Linear IgA bullous dermatosis: a retrospective study of 23 patients in Denmark

Linear IgA bullous dermatosis (LAD) is an autoimmune, chronic bullous disease affecting primarily young children and adults. Studies on LAD are relatively sparse and from Scandinavia we could only find a few case reports. Therefore we decided to conduct a retrospective investigation of patients seen at our department since 1972. A total of 23 patients were identified; 7 children (F:M ratio 0.75) and 16 adults (F:M ratio 0.78). Mean age at disease onset in the two age groups were 2.7 and 56.8 years. Estimated incidence rate in our region: 0.67 per million per year. The most commonly used treatment modalities were corticosteroids, dapsone and sulphapyridine.

Immunosuppressive therapy for ocular mucous membrane pemphigoid strategies and outcomes

PURPOSE

To evaluate the effectiveness and toxicity of a stepladder immunosuppression strategy, including the use of mycophenolate mofetil and combination therapy, in the treatment of ocular mucous membrane pemphigoid.

DESIGN

Retrospective, noncomparative, interventional case series.

PARTICIPANTS

Two hundred twenty-three eyes of 115 patients.

METHODS

Patients with a diagnosis of ocular mucous membrane pemphigoid commencing immunosuppression between January 1994 and July 2005 were identified. A treatment episode was defined by the use of a particular therapy or combination of therapies.

MAIN OUTCOME MEASURES

For each treatment episode, success of immunosuppressive therapy in controlling ocular inflammation was graded as a success (S), qualified success (QS), or failure (F). Initial and final visual acuities (VAs), stage of cicatrization (Foster, Mondino), grade of conjunctival inflammation, and side effects were recorded.

RESULTS

In 70% (80/115) of patients, inflammation was controlled by the end of the study. At least 6 months remission off treatment occurred in 16 patients (14%). Of the 388 treatment episodes, 50% were classified as S; 27%, QS; and 23%, F. The most successful therapies were based on cyclophosphamide (S, 69%; QS, 21%; F, 10%), followed by mycophenolate (S, 59%; QS, 22%; F, 19%), azathioprine (S, 47%; QS, 24%; F, 29%), dapsone (S, 47%; QS, 30%; F, 23%), and sulfapyridine (S, 38%; QS, 27%; F, 35%). Combination sulfa-steroid-myelosuppressive agent therapy increased the response from 73% with single-agent therapy to 87%. Side effects were the reason for 29% of changes in therapy. These were most prominent with azathioprine (40%) and least with mycophenolate (15%). Initial best-corrected VA (BCVA) was 6/60 or less in 17% (37/223) of eyes, pemphigoid being the cause in 13% (29/223). Final BCVA was 6/60 or less in 34% (76/223) of eyes, pemphigoid being the cause in 26% (57/223). By the end of the study, Mondino stage cicatrization had progressed in 41% (92/223) of eyes and 53% (61/115) of patients.

CONCLUSIONS

Mycophenolate mofetil seems to be an effective and well-tolerated immunosuppressant for moderately active ocular mucous membrane pemphigoid. Combination sulfa-steroid-myelosuppressive agent therapy in a stepladder regimen is a useful strategy to improve disease control. Cicatrization and VA may still progress and worsen despite adequate control of inflammation.

Dapsone and sulfapyridine

Dapsone and sulfapyridine are structurally related compounds with anti-microbial and anti-inflammatory effects. Dapsone remains the most important drug for leprosy and is useful in the prophylaxis of Pneumocystis pneumonia in patients with HIV disease. The medical treatment of choice for dermatitis herpetiformis is dapsone; and sulfapyridine also can be used for those patients who are intolerant of dapsone. Other neutrophilic disorders also may respond to these drugs. Toxic side effects of both dapsone and sulfapyridine are mediated through the hydroxylamine metabolite. These include hemolysis, methemoglobinemia, and agranulocytosis. Careful monitoring for possible adverse reactions includes frequently performing complete blood counts and regular blood chemistry profile determinations.

Treatment with sulfasalazine or sulfapyridine, but not 5-aminosalicyclic acid, inhibits basic fibroblast growth factor-induced endothelial cell chemotaxis

OBJECTIVE

Rheumatoid arthritis (RA) is characterized by leukocyte recruitment and angiogenesis. We investigated the effects of sulfasalazine (SSZ) and its metabolites, sulfapyridine (SP) and 5-aminosalicylic acid (5-ASA), on components of angiogenesis, namely, endothelial cell (EC) chemotaxis and proliferation, as well as on EC chemokine and soluble adhesion molecule expression.

METHODS

SSZ, SP, and 5-ASA were assayed for their effects on basic fibroblast growth factor (bFGF)-induced human dermal microvascular endothelial cell (HMVEC) chemotaxis and proliferation. EC were plated on Matrigel to assess the effect of SSZ on EC tube formation. Enzyme-linked immunosorbent assays were performed to determine changes in HMVEC production of interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), growth-related oncogene alpha (GROalpha), epithelial neutrophil-activating peptide 78 (ENA-78), soluble E-selectin (sE-selectin), and soluble intercellular adhesion molecule 1 (sICAM-1) upon treatment with SSZ or its metabolites.

RESULTS

HMVEC incubated with SSZ or SP exhibited reduced bFGF-induced chemotaxis (59%, [n = 7] and 22%, [n = 3], respectively) (P<0.05). SSZ and SP decreased basal HMVEC proliferation, while 5-ASA increased proliferation (P<0.05; [n = 5]). SSZ decreased bFGF-induced HMVEC proliferation (P<0.05 [n = 5]). SSZ inhibited phorbol 12-myristate 13-acetate-induced HMVEC tube formation (P<0.05; [minimum n = 5]). Tumor necrosis factor alpha-stimulated HMVEC shedding of sICAM-1 was reduced by incubation with either SSZ (19%) or 5-ASA (23%) (P<0.05; [n = 6]). SP inhibited cytokine-stimulated HMVEC expression of IL-8 and MCP-1 (P<0.05; [n = 4]). Neither SSZ nor its metabolites had any effect on HMVEC production of sE-selectin, GROalpha, or ENA-78.

CONCLUSION

These results demonstrate that SSZ and its metabolite SP may affect the pathogenesis of RA by inhibiting EC chemotaxis, proliferation, tube formation, and expression of sICAM-1, IL-8, and MCP-1.

Linear IgA disease histopathologically and clinically masquerading as lichen planus

In each of 2 cases reported, the patient presented with features of erosive lichen planus or lichenoid drug eruptions and an incisional biopsy taken from the patient was diagnosed histologically as lichen planus. Subsequent recurrences or exacerbations were associated with vesiculobullous lesions. Simultaneous or subsequent direct immunofluorescence studies--from the same tissue sample in one case and from a similar site in the other case--demonstrated classic features of linear IgA disease. Both patients were originally treated for lichen planus with systemic and/or topical corticosteroids with limited success. One patient was treated with sulfapyridine with minimal improvement. Both patients were subsequently treated with dapsone and demonstrated significant clinical improvement. We propose that linear IgA disease may be more common than reported in the oral cavity, inasmuch as many cases of recalcitrant lichen planus, erosive lichen planus, and lichenoid drug eruptions, especially those with a vesiculobullous component, may in reality represent linear IgA disease. We recommend that direct immunofluorescence be done in any case in which bullous lichen planus is suspected.

[Ulcerative colitis and intestinal bleeding]

Ulcerative colitis is a nonspecific inflammatory disease of large intestine. Its inflammation is limited to intestinal mucosa. The most essential symptom is hematochezia, bloody stool and intestinal bleeding. Differential diagnosis among diseases having intestinal bleeding is clinically important. These diseases include Crohn disease, ischemic colitis, intestinal Behçet disease, Enterohemorrhagic E. coli including O157, antibiotics associated hemorrhagic colitis and so on. Drugs for the treatment of ulcerative colitis are sulphapyridine, 5-aminosalicylic acid, prednisolone, betamethasone and immunosuppressive drugs. Recently, leukocytapheresis and massive immunoglobulin 7S treatment are available for the treatment of ulcerative colitis.

The effect of sulphasalazine on neutrophil superoxide generation in rheumatoid arthritis

The production of superoxide by the peripheral blood neutrophils of 19 patients with active rheumatoid arthritis was measured during treatment with sulphasalazine (SASP). The response to drug treatment was determined by change in plasma viscosity, CRP, early morning stiffness and articular index over a 10-point scale. Of the 19 patients studied, eight were considered to have responded well to SASP and seven to have responded poorly or not at all. Over the treatment period, plateau levels of superoxide production fell in seven of the eight responders (P = 0.028) compared with a non-significant fall in 3/7 of the non-responder groups. The initial rate of superoxide production also fell in the responder group, but this was not statistically significant. Initial values in both the responder and non-responder groups were comparable with those seen for normal controls. Analysis of drug levels showed all patients to be compliant with drug treatment; however, drug levels and neutrophil activity were not correlated. Studies of the effect of SASP and sulphapyridine on superoxide production in vitro showed no difference between good and poor responders. These results suggest that there is no inherent difference between good and poor responders regarding the susceptibility of their neutrophils to SASP. SASP's action on neutrophils, therefore, appears not to be its main mechanism of disease-modifying activity in RA.

[Pharmacological studies of BX661A. 5-[4-(2-carboxyethylcarbamoyl)-phenylazo]-salicylic acid disodium salt dihydrate (1). Therapeutic effects on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) model in rats]

In the present study, we investigated the therapeutic effects of 7- or 14-day treatment with BX661A or salazosulfapyridine (SASP) in the DSS-induced UC model in rats. BX661A (10-300 mg/kg, p.o.) dose-dependently decreased the erosion area and the shortening of the large intestine. On the other hand, SASP (30 and 100.mg/kg, p.o.) dose-dependently decreased the erosion area in the treatment for 14 days (on the contrary, % inhibition of erosion area was reduced by the dose of 300 mg/kg), but did not improve the shortening of the large intestine. Secondly, we investigated the therapeutic effects of 5-aminosalicylic acid (5-ASA), 4-aminobenzoyl- beta-alanine (4-ABA) and sulfapyridine (SP) by intrarectal administration on the DSS-induced UC model in rats. 5-ASA significantly decreased the erosion area in the large intestine and improved the length of the large intestine of rats that was shortened by ingesting DSS. On the other hand, 4-ABA and SP improved neither the shortening nor the erosion area of the large intestine. These results suggest that BX661A may be clinically effective and useful in the treatment of patients with ulcerative colitis. Furthermore, it was suggested that 5-ASA may be the active moiety for the therapeutic effects of BX661A and SASP.

Sulphapyridine--a new agent for the treatment of ocular cicatricial pemphigoid

AIMS

Ocular cicatricial pemphigoid (OCP) is a severe, potentially sight threatening systemic disease that sometimes requires systemic immunosuppression. This study assessed the clinical outcome of patients with OCP treated with sulphapyridine, a sulphonamide with an anti-inflammatory and immunosuppressive action but few side effects.

METHODS

A prospective, single armed, unmasked clinical trial was undertaken at Moorfields Eye Hospital. Twenty consecutive patients with moderate or marked conjunctival inflammation due to OCP were treated with oral sulphapyridine 500 mg twice daily. The degree of ocular inflammation was assessed as nil, mild, moderate, marked, or severe. Success was defined as resolution to mild or less. Ocular limbitis, systemic features of the disease, and side effects of the drug were also monitored.

RESULTS

Follow up was a mean of 12.3 (SD 4.0) months and ranged from 7 to 17 months. A successful reduction in inflammation was recorded in 22/39 eyes (56%) and 10/20 patients (50%). This improvement occurred within 1 month in 64% and in all by 2 months. Three patients developed allergy. Other side effects included nausea (n = 3), headache (n = 1), urinary hesitancy (n = 1), and mild lymphocytopenia (n = 1). These were dose dependent. Progression of cicatrisation was observed in 1/22 eyes. Success was less likely if there were systemic features of OCP or ocular limbitis.

CONCLUSIONS

Sulphapyridine was clinically effective in 50% of patients with moderate marked inflammation and had few side effects. It is a good alternative to dapsone.

The antipruritic effects of chlorpheniramine, cyproheptadine and sulphapyridine monitored with limb activity meters on chloroquine induced pruritus among patients with malaria

Limb activity meters, otherwise modified self-winding watches that can record limb agitative movements such as in itch-provoked scratch, were introduced for an objective evaluation of the relative effectiveness of three antipruritic drugs: chlorpheniramine, cyproheptadine, and sulphapyridine for palliating pruritus associated with chloroquine chemosuppressive treatment of acute malarial febrile paroxysms in eighteen adult patients. Six fit and healthy subjects were also studied to obtain data for unmedicated controls. The meters were used to monitor the upper and lower limb activities of the patients during nocturnal sleep for 6 hours over 3 consecutive nights, after they had developed the chloroquine-induced pruritus and were then administered the antipruritic medications, six patients per drug, by a random selection. Sulphapyridine antipruritic treatment significantly reduced the activities of the upper limbs of itchy patients much greater than did cyproheptadine (P < 0.0001, right hand; P < 0.01 left hand). However sulphapyridine-treated patients still itched significantly more than controls from the greater activities in the dominant right hand of the patients (P < 0.05). Cyproheptadine had a marginally-better performance than chlorpheniramine, generally, in palliating the chloroquine-induced pruritus but only in one of 3 nights, for the right hand recordings, were the limb activities significantly different. There was no significant difference observed in the activities of the lower limbs for the unmedicated controls compared to itchy patients, irrespective of the antipruritic treatment mode. Five out of the 6 patients treated with sulphapyridine also complained of anorexia plus a feeling of fullness or indigestion.(ABSTRACT TRUNCATED AT 250 WORDS)

Linear IgA disease manifesting as recalcitrant desquamative gingivitis

A case of desquamative gingivitis caused by adult linear IgA disease is presented. Management initially proved to be difficult, however, the introduction of sulfapyridine caused rapid resolution of the gingival problem. This is one of the first reports of desquamative gingivitis caused by linear IgA disease successfully treated with sulfapyridine.

Childhood pemphigus foliaceus

We describe a girl who presented at the age of 12 years with a blistering eruption on the lower limbs. One week later, numerous new bullae and blisters were present. Skin biopsy for histology and immunofluorescent studies established the diagnosis of pemphigus foliaceus.

Three blistering diseases. Why proper management is critical

Dermatitis herpetiformis, pemphigus vulgaris, and bullous pemphigoid are uncommon, but not rare, blistering diseases. Accurate diagnosis is essential so that prognosis can be estimated and proper treatment begun. The systemic drugs used in treatment can cause major complications, and careful monitoring is vital. Management is best achieved with a team approach consisting of a primary care physician and a dermatologist.

Sulfapyridine and sulfones decrease glycosaminoglycans viscosity in dermatitis herpetiformis, ulcerative colitis, and pyoderma gangrenosum

Shortly after the introduction of sulfa drugs, sulfapyridine was found to have unique therapeutic properties, unrelated to antibacterial activity. Later, sulfones were found to share the same properties. The disorders initially improved were dermatitis herpetiformis, pyoderma gangrenosum, subcorneal pustular dermatosis, acrodermatitis continua, impetigo herpetiformis and ulcerative colitis. They were also sometimes helpful in many other disorders. They are effective in select disorders characterized by edema followed by granulocytic inflammation or edema followed by vesicle or bullae formation. The sulfones work in low doses in leprosy and their mode of action is not fully understood. Several pieces of experimental information are available. It is proposed that these drugs are entering or influencing the protein moiety of glycosaminoglycans and decreasing tissue viscosity. This decreased tissue viscosity prevents edema and dilution of tissue fluid and decreases acute inflammation and vesicle and bullae formation.

[Hypersensitivity pneumonia caused by sulfonamides]

A 59-year-old man with Duhring's disease (herpetiform dermatitis) developed undulating fever and pulmonary infiltrates soon after sulfapyridine treatment was started. When the drug was discontinued, a positive provocation test unequivocally established the diagnosis of hypersensitivity pneumonia. There was also a cross-reaction with sulfonyldianiline (dapsone). This case illustrates the need of considering a hypersensitivity reaction as the cause of fever and (or) pulmonary infiltration during sulphonamide administration.

Dapsone as first line therapy for bullous pemphigoid

In an open study, a total of 18 patients with proven bullous pemphigoid (16 new patients and two in relapse) were treated with a trial of dapsone (17 patients) or sulphonimide (one patient). Overall, eight patients were controlled on one of these agents as the sole treatment (44%). Six patients had a partial, but inadequate response, while four did not respond. The responses to the sulpha drugs were generally rapid, i.e. within 2 weeks, and the maximum doses used in any patient were 100 mg/day dapsone and 1.5 g/day of sulphapyridine or sulphamethoxypyridazine. Significant side-effects to dapsone occurred in six of the 17 patients. A trial of a sulphone or sulphonamide drug is warranted in bullous pemphigoid both as an initial treatment or in the treatment of relapse, particularly when there is a contraindication to the use of corticosteroids. Side-effects are common and therapy needs to be closely monitored.

Systemic lupus erythematosus presenting as a bullous eruption in a child

An 8-year-old girl presented with a generalized bullous eruption clinically resembling bullous pemphigoid or chronic bullous disease of childhood. Further study revealed immunopathologic findings seen in patients with epidermolysis bullosa acquisita or bullous systemic lupus erythematosus (SLE). Although she did not fulfill the American Rheumatism Association (Atlanta) criteria for SLE at her presentation, one year later she went on to do so. As well as being the youngest patient reported with bullous SLE, our patient is noteworthy because the bullous eruption was the initial manifestation of her SLE. Bullous SLE should be considered in the differential diagnosis of children presenting with generalized bullous eruptions.

Co-trimoxazole in rheumatoid arthritis: a comparison with sulphapyridine

The antirheumatoid activity of sulphasalazine and sulphapyridine may result from their antibacterial properties. The second line activity of sulphamethoxazole, in the form of cotrimoxazole (CTZ), has been investigated by treatment of 13 patients with RA for 24 weeks with CTZ (480 mg three times a day). The drug was found to be poorly tolerated, only five of the thirteen patients recruited completing the study. High circulating concentrations of sulphamethoxazole were found, with mean (SD) steady state serum concentrations reaching 54.02 (23.38) micrograms/ml. A significant reduction in serum IgM from 280 to 130 IU/l was observed, but otherwise disease activity remained unchanged or deteriorated throughout the course of the study. In contrast, patients with RA treated with sulphapyridine (1.25 g a day) showed improvement in disease activity. The results argue against an antibacterial mechanism of action for sulphasalazine and sulphapyridine in rheumatoid arthritis, unless this occurs at a site inaccessible to sulphamethoxazole.

A study to determine the active moiety of sulphasalazine in rheumatoid arthritis

Thirty patients with active rheumatoid arthritis (RA) participated in an open study of 6 months' treatment with either 5-aminosalicylic acid (5-ASA) or sulphapyridine (SP), the two moieties of sulphasalazine (SASP). Patients were assessed at regular intervals using clinical and biochemical tests designed to detect specific antirheumatic activity. Patients taking SP showed significant improvement in disease activity, but those taking 5-ASA did not improve, despite the fact that high serum concentrations of 5-ASA and acetyl 5-ASA were achieved. These results suggest that SP is the active moiety of SASP. Its possible mode of action is discussed. Nausea was a frequent problem in patients taking SP. Unless this can be overcome, SP is unlikely to offer any therapeutic advantages over SASP in the treatment of RA.

5-Aminosalicylic acid or sulphapyridine. Which is the active moiety of sulphasalazine in rheumatoid arthritis?

Thirty patients with active rheumatoid arthritis participated in an open study of 6 months' treatment with either 5-aminosalicylic acid or sulphapyridine, the two moieties of sulphasalazine. Patients were assessed at regular intervals using a number of clinical and biochemical tests designed to detect specific antirheumatic activity. Patients taking sulphasalazine showed significant improvement in most parameters of disease activity, but those taking 5-aminosalicylic acid did not improve despite the fact that high serum concentrations of 5-aminosalicylic acid and acetyl 5-aminosalicylic acid were achieved. These results suggest that sulphapyridine is the active moiety of sulphasalazine. Its possible mode of action is discussed. Nausea was a frequent problem in patients taking sulphapyridine. Unless this problem can be overcome, sulphapyridine is unlikely to offer any therapeutic advantages over sulphasalazine in the treatment of rheumatoid arthritis.

Malignant pyoderma

Malignant pyoderma is a destructive, ulcerating skin disease that occurs chiefly in young adults. Only eight cases of this rare disease have been reported. The head and neck have been involved in all cases, and a predilection for the periauricular region has been noted in several of the cases. Although the disease is progressive and chronic, responses to high-dose systemic corticosteroids have been noted, but usually a flare is associated with a reduction in dose. An additional case is described in which therapy with isotretinoin and sulfapyridine led to complete remission.

Which component of sulphasalazine is active in rheumatoid arthritis?

Sulphasalazine is known to be effective as a second line agent in the treatment of rheumatoid arthritis. The two chemical constituents of sulphasalazine (sulphapyridine and 5-aminosalicylic acid) were assessed separately in the treatment of rheumatoid arthritis. Over 24 weeks sulphapyridine showed a pronounced second line effect comparable with sulphasalazine and with a similar toxicity profile, whereas 5-aminosalicylic acid showed only a weak first line effect. Thus sulphapyridine appears to be the active moiety responsible for the second line effect of sulphasalazine in rheumatoid arthritis. The efficacy of the antibacterial component of sulphasalazine yet again permits speculation about the role of a bacterial pathogen in the aetiopathogenesis of rheumatoid disease.

The course of chronic bullous disease of childhood

We followed three children who met the clinical, histologic, and immunologic criteria for chronic bullous disease of childhood (linear IgA dermatosis). All patients were able to discontinue therapy after two months to two years. Two have continued to experience transient mild episodes of blistering that have not required reinstitution of systemic therapy. In our opinion, children with this condition have a benign course with disease-free remissions and can be expected to discontinue all therapy eventually.

Chronic bullous dermatosis of childhood

Chronic blistering dermatosis of childhood (CBDC) in a 1-year-old black girl responded to the administration of sulfapyridine. CBDC is a rare blistering skin disease characterized by the presence of tense bullae and the linear deposition of IgA at the dermal-epidermal junction of lesional and perilesional skin. The disease may resemble bullous impetigo, bullous erythema multiforme, dermatitis herpetiformis, or pemphigus. The treatment involves the use of either dapsone or sulfapyridine.

Chronic bullous dermatosis of childhood. Linear iga bullous dermatosis

A 21/2-year-old boy had large, tense bullae on the groin, buttocks, legs and abdomen. A subepidermal vesicle was seen on histological study. Immunofluorescent studies revealed linear IgA at the basement membrane zone. There was no associated gastrointestinal abnormality or any other systemic feature. The patient responded dramatically to sulfapyridine. He has had no recurrence of the disease and negative immunofluorescence study results during two years of follow-up.

Inflammatory bowel disease in childhood

In addition to proctocolectomy, new surgical techniques for treating ulcerative colitis include the Kock internal ileal reservoir and endorectal pullthrough of the ileum. In children three forms of Crohn's disease requiring operation have been identified. Ileocecal disease may be treated with resection and anastomosis; colorectal disease is best managed by primary proctocolectomy cutaneous ileostomy; and Crohn's disease of the small bowel should be managed by medical therapy in most cases.

Placental transfer of sulphasalazine and sulphapyridine and some of its metabolites

In eleven pregnant patients with ulcerative colitis or Crohn's disease who were treated with sulphasalazine (SASP) the serum concentrations of SASP and sulphapyridine (SP) were measured at delivery. The concentrations of SASP and SP were almost identical in the cord serum and the maternal serum. In seven of the women the same concentrations were measured at a later occasion when they were not pregnant. The serum SASP concentration remained the same, but the SP concentration was higher in the non-pregnant women. This probably reflects the different degree of protein binding of SASP and SP, respectively, and the change of distribution volume that occurs in pregnancy. In the newborn the concentrations of SASP and SP were 4.6 +/- 3.1 microgram/ml and 18.2 +/- 8.7 microgram/ml, respectively. Current studies have shown that neither SASP nor SP in these concentrations causes significant displacement of bilirubin from albumin. Thus, SASP can be given to the pregnant patient up to delivery without risks for the newborn full-term infant.

Therapeutic efficacy of sulfasalazine and its metabolites in patients with ulcerative colitis and Crohn's disease

We studied the therapeutic efficacy of sulfasalazine and its metabolites sulfapyridine and 5-aminosalicylic acid in nine patients with Crohn's disease and in 23 patients with ulcerative colitis. In a randomized, controlled trial, we treated 11 patients for six weeks with 1 g of sulfasalazine three times a day, seven patients with 0.5 g of sulfapyridine three times a day, and 14 patients with 0.5 g of 5-aminosalicylic acid suppositories three times a day. The clinical state of the disease was characterized by an activity index, quality of stool, and remission rate. In addition, we monitored plasma levels of sulfapyridine, 5-aminosalicylic acid, and their acetylated metabolites. The initial activity index (mean +/- S.D.) was significantly reduced by sulfasalazine (from 245 +/- 129 to 100 +/- 71; P < 0.001) and by 5-aminosalicylic acid (from 251 +/- 65 to 90 +/- 93; P < 0.0001), but sulfapyridine was without benefit. Stool quality was also improved by sulfasalazine (82 per cent of the cases) and by 5-aminosalicylic acid (79 per cent). The highest remission rate was achieved with 5-aminosalicylic acid (86 per cent), followed by sulfasalazine (64 per cent) and sulfapyridine (14 per cent). Our investigations show that 5-aminosalicylic acid is the active moiety of sulfasalazine and that this effective metabolite may be an alternative to sulfasalazine in inflammatory bowel disease.