Counterimmunoelectrophoresis with serum prediffusion: an improved method for the detection and identification of antibodies against extractable nuclear and cytoplasmic antigens.

In the technique of counterimmunoelectrophoresis (CIE) with serum prediffusion (SPD) serum is allowed to diffuse freely into the gel before pouring the antigenic extract in its trough (or wells) and starting the electrophoresis. Both the immunoprecipitations and the interactions with reference sera are strongly intensified by SPD, leading to higher sensitivity and specificity for the detection of anti-SSA/Ro, anti-SSB/La, anti-U1RNP, anti-Sm, anti-Jo1 and even anti-Scl-70 antibodies. We found that the optimal SPD time was 2 h. To evaluate the relevance of SPD for the clinical laboratory, 92 antinuclear antibody (ANA) positive sera were tested on CIE without SPD and with 2 h SPD in identification tests with SSA/Ro, SSB/La, Sm, U1RNP and Jo1 reference sera (rsa). The precipitation lines and their interactions were evaluated by three independent observers. It was observed that SPD considerably improved the efficiency of CIE for antibody identification. The mechanisms underlying the intensification of the precipitation lines by SPD are discussed as are the characteristics of the CIE in comparison with other test systems such as the enzyme linked immunosorbent assay (ELISA) and immunoblot.

Allergenic proteins in different brands of latex and synthetic medical examination gloves.

The steady increase in anaphylactic reactions to latex medical gloves has raised increasing awareness in the medical community. Even gloves claimed to be hypo-allergenic still may contain substantial amounts of IgE-binding proteins. We have studied non-powdered latex and synthetic examination glove extracts for their allergenicity using the immunoblot technique. Protein levels varied considerably among glove extracts and the amount did not always correlate with the presence of allergenic proteins. IgE binding proteins were found in 2 of the 7 powder-free latex glove brands. Synthetic glove extracts did not contain allergens. The study demonstrates that immunoblot analysis is a useful technique in order to select gloves with a minimal risk to raise IgE antibodies.