We describe the occurrence of a chromosome with a G----A mutation at position +22 relative to the Cap site that was found in five patients with beta-thalassemia. All patients had a common type of beta-thalassemia mutation on the second chromosome, namely the frameshift at codon 8 (-AA), the IVS-I-110 (G----A) and the IVS-II-1 (G----A) mutations. The beta genes of two patients, including the 5' and 3' untranslated regions, were completely sequenced and no other mutations, except a few polymorphic sites, were observed. Dot-blot analyses failed to demonstrate this G----A mutation at +22 in nearly 400 beta-thalassemia chromosomes and 180 normal chromosomes. Heterozygotes have the features of a high Hb A2-beta-thalassemia heterozygosity, although the hematological parameters might be less abnormal than observed in heterozygotes for the more common beta-thalassemia mutations. The possibility has been presented suggesting that this mutation might impair the binding of mRNA to ribosomes. Another mutation in this segment of DNA, i.e. a C----G mutation at position +20, is observed exclusively on a chromosome which also carries the C----G mutation at IVS-II-745. It is postulated that the +20 C----G mutation accentuates the beta-thalassemia condition caused by the IVS-II-745 mutation; the mechanism might be similar to that suggested for the G----A at +22 mutation.

Epidemiological studies demonstrated that the exposure of different air pollutants including particulate matter (PM) has been related to adverse effect on immune system. Current study was designed to investigate cytokines in blood plasma of adolescent persons continuously exposed to different degrees of ambient air pollutions. Tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), IL-12p40, and IL-10 were chosen as cytokines of proinflammatory and anti-inflammatory immune response. The peripheral venous blood was taken from adolescents living in the cities of Stara Zagora region, Southeast Bulgaria, that is, in Stara Zagora, Kazanlak, and Chirpan. The quantity of cytokines in plasma samples was determined by enzyme-linked immunosorbent assay. Results demonstrated that youths living in Stara Zagora showed significantly smaller quantity of TNF-α, compared with adolescents from Kazanlak and Chirpan. Moreover, adolescents living in Stara Zagora showed significantly higher quantity of IL-10 than students from Kazanlak and Chirpan. Analysis of the data of air quality gives reason to assert that PM10 and PM2.5 have been the main atmospheric pollutants around the monitoring points. The complex air quality assessment based on these criteria determined that the highest air pollution was in the city of Stara Zagora, followed by Chirpan and the relatively unpolluted town was Kazanlak. We concluded that air pollutants, mostly PM2.5, can modulate cytokine production and can change the balance between proinflammatory TNF-α and anti-inflammatory IL-10 production. Increased levels of IL-10 combined with decreased level of TNF-α in adolescents living in Stara Zagora can serve as a biomarker for suppression of T helper 1 (Th1) cell-mediated immunity and exacerbation of Th2 humoral immune response and could be a prerequisite for the development of allergic and autoimmune diseases.

The gamma chain compositions of the fetal hemoglobins of 2453 newborn babies from East Asian countries (1350 babies), from Italy, Yugoslavia, Bulgaria, and Georgia (417 Caucasian babies), and 686 black babies from Georgia were determined by high pressure liquid chromatography. Unusual results for a limited number of babies were confirmed by chemical analyses, and were evaluated further by family studies. Statistical analyses indicated high gene frequencies for the A gamma T chain in Italian (f = 0.237), Yugoslavian and Bulgarian (f = 0.238), and white Georgia babies (f = 0.224), a lower frequency in Japan (f = 0.178), and India (f = 0.173), and particularly in mainland China (f = 0.079). The A gamma T gene frequency in normal (AA) Black babies was 0.102. When a beta S or beta C mutation was also present this frequency was greatly decreased, particularly in babies with the AC condition (f = 0.036). These results suggest the near absence of the A gamma T mutation on the chromosome also carrying the beta C determinant. Most babies had the expected G gamma values which vary between 60 and 80%, but several (mainly black) babies had higher values (between 80 and 90%), while one normal black baby had a G gamma value of (nearly) 100%. This condition may be a form of A gamma +1-thalassemia and has been discussed in detail elsewhere (Blood 58:491-500, 1981). Thirty-five clinically normal (mainly Chinese, Indian, and Japanese) babies had G gamma values of about 40%. Twenty-six babies had A gamma I values of about 60%, while the remaining nine babies had A gamma T and A gamma I chains in a ratio of either 1 to 2 or 1 to 1. Two additional newborns did not produce any G gamma chains, but had only A gamma I chains or A gamma T chains. Family studies failed to indicate a specific hematological abnormality. These unusual ratios between the G gamma and A gamma (either A gamma I or A gamma T) chains have led to speculations regarding possible genetic abnormalities present in these infants.

Alu sequences represent a specific human family of interspersed repetitive DNA, with a copy number in excess of 500,000 within the human genome. Alu repeats are rarely present in protein-coding regions of mature RNA, and only a few Alu insert mutations have been described so far. In this paper we present an Alu retroposition event in a family with a severe form of hemophilia A. The inserted Alu element belonging to the youngest Yb8 subfamily disrupts the reading frame at methionine 1224, exon 14 of the factor VIII gene, leading to a stop codon within the inserted sequence. This observation indicates that the retroposition of Alu elements is a continuing process possibly generating various human genetic defects.

In an ongoing effort to identify point mutations causing beta-thalassaemia, we have found two previously unreported mutations which are located in the Poly A site of the beta-globin gene. The screening programme used amplified DNA and dot-blot hybridization with several 32P-labelled oligonucleotide probes. DNA samples which remained unidentified by this methodology were subjected to sequencing with 32P-labelled primers and modified T7 DNA polymerase. The newly discovered mutations were confirmed by the dot-blot hybridization technique. One type concerned an AATAAA----AATGAA mutation in the polyadenylation site and was found in one family from Yugoslavia (including one patient with the C----T mutation at codon 29 in trans), one from Bulgaria (the patient had the G----A mutation at IVS-I-110 in trans), and one from Greece (this patient had the C----G mutation at IVS-II-745 in trans). Haematological data for three simple heterozygotes suggested a rather mild beta(+)-thalassemia. The second type involved an AATAAA----AATAGA mutation and was found in one family from Malaysia. The propositus had the beta E mutation on the other chromosome, was originally diagnosed as mild Hb E-beta(+)-thalassaemia, and had Hb A and Hb E percentages which were nearly the same.