Antinuclear and antinative DNA antibodies during captopril treatment

Enhancement of anti-OVA IgG2c production in vivo by enalapril

Angiotensin-converting enzyme (ACE) inhibitors have non-hemodynamic, pleiotropic effects on the immune response. The effects of ACE inhibitors on the production of cytokines and T-cell functions are well established. However, little is known on the effects of these medicines on humoral response to foreign antigens. In this study, we investigated the effect of enalapril treatment on ovalbumin (OVA)-specific IgG1 and IgG2c production in mice determined by ELISA. Two groups of 8-week-old C57BL/6 females mice (3-4/group) were subcutaneously immunized with OVA (10 μg/animal) in presence of Alhydrogel (1 mg/mouse) and boosted at day 21. The mice were treated with enalapril (5 mg/kg daily, po) or were left without treatment for one month. The animals were bled from the orbital plexus on days 0, 7, 14, 21, and 28 after the first immunization and the sera were stored at -20°C until usage. OVA-specific serum IgG1 and IgG2c were determined by ELISA using serum from each individual animal. The results showed that enalapril significantly increased anti-OVA serum IgG2c in the secondary response without affecting IgG1 synthesis. These data expand our understanding on the properties of enalapril on the immune response, including antibody production.

Angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers and the risk of developing rheumatoid arthritis in antihypertensive drug users

PURPOSE

Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) are effective in the treatment of cardiovascular disease. Next to effects on hypertension and cardiac function, these drugs have anti-inflammatory and immunomodulating properties which may either facilitate or protect against the development of autoimmunity, potentially resulting in autoimmune diseases. Therefore, we determined in the current study the association between ACE inhibitor and ARB use and incident rheumatoid arthritis (RA).

METHODS

A matched case-control study was conducted among patients treated with antihypertensive drugs using the Netherlands Information Network of General Practice (LINH) database in 2001-2006. Cases were patients with a first-time diagnosis of RA. Each case was matched to five controls for age, sex, and index date, which was selected 1 year before the first diagnosis of RA. ACE inhibitor and ARB exposure was considered to be any prescription issued in the period before index date. Logistic regression analysis was used to estimate odds ratios (ORs) and their 95% confidence intervals (CI).

RESULTS

Our study included 211 cases and 667 matched controls. After controlling for potential confounders, ever use of ACE inhibitors or ARBs was not associated with incident RA (adjusted ORs [95%CI], 0.99 [0.55-1.79] and 1.02 [0.67-1.56], respectively). The adjusted ORs (95%CI) for current and past use of ACE inhibitors were 1.18 (0.75-1.85) and 0.61 (0.28-1.35). For current and past use of ARBs, these adjusted ORs (95%CI) were 1.40 (0.80-2.45) and 0.29 (0.05-1.67), respectively. No duration and dose-effect relationship was observed.

CONCLUSIONS

ACE inhibitor or ARB use is not associated with incident RA.

Granulocytopenia after combined therapy with interferon and angiotensin-converting enzyme inhibitors: evidence for a synergistic hematologic toxicity

PURPOSE

The purpose of this study was to assess whether granulocytopenia observed in 3 of 38 patients with essential mixed cryoglobulinemia who were treated with low-dose interferon was due to the underlying disease or to synergistic toxicity of interferon with other drugs.

PATIENTS AND METHODS

Adverse effects of interferon therapy were monitored in 38 patients affected with type II essential mixed cryoglobulinemia. Patients were treated with 3 million units (MU), daily or on alternate days, of recombinant interferon-alpha 2a (35 patients) or with natural interferon-beta (3 patients). The duration of treatment ranged between 6 and 15 months; the total duration of follow-up, including after therapy, ranged between 8 and 93 months.

RESULTS

None of 35 patients treated with interferon alone developed significant hematologic alterations. In addition, none of 7 patients treated with angiotensin-converting enzyme (ACE) inhibitors alone showed hematologic toxicity. Three patients who were treated with a combination of interferon and ACE inhibitors developed severe granulocytopenia a few days after starting treatment. Granulocytopenia subsided within 1 to 2 weeks after suspending therapy. Resumption of treatment with this drug combination produced a granulocytopenia relapse in 1 patient. In these 3 patients, interferon treatment alone, or ACE inhibitor monotherapy, was not followed by granulocytopenia.

CONCLUSION

Although severe hematologic toxicity rarely develops in patients treated with low-dose interferon, granulocytopenia occurred in all 3 of our patients with mixed cryoglobulinemia who were treated with a combination of low-dose interferon-alpha 2a and ACE inhibitors. Neither drug alone was toxic in any of our cryoglobulinemic patients, indicating a high risk of severe hematologic toxicity for this drug combination, at least in patients with this disease. Physicians should be aware of this danger when using interferon treatment in patients with this, or possibly other, disorder(s) that also require antihypertensive therapy.

Silicone-reactive disorder: a new autoimmune disease caused by immunostimulation and superantigens

Over 100 cases of disorders closely resembling classic autoimmune diseases have been reported among patients who were injected or implanted with a diverse group of chemicals including paraffins, vegetable oils or silicone. Most cases have occurred in silicone breast implant recipients, especially those who received their prostheses 2-10 years prior to onset of symptoms. A high proportion of patients exhibit classic signs and symptoms of Sjogren's syndrome or scleroderma. Affected patients typically experience some combination of fatigue, myalgia, joint pain, sicca syndrome (dry eyes and mouth), synovitis, rash, alopecia, muscular weakness or lymphadenopathy, and autoantibody formation. Less commonly, patients may have the CREST syndrome (calcinosis, Raynaud's phenomena, esophageal hypomotility, sclerodactyly and telangiectasias), hypertension, pulmonary fibrosis, or central nervous system pathology.

Effect of inhibition of glutathione synthesis on the immunogenicity of captopril and captopril-protein conjugates in the mouse

The effect of glutathione (GSH) depletion on the immunogenicity of captopril (CP) and D-penicillamine (PA) was investigated in C57 mouse. Depletion of GSH was by DL-buthionine sulfoximine (BSO), a potent and specific inhibitor of GSH synthesis, injected on the days of immunization of the drug/drug-protein conjugates. Chronic BSO pretreatment for 5 consecutive days, before and including the 4-day immunization period, caused tissue GSH depletion (liver 60%, kidney 71%, lung 14%, spleen 14% and whole blood 36%) in C57 mouse. After chronic administration of CP (270 mumol/kg, i.p. or i.m.) or CP-HSA (200 micrograms, i.p. or i.m.), IgG antibody response to CP-derived antigen was detected by an enzyme-linked immunosorbent assay (ELISA). The IgG antibody recognised CP-OVA but not OVA, and was inhibited by CP in other protein conjugated form, thus confirming its specificity to CP. Depletion of GSH by BSO caused an increase in the CP-specific IgG antibody titre when CP/CP-HSA was immunized through i.p. (with or without Freund's Complete Adjuvant) but not i.m. administration. In contrast, chronic administration of PA (270 mumol/kg, i.p.) or PA-HSA (200 micrograms, i.p.), with or without BSO pre-treatment, did not lead to detectable PA-specific IgG antibody. The results again illustrate the difference in the intrinsic immunogenicity between CP and PA, in that depletion of GSH increased the humoral (B lymphocyte) anti-CP responses but not anti-PA responses under the experimental conditions. These findings suggest that GSH status, apart from its effects on the disposition of CP/CP-protein conjugates, should be considered as an important determinant of both the immunological and toxicological response to CP.

Angiotensin converting enzyme inhibitors. Properties and side effects

The purpose of this brief review is to separate the characteristic properties and side effects attributable to the pharmacology of the whole class of angiotensin converting enzyme (ACE) inhibitors from those attributable to the chemical structure and kinetics of each particular ACE inhibitor. The former would be predictable and probably similar for all agents and, therefore, would be expected to recur with each agent, whereas the latter are likely to be characteristic of individual compounds and may be avoidable by changing to another compound with similar pharmacology but different molecular structure.