The side effects of Rapamycin was evaluated by histopathological examination of the heart, kidneys, and eyes of treated Lewis rats. Rapamycin was administered during 14 days by continuous intravenous infusions at doses of 0.5, 1.0, and 1.5 mg/kg/day. Focal myocardial infarction was observed in three of five rats with Rapamycin given at 1.5 mg/kg/day and two of 22 rats with 1.0 mg/kg/day. There were no sign of myocardial toxicity at a Rapamycin dose of 0.5 mg/kg/day. The retina of one eye of a rat treated at a dose of 1.5 mg/kg/day had a small area of focal ischemic necrosis. The kidneys were normal at all doses.

PURPOSE: To report metastatic Waldenström macroglobulinemia cells with immunoglobulin heavy chain gene rearrangement in the vitreous and the blood. METHODS: A 58-year-old man with Waldenström macroglobulinemia developed bilateral vitreitis. Diagnostic vitrectomy was performed on the left eye. The vitreous cells and the peripheral blood lymphocytes were analyzed using microdissection and polymerase chain reaction amplification. RESULTS: Vitrectomy specimen of the left eye contained a few degenerated cells. Molecular analysis showed immunoglobulin heavy chain gene rearrangement at the third complementary determining region of the vitreal infiltrating cells and peripheral blood lymphocytes. CONCLUSIONS: Waldenström macroglobulinemia rarely metastasizes to the vitreous. Molecular detection of the immunoglobulin heavy chain gene third complementary determining region rearrangement is helpful in the diagnosis of the malignancy. Microdissection combined with polymerase chain reaction is a useful and innovative tool for molecular pathological investigation.

To the Editor: Two herpesviruses, human herpesvirus-8 (HHV-8) and Epstein-Barr virus (EBV), are able to contribute to lymphomagenesis in humans.[1][1] HHV-8 is documented not only in a strong association with Kaposi’s sarcoma, but also in a high percentage of primary effusion lymphoma, Castleman

AIM:To evaluate the anti-inflammatory cytokine interleukin-13 (IL-13) for the treatment of uveitis. METHODS:Uveitis was induced in monkeys by immunisation with human retinal S-antigen. Starting at the onset of disease, the animals were treated with IL-13 at 25 micrograms/kg, or vehicle control, injected subcutaneously once a day for 28 days. Intraocular inflammation was scored by indirect ophthalmoscopy for a period of 56 days. Circulating leucocyte levels were monitored. RESULTS:Uveitis started unilaterally in all but one animal. IL-13 inhibited inflammation both in the eyes in which the disease was present when the treatment was initiated (p = 0.0001), and in the contralateral initially negative eyes (p = 0.0001). After cessation of therapy, there was a progressive increase of inflammation in the IL-13 treated group. However, the beneficial effect of IL-13 extended into the 4 week follow up period. IL-13 produced an increase in circulating polymorphonuclear neutrophils and a decrease in lymphocytes. CONCLUSION:Administration of IL-13 appears to be a promising modality of treatment for severe uveitis.

We studied the efficacy and tolerance of humanized Ab interfering with the signal of the IL-2 and IL-15 receptors in a primate model of experimental autoimmune uveoretinitis. The inhibitory effects of humanized anti-Tac (HAT), an anti-IL-2R alpha-chain Ab, and HuMik beta1, an Ab directed at the beta-chain shared by the receptors of IL-2 and IL-15, were tested in culture on the proliferative response of monkey Con A-blast lymphocytes stimulated with IL-2 or IL-15. Uveitis was induced in cynomolgus monkeys by immunization with human recombinant retinal S-antigen. Treatment was initiated at the first sign of disease and consisted of HAT and HuMik beta1, alone or in combination, or vehicle control given by i.v. injection twice a week for 4 wk. Disease was evaluated by ocular funduscopy. The results in culture showed a significant dose-dependent inhibition of the IL-2-driven proliferation of lymphocytes by HAT. HuMik beta1 alone was ineffective against IL-2 stimulation, but had a marked potentiating effect in combination with HAT, independent of IL-15 signaling. IL-15-driven proliferation was inhibited by HuMik beta1, but not by HAT alone or in combination. In monkeys, experimental autoimmune uveoretinitis evolution was significantly inhibited by HAT treatment. HuMik beta1 alone had no effect on the disease. However, when used in combination, the two Ab markedly reduced the severity of ocular inflammation. The Ab were well tolerated. Only three monkeys, treated with HAT alone, made an Ab response against the injected Ab.

PURPOSETransforming growth factor beta-1 (TGF beta-1) can modulate inflammation. Endotoxin-induced uveitis (EIU) is characterized by acute ocular inflammation related to the release of cytokines, including interleukin (IL)-6. The authors investigated the effect of TGF beta-1 on EIU in mice.METHODSThree independent experiments were performed. Endotoxin-induced uveitis was induced in C3H/HeN mice by an injection of 200 micrograms of lipopolysaccharide (LPS). Two micrograms of TGF beta-1 in 0.1 ml phosphate-buffered saline (PBS) or 0.1 ml PBS alone was administered intraperitoneally at 8 hours after LPS injection. Twenty-four hours after LPS injection, the aqueous humor of the right eyes was collected for leukocyte count, protein concentration, and IL-6 assay. Left eyes were processed for routine histology.RESULTSTGF beta-1-treated mice showed less ocular inflammation histologically than to the animals that were given PBS. This was confirmed by decreases in leukocyte count, protein concentration, and IL-6 level in the aqueous humor.CONCLUSIONSTGF beta-1 inhibits the development of EIU. TGF beta-1 may be useful for the modulation of uveitis in humans.

AIMS:To evaluate the role of nitric oxide (NO) in ocular involvement during systemic toxoplasmosis.METHODS:C57B1/6 mice were infected with Toxoplasma gondii strain ME49. The synthesis of NO was inhibited by an intraperitoneal injection of aminoguanidine every 8 hours, starting on the day of infection. Control infected mice received phosphate buffered saline vehicle alone. After 14 days, the ocular lesions were evaluated by histopathological examination. The expression of NO synthase induced in the spleen by toxoplasma infection was evaluated by immunostaining. The production of NO by the spleen cells of infected mice was measured by the colorimetric assay of Griess in the supernatant of cultures stimulated with toxoplasma antigen or concanavalin A.RESULTS:The inhibition of NO production in T gondii infected mice resulted in a marked increase in the symptoms of ocular inflammation. We observed a strong induction of NO synthase expression in the spleen of infected animals. In culture, the spleen cells from these mice produced high levels of NO in response to T gondii antigens. This elevation of NO synthesis was suppressed in the presence of aminoguanidine.CONCLUSION:This study indicates that NO plays a crucial role in the protection against T gondii infection as reflected by the severity of the ocular involvement.

We studied the effect of nitric oxide (NO) production on the evolution of toxoplasmosis in C57BL/6 mice. Infection was induced by i.p. injection of Toxoplasma gondii strain ME49. NO synthesis was inhibited by treatment with aminoguanidine, a structural analogue of L-arginine. The severity of infection was evaluated by histopathologic examination of the brain. In the infected mice treated for 2 wk with aminoguanidine, we observed an increase in the number of toxoplasma tachyzoites and intracellular cysts accompanied by an exacerbated inflammation of the brain tissue compared with that in controls. When spleen cells from infected mice were stimulated in culture with toxoplasma Ag, there was a marked cytotoxic effect on cells collected during the acute stage of infection and an inhibition of proliferation of the remaining viable lymphocytes. These effects were correlated with high levels of NO and PGE2 production. The suppression of NO synthesis prevented cell death and restored the lymphocyte proliferative response as well as lymphokine production. The neutralization of IFN-gamma or TNF-alpha had no effect on NO production in the cultures of infected mouse spleen cells. Cultures in which purified macrophages and lymphocytes from infected and naive mice were mixed indicated that the production of NO was dependent on lymphocyte activation. In the later stages of infection, when the production of NO was abating, preventing PGE2 secretion with indomethacin also increased the lymphocyte proliferative response. We conclude that the opposing effects of NO in toxoplasmosis, which protects against Toxoplasma gondii and at the same time limits the immune response, probably contribute to the establishment of the characteristic chronic state of host parasite equilibrium.

AIMS/BACKGROUND: The subcutaneous injection of bacterial endotoxin in Lewis rats produces an acute intraocular inflammation evolving over a 24 hour period. This endotoxin induced uveitis (EIU) is characterised by a biphasic protein exudation and a cellular infiltrate composed of macrophages and polymorphonuclear neutrophils (PMNs). This model was used to study the mechanism of cellular infiltration in ocular inflammation. METHODS: EIU was induced by a subcutaneous injection of lipopolysaccharide (LPS) (S typhimurium) at 350 micrograms/kg. The levels of cytokine induced neutrophil chemoattractant (CINC) were measured every 2 hours in the serum and in the aqueous humour by ELISA. The intraocular inflammation was quantified by protein measurement and leucocyte counting. RESULTS: The kinetics of CINC production in the systemic circulation showed a rapid rise, peaking 2 hours after LPS injection, followed by a progressive decline over the next 8 hours. In the eye, the CINC levels increased above the serum levels 10 hours after EIU induction corresponding to the time of cellular infiltration. When leucocyte entry in the eye was inhibited by 56% and 64% with an antiadhesion molecule antibody, there was only a slight reduction in the aqueous humour CINC levels of 9% and 16%, respectively, indicating that CINC was produced by ocular tissue cells. The specific effect of CINC in the eye was confirmed when a direct intraocular injection of 250 ng of purified CINC was followed by significant PMN infiltration, in the absence of protein exudation. CONCLUSION: The data indicate that the production of the CINC chemotactic factor by ocular tissue participates in the inflammatory reaction in EIU.

The authors studied the combination effect of corticosteroids with the new immunosuppressant Rapamycin for the treatment of intraocular inflammation. A median-effect analysis, of the combined effect of Rapamycin and dexamethasone, was performed on the inhibition of lymphocyte proliferation in culture. The mathematical formulas allowed for the calculation of combination indices and dose-reduction factors. On the basis of these in-vitro results, treatment with reduced doses of drugs in combination was evaluated in the rat model of experimental autoimmune uveoretinitis. The results showed that Rapamycin and dexamethasone were synergistic over a wide concentration range. The calculated dose reduction factors indicated that an equivalent inhibition of lymphocyte proliferation was achieved with a combination of Rapamycin and dexamethasone reduced by 5-7 and 3-6 fold respectively, compared to the concentration required when each drug was used alone. In animals, there was a significant reduction of the incidence and severity of ocular inflammation with low doses of the drugs in combination. The authors conclude that the observed synergistic effect between Rapamycin and dexamethasone suggests that the use of this drug combination might be advantageous in the treatment of patients with severe uveitis.

Objective: To examine the relationship between visual outcome and the clinical management of patients with sympathetic ophthalmia.Methods: Thirty-two patients with sympathetic ophthalmia who were seen at the National Eye Institute, Bethesda, Md, between 1982 and 1992, were retrospectively reviewed.Results: There were equal numbers of males and females. Sympathetic ophthalmia occurred after trauma in 23 patients and surgery in nine patients. Sixteen of the 32 patients had a final visual acuity of 20/40 or better; 10 patients had a visual acuity worse than 20/200. Good visual outcome was associated with early and aggressive treatment with corticosteroids, sometimes in combination with other immunosuppressive agents. Poor visual acuity was associated with glaucoma, chorioretinal scars in the macula, and persistent uncontrolled inflammation.Conclusion: Prompt and aggressive use of antiinflammatory therapy can improve the visual outcome of patients with sympathetic ophthalmia.

OBJECTIVE:To evaluate the possible role played by nitric oxide in the pathogenesis of uveitis.METHODS:Uveitis was induced in rats with subcutaneous lipopolysaccharide. Lipopolysaccharide stimulates nitric oxide production from L-arginine. The animals were treated with NG-nitro-L-arginine methyl ester, an L-arginine analogue acting as a specific inhibitor of nitric oxide synthesis. Ocular inflammation was evaluated by measuring protein concentration and leukocyte number in the aqueous humor of one eye, and by histopathologic examination of the contralateral eye.RESULTS:Aqueous humor protein levels were reduced 73% to 82% and cellular infiltration was almost abrogated in NG-nitro-L-arginine methyl ester-treated rats compared with controls. The histopathologic examination also showed a similar inhibition of uveal tissue inflammation in treated rats.CONCLUSION:By inhibiting nitric oxide synthesis, NG-nitro-L-arginine methyl ester inhibits the induction of endotoxin-induced uveitis in the rat. This observation demonstrates that nitric oxide is an important mediator of anterior uveitis in this model system and suggests that nitric oxide may also be implicated in human uveitis.