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Background As a strong inducer of IgE antibodies to substituted ammonium ion epitopes ( QAI), pholcodine ( PHO) is a postulated cause of allergic anaphylaxis to neuromuscular blocking agents ( NMBAs). Three years after withdrawal of PHO in Norway, a significant reduction in IgE sensitization and anaphylaxis reporting was seen. Objective Six-year follow-up study on the effects of PHO withdrawal on IgE sensitization and anaphylaxis reporting. Methods From 650 acute consecutive reports (2005-2013) to the Norwegian Network for Anaphylaxis under Anaesthesia ( NARA), total number of reports on suspected anaphylactic reactions, number of reactions where NMBAs were administered, number of reactions where serum IgE antibodies (≥0.35 kUA/l) to suxamethonium ( SUX) and PHO were present at time of reaction and anaphylaxis severity grades were retrieved. In addition, NMBA sales and prevalence of IgE sensitization to PHO and SUX among 'allergics' were monitored. Results From baseline period P0 ( PHO on the market) through the first (P1) and second (P2), three-year periods after withdrawal, significant falls in total reports ( P < 0.001) and reports with IgE antibodies to PHO ( P = 0.008) and SUX ( P = 0.001) at time of reaction were found. Total NMBA sales in P2 were 83% of P0, and SUX and rocuronium ( ROC) together made up 86% of sales throughout the study. Five NMBA-related anaphylactic deaths occurred during P0 and P1 and, however, none during P2. Prevalence of IgE sensitization to SUX in 'allergics' fell to 0% at 4 and 5 years after withdrawal. Conclusions Six years after PHO withdrawal, the Norwegian population has become significantly less IgE-sensitized and clinically more tolerant to NMBAs. [ABSTRACT FROM AUTHOR]

Visualization by autoradiography of specific IgE binding in crossed radioimmunoelectrophoresis (CRIE) and other 125-immunoautoradiography (IAR) techniques is done in two different ways: either by traditional direct autoradiography (D-ARG), where the film is exposed to the 125I-anti-lgE incubated sample at room temperature, or by indirect autoradiography (ID-ARG), applying intensifying screen, low-temperature exposure and, eventually, pre-exposure. This study confirmed that D-ARG provided the benefits of simplicity and better image resolution with the disadvantage of prolonged exposure periods. ID-ARG reduced the exposures needed to produce film image densities of 0.01 and 0.1 A540 nm (i.e. autoradiographic sensitivity (ARσ) and autoradiographic speed (ARs)) to 1/18 and 1/55 respectively of the corresponding exposures in D-ARG. The lowest detection limits for 125I in 24 h were 1.2 cpm mm-2 with the indirect and 6.8 cpm mm-2 with the direct systems investigated. The major drawbacks of ID-ARG were inferior image resolution and higher background levels, especially when pre-exposure was included. [ABSTRACT FROM AUTHOR]

The CD-calcium binding loop of Allergen M encompasses the two homologous tetrapeptides Asp-Glu-Asp-Lys and Asp-Glu-Leu-Lys. These tetrapeptides were recently suggested to be mutually critical for the immunological specificity of this region. To obtain evidence of the validity of this hypothesis, four peptide analogues encompassing these tetrapeptides at the termini were produced by manual solid-phase peptide synthesis. The structures of these peptides were ascertained by amino acid analyses and end-group sequence determination. The crude preparations were prepared by high-performance liquid chromatography and high-voltage electrophoresis. The immunological reactivity was investigated by using the preliminary purified peptides in the IgE and IgG test systems used. The results of radioallergosorbent test inhibition showed that all the synthetic peptides encompassing a minimum of two of the tetrapeptides have the capacity to bind specific IgE of the serum pool. The composition and sequence of the six spacer amino acids between these tetrapeptides were of no importance for the acitivity. The highest inhibition percentage was obtained by the peptides derived from the primary structure of Allergen M. No activity was found for the control peptides synthesized under identical conditions. Similar results were shown by PK tests, using two cod-allergic sera and two recipients. In the IgG test system, all the four peptides containing the two terminal tetrapeptides showed an antigenic reactivity. They deflected allergen M line in rocket line immunoelectrophoresis. No deflection was given by the control peptides or proteins used. We conclude that the immunological reactivity of region 41-64 of allergen M is determined by 3 homologous tetrapeptides, repeated in three sites interspaced by six amino acids in a segment of 24 residues. [ABSTRACT FROM AUTHOR]

A peptide with the sequence of the second calcium-binding loop (EF loop) of cod Allergen M was synthesized by automatic solid-phase technique. The synthetic peptide corresponded to residues 88-103 of the known primary structure of Allergen M. The immunohemical reactivity of this loop, previously demonstrated for the overlapping enzymic fragments, was confirmed by using the synthetic preparation. The purified hexadecapeptide was shown to bind specifically to reaginic IgE from sera of cod-allergie individuals, in both in vivo and in vitro test systems. It could also bind rabbit anti-Allergen M. as shown by rocket line immunoelectrophoresis and quantitative precipitation inhibition techniques. The findings emphasized that the immunological reactivity of the synthetic peptide (88-103) was compatible with a monovalent haptenic function; blocking and not eliciting allergic reactions. [ABSTRACT FROM AUTHOR]