A study comparing the genetic expression profile in tuberculoid and lepromatous lesions showed that the multibacillary disease was associated with an increase in the plasma cell (CD138+) frequency and an increase in the expression of IL-5 and IgM in the lesions, consistent with the fact that lepromatous leprosy is closer to the Th2 pole.25 Here, IL5 is linked to lepromatous leprosy.