Sylvia Kukel

Evidence that defective interferon-gamma production in atopic dermatitis patients is due to intrinsic abnormalities.

The in vitro production of interferon-gamma (IFN-gamma) in 19 atopic dermatitis (AD) patients was compared with that of 12 controls. IFN-gamma production by phytohaemagglutinin (PHA) stimulated peripheral blood mononuclear cells (PBMC) was profoundly diminished in AD patients, whereas the proliferative response was similar to that of control PBMC. The addition of 40 U/ml of interleukin-2 (IL-2) to the cultures failed to restore IFN-gamma production. Similarly, removal of adherent cells also had no effect. Reduced IFN-gamma secretion was observed after stimulation with the CD3 monoclonal antibody OKT3, ionomycin + 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or with high levels of IL-2 (200 U/ml). There were increased proportions of CD4+ T helper/inducer cells and decreased proportions of CD8+ T cytotoxic-/suppressor cells and CD16+ natural killer (NK) cells in AD patients. This resulted in an increased CD4/CD8 ratio as compared with controls, but no correlation was observed between numbers of T cell subpopulations and IFN-gamma generation. However, a significant correlation was found between IFN-gamma generation in vitro and IgE serum concentration in AD patients. The data suggest that the decreased production of IFN-gamma by AD patients is due to intrinsic differences in capacity to produce this cytokine and is not the result of differences in regulatory cell interactions. Moreover, the findings indicate that decreased production of IFN-gamma may be an important factor in the pathogenesis of this disease.

Systemic interferon gamma treatment in severe atopic dermatitis

BACKGROUND Recent results suggest decreased interferon gamma (IFN-gamma) but high interleukin 4 (IL-4) production in patients with atopic dermatitis (AD). Because the relative activities of IL-4 and IFN-gamma seem to regulate the amplitude of the IgE response we suggested a role for IFN-gamma in the treatment of AD. OBJECTIVE The purpose of this study was to assess the efficacy of systemic IFN-gamma treatment in patients with severe AD. METHODS Patients with severe AD (n = 14) were treated with recombinant IFN-gamma for 6 weeks. During the study only basic local therapy with steroid-free hydrophilic or emollient ointments was allowed. RESULTS Eight patients (57%) showed marked clinical improvement during systemic IFN-gamma therapy. Four of these patients showed continuous improvement 3 months after treatment was discontinued. Mean total and antigen-specific serum IgE concentrations were not statistically different during and after treatment, whereas mean spontaneous IgE production in vitro was significantly lower after 6 weeks of IFN-gamma therapy. CONCLUSION Our results suggest that IFN-gamma treatment may represent a novel therapeutic approach in patients with severe AD.

Functional characterization of skin-infiltrating lymphocytes in atopic dermatitis.

Skin‐infiltrating lymphocytes (SIL) were isolated from skin biopsies of patients with hyperimmunoglobulin E (IgE) atopic dermatitis (AD) and expanded in vitro in the presence of IL‐2 in combination with IL‐4. Phenotypic analysis of skin‐derived cells revealed the predominance of CD4+ T helper/inducer phenotype in SIL populations. In 3H‐thymidine incorporation assays, SIL showed proliferation in response to IL‐2, IL‐3, IL‐4, ionomycin (Io)+ 12‐o‐tetradecanoyl‐phorbol‐13‐acetate (TPA) and OKT3 + TPA. OKT4 with and without TPA did not induce proliferation. Tumour necrosis factor alpha (TNF‐α) did not block proliferative responses of SIL to IL‐2 and IL‐4. Cultured SIL showed no cytotoxic activity against K562 and Jurkat target cells. Expanded skin‐derived T cells were tested for their capacity to secrete several cytokines in vitro. SIL secreted significant amounts of IL‐4, GM‐CSF and TNF‐α upon stimulation with mitogens but failed to secrete IFN‐γ. Io in combination with phorbolester induced the secretion of larger amounts of IL‐4, GM‐CSF, TNF‐α and low amounts of IFN‐γ. The data indicate that SIL derived from AD lesions were defective in their capacity to secrete IFN‐γ but were enriched in T cells capable of producing IL‐4 upon stimulation. The results support the possibility of a predominant‘TH2‐like’ cell‐mediated immune response in lesional skin of AD patients.

Progressive increase of CD7- T cells in human blood lymphocytes with ageing.

CD7 is one of the major surface antigens expressed very early during T cell ontogeny. Lack of CD7 expression on mature T cells is regarded as a classical feature of malignant T cells in certain forms of cutaneous T cell lymphoma. Previously, we identified a CD7‐ subset of peripheral blood T lymphocytes in normal human individuals. In this study we determined the portion of CD7‐ T cells in the peripheral blood of healthy volunteers ranging in age from 8 months to 90 years (n= 85) and in cord blood of full‐term infants (n= 14), Furthermore, this CD7‐ subset was characterized in detail by the use of MoAbs and three‐colour flow cytometry. In cord blood no CD7‐ T cells could be detected. After birth, percentage and absolute number of CD7‐ T cells increased with age. Independently of age, most CD7‐ CD3+ cells belonged to the CD4+ subpopulation. Focusing on the latter we could demonstrate the predominance of the CD45RO+CD45RA‐ phenotype in the CD7‐ subset. Furthermore, CD7‐ T cells contained a higher number of cells expressing activation markers and the CD57 antigen, but a reduced number of CD62L+ cells in comparison with CD7+ T cells.

Selective Alterations in Natural Killer Cell Subsets in Patients with Atopic Dermatitis

We examined the immunophenotypic characteristics of natural killer (NK) cell subsets in patients with severe atopic dermatitis (AD), rhinitis allergica (RA) and in healthy controls. Expression of CD16, CD56 and CD57 antigens on peripheral blood lymphocytes was evaluated by simultaneous double immunocytofluorometry. Our results showed significantly lower percentages of cells with CD16, CD56 and CD57 surface antigens in patients with AD. Furthermore subdivision of the AD group into two subgroups, AD1 and AD0 (with and without antigen-specific IgE antibodies against potent inhalative allergens, i.e. mite, grass, rye, birch, cat) revealed that patients of subgroup AD1 showed a more prominent decrease compared to that of subgroup AD0. Moreover, we found a significant negative correlation between the percentage of CD56 + CD16 + NK cells and total IgE levels in serum, which were significantly higher in patients of subgroup AD1 than in AD0. NK cell activity was deficient in patients with AD but there was no difference between both subgroups. These data indicate that considerable heterogeneity in immunologic regulation may exist in patients with AD with regard to their NK cell subsets.

Tumor‐infiltrating lymphocytes isolated from a Ki‐1–positive large cell lymphoma of the skin. Phenotypic characterization and analysis of cytokine secretion

Tumor‐infiltrating lymphocytes (TIL) were obtained from a biopsy of a patient with a Ki‐1–positive large cell lymphoma of the skin. Immunohistologic studies of the large anaplastic tumor cells showed an “aberrant” T “helper/inducer” phenotype (CD30+CD3–CD4+CD8–IL–2R+HLA–DR+). Using a cDNA probe for the constant region of the T‐cell receptor (TCR) beta gene, the cells were identified by their distinct monoclonal rearrangement of T‐cell receptor (TCR)‐beta DNA. Tumor cells isolated from biopsies were cultured in the presence of interleukin‐2 (IL‐2). Outgrowing lymphocytes were cloned, expanded in vitro, and 11 clones were subjected to phenotypic analysis: ten clones showed a predominantly CD4‐positive T “helper/inducer” phenotype whereas one clone expressed CD8 T “cytotoxic/suppressor” antigens. In contrast to the tumor cells, cells of all clones grown in vitro expressed the TCR‐associated CD3 complex. Furthermore, cells from all clones analyzed expressed CD5, CD7, CD45RO (UCHL1), CD11a (LFA‐1), CD25, and HLA‐DR antigens. Cells of two of ten CD4‐positive clones expressed CD45RA (2H4) in addition to UCHL1. T‐cell clones isolated from the tumor and grown in vitro exhibited individual DNA restriction band patterns different from that of a DNA tumor biopsy specimen. Therefore, the authors conclude that these T‐cell clones represent presumably nonmalignant TIL. All clones tested secreted interferon (IFN)‐gamma and tumor necrosis factor (TNF)‐alpha in vitro. Nine of 11 clones were found to secrete additionally IL‐2 and IL‐4 upon stimulation with phytohemagglutinin (PHA) whereas two clones did not secrete detectable amounts of IL‐4. Selective growth of TIL in the presence of IL‐2 opens the possibility to use these cells in adoptive immunotherapy of cutaneous T‐cell lymphoma (CTCL). Cytokines secreted by TIL cells in vitro (IL‐2, IL‐4, IFN‐gamma, TNF‐alpha) may be involved in their antitumorgenic activity. Moreover, these data implicate that CD4‐positive TIL derived from CTCL cannot be grouped into different subsets based on the production of IL‐2, IL‐4, IFN‐gamma, and TNF‐alpha. 68:2155‐2160, 1991.

Development, cytology, lipid storage and motility of the Malpighian tubules of the nymphal dragonfly, Aeshna cyanea (Müller) (Odonata : Aeshnidae)

The Malpighian tubules of nymphal Aeshna cyanea (Odonata : Aeshnidae) were examined by light and electron microscopy. The 1st-instar nymphs have only 3 branchless tubules. With proceeding nymphal stages, these lengthen and branch. Also, additional tubules bud from the gut and show the same pattern of growth and branching, until in the final instar up to 21 separate tufts of branched tubules are present. A serpentine trachea/tracheole and a cross-striated muscle are helically wound around each tubule in close apposition. Isolated tubules show twisting movements for several days. Contraction of the muscle is responsible for fast coiling movements, while the slow decoiling movements probably depend on elastic deformations of the accompanying trachea, the basal lamina and the tubule cells, the latter showing an elaborate cytoskeleton and multiple adhesive junctions. The tubular epithelium consists of 4 types of cells. The distal segment is composed of ion transporting cells and terminates with a short, solid tip segment of undifferentiated cells. The intermediate segment consists of lipid cells which are densely filled with triglyceride droplets, as revealed by thin layer chromatography. Lipid cells are already present in the 1st instar before the nymphs have taken up any food. In later instars, the renal lipid content varies to some extent with the nutritional state and is nearly depleted during metamorphosis. The proximal segment is the region of tubular branching and may be conceived as the collecting duct of each tuft. Its epithelium consists of mucocytes.