CD4(+)CD25(+)FoxP3(+) regulatory T cells are increased whilst CD3(+)CD4(-)CD8(-)alphabetaTCR(+) Double Negative T cells are decreased in the peripheral blood of patients with multiple myeloma which correlates with disease burden.

Increased levels of naturally occurring regulatory T cells (T(Reg) cells) have been found in a variety of solid tumours and haematological malignancies. In multiple myeloma (MM), evidence suggests that T(Reg) cells are increased though controversy exists with regards to their function and no relationship to disease stage and treatment has been demonstrated. Here, we demonstrate significantly elevated levels of functional CD4(+)CD25(+)FoxP3(+) T(Reg) cells in a large cohort of patients with MM as well as monoclonal gammopathy of uncertain significance (MGUS) in comparison to age-matched, healthy controls.

Presence of epidermal allantoin further supports oxidative stress in vitiligo.

Xanthine dehydrogenase/xanthine oxidase (XDH/XO) catalyses the hydroxylation of hypoxanthine to xanthine and finally to uric acid in purine degradation. These reactions generate H(2)O(2) yielding allantoin from uric acid when reactive oxygen species accumulates. The presence of XO in the human epidermis has not been shown so far.

A novel mechanism in control of human pigmentation by {beta}-melanocyte-stimulating hormone and 7-tetrahydrobiopterin.

The human skin holds the full machinery for pro-opiomelanocortin processing. The alpha-melanocyte-stimulating hormone (alpha-MSH)/melanocortin-1-receptor cascade has been implicated as a major player via the cAMP signal in the control of melanogenesis. Only very recently the beta-endorphin/mu-opiate receptor signal has been added to the list of regulators of melanocyte dendricity and melanin formation.

Autocrine catecholamine biosynthesis and the beta-adrenoceptor signal promote pigmentation in human epidermal melanocytes.

Earlier it has been shown that human proliferating/undifferentiated basal keratinocytes hold the full capacity for autocrine catecholamine synthesis/degradation and express beta2-adrenoceptors (beta2-AR). In this report, we show that human melanocytes also express all of the mRNA and enzymes for autocrine synthesis of norepinephrine but fail to produce epinephrine. So far, it was established that human melanocytes express alpha1-AR which are induced by norepinephrine yielding the inosine triphosphate diacylglycerol signal.

Capturing and profiling adult hair follicle stem cells.

The hair follicle bulge possesses putative epithelial stem cells. Characterization of these cells has been hampered by the inability to target bulge cells genetically. Here, we use a Keratin1-15 (Krt1-15, also known as K15) promoter to target mouse bulge cells with an inducible Cre recombinase construct or with the gene encoding enhanced green fluorescent protein (EGFP), which allow for lineage analysis and for isolation of the cells.

Perturbed 6-tetrahydrobiopterin recycling via decreased dihydropteridine reductase in vitiligo: more evidence for H2O2 stress.

To date there is ample evidence that patients with vitiligo accumulate millimolar concentrations of hydrogen peroxide (H2O2) in their epidermis as well as in their blood lymphocytes/monocytes. Several enzymes are affected by this H2O2 including catalase, glutathione peroxidase, and 4 alpha-carbinolamine dehydratase. The latter enzyme disrupts the recycling of the essential cofactor (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin (6BH4) for the aromatic amino acid hydroxylases as well as the nitric oxide synthases.

Increased epidermal functioning wild-type p53 expression in vitiligo.

Despite the lack of protective melanin and increased oxidative stress due to mM concentrations of epidermal H2O2 in vitiligo, there is no significantly increased risk for chronic actinic damage and non-melanoma skin cancer. Therefore the question arises, which protective mechanisms could be involved in the skin of these patients preventing the initiation of these cancers. Recently an overexpression of p53 has been shown in vitiligo.

Tyrosine hydroxylase isoenzyme I is present in human melanosomes: a possible novel function in pigmentation.

Both human epidermal melanocytes and keratinocytes have the full capacity for de novo synthesis of 6(R) L-erythro 5,6,7,8, tetrahydrobiopterin, the essential cofactor for the rate limiting step in catecholamine synthesis, via tyrosine hydroxylase. Catecholamine synthesis has been demonstrated in proliferating keratinocytes of the epidermis in human skin. This study presented herein identified for the first time the expression of tyrosine hydroxylase isozyme I mRNA within the melanocyte.