Abstract: A method for the treatment of immune system disorders in humans by administration of pp14; derivatives, fragments, or subunits of pp14; or monoclonal antibodies thereto. The method may be used to treat allergic disorders, autoimmune disorders, inflammatory disorders, lymphoproliferation disorders, and neoplastic disorders. Monoclonal antibodies to pp14, and the hybridoma cell lines which produce them. A method for the detection and quantitation of pp14 using monoclonal antibodies thereto, as well as a method for the purification of pp14 using an affinity or immuno-precipitation reaction.