Bullous pemphigoid blisters of the same duration have similar cytokine concentrations which decrease in older blisters

Proinflammatory Cytokine Gene Polymorphisms in Bullous Pemphigoid

Bullous pemphigoid (BP) is a rare autoimmune skin blistering disease, characterized by the presence of autoantibodies against hemidesmosomal autoantigens. Cytokine expression is altered in BP patients, and several of these differently expressed cytokines, including IL-1α, IL-1β, IL-8, and TNF-α, contribute to disease pathogenesis. Since genetic polymorphisms in the genes of these cytokines might be implicated in susceptibility to BP disease, we aimed at testing this implication in susceptibility to BP in an Iranian cohort. Blood samples were collected from the subjects and genomic DNA was extracted. To detect the single nucleotide polymorphisms (SNPs), IL-1α (rs1800587), IL-1β (rs1143627, rs16944, rs1143634), IL-8 (rs4073), and TNF-α (rs1799964, rs1800630, rs1799724, and rs361525) genes were genotyped in BP patients and healthy controls as well as IL-8 (rs4073) in pemphigus vulgaris (PV) patients. Quantitative gene expression was evaluated by RT-PCR analysis. A significant difference was observed in the distribution of genotypes or alleles of IL-8 SNP between the BP patients and controls. The A-allele of IL-8 SNP is significantly more prevalent in the control individuals compared to the BP patient. To further validate this observation, we included PV patients as an additional control. Again, the A-allele of IL-8 SNP is significantly more prevalent in the PV compared to the BP patients. While we observed a trend toward significant differences regarding alleles of TNF-α rs1799724 as well as alleles of TNF-α rs1799964, this difference was, however, not evident after correction for multiple analysis. There was no significant difference in all other studied SNPs. In contrast to IL-1α, IL-1β, and TNF-α, IL-8 gene expression levels were significantly higher in the patients than that of controls. The minor allele in IL-8 SNP might play a protective role in susceptibility to BP in Iranian patients. Although higher expression levels of IL-8 gene was found in the patients compared with healthy controls, these levels, however, suggest no association with the examined polymorphism. Moreover, further investigation revealed an elevation in gene expression between wild and polymorphic genotypes of IL-1α rs1800587 and TNF-α rs361525 in the patient group and these SNPs are therefore associated with altering the levels of gene expression.

Immunohistological analysis of immune cells in blistering skin lesions

BACKGROUND

Bullous skin lesions are characterised by the presence of intraepidermal or subepidermal bullae. Although inflammatory cell infiltrate is a constant feature in these lesions, their immunophenotypic characterisation is still incomplete.

AIM

To determine whether the development of bullous skin diseases is associated with changes in the inflammatory cell infiltrate.

MATERIALS AND METHODS

34 cases representing lesions with both intraepidermal and subepidermal bullae were examined using immunoperoxidase staining methods and antibodies targeting antigens for histiocytes (CD68), B cells (CD20+), T cells (CD3+), T cells with cytotoxic potential (T cell intracellular associated antigen, TIA1+) and activity (granzyme B, GRB+). The adjacent normal skin (lesions) and an additional five cases of normal skin were also examined (controls).

RESULTS

The transition from normal skin to lesional skin (lesions with intraepidermal and subepidermal bullae) was associated with a significant increase (p< or =0.05) in the density of total inflammatory cell infiltrate, CD68+ cells, CD3+ T lymphocytes, CD20+ B lymphocytes, TIA1+ -resting cytotoxic T cells and GRB+ T cells with cytotoxic activity.

CONCLUSIONS

The increase in inflammatory cell infiltrate during the transition from normal to lesional skin may reflect the presence of an increased antigenicity of the lesional cells or a response to some basement membrane components. CD68+ and CD3+ cells, especially the resting cytotoxic ones, achieved numerical dominance in these lesions. Cell-mediated immunity seems to have critical role in the development of these lesions.

Th1, Th2 and Th3 cytokines in the pathogenesis of bullous pemphigoid

Bullous pemphigoid (BP) is an autoimmune bullous skin disease mediated by autoantibodies against hemidesmosomal proteins. In addition to humoral immunity, the contribute of infiltrating T-helper (Th) autoreactive lymphocytes and their related cytokines to the pathomechanism of blistering is now growing in interest. To investigate T-cell activation markers and the presence of inflammatory and fibrogenic cytokines (i.e. IL2, IL-4, IL-5, IFN-gamma, TGF-beta) in BP lesional skin, we performed an immunohistochemical study and an in situ hybridization procedure on five BP patients, comparing them with two psoriatic patients and four healthy subjects. Our aim was to expand suitable information about tissutal expression of cytokines, secondly to further investigate the role of TGF-beta (a Th3-like or T-regulatory (T-reg) cytokine) in a non-scarring disorder like BP, in order to highlight its pleiotropic activity. The immunohistochemical analysis revealed a moderate to strong staining for IL-4 and IL-5 with a prevalent perivascular localization in the upper dermis. The staining for IFN-gamma showed a moderate/focal expression on the dermal perivascular infiltrate. IL-2 protein was observed in four cases. While no positive staining for IL-4 mRNA was detected in all BP subjects with in situ hybridization, IL-5 mRNA was documented in four BP specimens. A focal nuclear staining for IFN-gamma was observed in the epidermal layers and on the cellular infiltrate of lesional skin. In all BP cases, a moderate/diffuse positivity for TGF-beta(1) mRNA was documented in both cytoplasm and nucleus of the infiltrating perivascular cells of lesional and perilesional skin. Our results suggest a balance between Th1, Th2 and Th3 activity, with quantitatively different impact of the various cytokines on the pathomechanism of blistering, depending on the reciprocal network. The supposed participation of each cytokine analyzed in the pathogenesis of BP is discussed. The newest data obtained consist of TGF-beta detection in a non-scarring disease like PB, that had never been documented before, and in the confirmation of a mixed cytokine pattern in the fully developed phase of the disease.

Increased interleukin 10, tumor necrosis factor alpha, and interleukin 6 levels in blister fluid of toxic epidermal necrolysis

BACKGROUND

Toxic epidermal necrolysis is a severe, usually drug-induced disease that shares clinical, histologic, and immunologic similarities with the severe forms of cutaneous acute graft-versus-host disease.

OBJECTIVE

Our purpose was to further characterize common immune-inflammatory pathways in these skin disorders by measurement of different cytokines.

METHODS

Evaluation of serum levels of interleukin 10 (IL-10), tumor necrosis factor alpha, IL-6, and soluble IL-6 receptor in the early phase of both diseases and in blister fluid of toxic epidermal necrolysis.

RESULTS

Serum levels of IL-10 and IL-6 were significantly higher in patients with toxic epidermal necrolysis (P =.0001) and acute graft-versus-host disease (P =.001) compared with those of blood donors. We found an increase in IL-6 levels in blister fluid and significantly higher levels of IL-10 (P =.018) and tumor necrosis factor alpha (P =.028) in blister fluid compared with serum in patients with toxic epidermal necrolysis.

CONCLUSION

A similar serum cytokine profile of toxic epidermal necrolysis and acute graft-versus-host disease further emphasizes common immunologic mechanisms. The presence of inflammatory cytokines, IL-6 and tumor necrosis factor alpha, in the blister fluid of patients with toxic epidermal necrolysis is associated with significantly higher levels of IL-10, which through its down-regulatory role, may be involved in limitation of the disease extension.