Clinical and immunohistochemical correlation of herpetic keratitis with the expression of HLA-DR antigen

The outcome of corneal grafting in patients with stromal keratitis of herpetic and non-herpetic origin

AIM

To evaluate the outcome of corneal grafting in patients with stromal keratitis of herpetic (HSK) and non-herpetic origin, using predefined diagnostic criteria and standardised postoperative therapeutic strategies.

METHODS

384 adult immunocompetent recipients of a corneal graft for herpetic (n = 186) or non-herpetic (n = 198) keratitis were followed up prospectively for up to 5 years.

RESULTS

The herpetic group displayed significantly more corneal vascularisation (p = 0.013), more epithelial defects (p = 0.049), lower corneal sensitivity (p <0.001), more graft rejection episodes (p = 0.002), and required larger grafts (p<0.001). However, the postoperative course of visual acuity, endothelial cell numerical density, and rate of graft failures were similar in both groups. After 5 years, cumulative probability of graft survival in HSK patients (40.85%) was similar to that observed in individuals with non-herpetic keratitis (50.15%; log rank = 0.874; relative risk: 1.04).

CONCLUSION

Despite a markedly higher preoperative risk profile in herpetic eyes, the functional outcomes of grafts in individuals with keratitis of herpetic or non-herpetic origin were similar. Probably the most important contribution is a consequent close follow up and a therapeutic strategy including systemic prophylaxis of viral recurrence and of graft rejection by well adopted local steroid therapy.

MMP-9 is predominantly expressed in epithelioid and not spindle cell uveal melanoma

Extracellular matrix-degrading enzymes are crucial for cancer metastases. One group of enzymes that has been increasingly implicated in the breakdown of the extracellular matrix, and hence the intravasation and dissemination of tumour cells, is the family of metalloproteinases. In the recent past, increasing efforts have led to the development of more or less specific matrix metalloproteinase (MMP) inhibitors. Data concerning the molecular nature and timing of the contribution of MMPs to tumour spread is of paramount importance in clarifying which MMP is an appropriate target for more selective MMP inhibition in future tumour therapy. This study immunohistochemically characterized the expression pattern of MMP-2, -3, and -9 in 26 uveal melanomas. Forty-six per cent of the uveal melanomas expressed MMP-2 and/or MMP-9. MMP-3 expression was seen in 17 out of 26 uveal melanomas. MMP-9, previously shown to play an important part in tumour dissemination, was predominantly present in epithelioid melanomas (71.4%) or the epithelioid portion of mixed cell uveal melanomas (67%), whereas only one out of ten spindle cell melanomas showed MMP-9 expression (10%). MMP-2 and MMP-9 expression was associated with a significantly higher incidence of metastatic disease. The survival rate of patients with MMP-2-positive melanomas was 31% vs. 85% for patients with MMP-2-negative (p<0.05); for MMP-9-positive uveal melanomas the survival rate was 27% vs. 85% with MMP-9-negative uveal melanomas (p<0.04). The fact that patients suffering from TIMP-1- as well as TIMP-2-positive uveal melanomas tended to show a better survival rate (72% vs. 45% for TIMP-1; 88% vs. 37% for TIMP-2) supports the view that proteolytic enzymes are of importance in tumour spread.

Tegument-specific, virus-reactive CD4 T cells localize to the cornea in herpes simplex virus interstitial keratitis in humans

Herpes stromal keratitis (HSK) is a prevalent and frequently vision-threatening disease associated with herpes simplex virus type 1 (HSV-1) infection. In mice, HSK progression occurs after viral clearance and requires T cells and neutrophils. One model implicates Th1-like CD4 T cells with cross-reactivity between the HSV-1 protein UL6 and a corneal autoantigen. HSK can be prevented by establishing specific immunological tolerance. However, HSK can also occur in T-cell receptor-transgenic X SCID mice lacking HSV-specific T cells. To study the pathogenesis of HSK in the natural host species, we measured local HSV-specific T-cell responses in HSK corneas removed at transplant surgery (n = 5) or control corneas (n = 2). HSV-1 DNA was detected by PCR in two specimens. HSV-specific CD4 T cells were enriched in three of the five HSK specimens and were not detectable in the control specimens. Reactivity with peptide epitopes within the tegument proteins UL21 and UL49 was documented. Responses to HSV-1 UL6 were not detected. Diverse HLA DR and DP alleles restricted these local responses. Most clones secreted gamma interferon, but not interleukin-5, in response to antigen. HSV-specific CD8 cells were also recovered. Some clones had cytotoxic-T-lymphocyte activity. The diverse specificities and HLA-restricting alleles of local virus-specific T cells in HSK are consistent with their contribution to HSK by a proinflammatory effect.

Synthesis pattern of matrix metalloproteinases (MMPs) and inhibitors (TIMPs) in human explant organ cultures after treatment with latanoprost and dexamethasone

PURPOSE

To determine changes in production of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) in the ciliary body, the trabecular meshwork and the retinal pigment epithelium induced by both prostaglandins and corticosteroids.

METHODS

Explant organ cultures were removed by a scleral incision 3 mm posterior to the limbus. Retinal pigment epithelium was grown to confluence. Organ and cell cultures were treated with latanoprost and/or dexamethasone for 72 h. The activity of MMP-2, -3 and -9 was assessed using zymography. The synthesis pattern of MMPs and TIMP-1 and -2 was identified using immunostaining.

RESULTS

Treatment of explant organ cultures with 10 micrograms/ml of latanoprost induced a mean upregulation of MMP-2 by 36%, MMP-3 by 112% and MMP-9 by 156% as seen by zymography. Dexamethasone 500 nm reduced the amounts of secreted MMP-2 by 13%, MMP-3 by 69%. MMP-9 was not detectable in the media of corticosteroid-treated explant organ cultures. The addition of 10 micrograms/ml of latanoprost to dexamethasone-treated cultures increased MMP-2 by 14%, MMP-3 by 43% and MMP-9 by 49%. Using immunohistochemistry we found staining with antibodies against MMP-2, -3, -9 and TIMP-1 and -2 within the ciliary body, and only to a lesser degree in the trabecular meshwork. Latanoprost treatment caused an increase of 29% in MMP-2 (p < 0.0001), 98% in MMP-3 (p < 0.0001) and 108% in MMP-9 (p < 0.0001). Dexamethasone reduced the staining for MMP-2 by 32% (p < 0.0001), for MMP-3 by 33% (p < 0.0001) and for MMP-9 by 83% (p < 0.0001). Almost no change in staining for MMPs was detectable in the trabecular meshwork. Neither latanoprost treatment nor dexamethasone induced significant changes (p < 0.93) in the secretion of TIMPs. In the media of non-treated retinal pigment epithelium (RPE) cells the only MMP detected was MMP-2. RPE cells in culture did not respond to either treatment with a change in their MMP secretion.

CONCLUSION

We detected a profound upregulation of both MMP-3 and MMP-9 and a mild induction of MMP-2 through latanoprost in the ciliary body, but not the trabecular meshwork or RPE cells. Corticosteroids, on the other hand, downregulated MMP expression in both tissues. This inhibiting effect of corticosteroids on MMP production was reversed by latanoprost.