Dietary gluten challenge does not influence the levels of circulating immune complexes in patients with dermatitis herpetiformis

Fc receptor function and circulating immune complexes in gluten sensitive enteropathy--possible significance of serum IgA

The capacity to clear IgG containing immune complexes from the circulation was studied in patients with coeliac disease (n = 13), dermatitis herpetiformis (n = 8), and coeliac disease with concomitant serum IgA deficiency (n = 4). A small group of patients with active ulcerative colitis (n = 4) was included as a bowel disease control group. Clearance was estimated by measuring the disappearance rate of a bolus dose of intravenously injected IgG coated autologous erythrocytes. The mean T1/2 of clearance was prolonged in both coeliac disease (86 (24) minutes) and dermatitis herpetiformis (111 (35) minutes), compared with healthy subjects (20 (5) minutes) and coeliac patients with concomitant serum IgA deficiency (T1/2 = 17 (6) minutes). Patients with ulcerative colitis had a prolonged clearance, with a T1/2 of 195 (63) minutes. Values of circulating immune complexes were measured by four assays; C1q binding and C3, IgG, and IgA containing immune complexes. C1q binding immune complexes were detected only in IgA deficient gluten sensitive enteropathy. Patients with coeliac disease and dermatitis herpetiformis had higher values of C3, IgG, and IgA containing immune complexes than control subjects and serum IgA deficient patients with coeliac disease. The clearance rate was inversely correlated to the amount of immune complexes for the subgroups of gluten sensitive enteropathy.

The pathogenesis of dermatitis herpetiformis: recent advances

Over the last two decades a rapid expansion of our knowledge regarding dermatitis herpetiformis has occurred, including the discovery of IgA in the skin, the discovery of an associated gluten-sensitive enteropathy, the noting of an increased prevalence of the human lymphocyte antigens (HLA)-B8 and -DRw3, and the documentation that the skin disease of many dermatitis herpetiformis patients can be controlled by a gluten-free diet. It has also been noted that two distinct forms of dermatitis herpetiformis occur, those with granular deposits of IgA at the dermoepidermal junction (85%-95% of dermatitis herpetiformis patients) and those with linear IgA deposits (10%-15% of dermatitis herpetiformis patients). These findings are reviewed with particular emphasis on the form of dermatitis herpetiformis associated with granular IgA deposits. The current findings regarding the nature and origin of the cutaneous IgA deposits, the role of the gluten-sensitive enteropathy, and the spectrum of both the immunologic and the nonimmunologic abnormalities associated with dermatitis herpetiformis are presented, and from these data pathophysiologic mechanisms are proposed that may be involved in dermatitis herpetiformis.

Effectiveness of cyclosporin therapy for Behçet's disease

Behcet's disease is a clinical entity with mouth and genital ulcers, skin lesions, and both anterior and posterior uveitis as its major criteria. It has been theorized that Behcet's disease is immune complex mediated, and is characterized by multiple attacks which often lead to severe visual handicap. Behcet's disease patients with severe ocular involvement and cytotoxic and/or systemic corticosteroid agent failures were treated with cyclosporin (CsA). CsA therapy effectively abrogated the acute phase of the ocular attack and either totally prevented, or markedly reduced, the recurrences of these attacks. Generally, patients tolerated the medication well; occasionally however, renal toxicity secondary to cyclosporin therapy prevented prescription of a maximally effective therapeutic dose of the drug. CsA levels in plasma were dose-dependent for each patient, but the dosage per kg of CsA needed to obtain a specific plasma level varied greatly from patient to patient. Circulating immune complex levels were not universally elevated during the acute ocular attack. However, increases in circulating immune complex concentrations were noted after treatment with CsA was begun and the disease became clinically inactive. These data, as well as the effectiveness of CsA, an agent with predominantly anti-T cell effects, raise a question as to whether circulating immune complexes are centrally relevant to the pathogenesis of this disorder, and if T cell mediation of this disease must be contemplated.

Circulating immune complexes: their immunochemistry, biology, and detection in selected dermatologic and systemic diseases

Circulating immune complexes (CICs) are a heterogeneous group of immunoreactants formed by the noncovalent union of antigen and antibody. Many factors influence the formation, immunochemistry, biology, and clearance of these soluble reactants. The recent development of sensitive assays for the detection of CICs and the capability to assess immune complex (IC) clearance mechanisms in humans in vivo have expanded our understanding of these mediators. CICs influence both the afferent and efferent limbs of the immune response and can mediate tissue damage in certain pathologic states. ICs probably play an important role in the pathogenesis of serum sickness, systemic lupus erythematosus, and cutaneous necrotizing vasculitis. Recent investigations have raised the possibility that CICs may be of significance in other types of vasculitis as well. In other instances, ICs may form in response to tissue injury and subsequently modify the immune response of the host. A review of this material with special emphasis on diseases of relevance to dermatologists is presented.