Balance of Treg vs. T-helper cells in the transition from symptomless to lesional psoriatic skin.

BACKGROUND: In the pathogenesis of psoriasis, proinflammatory T cells are strongly involved in the inflammatory process, where regulatory T-cell (Treg) function is impaired. OBJECTIVES: As effective Treg function is associated with a numerical balance between Treg and effector T cells, we wondered whether Treg/T-helper cell ratios may be associated with certain stages of the inflammatory process. We opted for the margin zone model as a dynamic approach. METHODS: From nine patients with chronic plaque psoriasis, 3-mm punch biopsies were obtained from the centre and margin of the lesion, perilesional skin and distant uninvolved skin. Skin biopsies of 10 healthy volunteers were included as a control. Samples were analysed using immunohistochemistry and immunofluorescence. RESULTS: In the transition from symptomless to lesional skin, a significant increase of CD3+, CD4+ and Foxp3+ cells was found. In seven of nine patients the ratio of Treg (Foxp3+) vs. CD4+ T cells was higher in the distant uninvolved skin than in the perilesional and lesional skin. Interestingly, the Foxp3/CD4 ratio in the distant uninvolved skin was even higher than in the skin of healthy controls. Notably, we found that most of the interleukin (IL)-17 expression was not related to CD4+ cells, but to mast cells. CONCLUSIONS: The relatively high Foxp3/CD4 ratio in symptomless skin of patients with psoriasis suggests an active immune controlling mechanism distant from the psoriatic plaque. In the margin and centre of the plaque the ratio appears skewed towards effector cells associated with inflammation. IL-17, an important driver of the psoriatic process, is mostly related to mast cells, and only sporadically to T cells.

Reflectance confocal microscopy: an effective tool for monitoring ultraviolet B phototherapy in psoriasis.

BACKGROUND: In vivo reflectance confocal microscopy (RCM) is a novel, noninvasive imaging technique which enables imaging of skin at a cellular resolution comparable to conventional microscopy. OBJECTIVES: We performed a pilot study to evaluate RCM as a noninvasive tool for monitoring ultraviolet (UV) B phototherapy in psoriasis. METHODS: In six patients with psoriasis, lesional and nonlesional skin was selected for RCM imaging using a standardized protocol. Well-known histological features of psoriasis were visualized: parakeratosis, acanthosis, agranulosis, papillomatosis, presence of epidermal inflammatory cells, increased number of papillary capillaries and increased capillary blood flow. RCM imaging was performed before the first irradiation with UVB phototherapy, after nine irradiations, at clearance and 12 weeks after clearance. In four patients, 4-mm punch biopsies were obtained and stained with haematoxylin-eosin. Additionally, immunohistochemical staining was performed with monoclonal antibodies specific for CD31, CD3, filaggrin, K16, Ki67 and CD1a for correlation to RCM images. RESULTS: There was a high correlation between clinical, RCM and histological features. Normalization of RCM and histological features corresponded highly to clinical improvement of psoriasis. CONCLUSIONS: This study is the first to establish the use of RCM as an effective tool for noninvasive monitoring of UVB phototherapy in patients with psoriasis. Potentially, RCM could be used in many other skin diseases for monitoring therapeutic response on a cellular level in a clinical or research setting.

Early development of descending supraspinal pathways: a tracing study in fixed and isolated rat embryos.

Early brainstem-spinal cord projections were studied in the rat using the carbocyanine dye DiI in fixed embryos and biotinylated dextran amine (BDA) in an isolated embryonic brain-spinal cord preparation. A system of staging embryos was used that allows direct comparison with data in other mammals. With both techniques it was shown that in embryos of at least 12 days of age (E12), i.e., at the time of closure of the posterior neuropore, already a variety of brainstem centers innervate the spinal cord. In the interstitial nucleus of the fasciculus longitudinalis medialis and various parts of the reticular formation - mesencephalic, pontine as well as medullary - DiI or BDA labelled neurons were observed. Mainly large immature, bipolar neurons were labeled. In later stages (E13, E14) the number of labeled neurons increased and more mature, multipolar cells were found. Labeled neurons were also observed in the vestibular nuclear complex and in the medullary raphe. Just below the cerebellum a conspicuous small group of neurons was found labeled in a position reminiscent of the locus coeruleus. Comparison with available data on the time of neuron origin of brainstem neurons suggests that interstitiospinal and reticulospinal neurons start projecting spinalwards shortly after they are generated. The earliest brainstem projections to the spinal cord all pass via the fasciculus longitudinalis medialis.