MEASUREMENT OF IGG, IGA AND IGE ANTIBODIES TO DERMATOPHAGOIDES-PTERONYSSINUS BY ANTIGEN-BINDING ASSAY, USING A PARTIALLY PURIFIED FRACTION OF MITE EXTRACT (F4P1)

Abstract

An extract of D. pteronyssinus culture was fractionated by chromatography on Sephadex G-100 and Pevikon block electrophoresis to obtain a partially purified allergen (F4P1). This preparation has a MW of 15-25,000 daltons, migrates slowly on electrophoresis and is colorless in solution. The skin-test reactivity of F4P1 was comparable to that of crude D. pteronyssinus extract. F4P1 was radiolabeled with 125I and used in an antigen-binding radioimmunoassay to measure Ig[immunoglobulin]G, IgA and IgE antibody (ab) to D. pteronyssinus. IgG ab was detected in serum from 32/34 (94%) mite-allergic persons and from 10/31 (30%) non-allergic persons. IgA ab and IgE ab were found in sera from 22/34 (65%) and 27/34 (79%) allergic persons, respectively. No IgA or IgE ab could be detected in sera from non-allergic persons. An excellent correlation was found between the radioallergosorbent technique (RAST) using crude D. pteronyssinus extract and IgE-binding activity (BA) for F4P1, (r = 0.94, P < 0.001). The antigen-binding assay for IgE BA was as sensitive as RAST but less sensitive than PK [Prausnitz-Kuestner] testing. There was a very good quantitative correlation between IgG BA and IgE BA (r = 0.84, P < 0.001). IgG BA rose in the serum of 3 patients treated with injections of D. pteronyssinus extract.