An immunohistochemical study of abnormal keratinocyte differentiation in molluscum contagiosum.

To investigate abnormalities in the keratinization process in lesional epidermis of molluscum contagiosum, production of filaggrin, loricrin, Ted-H-1 antigen, involucrin, cystatin A and CD95 ligand (CD95L) was investigated using specific antibodies. Anti-filaggrin monoclonal antibody (MoAb) did not react with keratohyalin granules (KHG), but with the substance around virus particles in the stratum corneum. KHG reacted with anti-loricrin polyclonal antibody (PoAb) and anti-Ted-H-1 MoAb. Anti-involucrin PoAb and anti-cystatin A PoAb reacted with materials in the cytoplasm of the middle stratum spinosum to the stratum granulosum. CD95L was expressed in the cell membrane region of the living cell layers in lesional epidermis. These observations suggest that the keratinization process may be altered in molluscum contagiosum.