To determine which endogenous HERV-K loci are responsible for the Env protein detectable on the surface of RA patient neutrophils, we isolated RNA from neutrophils from 18 RA patients and 10 healthy controls, followed by RNA-Seq and analysis for transcripts mapping to genomic loci annotated as HERV-K (or its synonyms). The gene discussed is ERVW-1; the disease is rheumatoid arthritis.