Overall, our study provides novel insights into the immunological aspects of MASLD and HCC, emphasizing the involvement of IgM+IgD+ Bregs, CD19+B220+CD27+IgD+ NSw MBCs and CD19+B220+CD138+ PBs with immunosuppressive characteristics in disease progression. The gene discussed is CD40LG; the disease is metabolic dysfunction-associated steatotic liver disease.