AB0 blood groups,inv serum groups,and serum proteins in leprosy patients from West Bengal (India)

Summary The associations between ABO blood groups and prevalence as well as type and severity of the leprosy infection were examined in 1034 Indians from West Bengal (leprosy patients and normal controls). There are no associations in the present series; combined analysis of 41 series from the literature (ours included) gives a slightly, but significantly higher frequency of groups A and AB as compared to B and 0 in leprosy patients. Groups A, B, and AB are also somewhat more frequent in lepromatous as compared with nonlepromatous leprosy.A lower level of ₂-globulins in the serum of leprosy patients of groups A and AB as compared with patients of groups B and 0, which had been described earlier in 683 leprosy patients from Thailand, was confirmed in the present series.In the Thai series of patients, a significant association between the AB0 blood groups and the Inv serum groups was observed: Persons having blood group A and AB as well as the Inv (1) type were significantly more frequent than expected. This association, however, was not confirmed in the Indian material.

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Zusammenfassung Die Beziehungen zwischen AB0-Blutgruppen sowie Häufigkeit, Typ und Verlauf der Lepraerkrankung wurden an 1034 Indern aus West-Bengalen (Lepra-Patienten und normalen Kontrollen) untersucht. In dieser Serie fanden sich keine Beziehungen. Eine kombinierte Analyse von 41 Serien aus der Literatur (unsere eingeschlossen) gibt eine gering, aber signifikant erhöhte Häufigkeit der Gruppen A und AB im Vergleich zu B und 0 bei Lepra-Patienten. Die Gruppen A, B und AB sind im Gesamtmaterial ebenfalls etwas häufiger bei lepromatöser im Vergleich zu nichtlepromatöser Lepra.Bei 683 Lepra-Patienten aus Thailand hatten wir zuvor eine Verminderung der ₂-globuline bei Gruppen A und AB im Vergleich zu B und 0 beschrieben. Dieser Befund wurde an dem indischen Material bestätigt.Bei den thailändischen Patienten fanden sich auch Hinweise für eine Beziehung zwischen AB0- und Serum Inv-Gruppen: Personen, die sowohl A oder AB als auch den Typ Inv (1) aufwiesen, waren signifikant häufiger als erwartet. Dieser Befund konnte jedoch in dem indischen Material nicht bestätigt werden.

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This study was supported by the Deutsche Forschungsgemeinschaft.     

Zur Verbreitung der ABO-Blutgruppen in der Bevölkerung Nordthailands

2048 subjects in North Thailand were examined for AB0 blood groups. A control group representative of the population of the provinces of Chiengmai and Lampun was formed of 382 examinees and 3403 blood donors.The distribution of AB0 groups in this population is similar to that of Central Thailand. Some ethnic groups show significant deviations: The Miao tribe, originating in South China, has a much higher frequency of B. There was a significant reduction in gene A and B in the younger generation of this tribe. The Thai Yong, people who migrated to North Thailand from Yunnan in the 19th century, show an AB0 distribution similar to Chinese in Yunnan. They differ significantly from the Northern Thai. There is also a difference in the distribution of -thalassaemia and hemoglobin E between these two groups.Male leprosy patients showed an excess of group A which was not present in female patients. The percentage of severely ill patients was much higher in the males. Differentiation into lepromatous and tuberculid forms is not available. Among 108 people who had suffered from smallpox approximately 20 years ago there was an excess of groups 0 an B in comparison to the control group.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Inv phenotypes and quantitative gamma globulin determinations in leprosy patients and control populations from India and Thailand

Summary Two problems were examined: 1. Is there an association between prevalence and clinical course of leprosy and the Inv(1) polymorphism? 2. Do the Inv(1) types influence the amount of gamma globulin present in the serum?Material: 961 Indians (302 with lepromatous, 284 with nonlepromatous leprosy; 375 controls) from 5 different caste groups, districts of Bankura and Purulia, West Bengal; 494 leprosy patients from Thailand (240 with lepromatous, 254 with nonlepromatous leprosy); 988 controls; this control group was examined only for Inv type, not for gamma globulins.Results: 1. There seems to be no association between leprosy and Inv type. 2. No association between Inv type and gamma globulin content of the serum was found. 3. The phenotype frequencies in the Inv system are within the range known for other Indian and Asian populations.

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Zusammenfassung Zwei Probleme wurden untersucht: 1. Besteht eine Beziehung zwischen der Häufigkeit und dem klinischen Verlauf der Lepra und dem Inv(1)-Polymorphismus? 2. Beeinflussen die Inv(1)-Typen die Gammaglobulinmenge im Serum?Material: 961 Inder (302 mit lepromatöser, 284 mit nichtlepromatöser Lepra; 375 Kontrollen) aus 5 verschiedenen Kasten und aus den Distrikten Bankura und Purulia, West-Bengalen, 494 Leprapatienten aus Thailand (240 mit lepromatöser, 254 mit nichtlepromatöser Lepra); 988 Kontrollen. Diese Kontrollgruppe wurde nur auf dem Inv-Typ, nicht auf Gammaglobuline hin untersucht.Ergebnisse: 1. Es besteht offenbar keine Beziehung zwischen Lepra und Inv-Typ. 2. Es konnte keine Beziehung zwischen dem Inv-Typ und dem Gammaglobulingehalt des Serums aufgefunden werden. 3. Die Phänotyp-Häufigkeiten im Inv-System bewegen sich im Rahmen dessen, was für andere indische und asiatische Populationen bekannt ist.

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This study was supported by the Stiftung Volkswagenwerk and the Deutsche Forschungsgemeinschaft.     

Die Korrelation von Blutgruppenantigenen und-substanzen mit hypertonischer Erkrankung

We have investigated in 383 hypertonics, 151 males and 232 females, the AB0 blood groups, secretion of blood group substances AB0 (H), Rh₀ (D) factor, M and N groups and haptoglobin groups in the serum.Most patients were 40–50 years old and older, suffering from a fixed arterial hypertension with a diastolic blood pressure not lower than 110 mm Hg. All patients with renal, matabolic or nervous disorders were excluded from our series.In comparison with normal values in Czechoslovak population a significantly lower percentage was ascertained of nonsecretors of group substances in both sexes of B group hypertonics. In 72 persons of group B there were 8 nonsecretors i.e. 11.11% as compared with 37.84% nonsecretors in normal population; for 1 degree of freedom P < 0.001, for 4 degrees of freedom P < 0.05.Furthermore, in male hypertonics a preponderance of 0 over A, in female hypertonics that of A over 0 were ascertained. There were 39.07% male hypertonics of blood group 0 in comparison with 33.25% of group 0 in normal population and 28.88% in female hypertonics.In males hypertonics the blood group A appeared in 33.11%, the normal values being 40.79% and the incidence in females hypertonics being 45.26%.These differences achieved statistically significant values only in mutual comparison of the male and female group of hypertonics.In distribution of characters M/N and haptoglobin types no deviations from normal values were observed.

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Technische Mitarbeit: B. Knedlhansová und J. Benetková     

Weitere Untersuchungsergebnisse zur Frage der unterschiedlichen Verteilung der ABO-Blutgruppen bei erstgeborenen und nachgeborenen Kindern

Summary The ABO blood group distribution among 1284 first-born children is compared with the frequency of the blood groups among 2388 later-born children. Among the later-born children the blood group O is more frequent, whereas the blood groups B and AB are rarer. From the fifth child on both the increase of the blood group O and the decrease of the groups B and AB become more evident. The total frequency of boys is practically the same both in the different blood groups and in the sum of all first and later-born children. Within the blood group O, however, boys are predominating among the first-born children, but are less numerous among the later-born children. Within the blood group AB on the contrary there is a lack of boys among the first-born children and an excess of boys among the later-born children. The same distribution but to a smaller extent might be found within the blood group B among a not selected material. In the same way the change of the sexual distribution seems to rise with the increasing number of children, as it appears from the rate from the fifth child onward.

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(Ärztl. Leiter: Prim. Dr. W. Kircher)     

Spheroidal bodies and globi of human leprosy

From the plasma and/or buffy coats of 80% of 38 cases of (tuberculoid and lepromatous) leprosy have been isolated in pure culture a group of spheroidal organisms (spheroidal bodies of leprosy, SPBL) showing on various media a versatility of differention ranging from naked protoplasts to globi containing acid-fast rods. The acid-fastness of the latter, like the unique acid-fastness of leprosy bacilli from lepromatous leprosy, can be extracted with C₅H₅ N. Inoculation of chick embryos with SPBL elicits the nodular response evoked by homogenates of lepromatous tissue. From these nodules SPBL can be recovered in pure culture. SPBL appears to be the long sought etiologic agent of leprosy.     

Inhibition of apoptosis, activation of NKT cell and upregulation of CD40 and CD40L mediated by M. leprae antigen(s) combined with Murabutide and Trat peptide in leprosy patients

Protective immunity against intracellular pathogen Mycobacterium leprae is dependent on the activation of T cells. Repeated stimulation of T cells by M. leprae antigens MLCwA (M. leprae total cell wall antigen) and ManLAM (mannose-capped lipoarabinomannan), may lead to apoptosis in leprosy patients. In the present study, inhibition of the Fas-induced apoptosis of peripheral blood mononuclear cells of leprosy patients was investigated using above M. leprae antigen(s), in combination with immunomodulators murabutide (MB) and a Trat peptide in particulate form (liposome). Incubation of the cells with antigen containing the two immunomodulators in particulate form (liposomes) led to decrease in percentage of propidium iodide positive cells and T cells expressing Fas–FasL as well as decreased caspase-8/-3 activities in lepromatous patients, thereby inhibiting apoptosis, while converse was true upon stimulation with soluble antigen. Concurrently, there was an upregulation of antiapoptotic protein Bcl-x_L in lepromatous patients, leading to the inhibition of apoptosis. It was also observed that same formulation upregulated the expression of CD40 on B cells and monocytes-macrophages and CD40L on T cells of lepromatous leprosy patients. The same liposomal formulation significantly increased the expression of CD1b and CD1d on monocytes-macrophages as well as percentage of NKT cells secreting IFN-γ in lepromatous leprosy patients. Thus, the liposomal formulation of antigen with the immunomodulators in vitro promoted the activation of CD40:CD40L pathways and NKT cell function involved in providing cell-mediated immunity to these patients. The same formulation also caused reversal of T cell anergy by inhibiting apoptosis through decreased expression of death receptors (Fas–FasL) and caspase activities (3 and 8) and increased expression of antiapoptotic protein Bcl-x_L in these patients.     

AB0-Blutgruppen bei rheumatischem Fieber und rheumatischer Karditis

The authors desribe a highly significant association between the AB0 blood group system and rheumatic carditis in Budapest samples (770 patients, 3830 controls). Persons belonging to blood group AB or A are more susceptible to this disease than others, while groups B and 0 are relatively protected. The influence of AB0-locus on the disease can be estimated as being of the order of 1/2% by the relative risk x=1.376 and a 2% incidence. The evaluation of studies published so far proved only the relative protection of group 0 against rheumatic fever; it seems probable that of persons suffering from rheumatic fever especially those of group A are more susceptible to develop carditis. The hypothesis is discussed that the relative protection of the blood group 0 and of the secretor phenotype against rheumatic fever could be based on the partial identity of the determinant groups of the human H-antigen —which is found in abundance in the body fluids of all secretors-and of the C-substance of the group A Streptococcus, which inhibits the allergic reaction.

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Direktor: Dr. Gy. Bodrogi

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Direktor: Prof. Dr. M. Malán     

Increase in TGF-β Secreting CD4+CD25+ FOXP3+ T Regulatory Cells in Anergic Lepromatous Leprosy Patients

Background

Lepromatous leprosy caused by Mycobacterium leprae is associated with antigen specific T cell unresponsiveness/anergy whose underlying mechanisms are not fully defined. We investigated the role of CD25⁺FOXP3⁺ regulatory T cells in both skin lesions and M.leprae stimulated PBMC cultures of 28 each of freshly diagnosed patients with borderline tuberculoid (BT) and lepromatous leprosy (LL) as well as 7 healthy household contacts of leprosy patients and 4 normal skin samples.

Methodology/Principle Findings

Quantitative reverse transcribed PCR (qPCR), immuno-histochemistry/flowcytometry and ELISA were used respectively for gene expression, phenotype characterization and cytokine levels in PBMC culture supernatants. Both skin lesions as well as in vitro antigen stimulated PBMC showed increased percentage/mean fluorescence intensity of cells and higher gene expression for FOXP3⁺, TGF-β in lepromatous (p<0.01) as compared to tuberculoid leprosy patients. CD4⁺CD25⁺FOXP3⁺ T cells (Tregs) were increased in unstimulated basal cultures (p<0.0003) and showed further increase in in vitro antigen but not mitogen (phytohemaglutinin) stimulated PBMC (iTreg) in lepromatous as compared to tuberculoid leprosy patients (p<0.002). iTregs of lepromatous patients showed intracellular TGF-β which was further confirmed by increase in TGF-β in culture supernatants (p<0.003). Furthermore, TGF-β in iTreg cells was associated with phosphorylation of STAT5A. TGF-β was seen in CD25⁺ cells of the CD4⁺ but not that of CD8⁺ T cell lineage in leprosy patients. iTregs did not show intracellular IFN-γ or IL-17 in lepromatous leprosy patients.

Conclusions/Significance

Our results indicate that FOXP3⁺ iTregs with TGF-β may down regulate T cell responses leading to the antigen specific anergy associated with lepromatous leprosy.     

Impairment of alternate pathway (CD2) of T cell activation in leprosy

Recent studies in basic immunology have been directed towards the understanding of the mechanism of T cell activation. T cells can be activated to proliferatevia the classical pathway through the antigen receptor (CD3-Ti) orvia the alternate pathway through the CD2 receptor. Since immunologic unresponsiveness in lepromatous leprosy is considered to be due to the inability of T cells to proliferate upon stimulation, we have been interested in the nature of these receptors and the activation pathways in lymphocytes of leprosy patients. In the present investigation we demonstrate: (i) CD2 receptor (E-receptor) is downregulated in bacterial index positive lepromatous leprosy patients. (ii) The alternate pathway of T cell activation is impaired in lepromatous patients as revealed by the inability of their lymphocytes to proliferate in response to a pair of mitogenic anti-CD2 monoclonals. (iii) The addition of recombinant interleukin 2in vitro restores the ability of lymphocytes from lepromatous patients to proliferate in response to anti-CD2 antibodies. (iv) Interestingly, CD2 modulation and the associated functional impairment could be brought about in peripheral blood lymphocytes from normal subjects by prior treatment withMycobacterium leprae in vitro. This approach would be useful in understanding the molecular events leading to the defective T cell functions in leprosy.     

The HLA system and leprosy in Thailand

Summary To investigate immunogenetics of leprosy, 205 leprosy patients (26 with tuberculoid, 57 with borderline-tuberculoid, 21 with borderline, 31 with borderline-lepromatous, and 70 with lepromatous leprosy) have been typed for HLA antigens, and compared with 183 healthy controls from the same region (Nothern Thailand). There was no significant difference between the overal group of leprosy patients or the three borderline classes and the controls. The two polar forms, tuberculoid and lepromatous leprosy, however, showed significant associations: HLA-A2 is decreased and HLA-Bw17 is increased in tuberculoid leprosy; HLA-B7 is increased in lepromatous leprosy. When both polar forms are compared with each other, HLA-A2 is significantly higher, HLA-Bw40 lower in patients with lepromatous than in those with tuberculoid leprosy. The results are discussed with respect to the different immune responsiveness in the two polar forms of leprosy.     

Reciprocity between Regulatory T Cells and Th17 Cells: Relevance to Polarized Immunity in Leprosy

T cell defect is a common feature in lepromatous or borderline lepromatous leprosy (LL/BL) patients in contrast to tuberculoid or borderline tuberculoid type (TT/BT) patients. Tuberculoid leprosy is characterized by strong Th1-type cell response with localized lesions whereas lepromatous leprosy is hallmarked by its selective Mycobacterium leprae specific T cell anergy leading to disseminated and progressive disease. FoxP3+ Regulatory T cells (Treg) which are essential for maintaining peripheral tolerance, preventing autoimmune diseases and limiting chronic inflammatory diseases also dampen proinflammatory T cells that include T helper 17 (Th17) cells. This study is aimed at evaluating the role of Treg cells in influencing other effector T cells and its relationship with the cytokine polarized state in leprosy patients. Peripheral blood mononuclear cells from of BT/TT (n = 15) and BL/LL (n = 15) patients were stimulated with M. leprae antigen (WCL) in presence of golgi transport inhibitor monensin for FACS based intracellular cytokine estimation. The frequency of Treg cells showed >5-fold increase in BL/LL in comparison to BT/TT and healthy contacts. These cells produced suppressive cytokine, IL-10 in BL/LL as opposed to BT/TT (p = 0.0200) indicating their suppressive function. The frequency of Th17 cells (CD4, CD45RO, IL-17) was, however, higher in BT/TT. Significant negative correlation (r = -0.68, P = 0.03) was also found between IL-10 of Treg cells and IL-17+ T cells in BL/LL. Blocking IL-10/TGF-β restored the IL-17+ T cells in BL/LL patients. Simultaneously, presence of Th17 related cytokines (TGF-β, IL-6, IL-17 and IL-23) decreased the number of FoxP3+ Treg cells concomitantly increasing IL-17 producing CD4+ cells in lepromatous leprosy. Higher frequency of Programmed Death-1/PD-1+ Treg cells and its ligand, PDL-1 in antigen presenting cells (APCs) was found in BL/LL patients. Inhibition of this pathway led to rescue of IFN-γ and IL-17 producing T cells. Results indicate that Treg cells are largely responsible for the kind of immunosuppression observed in BL/LL patients. This study also proves that Treg cells are profoundly affected by the cytokine milieu and this property may be utilized for benefit of the host.     

Antibodies against BCG antigen 60 in mycobacterial infection.

A sensitive specific radioimmunoassay was developed to measure antibodies against BCG antigen 60, a prominent antigenic component of BCG bacilli which cross-reacts with similar components in many mycobacterial species including Mycobacterium leprae and M tuberculosis. A lepromatous serum pool had anti-BCG-60 activity with a titre of 10(5) and the tuberculoid pool a titre of 10(4). Testing of individual sera showed striking variations within groups of patients with lepromatous and tuberculoid leprosy. In five of the 20 tuberculoid leprosy sera the anti-BCG-60 activity was above the median for the lepromatous group. The current view that antibody formation against mycobacterial antigens is very low in tuberculoid leprosy thus no longer appears to be tenable. Sera from eight patients with active pulmonary tuberculosis also showed a striking variation in anti-BCG-60 content, and the median value of this group was even higher than in those with lepromatous leprosy.     

ABO blood groups,leprosy, and serum proteins

Summary In 683 leprosy patients from Chiang Mai, Thailand, the associations between ABO blood groups, type and clinical features of leprosy, and electrophoretically identifiable serumprotein fractions (albumins: ₁-, ₂-, - and -globulins) were examined. Besides, the blood group frequencies in 388 leprosy patients were compared with suitable controls. Blood groups A and AB turned out to be somewhat more frequent in patients than in controls. Combined analysis with 31 series from literature reports gave X=1.0776; ²=1)=12.232. In comparisons within our group of patients which contained almost exclusively lepromatous and dimorphous patients a certain tendency towards more severe involvement of blood group A was observed within the lepromatous group and a higher frequency of eye involvement in group A was (weakly) significant (²=1)=6.188).As to serum proteins ₁- and ₂-globulins were decreased (weakly) significantly in blood group A patients who were at least 40 years old. Furthermore, a number of relationships of serum protein fractions with age, sex, and state of the infection, most of which are known from the literature, could be confirmed.     

Surface membrane changes in lepromatous macrophages affecting the adherence ofMycobacterium leprae

Macrophages from lepromatous leprosy patients showed poor adherence toMycobacterium leprae. The phagocytic activity of the macrophages was not correlated to the influence on the adherence ability. Based on the phagocytic behaviour of macrophages from normal individuals and from lepromatous leprosy, patients as well as the action of neuraminidase in reversing the extent of adherence, it is suggested that macrophages from lepromatous leprosy patients differ from those from normal individuals in regard to their surface properties. There was no relationship between the degree of adherence and the concentration of Fc receptors of the macrophages. It was also shown that an extract of lysed macrophages from lepromatous leprosy patient was able to reduce the adherence ofMycobacterium leprae to normal macrophages. This study shows that adherence is a good indicator of the surface property of macrophages which in turn could play an important role in the cell mediated immunity of the patient. The observations suggest altered macrophage membrane structure in the long term-treated, otherwise normal, lepromatous leprosy patients.     

Suppressor T lymphocytes from lepromatous leprosy skin lesions

The immune response in leprosy forms a spectrum with lepromatous leprosy patients exhibiting specific unresponsiveness to antigens of Mycobacterium leprae. This unresponsiveness is thought to be related to the prevalence of T8-positive lymphocyte in these lepromatous lesions. To analyze the immunoregulatory function of these T8 cells, we developed simple procedures to extract lymphocytes from skin biopsy specimens of patients with leprosy. These lymphocytes were sorted for T8 and T4 positive cells, and cell lines were established by expansion with interleukin 2 (IL 2) and irradiated feeder cells. All T8 positive lines tested were positive for IL 2 receptors and HLA-DR determinants. These lines were additionally assayed for lepromin-induced suppression of the normal peripheral blood lymphocyte Con A proliferative response. Thirteen of 32 lines from six lepromatous patients showed significant suppressor activity, whereas nine lines from six tuberculoid patients and one line from normal peripheral blood failed to show suppression (p less than 0.001). Taken together, the finding of M. leprae-triggered suppressor cells within lepromatous skin lesions may in part explain the M. leprae unresponsiveness of lepromatous leprosy patients.     

Biochemical characterization of the feline AB blood group system

The biochemical nature of the feline AB blood group system was characterized by analysing red blood cells from homozygous (genotype A/A) and heterozygous (A/B) type A, type B (B/B), and type AB cats. High performance thin layer chromatography (HPTLC) of red cell gly-colipids revealed that specific neuraminic acids (NA) on gangliosides, containing ceramide dihexoside (CDH) as a backbone, correlated with the feline AB blood group antigens. Although disialogangliosides predominated, mono- and trisialogangliosides were also isolated. B cats expressed solely N-acetyl-NA (NeuNAc) on these gangliosides. In addition to expressing N-glycolyl-NA (NeuNGc) containing gangliosides, A red cells have gangliosides with only NeuNAc or mixtures of both NA. HPTLC profiles of disialogangliosides from homozygous and heterozygous A cats differed slightly in the quantity of disialogangliosides. Equal amounts of NeuNAc and NeuNGc containing disialogangliosides, as well as two intermediary forms, were recovered from AB erythrocytes. Analysing disialogangliosides from red cells belonging to 17 genetically related cats, we consistently obtained the expected disialoganglio-side profile, based on blood typing and pedigree information. SDS-PAGE of red cell membrane proteins and blotting with Triticum vulgaris, a lectin recognizing NeuNAc, revealed glycoproteins of approximately 51, 53, and 80 kD in B and AB cats but only a faint band of approximately 53 kD in A cats. By haemagglutination, Triticum vulgaris could also distinguish different blood types by specifically binding to B and AB cells. Flow cytometry showed that more anti-B bound to B cells than anti-A bound to A cells. Although AB cells had a broad range of fluorescence when compared to the profiles seen with A and B cells, the mean fluorescence with AB cells was half of that seen with A or B. These results further characterize the antigens determining the feline AB blood group system illustrating differences between A, B and AB cats, and between homozygous and heterozygous A cats.     

Mycobacterium leprae mediated stimulation of macrophages from leprosy patients and hydrogen peroxide production

Macrophages cultured from the peripheral blood of normal individuals, tuberculoid leprosy patients and long-term-treated, bacteriologically negative lepromatous leprosy patients are able to release hydrogen peroxide on stimulation withMycobacterium leprae. Macrophages from lepromatous leprosy patients who are bacteriologically positive produce considerably lower levels of hydrogen peroxide, even though stimulation of these cells withMycobacterium leprae is definitely demonstrable. This differential stimulation of macrophages appears to be largely specific toMycobacterium leprae. There is also a good indication that decreased stimulation of macrophages from positive patients could be due to an after-effect of infection. It is possible that while other factors aid survival ofMycobacterium leprae in the macrophages, hydrogen peroxide may not be as effective in the killing of the bacteria in infected patients as it would be, perhaps, in other infections.     

Purification and characterization of genetic variants of 6-phosphogluconate dehydrogenase

This paper describes the physicochemical characteristics in partially purified enzyme on subjects with the Pd A, Pd AB, and Pd B variants of 6-phosphogluconic dehydrogenase (6PGD). For these studies, whole blood was purified about 225-fold using ion exchange chromatography on DEAE cellulose column and fractionation with ammonium sulfate. 6PGD emerges as a single peak between 0.01 m and 0.1 m phosphate buffer on the column and is precipitated in the 55–80% fraction of ammonium sulfate. This purified enzyme can be stored frozen for several months without appreciable loss of activity and contains no detectable activity of glucose 6-phosphate dehydrogenase and glutathione reductase. The three variants of partially purified 6PGD varied from each other in two respects. The transitional temperature is 47.8 C for Pd A, 45.4 C for Pd AB, and 41.1 C for Pd B. The K _m for 6PGA is 30 m for Pd A, 21 m for Pd AB, and 15 mfor Pd B. These observations add further strength to the concept that the polymorphism in 6PGD represents alterations in either the configuration or structure of the protein molecule itself.Supported by grants from the Chicago Community Trust and the U.S. Public Health Service (Tl-AM-5186).