Objective: To study the antigen-presenting cells and co-stimulatory factors (HLA class 2 antigen and adhesion molecule) in different grades of vulval intraepithelial neoplasia (VIN).
Material and methods: Forty-five histology specimens were obtained from 21 women who had previously undergone vulval biopsies for VIN and included 12 specimens of VIN I, 5 of VIN II and 28 of VIN III. The CD1a (Langerhans cell/antigen-presenting cell marker) and co-stimulatory factors--HLA Class 2 antigens (LN3) and the adhesion molecule (CD54)--were semi-quantitatively analyzed in all the specimens. Pearson Chi-squared test was used for statistical analysis.
Results: CD1a was increased in 11/12 (91.6%) biopsies with VIN I, in 3/5 (60%) of VIN II and in 4/28(14.3%) of VIN III. There was thus an inverse correlation between CD1a and severity of VIN (Pearson Chi-squared = 26.876, P = 0.001). Qualitatively, there was a basal location of CD1a-positive cells in normal epithelium but had a haphazard distribution in both low grade and high grade VIN. There was no statistical significance in the distribution of LN3 and CD54 in different grades of VIN.
Conclusions: This study shows an alteration in the numbers and spatial arrangement of CD1a-positive Langerhans/antigen-presenting cells in different grades of VIN. There is an increase in the number of cells with CD1a expression in low grade VIN and a decrease in the number of these cells in high grade VIN. Reduction in CD1a expression may reflect the inability of the host to mount an adequate immune response due to reduced antigen presentation in high grade VIN.