S.R. Agarkhedkar, H.B. Bapat and B.N. Bapat
From the Allergy Research Institute, Sinhagad Road,
Vadgaon Budruk, Pune, 411 051, India and Department of Pediatrics,
MIMER Medical College,Talegaon Dabhade, Pune, India.
Correspondence to :Dr. H.B.Bapat, Allergy Research
Institute, Sinhgad Road,Vadgaon Budruk, Pune 411 051, Maharashtra,
India. E-mail:
[email protected]
Manuscript received: November 18, 2003, Initial
review completed: March 1, 2004;
Revision accepted: October 19, 2004.
Abstract:
Twenty-four patients of moderate persistent
perennial asthma with documented aggravation to severe persistent
asthma, during monsoon season in the past two years, were put on
specific elimination diet during August and September. The diet
was based on results of in-vitro allergy tests for a selected food
panel. On specific elimination diet, five patients improved to
mild persistent asthma and twelve patients improved to mild
persistent asthma with occasional exacerbations . Six patients
remained at moderate persistent asthma and only one patient
deteriorated to severe persistent asthma. These results indicate
that food avoidance may help in asthma control in children.
Key words: Allergy, Asthma, Food-allergens.
Allergic bronchial asthma is caused by
exposure to environmental and dietary allergens. Allergen avoidance is
considered to be an important aspect of management of allergic
asthma(1). Many studies show the beneficial effect of environmental
allergen avoidance(2). Regarding avoidance of food allergens, studies
are available only for neonates and infants in relation to later risk of
asthma(3). There is paucity of evidence dealing specifically with
avoidance of food allergens in the clinical management of childhood
asthma.
The purpose of this study was to evaluate possible
effect of a specific elimination diet (i.e., avoidance of food
items for which serum IgE titers were raised) in pediatric asthmatics
having seasonal aggravation.
Subjects and Methods
This study was carried out in pediatric patients of
bronchial asthma, attending the out patient department of a general
teaching hospital. Age of the children was in the range of 3 to 15
years. There were 14 males and 10 females.
All children had moderate perennial asthma. Fifteen
patients were receiving Step 2 and nine patients were receiving Step 3
treatment as per GINA guidelines(4). Previous two years records showed
that all of them deteriorated to severe persistent asthma during the
peak monsoon months of August and September and needed upgradation to
Step 4 treatment.
Total IgE levels and specific IgE titers for all
foodstuffs listed in the Table I were measured in all children.
The test was performed on clear serum separated from 5 mL venous blood.
Total serum IgE was measured by a two stage enzyme immuno-assay sandwich
technique. The enzyme lable used was penicillinase manufactured by
Hindustan Antbiotics, India. The iodometric method of penicillinase
assay introduced by Pollock(5) and modified by Ghosh and Borkar(6) was
employed to measure bound enzyme. Penicillin, starch, iodine, gelatin
and phosphate buffer formed the substrate mixture. Time taken for
decolorisation of substrate mixture was plotted against different
dilutions of IgE standards to get a reference curve.
For Specific IgE Titers (Allergy Research Institute
Specific IgE Titers: ARISIT), extracts of
foods were prepared at Allergy Research Institute, Pune as per standard
methods(7). Fractions having maximum molecular weight were collected by
passing extracts through a ceralose 6 B column (bead size 40 to 190
microns). ELISA was carried out, employing penicillinase enzyme for
conjugate.
Sandwich technique was used and iodometric method
mentioned above was followed with penicillin, starch, iodine, gelatin
and phosphate buffer forming the substrate mixture. Specific IgE titre
was calculated from the time taken in seconds for decolorisation of
iodine in the substrate for two different dilutions of serum, a ratio
serving as an index of binding of antigen and corresponding specific IgE
if present in the serum. At our institute mean specific IgE titers in
asymptomatic, non-atopic individuals for each antigen included in the
food panel was 1.07 with standard deviation of .002. Specific IgE titers
higher than 1.085 were considered positive.
Patients were asked to avoid all food items, which
tested positive and parents were asked to maintain a food diary. The
tests were carried out in middle of July and patients were asked to
start food avoidance immediately.
All patients were called for 8 follow up visits
during study period, i.e., weekly. They were instructed to
contact for any aggravation of symptoms. If they could not contact the
doctor they were asked to make a written note of aggravation and
medication required to control the aggravation.
Results
Twenty four patients having documented deterioration
in control of their perenial asthma during months of August and
September in two previous years were selected for the study. Their ages
ranged from 3 yrs to 15 yrs and there were 14 males and 10 females.
Normal range of total Ige at our Allergy Research
Institute has been found to be 150 ng/mL to 400 ngm/mL (with mean of 232
ng/mL and SD 34.7 ngm/mL). Total IgE level in all patients was more than
1500 ng/mL.
The result of specific IgE titers against different
food items is presented in Table I.
TABLE I
Specific IgE Titers in Study Subjects Against Different Food Stuffs.
Food Item |
IgE raised
n |
Food item
|
IgE raised
n |
Food item |
IgE raised
n |
Food Item |
IgE raised
n |
Cereals |
|
|
|
|
|
|
|
Rice |
20 (83%) |
Wheat |
12 (50%) |
Maida |
9 (38%) |
Maize |
7(29%)
|
Jowar
|
4 (17%) |
|
|
|
|
|
|
Pulses |
|
|
|
|
|
|
|
Tur Dal |
11(46%) |
Chana Dal |
19 (79%) |
Masoor Dal |
4 (17%) |
Moong Dal |
19(79%) |
Udid Dal |
23(96%) |
Soyabean |
5 (21%) |
Back-eyed
beans
|
19(79%) |
|
|
Beverages |
|
|
|
|
|
|
|
Tea |
1 (4%) |
Coffee |
2 (8%) |
Cocoa |
5 (21%) |
|
|
Vegetables |
|
|
|
|
|
|
|
Carrot |
21 (88%) |
Potato
|
20(83%) |
Navalkol |
18(75%) |
Cauliflower |
19(79%)
|
Cabbage |
8(33%)
|
Cucumber |
21(88%) |
Tondli |
15(63%) |
Onions |
6(25%) |
Ridge-gourd |
17(71%) |
Cluster-beans |
18(75%) |
Red-pumpkin |
11(46%) |
White-
pumpkin |
21(88%) |
Brinjal |
22(92%) |
French-beans |
18(75%)
|
|
|
|
|
Fruits |
|
|
|
|
|
|
|
Apple
|
21(88%) |
Banana |
20(83%) |
Mosambi |
19(79%) |
Lemon |
19(79%) |
Tomato |
2(8%) |
Grapes |
21(88%)
|
Orange |
4(17%) |
Pineapple |
19(79%)
|
Papai |
7(29%) |
Kokam |
19(79%) |
Guava |
19(79%) |
Sugarcane |
18(75%) |
Water-melon |
19 (79%) |
Musk-melon |
23(96%) |
Alphonso |
19(79%) |
Chikku |
18(75%) |
Oils
|
|
|
|
|
|
|
|
Groundnut |
10 (42%) |
Coconut |
5 (21%) |
Til |
9(29%) |
Safflower |
8(33%) |
Mustard |
9(29%) |
Cotton-seed
|
8(33%) |
Sunflower |
9(29%) |
|
|
Non-Vegetarian
|
|
|
|
|
|
|
|
Egg |
4(17%)
|
Mutton
|
19(79%) |
Chicken |
20 (83%) |
Prawns |
15 (75%) |
Pomphret |
17(71%) |
Rohu |
14 (58%) |
Surmai |
19(79%) |
|
|
Milk Products
|
|
|
|
|
|
|
|
Milk |
6(25%) |
Cheese |
20 (83%) |
Curd |
17 (71%) |
Butter |
6 (25%)
|
Ghee |
6(25%) |
|
|
|
|
|
|
Spices
|
|
|
|
|
|
|
|
Garlic |
14 (58%) |
Ginger |
11(46%)
|
Red Chilly |
3 (12.5 %)
|
Green Chilly |
8 (33%) |
Turmeric |
12 (50%) |
Jira |
20 ( 83%) |
Coriander
|
20 (83%) |
Black-pepper
|
22 (92%) |
Hing |
15 (63%) |
|
|
|
|
|
|
Majority (83%) of children had raised specific IgE
titers against rice whereas only four (17%) children had raised
antibodies against jowar. Among the pulses in vitro hypersensitivity
against masoor dal was present in only 17% as compared to 96% and 79%
against udid dal and chana dal or moong dal respectively. In the
vegetable category, most children were allergic to brinjal while only
25% were allergic to onions. Among the fruits all but one child had
raised titer against musk melon while only two had raised titer against
tomato. In the cooking oil group antibody titer for groundnut oil was
seen to be positive in 42% of children while corresponding figure for
coconut oil was 21%. Among non-vegetarian items antibody titer against
chicken was positive in 83% but egg was positive in only 17% children.
After elimination diet patients were classified on
basis of their clinical status as per GINA guidelines(4) and their
clinical status in August and September of current year was compared
with that of previous two years during same months.
During August and September of previous two years,
all patients had deterioration of asthma control to severe persistent
asthma (Group IV).
During August and September of current year while on
specific elimination diet five patients had mild persistent asthma with
no aggravation (Group I ) and twelve had mild persistent asthma with
occasional aggravation controlled with beta agonist (Group II ). Six
patients did not deteriorate to severe persistent asthma and remained in
Group III. Only one patient deteriorated to severe persistent asthma
during current year while on specific elimination diet.
Discussion
In the present study the distribution of clinical
status during August and September of the current year with specific
elimination diet was compared to that during August and September of the
previous years when none of the patients were on specific elimination
diet and had deteriorated. The results indicated that deterioration
could be prevented in most patients with specific food avoidance in the
vulnerable period. There were certain limitations of the present
study.The study was based on speculation that the children would have
progressed to severe persistent asthma during August and September
without specific elimination diet.However the records of these children
showed that they had worsened during these months in the last two
years.There was no other obvious reason that they should have not
deteriorated this year while age advanced only by one year. Another
limitation of the study was lack of control group and a small sample
size which precluded any valid statistical interpretation
The beneficial effect of food avoidance in our cases
could possibly be explained by the concept of Total Allergen Load
introduced by Feinberg(8) and later highlighted by Sheldon (9). Sheldon
observed that in comparison with sensitivity to inhalants, sensitivity
to foods is more common in infants and children and it is therefore
important not to overlook food allergy. Food allergies need not be
perennial and patients may manifest symptoms only during seasons when
these foods are available or consumed in large amount affecting the
allergen load(9). Symptoms occur when mediators are released on
degranulation of mast cells. Degranulation results from binding of the
double bond of antigen-specific IgE receptors,present for that
particular antigen on the mast cells. Thus, degree of response is
directly related to product of the dose of antigen with number of
antigen-specific IgE receptors.
Each individual antigen on its own may not be able to
produce much reaction since number of antigen-specific receptors for
that particular antigen are few. The simultaneous exposure to a number
of such antigens, however, would bind enough antigen-specific IgE
receptors on a greater number of mast cells and result in symptoms(10).
Overall the results of this study suggested, that
children with asthma having seasonal exacerbation have evidence of
in-vitro hypersensitivity to a wide variety of food antigens and the use
of a specific elimination diet might prevent the seasonal exacerbation.
These preliminary results should be confirmed by large well-designed
controlled trials.
Acknowledgement
Authors are grateful to Dean, M.I.M.E.R. Medical
College, Talegaon, Dabhade, Pune, India for the permission to conduct
study and for providing other facilities
Contributors: BNB provided the concept and
framework of the study. SRA conducted the study with HBB and drafted the
manuscript. SRA shall act as guarantor.
Funding: None.
Competing interest: None.
Key Messages |
• Children with seasonal asthma have evidence of in-vitro
hypersensitivity to wide variety of food antigens
• Use of specific elimination diet might help in better
control asthma in these children.
|
|
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