macrolides have immunomodulatory effects as well as antibacterial effects . the immunomodulatory effect results in inhibition of t - lymphocyte proliferation and triggering of t - lymphocyte and eosinophil apoptosis [ 1 - 3 ] .
a trial of macrolide therapy for bronchial asthma , which is caused by eosinophilic and neutrophilic inflammation , was reported to yield promising results . in the trial , blood and sputum eosinophil counts , and sputum eosinophilic cationic protein levels
the results suggest that macrolides have a bronchial anti - inflammatory effect associated with decreased eosinophilic infiltration .
eosinophilic gastroenteritis ( ege ) is an uncommon disease characterized by eosinophilic infiltration of the gastrointestinal tract .
we report a rare case of ege , which relapsed on steroid reduction but improved following clarithromycin ( cam ) treatment .
a 52-year - old man was admitted to the hospital with abdominal pain , abdominal distension , and diarrhea .
a complete blood count revealed a white blood cell count of 13,990/mm with an eosinophil count of 8,674/mm ( 62.0% ) .
the serum immunoglobulin e level was 2,400 u / ml ( normal , 6 to 90 ) and a radioallergosorbent test was positive for numerous allergens , including common foods .
the serum level of c - reactive protein was 1.23 mg / l , and those of antinuclear antibody and anti - neutrophil cytoplasmic antibody were normal . computed tomography ( ct ) of the abdomen
endoscopic examination showed thickened and erythematous antral , duodenal , and ileal folds ( fig .
ascitic fluid revealed an abundance of mature eosinophils against a bloody background . no malignant cells or microorganisms
the patient was treated with prednisolone ( psl ) at 40 mg / day for 2 weeks which led to a rapid improvement in the symptoms and the eosinophil counts ( 0/mm ) .
psl was then tapered to 20 mg / day and the patient was discharged from hospital .
after discharge , the psl dose continued to be tapered uneventfully until the dose reached 3 mg / day , at which point the abdominal pain recurred and there was a rapid increase in the peripheral eosinophil counts ( 9,772/mm ; first relapse ) .
the psl dose was therefore increased to 20 mg / day , which caused a rapid improvement of eosinophilic counts ( 99/mm ) .
however , when psl was tapered again to a maintenance dose of 5 mg / day , eosinophil counts began to increase without symptoms ( second relapse ) .
because serum glucose levels rose to more than 200 mg / l during the psl treatment at a dose of 10 mg / day , it was determined that the dose could only be increased to 6 mg / day .
however , eosinophil counts continued to increase ( 351/mm ) , so cam at 400 mg / day was added after obtaining informed consent and this led to a gradual improvement of eosinophil counts ( 132/mm ) after 2 weeks .
the intention at that point was to taper the psl dose to 5 mg / day , but the patient was asymptomatic and therefore did not take psl for 3 weeks because of the potential for hyperglycemia .
although the patient was re - treated with psl at 5 mg / day , eosinophil counts increased rapidly ( 829/mm ) .
the dose of cam was accordingly doubled ( 800 mg / day ) , with the dose of psl maintained at 5 mg / day .
after 4 weeks , the eosinophilic count had improved ( 78/mm ) . by the end of the observation period
, the doses of psl and cam were reduced to 4 and 600 mg / day , respectively , with normal eosinophil counts .
follow - up enhanced ct revealed the improvement of the thickening of the small intestinal walls and ascites ( fig . 5 ) .
long - term use of cam did cause slightly loose stool as a side effect .
a review of the literature on treatment for ege showed that the first step is dietary restriction .
although an association is evident between food allergy and ege , the results of elimination diets are often poor .
the next step is the use of steroids , which have been a mainstay of treatment in ege .
the dosage of psl given at the onset of the condition is 20 to 40 mg / day for 6 to 8 weeks . about 90% of patients respond to this therapy .
if patients require high doses of psl for maintenance or are intolerant of steroid side effects , immunosuppressive drugs such as azathioprine may be helpful as steroid - sparing agents .
mast cell stabilizers , such as sodium cromoglycate , that prevent the release of histamine , platelet activating factors , and leukotrienes from mast cells , have also been reported to be effective .
montelukast , an antagonist of the leukotriene receptor cys - lt1 , was also found to be effective and useful as a steroid - sparing agent .
other case studies have investigated the effectiveness of new interleukin ( il)-4 and il-5 inhibitors such as suplatast tosilate   in ege and anti - il-5 monoclonal antibody mepolizumab in hypereosinophilic syndromes .
the present case suggests that cam was effective for the treatment of ege . during the second relapse ,
when there was a gradual increase in the eosinophil count , cam at 400 mg / day was effective in reducing the maintenance dose of psl . during the third relapse ,
when eosinophil counts increased rapidly , cam at an increased dose of 800 mg / day was effective .
however , the third relapse occurred during monotherapy with cam at 400 mg / day , suggesting that this form of treatment was not effective . the fact that cam treatment could reduce the maintenance dose of psl was advantageous in reducing the risk of steroid - induced hyperglycemia . for bronchial asthma , which is caused by eosinophilic and neutrophilic inflammation ,
a trial of macrolide therapy yielded promising results . in the trial , patients received 200 mg / day of cam for 8 weeks , after which symptoms , blood and sputum eosinophil counts , and sputum eosinophilic cationic protein levels were significantly decreased .
the authors concluded that cam had a bronchial anti - inflammatory effect associated with decreased eosinophilic infiltration .
although bronchial asthma could be controlled by only 200 mg / day of cam in that trial , a dose of 800 mg / day was needed for control of ege during the third relapse in the present patient .
one study showed that cam and erythromycin ( em ) suppressed the il-5-induced prolongation of eosinophil survival in a dose - dependent manner .
when eosinophils were cultured in the presence of il-5 with physiologic concentrations of em or cam ( both 10 g / ml ) , the effect of il-5 was almost abolished , and the morphologic changes in eosinophils observed by electron microscopy were consistent with apoptosis .
em and its derivatives also inhibit proliferation and induce apoptosis of t - lymphocytes that secrete il-5 .
in addition to immunomodulatory effects , macrolides also have steroid - sparing effects because of their influence on corticosteroid metabolism .
study evidence suggests that the macrolide mechanism of action in treating ege involves anti - eosinophilic effects , anti - t lymphocytic effects , and steroid - sparing effects ; however , because only one case is reported , more research is necessary before this treatment can be adopted .
 eosinophilic gastroenteritis ( ege ) is an uncommon disease characterized by eosinophilic infiltration of the gastrointestinal tract , which is usually associated with abdominal pain , diarrhea , ascites , and peripheral eosinophilia . 
 steroids remain the mainstay of treatment for ege , but symptoms often recur when the dose is reduced . 
 macrolides have immunomodulatory effects as well as antibacterial effects . the immunomodulatory effect results in inhibition of t - lymphocyte proliferation and triggering of t - lymphocyte and eosinophil apoptosis . 
 macrolides also have a steroid - sparing effect through their influence on steroid metabolism . 
 we report a rare case of ege , which relapsed on steroid reduction but improved following clarithromycin treatment . 
INTRODUCTION
CASE REPORT
DISCUSSION