A cDNA clone is provided which encodes a human receptor for the Fc portion of immunoglobulin G. Soluble forms of the receptor may be useful in treating disorders associated with excessive immunoglobulin G production. Cells expressing membrane-bound forms of the receptor are useful in assays for immune complexes, elevated levels of which are associated with numerous disease states, including systemic lupus erythematosus (SLE) and rheumatoid arthritis.