Assessment of IgE allergen specificity among latex-allergic health care workers: review of IgE-binding components of various latex extracts

Identification of antigenic and allergenic natural rubber latex proteins by immunoblotting

Quantitation of proteins in finished natural rubber latex (NRL) products is essential in predicting their allergenic potential. The ASTM standard Modified Lowry method for measuring total protein content has been used for several years. Most recently, ASTM published a standard for more sensitive and more specific enzyme immunoassay for quantitation of antigenic NRL proteins. It is an ELISA inhibition assay, using rabbit anti NRL sera. Since the measurement of proteins in this method depends on recognition capacity of rabbit antibodies, the selection of an appropriate protein source for rabbit immunization is crucial for the accuracy of such test. In this study, we evaluated the composition of NRL proteins from ammoniated (AL) and nonammoniated (NAL) raw latex and from finished NRL products, and compared the effectiveness of sera from rabbits immunized with NRL proteins, to react with those extracts. Immune rabbit sera were analyzed by immunoblotting against extracts of several samples of AL, NAL, and glove proteins. In the NAL extracts, we identified 26-28 protein bands by SDS-PAGE. AL samples had between 6 and 9 bands with a great variation in the band positions among the samples. The Western blot analysis showed that anti-AL rabbit serum reacted with 4-9 protein bands in various AL extracts. The highest intensity of reaction was observed with the extract used to immunize the rabbits. Similar reaction was observed with anti-NAL serum. However, when the antisera were blotted against NAL extracts, anti-NAL serum reacted more strongly and with a larger number of proteins than anti-AL serum. In summary, anti-NAL serum recognized an equal number of proteins in AL extract as anti-AL serum. However, anti-AL serum recognized fewer protein molecules in NAL extract than anti-NAL serum. Our findings suggest that NAL extract contains more individual proteins than other extracts, and sera from rabbits immunized with this antigen have a greater capacity to react with a wide spectrum of NRL proteins. This finding may be helpful in selecting the representative reference antigen and antiserum for further efforts in NRL protein quantitation.

Latex aeroallergen quantification in hospitals of Moscow, Russia

BACKGROUND

Health care workers (HCWs) who use latex gloves regularly are at a significant risk for developing allergic sensitization to natural rubber latex (NRL) proteins. The airborne route of exposure presents a hazard for sensitization and subsequent allergic symptoms.

OBJECTIVE

The purpose of this study was to measure the content of the NRL proteins in the air of work areas (laboratories, treatment rooms, operating rooms, examination rooms, and dentist's treatment rooms) in eight Moscow hospitals where the employees used powdered latex gloves.

METHODS

The air samples were collected by a volumetric filtration method using a static air sampler at a flow rate of 3 L/second. Airborne particles were collected onto polytetrafluoroethylene filters rated 99.9% efficient at 0.3 microm. The NRL allergens were extracted from the air filter samples in phosphate-buffered saline and quantified by an inhibition immunoassay using a five-person pool of sera containing latex-specific human immunoglobulin E.

RESULTS

The airborne latex allergen concentrations in 11 areas (including positive control) where latex gloves were used varied from 5 to 26 ng/m3. Conversely, in 12 areas where latex gloves were seldom used or where powdered-free latex gloves were used allergen levels were not detectable (including two negative controls). The highest concentration of latex allergen (26 ng/m3) was found in an examination room of a gynecology department. Low and moderate concentrations were detected in most operating rooms, and low concentrations in the laboratories and treatment rooms.

CONCLUSIONS

This study indicates that, in general, the airborne NRL concentrations in the work areas of Moscow hospitals are rather low compared with NRL concentrations reported from American hospitals and are dependent on the intensity of latex glove usage.