No abstract

Hepatitis B surface antigen (HBsAg) seroprevalence among three major groups of sporadic voluntary blood donors in Greece was studied and compared to the seroprevalence in regular donors. These three groups share many characteristics with the general population. A 6-year retrospective seroepidemiological study was carried out (1991-1996). The study population consisted of donors who were (i) military recruits (n = 80 302), (ii) enlisted military personnel (n = 86 920) and (iii) directed family donors (n = 75403). A specimen was considered as HBsAg positive when found repeatedly reactive by a 3rd-generation immunoassay and confirmed by RIA. The Mantel-Haenszel chi2 procedure was used for stratified analysis of the prevalence rates and Greenland/Robins confidence intervals of the respective weighted relative risk (MHRR) were calculated. The 6-year overall HBsAg seroprevalence among the three sporadic donor groups was 0.84%; this was twice the seroprevalence among a sample of regular donors (n = 45504) in Greece. Seroprevalence was higher among enlisted personnel (1.21 < MHRR = 1.34 < 1.50), during years prior to 1995. Directed family donors had the same overall seropositivity rate as recruits and enlisted personnel. After 1995, all groups had a seroprevalence below 1%, possibly indicating a shift towards lower endemicity in the Greek population.

Frequencies of the thalassaemias in Cyprus were examined by a survey of hospital inpatients and haematological investigations of adult and newborn population samples. The data indicate that 15% of the Greek and Turkish Cypriots are carriers of beta-thalassaemia genes, while 10% of the population carry alpha-thalassaemia genes. These are the highest frequencies of thalassaemia genes found today in any Caucasian population.

Thyroid and pituitary function tests using hypothalamic releasing factors were performed in seven patients with thalassaemia and secondary haemosiderosis and in a control group of seven healthy subjects. The TSH level in the thalassaemic patients (18.07 +/- 1.10 microU/ml) was higher than in the controls (1.01 +/- 0.14 microU/ml, P less than 0.001). After TRH administration the TSH values increased less than in controls. Serum thyroxine and FT41 values were lower in the group of patients with thalassaemia (76.7 +/- 7.8 nmol/l and 19.3 +/- 2.2) compared to the controls (116.1 +/- 6.9 nmol/l, P less than 0.005 and 38.6 +/- 3.6, P less than 0.001). The basal prolactin values did not differ significantly between the two groups, but after TRH administration the increment was significantly lower in thalassaemics than in controls (P less than 0.005). The basal LH values were lower in the thalassaemic patients (1.37 +/- 0.24 ng/ml) than in the controls (3.23 +/- 0.50 ng/ml) and did not increase significantly after LHRH administration. The FSH values were also lower in the thalassaemic group (0.46 +/- 0.15 ng/ml) compared to the controls (2.06 +/- 0.08 ng/ml, P less than 0.001), and increased only slightly after LHRH administration. We conclude that in thalassaemia pituitary deficiency exists, mostly of gonadotrophs, but possibly also for the thyrotrophs and the lactotrophs. Latent primary hypothyroidism has also been found in the thalassaemic group. The functional abnormalities found in both endocrine glands are best explained as a consequence of coexisting haemosiderosis.

Globin chain synthesis was studied in a family with both the Greek (Agamma) type of hereditary persistence of fetal haemoglobin and beta thalassaemia. The ratio of alpha/(gamma+beta+delta) chain synthesis in the hereditary persistence of fetal haemoglobin (HPFH) heterozygotes was 0.97 while in the HPFH/beta-thalassaemia heterozygote it was 2.14. However, calculation of the amounts of haemoglobin synthesized per cell suggests that in the HPFH/beta-thalassaemia heterozygote, the beta- and Agamma-chain genes in cis to the HPFH determinant are unable to compensate for the deficiency of chains imposed by the beta-thalassaemia gene in trans and that the increased synthesis of Hb F is directed by the gamma-chain genes located on the beta-thalassaemia chromosome. The data suggest that synthesis of beta and Agamma chains in the Greek HPFH is fixed at a 'preset' level and indicate that the defect might be due to an abnormality in the rate of transcription of the closely linked beta-, delta- and gamma-chain genes.