Transplanted SS cells reproduce the human disease in mice. (A) Representative photograph of a mouse at 8 weeks after being transplanted with 2 million SS cells. (B) Hematoxylin and eosin (H&E) staining of a skin section of the same animal obtained at euthanasia. (C) FC analysis of the different organoids indicated the presence of SS infiltrates. (D) IHC analysis of liver sections to confirm FC data. (E) Clonality analysis by PCR analysis of SS from patient #23 and blood from 2 different mice transplanted with SS cells from the same patient. (F) IHC of the liver and spleen of a representative mouse transplanted with cells from patient #23. Note the high amounts of aberrant CD20⁺ B cells, already present in the patient, that infiltrate the organs in addition to the CD3⁺;CD4⁺;CD5⁺ SS population.