Participants were followed up for 12 months, and some required therapeutic biopsy for recurrent lesions.
Scarring was observed in all participants, with differences in severity related to lesion size and biopsy method.
The study was safe, with minimal adverse events, and immune landscape analysis of lesions showed a diverse inflammatory response.
Researchers conducted a groundbreaking study at the University of York to investigate Leishmania infection in humans. This study, known as LEISH_Challenge, enrolled 14 healthy volunteers who were exposed to sand flies carrying L. major, a parasite that causes cutaneous leishmaniasis. The volunteers, who were all of White ethnicity, were closely monitored for 12 months after exposure. The results revealed that 64% of all participants developed lesions after exposure, with 70% of those requiring no further treatment. Recurrences were observed in some participants, but cryotherapy proved effective in treating these cases.
The study also delved into the immune response within the lesions, displaying a complex network of immune cells and cytokines involved. Histologically, the lesions showed a dense lympho-histiocytic infiltration and varied degrees of parasitism. The discovery of different functional components within the lesions, such as myeloid cells, T cells, and fibroblasts, shed light on the intricate immune landscape of cutaneous leishmaniasis. Furthermore, advanced spatial transcriptomics revealed distinct subclusters within the lesion core, highlighting the intricate cellular interactions and pathways involved in the immune response to the parasite. This research provides valuable insights into the immune mechanisms at play during Leishmania infection and lays the groundwork for future studies in understanding and treating this disease.
