Autologous serum has been advocated for the treatment of persistent corneal epithelial defects and other ocular surface disorders which may be a local manifestation of a systemic disease. Many of these underlying disorders are cytokine-mediated and require immunosuppressive therapy. The systemic disease and medication could potentially influence the epitheliotrophic capacity of serum eye drops. We compared the effect of serum from healthy and immunosuppressed donors in a human corneal epithelial cell culture model.
Serum was prepared under standardised conditions from full blood samples of 10 healthy donors and 10 patients suffering from rheumatoid arthritis. All patients were treated with prednisolone and methotrexate, one also with azathioprine. In these serum samples EGF, FGF, HGF, PDGF-AB, TGF-beta1, fibronectin, vitamin A and E as well as IL-6 were quantified by means of routine ELISA or HPLC technology. SV-40 immortalised human corneal keratinocytes were cultured in 96-well plates at 37 degrees C, 5 % CO (2) with a fully defined culture medium. At 30 % confluency the culture medium was substituted by one of the test preparations. Proliferation of cell cultures was quantified by means of a luminescence-based ATP assay in dose-response experiments. A colony dispersion assay was used to examine the effect on cell migration and differentiation was assessed by means of scanning electron microscopy.
Serum from healthy donors differed from serum of immunosuppressed individuals suffering from rheumatoid arthritis only in that it contained significantly higher amounts of fibronectin and TGF-beta1. Support of proliferation, migration and differentiation of corneal epithelial cells was dose-dependent, but no significant difference was observed between the serum of the two different groups of donors. At a dilution of 25 % serum of healthy donors showed a significantly higher stimulation of migration than serum of immunosuppressed patients.
The effect of serum on migration but not proliferation is affected by systemic diseases requiring immunosuppression. If an epithelial defect of a patient with rheumatoid arthritis does not respond to treatment with diluted autologous serum, undiluted serum should be tried since the positive effect of serum on cell migration is positively correlated with dose.