Phenotypic analysis of circulating T-cell subset and its association with burden of skin disease in patients with chronic actinic dermatitis: a hematologic and clinicopathologic study of 20 subjects

HIV-associated photodermatitis in African populations

Photosensitive dermatoses are seen in 5% of HIV-infected persons. These include drug- and chemical-induced photoallergic and phototoxic reactions, chronic actinic dermatitis of HIV, photo lichenoid drug eruptions, and porphyria. Data on photodermatitis in HIV are limited to case reports and series. The pathogenesis is not completely understood and includes a th2 phenotype in HIV which results in impaired barrier function and resultant allergen sensitisation as well as immune dysregulation. The objective of this manuscript is to review the literature on the clinical phenotype, pathogenesis, role of photo and patch testing, outcomes, and treatment of photodermatitis in HIV in an African population.

HIV-Associated Immune Dysregulation in the Skin: A Crucible for Exaggerated Inflammation and Hypersensitivity

Skin diseases are hallmarks of progressive HIV-related immunosuppression, with severe noninfectious inflammatory and hypersensitivity conditions as common as opportunistic infections. Conditions such as papular pruritic eruption are AIDS defining, whereas delayed immune-mediated adverse reactions, mostly cutaneous, occur up to 100-fold more during HIV infection. The skin, constantly in contact with the external environment, has a complex immunity. A dense, tightly junctioned barrier with basal keratinocytes and epidermal Langerhans cells with antimicrobial, innate-activating, and antigen-presenting functions form the frontline. Resident dermal dendritic, mast, macrophage, and innate lymphoid cells play pivotal roles in directing and polarizing appropriate adaptive immune responses and directing effector immune cell trafficking. Sustained viral replication leads to progressive declines in CD4 T cells, whereas Langerhans and dermal dendritic cells serve as viral reservoirs and points of first viral contact in the mucosa. Cutaneous cytokine responses and diminished lymphoid populations create a crucible for exaggerated inflammation and hypersensitivity. However, beyond histopathological description, these manifestations are poorly characterized. This review details normal skin immunology, changes associated with progressive HIV-related immunosuppression, and the characteristic conditions of immune dysregulation increased with HIV. We highlight the main research gaps and several novel tissue-directed strategies to define mechanisms that will provide targeted approaches to prevention or treatment.

Up-regulation of hsa-miR-221-3p induced by UVB affects proliferation and apoptosis of keratinocytes via Bcl-xL/Bax pathway

BACKGROUND

Chronic actinic dermatitis (CAD) is a photoallergic skin disease with abnormal hyperplasia. At present, the mechanism of abnormal proliferation is not clear.

OBJECTIVE

To explore possible mechanism of CAD proliferative lesions.

METHODS

Immunohistochemistry (IHC) assay and small RNA sequencing were carried out. Quantitative real-time PCR (qRT-PCR) analysis was performed to evaluate expression levels of hsa-miR-221-3p and FOS. The interaction between hsa-miR-221-3p and FOS was identified by dual-luciferase reporter assay. Expression of hsa-miR-221-3p also was detected by qRT-PCR after UVB irradiation. Influences of hsa-miR-221-3p and FOS on cell viability and apoptosis were assessed through a series of functional experiments and rescue experiments. Western blot analysis was used to detect protein expression of fos, Bax, Bcl-xL, and caspase-3.

RESULTS

Patients with CAD had marked epidermal hyperplasia. The expression of hsa-miR-221-3p was up-regulated in CAD while FOS was significantly down-regulated. Dual-luciferase reporter assay confirmed that hsa-miR-221-3p targeted FOS 3'UTR. Hsa-miR-221-3p induced by UVB ranged from 0 to 30 mJ. Moreover, hsa-miR-221-3p overexpression or FOS knockdown promoted cell proliferation and reduced cell apoptosis. Western blot showed that hsa-miR-221-3p negatively regulated fos, which regulated Bcl-xL/Bax. Cell proliferation caused by hsa-miR-221-3p overexpression or FOS knockdown could be reversed by Bcl-xL inhibitor.

CONCLUSION

Hsa-miR-221-3p induced by UVB targeted FOS 3'UTR, which played an important role in regulating proliferation and apoptosis of keratinocytes via Bcl-xL/Bax pathway; this may provide a new insight for CAD proliferative lesions.

Clinical and pathological findings of chronic actinic dermatitis

BACKGROUND

Chronic actinic dermatitis (CAD) is a recurrent photosensitive disease occurs predominantly in elderly men on sun-exposed areas, which seriously affect the patient's life quality. The etiology of CAD remains unknown.

METHODS

Sixty-six CAD patients, 66 atopic dermatitis (AD) patients, and 46 healthy people were enrolled into this study. Patient-level data were obtained from the electronic medical record and laboratory databases. We also obtained 29 tissue samples including 16 lichenoid lesions, 7 minimal erythematous dose (MED) analysis induced lesions, and 6 normal skin samples. Histopathologic and immunohistochemical analysis were performed.

RESULTS

In the clinical characteristics, albumin was lower and uric acid was higher significantly in patients diagnosed as CAD. The infection rate of CAD patient after skin biopsy was considerably high (23.3%). The serum allergen test was prone to be negative in CAD patients. Lymphocytes were the dominate infiltrating cells in early and late CAD lesions, while more CD4+, CD8+, CD69+, and CD103 + cells were found in the late lesions. There is no difference in CD4+/CD8 + ratio and CD69+/CD103 + ratio among groups. More mast cells were observed in the early-stage lesions, and more dendritic cell was observed in the late-stage lesions.

CONCLUSIONS

CAD patients have certain oxidative stress and are prone to be infected after skin biopsy. Serum allergen detection is of little significance for CAD diagnosis. Mast cells may be involved in the early process of CAD, while dendritic cells and tissue-resident memory T cell (TRM) may be related to the chronic process of the disease.

Mogamulizumab-induced photosensitivity in patients with mycosis fungoides and other T-cell neoplasms

BACKGROUND

Mogamulizumab (Mog) is a defucosylated, therapeutic monoclonal antibody, targeting CCR4 and was first approved in Japan for the treatment of adult T-cell leukaemia/lymphoma (ATLL), followed by cutaneous T-cell lymphoma and peripheral T-cell lymphoma.

OBJECTIVE

To retrospectively investigate development of photosensitivity in patients with mycosis fungoides and other T-cell neoplasms after treatment with Mog.

METHODS

We treated seven cutaneous lymphoma patients with Mog. Upon combination treatment with narrow-band UVB, we noticed that four patients developed photosensitivity dermatitis following Mog therapy, including two cases of mycosis fungoides, one case of adult T-cell leukaemia/lymphoma and one case of EB virus-associated T-cell lymphoproliferative disorder. Phototest was performed with UVA and UVB, and immunohistochemical staining for CD4, CD8 and Foxp3 was conducted in both photosensitivity and lymphoma lesions.

RESULTS

Phototest revealed that the action spectrum of the photosensitivity was UVB in three cases and both UVB and UVA in one case. Histopathologically, the photosensitive lesions were characterized by a lichenoid tissue reaction with a CD8⁺ T cell-dominant infiltrate, sharing the feature with chronic actinic dermatitis, an autoreactive photodermatosis with a cytotoxic T-cell response. Foxp3⁺ regulatory T cells (Tregs) were decreased in the photosensitivity lesions compared with the lymphoma lesions.

CONCLUSION

Increased incidence of photosensitivity reaction was observed during Mog treatment. Decreased number of Tregs in the lesional skin suggests that this reaction is possibly induced by autoreactive cytotoxic T cells.