Seasonal variation of airway function in allergic rhinitis

J. ALLERGY CLIN. IMMUNOL. MAY 1986

Rauls et al. With this analytical procedure, 20 to 25 samples plus standards and controls are routinely run in triplicate in a day. Therefore, this procedure is particularly useful for demonstration of elevated histamine from various challenges, since all samples can be included within a single analytical run. The enzymatic isotopic assay is very sensitive to alterations in the analytical matrix and to inhibition by a variety of drugs. Careful evaluation of appropriate controls is required before analysis of histamine in other biologic fluids or in the presence of drugs. We gratefully acknowledge the technical assistanceof Robert W. Haverly, Peggy Casteel, and Alice Armendariz. REFERENCES 1. Shore PA: The chemical Biochem Anal Suppl:89,

determination 1971

of histamine.

Seasonal variation allergic rhinitis

Methods

2. Beaven MA, Horakova 2: The enzymatic isotopic assay of histamine. Handbook Exp Pharmacol 18(2): 15 1, I977 3. Verburg KM, Bowsher RR, Henry DP: A new radiocnzymatic assay for histamine using purified histamine N-methyltransferase. Life Sci 32:2855, 1983 4. Brown MJ, Ind PW, Causon R, Lee TH: A novel double-isotope technique for the enzymatic assay of plasma histamine: application to estimation of mast cell activation assessed by antigen challenge in asthmatics. J ALLERGY CLIN IMMUNOL 69:20, 1982 5. Dyer J, Warren K, Merlin S, Metcalf DD, Kaliner M: Measurement of plasma histamine: description of an improved method and normal values. J ALLERGY CLIN IMMUNOL 70:82, 1982

6. Shaff RE, Beaven MA: Increased sensitivity of the enzymatic isotopic assay of histamine in plasma and serum. Anal Biochem 941425, 1979 7. Verburg KM, Bowsher RR, Henry DP: Kinetic analysis of the histamine N-methyltransferase reaction as used in the histamine radioenzymatic assay: optimization of assay specificity. Life Sci 3.5:241. 1984

of airway

Adi A. Gerblich, M.D., Howard J. Schwartz, Edward H. Chester, M.D. Cleveland, Ohio

function

in

M.D., and

We set out to examine seasonal variation in airway bronchoconstriction in patients with seasonal allergic rhinitis. Airway conductance and response to methacholine challenge were measured during pollen season, as well as in winter when pollen exposure was not present. Airway conductance and spirometry were performed on 17 subjects during allergy season and in winter. In eight of these subjects the measurements were repeated in the successive allergy season. Methacholine bronchoprovocation was pegormed on I7 of the subjects in winter and in eight subjects in allergy season. We found airway constriction in both allergy seasons as evidenced by speciJic airway conductance (SC,,) of 0.188 2 0.06 and 0.203 * 0.03. In contrast, SC,, during winter was 0.27 ? 0.11. When winter and summer seasons were compared, both summer SC., values were significantly lower than winter SC.,, p < 0.01 and p < 0.05, respectively. Mean airway sensitivity to methacholine during allergy season was 16.1 breath units and not different than out of season 11.7 breath units; p = NS. The reactivity to methacholine (slope of the dose-response curve) and spirometry (FVC, FEV,, FEV,IFVC) in and out of allergy season were likewise not different. The data indicate that patients with allergic rhinitis have unique physiologic behavior separating them from patients with asthma or normal subjects. They develop seasonal bronchoconstriction unassociated with clinical bronchospasm, but this seasonal bronchoconstriction does not potentiate their sensitivity to me&choline. However, they have increased airway sensitivity to methacholine, and this feature distinguishes them from normal subjects. (J ALLERGY CLIN IMMUNOL 77:676-81, 1986.)

From the Pulmonary Division, Department of Medicine, Veterans Administration Medical Center, and Case Western Reserve University, Cleveland, Ohio. Supported by Veterans Administration Medical Research Service. A. Gerblich, M.D., was supported by an E. L. Trudeau fellowship.

Received for publication Jan. 30, 1984. Accepted for publication Oct. 16, 1985. Reprint requests: Adi A. Gerblich, M.D., Research Building K207, 10701 East 44106.

VA. Blvd.,

Medical Center, Cleveland, OH

VOLUME 77 NUMBER 5

Allergic rhinitis is a common disease that has been considered to affect only the upper respiratory tract, including the sinuses. Aeroallergens impacting on the nasal mucosa of allergic persons elicit an immediatetype hypersensitivity reaction characterized by local swelling and mucous hypersecretion.‘” Recently, several studies in patients with symptomatic allergic rhinitis described abnormalities in pulmonary airway mechanics, the presence of which was compatible with lower respiratory tract dysfunction.4-6 Indeed there was persistence of these abnormalities out of the allergy season.‘. ’ It thus appeared that symptomatic allergic rhinitis can be accompanied by concurrent abnormalities in pulmonary functions that do not reverse after pollen exposure ceases. This persistence raised the possibility that these functional abnormalities are independent of exposure to specific seasonal allergens. The studies we report further examine the influence of allergy season on pulmonary function and attempt to validate the perennial nature of pulmonary function abnormalities in seasonal allergic rhinitis. We demonstrate that sensitive tests of airway function do return to normal when patients are studied out of allergy season. Furthermore, this return to normal occurs in spite of these same patients demonstrating perennial hyperreactivity to methacholine. METHODS Seventeen subjects with uncomplicated seasonal allergic rhinitis were tested in winter and summer. In eight of these subjects, the measurements were repeated in the successive summer. Then: were nine female and eight male subjects with a mean age of 25.8 years (range 17 to 45 years). They were all symptomatic in late summer months and complained at the study time of sneezing, nasal stuffiness, rhinorrhea, and/or postnasal drip. None of these complaints were noted during the winter months. None had a past history of smoking, wheezing, or cough, and none had any history of seasonal atopic asthma. A control group of eight normal nonsmoking subjects without allergies or respiratory complaints had the same testing as the allergic group during the winter season. Their mean age was 28 years (range 21 to 39 years). The period of clinical nasal symptoms will be referred to as “season.” Examination for the presence of functional thoracic airway abnormalities included forced expiratory flow rates as determined on a 13.5 L spirometer (Warren E. Collins, Braintree, Mass.) and airway resistance and thoracic gas volume as measured with a constant volume plethysmograph accordingto the method of DuBois et al.‘- * The reciprocal of airway resistance, the conductance, was divided by the volume of thoracic gas and reported as specific conductance, SC,, (s-l cmH,O-‘). Subjects were instructed to stop any medications for 1 week before testing and to avoid any caffeine containing beverages at the moming of testing. After baseline spirometry and plethysmography, bronchial provocation was conducted according to

Seasonal

variation

of airway

function

in allergic

rhinitis

Abbreviations used SG,,: Specific airway conductance BU: Breath unit PD,,: Methacholine provocation dose required reduce SG,, 35% below baseline NS: Not significant

677

to

the National Institute of Allergy protocol.” Methacholine solutions, freshly prepared for each study, were diluted in saline at an initial concentration of 0.075 mg/ml and administered at twofold increments from the initial concentration. Progressive methacholine challenge was continued until at least a 35% decline in SG,, was achieved or a concentration of 25 mg/ml was attained. Subjects not responding to a concentration of 25 mg/ml of methacholine were defined as nonresponders, and no further bronchoprovocation was performed.’ The inhalations were carried out with a DeVilbiss model No. 42 nebulizer (DeVilbiss Co., Somerset, Pa.) driven by compressed air at 6 L/min, activated at the end of tidal expiration, and stopped at the end of maximal inspiration. After five maximal inspiratory maneuvers with methacholine, the subject resumed tidal breathing with room air for 2 to 3 minutes, after which the volume of thoracic gas, SG,,, and forced expiratory flow rates were determined, in that order. The interval between methacholine doses did not exceed 10 minutes. The PD,, was computed by plotting and connecting two adjacent SG,, measurements on both sides of the 35% line and extrapolating the cumulative dose of breath units.” Dose-response curves were constructed by plotting a logarithmic transformation of the cumulative breath units against the measured SG,,. Slopes were calculated following linearization of the data. PD,, and the slope of the dose-response curve were used as a measure of airway sensitivity and reactivity, respectively, as described by Orehek et al.‘” Two puffs of 125 pg isoproterenol were used to reverse any induced bronchial constriction. Data were analyzed by a paired t test or a Kolmogorov-Smimov test.

RESULTS Seasonal variation in baseline bronchomotor tone The subjects were tested in two successive allergy seasons (groups A and C in Table I) and had a mean k SD SG,, of 0.188 k 0.06 and 0.203 t 0.03. These same patients had a mean out of season SG,, of 0.270 t O.‘ll (group B, Table I). These wintertime values were not significantly different than their predicted SG,,,“’ ‘* whereas both seasonal measurements were significantly lower (p < 0.01 and p < 0.05). These results indicate that our patients with simple allergic rhinitis had bronchoconstriction during the two successive allergy seasons, whereas their bronchomotor tone was normal during the winter

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TABLE 1. Baseline

J. ALLERGY CLIN. IMMUNOL. MAY 1966

pulmonary

function

tests in subjects

with allergic

rhinitis

during

three

seasons

Groups A

Season N FEV, FVC FEVJFVC SGaw

Summer 17 3.54 k 4.34 t 80.0 2 0.188 -t

times 100

B

Winter 17 3.54 4.24 84.1 0.270

0.74 0.84 6.9 0.06*

measurements were done before any testing. Same subjects *P < 0.05 when compared to winter ki,. All

function tests after bronchoprovocation Allergic Group

Season Number of subjects FEV, FVC FEVJFVC times 100

rhinitis

A

Winter 17 3.44 + 0.77 4.22 + 1.0 82.4 -+ 6.9

Measurements were done after the last methacholine each bronchoprovocation.

Group

C

Summer 8 3.68 + 0.86 4.28 + 1.1 82.1 + 5.9 inhalation

for

season. No difference was noted in the degree of bronchoconstriction between the two allergy seasons, group A versus C (p = NS). In addition, during both allergy seasons, SG,, for subjects with allergic rhinitis (groups A and C) was significantly different from the mean SG, of 0.249 t 0.05 of the control normal group (p < 0.05). This was not the case out of season, when the baseline SG,, of both subjects with rhinitis and normal subjects were statistically similar. In contrast to the seasonal changes, we found, in the SG,, measurements of patients with allergic rhinitis, no significant differences in FVC, FEV,, and FEV,/FVC were observed during the same periods (Table I). To look for a possible relationship between the out of season and in season bronchomotor tone, we plotted the SG,, measurements of both seasons (Fig. 1) and found that patients with high out of season SG,, had larger in season falls in SG,, (distance from line of identity) than those patients with low out of season SG,,. Bronchoprovocation out of season

with

Summer 8 3.68 + 4.31 r 85.5 k 0.203 +

0.75 1.0 6.4 0.11

0.87 1.0 6.3 0.03*

were tested in the three seasons.

TABLE II. Pulmonary methacholine

+A k t

C

methacholine

We conducted methacholine bronchoprovocation tests during the winter on ,17 subjects with rhinitis. Fifteen of the 17 subjects responded with a significant

reduction of baseline SG,,. The PD35 was highly variable with a mean of 11.7 BU and a range of 0.2 to 32.5 BU of methacholine. We found the response to methacholine to depend on the baseline level of bronchomotor tone as measured by SG,,. To demonstrate this pattern, subjects were divided into subjects with a high bronchomotor tone and subjects with a low bronchomotor tone, defined by an SG, above or below 0.25. Eight subjects had SG,, above 0.25, and nine subjects had SG,, below 0.25. After the first methacholine dose (0.375 BU) the two groups reacted differently (Fig. 2). The group with the lower baseline bronchomotor tone (SG,, > 0.250) constricted significantly more (p < 0.01) than the group with a high baseline bronchomotor tone (SG,, < 0.25) p = NS. After the second dose (1.125 BU), the same pattern holds; however, by this time all subjects had an SG,, < 0.25. The spirometq measurements of FVC, FEV,, and FEVJFVC after the methacholine bronchoprovocation did not demonstrate any significant change, even at the last provocation dose (Table II). The nonallergic control group that demonstrated a baseline SG,, of 0.242 + 0.05 had bronchoprovocation testing, and their response to methacholine was compared to the allergic rhinitis group. Of the eight subjects, five who were challenged were negative, not responding to a concentration of 25 mg/ml. Of the three responders, the PD,, was 15, 18, and 82, respectively. The response of the patients with allergic rhinitis was significantly earlier (to a lower challenge dose), as measured by a KolmogorovSmimov test, p < 0.05. Bronchoprovocation season

with

methacholine

in

Eight of the original 17 subjects with rhinitis were restudied in the next allergy season and were found to have a mean baseline SG,, of 0.203 + 0.03. These same subjects out of season had a mean SG,, of 0.250

+ 0.07; p < 0.05.

This comparison

reaffirms

VOLUME 77 NUMBER 5

Seasonal

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679

r-------- 1 p > .I

3ASELINE

IsT DOSE METHACHOLI

SPECIFIC

COhDUCTANCE

OUT OF SEASON (SGaw

see-‘cm

H,O-’

)

FIG. 1. SG, out of season (winter) is depicted against the SG., in two successive summer seasons. First summer (0); second slummer (0). Higher out of season SG., was associated with larger deviation from the identity line.

the bronchoconstrictive effect of the natural seasonal pollen challenge on these subjects. By performing a methacholine bronchoprovocation challenge during allergy season, we examined whether or not the response to methacholine had been affected during the allergy season. The PD,, of methacholine during the allergic season was 16.1 BU (with a range of 4.2 to 40). This was not significantly different from the out of season value of 11.7 BU (p ,= NS). The seasonal effect on the methacholine reactivity is depicted in Fig. 3. The mean reactivity of group C in season was 0.05 +- 0.01, whereas the mean out of season reactivity for the same subjects was, 0.25 + 0.42; p = NS. The seasonal effect on the reactivity to methacholine was depicted by computing a regression line and a 95% confidence band for the slope (Fig. 3). I3

DISCUSSKIN We have demonstrated the presence of seasonal airway constriction in patients with seasonal allergic rhinitis. This bronchoconstriction is reversible, disappearing spontaneously after the conclusion of allergy season. We also demonstrated the persistence of hyperreactivity to methacholine throughout the year in these patients. The airway constriction induced in allergic rhinitis, whether by allergen or by methacholine, appeared to relate to the bronchomotor tone of the unprovoked airways. However, with an already constricted airway that we found in allergy season, the characteristics of the response to methacholine did

NE

FIG. 2. Airway response to 0.375 BU of methacholine inhalation in group B (out of season). Eight subjects with a baseline SG,, greater than 0.25 (0) and nine subjects with an SG., smaller than 0.25 (0) demonstrating different SG., response to the same bronchoprovocation.

not change. From these data we argue that the airways of subjects with allergic rhinitis behave more like airways of normal subjects than that of subjects with asthma. I4 Several studies have demonstrated functional airway abnormalities in seasonal allergic rhinitis but failed to demonstrate the reversibility of these findings out of allergy season. In the study by Fairshter et al.,6 subjects with allergic rhinitis demonstrated airway constriction both “in” and “out” of allergy season. However, this study was conducted in southem California, and subjects were almost certainly exposed continuously to pollen, since residing involves exposure to various trees, grasses, and weeds that may pollinate almost all year long. Such prolonged pollination may obviate the seasonal difference in airway function, demonstrated in our study, that was conducted in northeastern Ohio. In the Ohio area significant weather variation between summer and winter is the norm, and there is a pollination profile without detectable pollen counts during a long winter season. 15.” Therefore, our out of season airway conductance would not be affected by continual plant pollination and represents a reliable measure of airway bronchomotor tone unprovoked by pollen exposure. These factors may account for our ability to measure variation in some airway function between seasons. In contrast to the observed variation of SG,, values, we were unable to find any abnormalities in spirometric variables ( FVC, FEV , , and FEV ,/FVC) during allergy season. Spirometric responses to methacholine in our patients with allergic rhinitis also demonstrated

660

Gerblich

-

et al.

J. ALLERGY CLIN. IMMUNOL. MAY 1986

I

\ Tl

’

.I 13.324 LOG

OF

1

I

0.571

.84

CUMULATIVE

I

1.12

1

1.41

BREATH

I

1.7 UNITS

FIG. 3. Airway response to methacholine inhalation in eight subjects measured during allergy season (group C) (0) and out of allergy season for the same subjects (0). A logarithmic transformation of the cumulative breath units and the corresponding SG,s were computed by a regression line with the 95% confidence interval about any point on the line.

no seasonal variation. Rosenthal et al.’ also reported perennial abnormalities in airway function in their study. However, they did not report any baseline measurements out of season. The physiologic basis for these observed abnormalities in airway function is unclear. One possible explanation for this pattern in subjects with allergic rhinitis is a lack of sensitivity of small airways to bronchoconstrictive signals. Fish et al.” have suggested this behavior as another distinguishing feature between subjects with rhinitis and subjects with asthma. Another possible explanation for lack of seasonal variation in bronchomotor tone may be observed in Fig. 1. If the sampled group has a mean SG,, 0.200 and a small interindividual variance, the likelihood of finding a bronchoconstrictive effect during the allergic season is low. This is due to the propensity of subjects with higher bronchomotor tone (lower SG,,) to constrict less to a challenge than patients with low initial bronchomotor tone (higher SG,,). A subject sample with large interindividual variance in baseline bronchomotor tone as in our group is more likely to display seasonal variations in airway behavior. Such difficulties may explain the perennial abnormalities observed by Rosenthal et a1.5 and that were taken to indicate a lack of seasonal variations of bronchomotor tone in allergic rhinitis.6 The correlation depicted in Fig. 1 is of interest because it indicates an inverse relationship

between airway caliber and the extent of the bronchoconstriction. Studies of normal subjects in whom bronchoconstriction was induced by vagal stimulation demonstrated a similar correlation between baseline bronchomotor tone and the bronchoconstrictor response to vagal stimulation.‘8-20 Conversely, it is difficult in subjects with asthma to demonstrate this relationship.“. *‘, ** Contrary to several studies in subjects with asthma, we did not observe any changes in airway reactivity to methacholine challenge during allergy season. I4 The bronchoconstriction by methacholine during summer was not significantly different than the response to methacholine challenge during winter. This was the case for PD35as well as the slopes of the group dose-response curves (Fig. 3) and indicates a lack of potentiation of the several bronchoconstrictive stimuli during allergy season. In contradistinction to the additive effect in allergic rhinitis that we observed, the combined effect of two bronchoconstrictive signals of different nature in asthma demonstrates potentiation of bronchial obstruction. 14.23.24 Thus, the only functional abnormality we can demonstrate out of season in patients with allergic rhinitis is large airway hyperreactivity to methacholine (SG,,), as compared to normal subjects. In contrast to subjects with asthma, this hyperreactivity did not worsen in allergy season, although bronchoconstriction was evident. Thus, patients with allergic rhinitis are intermediate in the quality of their airway hyperresponsiveness between normal subjects and subjects with asthma. Whether such findings represent a stage in the eventual development of asthma or whether subjects with rhinitis remain a separate, distinct group in these regards is a subject of long-term study. REFERENCES 1. Kaliner MA, Wasserman SI, Austen KF: Immunologic release of mediators from human nasal polyps. N Engl J Med 289:277, 1973 2. Mygind N: Mediators of nasal allergy. J ALLERGYCLIN IM-

MUNOL70:149, 1982 3. Kawabori S, Okuda M, Unno T: Mast cells in allergic nasal epithelium and lamina propria before and after provocation: an electron microscopic study. Clin Allergy 13: 181, 1983 4. Morgan EJ, Hall DR: Abnormalities of lung function in hay fever. Thorax 31:80, 1976 5. Rosenthal RR, Bleecker ER, Laube B, Norman PS, Permutt S: Effect of environmental antigen on cholinergic hyperreactivity. Chest 75(suppl 2):228, 1979 6. Fairshter RD, Novey HS, Marchioli LE, Wilson AF: Large airway constriction in allergic rhinitis: response to inhalation of helium-oxygen. J ALLERGYCLIN IMMUNOL63:39, 1979 DeBois AB, Botelho SY, Comroe JH Jr: A new method for measuring airway resistance in man using a body plethysmograph: values in normal subjects and in patients with respiratory disease. J Clin Invest 35:327, 1956 DuBois AB, Botelho SY, Bedell GN, Marshall R, Comroe JH:

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A rapid plcthysmographic method for measuring thoracic gas volume. J Clin Invest 35:322, 1956 9. Chai H, Fan RS, Forehlich LA, Mathison DA, McLean IA, Rosenthal RR, Sheffer AL, Spector SL, Townley RG: Standardization of bronchial inhalation challenge procedures. J ALLERGY CLIN

IMMUNOL

56:323,

17.

1975

10. Orebek J, Gayrard P, Smith AP, Grimaud C, Cbarpin J: Airway response to carbachol in normal and asthmatic subjects. Am Rev Respir Dis 115:937, 1977 11. Briscoe W4, DuBois AB: The relationship between airway resistance, airway conductance, and lung volume in subjects of different age and body size, J Clin Invest 37:1279, 1958 12. Doershuk CF, Fisher BJ, Matthews LW: Specific airway resistance from the perinatal period into adulthood. Am Rev Respir Dis 109:452, 1974 13. Sokal RR, Rohlf FJ: Biometry. San Francisco, 1969, WH Freeman, pp 526-32 14. Cockcroft DW, Ruffin RE, Dolovicb J, Hargreave FE: Allergen-inducead increase in nonallergic bronchial reactivity. Clin Allergy 7:5~03, 1977 15. Samter M: Regional allergy of United States, Canada, Mexico, and Cuba. Durham, N. C., 1955, Charles C Thomas, pp 65-80 16. Solomon ER, Durhan OC, McKay FL: Aeroallergens. II. Pollen and the plants that produce them. In Sheldon JM, Love11

18. 19.

20.

variation

of airway

function

in allergic

rhinitis

RG, Mathews KP, editors: A manual of clinical allergy. Philadelphia, 1967, WB Saunders Co, pp 340-436 Fish JE, Rosenthal RR, Summer WR, Bata G, Menkes H, Summer W, Permutt S, Norman P: Airway responses to methacholine in allergic and nonallergic subjects. Am Rev Respir Dis I13:579, 1976 Lloyd TC: Bronchoconstriction in man following single deep inspiration. J Appl Physiol l&114, 1963 Nadel JA, Salem H, Tamplin B, Tokiwa Y: Mechanism of bronchoconstriction during inhalation of sulfur dioxide. J Appl Physiol 20: 164, 1965 Kaufman J, Wright GW: The effect of nasal and nasopharyngeal irritation airway resistance in man. Am Rev Respir Dis 100:626,

1969

21.

Cade JF, Pain MCF: Role of bronchial reactivity in aetiology of asthma. Lancet 38:186, 1971 22. Rubinfeld AR, Pain MCF: Relationship between bronchial reactivity, airway caliber, and severity of asthma. Am Rev Respir Dis 11.5:381, 1977 23. Orehek J, Massari JP, Gayrard P, Grimaud C, Charpin J: Effect of short-term low-level nitrogen dioxide exposure on bronchial sensitivity of asthmatic patients. J Clin Invest 57:301, 1976 24. Schofield NM, Green M, Davies RJ: Response of the lung airway to exercise testing in asthma and rhinitis. Br J Dis Chest 74:155, 1980

A qualitative and quantitative analysis of proteins found in vespid venoms Ilorraine M. Mulfinger, B.S., Allen W. Benton, Ph.D., Miles W. Guralnick, M.S., and I?ichard A. Wilson, Ph.D.* Spring Mills and University Park, Pa. LIiagnosis and immunotherapy with venom extracts of patients sensitive to Hymenoptera stings has led to the problem of improving the standardization of Hymenoptera venom products. Current methods of standardization use the Lowry protein determination and a radial-difSusion assay for hyaluronidase activity. This study demonstrates that the results of these analyses do not always correlate with the actual quantity of allergenic protein present in the extracts. A method of standardization is examined herein that uses polyacrylamide gel electrophoresis to quantitate phospholipase A, antigen 5, and hyaluronidase, the proteins that together comprise most allergenic protein present in the venoms.’ Also discussed in this study is the biochemical variability of phospholipase A and antigen 5 in the venoms of the difSerent vespid species examined. (JALLERGYCLINIMMUNOL77&U-6, 1986.)

Diagnosis and treatment of insect sting allergy is becoming more and more effective with the gradual From Vespa Laboratories, Spring Mills, Pa. Received for publication July 17, 1984. Accepted for publication Oct. 16, 1985. Reprint requests: Lorraine M. Mulfinger, B.S., Vespa Laboratories, R. D. No. 1, Spring Mills, PA 16875. *Department of Veterinary Science, Pennsylvania State University, University Park, PA 16802.

change from the use of vespid and Apis WBEs to venom extracts. Work by Sobotka et a1.2demonstrated a definite correlation between allergic individuals and positive skin tests when venom extracts were used. This same type of study had previously failed to demonstrate any correlation when WBEs were used.3.4 A subsequent controlled study of immunotherapy comparing WBE, venom, and placebo demonstrated venom to be clinically superior to WBE in providing 681