Methods for identifying and isolating CD8 T cells that produce interleukin-13 upon activation are provided. The present methods leverage one or more newly-identified biomarkers to identify such CD8 T cells and, in certain cases, sort the same. Certain methods comprise obtaining a sample from a mammal, quantifying a level of expression of one or more biomarkers therein, and determining if the level of expression is elevated as compared, wherein an elevated expression level is indicative of an active disease state. Antisera and antibodies are also provided. In particular, an anti-C10orf128 antiserum formulated against a particular peptide is provided, such anti-C10orf128 antiserum characterized in that it identifies a subset of CD8 T cells that produce interleukin-13 upon activation.