Investigators assessed corneal immunophenotype following simple limbal epithelial transplantation (SLET) or conjunctival-limbal autograft (CLAU) in patients with ocular chemical burns, which represent up to 22% of all ocular injuries and an important cause of limbal stem cell deficiency (LSCD). Impression cytology and immunocytochemistry were used to determine resulting phenotypes following the procedures.
Study design
A total of 20 patients who underwent either SLET or CLAU for more than 270 degrees of LSCD following unilateral chemical burn were prospectively assessed for the presence of cytokeratin 3 (CK3), which indicates normal corneal epithelium, and cytokeratin 19 (CK19), which indicates conjunctival epithelium, to compare the 2 surgical approaches. Impression cytology sampling of the corneal surface followed by immunohistochemistry staining were conducted preoperatively and 6 months postoperatively. Zero percent CK19 was defined as complete reversion to the corneal immunophenotype; <5% was defined as incomplete reversion; and >5% was defined as residual limbal stem cell disease. Results were correlated with clinical findings (symblepharon, corneal vascularization, or corneal clarity).
Outcomes
Mean patient age was 15 years and the interval from injury to surgery ranged from 3 months to 6 years. Sixteen patients returned adequate impression cytology samples for analysis. Six months postoperatively, expression of CK3 and CK19 was not significantly different between patients who underwent SLET and CLAU. On average, patients who received either SLET or CLAU exhibited incomplete reversion to the corneal immunophenotype: SLET CK3 increased from 2% to 70% and CK19 decreased from 85% to 6%; CLAU CK3 increased from 2% to 71% and CK19 decreased from 83% to 6%. Three cases (2 SLET, 1 CLAU) exhibited complete reversion to the normal corneal immunophenotype, which correlated clinically with clear corneas and improved vision. Incomplete reversion to the corneal immunophenotype correlated with hazy corneas, blunted visual recovery, and limited symblepharon recurrence.
Limitations
This study is limited by small sample size, heterogenous severity of limbal stem cell disease, and the limited 6-month follow-up. Longer longitudinal follow-up of the immunohistochemical profile of the corneal epithelium after SLET and CLAU may further elucidate potential differences, if any, in the clinical outcomes of these procedures.
Clinical significance
This study provides immunohistochemical evidence suggesting that SLET, a less invasive procedure that poses fewer risks to the healthy donor eye in patients with unilateral chemical burns and limbal stem cell deficiency, yields comparable benefits to CLAU in the recipient eye.