Interleukin-10 muteins and other interleukin-10 - related molecules are described, as well as methods of identifying interleukin-10 muteins and other interleukin-10 - related molecules. Also described herein are modifications of the foregoing, which modifications may enhance a property (e.g., half-life) of the muteins or other molecules compared to human interleukin-10. Particular interleukin-10 muteins and related molecules have comparable immunogenicity to human interleukin-10 and/or bioactivity at least comparable to human interleukin-10. Pharmaceutical compositions and methods of use are also described herein.