Alelos del sistema principal de histocompatibilidad relacionados con la susceptibilidad al desarrollo de la arteritis de Takayasu / Alleles of the major histocompatibility system associated with susceptibility to the development of Takayasu's arteritis

OBJECTIVE: Since 1972, the relationship between HLA alleles and the susceptibility for Takayasu arteritis (TA) has been studied on different populations. Hence the results up to date are heterogeneous, the objective of the present review is to analyze the relationship between the presence of HLA alleles and the susceptibility for the development of TA considering the ethnic origin of the studied populations. MATERIAL AND METHODS: We carried out a bibliographic review from clinical articles of case and controls studies on different populations on which the relationship between HLA alleles and the susceptibility for TA was studied, published since 1972 until February 2000. RESULTS: We reviewed articles of studies on Asian, Arab, North-American and Mexican Mestizo populations. On Asian populations TA was associated with HLA-A31, -B52, -B39, -B5 and -DR2, on Arabs with HLA-A2, -A9, -B35 and -DR7, on North-Americans with HLA-DR4 and on Mexican Mestizo with HLA-B5, -B52 and -DR6. On the other hand, recent reports establish that several HLA-B alleles (HLA-B52 and HLA-B39) associated with the disease share some residues important on the antigen presentation. CONCLUSIONS: Hence the heterogeneity of the results obtained up to date, it stands out the increase on HLA-B52 and HLA-DR4 reported on ethnically different populations. More recent data point the possible participation of an epitope located on the peptide-binding site of the HLA-B molecule (positions 63 and 67) that seems to be shared by several alleles associated with the disease. These residues might be participating on the presentation of an unknown antigen that would unchain the disease on the genetically susceptible individuals group.

Two novel types of bistratified amacrine cells in the chick retina: a Golgi study

1. The correlation between neurotransmitter substances in specific cell types has renewed interest in the morphology of amacrine cells. In this paper we describe the morphology of two types of amacrine cells in Golgi-stained chick retinas. 2. The first cell type was classified as an asymmetric bistratified amacrine cell suggested to play a role in the formation of complex ganglion cell receptive fields. 3. The second was classified as a bistratified amacrine cell. Their processes were stratified at sublayers 1 and 4 of the inner plexiform layer and their morphological features were similar to those of dopaminergic cells in the chick retina.