John W. Yunginger

Quantification of occupational latex aeroallergens in a medical center

To determine the quantity, variability, and mean aerodynamic diameter of latex aeroallergens in a large medical center, we collected air samples from work sites by using area and personal breathing zone air samplers, and we measured latex allergens by an inhibition assay with IgE antibodies from latex-sensitive individuals. Latex aeroallergen concentrations in 11 areas where powdered latex gloves were frequently used ranged from 13 to 208 ng/m3, and in areas where powdered latex gloves were never or seldom used, concentrations ranged from 0.3 to 1.8 ng/m3. Installation and use of a laminar flow glove changing station in one work area did not reduce latex aeroallergen levels. Large quantities of allergen were recovered from used laboratory coats and anesthesia scrub suits and from laboratory surfaces. Latex allergen concentrations in personal breathing zone samplers worn by health care workers in areas where powdered gloves were frequently used ranged from 8 to 974 ng/m3. Exposure likely occurs when gloves are changed and as a result of resuspension from reservoirs of powder in the room and clothing. Latex allergens were found in all particle sizes but were predominant in particles greater than 7 microns in mass median aerodynamic diameter. Results of electrophoretic immunoblotting showed that the aeroallergens are primarily the higher molecular mass components of the latex glove proteins. Measures to control exposure can be monitored by both area and personal air sampling with this immunochemical approach. Use of gloves with low allergen content or powder-free gloves appears to be more effective than use of a laminar flow glove changing station in reducing aeroallergen levels.

Allergic rhinitis in Rochester, Minnesota residents with asthma: Frequency and impact on health care charges ☆ ☆☆ ★

BACKGROUNDnAsthma is a common and costly condition. Concomitant asthma and allergic rhinitis (AR) have been shown to increase the medication costs for people with asthma. No studies have compared medical care costs of those with and without concomitant AR.nnnOBJECTIVESnWe sought to determine the prevalence and incremental medical care costs of concomitant AR.nnnMETHODSnFor each member of a population-based asthma cohort, we used all their medical charts within Olmsted County to record age at first diagnosis of asthma; the presence and age of any diagnosis of AR; and the total, ambulatory, and respiratory care-related costs of medical care. Costs were compared for age- and sex-specific strata of people with asthma who did and did not have AR.nnnRESULTSnAR was most commonly diagnosed in people whose asthma was diagnosed before age 25 (prevalence of 59%) and uncommonly diagnosed in anyone after age 40 (prevalence <15%). Yearly medical care charges were on average 46% higher for those with asthma and concomitant AR than for persons with asthma alone, controlling for age and sex. We were unable to assess the impact of treatment of AR on medical care charges.nnnCONCLUSIONSnPhysicians should consider the diagnosis of AR (prevalence >50%) in all symptomatic children and young adults with asthma. Further evaluation is necessary to evaluate the ability of treatment to decrease the incremental costs of AR in persons with asthma.

Attained adult height after childhood asthma: Effect of glucocorticoid therapy

BACKGROUNDnAlthough oral and inhaled glucocorticoid therapy may impair growth in children with asthma, the effect of glucocorticoid therapy and asthma on attained adult height has not been extensively studied in representative children in the community.nnnOBJECTIVESnThe study was designed to compare the attained adult height of children with asthma with the attained adult height of nonasthmatic children and to compare the attained adult height of asthmatic children treated with glucocorticoids with the attained adult height of asthmatic children who did not receive glucocorticoids.nnnMETHODSnResidents of Rochester, Minnesota, with onset of asthma from 1964 to 1987 and age- and sex-matched non-asthmatic residents of Rochester were studied. Glucocorticoid exposure was assessed from medical records. The mean of 5 stadiometer measurements of adult height, adjusted for sex and parental height, was analyzed.nnnRESULTSnOne hundred fifty-three patients with asthma (mean age at onset, 6.1 +/- 4.8 years) and 153 age- and sex-matched nonasthmatic subjects were studied. Adult height of patients with asthma (mean age at measurement, 25.7 +/- 5.2 years) was not significantly different from the adult height of non-asthmatic subjects; the overall difference, adjusted for mid-parental height, was -0.20 cm (95% confidence interval from -0.27 to 1.64). The adult height of asthmatic children treated with glucocorticoids was not significantly different from the adult height of patients with asthma not treated with glucocorticoids; the difference after adjusting for mid-parental height was -0.2 cm (95% confidence interval from -0.1 to 0.6).nnnCONCLUSIONSnWe conclude that the attained adult height of patients with asthma is not different from the adult height of age- and sex-matched nonasthmatic subjects and that the attained adult height of asthmatic children treated with glucocorticoids is not significantly different from the adult height of children not treated with glucocorticoids.

A prospective, controlled study showing that rubber gloves are the major contributor to latex aeroallergen levels in the operating room☆☆☆★★★

BACKGROUNDnAlthough protocols have been published for reducing natural rubber latex exposure in medical environments, there are no objective data documenting their effectiveness.nnnOBJECTIVEnWe prospectively studied the impact of a single intervention, substitution of low-allergen-containing latex gloves for high-allergen-containing latex gloves, on latex aeroallergen levels in a single operating room (OR).nnnMETHODSnWe sampled OR air on 52 consecutive days, including 33 surgery days and 19 nonsurgery days. On each surgery day all personnel wore either high-allergen gloves (n = 18 days) or low-allergen gloves (n = 15 days). Latex aeroallergen levels (in nanograms per cubic meter) and extractable latex glove allergen contents (in allergen units per milliliter) were measured by inhibition immunoassays. An on-site study monitor recorded the number of gloves used, the total time spent by all patients in the OR each day (OR time), and the total time of all procedures for each day (operating procedure time).nnnRESULTSnLatex aeroallergen levels during low-allergen glove use days (mean, 1.1 ng/m3; median, 0.9 ng/m3; range, 0.1 to 3.5 ng/m3) were significantly lower than on high-allergen glove use days (mean, 13.7 ng/m3; median, 7.7 ng/m3; range, 2.2 to 56.4 ng/m3) (p < 0.001) but not significantly different from that on nonsurgery days (mean, 0.6 ng/m3; median, 0.3 ng/m3; range, 0.1 to 3.6 ng/m3). Latex aeroallergen levels were strongly correlated with the total number of gloves used on designated high-allergen glove days (r = 0.66, p = 0.003). There was no appreciable day-to-day carryover of latex aeroallergen.nnnCONCLUSIONSnThe substitution of low-allergen-containing latex gloves for high-allergen-containing latex gloves can reduce levels of latex aeroallergen by more than 10-fold in an OR environment.

Incidence of latex sensitization among latex glove users

BACKGROUNDnAlthough there are several reports of the prevalence of latex sensitization among health care workers, the incidence of sensitization is unknown.nnnOBJECTIVEnThe objective of this study was to estimate the incidence of sensitization among latex glove users at a hospital in Hamilton, Ontario, Canada.nnnMETHODSnWorkers with negative results to the skin test at baseline were followed prospectively over 1 year, some wearing powdered gloves and others using powder-free gloves. They were reevaluated in 1995 with a questionnaire and skin prick test (SPT) sensitivity to latex reagents, three common inhalants, and six foods. A conversion was defined as a (new) latex SPT with wheal diameter at least 4 mm greater than saline control. Glove extracts were assayed for antigenic protein, and air samples were obtained to estimate exposure to airborne latex protein.nnnRESULTSnDuring powdered glove use, personal exposures ranged from 5 to 616 ng/m3, whereas during powder-free glove use, all but two results for air samples were below the limit of detection (about 0.1 ng/m3). During the study period, the protein concentration in the powdered gloves, initially mean 557 microg/gm of sample, declined at a rate of 295 microg/gm per year (p < 0.0001). Of the 1075 SPT-negative participants at baseline, 479 were working in eligible wards, and of these, 435 (91%) participated in follow-up, 227 using powder-free gloves and 208 using powdered gloves. We identified four conversions, two (1.0%) in the powdered glove group and two (0.9%) in the powder-free group. The two participants using powdered gloves were the only converters who were symptomatic. The significance of skin test conversions identified in the powder-free group, both asymptomatic patients, is unclear. The limitations of the study are discussed, including the limited power, the declines in latex protein concentrations, and the possibility of information (observer) bias.nnnCONCLUSIONnTo our knowledge, this represents the first reported estimate (about 1%) of incidence of sensitization in hospital personnel using latex gloves.

Occupational latex exposure: characteristics of contact and systemic reactions in 47 workers

BACKGROUNDnRecent reports have noted an apparent increase in the prevalence of natural rubber latex (NRL) allergy among workers with occupational latex exposure (OLE). The risk factors for and the natural history of NRL allergy in this population are not well delineated, and the utility and comparability of immunoassays as confirmatory testing are unclear.nnnMETHODSnSerum samples and medical histories were obtained from 47 symptomatic workers with OLE, from nine other individuals with a history consistent with NRL allergy, and from 10 atopic asymptomatic NRL-exposed control subjects. Sera were coded and analyzed in a blinded manner for latex-specific IgE, using a variety of antigen sources, including ammoniated and nonammoniated raw latex preparations and three finished glove preparations.nnnRESULTSnRisk factors for the latex allergy in workers with OLE appear to include a history of atopy or preexisting dermatitis involving the hands. In this population, NRL allergy is commonly preceded by latex glove-associated contact dermatitis. Serologic testing confirmed the suspected diagnosis in 62% of workers (15 of 24) with systemic symptoms but was only positive in 27% of workers (4 of 15) with symptoms limited to contact urticaria.nnnCONCLUSIONSnThe appearance of a latex glove-associated contact rash may precede the development of NRL allergy, particularly in atopic persons. Workers at risk should be advised to use alternate types and brands of latex gloves or to switch to nonlatex gloves entirely.

Seasonal changes in serum and nasal IgE concentrations

Abstract Sequential changes in serum and nasal IgE concentrations were examined in both hyposensitized and nonhyposensitized patients with ragweed hay fever. Concentrations as low as 0.1 ng. per milliliter of IgE in nasal washings could be measured directly by a modification of the double antibody radioimmunoassay. Serum IgE levels rose during the ragweed pollination season in all allergic groups, with the hyposensitized patients showing a more sustained elevation of serum IgE. Nasal IgE concentrations in allergic subjects were consistently elevated as compared to nonallergic subjects. The IgE content of nasal washings varied directly with total protein content. Because the protein content in turn varied widely from patient to patient, nasal IgE concentrations were expressed in terms of an IgE:total protein ratio (IgETP). Nasal IgETP rose in most allergic patients during the ragweed pollination season, with the hyposensitized patients again showing a more sustained elevation. There was a strong correlation between nasal IgETP and serum IgE in the allergic patients. The results are interpreted in terms of the local production of IgE by cells in the nasal tissues and are consistent with the hypothesis that IgE, like IgA, is a secretory immunoglobulin.

Clinical and immunologic follow-up of patients who stop venom immunotherapy

We prospectively studied 51 self-selected Hymenoptera sting-sensitive patients to determine (1) whether a minimal or optimal duration for venom immunotherapy (VIT) exists and (2) whether clinical or immunologic parameters exist that are predictive of clinical immunity after VIT was stopped. After 2 to 10 years of VIT, all patients had deliberate sting challenges (DSCs) from live insects. If DSCs were tolerated, patients voluntarily stopped VIT and returned annually for repeat venom skin tests (VSTs) and DSCs. In most patients, it was possible to monitor VST and venom-specific antibody (Ab) levels before and after VIT was stopped. One-year after VIT, VST and venom-specific IgE and IgG Ab level results were variable; 49 patients tolerated DSC, whereas two patients exhibited generalized reactions. These two patients had pre-VIT histories of grade IV field-sting reactions and had received VIT for 2 years and 4 years, respectively. The short-term (1 year) risk of recurrence of clinical allergy to stings after VIT was higher in patients who had experienced grade IV field-sting reactions before VIT versus patients experiencing grade I to III reactions before VIT (2/15, 13% versus 0/36, 0%) and higher in patients who had received VIT for less than 5 years versus patients who received VIT for 5 or more years (2/20, 10% versus 0/31, 0%). We suggest that VIT should be continued for 5 years in patients with pre-VIT field-sting reactions of grade IV severity. VST and venom-specific Ab results do not reliably predict the outcome of DSC or the subsequent clinical course in individual patients stopping VIT.

Immunoassay of peanut allergens in food-processing materials and finished foods*

To quantitate trace amounts of peanut allergens in food-processing materials and finished foods, we established a solid-phase radioimmunoassay inhibition using pooled sera from five peanut-sensitive subjects and a roasted peanut-meal extract covalently linked to polyacrylamide beads. Test samples were extracted, dialyzed, lyophilized, and reconstituted at 10 to 225 mg of dry weight per milliliter concentrations. The peanut-allergen content of test samples was expressed relative to a reference extract of roasted peanut meal that was assigned an arbitrary potency of 100,000 U/ml. In confectionery products spiked with varying quantities of peanut (0.7% to 0.0175%), the recovery of peanut allergen ranged from 31% to 94%. The sensitivity of the assay was 2.5 U/mg of dry weight from these samples (0.00875% peanut). Peanut allergens were undetectable in virgin vegetable oil used to roast peanuts, but 600 to 7600 U/mg of dry weight were present in oil after varying periods of use. The allergen content of used oil was reduced to 8 U/mg of dry weight by filtration and steam cleaning. The availability of such assays provides a means of monitoring finished food products for potential allergens. This monitoring in turn will provide the means to correlate symptoms experienced by sensitive patients with the exact quantity of allergen ingested. At the present time, there is little information on the quantities of ingested peanut allergen that pose risks to peanut-sensitive subjects.

Detection and quantitation of raw fish aeroallergens from an open-air fish market

BACKGROUNDnIgE-mediated hypersensitivity to fish is a clinically relevant problem, particularly in several European countries. Although most allergic reactions to fish are caused by ingestion, occupational exposures to seafood allergens by inhalation have been correlated with respiratory symptoms. In Madrid, patients with fish allergy have exhibited respiratory symptoms after visits to an open-air fish market.nnnOBJECTIVEnWe sought to study the possibility of passively aerosolized fish allergen in an open-air fish market through air sampling and a competitive IgE immunoassay.nnnMETHODSnAir samples were collected on polytetrafluoroethylene filters by using air samplers. Samples were collected on 41 different days from both an open-air fish market and an outdoor residential area. Fish allergens were specifically quantified by competitive IgE immunoassay by using pooled sera from fish-sensitive individuals. A raw fish extract (10 mg of dry weight/mL) was used as the reference standard.nnnRESULTSnAllergen was quantified in all 39 fish market air samples (2-25 ng/m(3)). The residential air samples contained no detectable allergen. The analytic limit of detection was 2 ng, allowing detection of 0.4 ng/m(3) for the air volumes collected. A concentrated (30-fold) pool of fish market air samples was tested in serial dilutions and demonstrated an identical regression line to that of the raw fish standard.nnnCONCLUSIONnBy using air sampling and an immunochemical analytic technique, fish allergen is detectable in the air of an open-air fish market. Avoidance of a food allergen, such as fish, should include preventing exposure to aerosolized particles through inhalation in relevant environments.