Expression and localization of HBsAg in corneas from HBsAg-seropositive donors preserved in medium-term preservation solution and glycerol.

Objectives: Due to the severe shortage of donor corneas for transplantation in China, corneal component transplantation may expand the available donor pool. This study aims to evaluate the safety and feasibility of corneal component transplantation by examining the distribution of hepatitis B surface antigen (HBsAg) in corneas from HBsAg-seropositive donors under different storage media.

Methods: Ten corneas (from 6 donors) donated between December 2019 and March 2021 and stored at the Eye Bank of Xiangya Third Hospital, Central South University, were analyzed. Serum HBsAg levels were quantified using enzyme-linked immunosorbent assay (ELISA), while HBV DNA titers in donor blood were measured via polymerase chain reaction (PCR). Immunofluorescence staining was employed to detect HBsAg expression and its localization within corneal layers. Correlations between blood HBV DNA titers and HBsAg fluorescence intensity in corneal tissues were statistically evaluated.

Results: Four corneas from 2 HBsAg-seropositive donors and 1 cornea from 1 HBsAg-seronegative donor were preserved in medium-term preservation solution for <2 weeks. Two corneas from 1 HBsAg-seropositive donor and 2 corneas from another HBsAg-seropositive donor were preserved in glycerol for 1 month and 1 year, respectively. One HBsAg-seronegative donor cornea was stored in glycerol for 1 year. Immunofluorescence staining revealed HBsAg-positive signals in the epithelium of 2 corneas and the endothelium of 1 cornea preserved in medium-term preservation solution (<2 weeks), as well as in the epithelium of 1 cornea stored in glycerol long-term (1 year). Semi-quantitative analysis demonstrated statistically significant differences in HBsAg fluorescence intensity between the corneal epithelium and endothelium (P=0.012), while no significant variations were observed across preservation methods or donors (P>0.05). A positive correlation was identified between blood HBV DNA titers and HBsAg expression in the corneal epithelium (R²=0.707, P=0.036).

Conclusions: HBsAg-positive expression persists in the epithelium or endothelium of donor corneas from HBsAg-seropositive individuals, regardless of preservation in medium-term preservation solution or glycerol. However, no HBsAg expression was detected in the corneal stroma. Higher blood HBV DNA titers correlate with increased likelihood of HBsAg positivity in corneal tissues. This study lays the groundwork for further investigation into the potential use of HBsAg-positive donor corneas in lamellar keratoplasty.