813 Total IgE determinations: Comparison of results obtained by immulite and CAP system

Abstract

Determination of total IgE daily pratiee, is one of first in vitro steps to support the diagnosis of Atopy. Previously the authors showed that the results of total lgE obtained by IRMA (Tecam 8000) and Immulite were of r=0,974 until 300 I.U. and r=0,87 for values between 300 and 600 I.U. Immulite total lgE is a solid phase, two site ehemiluminescente enzyme immunometric assay. The solid phase is a polystyrene bead coated with polyclonal antibody spectre for lgE. CAP system consists of a solid phase encased a capsule. The solid phase is a flexible hidrophilic carter polymer (CNBr-activated cellulose derivative). The aim of the study was to compare the results obtained by lmmulite using 68 serum samples with doseable IgE, with a wide range of values. The results show that the correlation between the two tests is r = 0,92162. Conclusions: The results show that there is a highly correlation between the two tests, validating the use of Irnmulite for total lgE determinations until the limit of 600 I.U. Studies must be done to determine accuracy for values higher than 600 I.U., where dilutions must be made, comparing the results with other already established methods. 815 Intravenous administration of a potential T cell toleragenic peptide to cat sensitive patients. PS Norman MD. AMG Pasatiemvo MD. PS Creticos MD, CF Nicodemus MD. NH Jones. P-hD. LM Lichtenstein MD PhD. M L Gef te r PhD. Bal t imore MD, W a l t h a m M A . More than 400 patients have safely received subcutaneous injections of a mix of 2 peptides selected to contain dominant T cell epitupes for cat allergen (ALLERVAX® Cat). We wished to explme the effect of inlravenous administration of one of the peptides. In cat allergic patients we assessed the safety and immune response of IPC-2, a 27 amino acid peptide contained chain 1 of Fel d 1. We selected 8 patients sensitive to cat by history and skin test to cat extract but skin negative to the peptide. We administered six successive iv infusions once a week of 2.5, 7.5, 75, 250, 750 and 1500 lag of IPC-2 dissolved normal saline 20 rain by pump. There were no inunedlate allergic responses. One patient experienced self limited mild chest tightness and wheezing of similar intensity several hours post infusion at each visit. Six patients had late phase skin responses to cat extract before u ment (Mean Y~ diameters=1025:20 mm). Post treatment, thes, ,ere reduced size 5 patients and unchanged I patient (Mean ~ diameters=43+97 nun, p=0.05). Immediate skin responses to cat extract and mean values for IgE and IgG to Fel d 1 were not changed but one patient, despite a reduction the late phase skin response, there was a 40 fold rise IgE and a 2 fold rise IgG to Fel d 1. No one developed IgE or IgG antibodies to IPC-2. Intravenous administration oftbe peptide was well tolerated, induced little change immediate skin tests or antibodies but suppressed the late phase inflammatory skin responses presumably mediated by T cells. An additional placebo controlled study is ongoing that compares subcutaneous doses of IPC-I and IPC-2 separately with a combination of the two (ALLERVAX® Cat).