polymerase chain reaction (real-time RT-PCR) was performed to determine the relative expression level of target cytokines. Expression levels were quantified by 2 equation.

Results: The expression of cytokines IFN-γ, IL-4, IL-11 and IL-12p40 were significantly higher in CL patients compared to healthy volunteers (p <  0.05). There was a significant association between the expression of IFN-γ and the duration of the lesion (p = 0.021). Wet CL lesions showed significantly higher expression of IL-4, IL-11 and IL-12p40 (p = 0.039, 0.018 and 0.021 respectively) compared to dry lesions. Papulo-nodular lesions showed significantly high expression of IFN-γ (p = 0.023). However, cytokine expression was not significantly associated with the number, size and the locations of lesions.

Conclusions: The expression levels of all cytokines tested in the present study were significantly (p <  0.05) high in CL patients. Th1 response (IFN-γ and IL-12p40) had higher expression levels compared to Th2 (IL-4) and IL-11 in CL patients.