Increased expression of the natural killer cell inhibitory receptor CD94/NKG2A and CD158b on circulating and lesional T cells in patients with chronic plaque psoriasis

BACKGROUND

Psoriasis is a common inflammatory cutaneous disorder characterized by activated T-cell infiltration. T lymphocytes bearing natural killer cell receptors (NKRs) have been suggested to play an important role in the pathogenesis of psoriasis. However, the expression pattern of activating and inhibitory NKRs on T lymphocytes from psoriatic patients and its significance in psoriasis needs further study.

OBJECTIVES

To investigate the pathogenesis of NKR-expressing T cells in psoriasis.

MATERIALS AND METHODS

Thirty patients with chronic plaque psoriasis and 20 healthy controls were enrolled in this study. The immunophenotypic profiles of NKRs, including CD56, CD16 (activating NKRs), CD158a, CD158b, CD94 and NKG2A (inhibitory NKRs), were analysed in peripheral blood T lymphocytes, as well as psoriatic lesional infiltrating T cells, by triple-fluorescence flow cytometry.

RESULTS

A significant increase of inhibitory CD8+ CD158b+, CD4 CD8 CD158b+ and CD8+ CD94/NKG2A+ T cells was found in the peripheral blood of patients with psoriasis when compared with controls. Tissue-infiltrating T lymphocytes expressing inhibitory receptors CD158b, CD94 and NKG2A were found in psoriatic lesions. There was a significant positive correlation between the increased percentage of circulating CD8+ CD94/NKG2A+ T cells and the Psoriasis Area and Severity Index.

CONCLUSIONS

In the present study, we demonstrated increased proportions of particular subsets of inhibitory CD158b+ and/or CD94/NKG2A+ T cells in patients with psoriasis. The elevation of these inhibitory NKR-expressing T cells was correlated with disease severity, which may signify the possibility of chronic antigen-driven stimulation and dysregulated cytokine production in the pathogenesis of psoriasis.

Pattern of skin diseases in a geriatric patient group in Taiwan: a 7-year survey from the outpatient clinic of a university medical center

BACKGROUND

Geriatric health care has become a worldwide concern, but relatively few statistical studies are available about geriatric skin diseases. Moreover, no information exists regarding skin disorders among the elderly population in Taiwan that has become a geriatric country.

OBJECTIVE

To determine the characteristic pattern and the prevalence of various skin disorders for the elderly who visited the National Taiwan University in the last 7 years.

METHODS

Using a database from the Dermatology Outpatient Clinic of the National Taiwan University Hospital, 1993-1999 file, we conducted a retrospective cross-sectional study by evaluating the age, proportion, and gender of each specific cutaneous disease category, chi(2) tests were used for analyzing statistical significance. The analysis supplied odds ratios and 95% confidence intervals.

RESULTS

A total of 16,924 patients aged 65 years and older, which constituted 11% of the total patients seen at the Clinic of Dermatology from 1993 through 1999, were studied. The male to female ratio was 1.3 to 1. The most common cutaneous disorder in the elderly was dermatitis (58.7%), followed by fungal infections (38.0%), pruritus (14.2%), benign tumors (12.8%), and viral infections (12.3%). Cutaneous malignant tumors were found in 2.1%. Basal cell carcinoma occurred in 29.8%, actinic keratosis in 22.4%, Bowen's disease in 13.3% and squamous cell carcinoma 13.3%. Interestingly, our cases of extramammary Paget's disease showed a male predominance. Most melanomas were acral lentiginous melanoma located on the soles. The prevalence of common diseases in elderly patients compared with those outpatients of less than 65 years showed a 3-fold increased risk for pruritus. Moreover, the pattern of geriatric skin diseases in Taiwan was significantly different from Western countries.

CONCLUSION

The prevalence of skin diseases in elderly patients emphasizes the importance of health education in geriatric people in Taiwan concerning appropriate use of emollients, proper foot care, sun protection and early detection of skin cancers.