Treatment of rheumatoid arthritis with immunosuppressive drugs. II. Immunological study

Thiopurine Monotherapy Is Effective in Maintenance of Mild-Moderate Inflammatory Bowel Disease

BACKGROUND

Crohn's disease (CD) and ulcerative colitis (UC) are complex, inflammatory bowel diseases (IBD) with debilitating complications. While severe IBD typically requires biologic agents, the optimal therapy for mild-moderate IBD is less clear.

AIMS

To assess the efficacy of thiopurine monotherapy for maintenance of mild-moderate IBD and clinical variables associated with treatment outcome.

METHODS

This retrospective study included adults with mild-moderate IBD who were started on thiopurines without biologic therapy. The primary outcome was therapy failure, defined by disease progression based on clinical, endoscopic, and radiologic criteria. Clinical variables were extracted at time of thiopurine initiation. Univariable and multivariable Cox proportional hazards models were used to examine the independent contribution of the clinical variables on treatment response.

RESULTS

From 230 CD patients, 64 (72%) were free of treatment failure with mean follow-up of 3.3 years. In our multivariable model, thiopurine failure was associated with concomitant systemic steroid administration (aHR 2.43, p = 0.001), whereas protective factors included concomitant oral 5-aminosalicylic acid (5-ASA) therapy (aHR 0.54, p = 0.02) and non-fistulizing, non-stricturing disease (aHR 0.57, p = 0.047). From 173 UC patients, 50 (71%) were free from treatment failure with mean follow-up of 3.3 years. On multivariable analysis, concomitant oral steroids were associated with thiopurine failure (aHR 2.71, p = 0.001). Only 13 (4%) discontinued thiopurines from adverse effects.

CONCLUSIONS

In mild-moderate uncomplicated IBD, thiopurine monotherapy was associated with longitudinal maintenance of remission and may represent a lower-cost, convenient, and effective alternative to biologics. Multiple clinical variables were predictive of treatment response.

Immunosuppressive therapy of idiopathic thrombocytopenic purpura

The autoimmune nature of idiopathic thrombocytopenic purpura, as currently defined, is well established. Manipulations of the immune apparatus aimed at abating this deviant immunologic state may be one mode of approach to the therapy of this disease. Several cytotoxic compounds are capable of inhibiting the primary and secondary immune response to experimentally injected antigens in animals and man. Their beneficial role in the treatment of an autoimmune lupus-like syndrome in NZB mice24 is well documented. In human autoimmune disease, efficacy of the drugs is still to be established. The mechanisms by which immunosuppressive agents effect therapeutic response, and, in particular, whether this action is linked to suppression of immune reactivity needs clarification. Although preliminary analysis of the efficacy of immunosuppressive drugs in idiopathic thrombocytopenic purpura is encouraging, their therapeutic role has not superseded that of conventional management with steroids and splenectomy. Carefully controlled randomized clinical trials are now necessary so that more rational use of these agents can be recommended in future reports.

The effect of azathioprine on gammaglobulin synthesis in man

The effect of azathioprine therapy on gammaglobulin synthesis was evaluated in nine patients with rheumatic disorders. The rates of synthesis of IgG and IgM were calculated before and after 4 months of azathioprine treatment using turnover studies of radioiodinated gammaglobulins. The synthesis of IgG decreased 33.4% of the initial IgG synthetic rate. Seven of nine patients showed reductions of IgG synthesis ranging from 16.8 to 74.1%. IgM production decreased from 24.5 to 74.2% in eight of nine patients with a mean reduction of 40.9%. Studies before and after a control period of 4 months of placebo in six patients revealed a mean increase in IgG and IgM synthesis. Serum immunoglobulin concentrations after 4 months of azathioprine treatment were not consistently reduced and did not parallel changes in immunoglobulin synthesis. Reduced gammaglobulin synthesis may play a role in the therapeutic action of this and other "immunosuppressive" drugs.

Azathioprine in rheumatoid arthritis

The ability of azathioprine to reduce the corticosteroid requirements of patients with severe rheumatoid arthritis was tested under double-blind conditions against placebo. After 12 months a significant mean dose reduction of 36% was achieved without undue side-effects. This form of therapy promises to be an advance in the management of severe rheumatoid arthritis.