Genetic heterogeneity in Sardinia: 15 polymorphisms examined in 11 isolates.

Blood group systems ABO, RH, MNS, KEL, FY, LU and P, red cell enzymes ACP1, PGM1, PGM2, ADA, DIA and PHI, serum markers GC, HP, IGHG1, IGHG3 and IGK were examined in about 900 individuals sampled in 11 Sardinian isolates. The genetic differentiation turned out to be relatively high and the relevance of selected and neutral genes has been evaluated.

Uncommon Gm* haplotypes in the Tunisian population: further contribution to the genetics of the IgG immunoglobulins.

In this work, eight family studies were conducted to establish the suspected unusual Gm* haplotypes in 13 persons (among 418) showing uncommon Gm phenotypes. Usually, the Gm (21 and 28)--or Gm (g1 and g5)--allotypes are both present or absent. Exceptions to this rule were observed: on the one hand, only the Gm (28) allotype was present in 12 persons, and on the other hand, only the Gm (21) allotype was found in 1 person.

Further contribution of common Gm*-Am* haplotypes and Km* alleles in the characterization of the Tunisian population.

The Gm, Am and Km allotypes have been investigated in 405 sera from unrelated students and blood donors coming from the different areas of Tunisia. Thirty Gm and fourty-seven Gm-A2m common phenotypes have been observed. Eleven Gm* and seventeen Gm*-A2m* common haplotypes have been deduced from these phenotypes.

Lymphoid chimerism after allogeneic bone marrow transplantation. Y-chromatin staining of peripheral T and B lymphocytes and allotyping of serum immunoglobulins.

Lymphoid cell engraftment was monitored for several years after bone marrow transplantation by Y-chromatin staining of T and B lymphocytes in the peripheral blood and/or by immunoglobulin allotyping in the serum of 20 of 52 pediatric patients grafted successively between October 1973 and October 1983. Data on 2 patients with severe combined immunodeficiency, grafted earlier in December 1968 and April 1971, are also included. These children received an allogeneic bone marrow graft for leukemia (n = 7), severe aplastic anemia (n = 11), or severe combined immunodeficiency (n = 4) and were informative for this study, because they differed from their donor by sex (n = 16) and/or by immunoglobulin phenotype (n = 13).

Gene conversion in human immunoglobulin gamma locus shown by unusual location of IgG allotypes.

The constant region of the gamma 1, gamma 2 and gamma 3 heavy chains of the human IgG1, IgG2 and IgG3 immunoglobulins carries antigenic determinants or G1m, G2m and G3m allotypes, which are genetic markers of these subclasses. The exceptional presence on gamma 1 and gamma 2 chains of Gm allotypes usually located on the CH3 domain of gamma 3 shows an unexpected clustering of base changes and subsequent identity of short DNA sequences in the CH3 exon of the non-allelic gamma 1, gamma 2 and gamma 3 genes. Such clusters of substitutions are not easily explained on the classical basis of point mutations.