The invention provides uses of polypeptides of soluble BR43x2 class receptors, and sequences substantially homologous thereto or orthologs thereof, as well as antibodies that bind to BR43x2 class soluble receptors in the manufacture of medicaments for inhibiting ztnf4 activity. The uses of the invention also extend to manufacture of medicaments for treating autoimmune diseases, such as systemic lupus erythematosus, myasthenia gravis, multiple sclerosis and rheumatoid arthritis, amongst others. The invention provides uses of polypeptides of soluble BR43x2 class receptors, and sequences substantially homologous thereto or orthologs thereof, as well as antibodies that bind to BR43x2 class soluble receptors in the manufacture of medicaments for inhibiting ztnf4 activity. The uses of the invention also extend to manufacture of medicaments for treating autoimmune diseases, such as systemic lupus erythematosus, myasthenia gravis, multiple sclerosis and rheumatoid arthritis, amongst others.