FLT3LG and hydrops fetalis: In immortalized human fibroblasts (HF), the Fl-PHF10i pSLIK constructs had a minor increase in expression without Dox (also known as “leakage”) (Figure 4F, recombinant isoforms before induction are denoted with arrows), but the activation of PHF10i expression increased transcription 30-fold (Figure 4G).