a 42-year - old man with hcv was referred to our hospital in august 2004 because of diarrhea and bloody stool .
ten years before admission , he had been diagnosed with total uc endoscopically and histologically .
colonoscopic examination revealed reddish and edematous mucosa with multiple erosions through the entire colon ( fig .
laboratory data showed thrombocytopenia ( 57,000/mm3 ) , asparate aminotransferase ( ast ) 124 iu / l , alanine aminotransferase ( alt ) 110 iu / l , and hepatitis c virus ( hcv ) rna ( genotype ib ) 757 kiu / ml .
after informed consent had been obtained , he was treated with peg - ifn--2a ( 90 g / week ) for improving both colonic and liver inflammation .
four weeks after initiation of peg - ifn therapy , his abdominal symptoms gradually subsided .
we performed intracellular cytokine assay with peripheral cd4 t cells before and after ifn therapy .
the ratio of t - helper ( th ) 1 ( ifn-?)/th 2 ( interleukin ( il)-4 ) increased ( 40.2 ) at 4 weeks after ifn therapy compared to that before ( 27.4 ) ( fig .
however , there was no significant difference of il-10 production from cd4 t cells between before and after ifn therapy .
he was uneventfully treated with peg - ifn--2a for one year . when last seen in november 2006 , he was still in remission of uc and his laboratory data showed a negative serum hcv - rna , which was suggestive of sustained virological response .
inf- , through its immunomodulatory function , could have an impact on pathways in the immune system .
therefore , the effect of inf- on the pathophysiology of ibd has been focused , because patients with ibd are characterized by imbalance of the th1/th2 cytokine response .
previous reports showed that a treatment with inf- might be a trigger for development of th1-related intestinal disease such as celiac disease and crohn 's disease , because inf- plays an important role in t cell differentiation towards a th1 type of immune response [ 5 , 6 ] .
regard , inf- is considered to have beneficial effects in the treatment of diseases characterized by excess th2 cells such as uc .
in fact , several clinical trials with ifn seem to be successful in chronic active uc [ 1 , 2 ] . however , the effect of inf- on uc remains controversial , because of some reports on the provoking onset and exacerbation of uc by treatment of inf- [ 7 , 8 , 9 ] . in this case
, we evaluated the change of th1/th2 ratio of cd4 t cells before and after inf- therapy .
the data on intracellular cytokine assay clearly demonstrated that ifn administration increased th1/th2 ratio of peripheral cd4 t cells , which was suggestive of shifting cytokine profile toward th1 .
in addition , our data showed that administration of peg - ifn--2a did not increase il-10 production from peripheral cd4 t cells .
thus , alteration of th1/th2 cytokine balance of peripheral cd4 t cells may be a biomarker for type 1 interferon therapy in patients with uc . in the future
, ifn therapy could be useful for patients with uc refractory to other conventional therapies by practical application of this biomarker .
 a 42-year - old man with chronic hepatitis c and ulcerative colitis ( uc ) was referred to our hospital in august 2004 because of bloody diarrhea . 
 he was clinically and endoscopically diagnosed with flare of uc . 
 after informed consent had been obtained , he was treated with peg - ifn--2a . 
 four weeks after initiation of peg - ifn therapy , his abdominal symptoms gradually subsided . 
 intracellular cytokine assay revealed that the ratio of t - helper ( th ) 1 ( ifn-?)/th 2 ( il-4 ) increased after ifn therapy . 
 three months after starting ifn therapy , colonoscopy revealed a normal mucosal pattern . 
 he was uneventfully treated with peg - ifn--2a for one year . when last seen in november 2006 
 , he was still in remission of uc . our intracellular cytokine data suggested that alteration of th1/th2 cytokine balance by ifn is one possible mechanisms of reducing intestinal inflammation in patients with uc . in this 
 regard , ifn therapy could be useful for some patients with uc refractory to other conventional therapies . 
Case Report
Discussion