02095nas a2200445   4500000000100000008004100001260001600042653001200058653002400070653001300094653002800107653002700135653002400162653003800186653002000224653002000244653003100264653001100295653002500306653003000331653002200361653002800383653003000411653002500441653002100466653001700487100001200504700001300516700001400529700001600543700001300559700001800572700001300590700001400603245012800617300001100745490000800756520087100764022001401635       1996                            d  c1996 Mar 0110aAlleles10aAmino Acid Sequence10aArginine10aChi-Square Distribution10aCrystallography, X-Ray10aGenes, MHC Class II10aGenetic Predisposition to Disease10aHLA-DR Antigens10aHLA-DRB1 Chains10aHistocompatibility Testing10aHumans10aLeprosy, Tuberculoid10aMacromolecular Substances10aModels, Molecular10aMolecular Sequence Data10apolymerase chain reaction10aProtein Conformation10aReference Values10aRisk Factors1 aZerva L1 aCizman B1 aMehra N K1 aAlahari S K1 aMurali R1 aZmijewski C M1 aKamoun M1 aMonos D S00aArginine at positions 13 or 70-71 in pocket 4 of HLA-DRB1 alleles is associated with susceptibility to tuberculoid leprosy.  a829-360 v1833 a<p>Evaluation of human histocompatibility leukocyte antigen (HLA) class II genes in 54 cases of tuberculoid leprosy (TL) and 44 controls has shown a positive association with HLA-DRB1 alleles that contain Arg13 or Arg70-Arg71. Among TL patients, 87% carry specific alleles of DRB1 Arg13 or Arg70-Arg71 as compared to 43% among controls (p = 5 x 10(-6)) conferring a relative risk of 8.8. Thus, susceptibility to TL involves three critical amino acid positions of the beta chain, the side chains of which, when modeled on the DR1 crystal structure, line a pocket (pocket 4) accommodating the side chain of a bound peptide. This study suggests that disease susceptibility may be determined by the independent contribution of polymorphic residues participating in the formation of a functional arrangement (i.e., pocket) within the binding cleft of an HLA molecule.</p>  a0022-1007