Helicobacter pylori infection according to ABO blood group among blood donors in Kosovo

Introduction: Numerous studies have reported a high prevalence of Helicobacter pylori infection among healthy and non-healthy persons in different places. The Aim of the study is to investigate the seroprevalence of H. pylori infection among Kosovo’s Blood donor associated with ABO/Rhesus blood group. Methods: 671 blood donors are tested for H. pylori antibodies and results are classifi ed by way of donation, age, gender, blood groups and education level. Serum antibodies are analyzed by Enzyme Linked Fluorescent Assay test for H. pylori IgG with Biomerieux HPY-VIDAS. Results: The frequency of IgG antibody for H. pylori among healthy blood donors is 56.9%, there is not found any difference between voluntary and non-voluntary blood donors (57.4% respectively 56.3%)(OR=1.05; 95% CI 0.76 to 1.43; p=0.8). H pylori IgG antibodies positive are detected in 57.0 % ( 126 of 221) of women, compared with 56.9 % ( 256 of 450) of men(OR=0.99; 95% CI 0.72 to 1.38; p=0.96). Serpositive donors are older than seronegative ones (31.9 years, respectively 29.5 years, p=0.02). Mean value of IgG antibody of H. pylori is 3.61 with no signifi cant difference between males and females (3.72 respectively 3.44; p=0.2). The seroprevalence of H. pylori infection is similar among blood groups: O (57.4%), A (56.2%), B (59.6%), AB (51.4%), RhD positive (56.7%) and RhD negative (58.3%). Conclusions: The seropositivity of H. pylori is moderately higher in the non voluntary and familiar blood donors among the total Kosovo blood donors. There is not found a signifi cant relationship between infection with H. pylori and ABO/Rhesus blood group among blood donors. © 2011 All rights reserved


Introduction
Numerous studies have reported a high prevalence of H. pylori infection among healthy (1,2,3) and non healthy (4,5,6) persons in different places (7).H. pylori infection is recognized as the major cause of chronic gastritis (8), and a factor in the pathogenesis of peptic ulcer disease (9), gastric adenocarcinoma (10) and the gastric non-Hodkin lymphoma of mucosa-associated lymphoid tissue (MALT) (11).H. pylori infect more than half of the population in the world (10), but there are large diff erences in the prevalence of infection among ethnic groups (12,13).Infection occurs early (12) and H. pylori seropositivity increased with age (14,15).Lower socioeconomic status (crowded living conditions) is associated with high infection rates (4,15).Th e prevalence of H. pylori in rural communities is higher than in urban population (10).Transmission is by the oral-oral route, but some data reports for fecal-oral transmission route (16).H. pylori infection may, in some instances, be a zoonosis (6).Once H. pylori infection is acquired, it persists for decades and probably for life in untreated persons (13).Th e high prevalence of H. pylori infection 70%-90% is found among persons in developing countries (9,13) but, about 20% of H. pylori infected people develop clinically apparent conditions such as peptic ulcers or neoplasia.Education level was associated with negative H. pylori status (17).Based in above mentioned studies of many authors, H. pylori infection represents a highlighted problem in the healthy population of many countries.Because in Kosovo there are no studies in this area, the aim of this paper is the investigation of frequency of H. pylori infection in blood donors according to the type of blood donation (volunteers and familiarly), gender, age, education level and blood groups.Also it is evaluate mean value of IgG Antibody to H. pylori according to age group, gender and blood group among blood donors.Ten millilitres of blood sample is taken from each donor and the sera stored at -20° C until required.Th e assay principle combines a 2 step enzyme immunoassay sandwich method with a fi nal fl uorescent detection (ELFA).Th e commercial kit for detecting anti-H.pylori antibody is found to have a sensitivity of 98.10% (Confi dence interval 93.12%-99.77%)and a specifi city of 90.82 % (Confi dence interval 93.12%-99.77%).Interpretation of the test result is done as follows: the result lower than 0.75 is interpreted as negative, the result between 0.75-<1.00 is interpreted equivocal, and the values higher than >1.00 is interpreted as positive.In this study it is found that 48 samples of blood donors were equivocal to H. pylori antibody, therefore they are excluded and not evaluated.Also it is evaluated mean value of Ig G Antibody to H. pylori according to age group, gender and Blood group.Blood grouping is performed by slide agglutination test using monoclonal anti-A, anti-B, anti-AB and anti-D (Rho) antibodies.Statistics.For the parametric variables, values are expressed as mean ± DS.Comparison of means between groups is tested using a Student t-test.For all statistical tests conducted, the alpha level was set at 0.05.ANOVA-test is used for the analysis of mean diff erences of IgG H. pylori between blood group ABO and age-groups.A Chi-square test is used for the analysis of distribution of H. pylori infection donors according to the blood groups.Statistical analysis is performed using INSTAT 2 statistical soft ware system.

Results
From the total number of 671 tested blood donors for H. pylori infection, 382 or 56.9%, required IgG antibody for H. pylori, but there is not found diff erence between voluntary (57.4 %), and non voluntary blood donors (56.3%) (OR=1.05,95% CI 0.76 to 1.43, and p value 0.8) (Table 1).Serpositive donors are older 31.9 years, compared with seronegative ones 29.5 years, p is 0.02 (Table 2).Th e rate of H. pylori infection is not signifi cantly diff erent in male and female with anti H pylori Ig G antibodies detected in 57.0%(126 of 221) of women compared with 56.9% (256 of 450) of men (OR=0.99;95% CI 0.72 to 1.38; p=0.96) (Table 3).7).

Discussion
H. pylori infection has a relevant clinical importance and the testing for H. pylori Antibody helps in early detection of "silent" peptic ulcer (18).Previous studies reported a high frequency of H. pylori infection among voluntary blood donation (3).Akira et al found high seroprevalence of H. pylori infection in blood donors in four prefectures in Japan (19).Also Bernstein et al found in Canadian Indian population high prevalence of H. pylori infection (20).Th e prevalence of H. pylori infection continues to be higher in developing countries (17,21).Also there are found the signifi cant associations between H. pylori infection age, ethnicity, and socio cultural behaviours (13).Results reported by Sitas et al (22), presented that acquisition of H. pylori infection is related to childhood living conditions (7,23).Th e prevalence of infection was higher in the older age group than in younger age group, also low education standard was associated with the prevalence of infection (24).Based in above mentioned data and the unmet need for such a study in Kosovo we gave the idea to analyze our blood donors to H. pylori infection in this healthy group of population.In Kosovo voluntary blood donation is still insuffi cient to cover all patients who need transfusion treatment with blood products, so some donors used to be as familial donors which gave blood for their cousin     (18,6,25).Some data showed lower prevalence to H. pylori infection compared with our data which were: In Italy it was 45% (3), Germany 36.9% (26), Netherlands 35.5% (8), Australia 32% ( 14), Finland 25% ( 27), in Sweden was 18.2% (28), in Malaysia 14.2% (29).Th e similar data with ours are presented by other studies, for example: among Spanish blood donors it was 52.2% (30), blood donors in Guadeloupe 55.2% (2), and in Chinas blood donors 54.9% (31).Th e higher seroprevalence of H. pylori infection up to 60% is found in Brazil and Lebanon (68.2%, respectively 68.3%) (9,32).Our data showed that the seropositive donors were older than 31.9years, compared with seronegative ones 29.5 years.Similar data are presented and in Iran (33), when seropositive individuals are older than seronegative ones (24.5 years respectively 23.3 years).Analyzed blood donors by gender showed no difference among men and women (57.89% respectively 57.01%) of H. pylori infection.No sex difference to H. pylori infection is reported either by other authors (31).Also, no sex diff erence (17), is reported by EUROGAST study group which investigates asymptomatic subjects in 17 populations (24).But, the data off ered by Robertson et al (14), showed a lower frequency for seropositive men and women blood donors (35%, respectively 28%).Th e similar data with a lower frequency (16.8% in men and 13.6% in female) with no sex diff erence are found also, in Malaysian blood donors (male 16.8% and female 13.6%) (29), and in the Swedish blood donors (male 19% and female 16%) (28).
In  (29,30) or in symptomatic subjects (14,33,20,35).However some data (4, 8) showed a higher seropositivity to H. pylori in Rh D negative blood donors and in patients with gastrointestinal complaints (76.3%, respectively 84.5%) compared with our data (56.7%).In contrast to previous mentioned data and our data, Kanibal et al in Turkey demonstrated that H. pylori infection can be related to ABO blood group (34).Th ey found that blood groups O and A are more prone to H. pylori infection than other blood groups.
No statistically signifi cant diff erences are observed in mean values of Ig G antibody among diff erent groups (ABO and Rh D Factor) in blood donors in Kosovo.Th e data recorded from Martin et al (30), also have not found diff erences in mean value of IgG antibody among blood groups.

Conclusions
Th e seropositivity of H. pylori is moderately high in the non voluntary and voluntary blood donors, unrelated to gender.Th ere is not noted a significant relationship between infection with H. pylori and ABO/Rhesus blood group among Kosovo's blood donors.

Competing interests
Th is study is supported by the National Blood Transfusion Centre of Kosovo in Pristine.
In this study are evaluated 671 blood donors who underwent ABO/Rhesus blood typing and measurement of serum anti H. pylori IgG antibodies.Stored blood donor sera (450 males, mean age of 32.23 and range 18 to 65 years; 221 females, mean age of 28.18 and range 18 to 65 years; p is 0.0001) are collected from the March to April 2009 in Kosovo's Blood Transfusion Center.Age, gender, social class, educational level and ABO/RhD blood groups and IgG values are recorded.All donors are divided in two groups: voluntary donors and non voluntary or familial donors who gave blood for their relatives.

TABLE 1 .
Frequency of H. pylori infection among voluntary and non voluntary (familiar) blood donors

TABLE 2 .
Characteristics of blood donors according to age and infection with H. pylori

TABLE 3 .
Frequency of H. pylori infection among blood donors according to gender FIGURE 2. IgG seroprevalence of H pylori in 671 blood donors according to education level.

TABLE 4 .
Value of IgG Antibody of H. pylori among blood donors according to gender Frequency of IgG antibody to H pylori among blood donors according to age group p is 0.5.Also, it is not found a signifi cant diff erence between mean value of Ig G Ab of H. pylori in Rh D Positive donors compare with Rh D negative ones ( 2.05 respectively 2.69) p is 0.3 (Table

TABLE 5 .
Mean values of IgG Ab of H. pylori positive according to age group in Kosovo's blood donors

TABLE 6 .
Frequency of H. pylori infection among blood donors according to ABO blood group and Rh D Antigen

TABLE 7 .
Mean values of IgG Ab of H. pylori positive in relation to ABO blood group and Rh D Antigen in Kosovo's blood donors(familial).Th e topic of this study is to compare the frequency of H. pylori infection between these two groups of blood donors according to ABO group, Rh factor, gender, age and education level.Th e overall seroprevalence to H. pylori is 56.9% in healthy Kosovo's blood donors with no diff erence between voluntary and familial donors.Th is is a moderately high rate of H. pylori infection among healthy population.Th e data from previous studies presented large variations of H. pylori infection among blood donors in diff erent countries, but also and in diff erent regions in the same place.Previous studies done in Italy showed a diff erent prevalence to H. pylori infection among blood donors in different regions: in Bologna it was 42%, in Sardinia it was 43% and in Torino 47% (3)nd the high prevalence of H. pylori infection in donors with a low educational level(3).H. pylori infection distribution was similar among ABO blood groups and Rhesus factor in Kosovo's healthy blood donors.More studies have revealed no association between the ABO blood groups and H. pylori serological status either in healthy