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N Yawalkar

Publications and source records attributed to N Yawalkar.

47 records · Page 3Linked to original sources
PubMed1997

Human skin lymph derived from irritant and allergic contact dermatitis: interleukin 10 is increased selectively in elicitation reactions.

BACKGROUND: Recent reports suggested an immunomodulatory role for interleukin 10 (IL-10) in contact hypersensitivity. OBJECTIVE: To investigate if IL-10 is important in the regulation of irritant and allergic contact dermatitis (CD), IL-10 and interferon gamma (IFN-gamma) protein levels were measured in normal skin lymph, in lymph derived from irritant and allergic (primary sensitization and elicitation) CD and in skin blister fluid from an elicitation reaction. METHODS: A superficial lymph vessel was cannulated microsurgically on the lower leg of 18 healthy volunteers. Lymph was collected twice daily. Protein levels of IL-10 and IFN-gamma were determined using commercially available ELISA kits and messenger RNA was estimated by a reverse-transcriptase polymerase chain reaction (PCR) method. RESULTS: Whereas the IL-10 levels in lymph derived from irritant CD and primary sensitization of allergic CD, similarly to those obtained from normal untreated skin, remained below 4.4 pg/ml, the IL-10 levels increased manifold both in the primary allergic reaction (928.5 pg/ml) and the elicitation of allergic CD (124 pg/ml). The levels of IFN-gamma also increased in all volunteers exhibiting an eczematous skin reaction and showed a tendency to be inversely correlated with IL-10. Using a reverse-transcriptase PCR, the expression of IL-10 and IFN-gamma in cells from lymph and from blister fluid was examined. While signals for IFN-gamma were not found, specific transcripts for IL-10 were detected in all samples examined, indicating that cells circulating in the lymph may also contribute to the IL-10 production measured. The IL-10 mRNA signal, however, was markedly stronger in lymph and epidermal blister cells from the elicitation reactions as compared to the signal in lymph cells derived from normal skin and from the primary sensitization of allergic CD. CONCLUSION: IL-10 may limit and down-regulate elicitation reactions by inhibiting cytokine and antigen-presenting cell functions in the skin and in the skin-associated lymphoid tissue.

Adjuvants, Immunologic↗
PubMed1996

IL-12 gene expression in human skin-derived CD1a+ dendritic lymph cells.

Recent reports point to a role for interleukin-12 (IL-12) in regulating T- and NK-cell function, macrophage activation and initiation of Th1-type cell responses. We sought to determine whether CD1a+ dendritic cells of the skin, as major antigen-presenting cells, are a source of IL-12 and therefore important in the initiation of Th1-type cell responses. To investigate this hypothesis, we cannulated microsurgically a skin-draining lymph vessel in the lower legs of five healthy volunteers. Altogether, ten different samples, each consisting of 1 x 10(6) lymph cells, were investigated. In four of the ten samples. CD1a+ dendritic lymph cells were isolated and purified by positive selection using mouse anti-CD1a monoclonal antibodies and sheep anti-mouse antibody-coated Dynabeads. Messenger RNA levels were estimated using a nested reverse transcriptase polymerase chain reaction (nRT-PCR) method. Total RNA was extracted from the cells, reverse transcribed to cDNA and amplified using specific primers for the target gene. Amplified products were sized by electrophoresis and visualized by ethidium bromide. Expression of IL-12 p40 and p35 mRNA was detected in all samples, both whole lymph samples and the highly enriched CD1a+ dendritic cell population. Our findings demonstrate that human skin-derived CD1a+ dendritic lymph cells produce IL-12 mRNA and may therefore be an important source of IL-12. Thus one might speculate that these CD1a+ dendritic cells, through their IL-12-producing capacity, might significantly influence the balance of Th1 versus Th2 reactions ultimately occurring.

Adult↗
PubMed1996

GM-CSF mRNA and protein in human skin-derived lymph.

GM-CSF together with IL-1 beta and TNF-alpha has been shown to play a key role in the maturation of LC in vitro. To investigate the presence of GM-CSF, IL-1 beta and TNF-alpha in human skin-derived lymph, we cannulated microsurgically a superficial lymph vessel on the lower leg of six healthy volunteers. Messenger RNA levels were estimated by a reverse transcriptase polymerase chain reaction (RT-PCR) method. From a total of 20 different samples, each consisting of 10(6) lymph cells, total RNA was extracted, reverse transcribed to cDNA and amplified using specific primers for the target gene. Amplified products were sized by electrophoresis and visualized by ethidium bromide. Specific transcripts for GM-CSF were detected in all lymph samples, indicating that circulating human skin-derived lymph cells express GM-CSF mRNA. A mean level of 11.5 +/- 2.1 pg/ml GM-CSF was detected in the lymph samples examined, as determined by a sensitive ELISA. In contrast to GM-CSF, occasional weak mRNA signals together with a mean level of 2.7 +/- 2.2 pg/ml were found for IL-1 beta, and neither specific transcripts nor protein were detected for TNF-alpha. Thus, our results demonstrate that afferent skin lymph cells constitutively express GM-CSF.

Adult↗
PubMed1996

Constitutive expression of both subunits of interleukin-12 in human keratinocytes.

Interleukin-12 (IL-12), a heterodimeric molecule consisting of disulfide-linked 35- and 40-kDa chains, is secreted by a variety of cells including macrophages and B cells. While keratinocytes have recently been demonstrated to produce IL-12 after stimulation with phorbol-12,13-dibutyrate as well as trinitrochlorobenzene, the constitutive expression of the two IL-12 subunits has remained controversial. In this study, we investigate if cultured keratinocytes derived from human epidermis and the follicle outer root sheath constitutively express IL-12. Total RNA was reverse transcribed to cDNA and amplified using a highly sensitive nested reverse transcriptase polymerase chain reaction. Both IL-12 p40 and p35 transcripts were detected in keratinocyte cultures. Moreover, low levels of the IL-12 p70 heterodimer were detected in the culture supernatants, as determined by a sensitive enzyme-linked immunosorbent assay. Since IL-12 is known to play an important role in the development of Th1 cells, the constitutive expression of mRNA for IL-12 in keratinocytes together with its secretion adds further evidence for a role of keratinocytes in immunological processes within the skin such as in contact hypersensitivity.

Base Sequence↗
PubMed1996

IL-1 beta protein in human skin lymph does not discriminate allergic from irritant contact dermatitis.

Recent data suggest a key rôle for IL-1 beta in the induction phase of allergic contact dermatitis. In the present study, the protein levels of IL-1 beta were measured in skin lymph derived from normal untreated skin as well as from irritant and allergic (induction and elicitation phase) contact dermatitis. IL-1 beta increased in the course of both types of contact dermatitis, displaying the highest levels in irritant CD. Using a reverse transcriptase-polymerase chain reaction, low signal strength of IL-1 beta mRNA was demonstrated in lymph cells derived from normal skin and allergic CD. In lymph cells collected 2 x daily during the induction phase of allergic contact dermatitis, no upregulation of the IL-1 beta mRNA signal was found. Isolated CD1a+ lymph cells derived from normal skin as well as from the induction and elicitation phase of allergic contact dermatitis did not express IL-1 beta mRNA. Our results demonstrate that in human skin lymph, the IL-1 beta profiles do not discriminate between irritant and allergic contact dermatitis and that besides resident epidermal and dermal cells, circulating lymph cells may also contribute to IL-1 beta protein production.

Adult↗
PubMed1996

Combined surgical and X-ray treatment for angiosarcoma of the scalp: report of a case with a favourable outcome.

Classic angiosarcoma is an uncommon malignant neoplasm of vascular differentiation which is highly aggressive. The diagnosis is often delayed and, since the response to treatment mainly depends on the size of the tumour, the prognosis is usually poor. Here we report a 76-year-old man in whom an extensive angiosarcoma of the scalp was treated by excision followed by wide-field radiotherapy. More than 4 years later there are no signs of local recurrence or of metastasis.

Aged↗
PubMedDate not supplied

Characterization of human skin-derived CD1a-positive lymph cells.

The phenotype and function of CD1a+ lymph cells is of considerable interest. By means of microsurgical lymph cannulation human lymph derived from normal skin was sampled. Cells were isolated and processed for immunocytochemistry, electron microscopy, flow cytometry and functional assays. The majority of the cells, (62%), were T cells. The other cells comprised CD1a+ cells (7%), monocytes/macrophages (8%), and B cells (1%); the remainder were erythrocytes or uncharacterized cells. The CD1a+ cells reacted with antibodies against protein S-100, HLA-DR, the Lag antigen, CD4, CD11a, CD11b, CD18, CD25, CD40, CD54, CD80 and CD86. Interestingly, a small prolow portion the of CD1a+ cells (about 5%) reacted with an antibody to CD14. The CD1a+ cells did not react with an antibody against human follicular dendritic cells nor were they CD19-, CD23-, E-cadherin- or factor XIIIa-positive. Both allogenic and antigen-specific T cell proliferation stimulated by antigen-presenting lymph cells were strongly inhibited by adding anti-CD80 and anti-CD86 antibodies. By electron microscopy Birbeck granules were detected in only 22% of the CD1a+ lymph cells and these cells exhibited an extensive ruffling of the surface. These findings demonstrate that CD1a+ lymph cells, which do not express the dermal dendritic cell marker factor XIIIa, resemble dendritic cells formerly designated as 'veiled' as well as lymphoid dendritic cells, suggesting that after migration to the regional lymphoid organs, Langerhans cells form a more differentiated population of dendritic cells specialized in sensitizing T lymphocytes. Our results add further support to the view that resident Langerhans cells may be precursors of lymphoid dendritic cells acquiring the final phenotype in the microenvironment of the lymph node.

Adult↗
PubMedDate not supplied

Increased coexpression of eotaxin and interleukin 5 in bullous pemphigoid.

While the presence of eosinophils in the skin lesions of bullous pemphigoid is well documented, the chemotactic factors responsible for eosinophil recruitment into the tissue still remain to be defined. In this study, eotaxin and interleukin-5 (IL-5) concentrations were determined in the blister fluid and sera of patients with bullous pemphigoid (acute and remission phase, n=6) in comparison with normal healthy controls (n=6) using the enzyme-linked immunosorbent assay (ELISA) technique. Eotaxin and IL-5 levels were increased in the blister fluid compared with the acute and remission phase sera, as well as compared with the sera of normal controls. In addition, immunoreactivity for eotaxin was predominantly found in the inflammatory cell infiltrate of lesional bullous pemphigoid biopsy specimens. In conclusion, the data provide evidence that co-operation of eotaxin and IL-5 may play an essential role in activating and recruiting eosinophils, which ultimately contribute to the tissue damage in bullous pemphigoid.

Aged↗
PubMedDate not supplied

Pathogenesis of drug-induced exanthema.

BACKGROUND: In vitro data derived from drug-specific T cell clones have revealed that heterogeneous T cell subsets with distinct phenotypes (CD4+ > CD8+) and cell functions (strong IL-5 production, cytotoxic potential) are generated. The aim of this study was to elaborate the relevance of these findings in vivo. METHODS: Skin biopsy specimens from drug-induced maculopapular exanthema and normal skin were analyzed for CD4, CD8, CD25, HLA-DR, CD54, perforin, granzyme B, IL-5 and IFN-gamma using immunohistochemistry. RESULTS: The majority of infiltrating lymphocytes in maculopapular drug eruptions were CD4+. Both CD4+ and CD8+ T cells expressed perforin and granzyme B and were partly located at the dermoepidermal junction and in the epidermis. In addition, strong immunoreactivity for IL-5 and moderate immunoreactivity for IFN-gamma were observed in the mononuclear cell infiltrate. CONCLUSIONS: Our data indicate that skin infiltrating T cells with a cytotoxic potential and the ability to produce IL-5 and IFN-gamma may contribute to the damage of keratinocytes and the activation of eosinophils, which are typical features of drug-induced maculopapular exanthema.

Drug Hypersensitivity↗