48 Comparison of methacholine bronchial reactivity and IgE levels in twins

45 AlWY IN TWINS S.Banini, G.&asi, 1 Clinica Medica,

M.E.Trillb, University

A.Franci of Rune,

47

IZEJ.ATIONsHTp OF THE lA#dUNE RFSWNSE ‘IQ PURIFIEU RAGWEEDAFMGENS AND THE IL&DR SYm. M Blmnthal, B Raittnan-Johnson, G Gleich, K El&on, L coodfriend, G Walsh, K J&rzxxi, E Yunis. Minneapolis, MN, Rochester, mhlN!Rlontreal, ore, Boston, MA. The relationship of the inmune reqxmse tc> purified ragweed antigens and the l&4 system was investigated in 148 ragweed sensitive and 100 non-atopic individuals. All subjects received a history and physical exam, prick and tjtratim intradeskin testing and blood was drawn for HU A,B,C and Dr typing, and SXLKR IgE and RAST levels. The imrune response to crude ragweed, antigen E, Ra3, and Ra5 was evaluated by Rash and skin testing. Serum IgE levels were determined by radio-e assay. &XX wert: performed using the microcrystalline cellulose method of Gleich. HLA A,B, and C typing was performed using the NIH standard micr0lymphocytotoxicitg test procedure. HI&& typing wa.zs performed using the technique of the 8th International Histocanpatibilitg workshop. Analysis of the &t-n.me response to the ragweed antigens revealed significant association of the antigen Ra5 response as measured by RAST and skin testing with HU Dr2 (P
48

COMPARISON OF METHACWOLINE BRONCHIAL REACZ’IVITY AND IgE LEVELS IN TWINS. R. Hopp, D.O., R. Townley, M.D., A.Bewtra, H.D. 3.Ash, Oina’ha, NE

Italy

Several clinical and imnmological Parameters were studied in 55 mxlozygotic cl&.) and 20 diqzotic (DZ) twin pairs in which at least one of the two mer&ers suffered fran atapic disease. llinical concordance yIs5 present in 50.0% of hiZ md in 30.9% of DZ, tiile only 38.5% of W and 13.& of ‘DZ had the same disease. 42,s of N end 16.7% of DZ were concordant for positive skin tests, while only 14.6% of MZ. and 6.B of L)Z had positive skin tests for the same allergefl. .IO significant difference was observed between m and DZ in the concordance for bronchial reactivity to exercise. The variance of total ;gE (Pi:IST), specific IgE (RAST), total I& and specific IgG (antigen bind(nephelanetry), ing assay) was higher in DZ than in W. A strong -lass-specific genetic effect was Particularly ::vident for total IgE and seen& to influence IgE and IgG the amount of specific IgE Ab. specific Aos were closely related and appeared influences. to depend rrrainly on enviranental .12 anu CL functional levels were shw to under40 a strong genetic control, C2 levels being si~liCicant Iy reduced in atopic twins but also in the corresponding healthy me&ers. No signliicant associations were observed between HLA A, B, anti C antigens and allergic diseases. Obtained resrllt-inilicate a carplex polyfactorial control oi ai iergic tiiseases. 46

CONCORDANCES IN ATOPIC TWINS. Sami L. Bahna, M.D., Dr.P.H., New Orleans, Louisiana Whether the development of a specific atopic manifestation or of hypersensitivity to a specific allergen is genetically determined is debatable. Thirty-two twin sets (10 monozygotic [MZ] d( 22 dizygotic [DZ], at ages l/2-13 yr E 5.03 who had manifest atopy in at least one twin were studied for concordance of the atopic manifestation, immediate-type skin reactivity to common environmental allergens by scratch testing, and serum total IgE level by RIA (PRIST). Manifest atopy in both twins was noted in 80% (%/lo) of MZ vs 59% (13/X!) of DZ sets; concordance of the same atopic manifestation was in 88% (7/8) of MZ & in 92% of allergy (12/13) of DZ sets. The distribution manifestations was similar in MZ & DZ sets. The intrapair difference in age at onset of allergy was <6 mo in 50% of MZ vs 32% in DZ. History of allergy in the immediate family was noted in all instances in which both twins had atopy but in only 64% in which one twin only had atopy (pO.3). Heredity does not seem to determine the type of atopic manifestation or the hypersensitivity to specific allergens.

To investigate the genetic influence on atopic diseases, including asthma, the methacholine inhalation challenge response (MICR) and cotal IgE levels (PRIST) of 61 pairs of monozygous twins (MZT) and 46 pairs of dirygotik twins (DZT) were studied. The twins were part of an

Allergic years.

Disease

Center

study and were 6 to 31

The

zygosity was determined by using a questionnaire, morphological markers and 9 blood genetic markers. A clinical history of atopic disease was 36% positively concordant in MZT, and 14.8% were discordant; while 19.5% of DZT had positive concordance and 21.7% were discordant. However. a X2 analysis of the casewise concordance showed no significant difference in MZT uh?n compared to DZT (p> 0.10). Log values are used for the IgE levels and methacholine areas. The IgE intrapair correlation coefficient for MZT was .825 (p< 0.01) and .52 (p (0.01) in DZT. The result of the MICR PS measured by the area under the dose response curve showed an intrapair correla-

tion coefficient of .67 (p(O.01) ia the c&e of MZT and .34 (p< 0.01) in DZT. A comparison of the intrapair correlation coefficients IgE and methacholine showed a signifi.cant ference (pcO.05) between MZT and DZT. heritability estimate 2(rMZT-rDZT) for

(r)

for difThe IgE is

.61 and .66 for MICR. The result greater higher

100

data suggests that IgE and MICR are the of genetic and environmental factors waith genetic influence as demonstrated bv the correlation in MZ twins.