Electron microscopy in Griscelli syndrome

S.F.MuRuoglu*, E.&an*, F.Kaymaz*, B.Kendir*, I.Tezcan**

Hacettepe University Medical Faculty,*Histology &Embryology Department,**Pediatric Immunology Department, Ankara-Turkey

Partial with immundeficiency is a syndrome associating pigmentary dilution and which was first described by Griscelli et al in 1978 [ 11. It is autosomal recessive trait and seems to be extremely rare. Since the original description of two cases in 1978, only 19 patients have been described. But it was tiequently confused with Chediak-Higashi syndrome depending on their similar clinical features and course. However the two syndrome can be differentiated histologically; by lacking of characteristic granulocytic giant and agglomerations of in Griscelli syndrome[2].

The electron microscopic observations revealed numerous melanosomes were in the form of small dense irregularly shaped granules (stage IV-mature type) filled epidermal which arrayed around the nucleus. Mature melanosomes were also seen in dendiritic processes. Adjacent keratinocyte, however contained only sparse melanosomes. No giant melanosomes were detected and no abnormal membrane-bound -like organelles were in cells. These hyperpigmented oval melanocytes contrasting with poorly pigmented adjacent keratinocytes. Though at the beginning of the disease there was any granulocytic giant lysosomes were found in the cells of myeloid series, they were identified in bone marrow biopsies and peripheral blood smears laterly. These giant granules were resembled the those found in Chediak Higashi syndrome as a characteristic feature. These findings appears to be no defect in the synthesis of pigment. But the transfer of pigment granules to keratinocytes is defective. Since the synthesis is continious but the transfer is inefficient, normal cycle of melanogenous is interrupted. Neither giant melanosomes nor membrane-bound lysosomes-like inclusions were detected through the sections during the microscopic examination, those defined (well-known) in Chediak Hiagshi syndrome.

Our findings confirm the previously described features of partial albinism with immunodeficiency, such as melanocytes abnormalities, absent delayed hypersensivity and a severe clinical course characterized by accelerated phases and recurrent infections. In contrast to original description of the disease we consume a transformation to Chediak Higashi syndrome which was not reported before. Further studies concerning Griscelli syndrome with accelerated phase will be necessary to determine the relation with Chediak Higashi syndrome.

References: I. Griscelli C. et al. Am JA4ed 65 /1978) 69I-702. 2. Klein C. et al. J Pediatr 125 (1994) 886-95. Fig 1. Epidermal cell layers composed of keratinocytes and a few mehnocyte

Fig 2. A containing a lot of mature melanosomes