Allogeneic Versus Autologous Serum Eye Drops

Serum eye drops (SEDs) are used to treat patients with dry eyes and other diseases, like corneal defects. SEDs are used in ophthalmic cases where conventional eye drops have insufficient effect. The use of SEDs in dry eye patients usually has a rapid effect. Most patients claim the effect to be instantaneous and all symptoms improve by 48 hours [1].

There is evidence suggesting that serum may enhance corneal epithelial healing [2]. Some biologically active substances are thought to contribute to the positive effects, like epidermal growth factor, fibroblast growth factor, fibronectin, and vitamin A.

Autologous SEDs are used internationally on a regular basis, and allogeneic SEDs are becoming increasingly popular. In the Netherlands, only autologous SEDs are in use.

Obtaining autologous SED is an organizational burden. Patient-related problems are old age, travelling, or travelling with low vision and sometimes immobility due to other diseases. Sometimes venipuncture is impossible due to poor access. Medical conditions such as inability to donate large amounts of whole blood due to previous cerebrovascular accidents or cardiovascular disease, anemia, or use of certain medication may prevent collection of blood for SEDs. Patients affected with hematological diseases, bacterial, viral or fungal infections are also unsuitable for production of autologous SEDs. In 2.3% of donors for preparing autologous SEDs, a systemic infection can be detected [3]. In the UK, use of autologous SED is restricted largely due to cost [4]. Logistically, it is a problem that it takes time as well as joint effort of several departments in the hospital to prepare the SEDs, causing considerable waiting time for the patient. Further, the use of allogeneic drops allows immediate access to SEDs in case time is limited to prevent corneal scars, ulcers, infiltrates or even transplants, epithelial defects or low vision due to epithelial surface disease.

Allogeneic SEDs are derived from healthy donors and are produced by a blood bank facility. Blood banks are experienced and equipped to produce blood products in a good manufacturing practice (GMP) environment. They can perform quality control, and are able to produce larger quantities that are quickly available. For our study, donors with blood group AB will be selected to ensure ABO compatibility. Donors are further selected to be males that never had a blood transfusion to minimize anti-HLA titers.

No prospective double blind randomized cross-over trials are known to exist to detect a difference in result between the effect of allogeneic SED or autologous SED for ocular surface disease. This pilot study is intended to obtain insight in the ability of autologous and allogeneic SEDs to improve patient dry eye sensation. Our hypothesis is that autologous SEDs (in a 1:1 dilution with saline) result in an improvement of the patient dry eye sensation, while allogeneic SEDs (in a 1:1 dilution with saline) do not.