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The distribution of the G1m (1,2,3,17), G2m(23), G3m(5,10,11,13,14,15,21,28) and Km (1,2) allotypic markers has been examined in 122 unrelated Vietnamese subjects originating from all regions of Vietnam. The 13 observed phenotypes have been explained by means of 8 haplotypes: 5 'major' ones (which are also known to be usual in all other reported Mongoloid populations) and 3 'minor' ones. Consideration of gene frequencies allows easy integration of Vietnamese within the south-north cline of Gm haplotype distribution in East Asia, where they insert between Southern Chinese, on one hand, and Singapore as well as South Central Chinese on the other hand. The observed Km10.290 frequency value revealed to be of the same order of magnitude as the values reported for most other non-Thai Mongoloids.

Allotypes of IgG1, IgG2, IgG3, and IgA2 subclasses were investigated in seven Lebanese communities (three Moslem and four Christian). The Gm-Am haplotypes found were mainly those prevalent in Caucasians with a low frequency of haplotypes usually observed in Africans and Orientals. The difference between highlanders and lowlanders as expressed by G2m(23) was highly significant and suggested a possible adaptation to selective pressure related to the gamma2 genes, possibly due to endemic malaria in the past. Exceptional Gm-Am haplotypes were unambiguously determined by family studies. Some were characterized either by a deletion or a repression or, in contrast, by a partial or total duplication of gamma genes. Two others had uncommon combinations of allotypes: Gm17;23;5,10,11,13,14 A2m1, where G1m (17) was present without G1m (1); and Gm3;23;5,14 A2m1, where the CH3 allotypes G3m (10,11,13) were lacking.

This study presents the pre- and post-treatment levels of specific IgE and IgG and of total IgE in the sera of two groups of grass pollen-sensitive patients, one receiving placebo injection (16 patients), the other being treated by repeated doses of a four-grass pollen extract (17 patients). Total and specific IgE were evaluated by the radioimmunological methods based on the IgE-anti-IgE interaction. IgG specific to the pollen extract was determined by a radioimmunoassay measuring protein-A bound pollen-specific antibodies (IgG). The whole immunoglobulin content specific to the allergen was quantified by a haemagglutination technique. During the treatment period, the relative variations of total IgE, and specific IgE and IgG; levels are significantly different in placebo- and pollen-treated groups: 1) for total and specific IgE, were observed a relative decrease in the placebo group, and stable levels in the treated group; 2) for IgG, the level was stable in the placebo group and a relative increase was seen in the treated group. For most of the patients the specific serum IgE and IgG levels were determined also after the pollen season consecutive to the treatment. During the pollen season, the placebo group is characterized by an increase in specific IgE concentrations and stable IgG levels. The hyposensitized patients showed stable levels of specific IgE and a decrease in specific IgG during the same period. There is a significant correlation between the levels of specific haemagglufination titres and the IgG levels. After the treatment period the haemagglutination titre is significantly lower in the placebo-treated patients than in the pollen-treated ones. A significant positive correlation exists between the levels of specific IgE and IgG before and after treatment, for the 35 patients. Moreover, during hyposensitization, the relative variations of specific IgE and IgG are highly correlated in the treated group only. No significant correlation at the P ≤ 0.05 level is observed between the clinical scores and the levels of the different biological parameters. [ABSTRACT FROM AUTHOR]