Age-associated decrease of CD1d protein production in normal human skin

Developmentally programmed early-age skin localization of iNKT cells supports local tissue development and homeostasis

Skin is exposed to various environmental assaults and undergoes morphological changes immediately after birth. Proper localization and function of immune cells in the skin is crucial for protection and establishment of skin tissue homeostasis. Here we report the discovery of a developmentally programmed process that directs preferential localization of invariant natural killer T (iNKT) cells to the skin for early local homeostatic regulation. We show that iNKT cells are programmed predominantly with a CCR10+ skin-homing phenotype during thymic development in infant and young mice. Early skin localization of iNKT cells is critical for proper commensal bacterial colonization and tissue development. Mechanistically, skin iNKT cells provide a local source of transferrin that regulates iron metabolism in hair follicle progenitor cells and helps hair follicle development. These findings provide molecular insights into the establishment and physiological functions of iNKT cells in the skin during early life.

Age-associated decrease in GDNF and its cognate receptor GFRα-1 protein expression in human skin

Glial cell line-derived neurotrophic factor (GDNF) and its cognate receptor (GFRα-1) are expressed in normal human skin. They are involved in murine hair follicle morphogenesis and cycling control. We hypothesize that 'GDNF and GFRα-1 protein expression in human skin undergoes age-associated alterations. To test our hypothesis, the expression of these proteins was examined in human skin specimens obtained from 30 healthy individuals representing three age groups: children (5-18 years), adults (19-60 years) and the elderly (61-81 years). Immunofluorescent and light microscopic immunohistologic analyses were performed using tyramide signal amplification and avidin-biotin complex staining methods respectively. GDNF mRNA expression was examined by RT-PCR analysis. GDNF mRNA and protein as well as GFRα-1 protein expressions were detected in normal human skin. We found significantly reduced epidermal expression of these proteins with ageing. In the epidermis, the expression was strong in the skin of children and declined gradually with ageing, being moderate in adults and weak in the elderly. In children and adults, the expression of both GDNF and GFRα-1 proteins was strongest in the stratum basale and decreased gradually towards the surface layers where it was completely absent in the stratum corneum. In the elderly, GDNF and GFRα-1 protein expression was confined to the stratum basale. In the dermis, both GDNF and GFRα-1 proteins had strong expressions in the fibroblasts, sweat glands, sebaceous glands, hair follicles and blood vessels regardless of the age. Thus there is a decrease in epidermal GDNF and GFRα-1 protein expression in normal human skin with ageing. Our findings suggest that the consequences of this is that GFRα-1-mediated signalling is altered during the ageing process. The clinical and therapeutic ramifications of these observations mandate further investigations.

Expression of cytokeratin 10 protein in the human testis showing normal and abnormal spermatogenesis

BACKGROUND

CK10 is a heterotetramer of type I and two type II keratins.

AIM

This study examines the expression pattern of cytokeratin 10 (CK10) in human testis.

MATERIALS AND METHODS

CK10 protein expression was examined using immunofluorescense staining methods in 30 human testicular biopsy specimens (normal spermatogenesis, maturation arrest and Sertoli cell only syndrome, 10 cases each) obtained from patients undergoing investigations for infertility.

RESULTS

In the testis showing normal spermatogenesis, CK10 was expressed in the interstitium and in the seminiferous tubules. A strong cytoplasmic expression was seen in the Leydig cells, Sertoli cells, and spermatocytes. In testes showing spermatogenic arrest, weak CK10 protein expression was observed both in the interstitium and seminiferous tubules (some primary spermatocytes). In the testes showing Sertoli cell only syndrome, negligible CK10 staining was seen both in the seminiferous tubules and in the interstitial cells of Leydig.

CONCLUSIONS

To the authors' knowledge, this is the first study indicating CK10 expression in the human testis during normal and abnormal spermatogenesis. The varied expression of CK10 in testes showing abnormal spermatogenesis suggests its possible involvement in this process.

Skin-limited Langerhans' cell histiocytosis in children

Langerhans' cells are dendritic cells derived from precursors in the bone marrow. They constitute 2-4% of the resident epidermal cells and are found within the epidermis above the basal layer. They function as immunologic cells by recognizing antigens and presenting them to T cell lymphocytes. Langerhans' cell histiocytosis is a rare pathology characterized by an abnormal clonal proliferation of Langerhans' cells that infiltrates different organs of the human body. The proliferating Langerhans' cells appears to be primarily responsible for the clinical manifestations. The stimulus for their proliferation is unknown. Among different organs, cutaneous involvement is encountered in 40% of cases. The aim of this investigation is to review the clinicopathologic, immunologic and ultrastructural features of skin-confined Langerhans' cell histiocytosis in children through seven case series. Four boys and two girls with age range of 1 year to 8 years presented with scaling, crusted papules, nodules and papulonodular lesions (two cases each). The locations included the face (three cases), scalp, trunk and vulva (one case each). The histological features included histiocytic reaction (one case), granulomatous reactions (three cases) and both granulomatous and histiocytic reactions (two cases). The diagnosis was confirmed by histochemical (S-100 + CD1a +) and ultrastructural studies (Birbeck granules). Langerhans' cell histiocytosis is a rare disease with pleomorphic cutaneous clinical expressions. Three types of skin lesions usually occur: nodules (common), scaling, or crusted papules (next in frequency) and finally soft, yellow papular xanthomas (rare). Three types of histological pictures are seen: histiocytic, granulomatous (common) and xanthomatous (rare).

Evaluation of the profile of the immune cell infiltrate in lichen planus, discoid lupus erythematosus, and chronic dermatitis

AIMS

The term 'interface dermatitis' refers to those dermatoses in which an inflammatory process involves the dermoepidermal junction, with injury and even necrosis of the basal cell keratinocytes. Interface dermatitis can be characterised further as being either vacuolar or lichenoid changes. Immune cell infiltrate is a constant feature in interface dermatitis. In this study, we hypothesised that 'the profile of the immune cell infiltrate varies between lichenoid and vacuolar interface dermatitis'. This investigation tries to test this hypothesis and to characterise immune cells in interface dermatitis.

METHODS

Thirty-one interface dermatitis lesions (interface dermatitis group: 19 cases of lichen planus, LP; and 12 cases of discoid lupus erythematosus, DLE) and 20 specimens of normal skin (control group) were examined using immunoperoxidase staining methods. Antibodies targeting histiocytes/dendritic cells (CD68+), T cells (CD3+), B cells (CD20+), T cells with either cytotoxic potential (TIA-1+) or cytotoxic activity (Granzyme-B+) were used to decorate the immune cells. In addition, 16 cases of chronic dermatitis [lichen simplex chronicus (LSC), non-interface dermatitis group] were included to substantiate findings in the interface dermatitis group. The results were scored as mean values of positively stained immune cells.

RESULTS

The numbers of immune cells were significantly high (p < 0.05) in the lesional skin (LP, DLE and LSC) compared with normal skin. The most prevalent cell populations were CD3+ T lymphocytes followed by CD68+ cells. Most of the CD3+ cells were resting (TIA-1+, cytotoxic potential) rather than active T cells (Granzyme-B+, active cytotoxicity). Numeric variations were seen between interface and chronic dermatitis groups with significant increase of the density of immune cells in the interface dermatitis (p < 0.05). We found some variations in the composition and distribution of immune cell infiltrate between LP (lichenoid change) and DLE (vacuolar changes). The mean counts of CD3+ cells were high in LP compared with DLE (p < 0.05). Alternatively, the density of CD20+ cells was high in DLE compared with LP (p < 0.05). High density of CD3+ (perivascular location and dermoepidermal junction, p < 0.05) positively stained cells was found in LP compared with DLE. In contrast, high density of CD20+ (perivascular location and dermoepidermal junction, p < 0.05), TIA-1+ and Granzyme-B+ (perivascular location and dermoepidermal junction, p > 0.05) positively stained cells was observed in DLE compared with LP.

CONCLUSIONS

Here we report some variations in the profile (density and positioning) of the immune cell infiltrate between LP and DLE. These variations include high density of CD68+ cells and CD3+ T lymphocytes in LP and DLE; and the numeric dominance of CD20+ B-lymphocytes in DLE compared with LP. Also, some differences in the density of TIA-1+ and Granzyme-B+ cytotoxic T cells between LP and DLE were observed. Our findings suggest a possible link between the type of these cells and the development of interface dermatitis lesions. The possible ramifications of these findings are open for further investigations.