Eosinophil and B-cell dynamics in the milky spots from Schistosoma mansoni-infected mice: comparison with spleen and bone marrow, and extramedullary eosinopoiesis.

This article focuses on the characterization of milky spots (MS)—lymphomyeloid structures in the omentum—and their immune cell dynamics during Schistosoma mansoni infection in a murine model. The study reveals that MS, primarily composed of B lymphocytes (notably B1a and B1b subsets), T lymphocytes, macrophages, and eosinophils, undergo significant activation and cellular profile changes throughout infection, including local eosinopoiesis and expansion of B1b cells. Comparisons with spleen and bone marrow show distinct temporal patterns of eosinophil and B-cell populations, reflecting shifts in immune responses from Th1 to Th2 dominance and back toward balance. The findings highlight MS as a central lymphoid organ contributing to cavity immunity and systemic hematopoietic modulation during parasitic infection, emphasizing their role in coordinating immune responses that control infection and limit tissue damage.