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Class I and II HLA typing was investigated before and at various intervals after a 10 Gy total body irradiation delivered over 4 h, prior to allogeneic bone marrow graft for various hematological malignancies, in 14 patients. A reliable class I HLA typing appeared to be possible in almost all cases 6-8 hours after the start of irradiation but was only possible in 5 patients after 24 h. Preliminary results with class II antigens might suggest a more marked "fragility" of this antigen class after irradiation. These results encourage the drawing of blood samples for HLA grouping as soon as possible after accidental whole-body irradiation.

To study the HLA-B7 and HLA-B27 antigenic determinants, hybrid genes between these two alleles were constructed by in vivo recombination in Escherichia coli. After transfection of these genes into P815 (high transfection efficiency recipient) murine cells, the bindings of Bw6, HLA-B7, and HLA-B27 allele-specific mAb were studied, as well as that of human anti-HLA-B7 and anti-HLA-B27 monospecific alloantisera. Most of the HLA-B7 antigenic determinants were assigned to the first external domain of the molecule. Four different epitopic areas could be defined: the Bw6 epitope was associated with residues 82 and 83; the BB7.1 epitope to amino acids 63, 67, and 70; the MB40.2 and MB40.3 epitope to amino acid sequence 177-180, and human alloantisera identified as an epitope associated with residue 9. HLA-B27 antigenicity studied by TM-1 mAb was found to involve residues 77 and 80 in the alpha-1 domain. Results obtained with human monospecific alloantisera allowed the definition of an additional allospecific site associated with the NH2 terminal part on the alpha-1 domain of HLA-B27. Epitope mapping fits with data obtained by sequence comparisons and is discussed with reference to the crystallographic three-dimensional structure of the HLA-A2 molecule.

Resume Les greffes de moelle osseuse de donneur non apparente ont ete realisees avec succes dans certaines indications. Elles sont pratiquees en situation HLA-A, B, DR identique. Cela necessite pour chaque receveur en attente de greffe la recherche permanente de tels donneurs dans une longue liste constituee a partir des panels des differents laboratoires de typage HLA. Cette procedure a ete realisee par la mise en place d'un systeme informatique base sur la constitution et l'interrogation d'un fichier national, implante sur un ordinateur VAX 8250, a partir de fichiers locaux geres sur micro-ordinateurs de type AT 286 sous MS-DOS. L'ordinateur central est en communication reguliere avec chacun des 36 ordinateurs des centres de typage grâce a des modems et au reseau commute pour le transfert de donnees. Apres un an de fonctionnement, le systeme donne satisfaction aux utilisateurs et a permis la localisation reguliere de donneurs identiques a des receveurs en attente.

Our recent segregation analysis, carried out on 27 large pedigrees from a Caribbean island (Desirade), has shown the presence of recessive major gene(s) controlling susceptibility to leprosy per se and nonlepromatous leprosy, respectively. Linkage analysis was performed between each of these two detected genes and each of five markers typed in the Desirade population: HLA, ABO, Rhesus, Gm and Km. No positive significant lod score was observed. However, for leprosy per se close linkage was excluded with Rhesus and Gm (and also with ABO and HLA, considering a lower value for the frequency of the gene controlling susceptibility to leprosy per se). The highest lod score, although not significant, was obtained between the gene for nonlepromatous leprosy and ABO. Our overall results, joined with previous studies and experimental data, suggest that the gene controlling susceptibility to leprosy per se and that controlling susceptibility to nonlepromatous leprosy might be different, acting at successive stages of the immune response to infection with Mycobacterium leprae.