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The COVID-19 crisis has seriously affected academic medical centers (AMCs) on multiple levels. Combined with many trends that were already under way pre pandemic, the current situation has generated significant disruption and underscored the need for change within and across AMCs. In this article, the authors explore some of the major issues and propose actionable solutions in 3 areas of concentration. First, the impact on medical students is considered, particularly the trade-offs associated with online learning and the need to place greater pedagogical emphasis on virtual care delivery and other skills that will be increasingly in demand. Solutions described include greater utilization of technology, building more public health knowledge into the curriculum, and partnering with a wide range of academic disciplines. Second, leadership recruiting, vital to long-term success for AMCs, has been complicated by the crisis. Pressures discussed include adapting to the dynamics of competitive physician labor markets as well as attracting candidates with the skill sets to meet the requirements of a shifting AMC leadership landscape. Solutions proposed in this domain include making search processes more focused and streamlined, prioritizing creativity and flexibility as core management capabilities to be sought, and enhancing efforts with assistance from outside advisors. Finally, attention is devoted to the severe financial impact wrought by the pandemic, creating challenges whose resolution is central to planning future AMC directions. Specific challenges include recovery of lost clinical revenue and cash flow, determining how to deal with research funding, and the precarious economic balancing act engendered by the need to continue distance education. A full embrace of telehealth, collaborative policy-making among the many AMC constituencies, and committing fully to being in the vanguard of the transition to value-based care form the solution set offered.

Over at least the past 20 years, putative and real conflicts of interest (COI) at academic medical centers have been featured prominently in the lay press, often with reputational damage to individuals and institutions.1 The heightened focus of concern about alleged financial payments to physicians and academic institutions by pharmaceutical and device companies, coupled with increasing concern by medical students (most notably in the American Medical Student Association scorecard, which gave grades to medical schools ranging from A to F based on how well they performed in avoiding conflicts of interest with the pharmaceutical industry) shone a bright light on individual and institutional integrity.

The regulated expression of cell adhesion molecules (CAM) on endothelial cells is central to the pathogenesis of various inflammatory processes. Retinoic acid and synthetic derivatives have been demonstrated to exert antiinflammatory effects in cutaneous diseases. To determine modes of retinoid action in the modulation of inflammatory responses, we explored effects of all-trans-retinoic acid (t-RA) on the TNFalpha-induced expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and E-selectin in cultured human dermal microvascular endothelial cells. Pretreatment with t-RA specifically prevented TNFalpha-induced VCAM-1 expression, but not ICAM-1 and E-selectin induction. t-RA significantly reduced VCAM-1-dependent T cell binding to TNFalpha-treated human dermal microvascular endothelial cells as well. This differential modulation of TNFalpha-induced CAM expression by t-RA was reflected at steady state mRNA levels and in nuclear run-on studies. In transcriptional activation studies, the TNFalpha-mediated activation of the human VCAM-1 promoter was inhibited after t-RA treatment, while the ICAM-1 promoter activation was unaffected, indicating that the selective inhibition of CAM expression is regulated in part at the level of gene transcription. Furthermore, the transcriptional inhibition by t-RA appears to be mediated by its effects upon the activation of NF-kappaB-dependent complex formation. Analysis of protein-DNA binding assays revealed marked inhibition of specific NF-kappaB-dependent binding to the tandem NF-KB sites of the VCAM-1 promoter, but not to the functional NF-kappaB motif of the ICAM-1 promoter. The specific inhibition of cytokine-mediated VCAM-1 gene expression in vitro may provide a potential basis by which retinoids exert their biological effects at sites of inflammation in vivo.

Thrombospondin-1 (TSP-1), 450-kDa glycoprotein secreted by platelets and endothelial cells at sites of tissue injury or inflammation, plays an important role in angiogenesis, inflammation, and vascular occlusive skin diseases. Many of the physiologic and pathologic activities of TSP-1 are dependent upon its interactions with endothelial cells. To better understand the basis of these activities, we examined the mechanisms mediating the binding of human dermal microvascular endothelial cells (HDMEC) to immobilized TSP-1. HDMEC bound to but did not spread on TSP-1 in a concentration-dependent manner. Monoclonal antibodies (MoAbs) which recognize two purported TSP-1 binding proteins, CS36 and the alphav integrin chain, or TSP-1-derived peptides CGRGDS and CSVTCG, alone or in combination with heparin, did not inhibit HDMEC adhesion to immobilized TSP-1. Furthermore, CSVTCG-ovalbumin conjugates failed to support HDMEC adhesion. Although RGD-containing peptides immobilized on plastic wells supported HDMEC binding, they also induced cell spreading not characteristic of cell binding to TSP-1 and binding was inhibited by free RGD peptide. Two MoAbs against different domains of TSP-1 (A 4.1 and C 6.1) failed to block HDMEC binding to TSP-1, but both MoAbs inhibited G361 human melanoma cell binding to TSP-1 by 60%. Acid treatment of TSP-1 almost completely abrogated its ability to support HDMEC binding, while acid treatment inhibited G361 binding by 50%. However, either antibody completely abrogated G-361 cell binding to acid-treated TSP-1. These data demonstrate that HDMEC bind to immobilized TSP-1 in an RGD- and CSVTCG-independent manner via an acid labile epitope(s) which recognized via a receptor or receptors distinct from CD36 or alphavbeta3 integrin receptor.

As part of the inflammatory response, the localization of leukocytes depends to an important degree on cytokine-induced expression of vascular cell adhesion molecule-1 (VCAM-1) on endothelial cells (EC). We have previously shown that VCAM-1 expression is induced on human umbilical vein EC (HUVEC) by both tumor necrosis factor alpha (TNF- alpha) and interleukin-1 alpha (IL-1 alpha), whereas on human dermal microvascular EC (HDMEC) only TNF alpha results in VCAM-1 expression. To explore molecular mechanisms responsible for these contrasting patterns of VCAM-1 induction in HUVEC versus HDMEC, we performed transcriptional activation studies with VCAM-1-based reporter constructs and in vitro binding assays using two adjacent NF-kappa B binding sequences of the VCAM-1 promoter as a DNA probe. Previous studies have established that these NF-kappa B motifs are required for cytokine-induced VCAM-1 transcription, and may further mediate cell- specific VCAM-1 gene activation by cytokines. The findings reported here demonstrate a significant HDMEC-specific attenuation of VCAM-1 gene transcription in response to IL-1 alpha, but not TNF alpha. An upstream VCAM-1 gene regulatory region distinct from the NF-kappa B sites appears to function as an IL-1 alpha-mediated transcriptional repressor within HDMEC. This repressor region conveys IL-1 alpha- dependent, but not TNF alpha-dependent, inhibition of transcription driven by a heterologous cytokine response element and promoter.

Endothelial cells rest on a basement membrane that anchors them to the vessel wall. The alpha 6 beta 4 integrin complex has been described on epithelial cells, frequently localizes to basement-membrane structures, and appears to play a role in binding epithelial cells to laminin. We have determined that human microvascular endothelial cells express the beta 4 integrin chain in vivo and that it preferentially localizes to the endothelial basement membrane. Human microvascular endothelial cells and human umbilical vein endothelial cells also express cell-surface beta 4 in vitro. In addition, the expression of beta 4 appears to be polarized to the undersurface of endothelial cell monolayers in vitro, mimicking its in vivo localization. Stimulation of microvascular endothelial cells with basic fibroblast growth factor or phorbol 12-myristate 13-acetate, agents previously shown to induce endothelial cell migration in vitro, resulted in a marked decrease in cell-surface expression of the beta 4 integrin chain, associated with a decrease in beta 4 mRNA. These data demonstrate that human endothelial cells express the beta 4 integrin chain in vivo and in vitro, the expression of this integrin chain is polarized, and its expression is regulated on microvascular endothelial cells by factors important in wound healing and vascular regeneration.

Although a portion of ultraviolet light (UV) penetrates into the dermis, histologic changes that occur within the dermal microvasculature have largely been attributed to the elaboration of biologic substances, such as interleukin 1 (IL-1), from other constitutive cells of the skin, as opposed to a direct effect of UV on the endothelial cell. As a potential model for understanding early molecular events occurring in UV-induced cutaneous inflammation, we have examined the direct effects of UVB, as well as cytokine-positive controls, upon human dermal microvascular endothelial cells (HDMEC) cell adhesion molecule (CAM) gene expression. Cultured HDMEC were exposed to varying dosages of UVB, and examined for cell surface and mRNA expression of the CAMs intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin (formerly ELAM-1). Following UVB exposure, dose-dependent increases in baseline cell surface expression of ICAM-1 were demonstrated by fluorescence-activated cell sorter analysis with concomitant increases in ICAM-1 mRNA, as shown by Northern blot analysis; there was no induction of either E-selectin or VCAM-1. The UVB-induced ICAM-1 upregulation could not be blocked by antibodies to IL-1 or tumor necrosis factor alpha (TNF-alpha). In fact, ICAM-1 gene regulatory region based CAT reporter gene plasmids, including constructs containing IL-1- and TNF-alpha-responsive elements, did not display increased CAT expression after transfection into HDMEC followed by UVB exposure, though control cytokine-treated transfectants did. Thus, UVB selectively upregulates ICAM-1, but not E-selectin or VCAM-1, mRNA and cell surface expression in HDMEC, and this upregulation is not dependent upon the autologous secretion and activity of either IL-1 or TNF-alpha.

E-selectin is an inducible endothelial cell adhesion protein that is a critical element in the binding of leukocytes to activated endothelial cells. It is induced by a variety of pro-inflammatory soluble substances including interleukin-1 (IL-1), tumor necrosis factor (TNF), or bacterial li- popolysaccharide (LPS). In vitro studies of large vessel endothelial cells demonstrate that stimulation with TNF or IL-1 leads to a rapid, but transient, induction of E-selectin expression that disappears within 24 hours. However, in vivo studies have shown that microvascular endothelial cells persistently express E-selectin in chronic inflammatory states, particularly in the skin where it serves as a homing receptor for memory T cells. Stimulation of dermal-derived microvascular endothelial cells (HDMECs) with single doses of IL-1α, TNF α, or LPS resulted in transient but slightly more persistent expression of E-selectin than seen after stimulation of large vessel derived umbilical vein endothelial cells (HUVECs). However, stimulation of either HDMECs or HUVECs with repetitive doses of IL-1α, TNFα, or LPS in the presence of human serum or plasma resulted in persistent E-selectin expression in vitro . The persistent E-selectin cell surface expression was associated with persistent E-selectin mRNA expression and correlated with E-selectin-mediated HL-60 binding to endothelial cell monolayers. The effect of human Vasma or serum was dose dependent, and fractionation of human plasma by gel filtration demonstrated that the E-selectin persistence activity resolved into high and low molecular peaks. These data demonstrate that human endothelial cells are capable of persistent E-selectin expression in vitro and that factors in human serum or plasma are critical in preventing cytokine refractoriness and loss of E-selectin expression. This study provides a basis to resolve the apparent discrepancies between previous in vivo and in vitro dynamics of E-selectin expression.

Utilizing standard hybridoma techniques and a neutrophil chemotaxis assay for screening we produced a mouse monoclonal IgM antibody, 59/4, selected for specific inhibition of human neutrophil chemotaxis to the N-formyl-methionyl-leucyl-phenylalanine peptide (fMLP). Antibody 59/4 inhibited neutrophil chemotaxis to fMLP, but not human C5a or leukotriene B4. The antibody exhibited specific homogeneous binding to PMNs, heterogeneous binding to monocytes, and did not bind to lymphocytes in a pattern similar to the profile of N-formyl peptide binding in flow cytometric analysis. The antibody did not inhibit the binding of fluorescein-conjugated fMLPK or fML(3H)P ligands to neutrophils in flow cytometric or competitive binding assays. Other neutrophil functions including myeloperoxidase release and rosette formation with immunoglobulin or immunoglobulin C3b-coated sheep erythrocytes were not affected in the presence of antibody 59/4. These results suggest that 59/4 specifically inhibits chemotaxis to fMLP.

Endothelial cells are critical elements in the evolution of all types of cutaneous inflammation. They participate through the synthesis and secretion of pro-inflammatory cytokines, including interleukin 1 (IL-1), IL-6, and IL-8, as well as M-CSF, G-CSF, GM-CSF, gro alpha, and MCP. They also express a series of cell-surface proteins and glycoproteins known as cell adhesion molecules that allow circulating leukocytes to bind to endothelial cells and allow endothelial cells to bind to matrix proteins. The regulated expression of these molecules, including those in the integrin, immunoglobulin gene, and selection families, allows for the precise trafficking of circulating leukocytes to sites of inflammation, injury, or immunologic stimulation in the skin. Furthermore, emerging evidence clearly indicates that selected differences exist between endothelial cells of the microvasculature and those that line large blood vessels. These include differences in secreted products, differences in the expression of cell adhesion molecules, and differences in cytokine-induced regulation of commonly expressed cell adhesion molecules, among others. Thus, a precise delineation of the biology of cutaneous microvascular endothelial cells is important to our understanding of cutaneous inflammation.

We have examined the mechanisms by which tumor cells bind to endothelial cells utilizing cultured melanoma cells and microvascular endothelial cells derived from human dermis (HDMEC). The ability of biologic response modifiers (BRM) to modulate the adhesion of melanoma cells to HDMEC was defined and those results were compared with results from human umbilical vein endothelial cells (HUVEC). SK-MEL-2, WM266-4, and Hs 294T melanoma cells all bound to HDMEC and HUVEC monolayers and adherence of melanoma cells was enhanced in a dose- and time-dependent manner by the treatment of HDMEC with interleukin 1 (IL-1) alpha or tumor necrosis factor (TNF) alpha. Similar increases in binding to HDMEC or HUVEC were induced after BRM stimulation, although baseline melanoma cell binding to HUVEC tended to be slightly higher than to HDMEC. In contrast, whereas phorbol 12-myristate 13-acetate (PMA) augmented melanoma cell adherence to HDMEC, PMA failed to increase adherence to HUVEC. The alterations in melanoma cell binding were induced only after pretreatment of endothelial and not melanoma cells with PMA. Studies of the expression of cell adhesion molecules (CAM) on HDMEC and HUVEC using enzyme-linked immunosorbent assay showed that vascular cell adhesion molecule 1 (VCAM-1) is not induced by PMA on HDMEC and intercellular adhesion molecule 1 (ICAM-1) is downregulated on HDMEC by PMA treatment. Endothelial leukocyte adhesion molecule 1 (ELAM-1) is induced by PMA, IL-1 alpha, or TNFalpha, but its expression does not correlate with increased melanoma cell binding MoAb recognizing VCAM-1-inhibited TNFalpha-induced increases in melanoma cell binding to HUVEC. However, anti-VCAM-1 antibody failed to clock melanoma cell binding to PMA or IL-1 alpha-stimulated HDMEC and only partially inhibited melanoma cell binding to TNF alpha-stimulated HDMEC. This study demonstrates that PMA and IL-1 alpha-induced increases in melanoma cell adherence to HDMEC are not mediated via known CAM, including ICAM-1, VCAM-1, or ELAM-1, and may be affected through microvessel-specific novel proteins not previously described on endothelial cells.

Interactions between leukocytes and endothelial cells, particularly in the microvasculature, are important for the initiation and regulation of tissue inflammation. These interactions are regulated by the recognition of specific cell adhesion molecules (CAM) on both leukocytes and endothelial cells. In this study, we examined the modulation of cell surface expression of MHC antigens and the CAM intercellular adhesion molecule 1 (ICAM-1), lymphocyte function antigen 3 (LFA-3), and CD44 on human dermal microvascular endothelial cells (HDMEC) both grown in monolayers and differentiated into capillary-like structures on the basement membrane-like substrate matrigel. HDMEC grown in monolayers or differentiated on matrigel express comparable cell surface MHC class I, LFA-3, CD44, and ICAM-1. ICAM-1, but not LFA-3 or CD44, was increased in expression in a dose- and time-dependent manner by interleukin 1 (IL-1) alpha, tumor necrosis factor (TNF) alpha, lipopolysaccharide (LPS), or interferon (IFN) gamma. Comparable upregulation was observed both in cells grown in monolayers and cells differentiated on matrigel. IL-1 alpha, TNF alpha, and LPS increased ICAM-1 expression on average 100-200% whereas IFN gamma was somewhat less potent. Comparative studies with human umbilical vein endothelial cells (HUVEC) demonstrated consistently lower levels of ICAM-1 expression on HUVEC, but greater increases after cytokine stimulation. Pretreatment with dexamethasone or transforming growth factor (TGF) beta did not affect baseline expression of ICAM-1 or inhibit upregulation of ICAM-1 on HDMEC by IL-1 alpha, TNF alpha, LPS, or IFN gamma. Both IFN gamma and TNF alpha, but not IL-1 alpha increased MHC class I expression, whereas only IFN gamma induced the expression of HLA-DR on HDMEC. The effect of IL-1 alpha, TNF alpha, or IFN gamma was inhibited by antibody to the specific cytokine, but was unaffected by antibody to other cytokines. Additionally, IFN alpha or beta inhibited upregulation of HLA-DR by IFN gamma, but had no effect on the increased MHC class I or ICAM-1 expression mediated by this cytokine. These data demonstrate that the expression of CAM and MHC antigens on small vessel-derived endothelial cells is different from that observed on large-vessel HUVEC, is regulated by the presence of multiple cytokines operating via distinct pathways, and the expression and regulation of these proteins appear to be similar on cells that have been grown in monolayers to those morphologically differentiated into blood vessel-like structures.

The prevalence of thyroid dysfunction as measured by the presence of overt thyroid disease, abnormal results of thyroid function tests, or antithyroid antibodies was compared in patients with dermatitis herpetiformis (DH) and a normal control group who had the HLA-B8/-DR3 haplotype.The study population consisted of 56 patients with DH and 26 control subjects with the HLA-B8/-DR3 haplotype. All were examined for thyroid function abnormalities and thyroid autoantibodies.Patients with DH had a statistically significant increase in the prevalence of abnormal thyroid function test results and autoantibodies: 32% versus 4% for controls (Z = 2.01, p less than 0.02). In patients with DH, hypothyroidism was the most common thyroid abnormality (12 of 56) followed by hyperthyroidism (four of 56). Two patients had normal thyroid function test results with thyroid autoantibodies. Risk factors for thyroid abnormalities in patients with DH were increasing age (chi 2 = 6.55, p less than 0.02, significant) and the presence of thyroid microsomal antibodies. The HLA-B8/-DR3 haplotype was not a risk factor for thyroid abnormalities.The findings suggest that thyroid disease is independently associated with DH. Examination of patients with DH should include thyroid function tests along with assays for antithyroid antibodies.

Endothelial cells line the vessels and lymphatics of the body, acting as a barrier between the blood and extravascular tissue. These cells are, therefore, in a prime position to play a role in lymphocyte activation. Indeed, it has been shown that primary endothelial cells in culture are capable of presenting particulate and soluble antigens to T cells and that this response is not dependent on macrophages. Recently, we developed an immortalized line of human microvascular endothelial cells, CDC/EU.HMEC-1 (HMEC-1). This endothelial line has the advantage not only of being devoid of contaminating cells but also of being a continuous cell line and therefore not subject to a restricted number of useful passages. The focus of this study was to determine whether HMEC-1 cells (like primary endothelial cells) could present antigen to T cells in the absence of macrophages. We demonstrate that a cloned and purified endothelial cell line can independently provide all the necessary signals for antigen-specific T-cell activation.

Modulation of the expression of the alpha v beta 3 complex on human dermal microvascular endothelial cells (HDMEC) may be crucial in wound healing and angiogenesis. Therefore, we examined the influence of basic fibroblast growth factor (bFGF), transforming growth factor beta, and interferon-gamma (IFN-gamma) on the expression of this complex. Stimulation of HDMEC with bFGF increased cell surface expression of both alpha v and beta 3 in a dose- and time-dependent manner associated with the development of a spindled, elongated cell morphology. Northern blot analysis of HDMEC stimulated with bFGF demonstrated a marked increase in beta 3 but not alpha v mRNA expression. Incubation of HDMEC with transforming growth factor-beta or interferon-gamma alone resulted in modest decreases in cell surface alpha v beta 3, and co-incubation of HDMEC with bFGF and transforming growth factor-beta or interferon-gamma inhibited bFGF-induced changes in cell morphology, increases in cell surface alpha v beta 3 expression, and increases in beta 3 mRNA. These data demonstrate that both growth factors and pro-inflammatory cytokines alter the expression of alpha v beta 3 on microvascular endothelial cells and that these alterations correlate with changes in cell morphology.

It has only recently been appreciated that the level of gene expression of cell surface markers can be different in endothelial cells derived from different anatomical sites, and that these differences can persist in vitro. In this study, we identify an immunoglobulin gene superfamily member, neural cell adhesion molecule (NCAM), that is expressed on the cell surface of human dermal microvascular endothelial cells but not on umbilical vein, pulmonary vein, aorta, or pulmonary artery derived endothelial cells. By western blot analysis, we identified the 140 kD isoform of NCAM on the surface of human dermal microvascular endothelial cells (HDMEC) derived from dermis. Isolates of HDMEC from human foreskin reproducibly expressed high levels of cell surface immunoreactive protein. In contrast, endothelial cells from large vessels never expressed NCAM constitutively and could not be induced to express NCAM by three proinflammatory cytokines. Western blot analysis of membrane preparations of HDMEC indicated that NCAM protein migrated as a single species with a molecular mass of 140 kD. RT-PCR identified NCAM mRNA in HDMEC cells. The potential for expression of NCAM on small vessels in skin can be interpreted in different ways. Members of the immunoglobulin gene family, including ICAM-1, ICAM-2, and VCAM-1, can be expressed on the cell surface of all endothelial cells and serve as adhesion molecules for leukocytes. It is also possible that, by analogy, NCAM serves as a ligand for a receptor on leukocytes, particularly those that also express NCAM (e.g., natural killer cells). Alternatively, it is possible that NCAM expression permits endothelial cell-cell adhesion, enhancing the structural integrity of microvessels or facilitates neural interactions with microvascular endothelium.

We have recently reported the creation of the first immortalized cell line derived from human dermal microvascular endothelial cells (HMEC-1). In preliminary studies this line was found to closely resemble microvascular endothelial cells in regard to many phenotypic characteristics. Because two key functional features of endothelial cells are their ability to bind to peripheral blood leukocytes and extracellular matrix proteins via cell adhesion molecules, we have now characterized HMEC-1 in terms of expression and regulation of cell adhesion molecules of the integrin, immunoglobulin gene superfamily, and selectin families. HMEC-1 can either constitutively express or can be induced to express key integrins, including alpha-1, -2, -3, -4, -5, -6, and -V, as well as beta-1, -3, -4, and -5. They also express or are capable of expressing immunoglobulin gene superfamily molecules, such as intercellular adhesion molecule-1 and vascular cell adhesion molecule-1, and a member of the selectin family, E-selectin. A number of important cell adhesion molecules that are either constitutively expressed or that must be induced are regulated in a time- and dose-dependent fashion by selected cytokines. Experiments comparing the phenotypic characteristics of HMEC-1 with human dermal microvascular endothelial cells or human umbilical vein endothelial cells reveal HMEC-1 to have features of both small- and large-vessel endothelial cells.

CDC/EU.HMEC-1 (HMEC-1) cells provide a reliable source of human micro-vascular endothelial cells free of mycoplasma and viral infection. This cell line has potential for use in the further study of the endothelial cell modification of low-density lipoproteins and for anticholesterol drug evaluation assays. HMEC-1 cells will fill a gap that is present for in vitro investigations of cholesterol metabolism in conjunction with previously established hepatic, monocytic, or macrophage cell lines. This paper presents a simple assay that demonstrates a linear uptake of tritiated cholesterol by he HMEC-1 cells and shows that the cellular cholesterol load can be regulated using anticholesterol drugs.

Recently it has become recognized that cell adhesion is critical in many different cellular functions. The proteins involved in the cell-cell or cell-matrix interactions are known as cell adhesion molecules (CAMs). This article reviews some of the most important CAMs and emphasizes their importance in dermatology and in skin diseases.

In the past several years there has been a great resurgence of interest in the subject of circulating immune complexes (IQ)* by both basic scientists and clinical investigators. This interest has been stimulated by recent advances in the technology of detecting soluble ICs in biologic fluids and is reflected in the large number of recent medical publications relating to this subject (more than 500 in the past 5 yr). It has become apparent that soluble antigen-antibody complexes are present in a wide variety of disease states. For physicians who are not actively engaged in research involving the detection and evaluation of ICs the quality and potential significance of the large number of papers dealing with this subject may not be readily apparent. In many instances the relationship between the presence of ICs and a particular disease process is unknown. In this article evidence that circulating antigen-antibody complexes are capable of mediating pathologic tissue damage is reviewed, the principles of some of the currently used assays to detect the presence of circulating ICs are given, and the potential significance of some of the recently reported studies documenting the presence of soluble ICs in several se

To examine the relationship between the gluten-sensitive enteropathy (GSE) and IgA circulating immune complexes (CIC) in dermatitis herpetiformis (DH) a series of dietary gluten-challenge studies were performed in patients with DH and patients with ordinary GSE. Serial serum samples were monitored for IgA-, IgG-, and IgM-containing CIC levels. In the first study, 9 DH patients and 5 controls were fed 20 g of gluten flour as a breakfast meal on 1 of 2 consecutive study days. DH patients did not develop or increase their levels of CIC after gluten-challenge or gluten-free meals. There was no significant difference between the DH patients and the control group in regard to development of CIC. To evaluate the effect of dietary gluten in another form, 8 DH patients were given meals containing 100 g of boiled Canadian cracked wheat. Two patients with ordinary GSE were also challenged with cracked wheat. Again there was no elevation or induction of CIC above baseline determinations by gluten-challenge meals. These studies suggest that dietary gluten does not induce the formation of CIC in patients with DH.

Stratum corneum (SC) antibodies are directed against antigens in the SC of the epidermis and are known to occur in all normal human sera. They have been shown by indirect immunofluorescence to be frequently associated with upper cytoplasmic (U-Cyt) antibodies. We have recently identified keratin intermediate filaments (KIF) as antigens for U-Cyt antibodies. In this study we investigated whether KIF also bear antigenic sites for SC antibodies. Normal human sera that contained SC and/or U-Cyt antibodies by indirect immunofluorescence were studied. Using immunoblot techniques 3 selected sera were shown to bind to high-molecular-weight (HMW) KIF proteins which had been extracted from 2 different epidermal cell preparations, that is, human callus or epidermis from which the SC had been removed by tapestripping. The 3 test sera were absorbed on KIF which had been reconstituted in vitro from urea extracts from both epidermal substrates. As shown by indirect immunofluorescence, the SC and U-Cyt antibodies of all 3 sera were absorbed out with KIF from callus and with KIF from epidermis without SC. Immunoblot experiments, which are more sensitive than indirect immunofluorescence, demonstrated the absorption of anti-KIF protein antibodies of the 3 test sera on callus KIF and 2 of the sera on KIF obtained from epidermis without SC. This was shown by the lack of staining of the respective HMW KIF proteins with the postabsorption sera. With the third serum a marked reduction of antibody binding was found after absorption on KIF from epidermis without SC. These data indicate that KIF bear antigenic sites for SC antibodies.

Twelve patients with bone marrow failure, who were undergoing therapy with daily intravenous infusions of horse antithymocyte globulin, were studied for the development of serum sickness. Eleven of 12 patients developed typical signs and symptoms of serum sickness 8-13 days after the initiation of treatment. These included fever, malaise, cutaneous eruptions, arthralgias, gastrointestinal disturbances, and lymphadenopathy. Eleven of 12 patients developed high levels of circulating immune complexes during serum sickness. All 12 patients also had concomitant decreases of serum C3 and C4 levels. In addition to urticarial and/or morbilliform eruptions, 8 of 11 patients also developed a serpiginous band of erythema along the sides of the fingers, hands, toes, or feet as an early cutaneous sign of serum sickness. Direct immunofluorescence of lesional skin biopsies during serum sickness revealed deposits of immunoglobulin or complement in the walls of small cutaneous blood vessels in 3 of 5 patients. These findings indicate that circulating immune complexes play a central role in the pathophysiology of human serum sickness.

An approach to the assessment of reticuloendothelial function that quantitates clearance specifically mediated by membrane receptors for C3b and immunoglobulin (Ig)G has been applied in man. Clearance of isologous erythrocytes coated with IgM or C3b or coated with IgG were examined in patients with primary biliary cirrhosis (PBC), chronic hepatitis, or alcoholic cirrhosis and normal control subjects and compared with the clearance of aggregated human serum albumin. Clearance of these three types of particles varied independently. None of the patients studied had a defect in the clearance of aggregated albumin. No patient with PBC (0:6) had delayed clearance of IgG-coated erythrocytes; one of six patients with chronic hepatitis had delayed clearance of these cells. Indeed, four of six with PBC had increased rates of IgG-mediated clearance. In contrast, six out of six patients with PBC had an unequivocal defect in clearance mediated by C3b receptors. The patients with PBC varied widely in terms of duration of symptoms, degree of cholestasis, and histologic stage of disease. No defect of C3b-mediated erythrocyte clearance was found in the patients with chronic hepatitis or alcoholic cirrhosis. Furthermore, a patient with severe cholestasis secondary to large duct biliary obstruction exhibited normal C3b-mediated clearance. The defect in C3b-mediated clearance in PBC did not correlate with serum levels of individual complement components or inhibitors or with the presence of circulating immune complexes as measured by the Clq precipitation assay. Thus, measurements of receptor specific clearance, but not clearance of aggregated proteins, have revealed a highly specific defect in reticuloendothelial function in PBC.

This study was undertaken to determine if long-term hyposensitization causes late sequelae, particularly those reflecting aberrant immunologic responses. Atopic individuals receiving five or more years of hyposensitization with allergenic extracts showed no increased autoimmune, collagen vascular, or lymphoproliferative disease. In addition, chronic hyposensitization did not have adverse effects on immunologic reactivity as assessed by a number of immune parameters. Particularly noteworthy was the absence of immune complexes in the serum of patients undergoing long-term hyposensitization. This study represents the first systematic investigation of potential adverse effects of long-term hyposensitization.

Dermatitis herpetiformis is associated with the HLA-B8/DRw3 haplotype in over 90 per cent of patients, and various percentages have been reported to have circulating immune complexes. Since removal of immune complexes from the circulation is thought to depend on the Fc-receptor function of tissue macrophages, we studied this function by measuring the clearance of IgG-sensitized autologous erythrocytes in 16 patients with dermatitis herpetiformis, in normal controls with the HLA-B8/DRw3 haplotype, and in randomly selected controls. All patients were HLA-B8 positive, and all of 12 patients tested were HLA-DRw3 positive. Erythrocyte clearance was reduced in eight of the 16 patients, but did not correlate with immune-complex levels. Four of eight controls with HLA-B8/DRw3 also had delayed Fc-receptor-mediated clearance as compared with normal controls. In addition, both patients and HLA-B8/DRw3-positive controls had decreased percentages and total numbers of T cells bearing Fc receptors for IgG. These findings indicate a functional Fc-receptor defect associated with the HLA-B8/DRw3 antigens.

We have prospectively evaluated the clinical and immunological features of serum sickness in 35 patients treated for bone marrow failure with anti-thymocyte globulin (ATG 15 mg/kg/day) and methylprednisolone (1 to 1.5 mg/kg/day). Twenty-one patients were treated for 10 days and 14 were treated for 28 days. Clinical evidence of serum sickness developed in 30 patients (86%) and included fever and malaise (100%), cutaneous eruptions (93%), arthralgias (67%), gastrointestinal complaints (67%), cephalgia (57%), blurring of vision (37%), arthritis, (30%) and lymphadenopathy (13%). Clinical serum sickness began on day 7 +/- 1 (X +/- S.E.M.) and lasted for 10 +/- 2 days in the 18 affected patients receiving the shorter course of ATG. In the 12 affected patients receiving the longer course of ATG, serum sickness began on day 9 +/- 1. The earliest manifestations of serum sickness were fever, malaise, and cutaneous eruptions. Cutaneous findings consisted of morbilliform eruptions (n = 19) and urticaria (n = 1) or a combination (n = 8) that lasted 10 to 14 days. Twenty-one patients (75%) developed a highly characteristic serpiginous band of erythema and purpura along the sides of the fingers, toes, palms and soles 12 to 48 hours before other symptoms of serum sickness. Biopsies of lesional skin during the course of serum sickness revealed immune deposits (IgM, IgE, IgA and C3) in dermal vasculature in 7 of 9 patients. Immunological changes that occurred during the course of serum sickness included increased serum levels of IgG, IgM, IgA, and IgE. Circulating immune complexes, as measured by the C1q-binding assay, increased from a mean value of 12% to 45% on day 13 +/- 1. Complement levels (C3, C4, and CH50) decreased 50 to 80% from their baseline levels on day 10 +/- 2. Acute phase reactants increased: erythrocyte sedimentation rate, C-reactive protein and beta-2 microglobulin. Abnormal urinalysis developed in 17 patients (57%) over the course of serum sickness and included proteinuria, hematuria and hemoglobinuria on day 10 +/- 3. Hematopoietic response occurred in 43%. All 5 patients who did not develop serum sickness recovered from bone marrow failure. Our data document the clinical and immunopathological findings in human serum sickness and suggest that the principles of antigen-antibody interaction, complement activation, and resultant inflammatory response as seen in the previous animal studies are directly applicable to studies of patients with serum sickness.

We prospectively evaluated the clinical and immunologic features of serum sickness in 12 patients with bone-marrow failure treated for 10 days with intravenous infusions of horse antithymocyte globulin. Eleven of the 12 patients had signs and symptoms of serum sickness 8 to 13 days after beginning therapy with antithymocyte globulin. Eleven patients (including 10 of 11 with signs and symptoms of serum sickness) acquired circulating immune complexes, with peak levels occurring at 10 to 12 days. Serum C4 and C3 levels fell precipitously, with nadirs on the 10th day. Plasma levels of C3a anaphylatoxin were elevated in the four patients in whom it was measured. Eight of the 11 patients with signs and symptoms of serum sickness had a characteristic serpiginous erythematous and purpuric eruption on the hands and feet at the junction of palmar and plantar skin. Direct immunofluorescence of skin lesions revealed immune deposits (IgM, IgE, IgA, or C3) in the blood vessels of three of five patients. This study documents the immunopathology of serum sickness in human beings and describes a cutaneous marker for the disease.

C5a and its degradation product, C5a des Arg, elicit immediate cutaneous inflammatory reactions after intradermal injection. Histologically, these reactions are characterized by neutrophil-rich leukocytic infiltrates, leukocytoclasis, edema, and dermal mast cell degranulation. It has not been possible to assess in vivo the relative contributions of resident mast cells and circulating leukocytes to this reaction because the accumulation of leukocytes and degranulation of mast cells occur simultaneously after injection of these anaphylatoxins. To assess the role of mast cells in these inflammatory reactions, we have examined the reactivity of human skin selectively depleted of dermal mast cells by local corticosteroid treatment. Corticosteroid-treated skin became virtually devoid of dermal mast cells within 4–6 wk as assessed by light microscopy, immunofluorescence with fluorescein conjugated avidin, or electron microscopy. Mast cell-depleted skin demonstrated normal vasopermeability and vasodilatory responsiveness to intradermal injection of histamine, but the reactivity of these sites to the mast cell secretagogue, morphine, was absent. Moreover, no clinical reactions were detectable in mast cell-depleted human skin after intradermal challenge with 50 ng of either C5a or C5a des Arg, despite the fact that biopsies of these sites revealed substantial, neutrophil-rich infiltrates. These infiltrates were qualitatively and quantitatively identical to C5a or C5a des Arg-induced infiltrates in mast cell replete skin. This experimental approach in vivo has allowed the independent analysis of the anaphylactogenic and chemoattractant activities of human C5a and C5a des Arg in human skin, demonstrated the importance of dermal mast cells in these clinical responses, and shown that leukocytes can accumulate at these infection sites directly in response to these mediators.

The sera of 13 patients with mixed cryoglobulinemia were examined for the presence of circulating immune complexes with the 125I-C1q binding assay before and after precipitation of cryoglobulins. All 13 patients had increased C1q binding activity(>10%) prior to cryoprecipitation (mean C1q binding activity =69%) and 10 of 13 had increased C1q binding activity after precipitation and removal of cryoglobulin (mean C1q binding activity = 41%). Decrements in serum C1q binding activity caused by cryoprecipitation ranged from minimal to marked (1–73%). Since all of these sera contained IgM rheumatoid factor, 7 were treated with 2-mercaptoethanol, known to dissociate 19S IgM into its subunits, and then tested for C1q binding activity and rheumatoid factor. 2-mercaptoethanol eliminated rheumatoid factor activity in all cases, but C1q binding activity remained elevated in 6 to 7 sera, thus indicating the presence of immune complexes distinct form 19S IgM rheumatoid factor complexes. By contrast absorption of 9 mixed cryoglobulinemia sera with solid-phase protein A resulted in the disappearance of immune complex-like material from the test sera, suggesting that IgG is a major constituent of the C1q binding material. Addition of eluate from the solid phase protein A to normal sera resulted in the appearance of increased C1q binding activity. Hepatitis B surface antigen was detected in the protein A eluate of two of six patient tested, and antibody to hepatitis B surface antigen was detected in the protein A eluate of a third patient. These findings indicate that in addition to cryoglobulins patients with mixed cryoglobulinemia have circulating immune complexes that are noncryoprecipitable. The immune complexes contain predominantly IgG and are, in most cases, distinct form 19S IgM rheumatoid factor complexes. In some cases the immune complexes may contain hepatitis B surface antigen or antibody.

The role of circulating immune complexes in the pathogenesis of IgA nephropathy (Berger's disease) is controversial. Previous studies have shown that a minority of these patients have immune complexes, but the methods used have been able to detect only IgG- or IgM-containing circulating immune complexes. Using a sensitive specific Raji cell radioimmunoassay for IgA-containing circulating immune complexes, we have examined serum specimens from 12 patients with IgA nephropathy for the presence of IgA-containing circulating immune complexes. In addition, the Raji cell IgG assay and the 125I-C1q binding assay were used for the detection of IgG- or IgM-containing circulating immune complexes. Purified monoclonal antibodies against human IgA1 and IgA2 were used to determine the subclass of IgA present in renal biopsy specimens from five of these patients. Six of 12 (50 percent) patients had IgA-containing circulating immune complexes, whereas only two of 12 (17 percent) had positive results in the Raji IgG assay and one of 12 (8 percent) in the 125I-C1q binding assay. There was no correlation between serum IgA, C3 C4, or factor B levels and the presence or level of IgA-containing circulating immune complexes. None of the three patients with renal failure had circulating immune complexes of any type. Of the seven patents with disease duration of two years or less, five (71 percent) had IgA-containing circulating immune complexes and three (43 percent) had IgG- or IgM-containing complexes. In all five renal biopsy specimens examined for IgA subclass, diffuse heavy, mesangial deposits of IgA1 were seen, whereas IgA2 staining was absent or present in only trace amounts. These findings suggest that IgA1 is the predominant antibody in renal biopsy specimens from patients with IgA nephropathy. The finding of IgA-containing circulating immune complexes in these patients--and their more frequent occurrence in patients with early stages of the disease--suggests that IgA-containing circulating immune complexes may play a role in the pathogenesis of IgA nephropathy.

Detection of filarial antigen in circulating immune complexes from patient sera was performed by an enzyme immunoassay in which the immune complexes were precipitated in the cold with polyethylene glycol and then dissociated in an acid pH buffer before being added to an ELISA plate. The dissociated antigen bound to the plate where it could be detected by peroxidase-labeled polyclonal rabbit antifilarial antiserum. Control sera used for defining the specificity of the assay included sera with immune complexes not related to parasite infection with and without free parasite antigen added prior to polyethylene glycol precipitation as well as sera from normal individuals. Filarial antigen was detected in the circulating immune complexes from 10 of 28 patients with bancroftian filariasis residing in either the Cook Islands (subperiodic Wuchereria bancrofti) or India (periodic W. bancrofti). By immunoblotting, the most frequently identified filarial antigen in these complexes was an approximately equal to 200 kDa circulating antigen.

In vivo studies have shown that human C5a, a potent complement-derived anaphylatoxin and chemoattractant, produces immediate inflammatory reactions following intradermal injection in human skin. At concentrations within its potential physiologic range, intradermal injection of C5a elicits immediate wheal and flare reactions, increased vascular permeability, mast cell degranulation, and neutrophil-rich infiltrates. To assess the relative contribution of interacting cellular elements to C5a-induced inflammation in normal human skin, purified human C5a was tested intradermally in 8 patients with bone marrow failure (BMF). Reactions to C5a in patients with BMF were compared with responses at identical test sites in healthy volunteers and other patients with cutaneous disorders. Patients with BMF demonstrated significantly less wheal and flare reactivity following intradermal injection of C5a than controls (p less than 0.05 and less than 0.02, respectively). In these studies, patients with the greatest cytopenia generally showed the least cutaneous reactivity to human C5a. Biopsies of C5a test sites in patients with BMF revealed an absence of leukocytes in marked contrast to neutrophil-rich infiltrates observed at test sites in healthy volunteers. Avidin-fluorescent and/or Giemsa staining of skin biopsies revealed no difference between the number of dermal mast cells in patients with BMF and samples of normal human skin. In addition, skin test studies with histamine (2 micrograms) and morphine (5 micrograms) performed to assess cutaneous vascular and mast cell responsiveness in patients with BMF, normal volunteers and controls with rhinitis revealed no significant differences in cutaneous reactivity to these pharmacologic agents. These in vivo studies demonstrate that patients with BMF specifically exhibit decreased cutaneous reactivity to human C5a and suggest that neutrophils make an important and an immediate contribution to inflammatory responses elicited by this anaphylatoxin.

In this study we determined whether dermatitis herpetiformis patients whose skin contained linear IgA deposits differ from those whose skin contained granular IgA deposits with regard to the presence of gluten-sensitive enteropathy and with regard to the prevalence of certain histocompatibility antigens. We performed multiple Rubin tube intestinal biopsies on 11 patients, 6 with linear and 5 with granular IgA deposits. The gut biopsies were evaluated histopathologically in a blinded fashion. We found that none of the patients with linear deposits (5 with lamina lucida and 1 with sub-basal lamina deposits) h-d detectable jejunal abnormalities whereas all of those with granular deposits had jejunal abnormalitites (villous atrophy and increased numbers of intraepithelial lymphocytes). In parallel studies HLA typing was performed in 10 patients with linear IgA deposits and in 49 patients with granular deposits. Only 30% of those with linear deposits had HLA-B8, a prevalence not significantly different from that of the normal population (24%); in contrast, 88% of those with granular deposits had HLA-B8, a prevalence significantly greater than in the normal population ( less than 0.001). We therefore conclude that patients with linear IgA deposits have a disease which is pathophysiologically different from those with granular IgA deposits.

During the past eight years, twenty-five patients with pruritic urticarial papules and plaques of pregnancy (PUPPP) have been prospectively evaluated at our institution. This distinct eruption of the third trimester was most frequently seen in primigravidas. Lesions began on the abdomen in all patients, and 48% specified that initial lesions were localized to periumbilical striae distensae. Other common sites of involvement included the buttocks, hips, thighs, legs, and upper inner arms. The face was uniformly spared. Initial lesions were 1- to 2-mm erythematous papules that quickly coalesced to form urticarial plaques. Although pruritus was the major complaint of all patients, excoriations were very rare. Frequent applications of high-potency topical corticosteroids were generally effective in relieving pruritus and controlling the eruption. Systemic corticosteroids were efficacious in three patients with extensive disease. No severe maternal complications were documented. There were no cases of prematurity, postmaturity, or spontaneous abortion. Two congenital abnormalities and one developmental problem have been documented in children of these patients, but patient numbers preclude definitive interpretation of these findings. As much as 6 years of follow-up on nineteen patients revealed no recurrence of PUPPP in the postpartum period, during eight subsequent pregnancies, or upon exposure to oral contraceptives.

Four patients with epidermolysis bullosa acquisita were investigated using immunofluorescence, routine electron microscopic and immunoelectron microscopic techniques. Immunofluorescence studies demonstrated linear immunoglobulin and complement deposition along the dermal-epidermal junction. These findings are similar to those seen in skin of patients with bullous pemphigoid. Immunoelectron microscopic studies demonstrated that the immunoreactants were localized below the subbasal lamina-anchoring fibril zone of the basement membrane, thereby clearly distinguishing the immunopathology of epidermolysis bullosa acquisita from that seen in bullous pemphigoid. Indirect immunoelectron microscopic findings suggest that epidermal basal cells of affected patients may secrete the dermal substances to which the antibodies bind.