DETECTION OF ANTI-HELICOBACTER PYLORI IgG ANTIBODIES IN HEALTHY SUBJECTS.
Introduction: Helicobacter pylori (H. pylori) are Gram - negative microaerophilic, spiral organisms. Factors such as family history of gastric disease, source of drinking water, number of siblings, sharing beds, and level of hygiene have been linked to acquisition of H. pylori infection. Most of the infected people do not have clinical symptoms. The study was planed to determine the level of anti-H. pylori IgG antibodies in the serum of healthy individuals.
Material and Methods: The study included 80 healthy subjects and was conducted in the Department of Immunology, University of Health Sciences Lahore. The studied population was divided on the basis of (a) eating food from outside home daily, twice a week or once a week, (b) using filtered or tap water for drinking, and (c) having family history of gastric ulcer or without family history of gastric ulcer. Level of anti H. pylori IgG antibody was determined by ELISA technique.
Results: Among 80 asymptomatic healthy individuals anti-H pylori IgG antibody was detected in 28 (35%) subjects who did not have these antibodies (p-value less than 0.001). Mean level of anti-H. pylori IgG antibodies was 43 +- 39.3 U/ml, 30.7 +- 37.3 U/ml and 14.9 +- 19.7 U/ml in subjects eating food from outside their homes once a week, twice a week and daily respectively. Statistically significant difference was observed in the level of H. pylori antibodies with different eating habits (p = 0.015). However no statistically significant difference was observed in the level of anti-H. pylori antiodies between two genders, individuals using tap water and filtered water for drinking and with family history of gastric ulcer.
Conclusion: H. pylori IgG antibodies were present in asymptomatic healthy individuals of both the genders.
Key Words: Helicobacter pylori, Antibody, ELISA.
Helicobacter pylori (H. pylori) are Gram - negative microaerophilic, spiral or gull - wing shaped organisms that can survive in stomach and duodenum. In 2005 Marshall and Warren received Noble prize on discovering the role of H. pylori in patients of gastritis and peptic ulcer disease.1 It is the most common chronic bacterial infection which occurs worldwide but its prevalence varies among countries and even in different populations of the same country. About 80% of the individuals infected with H. pylori in developing countries and about 50% in the developed countries are asymptomatic. Only 10% to 20% of H. pylori infected individuals develop gastric hyperacidity and peptic ulcer. H. pylori infection varies widely by geographical area, age, race, and socioeconomic status.2,3
Exact mode of transmission is not known but housing cluster, overcrowding, number of siblings, sharing beds, level of hygiene, family history of gastric disease, and source of drinking water; have been linked to acquisition of H. pylori. The organism has been cultured from stool samples of infected children and adults therefore, probably the organism is transmitted by fecal - oral route.2,4,5
Strong humoral and cellular immune response is mounted against H. pylori. Normal gastric acidity and its peristaltic movements inhibit bacterial colonisation but H. pylori can evade defense mechanisms and establish infection that may persist for life-time in the host. Survival of H. pylori in acidic stomach is dependent on urease which is an important virulence factor for gastritis2 along with cag pathogenicity island (cag PAI) vacuolation cytotoxin, and cytotoxin associated gene A (Cag A) protein.6,7 H. pylori also evade immune system by producing enzyme arginase which prevents nitric oxide (NO) production and therefore, it can survive within macrophages by interfering with lysosomal proteins.8
The organism also evades adaptive immune response by virulent factor (Vac A) which blocks antigen dependent proliferation of T - cells.9 Lipopolysac-charides (LPS) an flagellin (Fla A) of Gram negative bacteria activate TLR 4 and TLRS respectively but LPS and Fla A of H. pylori are 100 - 1000 TLR assist in evasion of immune system.10
Laboratory techniques for the detection of H. pylori include both invasive and non-invasive methods. Invasive methods include rapid urease test, histological identification and culture of the organism from gastric biopsy. Non-invasive methods are urease breath test, serological tests, detection of H. pylori stool antigen (HpSA) and H. pylori antibodies in urine and saliva.11 Urease breath test has advantages over serological analysis, but is expensive and time - consuming whereas serological techniques offer high sensitivity and specificity. It has been suggested that serological diagnosis was sufficient to detect H. pylori infection and it should be replaced by endoscopy - based procedures. Generally non-invasive tests are used for screening H. pylori in healthy population.12-14 Therefore, a study was planed to determine the level of anti-H. pylori IgG antibodies in the serum of healthy individuals and ELISA method was used for this purpose.
MATERIAL AND METHODS
It was an observational cross sectional study conducted at the Department of Immunology, University of Health Sciences Lahore during February 2010 - September 2010. It included 80 healthy subjects and the studied population was divided on the basis of (a) eating food from outside home daily, twice a week or once a week, (b) using filtered or tap water for drinking, and (c) having family history of gastric ulcer or without family history of gastric ulcer. Level of H. pylori IgG antibody was determined by ELISA technique using quantitative immunoassay kit from Bio check, Inc (U.S.A).
The data was entered and analysed using Statistical Pacage for Social Sciences 16 (SPSS - 16). Mean +- SD was given for quantitative variables. Frequencies, percentages and graphs were given for qualitative variables. Two independent sample t test was applied to observe group mean differences. A p-value of equivalent to less than 0.05 was considered statistically significant.
Eighty (80) healthy subjects included in this study comprised of 31 (38%) males and 49 (64%) females. Anti-H. pylori IgG antibodies were detected in 28 (35%) subjects while 52 (65%) subjects did not have these antibodies in the serum (Fig. 1). Subjects with anti-H. pylori IgG antibodies had their mean level of 71 +- 30 U/ml and it was 8.9 +- 4.1 U/ml in subjects who did have these antibodies. The difference in the level of anti-H. pylori IgG antibodies between these groups was statistically significant (p = 0.001) (Table 1). The level of anti-H. pylori IgG antibodies among males and females was 38.7 +- 40.5 U/ml and 25.7 H. pylori 31.3 U/ml respectively, the difference in the level of anti-H. pylori IgG antibodies between these groups was not statistically significant (p = 0.11) (Table 2).
Table 1: Number, mean and comparison of anti-H. pylori antibodies in
Antibody present###Antibody absent
Mean +- SD###Mean +- SD###p-value
(n = 28)###(n = 52)
71.4 +- 32 U/ml###8.90 +- 4.14 U/ml###less than 0.001
n = number of patients; p-value less than 0.05 = significant
Table 2: Number, mean and comparison of anti-H. pylori antibodies in healthy individuals between two genders.
Mean +- SD###Mean +- SD###p-value
(n = 31)###(n = 49)
38.7 +- 40.5 U/ml###27.5 +- 31.3 U/ml###0.11
n = number of patients; p-value less than 0.05 = significant
Mean level of anti-H. pylori IgG antibodies was 43 +-39.3 U/ml, 30.7 +- 37.3 U/ml and 14.9 +- 19.7 U/ml in participants who used to eat once a week, twice a week and daily fom outside home respectively. Statistically significant difference was observed in the level of H. pylori antibodies among individuals with different eating habits (p = 0.015) (Table 3). By applying post Hoc test statistically significant difference was observed in the level of H. pylori antibodies among participants who were eating from outside home once a week (p = 0.011). No statistically significant difference was observed between individuals using tap water or filtered water for drinking (p = 0.701). Among participants with family history of gastric ulcer, mean level of H. pylori antibodies was 30.2 +- 31.9 U/ml and it was 30.9 +- 36.6 U/ml who did not have family history of gastric ulcer. The difference in the level of anti-H. pylori IgG antibodies between these two groups was not statistically significant (p = 0.948).
Table 3: Number, mean and comparison of anti - H. pylori antibodies in healthy individuals with eating habits.
Once a week###Twice a week###Daily###
Mean +- SD###Mean +- SD (n =###Mean +- SD###p-value
(n = 30)###27)###(n = 23)
43.05 +- 39.3###30.7 +- 37.3###14.90 +-
U/ml###U/ml###19.7 U/ml###less than 0.001
In the present study, among 80 healthy subjects Anti-H. pylori IgG antibodies were detected in 28 (38%) subjects. The present study is not in agreement with Bakka et al15 who documented anti-H. pylori IgG antibodies in 66% of healthy subjects in the same age group. Studies showed variation in the prevalence of anti-H. pylori IgG antibodies in different parts of the world such as Rodrigues et al16 found 77% in Brazil, Gracia et at16 documented 17% in Orense, and Kirn et al18 showed 46% in South Korea among healthy individuals.
In the present study there was no statistical significant difference in the level of anti-H. pylori IgG antibodies in two genders. Our findings are similar to the studies of Bakka ct al,15 Rodrigues et al16 and Kirn et al18 who also could not find statistically significant difference in the level of H. pylori IgG anti-bodies in both the genders. In the present study the difference in the level of anti-H. pylori IgG antibodies between the participants who were using tap water or filtered water for drinking was not statistically significant (p = 0.701). The findings of Lin et al19 was similar to the present study because he also could not find statistically significant difference in the level of anti-H. pylori IgG antibodies among people who used tap water and river or well water for drinking but Nurgalieva el al20 linked drinking river water with high risk of H. pylori infection as compared to tap water.
In the present study, mean antibody level of anti-H. pylori IgG antibodies was 30.17 +- 31.9 U/ml and 30.9 +- 36.6 U/ml in subjects having family history of gastric ulcer and those who did not have such family history respectively and the difference in the level of anti-H. pylori IgG antibodies between these groups was not statistically significant. Escobar22 et al reported high level of anti-H. pylori antibody in subjects with family history of peptic ulcer disease as compared to those who did not have such family history. Salih21 et al found that children of mothers with gastric ulcer were at a greater risk of acquiring H. pylori infection and he suggested through physical contact mothers transmit H. pylori to their children.
In the present study, statistically significant difference was observed in the level of H. pylori anti-bodies among individuals with different eating habits (p = 0.015). Beguc el al23 documented increased prevalence of H. pylori infection in individuals who consumed food from street vendors and he supported that food prepared under unhygienic conditions as a source of transmission of this infection. On the other hand the study of Duynhove et al24 documented no direct evidence of food in the transmission of H. pylori.
It is concluded that anti-H. pylori IgG antibodies were found in asymptomatic healthy individuals of both genders.
The authors are grateful to the V.C of UHS for financially helping the project.
1. Per M Hellstrom. This year's Nobel Prize to gastroenterology: Robin Warren and Barry Marshall awarded for their discovery of Helicobacter pylori as pathogen in the gastrointcstinal tract. World J Gastroenterol 2006; 12: 3126-27.
2. Cehlay C, Peraz GI. Immune responses to Helicobacter pylori colonisation mechanisms and clinical out-comes. ClinSci 2006; 110: 305-14.
3. Rothenbacher D, Brenner H. Burden of Helicobacter pylori and H. pylori-related diseases in developed countries : recent developments and future implications. Microbes and Infection 2003; 5: 693-703.
4. Brown LM. Helicobacter pylori : epidemiology and routes of transmission. Epidemiol Rev 2000; 22: 283-97.
5. Kabir S. Detection of Helicobacter pylori in feces by culture, PCR and enzyme immunoassay. J Med Microbiol 2001; 50: 1021-29.
6. Szcepanik M. Interplay between H. pylori and the immune system. J Physiol Phannacol 2006; 57: 15-27.
7. Prinz C, Hafsi N, Voland P. Helicobacter pylori virulence Factors, host immune response and implications for therapeutic vaccination. Trends Microbiol 2003; 11: 135.
8. Ramarao N, Meyer TF. Helicobacter pylori resists phagocytosis by macrophages: quantitative assessment by confocal microscopy and fluorescence activated cell sorting. Infect Immun 2001; 69: 2604-11.
9. Boncristiano, Paccani M, Barone SR, Ulivieri C, Patrussi I., liver D, Amedei A.Rlios M, et al. The Helicobacter pylori vacuolating toxin inhibits T cell activation by two independent mechanisms. J Exp Med 2003; 198: 1887-1897.
10. Gewirtz AT, YuY, Krishna US, Israel DA, Lyons SL and Peek R M. Helicobacter pylori flagellin evades toll - like receptor 5-mediated innate immunity. J Infect Dis 2004; 189: 1914 20.
11. Meurer LN, Bower DJ. Management of Helicobacter pylori Infection. Am Fam Physician 2002; 65: 1327-36.
12. Andersen LP, Raskov H-H, Elsborg L.Prevalence of antibodies against heat stable antigens from Heliobacter pylori in patients with dyspeptic symptoms and normal persons APMIS 1992; 100: 779-89.
13. Andersen LP, Espersen F, Souckov A. Isolation and preliminary evaluation of a low - molecular - mass antigen preparation for improved detection of Helicobcicter pylori immunoglobulin G antibodies. Clin Diagn Lab Immunol 1995; 2: 156-9.
14. Jensen AKV, Andersen LP, Wachmann CH. Evaluation of eight commercial kits lor Helicobacter pylori IgG antibody detection. APMIS 1993; 10: 795-801.
15. Bakka AS, Salih BA. Prevalence of helicobacter pylori infection in asymptomatic subjects in Libyal.Diagn Microbiol Infect Dis 2002; 43: 265-68.
16. Rodrigues MN, Queiroz DM, Rodrigues RT, Rocha A M C, Luz C.R, Braga L.L.B. Prevalence of Helicobacter pylori infection in Fortaleza, Northeastern Brazil. Rev saude publica 2005; 39: 847-49.
17. Garcia RM, Diz PG, Benavides RAS, Seara JF. Prevalence of HeUcobacler pylori infection in the general adult population of the province of Ourense. Rev csp enfcrm dig 2006; 98: 241-48.
18. Kim JH, Kirn HY, Kim NY, Kirn SW, Kirn JG, Kim J.I et al. Seroepidemiological study of Helicobacter pylori infection in asymptomatic people in South Korea. J Gastroenterol Hepatol 2001; 16: 969-75.
19. Lin. D, Lin J, Chen C, Chen S, Chen W. Seroprevalence of Helicobacter pylori Infection Among School children and Teachers in Taiwan. 2007; 12: 258-64.
20. Nurgalieva Z, Malaty H.M, Graham D.Y, Almucham-betova. R, Machmudova.A, Kapsultanova.D, et al. Helicobacter pylori infection in Kazakhstan: effect of water source and household hygiene. Am J Trop Med Hyg 2002; 67: 201-6.
21. Salih B.A., Helicobacter pylori infection in developing countries. The burden for how long saudi journal of gastrology 2009; 15: 201-7.
22. Eccobar ML, Kawakami E. Evidence of mother to child transmission of Helicobacter pylori infection. Arq Gastroenterol 2004; 41: 239-44.
23. Begue RE, Gonzales JL, Gracian AC, Tang SC. Dietary factor associated with transmission of Helicobacter in Lima. Am J Trop Med Hyg 1998; 59: 637-40.
24. Duynhoven YTHP, Jonge R. Transmission of Helicobacter pylori: a role for food. World Health Organization 2001; 79: 455-60.
MEHREEN AHMAD, NADEEM AFZAL, AMNA HABIB ROMEEZA TAHIR, KHURSHEED RANA AND AFIA ABBAS
Department of Immunology, University of Health Sciences, Lahore - Pakistan
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|Date:||Jun 30, 2011|
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