Relationship Between Asthma and IgG Response to
Helicobacter pylori
Laalasa Varanasi, Betty Herndon, Shreya Lankala
Introduction
• According to the Asthma and Allergy Foundation of America,
nearly 25 million Americans suffer from asthma. The etiology
of asthma is not clearly known, but several triggers have been
implicated.
• Gastroesophageal reflux disease (GERD), which is often
associated with the microaerophilic organism Helicobacter
pylori, affects a significant portion of the population and has
been thought to trigger asthma exacerbations.
• GERD exists in patients with stable asthma, even in the
absence of esophageal symptoms.1 Numerous studies have
been performed regarding the prevalence of GERD in asthma
patients, but few have investigated the role of atopy in
antibody responses to H. pylori.
• IgE is a key immunoglobulin that is responsible for the mast
cell degranulation and airway hyperreactivity that
characterizes atopic asthma.3
• The immunologic hyperreactivity to antigens in atopic asthma
could have an effect on antibody responses to H. pyloriassociated GERD and should be investigated due to the
commonality of both asthma and GERD in today’s society.
UMKC School of Medicine
Results
• A significant percentage of severe asthmatics had
elevated serum IgE in spite of the likelihood that
many were being treated with steroid-containing
compounds as standard of care.
• Some asthmatics – particularly patients who are
atopic and have elevated serum IgE levels – are
hyperreactive to antigens.
Figure 3. Immunoglobulin E in all sera, mean and standard deviation
Figure 1. Titers of H. pylori and IgE on sera from the same patients
Methods
Samples:
• Sera from subjects diagnosed by the Truman Medical Center
Pulmonary Clinic as having severe asthma and sera from healthy
medical students and staff marked as controls
• Numbered, but without patient identification
• Declared exempt from IRB clearance by the University IRB
• In asthmatic sera, 44.83% of samples had high IgE titers
and12.06% had low IgE titers. Among controls, 8.3% of
samples had high IgE titers and 16.7% had low IgE titers.
• In asthmatic sera, 16.07% of H.pylori IgG titers were high and
26.7% were low. Control sera had no high titers, but 61.9%
had low H. pylori IgG titers.
• Seven of the 9 asthmatic subjects with high serum H. pylori
titers had high serum IgE titers also. Only one of the 13
asthmatic subjects with low H. pylori titers also had low IgE
(11.1%).
Summary
Rationale: To determine, in a population of asthmatics and controls, if
the H. pylori serum titer is related to atopy (reflected by the IgE titer).
Hypothesis: Sera of individuals with severe asthma will have elevated
titers of H. pylori IgG as opposed to controls.
Assays:
• Human IgE and H. pylori-specific ELISAs were run on sera from 58
asthmatics and 24 controls. Results were analyzed by titer based on a
450 nm read of 2.000 or greater (high), a read of 0.25 (low) and a +/read between those values.
• Significance and graphics were calculated using Statistica.
Clinical Relevance:
• Both asthma and GERD with H. pylori are prevalent in the population.
• The influence of H. pylori on lung problems is not often considered,
because the microaerophilic organism will not grow in the lung.
• Lung damage by aspiration of acidic gastric contents could
exacerbate the symptoms and disease progress in atopic patients.
Conclusions
Figure 2. Comparison of healthy controls with asthmatic patient sera, IgE and H. pylori
Caveats that might affect the data:
• Patient chart data did not accompany sera; no
information on which or how many were taking
steroidal drugs (possible ↓ in IgE titer)
• Control “lung healthy” population was not agematched to asthmatics
Strengths in the data:
• Asthmatic H.pylori titers 16.07% high 26.7% low
• Control H. pylori titers:
0% high 61.9% low
• 7 of the 9 asthmatic subjects with highest H. pylori
titers had high IgE
• 1 of the 13 asthmatic subjects with lowest H. pylori
titers had low IgE
• Seven of the 9 asthmatic subjects with high
serum H. pylori titers also had high serum IgE
titers. Only one of the 13 asthmatic subjects with
low H. pylori titers also had low IgE.
• The hypothesis was correct; a significantly greater
percentage of the severe asthmatic population’s
serum was positive for H. pylori compared to
student/staff controls.
• These results suggest that asthmatic atopy may
be associated with increased general antigen
reactivity in our population.
References
1. Harding, Susan M. "The Prevalence of Gastroesophageal Reflux in
Asthma Patients without Reflux Symptoms." Am J Respir Crit Care
Med. 2000 Jul;162(1):34-9.
2. Harding, Susan M. "24-hour Esophageal pH Testing in Asthmatics:
Respiratory Symptom Correlation with Esophageal Acid Events.” Chest.
1999 Mar;115(3):654-9.
3. Oettgen, Hans C. "IgE in Asthma and Atopy: Cellular and Molecular
Connections." J Clin Invest. 1999 Oct;104(7):829-35.