Center for Computational Immunology, Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, NC 27705, USA. feng.feng@duke.edu|Center for Computational Immunology, Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, NC 27705, USA. feng.feng@duke.edu|Center for Computational Immunology, Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, NC 27705, USA. feng.feng@duke.edu