recently , helicobacter pylori ( h. pylori ) infection has been increasingly reported to be inversely associated with allergic diseases , although some study groups proposed discrepancies in the data , i.e. improvement or no improvement in allergic symptoms after the eradication .
we by chance checked nonspecific serum immunoglobulin e ( ige ) and found a marked rise in its titers following h. pylori eradication therapy .
a 49-year - old japanese man , ex - smoker without allergic disorders , visited kamifukuoka - kyodo clinic checking for low serum pepsinogen ( pg ) levels : pg i 40.8 ng / ml , pg ii 15.7 ng / ml , and pg i : pg ii ratio 2.60 , suggesting possible gastric cancer .
gastrofiberscopic examination did not reveal gastric cancer , but showed atrophic gastritis with h. pylori infection , i.e. positive results for rapid urease test and pathologic findings .
the patient wanted to eradicate h. pylori , and a triple drug regimen using lansoprazole 60 mg / day , amoxicillin 1,500 mg / day , and clarithromycin 400 mg / day for 7 days was initiated in february 2008 .
pylori antibody titers and immunohematologic parameters , complete blood counts , leukocyte differentials , and serum levels of immunoglobulin ( igg , iga , igm , and ige ) were serially measured .
eight weeks later , a second endoscopic examination confirmed successful eradication : negative results for both rapid urease test and pathologic findings . at that time , the titer of anti - h .
pylori igg antibody , neutrophil counts , and monocyte counts had decreased . on the contrary , peripheral counts of lymphocytes , eosinophils , basophils , and platelets
in addition , serum levels of igg , iga , igm , and ige had all risen .
10 more weeks later , the level of serum ige increased to four times its pretreatment level : 306  485  1,325 u / ml ( normal < 170 ) . along with these increases , the number of peripheral eosinophils also increased to triple : 99  139  298 per l .
in addition , we pathologically evaluated ige - containing cells and mast cells in the gastric mucosa ( fig . 1 , fig .
the density of mast cells apparently increased in the antrum , although that of ige - containing cells did not show any difference on the posttreatment specimen .
the patient neither began to keep animals nor did he receive any additional medications , and was free from any signs of allergic disorders by december 2008 .
infiltration of both neutrophils and lymphocytes into the gastric mucosa is a well - known phenomenon among h. pylori - infected patients .
in addition , monocytes , eosinophils and basophils also have been reported to infiltrate into the gastric mucosa in h. pylori - infected persons .
these observations suggest that h. pylori infection can upregulate the peripheral numbers of such leukocytes in infected patients .
we therefore presume that eradication of h. pylori decreases the numbers of these leukocytes and of immunoglobulins in the peripheral blood .
the precise mechanism of this phenomenon is unclear , but the following is able to explain the phenomenon : ( 1 ) skewed differentiation of helper t cell seen in h. pylori - infected patients , ( 2 ) hygiene hypothesis , and ( 3 ) the influence of lansoprazole on serum immunoglobulins .
h. pylori infection is now accepted to skew t helper differentiation toward type 1 ( th1 ) property ( production of interleukin-2 , interferon- , and tumor necrosis factor - a ) that counteracts the th2-dependent process .
actually some cell contents of h. pylori have been reported to downregulate th2 inflammation in experimental models . as a result of successful eradication
, the liberation of th1 property could enhance humoral immunity to upregulate immunoglobulin production , and this regain may finally exert upregulation of serum ige and eosinophilic inflammation induced by the th2-dependent process . in recent decades , the decreased prevalence in infectious diseases had led to a rapid increase in the prevalence of allergic diseases especially in western societies , and such observation has been explained with the hygiene hypothesis .
exposure to some pathogens , including bacteria and viruses , is proven to induce th1 skew that could be preventive for the induction of allergic diseases through counteraction against th2 cells .
we stained ige - containing cells and mast cells in the pretreatment and posttreatment gastric mucosa . as a result ,
mast cells have been reported to involve gastric mucosal damage in patients with gastritis , especially those infected with h. pylori .
we thus presumed the decreased density of mast cells in the posttreatment specimen , we however could not confirm such decrease microscopically .
since mast cells involve allergic response in humans , this observation may represent h. pylori eradication - induced allergy . concerning serum immunoglobulins , we recently reported increases in serum igg and igm in h. pylori - infected patients treated with lansoprazole , suggesting the altering ability on th1 shift .
we however confirmed continuous increases in lymphocytes , eosinophils , basophils , igg and ige in the peripheral blood at follow - up .
since the patient was free from lansoprazole on follow - up , the continuous increases in both ige and eosinophil should be an aftereffect induced by h. pylori eradication .
this case presentation suggests that some patients are able to develop allergic disorders through h. pylori eradication . since a sole case presentation
can not be applied for an exact explanation for the phenomenon , further evaluations using sufficient numbers of patients should be performed .
 helicobacter pylori infection has been reported to be inversely associated with allergic disorders . 
 we by chance experienced a patient with atrophic gastritis who presented marked elevations of both nonspecific serum immunoglobulin e and eosinophil counts after h. pylori eradication . 
 a 49-year - old japanese man received eradication of h. pylori using lansoprazole 60 mg / day , amoxicillin 1,500 mg / day , and clarithromycin 400 mg / day for 7 days . 
 serum immunoglobulin e increased to more than four times its pretreatment level , 306  485  1,325 u / ml , and peripheral eosinophil counts increased to more than three times , 99  139  298 per l . 
 deducing from the current case , h. pylori eradication might develop allergic disorders in some patients . 
Introduction
Case Report
Discussion