De Fen Shen

Utility of microdissection and polymerase chain reaction for the detection of immunoglobulin gene rearrangement and translocation in primary intraocular lymphoma

OBJECTIVEnPrimary intraocular lymphoma, a non-Hodgkins lymphoma, is a primary central nervous system lymphoma (PCNSL). Diagnosis is usually made by identifying malignant, large B lymphocytes in the vitreous, eye, brain, and cerebral spinal fluid; however, these cells are few, friable, and difficult to recognize. Recently, clonal heavy chain immunoglobulin (IgH) gene rearrangement and bcl-2 gene translocation have been reported in systemic B-cell lymphoma and are used for the detection of malignant cells and in making a diagnosis. The authors investigated the molecular changes in three eyes and a chorioretinal biopsy specimen of four patients with PCNSL.nnnDESIGNnHuman tissue study.nnnMATERIALSnFive ocular specimens of PCNSL were collected.nnnINTERVENTIONnThe first patient had a diagnostic enucleation of the left eye. The second patient underwent diagnostic chorioretinal biopsy. In the third case, a pair of autopsied eyes with reactive lymphoplasmacytic infiltrates of a patient with acquired immune deficiency syndrome (AIDS) were studied. In the fourth case, an enucleated eye of a patient with AIDS-associated lymphoma was sampled.nnnMAIN OUTCOME MEASURESnThe bcl-2 and IgH genes of the lymphoma cells from routine, paraffin-embedded, formaldehyde-fixed, or frozen histologic tissue sections were analyzed using microdissection and polymerase chain reaction (PCR) technique.nnnRESULTSnLymphoma cells obtained from the above four cases showed IgH rearrangement gene in the third framework of the VH region. Bcl-2-associated translocation also was detected in three cases (cases 1, 2, and 4).nnnCONCLUSIONnRearrangement of the IgH gene can serve as a molecular marker for PCNSL. Microdissection allows for procurement and analysis of specific, selected, minute cell populations that are obtained from histologic sections of the complex, heterogeneous tissue. Translocation of IgH and bcl-2, the apoptotic survival signal and proto-oncogene, could contribute to the pathogenesis of PCNSL. The combination of microdissection and PCR is a powerful tool for studies of small lesions and cell populations and for understanding disease mechanisms.

Detection of Toxoplasma Gondii DNA in Primary Intraocular B-Cell Lymphoma

Primary intraocular lymphoma, a variant of primary central nervous system lymphoma with ocular involvement, is a large B-cell non-Hodgkins lymphoma. Some cases of primary intraocular lymphoma have been reported to be associated with microorganisms including Epstein-Barr virus (EBV) and human herpes virus-8 (HHV-8), but not parasites. We analyzed 10 cases of primary intraocular lymphoma using microdissection and PCR. Tumor and normal cells were microdissected from ocular tissue on slides and subjected to PCR for genes from Toxoplasma gondii, EBV, and HHV-8. We detected Toxoplasma gondii, not HHV-8 or EBV, DNA in the lymphoma but not in normal cells of two cases that resembled ocular toxoplasmosis clinically. We speculate that Toxoplasma gondii may play a role in some forms of primary intraocular B-cell lymphoma.

Effect of sex hormones on experimental autoimmune uveoretinitis (EAU).

Purpose: Sex hormones have been associated with the prevalence, susceptibility, and severity of autoimmune disease. Although the exact mechanism is unknown, sex hormones are reported to influence cytokine production, specifically by affecting the balance of Th1 and Th2 effector cells. We evaluated the effect of estrogen, progesterone, and testosterone in autoimmune uveoretinitis (EAU), a rodent model of human ocular autoimmune disease. Methods: Lewis rats implanted with either β‐estradiol (estrogen), 5‐dihydrotestosterone (5‐DHT), norgestrel (progesterone), or estrogen plus progesterone were immunized with the retinal antigen interphotoreceptor retinoid binding protein (IRBP) peptide. Evaluation of EAU was based on histology of the eyes and measurement of peripheral immunological responses of DTH and lymphocyte proliferation to S‐antigen. Quantitative RT‐PCR was used to measure IFN‐γ and IL‐10 mRNA in the eyes. Results: In female rats 5‐DHT significantly decreased, estrogen slightly enhanced, but progesterone or estrogen + progesterone did not affect EAU. In contrast, in male rats 5‐DHT slightly decreased, estrogen moderately decreased, progesterone did not effect, but, estrogen + progesterone slightly decreased EAU. The results correlated with the ocular levels of Th1 (IFN‐γ) and Th2 (IL‐10) cytokine messengers. Conclusion: The data support the hypothesis that sex hormones may affect autoimmune diseases by inducing changes in the cytokine balance. This suggests that sex hormone therapy could be considered as an adjunct to anti‐inflammatory agents to treat ocular autoimmune diseases in humans.

Eradication of Tumor Colonization and Invasion by a B Cell–Specific Immunotoxin in a Murine Model for Human Primary Intraocular Lymphoma

Human primary intraocular lymphoma (PIOL) is predominantly a B cell-originated malignant disease with no appropriate animal models and effective therapies available. This study aimed to establish a mouse model to closely mimic human B-cell PIOL and to test the therapeutic potential of a recently developed immunotoxin targeting human B-cell lymphomas. Human B-cell lymphoma cells were intravitreally injected into severe combined immunodeficient mice. The resemblance of this tumor model to human PIOL was examined by fundoscopy, histopathology, immunohistochemistry, and evaluated for molecular markers. The therapeutic effectiveness of immunotoxin HA22 was tested by injecting the drug intravitreally. Results showed that the murine model resembles human PIOL closely. Pathologic examination revealed that the tumor cells initially colonized on the retinal surface, followed by infiltrating through the retinal layers, expanding preferentially in the subretinal space, and eventually penetrating through the retinal pigment epithelium into the choroid. Several putative molecular markers for human PIOL were expressed in vivo in this model. Tumor metastasis into the central nervous system was also observed. A single intravitreal injection of immunotoxin HA22 after the establishment of the PIOL resulted in complete regression of the tumor. This is the first report of a murine model that closely mimics human B-cell PIOL. This model may be a valuable tool in understanding the molecular pathogenesis of human PIOL and for the evaluation of new therapeutic approaches. The results of B cell-specific immunotoxin therapy may have clinical implications in treating human PIOL.

Cytokine gene expression in different strains of mice with endotoxin-induced uveitis (EIU).

PURPOSE: The kinetics of various cytokines in the eye plays a critical role in endotoxin-induced uveitis (EIU). This study examined the cytokine kinetics and susceptibility of EIU in four mice strains. METHODS: Four strains of TLR-4 or Toll-like receptor-4 (Lps, lipopolysaccharide-susceptible) gene-positive mice (C3H/HeN of H-2 k , C57/B6 of H-2 b , Balb/C of H-2 d , and 129/J of H-2 b ) were injected subcutaneously with either lipopolysaccharide (LPS) in phosphate-buffered saline (PBS) or PBS alone in two repeated experiments. Mice were sacrificed 1, 3, 6, 24 (1 d), 72 (3 d), 120 (5 d), or 168 (7 d) hours after LPS injection. Ocular histology and reverse transcriptase-polymerase chain reaction (RT-PCR) to detect ocular interleukin-1a (IL-1a), IL-6, tumor necrosis factor-a (TNF-a), and granulocyte-macrophage colony-stimulating factor (GM-CSF) mRNA were performed. Serum IL-1a, IL-1ß, IL-6, and TNF-a levels were measured using enzyme-linked immunosorbent assay (ELISA). RESULTS: No ocular inflammation was present in any mice within six hours after LPS injection. Only the C3H/HeN mice developed a biphasic ocular inflammatory response (1 d and 5 d), during which all proinflammatory cytokine messages were expressed. In the other three strains with minimal (129/J and Balb/C) to mild (C57/B6) EIU that peaked at 1 d, IL-6 mRNA was barely detectable in C57/B6 and Balb/C; GM-CSF mRNA was also present in C57/B6. Serum IL-1a, IL-1ß, IL-6, and TNF-a were high in all EIU mice within six hours after LPS injection. Control mice did not develop uveitis or measurable cytokine messages. CONCLUSION: In the most susceptible strain, C3H/HeN, EIU was biphasic and correlated to multiple proinflammatory cytokines released in the eye. The less susceptible mice strains exhibited a monophasic response to LPS that may result from no cytokine cascade.

Rearrangement of immunoglobulin gene in metastatic Waldenström macroglobulinemia to the vitreous.

PURPOSEnTo report metastatic Waldenström macroglobulinemia cells with immunoglobulin heavy chain gene rearrangement in the vitreous and the blood.nnnMETHODSnA 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.nnnRESULTSnVitrectomy 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.nnnCONCLUSIONSnWaldenström 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.

Suppressor of Cytokine Signaling 1 (SOCS1) Mitigates Anterior Uveitis and Confers Protection Against Ocular HSV-1 Infection

Immunological responses to pathogens are stringently regulated in the eye to prevent excessive inflammation that damage ocular tissues and compromise vision. Suppressors of cytokine signaling (SOCS) regulate intensity/duration of inflammatory responses. We have used SOCS1-deficient mice and retina-specific SOCS1 transgenic rats to investigate roles of SOCS1 in ocular herpes simplex virus (HSV-1) infection and non-infectious uveitis. We also genetically engineered cell-penetrating SOCS proteins (membrane-translocating sequence (MTS)-SOCS1, MTS-SOCS3) and examined whether they can be used to inhibit inflammatory cytokines. Overexpression of SOCS1 in transgenic rat eyes attenuated ocular HSV-1 infection while SOCS1-deficient mice developed severe non-infectious anterior uveitis, suggesting that SOCS1 may contribute to mechanism of ocular immune privilege by regulating trafficking of inflammatory cells into ocular tissues. Furthermore, MTS-SOCS1 inhibited IFN-γ-induced signal transducers and activators of transcription 1 (STAT1) activation by macrophages while MTS-SOCS3 suppressed expansion of pathogenic Th17 cells that mediate uveitis, indicating that MTS-SOCS proteins maybe used to treat ocular inflammatory diseases of infectious or autoimmune etiology.