Lichen planus in two immunodeficient hosts.

The exact pathogenic mechanism involved in lichen planus (LP) remains obscure. Two patients who have severe immunodeficiency diseases and who developed LP during the course of their illness are reported here. Both patients had hypogammaglobulinemia and disturbed immune function prior to the development of LP. Although such an association could be coincidental, the development of LP may be related to the underlying immune disturbances. Association of LP with several other disorders of the immune system has been previously observed. Other evidence for the possible involvement of an immunopathogenic mechanism in LP includes (1) deposition of immunoglobulin within the colloid bodies and at the dermoepidermal junction, (2) predominantly T cell dermal infiltrate in LP lesions, and (3) existence of clinical and histologic similarities between graft-versus-host disease and LP.