Graves' disease in HTLV-I carriers.

Three carriers of human T-lymphotropic virus type I (HTLV-I) with Graves' disease are reported. All three cases were complicated with uveitis, and one also showed chronic arthropathy. Anti-HLTV-I antibody was found in the serum by the particle agglutination method and western blotting, and HTLV-I proviral DNA was detected in peripheral lymphocytes by the polymerase chain reaction and Southern blotting. HTLV-I is a causal agent of adult T-cell leukemia and HTLV-I associated myelopathy/tropical spastic paraparesis, and is believed to be related to the pathogenesis of diseases such as chronic arthropathy, uveitis, chronic bronchoalveolitis, and Sjögren's syndrome. On the other hand, retrovirus infection is considered to cause autoimmune diseases. Thus, the pathogenesis of Graves' disease in the present patients might be associated with HTLV-I infection.

Endotoxin-induced uveitis in mice. 1. Induction of uveitis and role of T lymphocytes.

Endotoxin-induced uveitis (EIU) with a high frequency of posterior iris synechiae was induced by the systemic injection of 200 micrograms of endotoxin into C3H/HeN mice, an endotoxin-responsive strain. The cell number and the protein concentration within the aqueous humor began to increase 6 hours after the injection, achieving a peak at 24 hours, and decreased gradually thereafter. Inflammatory cells were observed in the anterior chamber, the vitreous body and near the iris-ciliary body histologically. Most of the inflammatory cells were polymorphonuclear cells. On the other hand, C3H/HeJ mice, an endotoxin-unresponsive strain, showed no increase in either cell number or protein concentration in the aqueous humor after endotoxin administration. Pretreatment of C3H/HeN mice with anti-Thy-1.2 antibody significantly decreased both the cell number and the protein concentration in the aqueous humor and the incidence of the posterior synechiae, as compared with the control group. Anti-CD4 antibody also significantly reduced the severity of EIU, while anti-CD8 antibody had no influence on the disease. Anti-IFN-gamma antibody increased the cell number in the aqueous humor. These observations indicate that T lymphocytes, especially CD4+ T lymphocytes, have an extremely important role in the development of EIU in mice.

Characterization of T-cell subsets, soluble interleukin-2 receptors and interleukin-6 in Vogt-Koyanagi-Harada disease.

The lymphocyte subunits and subsets of 12 patients with Vogt-Koyanagi-Harada disease (VKH disease) were characterized using two-color flow cytometry techniques, both in cerebrospinal fluid (CSF) and in peripheral blood (PB). Soluble interleukin-2 receptor (sIL-2R) levels and interleukin-6 (IL-6) levels were also measured. The percentage of T cells was significantly higher in CSF than in PB (P less than 0.01), but the percentage of B cells was decreased in CSF (P less than 0.05). As for T-cell subsets, the percentage of helper T cells was especially high in CSF (P less than 0.01). Also, the ratio of helper T cells/suppressor T cells was significantly larger in CSF than in PB. These data suggest that helper T cells play an important role in the early stages of VKH disease. sIL-2R and IL-6 levels were not elevated in CSF of patients with VKH disease. The level of sIL-2R in serum also was not elevated.

[Endogenous uveitis in disseminated intravascular coagulation induced by endotoxin].

A study was made of endogenous uveitis in experimental disseminated intravascular coagulation (DIC) in rabbits. Endotoxin was injected intravenously twice with a 24-hour interval. The time courses of the following were examined: 1) aqueous flare using a laser flare-cell meter 2) the number of leukocytes in the peripheral blood 3) the tumor necrosis factor (TNF) activity in the serum and 4) histopathological changes in the eye, lung, liver and kidney. Aqueous flare increased at 1 hour and was maximal at 6 hours, accompanied by a rapid increase in TNF activity at 1 hour following the first endotoxin administration. The number of leukocytes decreased to 963 +/- 266 cells/mm3 at 1.5 hours with subsequent leukocytosis within 12 hours. After the second injection of endotoxin, the aqueous flare peaked in 30 minutes and was twice as high as the first peak. Leukocyte number and TNF activity showed the same behavior. However, TNF activity was 20% that of the first peak. Histopathological examination indicated fibrin formation in the small vessels of systemic organs within 3 hours following the second administration of endotoxin. Endotoxin induced uveitis was induced in experimental DIC, and leukocytes and TNF activity may thus perform important roles.

Production of prostaglandin E2 rather than E1 in experimental ocular inflammation of rabbit.

The chopped anterior uvea of rabbit was allowed to react with exogenous [1-14C] arachidonic acid or prostaglandin (PG)H2. Several cyclooxygenase products such as PGD2, PGE2 and PGF2 alpha were produced. In the presence of glutathione PGE2 was a major product. When uveitis was induced by injection of bovine serum albumin into the vitreous body, there was a marked invasion of leukocytes. PGE2 in the aqueous humor increased about 3-fold as determined by radioimmunoassay using anti-PGE2 antibody cross-reacting with PGE1. Extracts from the inflamed aqueous humor and the incubation medium of chopped anterior uvea or peripheral polymorphonuclear leukocytes were analyzed by reverse-phase high-performance liquid chromatography, which allowed separation of PGE2 and PGE1. In all these preparations PGE2 was an almost sole immunoreactive PG, and PGE1 was hardly detectable in sharp contrast to an earlier report (Eakins et al.: Nature 239: 248 (1972].

[The dynamics of leucocytes and complements in endotoxin induced uveitis].

The dynamics of leukocytes, complement and tumor necrosis factor (TNF) were studied in endotoxin induced uveitis (EIU) in rats. Endotoxin was administered to footpads and the time courses of the following were examined: 1) the number of leukocytes in peripheral blood 2) the number of leukocytes and protein concentration of aqueous humor 3) complement (CH50, C1, C3, C5) in serum and aqueous humor 4) TNF in serum 5) histological changes in the eyes, lungs, liver, and skin. The number of leukocytes in peripheral blood decreased to one third that of controls during three to six hours after endotoxin administration, but increased thereafter along with the number of leukocytes and protein concentration in aqueous humor. More leukocytes were observed than in controls in the small vessels of the iris, lung, liver and skin, some of which attached to the vascular endothelium. Serum C3 increased and serum C5 transiently decreased after endotoxin administration. Serum TNF reached a peak (3500 IU/ml) at 1.5 hours and rapidly decreased subsequently. It is suggested that the adhesion of leukocytes to vascular endothelium and the activation of complement system may play important roles in the development of EIU.

Tetranactin, a macrotetrolide antibiotic, suppresses in vitro proliferation of human lymphocytes and generation of cytotoxicity.

Tetranactin, a hydrophobic cyclic antibiotic produced by Streptomyces aureus, has previously been shown to suppress in vitro activation of rat lymphocytes by concanavalin A as well as the onset of experimental autoimmune uveoretinitis in Lewis rats. Here we report the effects of tetranactin on human T and NK lymphocytes in vitro. Tetranactin, at concentrations up to 100 ng/ml, was not toxic to human lymphocytes but completely abrogated the proliferation of human T lymphocytes in response to allogeneic cells in mixed lymphocyte cultures. Tetranactin also blocked the initiation of proliferation in response to interleukin-2, but did not block proliferation of interleukin-2-activated cells. Tetranactin also blocked generation of cytotoxic T lymphocytes and activated killer cells in the mixed lymphocyte culture. However, up to 100 ng/ml tetranactin did not alter the lytic activity of cytotoxic T or NK lymphocytes generated in its absence. The ability of low doses of tetranactin to block the induction of lymphoproliferation is similar to the action of cyclosporin A. Since cyclosporin A is also a cyclic hydrophobic molecule, the immunosuppressive actions of these two agents may involve a similar mechanism.

Immunosuppressive and anti-proliferative effects of a macrotetrolide antibiotic, tetranactin.

The macrotetrolide tetranactin suppressed the appearance of experimental autoimmune uveoretinitis induced in Lewis rats with a soluble retinal antigen (S-antigen). The drug at 1 ng/ml inhibited the mitogen activation of unfractionated lymphocytes; incorporation of radiolabelled precursors such as thymidine, uridine and leucine into the cells was markedly reduced. The synthesis and release of IL-2 by mitogen-activated lymphocytes was significantly suppressed in the presence of tetranactin. Incorporation of 45Ca was also inhibited, while intracellular Na+ levels were increased. In view of the ionophore property of tetranactin, it was suggested that the drug might demonstrate its immunosuppressive effect by affecting intracellular cation concentrations.

Immunosuppressive effects of polynactins (tetranactin, trinactin and dinactin) on experimental autoimmune uveoretinitis in rats.

Macrotetrolide antibiotic polynactins [dinactin, trinactin and tetranactin (1:4:5)] are hydrophobic cyclic esters produced by Streptomyces aureus. Polynactins (PN) and their major component tetranactin (TN) delayed or suppressed the onset of S-antigen-induced experimental autoimmune uveoretinitis (EAU) in Lewis rats. Termination of treatment with PN or TN before day 14 of immunization resulted in a delayed onset of EAU in many animals. Thus, the immunosuppressive effect of PN and TN was not lasting. PN and TN suppressed anti-S-antigen antibody formation. Skin hypersensitivity tests indicated suppression by PN of the delayed-type rather than Arthus type hypersensitivity to S-antigen. PN, TN and trinactin all inhibited 3H-thymidine incorporation into concanavalin A-treated lymphocytes at the early stage of cell activation. For each drug, 50% inhibition was obtained at about 0.1 ng/ml. Under the incubation condition that the cells were exposed to TN for 21 hours, cell viability remained unchanged up to 100 ng/ml of TN. It is evident that PN and TN suppress T-lymphocyte proliferation without cell injury. These results suggest that PN and TN inhibit the onset of EAU primarily through the suppression of cell-mediated immunity but also by affecting humoral immunity.

Superoxide in ocular inflammation: human and experimental uveitis.

A possible involvement of superoxide in the pathogenesis of uveal inflammation in man and experimental animals was investigated. Superoxide production by the leukocytes of Behcet patients was significantly higher in the attack phase than in the remission phase. Leukocyte superoxide generation was also enhanced in guinea pigs with S-antigen-induced experimental autoimmune uveoretinitis (EAU). If the animals were treated with superoxide dismutase (SOD) at the onset of EAU, aqueous humor cell count was significantly lower than that of control (i.e., without SOD treatment). Infiltration of the inflammatory cells in the anterior retina was markedly reduced in SOD-treated animals. A similar protective effect of SOD against tissue damage was also observed in a bovine serum albumin-induced passive Arthus type uveitis in rabbits. These results suggest that superoxide may play a role in causing tissue damage in animal models of ocular inflammation and possibly in Behcet disease.