Complete nucleotide sequence of an African human T-lymphotropic virus type II subtype b isolate (HTLV-II-Gab): molecular and phylogenetic analysis

We report the first complete nucleotide sequence of an African human T-cell lymphotropic virus type II. This new strain, called HTLV-II-Gab (Gab), was obtained from the uncultured peripheral blood mononuclear cells of a 44-year-old healthy Gabonese male who lived in a remote rural area, with neither history of blood transfusion nor sexual intercourse with non-Africans. Using nested PCR, 25 overlapping fragments, representing the entire proviral genome, were obtained, cloned and sequenced. The overall nucleotide sequence comparison with the four other available complete HTLV-II genomes indicated that Gab was more closely related to the HTLV-II subtype b prototypes (98.9, 99.3 and 98.2% nucleotide similarity with G12, NRA and GU respectively) than to the subtype a prototype (95.1% nucleotide similarity with Mo). Restriction profiles studies and phylogenetic analyses confirmed that Gab was a subtype b strain. However, this strain represents a newly described restriction fragment length polymorphism subtype, closely related to one of the rare partially sequenced African isolates originating from a pygmy living in Cameroon (PYGCAM). Nevertheless, the very low genetic divergence observed between this new African strain and the American strains raises several questions on the origins and level of genetic variability over time of this human retrovirus.

Fluorometric detection of HIV-1 genome through use of an internal control, inosine-substituted primers, and microtiter plate format

We describe a PCR-based fluorometric assay for the detection of the HIV-1 genome. This technique consists of a reverse hybridization with oligonucleotide probes covalently coated onto a microtiter plate as a solid support. Several improvements to the PCR amplification and detection steps gave greater sensitivity and specificity for HIV-1 screening and resulted in a convenient and rapid technique. False-positive results were avoided by using uracyl DNA glycosylase. False-negative results from the presence of PCR inhibitors were detected by coamplifying an internal control with the viral sequence. False-negative results from viral genome variability were limited by using two pairs of primers and by incorporating inosine at the primer positions corresponding to viral polymorphic nucleotides. Furthermore, the hybridization buffer and enzymatic reaction were optimized to increase the assay's sensitivity. The sensitivity and specificity of the fluorometric detection were similar to those of radioisotopic oligonucleotide solution hybridization; however, hands-on time was reduced, and the use of radioactivity was eliminated. We have used this technique routinely on 115 samples and obtained 100% specificity and high sensitivity (only one false-negative result) according to viral culture and (or) serological status of the patients.

Fluorometric detection of HIV-1 genome through use of an internal control, inosine-substituted primers, and microtiter plate format

We describe a PCR-based fluorometric assay for the detection of the HIV-1 genome. This technique consists of a reverse hybridization with oligonucleotide probes covalently coated onto a microtiter plate as a solid support. Several improvements to the PCR amplification and detection steps gave greater sensitivity and specificity for HIV-1 screening and resulted in a convenient and rapid technique. False-positive results were avoided by using uracyl DNA glycosylase. False-negative results from the presence of PCR inhibitors were detected by coamplifying an internal control with the viral sequence. False-negative results from viral genome variability were limited by using two pairs of primers and by incorporating inosine at the primer positions corresponding to viral polymorphic nucleotides. Furthermore, the hybridization buffer and enzymatic reaction were optimized to increase the assay's sensitivity. The sensitivity and specificity of the fluorometric detection were similar to those of radioisotopic oligonucleotide solution hybridization; however, hands-on time was reduced, and the use of radioactivity was eliminated. We have used this technique routinely on 115 samples and obtained 100% specificity and high sensitivity (only one false-negative result) according to viral culture and (or) serological status of the patients.

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.

Prospective monitoring and quantitation of residual blasts in childhood acute lymphoblastic leukemia by polymerase chain reaction study of delta and gamma T-cell receptor genes

We have developed a strategy based on polymerase chain reaction (PCR) for detecting all possible gamma T-cell receptor (gamma TCR) rearrangements and the most common delta TCR rearrangements found in B-lineage and T-acute lymphoblastic leukemia (T-ALL). The segments amplified from blasts are then directly sequenced to derive clonospecific probes. From a series of 45 patients aged 1 to 15 years (42 B-lineage ALL, 3 T-ALL), 35 (83%) could be followed for minimal residual disease with at least one clonospecific probe. Detection of clonal markers using clonospecific probes routinely allowed the detection of 1 to 10 blasts out of 10(5) cells as determined by serial dilutions of the initial samples. Residual disease was quantitated by a competitive PCR assay based on the coamplification of an internal standard. Twenty children were prospectively followed for periods varying from 7 to 30 months. In most children, a progressive decrease of the tumor load was observed, and blasts became undetectable within 6 months after the initiation of treatment. A slower kinetics of decrease in tumor cells was found in three children. These three patients relapsed with blasts that continued to display the initial clonospecific markers. Three other children had a central nervous system relapse despite the absence of detectable medullary residual disease. The use of both delta and gamma TCR genes as clonal markers, as well as simplification in the methods to detect and quantify residual blasts reported here, will allow the study of the large number of patients required to determine the role of the detection of minimal residual disease by PCR in the follow-up of childhood ALL.

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.

Prevalence of HTLV-I and HTLV-II infection in Gabon, Africa: comparison of the serological and PCR results

A cluster sampling survey was performed in 1989 in Libreville, Gabon, to determine HTLV-I and HTLV-II prevalence and to compare the efficacy of polymerase chain reaction (PCR) and serology in detecting HTLV-I and HTLV-II infections. A total of 322 sera from adults were tested by ELISA and by Western blot (WB). The WB patterns were interpreted according to WHO criteria and those of the manufacturer. PCR analysis using primer pairs in the gag and pol region, with a specific probe for HTLV-I and HTLV-II, was performed on the lymphocytes of the 322 adults. In addition, 134/322 samples were re-tested with tax primers, in a second laboratory. Using WHO criteria, 8/322 (2.5%) samples were positive on WB and 25 were indeterminate; with the criteria of the kit, 26/322 (8.1%) were positive and 7 were indeterminate by WB. By PCR, 13 (4%) samples were positive, including 12 for HTLV-I (3.7%) and one for HTLV-II (0.3%). All 8 seropositive samples (by the WHO criteria) were positive by PCR, as were 4 out of 25 indeterminate samples. Only one out of 289 seronegative samples was positive by PCR. In contrast, only 12/26 positive samples by the kit criteria were confirmed by PCR. These results confirm the relatively high HTLV-I/II seroprevalence observed in Gabon. HTLV-I infection is preponderant, but HTLV-II is also present. The WHO criteria for WB give a better fit with PCR results than the kit criteria for WB. In the absence of a specific confirmatory test and based on the uncommon "seronegative" HTLV-I/II infection, the indication for PCR appears limited to the positive WB samples (to differentiate HTLV-I and II infection) and to the indeterminate WB samples.

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.

[Epidemiology of HTLV-I infection in its hyperendemic foci (Japan, tropical Africa, Caribbean)]

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.

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.

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.

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.

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.

[Sero-epidemiology of viral hepatitis A, B and delta in 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).

Study of HLA antigens in systemic lupus erythematosus in the French West Indies

As incidence of SLE is high in Blacks, we studied HLA and SLE associations in the French West Indies, whose population is racially mixed. Forty-seven coloured SLE patients have been typed in HLA A,B,C and DR. We observed B8 association in nearly all of the studies. B15 association, more frequent in Caucasians, was found, also B53 association, a Black variant of B5 more frequent in Blacks. We did not find any class II association.

HTLV-I-associated tropical spastic paraparesis in Martinique: a reappraisal

Human T-lymphotropic virus type I (HTLV-I)-associated tropical spastic paraparesis in Martinique has been identified in 54 patients, 49 women and 5 men. This myelopathy represents an endemic problem on this island and the earliest documented case dates from 1952. A blood transfusion history was obtained in 7 of the 54 patients (13%). There was a preponderance of cases from the northern Atlantic coast of Martinique, the most humid region on the island. The prevalence in this region reached 49.5 per 100,000, compared with the global prevalence of 11.9 cases per 100,000 for the island. An immune-mediated mechanism may be important in the pathogenesis of HTLV-I-associated tropical spastic paraparesis.

Hemoglobin S Antilles: a variant with lower solubility than hemoglobin S and producing sickle cell disease in heterozygotes

We have found a sickling variant, Hb S Antilles, alpha 2 beta 2(6 Glu----Val, 23 Val----Ile), that has the same electrophoretic mobility as Hb S but a distinct isoelectric focus and produces sickling in the carriers of the Hb A/S Antilles trait. The carriers' erythrocytes tend to sickle at O2 partial pressures similar to those that induce sickling in Hb S/C disease. Pure deoxy-Hb S Antilles is 50% as soluble as deoxy-Hb S (saturating concentration = 11 g X dl-1 compared to 18.4 for Hb S). Dilute solutions of pure Hb S Antilles have a lower oxygen affinity than those of Hb A or Hb S (partial pressure for 50% binding is 9 mm Hg compared to 5.5 mm Hg for Hb A or S at pH 7.00). A/S Antilles erythrocytes have a much lower oxygen affinity than A/S cells; this is further decreased in dense cells fractionated on a Percoll density gradient. Their oxygen equilibrium curves had anomalous shapes like those of S/S cells. Fiber formation in the erythrocytes of Hb S Antilles carriers is clearly due to its low solubility and oxygen affinity, showing that heterozygosity for this hemoglobin presents another sickle cell syndrome and suggesting that Hb S heterozygotes who exhibit symptoms of sickle cell disease should be carefully screened for double mutations.

[Acute rheumatic fever in Martinique. Epidemiological, clinical and biological study]

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.

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.

Interaction of hemoglobin Siriraj with hemoglobin S: a mild sickle cell syndrome

Hb Siriraj is a beta chain variant in which beta 7 (A4) Glu is replaced by a lysine. It has been encountered in association with Hb S in a black man from Martinique. Some properties of Hb Siriraj are compared, particularly, with Hb C [alpha 2 beta 26(A3)Glu----Lys], and a study of its in vitro interaction with Hb S is discussed.

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.

Antibodies to HTLV-I p24 in sera of blood donors, elderly people and patients with hemopoietic diseases in France and in French West Indies

Human T-cell lymphoma/leukemia virus type I (HTLV-I) is a type-C retrovirus originally isolated from patients with leukemia or lymphoma involving mature T lymphocytes. Epidemiological studies have shown that HTLV-I infection occurs not only in leukemic but also in normal people in at least two areas of the world: the Caribbean basin and the South-West of Japan. We report here the results of a large seroepidemiological study of HTLV-I infection in normal French blood donors, elderly subjects living in institutions and patients with various malignant hemopathies, obtained by the classical HTLV-I p24 radioimmunoassay. We were unable to demonstrate antibodies to HTLV-I in 510 sera from French volunteer blood donors born and living in continental France or in sera from 262 blood donors born in other countries (mainly in Europe and North Africa) and living in continental France at the time of collection. In contrast, among 131 sera from blood donors born in French overseas territories (French Guiana, French West Indies, and Reunion) but living at the time of collection in continental France, 2 (1.5%) were found to possess anti-HTLV-I antibodies. In a sample of 2,597 blood donors from Martinique, 39 (1.5%) were positive. A positive correlation with age was observed whereas no statistical relationship was found between HTLV-I antibodies and sex, red cell blood groups or the place of residence in Martinique. On the other hand, a very high level of positive values was observed in Martinique among old people living in institutions, 14% of those aged over 60 years being positive. HTLV-I-associated hematological malignancies have not been observed in patients born and living in continental France whereas a large number exist in the French West Indies. In the same area, the presence of anti-HTLV-I antibodies in 12% of patients with myeloma, a typical B-cell disease, merits attention.

[Detection of specific antibodies for HTLV in French blood donors]

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.

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.

Two new cases of heterozygosity for hemoglobin Knossos alpha 2 beta 2 27 Ala----Ser detected in the French West Indies and Algeria

Hb Knossos alpha 2 beta 2 27 Ala----Ser was first described in a Greek family as a silent beta(+) thalassemia variant. Reexamination of 5,000 isoelectric focusing patterns of patients with microcytosis allowed the presumptive identification of two additional propositi. The first originated in the French West Indies (Martinique) and the second in Algeria. A branch of the family of the second propositus was also investigated. Identification of Hb Knossos was made easily in the first family since one member was a double heterozygote for Hb S and Hb Knossos. In the second family HPLC elution of the peptide fragments obtained by tryptic digestion of the aminoethylated beta chain allowed the isolation and characterization of an abnormal beta T3 peak with expected beta 27 Ala----Ser substitution. The Hb Knossos heterozygote from Martinique, besides an elevated alpha/beta globin chain ratio, had an elevated Hb A2 concentration in contrast to the Greek and Algerian families in which it was normal. This difference in phenotypes may be explained by the occurrence in the Mediterranean cases of a delta gene abnormality, presumably delta(0) thalassemia, in position cis to the abnormal beta-globin gene.

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.

[Detection of haemoglobinopathies at birth, using isoelectric focalization (author's transl)]

The incidence and nature of haemoglobinopathies were investigated at birth in Martinique, where 4635 samples of umbilical cord blood were examined. Conventional blood values were determined, and a new, extremely simple and highly selective test was performed: isoelectric focalization. Abnormalities were found in 14.3% of blood samples, viz: A/S 7.25%, A/C 3.17%, S/S 0.17%, S/C 0.24%, C/C 0.04%, other mutations 0.63% alpha-thalassaemia minor (alpha 1-thal) 1.72% and isolated microcytosis 1.01%. Unusual abnormalities included 7 different mutations of the 4a-chain, 3 of the beta-chain and 3 of the gamma-chain. The clinical and epidemiological importance of such investigations is emphasized.

[Antenatal diagnosis of sickle-cell anaemia by DNA analysis of amniotic fluid cells. A preliminary study in the French West-Indies (author's transl)]

The genetic polymorphism previously reported to be associated with the sickle-cell (beta S) gene in black U.S.A. citizens was studied in the population of two French West-Indies islands in order to evaluate its potential application to the antenatal diagnosis of sickle-cell anaemia. The polymorphism consists of a change in the DNA sequences located near the 3' end of the beta globin gene. The change can be detected by means of the restriction endonuclease Hpa I. When cellular DNA is digested with this enzyme, the beta globin gene is contained in a DNA fragment measuring either 7.6 or 13.0 kilobases (kb). In 70% of SS homozygous subjects in Martinique and 57% in Guadeloupe the beta S gene was carried by a 13.0 kb DNA fragment, whereas the normal beta A gene was carried by a 7.6 kb DNA fragment. This polymorphism would make it possible to detect the foetal beta S gene in the DNA of amniotic fluid cells by linkage analysis.

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.

Fetal hemoglobin synthesis in culture of early erythroid precursors (BFU-E) from the blood of normal adults

BFU-E from the blood of 14 normal adults have been grown by the plasma clot technique. The hemoglobins synthesized in burst colonies were purified from other proteins by affinity chromatography on Sepharose-haptoglobin. The radioactivity incorporated in the globin chains was estimated by CM-cellulose chromatography in urea. The number of bursts scored at the 14th day of culture fluctuated between 50-130 (average 86, s: 29) for 10(6) mononuclear plated cells. A constant reactivation of fetal hemoglobin was found (from 1.4% to 11%, mean value 5.8%, s:3.07), but was lower than previously described, mainly because of the highly selective purification of Hb. This reactivation of fetal hemoglobin was not dependent upon the concentration of erythropoietin (from 1 U/ml to 6 U/ml) nor on the purity of the erythropoietin preparations (from 6 U/mg of protein to 70 000U/mg of protein). In addition, the same subject exhibited a constant proportion of Hb F synthesized in culture over a period of time up to 6 months. A positive correlation exists between the proportion of Hb F in culture and that of F cells present in the blood, with the exception of two subjects. Such findings suggest that Hb F in culture is a characteristic of each individual and that this reactivation often represents an amplification of the Hb F synthesis in vivo.

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.