Human Diversity of Killer Cell Immunoglobulin-Like Receptors and Human Leukocyte Antigen Class I Alleles and Ebola Virus Disease Outcomes

We investigated the genetic profiles of killer cell immunoglobulin-like receptors (KIRs) in Ebola virus–infected patients. We studied the relationship between KIR–human leukocyte antigen (HLA) combinations and the clinical outcomes of patients with Ebola virus disease (EVD). We genotyped KIRs and HLA class I alleles using DNA from uninfected controls, EVD survivors, and persons who died of EVD. The activating 2DS4–003 and inhibitory 2DL5 genes were significantly more common among persons who died of EVD; 2DL2 was more common among survivors. We used logistic regression analysis and Bayesian modeling to identify 2DL2, 2DL5, 2DS4–003, HLA-B-Bw4-Thr, and HLA-B-Bw4-Ile as probably having a significant relationship with disease outcome. Our findings highlight the importance of innate immune response against Ebola virus and show the association between KIRs and the clinical outcome of EVD.     

Clonal dominance among T-lymphocyte infiltrates in arthritis

Synovial membranes in patients with rheumatoid arthritis as well as other types of chronic destructive inflammatory arthritis contain infiltrates of activated T lymphocytes that probably contribute to the pathogenesis of the disease. In an effort to elucidate the nature of these infiltrates, interleukin 2 (IL-2)-responsive T lymphocytes were grown out of synovial fragments from 14 patients undergoing surgery for advanced destructive inflammatory joint disease. Eleven of the samples examined were from patients with classical rheumatoid arthritis, while three others were obtained from individuals with clinical osteoarthritis. Southern blot analysis of T-cell receptor (TCR) beta-chain genes in 13 of 14 cultures showed distinct rearrangements, indicating that each culture was characterized by the predominance of a limited number of clones. T-cell populations from peripheral blood stimulated with a variety of activators and expanded with IL-2 did not demonstrate evidence of similar clonality in long-term culture. These results suggest that a limited number of activated T-cell clones predominate at the site of tissue injury in rheumatoid synovial membranes as well as in other types of destructive inflammatory joint disease. Further characterization of these T-cell clones may aid our understanding of the pathogenesis of these rheumatic disorders.     

One systemic administration of transforming growth factor-beta 1 reverses age- or glucocorticoid-impaired wound healing.

The role of intravenously administered recombinant human transforming growth factor-beta 1 (rhTGF-beta 1) on the healing of incisional wounds in rats with impaired healing due to age or glucocorticoid administration was investigated. The administration of methylprednisolone to young adult rats decreased wound breaking strength to 50% of normal control. Breaking strength of incisional wounds from 19-mo-old rats was decreased approximately 27% compared with wounds from normal healing young adult rats. A single intravenous administration of rhTGF-beta 1 (100 or 500 micrograms/kg) increased wound breaking strength from old rats or young adult rats with glucocorticoid-induced impaired healing to levels similar to normal healing control animals when determined 7 d after injury. Even though the circulating half-life of systemically administered rhTGF-beta 1 is < 5 min, a sustained stimulatory effect on extracellular matrix secretion was evident in glucocorticoid-impaired rats when rhTGF-beta 1 was administered at the time of wounding, 4 h after wounding, or even 24 h before wounding. These observations indicate a previously unrecognized potential for the active form of TGF-beta 1 to profoundly influence the wound healing cascade after brief systemic exposure.     

Influences of gamma interferon on synovial fibroblast-like cells. Ia induction and inhibition of collagen synthesis

The shape and function of adherent cells cultured from rheumatoid synovial membranes are influenced by immune cells, and their products. The synovial cells produce collagenase and prostaglandin E2 (PGE2), the levels of which are increased when the cells are incubated with the monokine, mononuclear cell factor/interleukin 1. The majority of adherent synovial cells are fibroblastlike in appearance and synthesize collagens and fibronectin; the synthesis of collagens and fibronectins are also increased by a monocyte factor. In the present study we found that the fibroblastlike cells expressed major histocompatibility complex class II (Ia-like) antigens after initial dispersion from the synovial membrane. Monocyte lineage antigens were detected on some round cells in early passage, but no T lymphocytes were identified in established cultures. There was loss of Ia expression on the fibroblastlike cells with age and passage in culture. The addition of the lymphokine, gamma interferon (recombinant), induced class II antigen (DR and DS/DQ) expression in early or late passage cells in a time- and dose-dependent manner and required protein synthesis. Furthermore, the adherent synovial fibroblastlike cells continued to be Ia-positive when examined as long as 10 d after the removal of gamma interferon. Ia expression was also induced by gamma interferon in normal skin fibroblasts. Synovial cells that could be induced to express Ia also bound a monoclonal antibody to type III collagen (a fibroblast marker). Gamma interferon, while inducing Ia expression, decreased the binding of type III collagen antibody on unstimulated as well as monokine-stimulated cells. Analysis of [3H]proline-labeled medium by SDS polyacrylamide gel electrophoresis showed that gamma interferon decreased the synthesis of type I and III collagens and fibronectin by adherent synovial cells in a dose-dependent manner. These findings suggest that Ia expression by synovial tissue cells is not cell-specific, but reflects one or several related events, such as the degree of T lymphocyte infiltration, the presence of factors that stimulate gamma interferon release, or an increased sensitivity of the cells to gamma interferon. Whereas the synthesis of class II antigens is enhanced by the lymphokine gamma interferon, and a monocyte factor(s) stimulates collagen, collagenase and PGE2 synthesis by the same cells, gamma interferon inhibits basal and monokine-induced collagen synthesis. Thus, lymphokines and monokines may influence the extent of fibrosis as contrasted to matrix destruction at various stages of the rheumatoid lesion by affecting the function of fibroblastlike synovial cells.     

Mechanisms of drug-induced lupus. II. T cells overexpressing lymphocyte function-associated antigen 1 become autoreactive and cause a lupuslike disease in syngeneic mice.

Current theories propose that systemic lupus erythematosus develops when genetically predisposed individuals are exposed to certain environmental agents, although how these agents trigger lupus is uncertain. Some of these agents, such as procainamide, hydralazine, and UV-light inhibit T cell DNA methylation, increase lymphocyte function-associated antigen 1 (LFA-1) (CD11a/CD18) expression, and induce autoreactivity in vitro, and adoptive transfer of T cells that are made autoreactive by this mechanism causes a lupuslike disease. The mechanism by which these cells cause autoimmunity is unknown. In this report, we present evidence that LFA-1 overexpression is sufficient to induce autoimmunity. LFA-1 overexpression was induced on cloned murine Th2 cells by transfection, resulting in autoreactivity. Adoptive transfer of the transfected, autoreactive cells into syngeneic recipients caused a lupuslike disease with anti-DNA antibodies, an immune complex glomerulonephritis and pulmonary alveolitis, similar to that caused by cells treated with procainamide. These results indicate that agents or events which modify T cell DNA methylation may induce autoimmunity by causing T cell LFA-1 overexpression. Since T cells from patients with active lupus have hypomethylated DNA and overexpressed LFA-1, this mechanism could be important in the development of human autoimmunity.     

Specific high-affinity receptors for 1,25-dihydroxyvitamin D3 in human peripheral blood mononuclear cells: presence in monocytes and induction in T lymphocytes following activation

Human peripheral blood monocytes have high affinity binding sites for 1,25-(OH)2D3 (Kd 0.14 nM, sedimentation coefficient 3.7S). Resting human peripheral blood T lymphocytes, however, do not have a demonstrable 1,25-(OH)2D3 receptor. After activation with phytohemagglutinin the T cells exhibit the receptor within 24 h, and this expression is blocked by cycloheximide. The receptor in activated T lymphocytes has a sedimentation coefficient of 3.7S and a high affinity (Kd 0.10 nM) for the ligand.     

Treating activated CD4+ T cells with either of two distinct DNA methyltransferase inhibitors, 5-azacytidine or procainamide, is sufficient to cause a lupus-like disease in syngeneic mice.

Human antigen-specific CD4+ T cells become autoreactive after treatment with various DNA methylation inhibitors, including 5-azacytidine, procainamide, and hydralazine. This suggests a mechanism that could contribute to the development of some forms of autoimmunity. In this report we have asked whether T cells treated with DNA methylation inhibitors can induce autoimmunity. Murine CD4+ T cells were treated with 5-azacytidine or procainamide and were shown to respond to syngeneic antigen-presenting cells, similar to CD4+ human T cell clones treated with these drugs. Functional characterization demonstrated that cells treated with either drug spontaneously lysed syngeneic macrophages and secreted IL-4, IL-6, and IFN-gamma. Adoptive transfer of 5-azacytidine- or procainamide-treated cells into unirradiated syngeneic recipients induced an immune complex glomerulonephritis and IgG anti-DNA and antihistone antibodies. These experiments demonstrate that T cells treated with either of two distinct DNA methyltransferase inhibitors are sufficient to induce a lupus-like disease. It is possible that the lysis of macrophages, together with the release of cytokines promoting B cell differentiation, contributes to the autoantibody production and immune complex deposition. These results suggest that environmental agents that inhibit DNA methylation could interact with T cells in vivo to produce a lupus-like illness, a mechanism that could have relevance to drug-induced and idiopathic lupus.     

A controlled trial of intralesional recombinant interferon-gamma in the treatment of keloidal scarring. Clinical and histologic findings

Interferon-gamma (IFN-gamma) suppresses the synthesis of collagen by fibroblasts in vitro and the synthesis of collagen in vivo in animal models. Therefore, recombinant human IFN-gamma was examined for its ability to clinically modify keloids. Subjects were treated by injection of either 0.01 or 0.1 mg of recombinant human IFN-gamma into one lesional site and diluent alone into another lesional site three times per week for 3 weeks. Keloids were measured and photographed before beginning therapy and weekly thereafter. Three days after the final injection, biopsies were performed on treated and control sites. Six of eight subjects who finished the course of treatment demonstrated reduction in size at the treated site with an average reduction in height of 30.4% vs 1.1% for control sites. Lesions treated with recombinant human IFN-gamma demonstrated alterations in both the epidermis and dermis. The epidermis showed thinning of the suprapapillary plates, compact hyperkeratosis, focal or diffuse parakeratosis, exocytosis of lymphocytes, and an increased quantity of mucin. The dermis contained a diminished quantity of thickened collagen bundles and active fibroblasts and an increased number of inflammatory cells and quantity of mucin. These results suggest the feasibility of using IFN-gamma in the treatment of abnormal fibrosis. Dose-ranging studies are required to establish whether IFN-gamma can fulfill a true clinical need in the treatment of keloidal scarring.     

1,25-Dihydroxyvitamin D3 maintains adherence of human monocytes and protects them from thermal injury.

Adherence to a substratum is a characteristic feature of monocyte-macrophages which may be required for several effector functions. Human peripheral blood monocytes selected by adherence were found to readhere preferentially at 1 h to fibronectin or to a biological matrix. There was then a progressive decrease in the number of adherent cells, and by 48 h only 8-20% of monocytes remained adherent. This loss of adherence occurred while monocytes remained viable by criteria such as exclusion of trypan blue or release of lactate dehydrogenase. 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) maintained the adherence of cultured monocytes to tissue culture plastic as well as to the biological matrix. This effect was concentration- and time-dependent, and suppressed by inhibitors of protein synthesis. Cellular proteins were labeled after incubation with [35S]methionine. Analysis by two-dimensional gel electrophoresis revealed increased labeling of several distinct proteins in 1,25-(OH)2D3-treated monocytes compared with control monocytes. The increased loss of adherence and decreased overall protein synthesis observed in monocytes incubated at 45 degrees C was partially prevented by preincubation of the cells with 1,25-(OH)2D3. We further evaluated the effects of thermal stress and 1,25-(OH)2D3 on protein synthesis by monocytes, and found that 1,25-(OH)2D3 increased the synthesis of heat shock proteins, protected normal protein synthesis, and increased the rate of recovery of normal protein synthesis after the thermal stress. These observations suggest that 1,25-(OH)2D3 influences monocytes by preserving the synthesis of proteins, including those critical for the maintenance of cell adherence.