Search PubMed⌕ Search

Biomedical subjects

A C Chu

Publications and source records attributed to A C Chu.

At least 73 records · Page 4Linked to original sources
PubMed1992

T lymphocytes bearing the gamma delta T-cell receptor: a study in normal human skin and pathological skin conditions.

The aims of this study were to investigate the presence of gamma delta T cells in normal human skin, and the possible role of these cells in cutaneous reactions. Twenty-eight samples of normal skin from various sites, and 52 biopsies from inflammatory and neoplastic skin conditions were investigated by immunohistochemical techniques. In normal human skin gamma delta T cells were infrequently seen in the epidermis and dermis. In the inflammatory and neoplastic dermatoses, gamma delta T cells were occasionally present, accounting for 0-5% of CD3+ cells in most of the biopsies examined. In one case of pityriasis lichenoides chronica and one case of lichen planus gamma delta T cells were found to be increased, accounting for 15% of the CD3+ cells in each case. Dermal gamma delta T cells were markedly increased in three of six cases of Langerhans cell histiocytosis, with up to 30% of dermal CD3+ cells showing positive staining to an anti-T-cell receptor gamma delta monoclonal antibody. In two of these cases gamma delta T cells were seen in both the dermis and the epidermis. In two further cases dermal gamma delta T cells were not a prominent feature, but small clusters of epidermal gamma delta T cells were observed. T cells bearing the gamma delta T-cell receptor are thus not a major feature of normal human epidermis, unlike the murine system, where the great majority of epidermal lymphocytes express the gamma delta T-cell receptor.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidermis↗
PubMed1992

Pyoderma gangrenosum--response to topical nitrogen mustard.

We report a 69-year-old caucasian male patient with long-standing pyoderma gangrenosum; the lesions preceded the appearance of an IgA monoclonal gammopathy by 2 years. A number of systemic treatments, including high dose steroids and immunosuppressive agents, were poorly tolerated and resulted in serious side-effects. The skin and haematological conditions, however, were kept under control for 2 years with regular plasmapheresis. Pyoderma gangrenosum recurred as vascular access became exhausted but new lesions healed completely with topical application of 20% nitrogen mustard.

Administration, Topical↗
PubMed1991

Langerhans-cell histiocytosis--excellent response to etoposide.

We describe an adult with progressive LCH who received oral etoposide as primary treatment. The response is documented and the strategical implications of this drug in Langerhans-cell histiocytosis discussed. Langerhans-cell histiocytosis (LCH) is the term recognized since 1987 for the group of diseases previously designated histiocytosis X. It is not now regarded as a malignant neoplastic process and there is some evidence to suggest that it is due to abnormal immunity, but cytotoxic drugs and steroids are still the mainstay of systemic treatment. Etoposide (VP16) is a semisynthetic epipodophyllotoxin derivative effective in the treatment of malignancies of the monocyte-macrophage lineage and used in resistant or relapsed childhood LCH. There are no previous reports of its use as firstline monotherapy in adults with LCH.

Adult↗
PubMed1989

Sézary cell morphology induced in peripheral blood lymphocytes: re-evaluation.

In this study we examined the effect of mitogens and epidermal cells in inducing a Sézary cell morphology in normal peripheral blood lymphocytes. Peripheral blood mononuclear cells from six healthy volunteers were stimulated with the mitogens phytohemaglutinin and concanavalin A, and also cocultivated with human epidermal cell cultures. Incubation times with mitogens and epidermal cells were four days and stimulation of the lymphocytes by mitogens was confirmed by standard 3H-thymidine uptake. Standard transmission electron microscopy showed that in the mitogen-driven system 20% to 60% (33 +/- 15%) and in the epidermal cell-driven system 5% to 15% (8 +/- 4%) of the lymphoid cells exhibited mild to moderate indentation of the nuclei with nuclear contour indices (NCI) of 4.6 to 6.5 but no Sézary cells were observed (cells with NCI greater than 6.5 and up to 19.2). In the mitogen-stimulated preparation 2% to 5% (3 +/- 1%) of the lymphoid cells showed nuclear multilobulation resembling the cells seen in adult T cell lymphoma/leukemia. Incubation of mononuclear cells for longer periods of up to 4 weeks with mitogens and exogenous IL-2 resulted in no further morphologic changes. Using an indirect immunogold technique at the electron microscopic level, the cells showing nuclear indentation or lobulation were shown to bear both T helper (CD4) and T suppressor (CD8) cell phenotypes in a similar ratio to the total numbers of T helper and T suppressor cells present. Mitogens and epidermal cells are thus not able to induce a morphologic change to Sézary cells in normal peripheral blood lymphocytes.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

Chronic actinic dermatitis: an immunohistologic and photobiologic study.

Photobiologic, histologic, and immunohistochemical findings in 14 patients with chronic actinic dermatitis were compared. Grading of routine histologic features of involved skin demonstrated a spectrum of abnormalities ranging from changes resembling chronic dermatitis to those of cutaneous T cell lymphoma. Immunohistochemical staining showed dermal infiltrates to consist predominantly of T lymphocytes, with a significant trend toward lower CD4+/CD8+ ratios in cases with more florid histologic findings. Circulating CD4+/CD8+ cell ratios were normal in five patients and reduced in one patient. Photosensitivity extending to wavelengths longer than 340 nm was detected in eight patients, but the spectrum of photobiologic abnormality did not appear to correlate with either grading of histologic severity or variation in T cell subsets in lesional skin.

Aged↗
PubMed1989

A flow cytometric study of Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH), or histiocytosis X, is now generally considered to be a non-malignant condition. A flow cytometric (FCM) study of a single case has, however, been published which claimed to provide evidence to contradict this. The presence of DNA-ploidy as detected using this technique is a feature of malignant and pre-malignant disease. In this reported single case, DNA-ploidy was present but the clinical features of this patient were atypical for LCH. We have performed a FCM study of the DNA of nine biopsies of LCH lesions from six patients with well-established disease. In addition, in one of these, fresh tissue studies including the use of an anti-CD I monoclonal antibody to specifically label the LCH cells were performed. In all cases the DNA content of the cells was entirely normal. We therefore found no evidence that LCH is a neoplastic disorder.

Adult↗
PubMed1989

UVA sunbeds: tanning, photoprotection, acute adverse effects and immunological changes.

The effects on 31 normal subjects following exposure to sunbeds containing UVA lamps with minimal UVB emission have been compared in a double-blind study with the effects on nine control subjects of a similar exposure course three times weekly for 4 weeks to sunbeds emitting visible light. On previously untanned areas, all those subjects on active treatment developed a mild tan; in tanned areas they all developed a moderate tan, while all control subjects developed a minimal to mild tan. The mean protection factor against later UVB-induced erythema was 3.2 +/- 0.3 after the active course and 1.6 +/- 0.2 among the controls. Significantly more frequent adverse cutaneous effects for active subjects were pruritus, erythema, freckling, burning sensation, dryness and polymorphic light eruption. Cutaneous Langerhans cell numbers, and blood CD3+ (pan T-cell) and CD4+ (helper T-cell) lymphocyte subsets were reduced in both active and control groups. CD8+ (cytotoxic/suppressor T-cell) counts were similarly but not significantly reduced in both groups. Pityrosporum yeast counts were significantly reduced in both groups. The changes found in both groups seem attributable to small amounts of UVB emission from both active and control lamps.

Adolescent↗
PubMed1989

Polymorphic light eruption: an immunopathological study of evolving lesions.

Polymorphic light eruption (PLE) papules were successfully induced on previously affected sites in 11 out of 14 patients with PLE 4-20 h after single exposures to suberythemogenic doses of solar simulated radiation. Histological examination of biopsies performed 1 h, 5 h, 24 h, 72 h and 144 h post-irradiation revealed onset within 5 h of perivascular cellular infiltration. The infiltrate was dominated by lymphocytes in both early and established lesions, without evident epidermal pathology. Immunohistochemistry demonstrated a predominance of CD4+ cells in lesions up to 72 h post-induction, but later biopsies were dominated by a CD8+ infiltrate. Significantly increased numbers of dermal macrophages and CD1b+ cells were detected 1 h and 5 h post-irradiation, respectively. These findings are consistent with a delayed type hypersensitivity response underlying the pathogenesis of polymorphic light eruption.

Adult↗
PubMed1988

Comparison of peanut agglutinin and S100 stains in the paraffin tissue diagnosis of Langerhans cell histiocytosis.

We compared peanut agglutinin and S100 stains on paraffin embedded material from a variety of sites involved in Langerhans cell histiocytosis (LCH). The two techniques were comparable in terms of ease of performance, time taken and cost. Peanut agglutinin produced dense cell surface and paranuclear staining of the characteristic LCH cells seen in lesions, which was easier to distinguish than the more diffuse cytoplasmic staining produced by the S100 technique. This characteristic staining pattern is more specific than that for the S100 protein which is present in a variety of different cells, including some malignant histiocytes. We recommend that peanut agglutinin be used as a routine diagnostic test for all samples suspected of being LCH.

Histiocytosis, Langerhans-Cell↗
PubMed1988

Intralesional therapy of cutaneous leishmaniasis with sodium stibogluconate antimony.

One hundred and thirty lesions of cutaneous leishmaniasis in 60 patients were treated with intralesional injections of Pentostam and 30 lesions were left untreated as controls. The injections were given at 8-day intervals and the patients followed-up for 42 days. One hundred and four lesions (80%) needed one injection only, 20 (15.4%) needed two and six (4.6%) needed three injections. One hundred and twenty three of the treated lesions (94.6%) showed a good clinical response with complete healing or marked improvement within the follow-up period. None of the control lesions showed marked improvement or complete healing. Scarring was minimal or absent following healing of treated lesions. The only side-effect was some localized pain following the injection. We recommend intralesional Pentostam as a safe and effective method of treating acute cutaneous leishmaniasis.

Acute Disease↗
PubMed1987

Current controversies. Histiocytosis-X.

There are still many areas of controversy concerning Langerhans cell histiocytosis. This article addresses the main controversies and highlights the central factors of this disease, which further investigation should elucidate.

Diagnosis, Differential↗
PubMed1986

Immunologic differentiation of the Sézary syndrome due to cutaneous T-cell lymphoma and chronic actinic dermatitis.

Peripheral blood mononuclear cells from two well-defined groups of patients with the Sézary syndrome have been studied employing indirect immunofluorescent and indirect immunogold techniques in light and electron microscopy, using monoclonal antibodies against T-cell subpopulations. Four patients had chronic actinic dermatitis (CAD) of the actinic reticuloid variant, with erythroderma. Eight patients had cutaneous T-cell lymphoma. All patients showed the clinical features of the Sézary syndrome, including erythroderma, palmoplantar hyperkeratosis, and peripheral lymphadenopathy, and in all patients significant numbers (0.5-30.5 X 10(9) cells/liter) of circulating mononuclear cells were observed with Sézary cell morphology on light-microscopic examination of blood films. Major differences were observed in the circulating T-cell subpopulations in the two groups. In the erythrodermic CAD patients, there was a moderately elevated T-cell count (1.6 +/- 0.6 X 10(9) cells/liter; normal, 1.0 +/- 0.3 X 10(9) cells/liter) of which the majority of the cells was suppressor T cells (OKT8+) giving a very low helper:suppressor T-cell ratio of 0.1:1-0.36:1 (normal, 1.7:1-3.5:1). In cutaneous T-cell lymphoma, there was also an elevation of the T-cell count (9.5 +/- 12.9 X 10(9) cells/liter), but in these patients the predominant cell was the helper T cell (OKT4+) with a high helper:suppressor T-cell ratio of 3.7:1-98:1.

Antibodies, Monoclonal↗