Decrease in CD8+ lymphocytes in atopic dermatitis is associated with a preferential loss of cytotoxic effector cells rather than suppressor inducer cells.
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Antibodies, Monoclonal↗
Biomedical subjects
M D Tharp
Publications and source records attributed to M D Tharp.
Mast cell and myofibroblast in wound healing.
Growing evidence in the literature indicates that mast cells are integrally involved in the process of dermal wound repair. They are resident cells of the normal dermis and have several cytokines stored in their granules that are stimulatory to fibroblasts. They also contain serine proteases that may be involved in remodeling of the extracellular matrix during healing. Mast cells are found in increased numbers in acute wounds and in certain chronic fibrotic diseases. Their influence on fibroblast growth and collagen production may be an important element in fibrosis. The effects of mast cell mediators on dermal fibroblasts are currently being explored by our laboratory and others. Myofibroblasts are implicated in the phenomenon of wound contraction. These phenotypically altered fibroblasts express some features of smooth muscle cells, notably actin filaments, and are abundant in granulation tissue. It has been proposed that they are responsible for wound contraction and possibly certain types of contracture. However, this hypothesis has been challenged by studies demonstrating the presence of myofibroblasts in wounds that do not contract, or the process of contraction in vitro in the absence of myofibroblasts. At this time the issue remains open to debate and further research.
Fibroblasts↗
Detection of decreased cytotoxic effector CD8+ T lymphocytes in atopic dermatitis by flow cytometry.
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Adult↗
Growth of human basal cell carcinomas transplanted to C57/Balb/C bgJ/bgJ nu/nu (beige-nude) mice.
The purpose of this study was to measure growth parameters of transplanted basal cell carcinoma (BCC) to beige-nude mice during a 4-month observation time. Forty male beige-nude mice were transplanted with human BCC with our reported subcutaneous implantation technique. Initial volume and wet weight were determined for each tumor. The tumors were measured every 2 weeks by calipers with a final volume determined at 120 days, at which time the tumors were harvested, weighed, and processed for routine histology. Thirty-two tumor sites were positive for persistent tumor at harvest. Tumor volumes declined by an average of 51% and average tumor weight by 33%. There were increased numbers of mast cells surrounding the BCC tumor lobules. These results indicate that BCC can survive for 120 days in the beige-nude mouse.
Animals↗
IgE and immediate hypersensitivity.
Tissue mast cells play a central role in immediate hypersensitivity reactions. The clinical manifestations of these reactions appear to be dependent, in large part, on the anatomic location of the stimulated mast cells and the type of mediators released. In vivo and in vitro studies indicate that the tissues in which mast cells reside may greatly influence their biochemical composition, expression of surface receptors, and response to potential stimuli. Although all human mast cells in different organs store similar concentrations of histamine, heparin, and tryptase, cutaneous mast cells appear to be the predominant source of mast cell-derived chymase. Furthermore, at the time of stimulation, human skin mast cells predominantly form PGD2, whereas lung and intestinal mast cells generate LTB4, LTC4, and PGD2. Functional studies indicate that human cutaneous mast cells differ from human lung, heart, and intestinal mast cells. Skin mast cells are responsive to a variety of immunologic and nonimmunologic stimuli in vitro, whereas human pulmonary, cardiac, and intestinal mast cells are relatively refractory to many of these stimulatory signals. Taken together, these observations indicate that mast cells may assume different, and possibly specialized, functions within a specific tissue. Such site-to-site variation potentially could have important clinical significance, to the extent that information gained from mast cells in one organ may not be applicable to a mast cell population in a different tissue. Furthermore, these differences among human mast cells may not be confined to their biochemical composition and responses to various stimuli, but also may extend to the effectiveness of different anti-allergic preparations. Therefore, these observations underscore the importance of continued detailed investigation of human mast cells from different anatomic sites.
Humans↗
Chronic urticaria associated with exogenous thyroid use.
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Angioedema↗
The interaction between mast cells and endothelial cells.
Mast cells (MC) are widely distributed throughout different organs with a relative predilection for potential portals of entry into the host. In tissues, MC are generally concentrated around small blood vessels and lymphatics, as well as nerves and glandular tissue. This close association with vascular structures suggests an important interaction between MC and endothelial cells (EC). Tissue MC are known to generate and release a number of mediators including histamine, prostaglandin D2, and leukotrienes that induce vasodilatation and increased vascular permeability. These MC-mediated effects on vessels may enhance responses to tissue injury or infection by facilitating the deposition of plasma components and inflammatory cells into involved sites. Important interactions between MC, EC, and peripheral nerves also occur. MC-derived histamine and possibly other mediators induce axon reflexes in unmyelinated sensory nerves leading to the release of neurotransmitters such as substance P, calcitonin gene-related peptide, and adenine nucleotides. These neurotransmitters exert direct effects on blood vessels, and in some instances, may act as MC stimulators. In vitro studies indicate that MC also affect EC growth and new blood vessel formation. Mast cell-derived heparin has been implicated as an important cofactor in tumor-induced angiogenesis, whereas histamine has been reported to augment human dermal EC growth in culture. The recent identification of a tumor necrosis factor-like peptide in MC and the reported cytostatic effects of TNF on EC suggest that MC may inhibit the proliferation of these cells under certain conditions. Taken together, these observations indicate that the interactions between MC and EC are important in both physiologic and pathologic events.
Animals↗
Studies of connective tissue mast cell-mediated cytotoxicity.
Although mast cells have been implicated in mediating antitumor activity, the kinetics, mechanism(s), and suspectibility of different tumors to mast cell-mediated cytotoxicity have not been defined. Rat connective tissue mast cells (CTMC) of greater than or equal to 99% purity were investigated in vitro and found to express maximal spontaneous cytotoxicity against the mouse fibrosarcoma cell line WEHI-164 (56.0% +/- 2.1 SEM), the ultraviolet B (UVB)-induced, cutaneous fibrosarcoma 5C25 (34.7% +/- 3.4 SEM), and the human renal cell tumor Currie (26.8% +/- 2.0 SEM) at an effector to target (E:T) ratio of 80:1. Kinetic studies of CTMC-mediated cytotoxicity demonstrated significant detectable lysis against these tumors within 8 h, which was maximal by 16 h. Binding experiments showed that CTMC formed conjugates with all three lytic-sensitive targets; however, CTMC also attached to the lytic-resistant target YAC-1, indicating that conjugate formation alone is not sufficient for mast cell-mediated cytotoxicity. At two different concentrations, mast cell granules (MCG) lysed WEHI-164 (36.5% +/- 6.8 SEM) and 5C25 (34.4% +/- 6.9 SEM), but were only slightly cytotoxic (5.7% +/- 2.9 SEM) against Currie. A potential role for tumor necrosis factor-alpha (TNF-alpha) in CTMC-mediated cytotoxicity also was investigated. Polyclonal antibodies to TNF-alpha greatly reduced CTMC and TNF-mediated lysis of WEHI-164, but only partially inhibited CTMC killing of the slightly TNF-sensitive 5C25 tumors, and had no effect on CTMC cytolysis of Currie. Thus, this study demonstrates that CTMC mediate cytotoxicity in vitro by both TNF-associated and TNF-independent mechanisms. We conclude that CTMC are capable of mediating antitumor activity and that this effect may be important for tumor surveillance in the skin and other sites.
Cell Line↗
Ultrastructural morphometric analysis of lesional skin: mast cells from patients with systemic and nonsystemic mastocytosis.
Lesional skin mast cells from some patients with mastocytosis appear morphologically atypical; however, these subjective differences have not been quantified. Herein we describe an objective method for analyzing cutaneous mastocytosis mast cells by a combination of morphometric analysis and electron microscopy. By this technique, lesional mast cells from patients with adult systemic mastocytosis had a significantly larger mean cytoplasmic area (53.3 microns2), nuclear size (20.4 microns2), and granule diameter (0.81 micron) when compared with mast cells from adults with nonsystemic mastocytosis (36.3 micron 2, 15.4 microns2, and 0.67 micron, respectively) and normal age-matched control subjects (34.4 microns2, 14.1 microns2, and 0.67 micron, respectively). Lesional skin mast cells from infants with nonsytemic mastocytosis were very similar to adult nonsystemic mastocytosis mast cells but differed by several parameters from mast cells in adults with systemic involvement. This study demonstrates that there are quantitative differences between lesional skin mast cells from patients with systemic mastocytosis and those with nonsystemic disease.
Adult↗
Ultrastructural morphometric analysis of human mast cells in normal skin and pathological cutaneous lesions.
Electron micrographs of human mast cells in normal neonatal and adult skin and in cutaneous lesions of basal cell carcinoma (BCC), hemangioma and mastocytosis were assessed by morphometric analysis. Using this quantitative histologic approach, adult skin mast cells were found to be significantly larger (47.7 microns 2 +/- 2.4 SEM vs. 38.3 microns 2 +/- 1.8 SEM, p less than or equal to 0.001) and have larger granules (0.63 micron +/- .02 SEM vs. 0.53 micron +/- .02 SEM, p less than or equal to 0.001) than infant mast cells while both mast cell populations had comparable nuclear sizes (13.7 microns 2 +/- 0.9 SEM vs. 14.3 microns 2 +/- 0.8 SEM) and numbers of cytoplasmic granules (72 +/- 4.0 SEM vs. 66 +/- 4.0 SEM). Morphometric analysis of mast cell infiltrates in the adult skin lesions of BCC and hemangioma revealed that these cells were larger than neonatal mast cells but were similar to normal adult controls. Cutaneous mast cells from 2 mastocytosis patients, however, had significantly larger mean cell surface areas (78.0 microns 2 +/- 3.4 SEM and 70.6 microns 2 +/- 3.2 SEM, p less than or equal to 0.001), nuclear areas (20.8 microns 2 +/- 1.1 SEM and 21.3 microns 2 +/- 1.2 SEM p less than or equal to 0.001) and granule diameters (0.82 micron +/- 0.4 SEM and 0.83 micron +/- .03 SEM, p less than or equal to 0.001) when compared with mast cells in normal adult skin and in the other pathologic lesions. No difference in the total number of cytoplasmic granules was observed in the different mast cell populations.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Linear cutaneous lesions of Kaposi's sarcoma: a clinical clue to the diagnosis of acquired immunodeficiency syndrome.
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Acquired Immunodeficiency Syndrome↗
Functional heterogeneity of human mast cells from different anatomic sites: in vitro responses to morphine sulfate.
The responses of human cutaneous, pulmonary, intestinal, and cardiac tissue mast cells to the histamine-releasing agent morphine sulfate (MS) were investigated in vitro. Human cutaneous mast cells released significant amounts of histamine in the presence of 1 to 100 mumol/L concentrations of MS. Histamine release was detectable within 5 minutes after challenge and was complete by 15 minutes. A maximal histamine release of 21.6% (+/- 1.4 SEM) was observed after stimulation with 100 mumol/L of MS. This MS effect was inhibited by the opiate receptor antagonist naloxone with a 59% inhibition detected at equimolar concentrations and an 88% inhibition occurring in the presence of a tenfold molar excess of naloxone. Naloxone did not alter the cutaneous mast cell response to the calcium ionophore A23187. Human mast cells derived from pulmonary, intestinal, and cardiac tissues, as well as blood basophils, did not release histamine after stimulation with 1 to 200 mumol/L of MS, whereas each of these cell preparations responded to an IgE-mediated stimulus. The results of this study demonstrate that cutaneous mast cells release inflammatory mediators after stimulation by MS, whereas mast cells residing in lung, heart, and gastrointestinal tissues do not. These observations indicate that human mast cells in different anatomic sites can vary in their functional responses.
Basophils↗
Quantification of cutaneous mast cells using morphometric point counting and a conjugated avidin stain.
Mast cells in normal human skin and in lesional cutaneous tissue from two patients with mastocytosis were quantified with the use of a morphometric point counting technic in combination with the mast cell-specific stain, conjugated avidin. Mast cells in normal human flank skin occupied a relatively small percentage of the dermal volume, with a mean value of 0.40% (+/- 0.14 SD), while a marked increase in mast cell content was demonstrated in cutaneous lesional tissue from two patients with the macular and nodular forms of mastocytosis (2.5% and 64.3%, respectively). In a comparative study with the use of morphometric analysis, conjugated avidin proved objectively to be as good as toluidine blue, and subjectively superior to this stain for mast cell identification in both human and murine skin. The combination of morphometric point counting and the conjugated avidin stain provides a useful tool for establishing the diagnosis of mastocytosis and is applicable to a variety of experimental systems.
Adolescent↗
In vitro functional reactivities of cutaneous mast cells from patients with mastocytosis.
Cutaneous mast cells from 3 patients with mastocytosis were evaluated for their morphologic characteristics and in vitro functional reactivities to different secretory agonists. By electron microscopy, mastocytosis mast cells appeared larger than normal skin mast cells, frequently had atypical, highly indented or bilobed nuclei, and each contained numerous, elongated cytoplasmic projections. Suspensions of mastocytosis mast cells were obtained from lesional skin biopsy specimens, and their response to both immunologic and nonimmunologic secretagogues was compared with mast cells from normal skin. Lesional skin mast cells had a net histamine release of 12.3% (+/- 1.3 SEM) and 31.1% (+/- 6.0 SEM) following stimulation with the purified human anaphylotoxin C3a and mouse monoclonal antihuman IgE antibodies, respectively. This specific release was similar to the responses observed in normal skin mast cells (11.5% +/- 4.5 SEM and 16.7% +/- 2.1 SEM, respectively). Mast cells from cutaneous lesions of mastocytosis also responded to the nonimmunologic secretagogues, morphine sulfate and calcium ionophore A23187 with a specific histamine release of 15.1% (+/- 1.2 SEM) and 39.8% (+/- 8.7 SEM), respectively. The results of this study demonstrate that mast cells from lesions of mastocytosis are morphologically atypical, but have a histamine content similar to normal skin mast cells and retain their functional reactivities to clinically relevant secretory stimuli.
Child↗
Diagnosis of mastocytosis subsets using a morphometric point counting technique.
Mastocytosis, a disease that varies in its clinical presentation, is usually documented by histologic examination of lesional skin. However, no universally accepted histopathologic criteria exist for establishing the diagnosis of this disease. We have combined the method of morphometric point counting with the mast cell-specific stain, conjugated avidin, to accurately quantify mast cells in cutaneous tissue sections of mastocytosis. Using this histologic approach, we found that macules, papules, and nodules of mast cell disease had from ninefold to nearly a 160-fold greater mast cell content than was observed in normal skin and in several other cutaneous disorders. This technique also permitted the objective histologic stratification of mastocytosis skin lesions according to their mast cell density. Morphometric point counting in conjunction with conjugated avidin offers a simple and accurate method for establishing the diagnosis of mastocytosis.
Avidin↗
Acute synovial fluid eosinophilia associated with delayed pressure urticaria: a role for mast cells?
We report a case of exercise induced joint effusion with synovial fluid (SF) eosinophilia of 9,540/mm3 in a patient with delayed pressure urticaria. The SF eosinophilia was an acute but transient event associated with some evidence of local complement activation. Histologic assessment revealed a normal synovial membrane but with no detectable intact mast cells. These observations suggest that mast cells and eosinophils acting in concert can cause joint inflammation.
Acute Disease↗
The spectrum of mastocytosis.
Mastocytosis represents a spectrum of clinical disorders that results from an aberrant proliferation of tissue mast cells. This disease process may be confined to the skin (cutaneous mastocytosis) or may involve multiple organs (systemic mastocytosis). Parameters that are useful in differentiating cutaneous from systemic disorders include patient age, symptom complex, and clinical signs. A wide range of clinical symptoms may be encountered in patients with mastocytosis which result from the release of pharmacologically potent mast cell mediators. Distinct cutaneous patterns resulting from skin mast cell infiltrates can be helpful in identifying patients with systemic involvement. The diagnosis of mastocytosis is confirmed by demonstrating increased tissue mast cells in involved organs. The overall prognosis for patients with proliferative mast cell disease is relatively good, although a small percentage are at risk for developing a fatal neoplastic disorder (malignant mastocytosis). Treatment of mastocytosis is directed at both inhibiting mast cell degranulation and blocking the potential systemic effects of released secretory products. Future therapeutic advances depend upon an improved understanding of the basic mechanisms involved in mast cell mediator release and the forces that govern mast cell growth and development.
Adult↗
Conjugated avidin binds to mast cell granules.
The glycoprotein, avidin, conjugated either to the enzyme horseradish peroxidase, or to the fluorochrome dyes, fluorescein or rhodamine, identifies the granules of mast cells in both tissues and cell suspensions. In the absence of prior fixation, mast cells were not identified with conjugated avidin; however, granules released from these cells were stained with this labeled glycoprotein. The specificity of avidin for mast cells was confirmed by the absence of conjugated avidin-positive cells in the skin of mice (S1/S1d) deficient in mature dermal mast cells. Electron microscopic studies confirmed that avidin binds specifically to individual mast cell granules rather than to other cellular structures. Rodent and human mast cells were readily stained with avidin conjugated to horseradish peroxidase or to either of the fluorochrome dyes. The conjugated avidin staining technique is a reliable and simple method for identifying rodent and human mast cells, one that is useful as both an investigative and a clinical tool.
Animals↗