四川遂宁地区献血者G-6-PD调查及进食蚕豆对蚕豆病儿输血的影响

应用改良四唑氮兰法对2483名献血者进行红细胞G-6-PD调查,G-6-PD缺乏率为8.3％,其中显著缺乏率为2.1％。建立献血者G-6-PD调查档案,防止蚕豆病儿输入缺乏G-6-PD的血液,提高了输血安全。观察献血者进食蚕豆后不同时间(2～4小时,12～24小时,2～3天)采血对蚕豆病儿输血的影响,各观察组临床症状与外周血Hb的恢复、G-6-PD活性的改变和对照组比较无明显差别,各组均未发现再溶血病例。提示蚕豆病儿在急性溶血后“不应期”内输入进食了蚕豆的献血者的血液无明显不良影响。     

新生儿ABO溶血病并红细胞葡萄糖-6-磷酸脱氢酶缺乏症临床对比分析

目的 探讨新生儿ABO溶血病、红细胞葡萄糖-6-磷酸脱氢酶(G-6-PD)缺乏症及两者合并患儿的临床特点.方法 对160例新生儿ABO溶血病(ABO组)、219例G-6-PD缺乏症(G6PD组)、52例新生儿ABO溶血病并G-6-PD缺乏症(ABO+G617D组)3组临床相关指标进行对比分析.结果 G6PD组血红蛋白[(159.7±24.9)g/L]高于ABO组[(150.2±23.0)g/L]和ABO+G6PD组[(149.2±22.8)g/L],差异均有统计学意义(P均<0.01);血清总胆红紊高于ABO组[(419.0±152.9)μmol/L与(355.4±113.2)μmol/L],差异有统计学意义(P<0.01);黄疸消退时间较ABO组长[(9.4±2.3)d与(8.1±2.2)d],差异有统计学意义(P<0.01).ABO+G6PD组黄疸消退时间[(12.0±2.7)d]、光疗时间[(43.2±16.0)h]、光疗次数[(3.5±1.2)次]均长或多于ABO组[(8.1.4-2.2)d、(36.1 4-15.9)h、(2.6±1.2)次]及其G6PD组[(9.4±2.3)d、(37.6±17.3)h、(2.8 4-1.3)次],差异均有统计学意义(P均<0.05).G6PD组胆红素脑病(16.O%)、低钙血症发生率(32.9%)高于ABO组(6.9%、20.0%),差异有统计学意义(P<0.05);而其贫血发生率(23.3%)则低于ABO组(40.0%)及其ABO+G6PD组(51.9%),差异有统计学意义(P<0.01).结论 新生儿ABO溶血病并G-6-PD缺乏症时,黄疸出现时间、黄疸程度、胆红素脑病发生率与新生儿ABO溶血病、G-6-PD缺乏症差异无显著性,但黄疸消退时间更长,黄疸更易反复.G-6-PD缺乏症与新生儿ABO溶血痛相比,黄疸程度更重,退黄时间更长,更易发生胆红素脑病,但贫血发生率更低.     

Evaluation of glucose-6-phosphate dehydrogenase activity in two different ethnic groups using a kit employing the haemoglobin normalization procedure

AIM: Correct evaluation of Glucose-6-Phosphate Dehydrogenase (G-6-PD) activity of two ethnic groups using a fully quantitative kit with a simultaneous Hemoglobin Normalization (Hb Normalization) procedure. DESIGN AND METHODS: Two groups of mothers and their healthy full term newborns of Greek (n = 1.166) and Albanian (n = 818) origin were tested for their G-6-PD activity employing a direct normalization protocol. RESULTS: Greek mothers and newborns showed a higher prevalence for G-6-PD deficiency as compared to those of Albanian origin. Males of G-6-PD deficient mothers confirmed the efficacy of the method. CONCLUSION: A fully quantitative G-6-PD kit employing Hb Normalization is essential for the correct classification of G-6-PD activity, both in male and female subjects.     

新生儿葡萄糖-6-磷酸脱氢酶缺乏症的筛查与分析

目的通过对新生儿葡萄糖-6-磷酸脱氢酶（glucose-6-phosphate dehydrogenase,G-6-PD）缺乏症的筛查及临床分析,了解桂平市新生儿G-6-PD缺乏情况及G-6-PD缺乏幼儿与高胆红素血症的相关性。方法对2010年7月至2011年7月在该院出生的3 402例新生儿进行G-6-PD测定,统计分析G-6-PD缺乏情况,并跟踪回访新生儿至出生后第10天,如果出现黄疸应立即采血测定胆红素,对新生儿高胆红素血症的发生率进行比较分析。结果新生儿G-6-PD缺乏症发病率为10.35%（352/3 402）,男婴G-6-PD缺乏率为14.28%（264/1 849）;女婴G-6-PD缺乏率为5.66%（88/1 553）。G-6-PD缺乏幼儿高胆红素血症的发生率为25.3%,明显高于G-6-PD正常新生儿的2.6%（P〈0.01）。结论广西桂平市是G-6-PD缺乏症的高发区,对G-6-PD缺乏症的筛查非常有意义,能有效提示医生谨慎用药和指导患儿避免接触诱因,预防溶血的发生,提高该地区人群的健康素质。     

Genetic diversity of the “Mediterranean” glucose-6-phosphate dehydrogenase deficiency phenotype

Genetic diversity of the "Mediterranean" phenotype of G-6-PD (glucose-6-phosphate dehydrogenase) deficiency was revealed when detailed studies were performed on blood specimens from 79 Greek males with G-6-PD levels 0-10% of normal. Four different mutants were found to be responsible for the severely deficient phenotypes: two mutants. G-6-PD U-M (Union-Markham) and G-6-PD Orchomenos, were distinguishable by electrophoresis, while the other two. G-6-PD Athens-like and G-6-PD Mediterranean, were distinguishable on the basis of their kinetic characteristics. Of the kinetic tests applied, the most useful for differentiating the variants were those measuring utilization rates of the analogue substrates deamino-NADP, 2-deoxyglucose-6-phosphate, and galactose-6-phosphate. Among unrelated males with severe G-6-PD deficiency, the relative frequencies of the four variants were: G-6-PD U-M. 5%; G-6-PD Orchomenos, 7%; G-6-PD Athens-like, 16%; G-6-PD Mediterranean, 72%. Genetic, biochemical, and clinical implications of the findings are discussed.     

Lactate dehydrogenase, glucosephosphate dehydrogenase, glutathione reductase and adenosine triphosphatase activities in the erythrocytes of patients with acute viral hepatitis

Some indices of erythrocyte metabolism (EM): activity of lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G-6-PD), glutathione reductase (GR) and common adenosinetriphosphatase (ATPase) activity were studied in 102 patients with acute viral hepatitis (AVH). The suppression of erythrocyte enzymatic activity (EE) was revealed. It was most noticeable at the peak of average and severe AVH. In a decrease of jaundice and during reconvalescence G-6-PD, GR and ATPase activity reduced up to the control level. The suppression of LDH activity was more noticeable, maintained at discharge and was of prognostic value in investigation at early periods of disease in cases of prolonged reconvalescence. Changes in EE activity showed correlation with indices of liver function (levels of certain bilirubin fractions and transaminase activity). In cases of developing deficiency of erythrocyte G-6-PD activity there was a high correlation between a degree of cytolysis and the suppression of erythrocyte LDH activity. The importance of erythrocyte metabolic derangements revealed in AVH pathogenesis was discussed.     

Intravascular hemolysis in aluminium phosphide poisoning.

Intravascular hemolysis is most often secondary to exposure to a variety of drugs or infections, and usually occurs in patients who are deficient in glucose-6-phosphate dehydrogenase (G-6-PD) enzyme. Aluminium phosphide, a fumigant widely used in India, has been reported to produce intravascular hemolysis in only one patient who also had concomitant G-6-PD deficiency. This report describes the occurrence of intravascular hemolysis with aluminium phosphide poisoning in a patient with normal G-6-PD levels. This is of significance as jaundice in patients with this poisoning is often attributed to hepatic damage alone.     

不同G-6-PD活性新生儿光疗时氧自由基的实验室检测结果分析

目的通过分析不同G-6-PD活性新生儿光疗时氧自由基的实验室检测结果的特点,为临床治疗新生儿高胆红素血症提供参考。方法对2001年6月~2003年12月该院新生儿科收治的诊断为高胆红素血症未经治疗的足月新生儿120例的实验室资料进行分析。结果光疗前干预组、对照组和正常组各指标比较,G-6-PD缺乏高胆红素血症光疗前已存在溶血、贫血,抗氧化能力下降、氧自由基增高及脂质过氧化损害,干预组与对照组间各检测值无显著性差异,有可比性。维生素E减轻G-6-PD缺乏时高胆红素血症光疗时脂质过氧化损伤,防止溶血和贫血加剧。结论光疗可致抗氧化能力下降,脂质过氧化损伤致G-6-PD缺乏时光疗者溶血更突出,维生素E干预更有效。     

Association of Naphthalene with Acute Hemolytic Anemia

OBJECTIVES: To describe the prevalence and severity of naphthalene-associated hemolysis (NA1) and infection-associated hemolysis (IAH) in children with glucose-6-phosphate dehydrogenase (G6-PD) deficiency. To survey the rationale for naphthalene-containing moth repellent (mothball) use in the study population and to compare this with that of a more diverse population. METHODS: A ten-year retrospective chart review of 160 patients with G-6-PD deficiency and/or anemia and an analysis of 24 hospitalized African-American children with an episode of acute hemolysis associated with G-6-PD deficiency were conducted. The parents of 330 children cared for in the pediatric emergency departments (EDs) of two tertiary care centers were questioned regarding domestic mothball (naphthalene) use. RESULTS: Fourteen of 24 (58.3%) of the children identified with G-6-PD deficiency presented with hemolysis associated with exposure to naphthalene-containing moth repellents. The remaining ten had IAH. Seventy-nine percent of the NAH group required transfusion, compared with 60% of the IAH group. Mothballs were reportedly used by 27% of the families surveyed in one inner-city population with a 2-13% incidence of G-6-PD deficiency and by 15% in a more culturally diverse city. The main reported motivation for use was the fresh scent, not as a moth repellent. CONCLUSIONS: Mothballs are used for previously unrecognized reasons. Naphthalene-containing mothballs can pose a hematologic threat to vulnerable populations.     

广西地区新生儿疾病筛查结果回顾性分析

目的：了解2009～2012年广西地区新生儿疾病筛查情况及确诊率。方法通过检测促甲状腺素（TSH）筛查甲状腺功能减低症（CH）、苯丙氨酸（PHe）筛查苯丙酮尿症（PKU）、17-羟孕酮（17-OHP）筛查先天性肾上腺皮质增生症（CAH）、葡萄糖-6-磷酸脱氢酶（G-6-PD）筛查G-6-PD缺乏症,对初次筛查阳性的患儿进行及时召回并确诊。结果2009年1月至2012年12月广西新生儿疾病筛查中心合作单位的新生儿筛查率呈逐年上升趋势且CH、PKU、CAH、G-6-PD初次筛查阳性患儿召回率及确诊率存在差异。结论新生儿筛查可以在早期发现CH、PKU、CAH、G-6-PD缺乏症患儿,对其早期进行干预可以防止其发病从而降低对其智力及生长发育的影响,对提高人口素质有重要意义。     

Studies in hemolysis in glucose-6-phosphate dehydrogenase-deficient African American neonates

BACKGROUND: The role of hemolysis in the mechanism and prediction of hyperbilirubinemia was contrasted between glucose-6-phosphate dehydrogenase (G-6-PD)-deficient and -normal African American neonates. METHODS: Corrected end tidal carbon monoxide (ETCOc) values from the subset of male neonates born to non-smoking African American mothers, drawn from a previously published study, were analyzed. The relationship between ETCOc and bilirubin values, the latter represented as percentiles on the hour of life specific bilirubin nomogram, was determined. Hyperbilirubinemia was defined as any bilirubin value > or =95th percentile for hour of life. RESULTS: 18.6% of 59 G-6-PD-deficient neonates developed hyperbilirubinemia, compared with 7.5% of 362 controls (relative risk 2.50, 95% confidence interval 1.31 to 4.76). As reported, ETCOc values (median, interquartile range) were significantly higher among G-6-PD-deficient neonates than controls (2.4 [2.0-2.9] vs. 2.1 [1.7-2.5] ppm, p<0.001. However, higher ETCOc values were limited to those G-6-PD-deficient neonates with lower bilirubin percentiles: among those whose bilirubin value did not exceed the 95th percentile ETCOc was 2.30 [2.00-2.85] vs. 2.00 [1.70-2.40] ppm in controls, p=0.001. In contrast, among the hyperbilirubinemic neonates ETCOc values were similar between G-6-PD-deficient neonates and controls: 2.7 [2.03-3.33] vs. 2.6 [2.33-3.45] ppm, p=0.9. In the G-6-PD-deficient neonates ETCOc > or =75th percentile contributed no additional predictive value for hyperbilirubinemia (likelihood ratio 1.8). CONCLUSIONS: G-6-PD-deficient African American neonates have increased hemolysis and increased rate of hyperbilirubinemia, but the hemolysis is neither a predominant factor in the pathogenesis of hyperbilirubinemia nor is it predictive of hyperbilirubinemia, over and above the already increased risk conferred by G-6-PD deficiency.     

Life and Death of Glucose-6-Phosphate Dehydrogenase (G6PD) Deficient Erythrocytes – Role of Redox Stress and Band 3 Modifications

Summary

G6PD catalyzes the first, pace-making reaction of pentosephosphate cycle (PPC) which produces NADPH. NADPH maintains glutathione and thiol groups of proteins and enzymes in the reduced state which is essential for protection against oxidative stress. Individuals affected by G6PD deficiency are unable to regenerate reduced glutathione (GSH) and are undefended against oxidative stress. G6PD deficiency accelerates normal senescence and enhances the precocious removal of chronologically young, yet biologically old cells. The term hemolytic anemia is misleading because RBCs do not lyse but are removed by phagocytosis. Acute hemolysis by fava bean ingestion in G6PD deficient individuals (favism) is described being the best-studied natural model of oxidant damage. It bears strong analogies to hemolysis by oxidant drugs or chemicals. Membrane alterations observed in vivo during favism are superimposable to changes in senescent RBCs. In summary, RBC membranes isolated from favic patients contained elevated amounts of complexes between IgG and the complement fragment C3b/C3c and were prone to vesiculation. Anti-band 3 IgG reacted to aggregated band 3-complement complexes. In favism extensive clustering of band 3 and membrane deposition of hemichromes were also observed. Severely damaged RBCs isolated from early crises had extensive membrane cross-bonding and very low GSH levels and were phagocytosed 10-fold more intensely compared to normal RBCs.KeyWords: G6PD, G6PD deficiency, Band 3, Hemolysis, Favism     

Glucose-6-phosphate dehydrogenase activity in term and near-term, male African American neonates

BACKGROUND: We determined values for glucose-6-phosphate dehydrogenase (G-6-PD) activity in African American neonates. METHODS: G-6-PD activity was measured on umbilical cord blood from term and near-term healthy, male neonates. Neonates were stratified according to the number of neonates for each numerical unit of G-6-PD activity. Corrected end tidal carbon monoxide (ETCOc), a non-invasive index of hemolysis, was performed on each neonate. At least one predischarge transcutaneous bilirubin determination was performed. RESULTS: Five hundred neonates were studied. Two subpopulations were apparent, with no overlap between the subgroups. Mean value for the 64 (12.8%) infants with the lower values (G-6-PD deficient) was 2.7+/-1.1 U/g Hb, range 0.4-6.6 U/g Hb, while that for the 436 neonates with the higher values (G-6-PD normal) was 21.8+/-2.9 U/g Hb, range 14.5-33.8 U/g Hb. No significant differences in activity were noted between those neonates <37 weeks gestational age and those >37 weeks. Enzyme activity in the lower range in both groups was not related to the development of hyperbilirubinemia. G-6-PD enzyme activity did not correlate with ETCOc values either for the entire cohort or for the individual subsets. CONCLUSIONS: G-6-PD-deficient neonates formed a separate subgroup from those with normal enzyme activity. The data supplied should facilitate interpretation of G-6-PD test results.     

Detection of glucose-6-phosphate dehydrogenase deficiency in erythrocytes: a spectrophotometric assay and a fluorescent spot test compared with a cytochemical method

The results of a quantitative spectrophotometric enzyme assay, a fluorescent spot test and a cytochemical assay for glucose-6-phosphate dehydrogenase deficiency were compared systematically. The high sensitivity of the spectrophotometric assay and the fluorescent spot test in the detection of severely deficient individuals was confirmed. For the detection of heterozygote females, however both tests were unreliable; the sensitivities of the fluorescent spot test and the spectrophotometric assay being 32% and 11% respectively. Specificities for both tests were high (99%). Introduction of the ratio of glucose-6-phosphate dehydrogenase and pyruvate kinase (G-6-PD/PK ratio) activities increased the sensitivity of the spectrophotometric assay to nearly 100%. It is concluded that the fluorescent spot test should be used for the diagnosis of G-6-PD deficiency in developing countries; whereas if spectrophotometric enzyme assays are available, the G-6-PD/PK ratio should always be performed. In cases where the ratio is less than 0.70, cytochemical analysis is indicated.     

Prolonged jaundice in newborns is associated with low antioxidant capacity in breast milk

Abstract

In breastfeeding newborns who are otherwise healthy, the mechanism of prolonged jaundice remains unclear. The aim of this study was to investigate relations between prolonged jaundice and oxidative parameters in breast milk. Full-term, otherwise healthy newborns with jaundice lasting more than 2 weeks were enrolled prospectively in the study. As a control group, newborns in the same age group but without prolonged jaundice were selected. All newborns in the study were exclusively breastfed. In the newborns with prolonged jaundice, investigations of the etiology of the jaundice included complete blood count, peripheral blood smear, blood typing, direct Coombs test, measurement of serum levels of total and direct bilirubin, tests for liver and thyroid function (TSH, free T4, total T4), urine culture and measurement of urine reducing substances, and determination of glucose 6 phosphate dehydrogenase enzyme levels. Breast milk was collected from the mothers of the newborns in both groups. The antioxidant status of the breast milk was assessed via determination of total antioxidant capacity (TAC). Oxidative stress was also assessed in breast milk by measurement of total oxidation status (TOS) and calculation of the oxidative stress index (OSI). The prolonged jaundice group differed significantly from the control group in terms of mean TAC and OSI (p < 0.001), but not in terms of TOS. In conclusion, in the breast milk of mothers of newborns with prolonged jaundice, oxidative stress was found to be increased, and protective antioxidant capacity was found to be decreased.     

An update on the prevalence of glucose-6-phosphate dehydrogenase deficiency and neonatal jaundice in Tehran neonates

OBJECTIVES: The aim of this study was to screen newborns in Tehran for glucose-6-phosphate dehydrogenase (G6PD) deficiency in relation to hyperbilirubinemia and jaundice. DESIGN AND METHODS: We performed quantitative and qualitative red blood cell (RBC) G6PD assays in cord blood of 2000 male and female at-term neonates. Observations for jaundice and bilirubin determination were made in G6PD-deficient and normal groups. Those with severe jaundice were treated with phototherapy or exchange transfusion. RESULTS: Our results showed that 2.1% (3.6% of males and 0.6% of females) was G6PD-deficient. Those with severe jaundice and hyperbilirubinemia (160 normal and 17 G6PD-deficient) were hospitalized and treated with phototherapy or exchange transfusion. Bilirubin levels in G6PD-deficient neonates were somewhat higher compared to G6PD-normal babies (18.8 +/- 2.4 mg/dl [321.5 +/- 41 micromol/l] vs. 15.7 +/- 3.2 mg/dl [268.5 +/- 54.7 micromol/l]; P < 0.05). G6PD activity was significantly lower in G6PD-deficient group than in the normal group (2.1 +/- 0.7 vs. 12.5 +/- 5.0 U/g Hb; P < 0.001). CONCLUSION: This study shows that the incidence of G6PD deficiency in newborns of Tehran is 2.1%, which is relatively high, and also hyperbilirubinemia and jaundice are approximately 3-fold higher in G6PD-deficient group than in the G6PD-normal group (51% vs. 16%). This emphasizes the necessity of neonatal screening on cord blood samples of both sexes for G6PD deficiency and the need to watch closely for development of hyperbilirubinemia.     

Phosphate compounds in the erythrocytes of newborns with ABO systems haemolytic disease.

The following phosphate compounds of the erythrocyte acid-soluble fraction were subjected to chromatographic separation: ADP, ATP, adenylo-diphosphoglycerate, 2,3-diphosphoglycerate, hexose monophosphate, hexose diphosphate. In each of the fractions total phosphorus, and in fraction II inorganic phosphorus, were estimated. The material was derived from ten newborns with haemolytic disease as a result of ABO incompatability and from ten full-term healthy newborns, just after birth. The concentration of the compounds assayed, except for 2,3-DPG (the values in both groups were similar) was higher in the erythrocytes from affected newborns, but lower than that found in the material derived from the newborns with Rh incompatibility. It is suggested that the metabolism of erythrocytes of the newborns with haemolytic ABO disease may be somewhat different from that in Rh incompatibility cases because in the former the haemolysis is weaker, the anaemia is less pronounced and the tissue hypoxia is of a smaller degree.     

Immunoglobulin and glucose-6-phosphate dehydrogenase as markers of cellular origin in Burkitt lymphoma

Two independent marker systems, G-6-PD isoenzymes and cell membrane-associated IgM, were used to trace the cellular origin of Burkitt lymphoma. Application of the G-6-PD system is dependent upon the fact that, in accordance with inactivity of one X chromosome in each somatic cell, females heterozygous for the usual B gene (Gd ^B) at the X-linked G-6-PD locus and the variant allele Gd ^A (or Gd ^A-) have two types of cells. Gd ^B is active in one cell population, which consequently produces B type enzyme; in the other population Gd ^A is active, producing the variant A enzyme. Therefore, tumors with a clonal origin in a Gd ^B/Gd ^A heterozygote should exhibit only one enzyme type (B or A) whereas those with multicellular origin may show both A and B enzymes. Utilization of the immunoglobulin system is based upon the supposition that in lymphoid neoplasms with clonal origin either all or none of the tumor cells should have surface-associated IgM and κ-reactivities. 33 of 34 relatively homogeneous (with respect to content of neoplastic cells) individual Burkitt tumors from 19 G-6-PD heterozygotes had single enzyme phenotypes. Similarly, of 95 tumors tested, 92 consisted essentially of IgM(+) or (-) cells. Two neoplasms could not be definitely classified and one tumor had two cell populations. These data suggest a clonal origin for most Burkitt tumors, but the one neoplasm with a double G-6-PD phenotype (A/B) and the one tumor that had two populations of cells with respect to surface IgM, could have originated from multiple cells. G-6-PD was determined in each of two tumors from seven heterozygotes and in all cases both tumors had the same single enzyme phenotype. Surface-associated IgM was tested in four tumors from one patient, three from another, and in two neoplasms from 11 patients. With one exception, all tumors from the same patient were concordant with respect to IgM. These findings suggest that the entire disease has a clonal origin, i.e., it emerges at one focus and then spreads to other parts of the body. Cells from 36 recurrent neoplasms were typed for G-6-PD (in heterozygotes) and/or IgM. In one previously reported patient, initial and recurrent tumors were discordant for G-6-PD. Two other patients had IgM phenotypes in recurrences that were discordant with those found in their initial tumors. Phenotypes from three of nine relapses which occurred after 5 mo were discordant for G-6-PD or IgM but no discordance was detected among 27 earlier recurrences. Thus, some "late" recurrences may be due to emergence of "new" maligant cell lines whereas most early relapses are due to reemergence of the original malignant clones. The probable unicellular origin of Burkitt lymphoma and the findings in tumor recurrences are discussed in terms of the disease''s putative viral etiology.     

Glucose-6-Phosphate Dehydrogenase (G-6-PD) Hamburg, a New Variant with Chronic Nonspherocytic Haemolytic Anaemia

Abstract. A new variant of G-6-PD with chronic nonspherocytic haemolytic anaemia and very low activity, named G-6-PD Hamburg, was partially purified and biochemically characterized. It was found to have very high lability, an unusually high Km for G-6-P (2000 μM), increased utilization rates for 2-desoxy G-6-P (133%) and galactose-6-phosphate (87%) and an abnormal pH-activity curve. The electrophoretic mobility seemed to be normal. The leukocytes also revealed diminished G-6-PD activity. No impairment of bactericidal activity of neutrophilic granulocytes, as shown by a normal nitroblue tetrazolium reduction, could be demonstrated.     

Polycythemia Vera: FURTHER IN VITRO STUDIES OF HEMATOPOIETIC REGULATION

Further in vitro studies of hematopoietic regulation were carried out in two patients with polycythemia vera who were also heterozygotes (Gd^B/Gd^A) for glucose-6-phosphate-dehydrogenase (G-6-PD). While only G-6-PD type A was detectable in circulating erythrocytes, granulocytes and platelets, cultures of peripheral blood and marrow from one patient revealed a substantial number of G-6-PD type B erythroid burst-forming units (BFU-E) and granulocyte/macrophage colony-forming units. Detailed analysis demonstrated: (a) where detectable, normal BFU-E and granulocyte/macrophage colony-forming units were found with similar frequencies; (b) the same frequencies for normal progenitors characterized cultures of peripheral blood and marrow; (c) inhibition of normal erythroid differentiation between BFU-E and the more mature erythroid colony-forming unit; (d) a decline in the prevalence of normal colony-forming units with time, suggesting that disease progression is associated with further suppression of normal hematopoiesis by products of the abnormal clone.