Infliximab (Remicade, Mantecorp, Malvern, PA), a potent anti-inflammatory agent, is a chimeric immunoglobulin G1 monoclonal antibody, 75% human and 25% murine, that binds to tumor necrosis factor-α with high affinity and specificity, neutralizing its activity (1).
The first case in the literature that used this new medication in Crohn disease focused on a 12-year-old girl, who was successfully treated in 1993 (2). Since that publication, many trials studying the use of infliximab in adults with Crohn disease and ulcerative colitis have been published, with a proven efficacy in those with moderate-to-severe Crohn disease who have had an inadequate response to conventional therapy, as well in those with fistulizing disease (3–8). There are also studies showing positive effects of infliximab use for ulcerative colitis, including clinical response and clinical remission, discontinued use of corticosteroids, mucosal healing, and postponing or averting the need for colectomy (9–12). The studies (13–28) published for children and adolescents treated with infliximab have shown good results for both Crohn disease and ulcerative colitis.
The aim of the present study was to evaluate the response to infliximab in children and adolescents with Crohn disease and ulcerative colitis.
PATIENTS AND METHODS
This was an open-label prospective clinical trial. The inclusion criteria for the study were children and adolescents with Crohn disease or ulcerative colitis who were outpatients of the Federal University of São Paulo with a clinical indication for infliximab because of Crohn disease refractory to conventional treatment (corticosteroid, mesalazine, and immunomodulator) or they were corticosteroid dependent; or ulcerative colitis refractory to conventional treatment (corticosteroid, mesalazine, and immunomodulator) or they were corticosteroid dependent. Exclusion criteria were tuberculosis diagnosis and infections.
Corticosteroid-refractory disease was defined as no change in clinical features after 8 weeks of corticosteroid (prednisone) taken at a dose of 2 mg · kg−1 · day−1. Corticosteroid dependence was defined as the relapse of clinical features during dose tapering, preventing its discontinuation.
Early disease onset was arbitrarily defined as disease duration <2 years from the time of diagnosis, whereas late disease onset required a >2-year history of documented intestinal inflammation, as published by Kugathasan et al (14).
Eligible patients were enrolled between April 2004 and June 2006. The protocol was approved by the ethical committee board of the Federal University of São Paulo. The patients or their legal guardians signed the informed written consent after they were given information and warning about the advantages and possible adverse effects of therapy.
The treatment of infliximab (Remicade) consisted of the administration at a dose of 5 mg/kg in an induction regimen at weeks 0, 2, and 6 (28). The same dose was scheduled in maintenance therapy at 8-week intervals (28), for a total of 2 doses, at weeks 14 and 22. The medication was given by intravenous infusion for at least a 3-hour period. Patients were premedicated, 30 minutes before the infliximab application, with oral paracetamol (Tylenol) at a dose of 10 mg/kg and intravenous diphenhydramine (Benadryl) at a dose of 1 mg/kg. These medications were used to prevent side effects and the formation of antibodies against infliximab. The dilution and application of the infliximab was according to the manufacturer's protocol.
All of the patients underwent purified protein derivative tuberculin and chest radiographs before starting the infliximab therapy to exclude tuberculosis (16).
Efficacy of Infliximab
The response to infliximab treatment was determined by clinical manifestations, activity indices of inflammatory bowel disease (IBD) in weeks 0, 2, 6, 14, and 22, and the reduction or suspension of corticosteroid use through weeks 14 and 22. Therefore, the present study actually evaluated the results of 4 infliximab infusions at 0, 2, 6, and 14 weeks.
Clinical manifestations were abdominal pain, diarrhea, rectal bleeding, and extraintestinal symptoms, such as arthropathy, oral ulcer, and mood. The response to infliximab for clinical manifestations was categorized as remission, clinical improvement, or no response up to week 22 (29). Remission was defined as the cessation of clinical manifestations, clinical improvement was defined as a reduction but not cessation of clinical manifestations, and no response was defined as the lack of a reported change in clinical manifestations (29).
The activity indices of IBD were the Pediatric Crohn Disease Activity Index (PCDAI) (30) for Crohn disease, the Lightiger Colitis Activity Index (LCAI) (31) and the Pediatric Ulcerative Colitis Activity Index (PUCAI) (32) for ulcerative colitis, and the modified Harvey-Bradshaw Index (33) for Crohn disease and ulcerative colitis.
The PCDAI was calculated by clinical parameters, including abdominal pain, frequency of stools per day, patient general well-being, weight, height, presence of abdominal mass, rectal fistula and/or fissure, and extraintestinal manifestation, as well as laboratory parameters, including hematocrit, erythrocyte sedimentation rate, and albumin. Scores ≥30 indicated moderate to severe activity, scores ranging from 11 to 30 indicated mild activity, and scores ≤10 indicated inactive disease.
The LCAI was based on the number of stools per day, nocturnal diarrhea, visible blood in stool, fecal incontinence, abdominal pain or cramping, general well-being, abdominal tenderness, and the need for antidiarrheal drugs. Scores ≥10 indicated no response, whereas scores <10 indicated response but no remission, and scores ≤2 indicated remission.
The PUCAI evaluated abdominal pain, rectal bleeding, stool consistency of most stools, number of stools per 24 hours, nocturnal stools, and activity level. Scores ≥65 indicated severe activity, from 35 to 64 indicated moderate activity, from 10 to 34 indicated mild activity, and <10 indicated no activity.
The modified Harvey-Bradshaw Index was evaluated by number of liquid stools per day, abdominal pain, general well-being, complications (eg, arthralgia, skin or oral ulcers, iritis or uveitis, anal complications), abdominal mass (for Crohn disease), or rectal bleeding (for ulcerative colitis). Indices ≥4 indicated active disease.
The efficacy of infliximab was also evaluated by the reduction or suspension of corticosteroid use at any time up to week 22.
The statistical analysis was made using the Jandel SigmaStat Statistical program (Jandel Corporation, San Rafael, CA). Data were presented as mean ± standard variation and median (percentiles 25–75) values. Before (time 0) and after (2, 6, 14, and 22 weeks) statistical comparisons were made using the Mann-Whitney U test. Statistical testing used a 0.05 level of significance. The study of corticosteroid reduction in milligrams per kilogram per day at 0, 14, and 22 weeks was done using analysis of variance for a randomized complete block. It was necessary to use the transformation of the square root to meet the views of normality and homoscedasticity (error variance being constant during all weeks). The Tukey multiple comparison procedure was used to compare pairs of weeks. The comparison between groups with early and late disease onset using the Harvey-Bradshaw Index in weeks 0, 14, and 22 was made by analysis of variance for repeated measures. This statistical analysis was also performed to compare the Harvey-Bradshaw Index in weeks 0, 14, and 22 between the groups who were using 3 medications (mesalazine, azathioprine, and corticosteroid) and 2 medications (mesalazine and azathioprine). We also evaluated the comparison between 2 groups: children (1–10 years old) and adolescents (11–19 years old) in weeks 0, 14, and 22. The comparison of both groups (children and adolescents) using the Harvey-Bradshaw Index in weeks 0, 14, and 22 was made using analysis of variance with repeated measures.
The study population was composed of 21 patients having IBD, with 14 (66.7%) having Crohn disease and 7 (33.3%) having ulcerative colitis. The age of the patients at the first infusion ranged from 1 to 19 years, with a mean age of 11.5 ± 4.8 years and a median of 12.0 (8.0–14.2) years. Of the patients, 9 (42.9%) were female and 12 (57.1%) were male. The anatomic distribution of the disease was variable. Only 1 patient (number 10) had undergone a previous surgical resection. The patient characteristics are summarized in Table 1.
All of the patients experienced improvements in clinical manifestations after the first infliximab infusion, as follows: a decrease in the frequency of stools and the amount of blood in stools, the cessation of abdominal pain, and the resolution of extraintestinal symptoms, such as oral ulcers, arthopathy, and improved mood. Clinical manifestations categorized as remission, clinical improvement, and no response at week 22 were experienced in 85.7% (18/21), 14.3% (3/21), and 0% (0/21) of the patients, respectively.
Activity Indices of Inflammatory Bowel Disease
The PCDAI value decreased with statistical significance from the first infusion (time 0) to weeks 2, 6, 14, and 22 (Fig. 1) from 31.9 ± 13.4 (time 0) to 18.5 ± 14.3 at week 2 (P = 0.017), 13.3 ± 12.2 at week 6 (P = 0.003), 8.9 ± 11.1 at week 14 (P < 0.001), and 6.4 ± 8.9 at week 22 (P < 0.001). At week 22, 11 of 14 (78.6%) patients with Crohn disease had no active disease.
Of the patients with ulcerative colitis, 7 (100%) had clinical remission documented by LCAI at week 22, with statistically significant decreased values from baseline to values at weeks 2, 6, 14, and 22 (Fig. 1) from 9.1 ± 2.6 (time 0) to 4.7 ± 2.2 at week 2 (P = 0.006), 3.1 ± 2.7 at week 6 (P = 0.001), 2.1 ± 1.6 at week 14 (P < 0.001), and 0.7 ± 2.6 at week 22 (P < 0.001).
The mean PUCAI value of the ulcerative colitis population decreased statistically when comparing the index at time 0 to the index at weeks 2, 6, 14, and 22 (Fig. 1) from 50.0 ± 16.8 (time 0) to 23.5 ± 13.7 at week 2 (P = 0.007), 10.0 ± 7.6 at week 6 (P < 0.001), 6.4 ± 5.5 at week 14 (P < 0.001), and 5.0 ± 7.0 (P < 0.001) at week 22. According to the PUCAI, 5 of 7 (71.4%) patients had no active disease at week 22.
There was no active disease in 16 of 20 (80%) patients using the Harvey-Bradshaw Index at week 22, with a statistically decreased index from time 0 to weeks 2, 6, 14, and 22 (Fig. 1) from 8.1 ± 3.0 (time 0) to 4.4 ± 3.9 at week 2 (P = 0.002), 2.1 ± 2.4 at week 6 (P < 0.001), 1.4 ± 2.4 at week 14 (P < 0.001), and 1.0 ± 1.9 at week 22 (P < 0.001). The Harvey-Bradshaw Index was not calculated in 1 patient. It was not possible to evaluate the number of liquid stools per day for this patient because he had a colostomy.
There was no statistically significant difference between early and late groups disease onset using the Harvey-Bradshaw Index in weeks 0, 14, and 22 (P = 0.747).
The comparison between groups who were using 3 medications (mesalazine, azathioprine, and corticosteroid) and 2 medications (mesalazine and azathioprine) using the Harvey-Bradshaw Index in weeks 0, 14, and 22 showed no statistically significant difference (P = 0.290).
In the beginning of treatment (week 0), the child group had a higher measure of Harvey-Bradshaw Index compared with the adolescent group (P < 0.001). There were also differences in the response to therapy between both groups (children and adolescents). The reduction of Harvey-Bradshaw Index from week 0 to week 14 was statistically greater in the child group than the adolescent group (P < 0.001). There was also a statistically greater reduction of this index from week 0 to week 22 in the child group when compared with the adolescent group (P < 0.001). There was no difference between the reduction in the Harvey-Bradshaw Index from week 14 to week 22 when both groups were compared (P = 0.690).
In the beginning of treatment (time 0), 71% (15/21) of the patients were corticosteroid dependent. The level of corticosteroid administration decreased in 15 of 15 (100%) patients who were treated with this medication. Daily corticosteroid dose decreased statistically from time 0 to week 14 (P < 0.001) and from time 0 to week 22 (P < 0.001). There was no significant reduction of corticosteroid from week 14 to week 22 (P = 0.212). Corticosteroid was completely discontinued in 6 of 15 (40%), up to week 22. The median (percentiles 25–75) of daily corticosteroid in milligrams per kilogram of the remaining patients who were receiving corticosteroid (9/15) in week 22 was 0.25 (0.14–0.39).
In developing countries where the Western lifestyle is spreading, the corresponding rates are increasing and indicate an environmental influence in the genesis of IBD (34). Whereas studies of IBD prevalence in industrialized countries, such as North America, increased rapidly in the latter half of the 20th century, the prevalence, incidence, and mortality rates in Brazil are unknown, although regional reports have described an increase in the number of new cases of Crohn disease and ulcerative colitis (34).
The present study showed our first experience in Brazil with the beneficial effects of infliximab on Crohn disease and ulcerative colitis in children and adolescents refractory to conventional therapy. Infliximab induced clinical improvement and decreased the levels of activity indices of IBD in most of the patients, and decreased the corticosteroid dose.
All of the patients had improvements in their symptoms after the first infliximab infusion, as reported by Serrano et al (22) in 15 children with Crohn disease and 3 with ulcerative colitis who had decreases in the frequency of stools and the amount of blood in stools, and resolution of extraintestinal symptoms such as arthropathy, malaise, and skin manifestations. A study from Denmark (23) including 24 children with Crohn disease reported a complete response in 8 (33%) patients, 10 (42%) with a partial response, and 6 (25%) with no response at 1 month after the first infusion. Three months after the beginning of treatment, 7 (29%) patients had a prolonged response. Another study with 12 pediatric ulcerative colitis patients (24) found that all of them had a favorable response at 2 weeks after the first infusion of infliximab, with 9 patients having a complete resolution of symptoms and 3 having partial improvement. Additionally, 8 patients were considered long-term responders, defined as patients who did not require additional therapy, such as cyclosporine or colectomy, during the follow-up of at least 6 months after the first infusion.
The activity indices of IBD are suitable for research to facilitate patient stratification by disease severity, and longitudinal indices scores may provide a numerical measure of response to therapeutic regimens, such as infliximab use. We described decreases in 4 activity indices of IBD after infliximab therapy up to 22 weeks. Some of these indices were used to analyze the infliximab response for different periods of treatment. Baldassano et al (15) documented that 50% of the 21 children who received a single infusion of infliximab improved in their PCDAI scores by week 2, and 30% of them improved by week 12. All of the patients achieved a clinical response and 10 (48%) patients achieved clinical remission at some time during the observation period. Kugathasan et al (14) studied 15 children who received 1 dose of infliximab, showing that 14 (94%) patients had a significant decrease in PCDAI scores by week 4 and 10 children had clinical remission by week 10. In the study of 19 children and adolescents by Hyams et al (13), a significant decrease in the PCDAI was noted 4 weeks after the first infusion. A study published in Italy (17) with 22 children achieved a statistically significant decrease in the PCDAI during 18 weeks of study. Another publication from Italy (16) found decreases in the PCDAI levels of 18 pediatric patients with Crohn disease analyzed after 8 weeks of treatment, and the index remained lower after 6 months than it was at the beginning of treatment. The REACH study (21) (a randomized, multicenter, open-label study to evaluate the safety and efficacy of anti-TNF chimeric monoclonal antibody (infliximab, Remicade) in pediatric subjects with moderate to severe Crohn disease) found efficacy of infliximab in children with decreases in the mean PCDAI scores from baseline to weeks 10, 30, and 54.
The first report on the use of infliximab in pediatric patients with ulcerative colitis was published by Mamula et al (25), showing that the median LCAI decreased between the baseline and the level at 2 days and 2 weeks after the first infusion. Additionally, 6 of 9 patients (66%) had no active disease at 2 weeks after the infusion of infliximab. The authors from another study (27) reviewed 14 patients with ulcerative colitis who had LCAI at a baseline of ≥11. Of these 14 patients, 9 experienced response to infliximab with LCAI scores ≤2.
Two studies used the modified Harvey-Bradshaw Index to evaluate the response to infliximab in pediatric patients with Crohn disease. Cezard et al (19) documented that all 21 patients with severe Crohn disease had improvements in symptoms after the second infusion of infliximab. The Harvey-Bradshaw Index decreased from day 0 to day 45 and also decreased 3 months later. Lamireau et al (20) performed a study in 88 children and adolescents with Crohn disease and noted a significant decrease in the modified Harvey-Bradshaw score from day 0 to day 90.
Although in the beginning of the treatment 71% of the patients were corticosteroid dependent, in the present study, daily corticosteroid dose was tapered from week 0 to week 14 and also from week 0 to week 22. The level of corticosteroid dose decreased in all of the patients (15/15) who were treated with this medication and stopped in 40%, up to week 22. Studies about infliximab therapy in pediatric populations are different concerning, for instance, number of patients, number of infliximab infusions, and also how the dose of corticosteroid was analyzed, milligrams per day or milligrams per kilogram per day. According to Hyams et al (13), the level of corticosteroid decreased during the initial 12-week observation period, but the variability in infliximab infusion schedules (1–3 infusions) limits comparison with our study. Also, in some other studies (20,22,24) patients received a variable number of infliximab infusions. Borrelli et al (16) showed that all of the patients stopped corticosteroids within 4 weeks after beginning the infliximab infusion. In the study by Mamula et al (25), corticosteroid therapy was discontinued in 66% of the patients after the first infusion. The REACH study (21) showed that the average daily corticosteroid use decreased significantly (P < 0.001) from baseline to weeks 10, 30, and 54 in children with moderate to severe Crohn disease. Comparing the REACH study (21) with our study, nearly 80% of the patients in the REACH study (21) had discontinued corticosteroids by week 14, whereas in our study, 40% of the patients had discontinued corticosteroids by week 22. It is possible that our attempt to taper or discontinue the corticosteroids was slower than that of the REACH study (21), but we believe that the high remission rate of our study was not due to continuation of corticosteroids. It is because, at time 0, the activity indices of IBD were high (PCDAI 31.9; LCAI 9.1; PUCAI 50.0; Harvey-Bradshaw Index 8.1) while patients were receiving corticosteroids. On the contrary, after 22 weeks of infliximab treatment, the activity indices decreased significantly (PCDAI 6.4; PCAI 0.7; PUCAI 5.0; Harvey-Bradshaw Index 1.0), as did the dose of corticosteroids. So, the continuation of corticosteroids could not be responsible of high rate remission.
We determined whether the patients' response to infliximab depends on the time in which the patient was diagnosed with IBD (early vs late onset), as published by Kugathasan et al (14). In the present study, there was no difference between the early and late groups during 22 weeks of trial. Kugathasan et al (14) observed no difference in the response of these groups during the first 10 weeks of their study, but they demonstrated that 50% of early disease–onset patients experienced clinical relapse, whereas 100% patients with long-standing disease experienced relapse in an open-label trial of a single infliximab intravenous infusion (5 mg/kg).
Infliximab induced a rapid response to therapy in children, although this group presented more severe disease compared with adolescents in the beginning of the present study.
It is important to emphasize that the majority of the previous trials that analyzed infliximab therapy in pediatric populations had low numbers of patients and analyzed infliximab for different periods of treatment. Therefore, our study is important because it reinforces that infliximab provides a beneficial role for treating children and adolescents with Crohn disease and ulcerative colitis.
In conclusion, the present study suggests that infliximab is effective in decreasing the activity indices of IBD, with a remarkable response documented for clinical manifestations and a reduction of corticosteroid levels, up to week 22. The follow-up of these patients must be considered with further studies to evaluate the long-term efficacy, safety, and tolerance of infliximab.
1. Knight DM, Trinh H, Le J, et al. Construction and initial characterization of a mouse-human chimeric anti-TNF antibody. Molec Immunol 1993; 30:1443–1453.
2. Derkx B, Taminiau J, Radema S, et al. Tumor-necrosis-factor-antibody treatment in Crohn's disease. Lancet 1993; 342:173–174.
3. Targan SR, Hanauer SB, van Deventer SJH, et al. A short-term study of chimeric monoclonal antibody cA2 to tumor necrosis factor α for Crohn's disease. N Engl J Med 1997; 337:1029–1035.
4. Present DH, Rutgeerts P, Targan S, et al. Infliximab for the treatment of fistulas in patients with Crohn's disease. N Engl J Med 1999; 340:1398–1405.
5. Cohen RD, Tsang JF, Hanauer SB. Infliximab in Crohn's disease: first anniversary clinical experience. Am J Gastroenterol 2000; 95:3469–3477.
6. Hanauer SB, Feagan BG, Lichtenstein GR, et al, ACCENT I Study Group. Maintenance infliximab for Crohn's disease: the accent I randomized trial. Lancet 2002; 359:1541–1549.
7. D'Haens G, van Deventer S, Hogezand RV, et al. Endoscopic and histological healing with infliximab anti-tumor necrosis factor antibodies in Crohn's disease: a European multicenter trial. Gastroenterology 1999; 116:1029–1034.
8. van Dullemen HM, van Deventer SJH, Hommes DW, et al. Treatment of Crohn's disease with anti-tumor necrosis factor chimeric monoclonal antibody (cA2). Gastroenterology 1995; 109:129–135.
9. Chey WY, Hussain A, Ryan C, et al. Infliximab for refractory ulcerative colitis. Am J Gastroenterol 2001; 96:2373–2381.
10. Su C, Zalzberg BA, Lewis JD, et al. Efficacy of anti-tumor necrosis factor therapy in patients with ulcerative colitis. Am J Gastroenterol 2002; 97:2577–2584.
11. Järnerot G, Hertervig E, Friis-Liby I, et al. Infliximab as rescue therapy in severe to moderately severe ulcerative colitis: a randomized, placebo-controlled study. Gastroenterology 2005; 128:1805–1811.
12. Rutgeerts P, Sandborn WJ, Feagan BG, et al. Infliximab for induction and maintenance therapy for ulcerative colitis. N Engl J Med 2005; 353:2462–2476.
13. Hyams JS, Markowitz J, Wyllie R. Use of infliximab in the treatment of Crohn's disease in children and adolescents. J Pediatr 2000; 137:192–196.
14. Kugathasan S, Werlin SL, Martinez A, et al. Prolonged duration of response to infliximab in early but not late pediatric Crohn's disease. Am J Gastroenterol 2000; 95:3189–3194.
15. Baldassano R, Braegger CP, Escher JC, et al. Infliximab (Remicade) therapy in the treatment of pediatric Crohn's disease. Am J Gastroenterol 2003; 98:833–838.
16. Borrelli O, Bascietto C, Viola F, et al. Infliximab heals intestinal inflammatory lesions and restores growth in children with Crohn's disease. Dig Liver Dis 2004; 36:342–347.
17. Lionetti P, Bronzini F, Salvestrini C, et al. Response to infliximab is related to disease duration in paediatric Crohn's disease. Aliment Pharmacol Ther 2003; 18:425–431.
18. de Ridder L, Escher JC, Bouquet J, et al. Infliximab therapy in 30 patients with refractory pediatric Crohn disease with and without fistulas in the Netherlands. J Pediatr Gastroenterol Nutr 2004; 39:46–52.
19. Cezard J-P, Nouaili N, Talbotec C, et al. A prospective study of efficacy and tolerance of a chimeric antibody to tumor necrosis factor (remicade) in severe pediatric Crohn disease. J Pediatr Gastroenterol Nutr 2003; 36:632–636.
20. Lamireau T, Cézard J-P, Dabalie A, et al. Efficacy and tolerance of infliximab in children and adolescents with Crohn's disease. Inflamm Bowel Dis 2004; 10:745–750.
21. Hyams J, Crandall W, Kugathasan S, et al, REACH Study Group. Induction and maintenance infliximab therapy for the treatment of moderate-to-severe Crohn's disease in children. Gastroenterology 2007; 132:863–873.
22. Serrano MS, Schmidt-Sommerfeld E, Kilbaugh TJ, et al. Use of infliximab in pediatric patients with inflammatory bowel disease. Ann Pharmacother 2001; 35:823–828.
23. Wewer V, Riis L, Husby S, et al. Infliximab dependency in a national cohort of children with Crohn's disease. J Pediatr Gastroenterol Nutr 2006; 42:40–45.
24. Eidelwein AP, Cuffari C, Abadom V, et al. Infliximab efficacy in pediatric ulcerative colitis. Inflamm Bowel Dis 2005; 11:213–218.
25. Mamula P, Markowitz JE, Brown KA, et al. Infliximab as a novel therapy for pediatric ulcerative colitis. J Pediatr Gastroenterol Nutr 2002; 34:307–311.
26. Mamula P, Markowitz JM, Cohen LJ, et al. Infliximab in pediatric ulcerative colitis: two-year follow-up. J Pediatr Gastroenterol Nutr 2004; 38:298–301.
27. Russel GH, Katz AJ. Infliximab is effective in acute but not chronic childhood ulcerative colitis. J Pediatr Gastroenterol Nutr 2004; 39:166–170.
28. de Ridder L, Benninga MA, Taminiau JA, et al. Infliximab use in children and adolescents with inflammatory bowel disease. J Pediatr Gastroenterol Nutr 2007; 45:3–14.
29. Kinney T, Rawlins M, Kozarek R, et al. Immunomodulators and “on demand” therapy with infliximab in Crohn's disease: clinical experience with 400 infusions. Am J Gastroenterol 2003; 98:608–612.
30. Hyams JS, Ferry GD, Mandel FS, et al. Development and validation of a pediatric Crohn's disease activity index. J Pediatr Gastroenterol Nutr 1991; 12:439–447.
31. Lichtiger S, Present DH, Kornbluth A, et al. Cyclosporine in severe ulcerative colitis refractory to steroid therapy. N Engl J Med 1994; 330:1841–1845.
32. Turner D, Otley AR, Mack D, et al. Development, validation, and evaluation of a pediatric ulcerative colitis activity index: a prospective multicenter study. Gastroenterology 2007; 133:423–432.
33. Harvey RF, Bradshaw JM. A simple index of Crohn's-disease activity. Lancet 1980; 1:514.
34. Zaltman C. Inflammatory bowel disease: how relevant for Brazil? Cad Saude Publica 2007; 23:992–993.
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