An epidermotypic model of interface dermatitis reveals individual functions of fas ligand and gamma interferon in hypergranulosis, cytoid body formation, and gene expression

Acute graft-versus-host disease presenting as Stevens-Johnson syndrome and toxic epidermal necrolysis: A retrospective cohort study

BACKGROUND

Cutaneous manifestations resembling Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) have been reported in patients with acute graft-versus-host disease (aGVHD); however, the clinicopathological characteristics of SJS/TEN-like aGVHD remain unexplored.

OBJECTIVE

To investigate the clinicopathology, complications, and outcomes of patients with SJS/TEN-like aGVHD.

METHODS

We analyzed a multicenter cohort of patients with aGVHD between 2000 and 2021.

RESULTS

We analyzed 31 patients with aGVHD, including SJS/TEN-like (n = 15) and non-SJS/TEN-like (n = 16). Patients with SJS/TEN-like aGVHD had significantly more extensive erythema and skin detachment/mucositis. SJS/TEN-like aGVHD was significantly associated with higher aGVHD grading and systemic complications, including pancytopenia, leukopenia, anemia, severe thrombocytopenia, coagulation abnormality, hepatitis, diarrhea, renal dysfunction, and bacteremia. A significantly lower hemoglobin/red cell distribution width ratio was identified in SJS/TEN-like aGVHD. Histopathology showed significant severe dyskeratosis and interface change. Patients with SJS/TEN-like aGVHD had lower 2-month survival rates and 5.35-fold higher 5-year mortality rates than those with non-SJS/TEN-like aGVHD. Total mortality rates of patients with SJS/TEN-like aGVHD reached 80% during follow-up; sepsis predominated the causes of death.

LIMITATIONS

Retrospective, nonrandomized study with a small sample size.

CONCLUSION

SJS/TEN-like aGVHD is associated with multiple systemic complications and high mortality. Early recognition, differential diagnosis from drug-induced-SJS/TEN, and appropriate treatment are critical.

Immunostimulatory Endogenous Nucleic Acids Perpetuate Interface Dermatitis-Translation of Pathogenic Fundamentals Into an In Vitro Model

Interface dermatitis is a histopathological pattern mirroring a distinct cytotoxic immune response shared by a number of clinically diverse inflammatory skin diseases amongst which lichen planus and cutaneous lupus erythematosus are considered prototypic. Interface dermatitis is characterized by pronounced cytotoxic immune cell infiltration and necroptotic keratinocytes at the dermoepidermal junction. The initial inflammatory reaction is established by cytotoxic immune cells that express CXC chemokine receptor 3 and lesional keratinocytes that produce corresponding ligands, CXC motif ligands 9/10/11, recruiting the effector cells to the site of inflammation. During the resulting anti-epithelial attack, endogenous immune complexes and nucleic acids are released from perishing keratinocytes, which are then perceived by the innate immune system as danger signals. Keratinocytes express a distinct signature of pattern recognition receptors and binding of endogenous nucleic acid motifs to these receptors results in interferon-mediated immune responses and further enhancement of CXC chemokine receptor 3 ligand production. In this perspective article, we will discuss the role of innate nucleic acid sensing as a common mechanism in the perpetuation of clinically heterogeneous diseases featuring interface dermatitis based on own data and a review of the literature. Furthermore, we will introduce a keratinocyte-specific in vitro model of interface dermatitis as follows: Stimulation of human keratinocytes with endogenous nucleic acids alone and in combination with interferon gamma leads to pronounced production of distinct cytokines, which are essential in the pathogenesis of interface dermatitis. This experimental approach bears the capability to investigate potential therapeutics in this group of diseases with unmet medical need.

Immune response patterns in non-communicable inflammatory skin diseases

Non-communicable inflammatory skin diseases (ncISD) such as psoriasis or atopic eczema are a major cause of global disease burden. Due to their impact and complexity, ncISD represent a major challenge of modern medicine. Dermatology textbooks describe more than 100 different ncISD based on clinical phenotype and histological architecture. In the last decades, this historical description was complemented by increasing molecular knowledge - and this knowledge is now being translated into specific therapeutics. Combining the enormous advances made in lymphocyte immunology and molecular genetics with clinical and histological phenotyping reveals six immune response patterns of the skin - type I immune cells cause the lichenoid pattern characterized by immune-mediated cell death of keratinocytes; type II immune cells underlie the eczematous pattern with impaired epidermal barrier, infection and eosinophils as well as the bullous pattern with loss of epithelial integrity; Th17 cells and ILC3 mediate the psoriatic pattern characterized by acanthosis, high metabolic activity and neutrophils; dysbalance of regulatory T cells causes either the fibrogenic pattern with rarefication of cells and dermal thickening or the granulomatous pattern defined by formation of granulomas. With more and more specific therapeutic agents approved, classifying ncISD also according to their immune response pattern will become highly relevant. This review defines the six immune response patterns of ncISD and highlights therapeutic strategies targeting key lymphocyte mediators.