[Anti-HBc in blood donors. Distribution by sex and age classes].

Among the 21,341 blood donors who gave their blood in 1990, 638 were anti-HBc positive. There is a significant difference between men and women who are 18 to 22 years old and those who are more than 50 years old. In the first case, this difference can be referred to the heterogeneity of the male population and in the second case, to the aftermath of military campaigns.

[Gene mutations of cystic fibrosis in Brittany population].

Eighty percent of chromosomes from cystic fibrosis children in Brittany exhibit the major gene mutation (delta F 508) consisting in deletion of three nucleotide pairs. Eighty-seven chromosomes without the delta F 508 mutation were studied for as yet undescribed gene mutations. A large number of mutations were located in exons 10 and 11.

[Post-transfusion purpura. An unknown cause of acute immune thrombocytopenia. 4 new cases].

Post-transfusion purpura is characterized by the occurrence of acute immune thrombocytopenia 5 to 10 days after transfusion of platelet-containing blood products in subjects who had been alloimmunized to specific platelet antigens. Four cases are reported here. Three of these 4 patients, who had a rare PLA1 platelet phenotype, had developed, during a previous sensitization (pregnancy n = 2, transfusion n = 1), an allo antibody directed against PLA1 antigen.

[Direct diagnosis of predominant mutation delta F508 associated with the mucoviscidosis gene].

The cystic fibrosis locus was mapped on the long arm of the chromosome 7 in 1985. It has recently been cloned and a three base pair deletion has been recognized as the mutation associated with the majority of CF chromosomes (delta F508). CF haplotypes previously defined with tightly associated DNA markers were analysed using PCR (Polymerase Chain Reaction) and allele specific oligonucleotides to determine the presence or absence of this mutation.

[Original technic for preoperative hemodilution permitting deferred autologous transfusion (apropos of 106 cases)].

To carry out normovolemic haemodilution in the best security conditions we elaborate a new method of preoperative haemodilution. Collection of red cell concentrates and adequate compensation are made either in the blood bank or at the patient's bed side. There are two ways of proceeding: *manual plasmapheresis technic is used for the collection of less than 450 ml packed red cells; *collection of more than 450 ml packed red cells is carried out on a PCS Haemonetics cell separator.

[Autosomal dominant polycystic kidney and genetic markers of chromosome 16].

The mutation for autosomal dominant polycystic kidney disease (APKD) has been mapped by linkage analysis on the distal part of the short arm of chromosome 16. We present in this study the results of linkage analysis using the two most tightly linked DNA markers (3'HVR and 24-1) in 183 members of 14 families of a same ethnic origin. We have constructed haplotypes using these two polymorphic probes, and compared the frequency of these on the normal and the affected chromosome.

Immunochemical analysis of platelet autoantibodies in HIV-related thrombocytopenic purpura: a study of 68 patients.

Serum antiplatelet IgG and platelet-associated IgG (PAIgG) were studied in 68 AIDS-free human immunodeficiency virus (HIV)-infected patients with severe immunologic thrombocytopenic purpura (ITP), for the presence of platelet autoantibodies. Serum IgG with antiplatelet activity was found in 72% of the sera. However, the presence of autoantibodies against platelet surface glycoproteins was not found in these sera by means of Western blot and immunoprecipitation procedures.

[Haplotypes associated with the cystic fibrosis gene (CF)].

The linkage relationships between the cystic fibrosis locus and six marker loci allowed us to build 122 haplotypes bearing the CF gene and to compare them to the 122 normal haplotypes. We obtained 13 different marker haplotypes associated with the CF chromosomes and 22 with the normals in our population. To examine the possibility of a correlation between the clinical and the genetical polymorphism of the disease haplotype analysis was carried out taking in account age at diagnosis, severity of the disease and a particular clinical subgroup such as meconium ileus or pancreatic sufficiency.

Study of HLA antigens in systemic lupus erythematosus in the French West Indies.

As incidence of SLE is high in Blacks, we studied HLA and SLE associations in the French West Indies, whose population is racially mixed. Forty-seven coloured SLE patients have been typed in HLA A,B,C and DR. We observed B8 association in nearly all of the studies.

[Prenatal diagnosis of mucoviscidosis. Contribution of DNA analysis of trophoblast biopsies].

The gene for cystic fibrosis has been localised on the long arm of chromosome 7. Genetic engineering techniques now make it possible to inform educated families that it is possible to make an early antenatal diagnosis on chorionic villus sampling at the tenth week of pregnancy. We report our experience on ten antenatal diagnosis that were made.