Comprehensive analysis of mitochondrial and nuclear DNA variations in patients affected by hemoglobinopathies: A pilot study

The hemoglobin disorders are the most common single gene disorders in the world. Previous studies have suggested that they are deeply geographically structured and a variety of genetic determinants influences different clinical phenotypes between patients inheriting identical β-globin gene mutations. In order to get new insights into the heterogeneity of hemoglobin disorders, we investigated the molecular variations on nuclear genes (i.e. HBB, HBG2, BCL11A, HBS1L and MYB) and mitochondrial DNA control region. This pilot study was carried out on 53 patients belonging to different continents and molecularly classified in 4 subgroup: β-thalassemia (β+/β+, β0/β0 and β+/β0)(15), sickle cell disease (HbS/HbS)(20), sickle cell/β-thalassemia (HbS/β+ or HBS/β0)(10), and non-thalassemic compound heterozygous (HbS/HbC, HbO-Arab/HbC)(8). This comprehensive phylogenetic analysis provided a clear separation between African and European patients either in nuclear or mitochondrial variations. Notably, informing on the phylogeographic structure of affected individuals, this accurate genetic stratification, could help to optimize the diagnostic algorithm for patients with uncertain or unknown origin.

Humoral Immune Reconstitution Kinetics after Allogeneic Hematopoietic Stem Cell Transplantation in Children: A Maturation Block of IgM Memory B Cells May Lead to Impaired Antibody Immune Reconstitution

Although T cell immune reconstitution after allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been well studied, long-term B cell immune reconstitution remains less characterized. We evaluated humoral immune reconstitution among 71 pediatric allo-HSCT recipients. Although tetanus toxoid antibody levels were normal at 1 year after allo-HSCT, antipolysaccharide carbohydrate antibodies remained persistently low for up to 5 years. While naive B cell counts normalized by 6 months, IgM memory B cell deficiency persisted for up to 2 years (P = .01); switched memory B cell deficiency normalized by 1 year after allo-HSCT. CD4⁺ T cell immune reconstitution correlated with that of switched memory B cells as early as 6 months after allo-HSCT (r = .55, P = .002) but did not correlate with IgM memory B cells at any time point after allo-HSCT. Taken together, this suggests that allo-HSCT recipients have impaired antibody immune reconstitution, mainly due to IgM memory B cell maturation block, compared with more prompt T cell-dependent switched memory cell immune reconstitution. We further explored other factors that might affect humoral immune reconstitution. The use of total body irradiation was associated with lower naive B cells counts at 6 months after HSCT (P = .04) and lower IgM (P = .008) and switched (P = .003) memory B cells up to 2 years. Allo-HSCT recipients with extensive chronic graft-versus-host disease had lower IgM memory B cell counts (P = .03) up to 2 years after allo-HSCT. The use of cord blood was associated with better naive (P = .01), IgM (P = .0005), and switched memory (P = .006) B cells immune reconstitution. These findings may inform future prophylaxis and treatment strategies regarding risk of overwhelming infection, graft-versus-host disease, and post-allogeneic HSCT revaccination.

Potential Impact of Co-Infections and Co-Morbidities Prevalent in Africa on Influenza Severity and Frequency: A Systematic Review

Infectious diseases and underlying medical conditions common to Africa may affect influenza frequency and severity. We conducted a systematic review of published studies on influenza and the following co-infections or co-morbidities that are prevalent in Africa: dengue, malaria, measles, meningococcus, Pneumocystis jirovecii pneumonia (PCP), hemoglobinopathies, and malnutrition. Articles were identified except for influenza and PCP. Very few studies were from Africa. Sickle cell disease, dengue, and measles co-infection were found to increase the severity of influenza disease, though this is based on few studies of dengue and measles and the measles study was of low quality. The frequency of influenza was increased among patients with sickle cell disease. Influenza infection increased the frequency of meningococcal disease. Studies on malaria and malnutrition found mixed results. Age-adjusted morbidity and mortality from influenza may be more common in Africa because infections and diseases common in the region lead to more severe outcomes and increase the influenza burden. However, gaps exist in our knowledge about these interactions.

Diagnosis and management of rare congenital nonimmune hemolytic disease

Rare, congenital nonimmune hemolytic disorders of the erythrocyte, although uncommon, are important causes of anemia in the child and adult. These are a heterogeneous group of diseases that disrupt normal erythrocyte structure and function in varying ways. Predominant are abnormalities of hemoglobin stability, defects of erythrocyte metabolism, and disorders of erythrocyte hydration. Unstable hemoglobinopathies may lead to chronic or episodic hemolysis. Perturbation of critical enzymes of the Embden-Meyerhof pathway lead to altered erythrocyte metabolism and chronic hemolysis. Disorders of erythrocyte hydration are an under-recognized cause of hemolytic anemia. Beyond pathophysiologic mechanisms of disease, clinical, laboratory, and genetic heterogeneity characterize this group of disorders. Often, they are underdiagnosed or misdiagnosed. This review discusses pathophysiology, inheritance, clinical findings, laboratory manifestations, and management considerations in several rare nonimmune hemolytic diseases including the unstable hemoglobins, disorders of erythrocyte metabolism, and abnormalities of erythrocyte hydration.

Observations on the ultrastructure of sinusoids and reticular cells in human bone marrow

The ultrastructural characteristics of sinusoids in human bone marrow were generally similar to those previously reported in the rat. However, human sinusoids differed from rat sinusoids in displaying frequent tight junctions between adjacent overlapping or interdigitating endothelial cells. In both species, large areas of the sinusoidal walls were devoid of much subendothelial connective tissue and of an outer adventitial cell layer. The marrow sinusoids of humans resembled those of rabbits and rats in that processes of macrophage cytoplasm protruded through endothelial cells into the sinusoidal lumen; thin veils derived from such processes were apposed over the inner surfaces of some endothelial cells. Features observed in pathological human marrow not noted in rodent marrow are the phagocytosis of extruded erythroblast nuclei and of abnormal erythroblasts by perisinusoidal adventitial cells (reticular cells) and the presence of large secondary lysosomes and siderosomes in sinusoidal endothelial cells. When compared with mouse bone marrow, human bone marrow contained very few non-phagocytic reticular cells that were unassociated with sinusoids and other blood vessels. There were no absolute ultrastructural differences between perisinusoidal adventitial cells, intersinusoidal non-phagocytic reticular cells and macrophages lacking phagosomes or containing only a few small phagosomes. Consequently, on some occasions, these cell types could not be reliably identified from the study of a single thin section. Extracellular reticulin fibres were found adjacent both to non-phagocytic reticular cells and to macrophages. Mitosis was observed in macrophages, albeit very rarely.

Hematological abnormalities in patients with distal renal tubular acidosis and hemoglobinopathies

Mutations of the human SLC4A1 gene encoding erythroid and kidney isoforms of anion exchanger 1 (AE1, band 3) result in erythrocyte abnormalities or distal renal tubular acidosis (dRTA) and such mutations are observed in Southeast Asia, where hemoglobinopathies are prevalent. Genetic and hematological studies in 18 Thai patients with dRTA have shown that 12 of them (67%) carried SLC4A1 mutations (7 G701D/G701D, 3 SAO/G701D, and 2 G701D/A858D). Of these 12 patients, three had homozygous G701D/G701D and heterozygous Hb E; one compound heterozygous SAO/G701D and heterozygous alpha(+)-thalassemia; and one compound heterozygous G701D/A858D and heterozygous Hb E. Of 6 patients without SLC4A1 mutation, two each carried heterozygous or homozygous Hb E and one of the latter also had Hb H disease (--(SEA)/-alpha(4.2)). The blood smears of patients with homozygous G701D/G701D showed approximately 25% ovalocytes. Strikingly, the patients with coexistence of homozygous G701D/G701D and heterozygous Hb E had 58% ovalocytes. Similarly, the patients who had compound heterozygous SAO/G701D showed 49% ovalocytes, but the patient with coexistence of compound heterozygous SAO/G701D and heterozygous alpha(+)-thalassemia had 70% ovalocytes. Our previous study has shown that under metabolic acidosis, the patients with homozygous G701D/G701D or compound heterozygous SAO/G701D had reticulocytosis, indicating compensated hemolysis. A patient with compound heterozygous SAO/G701D and heterozygous alpha(+)-thalassemia presented with hemolytic anemia and hepatosplenomegaly which was alleviated by alkaline therapy. Taken together, the coexistence of both homozygous or compound heterozygous SLC4A1 mutations and hemoglobinopathy has a combined effect on red cell morphology and degree of hemolytic anemia, which is aggravated by acidosis.

Cytomorphologic signs of severe pernicious anemia obscured in a patient with heterozygous hemoglobin Stanleyville II

Here, we report a rare coincidence of heterozygous hemoglobinopathy (Hb) Stanleyville II and severe pernicious anemia due to autoimmune gastritis. Hb Stanleyville II is characterized by a single base exchange (AAC-->AAA) resulting in a substitution Asn --> Lys at position 78 of hemoglobin alpha2-chain. Under normal conditions this hemoglobinopathy does not cause any symptoms even if present as homozygous variant. However, in our case diagnosis of pernicious anemia was hampered by the absence of typical erythrocytic macrocytosis and hyperchromasia. In addition, interpretation of bone marrow smears was difficult as characteristic findings for pernicious anemia were little pronounced. All known reasons for the absence of typical cytomorphologic signs in pernicious anemia as underlying iron deficiency and thalassemia could be excluded.

Large-scale population genetic analysis for hemoglobinopathies reveals different mutation spectra in central Greece compared to the rest of the country

We have undertaken a large population screening study to identify the molecular basis of hemoglobinopathies in the central Greece region. A total of 845 unrelated beta-thalassemia patients and alpha-, beta-, and deltabeta-thalassemia carriers have been recruited and screened for mutations in the alpha- and beta-globin gene clusters. The alpha(-MED) deletion and the Turkish inversion/deletion are the most frequent genetic rearrangements leading to alpha- and deltabeta-thalassemia respectively, contrary to the situation in the rest of the country, while the beta -101 (C>T) promoter mutation is surprisingly frequent in the central part of Greece. Our data indicate that determination of mutation frequencies in different regions is vital for accurate provision of genetic services and counseling and for precise estimation of genetic diversity.

Gold nanoparticle-based tool to study protein conformational variants: implications in hemoglobinopathy

The size of gold nanoparticles is shown here to gradually decrease if it is allowed to grow on a protein template, and the protein is subjected to unfolding by a nonionic denaturant. The correlation between size of the gold nanoparticle formed and the plasmon frequency observed remains linear, except at stages where protein folding intermediates are formed. Higher population of exposed tyrosine residues, number of sulfhydryl groups of the protein, and the overall exposition of the inner hydrophobic core may lead to the generation of smaller particles. The method provides a simple colorimetric sensing of protein conformation and has been tested for both nonheme and heme proteins (hemoglobin and bovine serum albumin). Similarly, protein variants with defects in folding (caused by subunit misassembly or mutation) can also be classified. Possible application of this approach in hemoglobinopathy (e.g., thalassemia carrier detection) is discussed in the text.

[Hemoglobinopathies--clinical symptoms and diagnosis of thalassemia and abnormal hemoglobins]

Haemoglobinopathies constitute entities that are generated by either an abnormal haemoglobin or thalassaemias. While abnormal haemoglobins are caused by a qualitative structural abnormality of the haemoglobin molecule, thalassaemias result by diminished synthesis of the globin chain. Due to increased immigration from Asia, Africa and the Mediterranean to Northern Europe, haemoglobin S, haemoglobin C, haemoglobin E are also encountered commonly in Switzerland, while other abnormal haemoglobins are rare, yet can cause clinically relevant symptoms. This include haemolysis, polyglobulia, cyanosis or a combination thereof Thalassaemia-syndroms constitute with two million affected individuals to the most prelevant monogenetic diseases worldwide. Due to migration into Switzerland, they are also found quite commonly among our patients with 10-15 per cent of all hypochromic, microcytic, anemia second only to iron deficiency. Importantly, thalassaemias and haemoglobinopathies can occur concomitantly sometimes even with a normal haemoglobin variant. This results in wide-spread presentations, making diagnosis and clinical judgement difficult. We describe in this article not only physiological mechanisms and clinical presentation but also propose a step-wise diagnostic algorithm including selective use of molecular biology methods.

Iron metabolism in the hemoglobin-deficit mouse: correlation of diferric transferrin with hepcidin expression

The iron requirements of the erythroid compartment modulate the expression of hepcidin in the liver, which in turn alters intestinal iron absorption and iron release from the reticuloendothelial system. We have taken advantage of an inherited anemia of the mouse (hemoglobin deficit, or hbd) to gain insights into the factors regulating hepcidin expression. hbd mice showed a significant anemia but, surprisingly, their iron absorption was not increased as it was in wild-type animals made anemic to a similar degree by dietary iron depletion. In wild-type mice hepatic hepcidin levels were decreased but in hbd animals a significant and unexpected increase was observed. The level of absorption was appropriate for the expression of hepcidin in each case, but in hbd mice did not reflect the degree of anemia. However, this apparent inappropriate regulation of hepcidin correlated with increased transferrin saturation and levels of diferric transferrin in the plasma, which in turn resulted from the reduced capacity of hbd animals to effectively use transferrin-bound iron. These data strengthen the proposal that diferric transferrin is a key indicator of body iron requirements.

Hb Bristol-Alesha presenting thalassemia-type hyperunstable hemoglobinopathy

Hemoglobin (Hb) Bristol-Alesha is caused by a GTG --> ATG mutation at codon 67 in the Hb beta chain, resulting in abnormal beta globin chains with mutated molecules from normal beta67 valine (Val) to beta67 methionine (Met) or beta67 aspartate (Asp). We describe a Japanese child with this rare hemoglobinopathy and a very unstable Hb molecule phenotype. The diagnosis of hemolytic anemia was made when the patient was 6 months of age. Development of marked splenomegaly necessitated red blood cell transfusions twice a month. After splenectomy when the patient was 4 years of age, laboratory findings of hemolytic anemia became more prominent. Specific abnormal Hb molecules initially were not detected, and the alpha/beta globin synthesis ratio was abnormal at 2.22. After splenectomy, we identified the presence of abnormal beta-globin chains with a beta67Val:beta67Met:beta67Asp molecule ratio of 74:11:15. We speculate that the high fraction of the beta67Met molecule in this patient, compared with that in previously reported cases, caused extreme Hb instability, which resulted in thalassemic hyperunstable hemoglobinopathy and very severe clinical findings.

Thalassemia and abnormal hemoglobin

Thalassemia and abnormal hemoglobins are common genetic disorders in Asia. Thalassemia is not only an important public health problem but also a socio-economic problem of many countries in the region. The approach to deal with the thalassemic problem is to prevent and control birth of new cases. This requires an accurate identification of the couple at high risk for thalassemia. However, the diagnosis of thalassemia carrier states need several tests which are not practical for screening the population at large. Recently we have used two simple laboratory tests to screen for potential thalassemia carriers and hemoglobin E individuals. There is also a new development in using the automatic HPLC to diagnose thalassemic diseases and the carriers. This system gives both qualitative and quantitative analysis of hemoglobin components in the same run with good precision and reproducibility. The system has been applied to study thalassemia and abnormal Hb in adult and cord blood. This system has enabled us to do both prenatal and postnatal diagnosis of thalassemia within the few minutes. However, none of these screening tests can accurately give specific diagnosis of the thalassemia genotype. Specific thalassemia mutation can be carried out by DNA analysis. Many DNA techniques have been used for point mutation detection and small deletion. For the last few years there is a development of DNA chip technology that has been applied for thalassemia mutation as well. Clinically, thalassemia is very heterogeneous in the manifestation. In spite of seemingly identical genotypes, severity of beta thalassemic patients can vary greatly. Heterogeneity in the clinical manifestation of beta thalassemic diseases may occur from the nature of beta globin gene mutation, alpha thalassemia gene interaction and difference in the amount of Hb F production which is partly associated with a specific beta globin haplotype. However, there is still some beta thalassemia cases that have a mild clinical symptom without those known genetic fators interaction suggesting that there are other additional factors responsible for the mildness of the disease.

Inherited haemoglobin disorders: an increasing global health problem

Despite major advances in our understanding of the molecular pathology, pathophysiology, and control and management of the inherited disorders of haemoglobin, thousands of infants and children with these diseases are dying through lack of appropriate medical care. This problem will undoubtedly increase over the next 20 years because, as the result of a reduction in childhood mortality due to infection and malnutrition, more babies with haemoglobin disorders will survive to present for treatment. Although WHO and various voluntary agencies have tried to disseminate information about these diseases, they are rarely mentioned as being sufficiently important to be included in setting health care priorities for the future. It takes considerable time to establish expertise in developing programmes for the control and management of these conditions, and the lessons learned in developed countries will need to be transmitted to those countries in which they occur at a high frequency.

Prenatal diagnosis of hemoglobinopathies

Hemoglobinopathies are the most frequent and severe inherited diseases worldwide. Prenatal diagnosis is an effective way of controlling severe hemoglobin disorders for which effective treatments are not yet available everywhere. It is a multidisciplinary process requiring knowledge of the spectrum of molecular defects and involving laboratory investigations and genetic counseling. Hematological screening for these disorders is simple, rapid, and reliable. Carrier screening in populations at risk and genetic counseling are part of a number of European health programs, offering many couples at risk the chance of having a healthy child. This article describes the current molecular biology techniques for prenatal diagnosis of hemoglobinopathies.

Intracellular Ca(2+)-containing vesicles in sickle cell disorders

The frequency of red blood cells harboring Ca(2+)-containing vesicles was determined in patients with various sickle cell disorders; vesicles were identified by microscopy after the cells were stained with the fluorescent probe chlortetracycline. Specimens from 49 patients were studied. The highest frequencies of vesicle-containing cells were observed in samples from adults with homozygous sickle cell (SS) disease and in patients with S beta zero and SS(-alpha/alpha alpha) thalassemias. The frequency of cells with vesicles was less elevated in patients with SS(-alpha/-alpha) thalassemia and in patients with SS disease (Saudi Arabia high hemoglobin F), whereas a normal low frequency of positive cells was seen in patients with sickle cell-hereditary persistence of fetal hemoglobin and in patients with sickle trait. Deoxygenation induced an increase in the number of vesicle-containing cells that was proportional to the frequency of such cells in the oxygenated population. The frequency of Ca(2+)-containing vesicles in sickle red cells is associated with the clinical, hematologic, or clinical and hematologic severity of the sickle cell disorder.

Hemoglobin Sabine [beta 91 (F7) Leu-->Pro]: occurrence in a Sardinian individual with hemolytic anemia and inclusion bodies

BACKGROUND

Hemoglobin (Hb) Sabine (beta 91 Leu-->Pro) is an unstable variant detected for the first time in a 16-year-old Scottish-English-German girl affected by moderately severe hemolytic anemia. A second case was described in a patient of Yugoslavian descent. We report another case of this Hb variant arising as a de novo mutation in a Sardinian patient.

METHODS

Definition of the mutation was obtained by DNA direct sequencing on amplified beta-globin gene, as well as by structural analysis of the hemoglobin variant.

RESULTS AND CONCLUSION

The patient presented a moderately severe hemolytic anemia with red blood cell inclusion bodies. Hemoglobin electrophoresis showed that quantitatively the abnormal fraction represented 9% of the total Hb amount. beta globin gene analysis revealed a single nucleotide substitution, T-->C, at codon 91, which gives rise to a leucine-->proline substitution. Structural analysis of the variant confirmed the amino acid substitution (Leu-->Pro) predicted by DNA sequencing.

Ophthalmologic complications in hemoglobinopathies

The various forms of sickle cell disease share the common feature of an abnormal globin chain that, under certain conditions such as hypoxia, results in the sickling of red blood cells and obstruction of blood vessels. The ophthalmic manifestations of sickle cell disease are present in various segments of the eye, which include the conjunctiva, iris, retina, and optic nerve. Patients with SC disease and SB thalassemia tend to have more severe ophthalmic complications than their counterparts with the more severe systemic form of sickle cell disease--SS disease. It is important for patients with sickle cell disease to have periodic examinations by ophthalmologists, because the early identification of peripheral retinal disease can be adequately treated, with preservation of vision. Without treatment, peripheral retinal changes can lead to retinal detachments and vitreous hemorrhages, which account for the majority of visual impairment in patients with sickle cell disease.

Cranial thickening in an Australian hominid as a possible palaeoepidemiological indicator

This paper describes the cranial thickening of a late Pleistocene hominid (Willandra Lakes Hominid 50) from Australia. The unusual development of the vault structures in this individual has few, if any, equals among other hominids or more recent populations from around the world. The vault morphology is, therefore, described in terms of a pathologically related condition associated with the modern haemolytic blood dyscrasias, typical of sickle cell anamia and thalassemia. A possible palaeoepidemiology for these genetic adaptations among early Australasian populations is proposed together with a discussion of similar changes observed in the vault of the Singa calvarium from the Sudan. It is tentatively suggested that the cranial thickening of the Australian hominid has its origins in some form of genetic blood disease and that if this diagnosis is correct, this individual provides a rare glimpse of human biological adaptation in the late Upper Pleistocene.

Effects of hemin on erythropoiesis

It is clear that in vitro hemin increases the number of blood BFU-E derived colonies from normal donors. This occurs with sickle donors as well, despite the increased levels of hemin in vivo in these patients. The effect of hemin on relative gamma globin synthesis is inconsistent, however. In a few cases, delayed addition of hemin led to increased gamma globin synthesis. In time course studies of cultures from normal donors, hemin added on day 0 shifted the day of peak colony number from 13-14 to 16-20 days. The temporal decline in gamma globin synthesis was not altered. In cultures from sickle donors we found that the time for maximal colony number was later than in normals, occurring at 16-20 days even without hemin, and was not further delayed by hemin. The relative proportion of gamma globin synthesis was higher on day 14 in the sickle than the normal cultures, and the temporal decline was somewhat slowed in the sickle cultures by hemin. The elevated gamma synthesis and the later time for peak colony growth in the sickle cultures suggest that the erythroid progenitors in the blood of the sickle patients are less mature than those from normal individuals. There are several possible explanations for the detection of increased numbers of colonies in cultures containing hemin. Hemin may delay the final maturation of erythroblasts within erythroid colonies, thus shifting the time of maximal growth. It may also increase the extent of final maturation, leading to more complete hemoglobinization of the erythroblasts within the colonies, and thus increasing the number of colonies that are eventually recognized as erythroid.(ABSTRACT TRUNCATED AT 250 WORDS)

Funduscopic alterations in SS and SC hemoglobinopathies. Study of a Brazilian population

Fundus changes in sickle cell disease are well studied and documented according to their clinical and angiographic aspects. Sickle cell retinopathy was studied in a Brazilian population of 63 patients (41 with SS hemoglobinopathy, and 22 with SC hemoglobinopathy). All ophthalmoscopic changes observed in our patients were more frequent in the SC group with the exception of atrophic retinal tears, found only in the SS group. Proliferative retinopathy including its complications was seen in 54.54% of the eyes of the SC group, and in only 14.64% of the eyes of the SS group. Decreased vision is consequently greater in the SC group. Despite the great frequency of funduscopic changes in both groups, only 1 patient suffered irreversible visual loss due to retinal detachment operated on without success.

Retinal changes in sickle cell/hereditary persistence of fetal haemoglobin syndrome

We describe for the first time retinal changes in sickle cell/hereditary persistence of fetal haemoglobin syndrome, which is a rare and benign disorder. The changes are qualitatively similar to retinal disease seen with sickle haemoglobin and sickle C haemoglobin, but are mild.

Macular and perimacular vascular remodelling sickling haemoglobinopathies

The posterior pole vasculature of 100 patients with different sickling haemoglobinopathies was studied prospectively over a period of three years. Various abnormalities of the posterior pole vasculature were seen in 29 per cent of the patients. Continuous remodelling of the macular and perimacular vasculature occurred. Visual acuity was variably affected and sometimes remained intact.

Migratory white-without-pressure retinal lesions

Nine patients had white-without-pressure retinal lesions. These lesions were seen in areas of vitreoretinal adhesions. The configuration and location of these lesions changed over variable periods of time. The cause of this pecular migration is unknown, but may be related to separation and re-creation of vitreoretinal adhesions. The migratory nature of white-without-pressure areas has not, to our knowledge, previously been reported in the literature.

Pathology of the glomerulus in sickle cell anemia with and without nephrotic syndrome

Glomeruli from 6 cases of sickle cell disease (SS) with the nephrotic syndrome (NS) were compared histologically and quantitatively with glomeruli from 9 cases of SS, 10 cases of sickle cell trait (SCT), 4 cases of other hemoglobinopathies, all without NS, and normal controls. Five of 6 patients with SS and NS had extensive reduplication of their glomerular basement membranes and mild mesangial proliferation. Similar but milder lesions occurred in SS without NS but not in SCT or controls. Incidental renal disease occurred in 1 patient with SS and NS. Nephrotic syndrome was probably secondary to effects of sickle cell disease. Glomeruli in SS were significantly larger (>70%) than in SCT and controls. Mean total glomerular area per unit area of cortex in SS with normal BUN significantly exceeded that of SCT, which, in turn, was significantly greater than that of controls. Mechanisms for the histologic lesions and hypertrophy of the glomeruli were suggested.

Liver in haemoglobin H disease

There have been no published reports on the liver of patients with haemoglobin H disease. In 11 Chinese patients studied (six male and five female) with haemoglobin H disease hepatic function and histology were studied. Liver function was normal in all cases; however, the gamma globulin level was raised in four cases, the increase being mainly in IgG in all cases and IgA in six cases. Liver histology showed that one case had portal cirrhosis, six cases mild fibrosis, and four cases no fibrosis. Haemosiderosis, mainly in the parenchymal cells of the peripheral lobules, was mild in one case, moderate in four, and severe in the remainder of the cases.

Hemoglobin Philly (beta 35 tyrosine phenylalanine): studies in the molecular pathology of hemoglobin

An abnormal unstable hemoglobin, hemoglobin Philly, was found in three members of a family, each of whom had evidence of a chronic hemolytic state. The presence of the mutant protein was suggested by the rapid appearance of inclusion bodies upon incubation of erythrocytes with brilliant cresyl blue and by the increased heat precipitability of the hemoglobin. However, no abnormal hemoglobin could be demonstrated by electrophoresis or column chromatography. Sulfhydryl titration of the hemolysates with p-mercuribenzoate indicated that there was an average of four reactive sulfhydryl groups per hemoglobin molecule instead of the usual two. The total number of hemoglobin sulfhydryl groups was normal; six groups were measured when denatured globin was reacted with 5,5'-dithiobis[2-nitrobenzoic acid]. This indicated that the increased sulfhydryl reactivity was due to an increased availability to p-mercuribenzoate of the usually unreactive hemoglobin cysteines at beta112 and alpha104. After treatment for (1/2) hr with 4-5 moles of p-mercuribenzoate per mole of hemoglobin, electrophoresis revealed that 30-35% of the hemoglobin had been dissociated into alpha- and beta-chains. Normal hemolysates revealed negligible splitting after 72 hr of similar treatment. The alpha- and beta-chains of hemoglobin Philly were separated from the unsplit hemoglobin A by carboxymethyl cellulose chromatography. Fingerprint and amino acid analyses revealed that tyrosine beta35 was replaced by phenylalanine. In hemoglobin Philly there is loss of the normal hydrogen bond between the tyrosine hydroxyl group and the carboxyl group of aspartic acid alpha126 at the alpha(1)beta(1) contact. This shifts the equilibrium from hemoglobin tetramers toward monomers, exposing the beta112 and alpha104 cysteines. In the cell, precipitation of the unstable monomers may contribute to erythrocyte destruction.