Effects of the alpha 20 mutation on the polymerization of Hb S.

The contribution of the alpha 20 residues in intermolecular contacts present in hemoglobin S fibers was investigated with mixtures of Hb Le Lamentin alpha 2(20)His----Gln beta 2A and of hemoglobin S alpha 2A beta 2(6)Glu----Val and with artificial hybrids alpha 2(20)His----Gln beta 2(6)Glu----Val. This study showed an increased solubility and delay time of polymerization of Hb S in solution only when the mutation at the alpha 20 residue is cis to the beta 6 Val contact. No modification of the polymerization process occurs when the mutation is trans to this beta 6 Val contact. This result is in agreement with the crystal model of Wishner and Love, who showed that one of the two alpha 20 residues of the Hb S tetramer was involved in an axial contact between hemoglobin S molecules in the crystals of Hb S ( Wishner , B.C., Ward, K.B., Lattman , E.E. and Love, W.E. (1975) J. Mol. Biol. 98, 179-194). The present observation is a new illustration of the validity of the crystal model for the structure of the fibers based on pairs of double filaments.

A new silent hemoglobin variant in a black family from French West Indies, hemoglobin Le Lamentin alpha 20 His replaced by Gln.

A new abnormal hemoglobin Hb Le Lamentin alpha 20 (B1) His replaced by Gln was discovered during a survey of cord blood from the French West Indies (Martinique). This variant displays an electrophoretic pattern similar to that of Hb A but can be isolated by isoelectric focusing (IEF) and Biorex 70 chromatography. Family studies showed the presence of this hemoglobin variant in the father and in two of his three children. Hematological data from the carriers were normal.

HTLV-I maternal transmission in Martinique, using serology and polymerase chain reaction.

We have investigated HTLV-I and HTLV-II infection in children born to HTLV-I-seropositive or indeterminate Western blot mothers in Martinique by using the polymerase chain reaction (PCR). Only HTLV-I and no HTLV-II-positive samples were found in this study. All the samples from HTLV-I-seropositive children and adults were PCR positive, whereas the four HIV-I-seropositive and Western blot HTLV-I-negative mothers and their eight children were all PCR negative. Therefore, PCR and serology were in complete agreement in these patients. However, two of the six mothers who were first indeterminate by Western blot, and who later became seronegative, were found positive by PCR. Of the 27 children (ages 2-12 years), born to HTLV-I-seropositive and PCR-positive mothers, 2 were seropositive and PCR positive, 5 were seronegative and PCR positive with 2 primer pairs in gag and pol, and 4 were seronegative and PCR positive with only 1 of the primer pairs. In contrast to an initial rate of transmission of 7% estimated by serology we found a rate of transmission of 28 to 41% (whether or not children who were positive with only one of the primer pairs were included). Thus, our study confirms that PCR is useful in detecting HTLV-I infection in children before seroconversion and underlines the potential lack of sensitivity of serology to detect contaminating HTLV-I blood units in endemic areas.

[Epidemiological characteristics of HIV infection in Martinique]. / Caractéristiques épidémiologiques de l'infection à VIH en Martinique.

The epidemiologic study of HIV infected patients in Martinique from 1985 to 1992 allowed to point out a stability of new cases by year, and confirm the heterosexual transmission in this area. The sexual comportment of Martinicans seems to be different of the continental French people and different between men and women. This constation is important to know for the preventive strategy of the infection.

[Sero-epidemiology of viral hepatitis A, B and delta in Martinique]. / Séro-épidémiologie des hépatites virales A, B et delta en Martinique.

In view of the ethnic and geographical peculiarities of the French department of Martinique and of the endemic character of hepatitis in tropical countries, we studied the prevalence of infections with hepatitis A, B and delta viruses in that region. A group of 10,109 blood donors and a group of about 100 patients were selected on account of their liver symptoms. As regards hepatitis A, the study of the 2 groups was completed by a sero-epidemiological survey of 509 children and teenagers aged from 1 to 18 years. The prevalence of the HB antigen among blood donors was 1.3 per cent, i.e. about 10 times higher than in Europe and 7 times lower than in hyperendemic tropical areas. It was 2.5 times higher in the male than in the female population; 84 per cent of HBs-positive donors had anti-HBe antibodies, 9 per cent had HBe antigen and 7 per cent had neither one nor the other. This distribution is coherent with a population of symptomless carriers. The prevalence of anti-HBs-positive sera was 34 per cent as against 70-95 per cent in highly endemic countries and 4-20 per cent in Europe; 1.9 per cent of the HBs donors studied and 8.8 per cent of the patients had anti-delta antibodies; 11 of the 13 anti-delta-positive subjects had anti-HBe antibodies and 2 had neither HBe nor anti-HBe. Between the ages of 1 and 3 years very few anti-HAV-positive subjects were observed. From 3 to 10 years, the percentage of seroconversions increased moderately. Between 10 and 20 years, the number of positive cases increased considerably reaching 67 per cent at 20 years and 100 per cent at and above 45 years. Among the patients, 97 were positive for IgG (96 per cent) and only 5 for IgM (4 per cent).

[Acute rheumatic fever in Martinique. Epidemiological, clinical and biological study]. / Le rhumatisme articulaire aigu en Martinique. Etude épidémiologique, clinique et biologique.

An epidemiological and clinical survey of rheumatic fever was carried out in Martinique. The clinical manifestations, portal of entry and socio-economic facilitating factors appeared to be the same as those observed in metropolitan France when the disease occurred with a similar frequency. The prevalence and severity of rheumatic fever in Martinique are still high (in 1982, 49 new cases in a population of 300,000, including 12 with severe carditis), but they tend to diminish as the eradication campaign goes on. The reasons for the persistence of the disease and the problems encountered in the eradication campaign are discussed in the light of epidemiological data collected during the last 3 years.

[Epidemiology of HTLV-I infection in its hyperendemic foci (Japan, tropical Africa, Caribbean)]. / Epidémiologie de l'infection par HTLV-I dans ses foyers d'hyperendémie (Japon, Afrique intertropicale, Caraïbes).

HTLV-1 infection is endemic in Japan, black Africa, the Caribbean and several regions of South America. In these foci, the infections is very heterogeneously distributed (variations from village to village, intrafamilial clustering). The virus is transmitted from mother to child, and breast feedings seems to play a major role. Sexual transmission is usually from man to woman. The frequency of transmission by blood transfusion must not be underestimated. It justifies the systematic detection of HTLV-1 infection in areas where it is economically feasible.

HLA antigens in 88 cases of rheumatic fever observed in Martinique.

HLA-A, B, C and DR antigens were studied in 88 patients from Martinique. A modest but significant reduction of B14 and Bw42 antigens was noted as well as an increase in B35 (p less than 0.05) and DR1 antigens (corrected p less than 0.05), two antigens known to be in linkage disequilibrium. These data, which corroborate a previous study for B35, suggest that the unusual antistreptococcal response mounted by rheumatic fever patients is under HLA control.

HIV/HTLV-I coinfection and clinical grade at diagnosis.

A total of 963 HIV-infected patients have been identified or followed up in Martinique since 1985. Medical files were used to retrieve information about age, sex, circumstances of diagnosis, HTLV-I status, and HIV clinical grade at first examination according to CDC criteria from 1987. Complete information was available for 774 patients. At the first clinical examination, the clinical grade of 65 coinfected patients was more severe than that of the monoinfected patients (GIV versus GII, OR = 2.60, p < 0.01), but after adjustment for age and sex, this odds ratio was reduced 1.57. Although this study cannot invalidate the hypothesis of a faster progression toward AIDS of coinfected than of monoinfected patients, it shows that one or several other mechanisms contribute to the different grades of severity at the first clinical examination observed between these two categories of patients. We believe that HTLV-I infection acquired during adulthood is a marker of high-risk behavior and that it might be associated with early or multiple HIV infections.

HLA A,B,C and DR association with insulin-dependent diabetes in Martinique.

HLA-A,B,C, and DR frequencies have been determined in 34 Coloured Martinican IDDM patients to establish the HLA and IDDM associations. HLA A3, B15, B18, Cw3 and DR4 antigens associations with IDDM are confirmed by this study. We found an increase of B21 similar to that found in Asiatic Indians. As in some African Black populations and in Cape coloured people, A1, B8, and DR3 are not increased in our population. We should point out that our patients' ages of onset were low, and that some studies have found DR4 association in young patients and DR3 in older ones. The protective role of DR2 is confirmed here. B35 and Cw4 negative associations have been found. We have observed that the antigens associated with IDDM are decreased in our control population, except DR4, and that the negative associated DR/ and Cw4 antigens are increased compared to the Continental French population. This corresponds with the low IDDM incidence in Blacks and Coloured people.

Anti HTLV-I antibodies and HLA phenotypes in the West Indies.

Sera of supposedly healthy blood donors were screened for the presence of anti HTLV-I p24 antibodies, and HLA typing for A, B, C and DR antigens was performed for 68 seropositive subjects and 92 seronegative controls. HLA phenotypes of the two groups were not significantly different but the level of the antibody response was related to the antigens of the HLA-B (P = 0.02) and -C loci (P = 0.003). Subjects with HLA-B12 or -B21 antigens had lower titres than the others. Subjects with HLA-Cw2 or -Cw7 antigens had higher titres than the others, but only the difference between HLA-B12 positive and negative subjects (P = 0.002) remained significant at the alpha = 0.10 level if the classical, although conservative, Bonferroni procedure was used to correct for the number of comparisons performed.

Locus assignment of two alpha-globin structural mutants from the Caribbean basin: alpha Fort de France (alpha 45 Arg) and alpha Spanish Town (alpha 27 Val).

Two alpha-globin structural mutants were mapped to their encoding loci by in vitro translation of hybrid-selected alpha 1- and alpha 2-globin mRNA. The more highly expressed mutant, alpha Spanish Town (alpha 27Val), is encoded at the alpha 2 locus and the less expressed mutant, alpha Fort de France (alpha 45Arg), is encoded at the alpha 1 locus. These results further define the distribution of alpha-globin structural mutations within the alpha-globin gene cluster and substantiate the dominant role of the alpha 2-globin locus in alpha-globin expression.

[Detection of specific antibodies for HTLV in French blood donors]. / Détection d'anticorps spécifiques du HTLV chez les donneurs de sang français.

HTLV infection was detected in normal French blood donors and haemophiliac patients using HTLV p24 radio-immunoassay. No positive was found in 772 sera from continental blood donors born in continental France or in foreign countries. Among 131 donors living in continental France and born in overseas territories, 2 (1.5%) were found to possess anti-HTLV p24 antibodies. Similarly in a sample of 1 239 donors collected in Martinique, 1.5% were positive. No positive had been found in a sample of 142 continental haemophiliacs.

[Presence of anti-HTLV (human T-cell leukemia virus) antibodies in blood donors from Martinique]. / Présence d'anticorps anti-HTLV (human T-cell leukemia virus) chez les donneurs de sang de la Martinique.

Using indirect membrane immunofluorescence on unfixed HUT 102 cells, 24 out of 184 sera (13%) collected from regular blood donors in Martinique were found positive for HTLV-MA antibodies, 10 being strongly positive (5.4%). Six of these sera were further tested by radio-immunoprecipitation in gel electrophoresis. Antibodies to both viral main core protein (p24) and to virus specific membrane associated glycoprotein (gp 61) were detected in five of those. These findings raise the question of the existence of HTLV related conditions (leukemias or AIDS) in Martinique.

Prenatal diagnosis of hemoglobinopathies: comparison of the results obtained by isoelectric focusing of hemoglobins and by chromatography of radioactive globin chains.

Isoelectric focusing (IEF) of hemoglobin was compared to the classical chromatography of labeled globin chains for 22 antenatal diagnoses of hemoglobinopathies: 11 for beta thalassemia, and 11 for sickle cell disease. In all cases, the two methods gave identical results. The diagnosis was confirmed after birth or abortion. Three fetuses homozygous for beta thalassemia and one homozygous for sickle cell disease exhibited no Hb A by IEF, in contrast to normal fetuses or those heterozygous for one of the two hemoglobinopathies. In addition, blood samples obtained in other centers after abortion of 22 fetuses homozygous for beta + or beta 0 thalassemia exhibited no Hb A when analyzed by IEF. When Hb A was present, the respective proportions of Hb A and acetylated Hb F were determined by densitometry of the IEF gel. The Hb A/acetylated Hb F ratio obtained by IEF correlated well with the beta A/gamma ratio of globin chain synthesis, IEF requires 0.1 mg of unlabeled hemoglobin. It is performed in 90 min and several samples can be analyzed simultaneously. If present, maternal contamination of fetal blood must be eliminated by selective lysis of maternal (RBC) using the Orskov reaction. Improvements in this method to obtain suitable samples for IEF analysis are described.

Sex ratio of human T-lymphotropic virus type I infection and blood transfusion.

The prevalence of human T-lymphotropic virus type I (HTLV-I) infection is higher for females than for males. Blood transfusion is a potential confounding factor which might contribute to this high female:male ratio. Two studies were performed in Martinique (French West Indies) to clarify this issue: a case-control survey comparing the experience of previous blood transfusion among 62 HTLV-I-seropositive and 88 HTLV-I-seronegative blood donors, and a retrospective study of the sex of recipients of blood. Blood transfusion was strongly associated with HTLV-I infection (odds ratio = 6.4, p less than 0.001). Females were more often given blood transfusions (57.9 percent, p less than 0.001) and received a higher percentage of blood units (53.5 percent, p less than 0.05) than could be expected from their proportion in the general population (51.6 percent). Thus, the high female:male sex ratio of HTLV-I-infected subjects might be due partially to a sex difference for blood transfusion.

Study of HLA antigens of the Martinican population.

This is the first time a study has been undertaken on the HLA profile of the Martinican population, a population which is essentially the product of intermixture between African-Negroes and French Caucasians. Two hundred and thirty-eight nonrelated subjects were typed for the A and B loci, 158 subjects for C locus and 128 for DR locus. After analysis of our parameters (antigen and gene frequencies, linkage disequilibria, etc.) and their comparison to those found in the Black and Caucasian control populations, we came to the conclusion that our racially-mixed population is closer to the African-Negro population than to the French Caucasian. A study of the average gene flow enabled us to evaluate the Caucasian contribution as being about 30%. This figure is subject to change inasmuch as racial intermixture continues. Socio-cultural variables are assumed to play a minimal role, given the high rate of illegitimacy.

HTLV-I infection in French West Indies: a case-control study.

A case-control study was performed in Martinique, French West Indies, comparing 66 anti-p24 antibody carriers to 91 seronegative subjects for HTLV-I, matched for age and place of residence. The aim of our study was to identify factors associated with HTLV-I infection and to observe whether clinical examination and biological measurements would reveal any abnormalities among the seropositive subjects. We observed a predominance of females among seropositive subjects (74% compared to 59%, p less than 0.05), and a greater risk due to earlier blood transfusions (p less than 0.001). This survey revealed important differences between cases and controls regarding socioeconomic factors: cases had fewer luxuries or advantages (i.e. bathroom, toilets, refrigerator, telephone, p less than 0.01), were more corpulent (p less than 0.05), and more often widowed, divorced or separated (p less than 0.01) than the controls. Although the differences were not significant, the seropositive donors seemed to be less educated, and were from a lower socioprofessional class than the seronegative donors. With regard to clinical symptoms (infections, adenopathies, splenomegaly, hepatomegaly) and biological parameters (blood count; T-cell subsets, electrophoresis of protids, immunoglobulins, calcemia, antischistosomal antibody), seropositive subjects appeared to be healthy; no parameters, except for alpha 1 globulin (p less than 0.05) and monocytes (p less than 0.05), were found to be correlated with seropositivity; but these two parameters remained within their normal ranges. This study confirms blood transfusion as a risk factor. It underscored the importance of socioeconomic factors for seropositivity.

HLA Gm systems and susceptibility to alcoholic cirrhosis: a study of mixed-race subjects.

The fact that only a small percentage of excessive drinkers develop cirrhosis may be due to a genetic susceptibility to the disease. In order to identify possible genetic risk factors for cirrhosis, we studied mixed-race (Negroid-Caucasian) inhabitants of the French West Indies and compared: (1) the frequency of 51 HLA-A, -B, -C and -DR antigens in 41 subjects with alcoholic cirrhosis and in two control groups consisting of 41 excessive drinkers free of liver disease and 51 healthy non-drinkers; and (2) the frequency of Gm and Km haplotypes in the same groups. Analysis of the Gm system also determined the patients' ethnic origins. The frequency of the HLA-A2 antigen was significantly higher in the cirrhotic patients than in the control group of excessive drinkers (chi 2 = 4.47; P less than 0.05), while that of the HLA-B15 antigen was significantly lower (chi 2 = 5.14; P less than 0.05). The frequency of the Cw4 antigen was significantly higher in the cirrhotics than in the non-drinkers (chi 2 = 5.59; P less than 0.05). However, these differences did not persist when the number of comparisons was taken into account. The frequency of Gm and Km haplotypes was not significantly different in the three groups. In conclusion, complementary studies are required to determine the value of the Gm-Km system as a marker of susceptibility to alcoholic cirrhosis. Our results do not identify an association between HLA antigens and cirrhosis specific to a negroid ethnic group and support the notion that such an association is weak.

Fetal to adult hemoglobin switch in cultures of early erythroid precursors from human fetuses and neonates.

Erythroid burst colonies derived from the cord blood of nine neonates and from the blood and liver of three fetuses aborted after 20 weeks of gestation were grown in plasma clot culture. Their quantitative study revealed a higher proportion of burst-forming units (BFU-Es) in cord blood than in cord blood of normal adults. In addition, colony-forming units (CFU-Es) were present in cord blood but absent from adult blood. Study of haemoglobin synthesis in 14-day cultures of cord blood BFU-Es showed a significantly higher degree of Hb A synthesis than was found in reticulocytes from fresh cord blood; this proportion was, however, similar to that expected in vivo about three weeks after birth. These data suggest that the hemoglobin switch is already programmed in most of the early erythroid precursors present in cord blood or full-term neonates and indicate that the differentiation time is probably of the same order of magnitude in vivo and in vitro. The proportion of Hb A and F synthesis in erythroid bursts was not influenced by the concentration of erythropoietin in the range studied--ie, from 0.5 to 12 international units. Low but identical proportions of Hb A synthesis were found both in erythroid cells from liver after two hours of incubation with [3H]-leucine, and in 14-day liver bursts from fetuses aborted at 20 weeks of gestation.