Lysosomal vesicles, giant granules, and erythrophagocytosis in chédiak-higashi syndrome.

Abstract

Chediak-Higashi syndrome (CHS) is a rare autosomal recessive disorder characterized by partial oculocutaneous albinism, recurrent infections, and mild bleeding tendency [1]. Mutations in the lysosomal trafficking regulator gene (LYST) localized to chromosome 1q42-q44 are responsible for the disease [2]. Lysosomes of hematopoietic cells, particularly granulocytes and monocytes, are enlarged to form vesicles [3]. Giant inclusions in hematopoietic cells are the most reliable diagnostic clinical criterion for CHS. The main differential diagnosis is Griscelli syndrome, a rare autosomal recessive disorder caused by mutations in the MYO5A or RAB27A genes. This syndrome also manifests with partial albinism and immunodeficiency and it progresses towards the accelerated phase as in CHS, but it differs from CHS in view of the absence of giant intracytoplasmic granules in the leukocytes or by genetic analysis [4,5]. Approximately 85% of CHS patients develop a lymphoproliferative infiltration called “accelerated phase” compatible with hemophagocytic lymphohistiocytosis [1].