Evidence for cell-mediated autoimmunity in patients with pemphigus vulgaris and bullous pemphigoid

Summary Lymphoid cells from 4 of 5 patients diagnosed as pemphigus vulgaris (PV) and 6 of 7 patients diagnosed as bullous pemphigoid (BP) demonstrated specific cell-mediated immunity by the production of migration inhibitory factor (MIF) in the presence of autologous epidermal saline extracts. Clinical treatment of these patients with immunosuppressive agents resulted in a state of unresponsivenes of their lymphoid cells to similar concentrations of the antigen. Controls consisted of lymphoid cells from patients with bullous burns or various drug allergies which failed to show significant MIF production in the presence of autologous skin extract. These studies suggest that both PV and BP patients posses cell-mediated immunity (CMI) to their own autologous tissue antigens and this CMI may play a role in the pathogenesis of these diseases.     

寻常型天疱疮与细胞免疫关系的研究进展

天疱疮是一种以体液免疫介导的自身免疫性疾病,但随着免疫学和分子生物学技术的发展,体内和体外研究均发现天疱疮发病中同时存在细胞和体液免疫紊乱,自身反应性T细胞在其发病中起着重要作用。近几年研究重点已逐渐转向细胞免疫在天疱疮发病中的作用,但细胞免疫及细胞因子在天疱疮发病机制中的综合作用迄今还有待进一步阐明。该文从细胞因子的角度对细胞免疫与天疱疮的关系作一综述。     

Comparative pathology of pemphigus in dogs and humans

To dermatologists who have little knowledge of veterinary dermatology, it may come as a surprise that autoimmune skin diseases occur in species other than humans. In actuality, many of the same immune-mediated vesiculopustular and collagen vascular diseases identified in humans have been described in animals. These include bullous pemphigoid, dermatomyositis, erythema multiforme, variants of lupus erythematosus, immune-mediated vasculitis, and a number of the pemphigus diseases.^1–3     

Evidence for altered cell-mediated immunity in postmastectomy lymphoedema

Patients with chronic lymphoedema are prone to develop chronic infections and various tumours in the lymphoedematous limb, suggesting that regional immune surveillance is impaired. To test the hypothesis that cutaneous cell-mediated immunity is impaired. 35 women with postmastectomy lymphoedema were investigated using dinitrochlorobenzene to test the afferent and efferent loops of the allergic contact immune response. The results suppot the role of lymphatics as an important component of the immune response to allergens by the demonstration of impairment of both the afferent and efferent loops of the allergic contact dermatitis reaction, and confirm that there is suppression of immune competence in a lymphoedematous limb.     

Autoreactive T cells in the immune pathogenesis of pemphigus vulgaris

Pemphigus vulgaris is a life‐threatening autoimmune blistering disease caused by anti‐desmoglein IgG autoantibodies that finally lead to acantholysis presenting clinically as progressive blistering. Whilst the production of pathogenic antibodies is key to the development of pemphigus vulgaris, many immunological steps are required prior to autoantibody induction. We review advances in the understanding of these immunologic processes with a focus on human leucocyte antigen polymorphisms and antigen recognition, epitope spreading, central and peripheral tolerance, T helper differentiation, induction of pro‐ and anti‐inflammatory cytokines and T‐cell regulation of B cells. Targeting autoaggressive T cells as regulators and stimulators of B‐cell antibody production should allow for more specific therapeutic immune interventions, avoiding the global immunosuppression seen with many commonly used immunosuppressants in pemphigus vulgaris.     

Deregulation of PERK in the autoimmune disease pemphigus vulgaris occurs via IgG-independent mechanisms

Background Serum and IgG isolated from patients with the autoimmune blistering disease pemphigus vulgaris (PV) trigger complex intracellular pathways in keratinocytes, including alterations of the cell cycle and metabolism, which ultimately lead to cell–cell detachment (acantholysis). We have shown previously that one of the earliest pathogenic events in PV is the activation of protein kinases, including the PKR‐like endoplasmic reticulum (ER) kinase PERK. Objectives In the present study we investigated in more detail the role of PERK in the pathogenesis of PV. Methods PERK levels were assessed by Western blotting and in‐cell enzyme‐linked immunosorbent assay, and PERK expression was silenced by siRNA technology. The effects of PV sera/IgG on keratinocyte cultures were investigated by flow cytometry, MTT and adhesion assays. Results We show that PERK is activated in keratinocytes exposed to PV serum, as demonstrated by an increase in phosphorylated PERK levels and phosphorylation of eIF2α. Decreased expression of PERK by siRNA reduced the effects of PV serum on the cell cycle and keratinocyte viability, two key events in PV pathophysiology. As impairment of metabolic activity in PV is partially due to non‐IgG serum factors, we then investigated the activation of PERK in keratinocytes incubated with whole PV serum, purified PV IgG and IgG‐depleted PV serum. The data demonstrated that PV sera depleted of IgG, but not PV IgG, triggered PERK phosphorylation and this correlated with a marked reduction of metabolic activity in keratinocytes exposed to IgG‐free serum. Knockdown of PERK by siRNA abrogated the changes in the cell cycle and apoptosis induced by IgG‐depleted PV serum. Finally, the reduction of metabolic activity observed in keratinocytes exposed to IgG‐depleted PV serum was almost absent in PERK‐deficient cells. Conclusions Taken together, the results demonstrate that activation of PERK participates in the reduction of metabolic activity and cell viability seen in PV and that this phenomenon depends on non‐IgG factors. PERK activation may represent a novel signalling mechanism linking ER stress and acantholysis in PV.     

Involvement of immune mechanisms in the pathogenesis of rosacea

Twenty-five patients with rosacea were compared with twenty-five control subjects for previous medical history and tests of immune function. Rosacea patients were found to have a higher incidence of disorders of the auto-immune type and were significantly more difficult to sensitize to DNCB than the controls. In addition, twelve of the rosacea patients and eleven other rosacea patients had biopsies which were examined by the direct immunofluorescence technique. In only five was the test negative. In the remainder deposits of IgM and/or IgG and/or complement were found at the dermo-epidermal junction and/or in the dermal collagen. Serum from the rosacea patients was also examined by the indirect technique and in six cases a circulating antinuclear antibody of IgM type was found. It is suggested that altered immune function plays a significant role in the pathogenesis of the disease.     

A prospective study on clinical response and cell-mediated immunity of pemphigus patients treated with rituximab

Rituximab has recently been reported in retrospective studies to be effective in pemphigus at the dosing schedule used for treating rheumatoid arthritis (RA) of two 1,000 mg infusions 2 weeks apart. While the effect of rituximab on B cells has been well described, its effect on global T cell function has not been assessed. Ten patients who received RA dosage rituximab were prospectively assessed for clinical response. Immunological response including autoantibody titers, CD20+ B cell, and CD4+ T cell counts was assessed pre- and post-treatment. The CD4+ T cell function was determined by a novel assay measuring intracellular ATP levels in response to mitogenic stimulus. At 6 months, 90 % of patients achieved remission. Disease control and remission were achieved at median times of 1 and 3.7 months, respectively. There was a 67 % relapse rate during an average follow-up of 22 months. Global CD4+ T cell numbers and function were preserved 3 months after rituximab. A single cycle of RA dosage rituximab with concomitant immunosuppression is effective in pemphigus. We did not find an effect on total CD4+ T cell numbers or function 3 months after treatment.     

Role of cell-mediated immune reaction in blister formation of bullous pemphigoid.

In patients with bullous pemphigoid (BP), early lesions appear as exudative erythematous patches. Histologically, the inflammatory infiltrate is composed mainly of mononuclear cells (MNCs) in the erythematous lesion, although eosinophils and neutrophils are also present. The MNCs are predominantly helper/inducer T cells even in the bullous lesions. Some of the MNCs infiltrated were stained in cytoplasm by antihuman gamma-interferon (IFN-gamma) monoclonal antibody (MoAb) immunohistologically. These infiltrates are considered to produce IFN-gamma. In the bullous fluids of early BP lesions, high levels of IFN-gamma are detected by radioimmunoassay using antihuman IFN-gamma MoAb. The results suggest that infiltrating lymphocytes are stimulated immunologically in BP bullous lesions. Cell-mediated immune reaction as well as autoantibody to the basement membrane zone may also play an important role in blister formation in BP.     

Evidence of an association between desmoglein 3 haplotypes and pemphigus vulgaris

BACKGROUND: Pemphigus vulgaris (PV, OMIM 169610) is a severe blistering disorder of the skin and mucous membranes, caused by the production of autoantibodies directed against the epithelial adhesive protein desmoglein 3. Although an association between PV and HLA class II alleles has been established, the genetic factors predisposing to the disease remain poorly understood, the rarity of PV hampering the recruitment of substantial patient cohorts. OBJECTIVES: To investigate DSG3 as a candidate PV susceptibility gene. METHODS: We examined five DSG3 single nucleotide polymorphisms (rs8085532, rs3911655, rs3848485, rs3794925 and rs1466379) in two case-control datasets respectively originating from the U.K. (62 PV patients, 154 controls) and northern India (28 patients, 98 controls). RESULTS: In the U.K. sample, we observed a significant association between PV and the DSG3*TCCTC haplotype (Fisher's exact test P = 0.002). A related haplotype (DSG3*TCCCC) was associated with PV in the Indian dataset (P = 0.002). We also found that all British and Indian patients bearing DSG3 risk haplotypes carried at least one copy of a PV-associated HLA allele. CONCLUSIONS: These results suggest that genetic variation of DSG3 may be an additive risk factor predisposing to PV and warrant further investigations of this gene.     

利妥昔单抗在天疱疮的应用

天疱疮是一种严重的自身免疫性大疱病,部分病例对传统治疗的疗效不佳.近几年临床研究发现,利妥昔单抗可明显提高天疱疮患者的临床治愈率,且可获得长期缓解,复发后再次治疗的安全性与临床缓解率仍较理想.利妥昔单抗不仅适用于重症难治性天疱疮,也有治疗轻至中度甚至儿童天疱疮的相关报道.目前已有较多关于利妥昔单抗不同单次治疗剂量或总剂量使天疱疮病情缓解的报道.利妥昔单抗可联合用药提高临床缓解率,其在安全剂量内仍会出现相关不良反应.     

B-cell depletion immunotherapy in pemphigus: effects on cellular and humoral immune responses

Pemphigus are B-cell-mediated autoimmune diseases affecting skin and mucous membranes. They are characterized by the production of pathogenic autoantibodies directed against desmogleins (Dsg). In this prospective study, we treated 21 pemphigus patients with rituximab and analyzed immunological modifications induced by anti-CD20 immunotherapy. The total depletion of peripheral B cells led to a significant decrease of total serum IgM but not IgG levels. The B-cell depletion was followed by a progressive re-emergence of naive blood B lymphocytes, with one-third of them expressing a transitional CD19+CD38(high)CD24(high) phenotype. In most patients, clinical response to rituximab was closely related to the evolution of anti-Dsg autoantibodies that decreased in patients who achieved complete remission, whereas they remained unchanged or reincreased in relapsing patients. In contrast, serum antimicrobial IgG remained stable after rituximab treatment. B-cell repertoire analysis of three patients using immunoscope showed distortions of VH-IgM and VH-IgG immunoscope profiles before treatment, particularly clonal and oligoclonal expansions in some VH families, which were not found after B-cell reconstitution, following anti-CD20 immunotherapy. The depletion of autoreactive B cells leading to the elimination of anti-Dsg autoantibodies in most remitted patients and the restoration of a diverse B-cell repertoire by naive B lymphocytes may provide an explanation for the long-lasting efficacy of rituximab in pemphigus patients.     

Cyclosporin A in the treatment of pemphigus foliaceus and pemphigus erythematosus

We present the cases of two female patients with pemphigus foliaceus and pemphigus erythematosus, respectively, who did not respond to long-term azathioprine and prednisone treatment in high dosages. In both patients the skin condition improved nearly completely after therapy with cyclosporine A (3.5-6.5 mg/kg per day) in combination with prednisone (7.5-10 mg every 2 days). We did not observe any side-effects during 1 year of this therapy.