Abe Resnick

Skin and serologic testing in the diagnosis of latex allergy

BACKGROUND Latex hypersensitivity is associated with occupational allergy, contact urticaria, rhinitis, asthma, and anaphylaxis. However, standardized sensitive and specific latex extract for skin prick or serologic testing is not available in the United States. METHODS We investigated the reliability of two latex extracts in 118 consecutive skin tests in patients with spina bifida, health care workers, and other patients with symptoms of latex allergy, and 10 control subjects. RESULTS Forty-two of 86 patients with spina bifida, 11 of 15 health care workers with symptoms of latex allergy, 6 of 7 patients with symptoms of latex allergy, and 0 of 10 control subjects had demonstrable immediate wheal and flare responses to latex prick testing. In addition, 95 patients and 10 control subjects were tested concurrently for latex-specific IgE by ELISA. Of 55 patients with positive skin prick test results, 48 were reactive as determined by ELISA for IgE-specific latex antibody (sensitivity = 87%). Latex ELISA titers were significantly higher in patients with positive skin prick test results with a history of anaphylaxis to latex and in individuals without symptoms of latex allergy who had positive skin prick test results when compared with patients with negative skin prick test results. During the skin test procedure, nine patients had adverse reactions, including anaphylactic reactions in four. CONCLUSIONS Skin prick and serum testing are reliable methods of diagnosing latex allergy. Serologic evaluation may be more desirable until allergen standardization is available.

Comparison of latex hypersensitivity among patients with neurologic defects

BACKGROUND Latex hypersensitivity has been described in discrete populations including health care workers and children with spina bifida (SB). OBJECTIVE This study was designed to determine whether the SB population is a unique neuroimmunologic group manifesting this sensitivity. METHODS Four groups of subjects were studied. These included: 36 patients with SB with or without clinical evidence of latex hypersensitivity, 50 patients with spinal cord injury (SCI), and 10 patients with cerebrovascular accidents (CVAs), all of whom were questioned regarding contact with and possible clinical allergic reactions to latex. Ten healthy control subjects were also studied. We used a latex sap extract, previously shown to react with latex-specific IgE in a biotin-avidin ELISA, to determine latex-specific IgE antibody titers and to compare the groups. RESULTS Responses to questionnaires indicated that neither the patients with SCI nor the patients with CVA had histories suggestive of latex hypersensitivity. In contrast, 72% of the SB population had histories of clinical latex allergy. Comparisons of latex contact among the SB, SCI, CVA, and control groups revealed that the SB and SCI groups had similar latex exposure, whereas the other groups had less exposure. Both the SB and SCI groups had an average of two surgical procedures per year, which was greater than the average for the other groups. Comparisons of IgE latex antibody titers among the groups indicated that only the SB group had significant levels. The mean optical density values for each group were: 0.299 +/- 0.177 for patients with SB and positive skin prick test results, 0.072 +/- 0.066 for patients with SB and negative skin prick test results, 0.098 +/- 0.005 in patients with SCI, 0.073 +/- 0.038 in patients with CVA, and 0.053 +/- 0.034 in control subjects. The percentages of positive latex IgE antibody detection were 72% for SB, 4% for SCI, 0% for CVA, and 0% for control groups. CONCLUSIONS The results suggest that the SB population is unique in demonstrating IgE responses to latex contact, which may be due to increased latex exposure or altered neuroimmunologic interactions.

Aspergillus fumigatus peptides differentially express Th1 and Th2 cytokines

Relevant allergens from Aspergillus fumigatus associated with allergic bronchopulmonary aspergillosis (ABPA) have been cloned and expressed. The pathogenesis of ABPA probably depends on specific cytokines and immunoglobulins secreted by lymphocytes on stimulation with different epitopes of those allergens. In the present study, we synthesized peptides of 12-16 amino acids from the sequence of Asp fI and compared their immunological responses in four mice strains (BALB/c, C57BL/6, AKR, and CBA). Of the five peptides studied for their cytokine profile, one showed a clear Th1, whereas another showed a Th2 response. The remaining three peptides varied in their immunoreactivity. The results suggest that a number of epitopes of diverse activities are present in individual molecules and may be involved in the pathogenesis of ABPA through differential cytokine secretions.

Enzyme profile and immunochemical characterization of Aspergillus fumigatus antigens

We have compared the immunochemical characteristics of culture-filtrate antigens (Ag) from Aspergillus fumigatus extracted in our laboratory with commercially available Ags. A total of 20 different preparations were studied for protein and carbohydrate content, presence of endotoxins, mycotoxins, and hemolytic toxins. These extracts were analyzed by two-dimensional electrophoresis for protein components. The immunogenicity of the preparations was determined by rocket electrophoresis with rabbit anti-A. fumigatus sera and by agar gel diffusion with sera from patients with allergic bronchopulmonary aspergillosis, aspergilloma, and normal control subjects. In order to have dependable immunologic results, the Ags must be sufficiently pure and reproducible. Until such time as pure and standardized Ags are available, the crude Ags used should be characterized to the extent that adequate reproducibility between preparations can be ascertained. The enzyme profile of the Ag preparations provides a fair indication of the quality of antigenic components, and together with other immunochemical parameters, it will be of use in determining the suitability of the extracts in immunodiagnosis. Immunochemical results demonstrate that commercial Ags contain less proteins and carbohydrates and fewer enzymes than the homemade antigens. In addition, fewer patients demonstrated specific precipitins against commercial Ags than with homemade Ags. This study once again confirms the need for pure standardized Ags for studying the immunologic response in patients with Aspergillus-induced diseases. Until such preparations are readily available, partially purified or crude Ags with known immunochemical properties and enzyme profile may be the choice for immunodiagnosis.

Characterization of latex antigen and demonstration of latex-specific antibodies by enzyme-linked immunosorbent assay in patients with latex hypersensitivity

Two latex antigens, one extracted from surgical gloves (GE) and the other from the sap of Hevea brasiliensis plant (RPE) were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and two-dimensional gel electrophoresis. These antigens were used to detect latex specific IgE and IgG antibodies by enzyme-linked immunosorbent assay (ELISA) in the sera of patients with meningomyelocele (spina bifida) and of normal controls. Of the 36 patients studied, 26 had wheal-and-flare skin-prick test reactivity to latex antigen with 11/26 having had a history of anaphylaxis to latex products. Twenty three of the 26 sera from skin-test positive patients and 10/11 patients with history of anaphylaxis demonstrated significant levels of latex specific IgE and IgG in the sera, whereas only 1/14 normals showed significant antibodies to latex. The remaining 10 patients, all skin-test negative with latex antigens, showed only low levels of antibodies. The findings indicate that the ELISA used in the present study employing partially characterized antigens has sensitivity and specificity to detect latex specific antibodies in the sera of suspected patients and can be used for presumptive diagnosis of latex allergy.

Immunopathological response of C57BL/6 and C3H/HeN mice to Aspergillus fumigatus antigens

C3H/HeN and C57BL/6 mice were exposed to culture filtrate (CF) and mycelial extracts (ME) of Aspergillus fumigatus (Af) intranasally. Animals received 6, 8 or 10 biweekly doses and were sacrificed 2 weeks after the last dose was administered. Specific antibodies against Af were detected in their sera by biotin-avidin-linked immunosorbent assay (BALISA). Antibodies against Af belonging to all isotypes showed an increase in both strains of mice. A progressive increase in IgG and IgA antibody isotypes against both CF and ME antigens was detected in C3H/HeN mice during the entire experimental period, whereas most antibody levels peaked after the 8th dose and remained steady or decreased slightly in the C57BL/6 strain. Lung lavage studies showed a relative decrease in the number of macrophages and an increase in the number of lymphocytes after the 6th and 8th instillation of Af antigens in both strains of mice. Histology of the lung demonstrated a progressive inflammatory reaction in C57BL/6 mice during the experimental period. On the other hand, the C3H/HeN mice showed a negligible inflammatory pulmonary reaction. The antibody responses and inflammatory changes detected in the lungs of mice exposed to Af antigens are comparable to allergic bronchopulmonary aspergillosis (ABPA) in humans and hence this model will be of value in understanding the disease mechanism in ABPA and related diseases.

Comparison of Antigens and Serological Methods in Aspergillus fumigatus Antibody Detection

Summary: Using antigens from three strains of Aspergillus fumigatus (AF), 97 sera were studied for specific antibodies by agar gel double diffusion (DD), indirect immunofluorescence (IIF) and enzyme‐linked immunosorbent assay (ELISA). The results showed wide variation in the reactivity of the different antigens and different methods. It is also evident from the results that several different AF antigens and serological methods are useful in demonstrating antibodies in the sera and in avoiding false positive and negative results. However, it is not possible to make a diagnosis solely from the serological results, as a majority of the sera from non‐AF‐induced lung diseases showed comparable reactions to those of aspergilloma and allergic bronchopulmonary aspergillosis (ABPA). This study confirms the necessity of standardized antigens for reliable and dependable results irrespective of the methods employed.

Immunologic response to Faenia rectivirgula (Micropolyspora faeni) in a dairy farm family

In the present study, cellular and humoral responses to Faenia rectivirgula antigens were evaluated in seven subjects, members of a family who lived and worked on a dairy farm. Four subjects had clinical features of hypersensitivity pneumonitis after exposure to moldy hay. The other three subjects had no clinical disease in spite of similar exposure. Although serum precipitins were found in most subjects, a biotin-avidin-linked immunosorbent assay revealed high levels of F. rectivirgula-specific antibodies only in the symptomatic subjects. In addition, numerous precipitin arcs were present in the sera of the symptomatic but not the asymptomatic subjects by antigen-antibody crossed immunoelectrophoresis. No clear distinction between symptomatic and asymptomatic subjects could be made on the basis of lymphocyte phenotype studies, and antigen-induced lymphocyte transformation was not detected in any subjects. The results indicate that F. rectivirgula-specific antibody levels as detected by biotin-avidin-linked immunosorbent assay and by the presence of precipitin arcs in crossed immunoelectrophoresis may differentiate symptomatic and asymptomatic farmers.

Medium for susceptibility testing and yeast phase conversion of Blastomyces dermatitidis

Cottonseed protein agar and a modified Tween-albumin casein hydrolysate (TAC) medium were compared for the yeast phase conversion of Blastomyces dermatitidis strains including fresh isolates as well as strains maintained in long-term storage. It was found that both media converted all the B. dermatitidis (mycelial phase) strains studied to yeast phase in three days. The TAC medium has the added advantage that it is clear and the growth can be recognized earlier than in the opaque cottonseed agar medium. The conversion in most cases was more than 95% and the morphology of the yeast cells was uniformly typical with broad base budding. There was a striking difference between the sensitivity of the yeast and mycelial phases of B. dermatitidis strains. The yeast phase was usually more sensitive to Amphotericin B than the mycelial phase of B. dermatitidis. Similarly, the yeast phases of four out of six strains were more sensitive to ketoconazole than their respective mycelial phases, while two strains showed identical sensitivity in cottonseed agar. The yeast phase organism was more susceptible to Amphotericin B when cottonseed medium was used whereas the yeast phase showed more susceptibility to ketoconazole in TAC medium. Since the sensitivity among the various strains differed, it is necessary to determine the antifungal susceptibility of the pathogenic phase of the organism for initiating proper therapy and monitoring effectiveness.