Gene expression analysis revealed downregulation of complement receptor 1 in clonal B cells in cold agglutinin disease

Cold agglutinin disease (CAD) is a rare B-cell lymphoproliferative disorder of the bone marrow, manifested by autoimmune hemolytic anemia caused by binding of monoclonal IgM autoantibodies to the I antigen. Underlying genetic changes have previously been reported, but their impact on gene expression profile has been unknown. Here, we define differentially expressed genes in CAD B cells. To unravel downstream alteration in cellular pathways, gene expression by RNA sequencing was undertaken. Clonal B-cell samples from 12 CAD patients and IgM-expressing memory B cells from 4 healthy individuals were analyzed. Differential expression analysis and filtering resulted in 93 genes with significant differential expression. Top upregulated genes included SLC4A1, SPTA1, YBX3, TESC, HBD, AHSP, TRAF1, HBA2, RHAG, CA1, SPTB, IL10, UBASH3B, ALAS2, HBA1, CRYM, RGCC, KANK2, and IGHV4-34. They were upregulated at least 8-fold, while complement receptor 1 (CR1/CD35) was downregulated 11-fold in clonal CAD B cells compared to control B cells. Flow cytometry analyses further confirmed reduced CR1 (CD35) protein expression by clonal CAD IgM+ B cells compared to IgM+ memory B cells in controls. CR1 (CD35) is an important negative regulator of B-cell activation and differentiation. Therefore, reduced CR1 (CD35) expression may increase activation, proliferation, and antibody production in CAD-associated clonal B cells.

Cold Agglutinin-Mediated Autoimmune Hemolytic Anemia in Association with Antiphospholipid Syndrome

Antiphospholipid syndrome and cold agglutinin-mediated autoimmune hemolytic anemia are 2 distinct immune-mediated hematologic disorders. While no clear association exists between these 2 entities, complement activation is known to occur in both of them. Herein, we report a unique case of cold agglutinin hemolytic anemia in a patient with a known primary antiphospholipid syndrome.

Reticulocyte Hemoglobin Equivalent in Patients with Idiopathic Warm Autoimmune Hemolytic Anemia: Implication in the Development of Macrocytosis

OBJECTIVE

Patients with warm autoimmune hemolytic anemia (WAIHA) present with anemia that is highly heterogeneous, and often have macrocytic anemia with inappropriately elevated mean corpuscular volume (MCV). The goal of this retrospectivecase study is to elucidate the characteristics of anemia in patients with idiopathic WAIHA.

PROCEDURES

The hematological parameters were analyzed by automated hematology analyzers in 19 consecutive patients with idiopathic WAIHA. Thecontent of hemoglobin (Hb) in the reticulocytes was assessed as reticulocyte Hb equivalent (RET-He). Relevant laboratory data and medical records were retrospectively studied.

RESULTS

The median MCV was 102.7 fL and ten patients had macrocytic anemia with MCV above 100 fL. There was a significant correlation between the percentage of reticulocytes and MCV. The median RET-He value was 35.9 pg, and the reticulocytes of patients with higher MCV had higher RET-He. There was a significant correlation between red cell volume distribution width (RDW) andMCV, while the association between RDW and RET-He was not significant. Red blood cell agglutination was not seen in any of the patients. Relative folate deficiency was implied to contribute to the increased Hb content in the reticulocytes of WAIHA patients.

CONCLUSION

Reticulocytes in WAIHA patients often contain more Hb than normal reticulocytes and become inappropriately large, possibly due to relative folate deficiency. Elevated MCV in WAIHA patients is due to the increase in both the number and the Hb content of reticulocytes.

Cold agglutinin disease: where do we stand, and where are we going?

Primary cold agglutinin disease (CAD) is characterized by a very indolent bone marrow clonal B-cell lymphoproliferative disorder that initiates an autoimmune hemolytic anemia. The clonal B cells produce a monoclonal autoantibody termed cold agglutinin, most often of the immunoglobulin (Ig) Mκ class. After binding to its antigen, the IgM initiates a complement classical pathway-driven erythrocyte destruction, predominantly mediated by opsonization with complement protein C3b and extravascular hemolysis in the liver. We review the molecular biology, histopathology, clinical features, and diagnostic procedures in CAD. Some patients are only slightly anemic and do not require treatment, but moderate or severe anemia frequently occurs, and the disease burden has been underestimated. CAD should not be treated with corticosteroids. Several B-cell-directed treatment options are available, and complement-directed approaches are being rapidly developed. Current and possible future therapies are reviewed.

[Change and significance of Th17 cells and its secretive IL-17 in patients with autoimmune hemolytic anemia]

AIM

To observe the percentage of Th17 cells in the peripheral blood and levels of plasma IL-17 of patients with autoimmune hemolytic anemia (AIHA)before treatment and after glucocorticoid treatment and to explore their clinical significance.

METHODS

Flow cytometric assay were used to detect the rate of Th17 cells in AIHA patients. The level of plasma IL-17 in AIHA patients were measured by ELISA.

RESULTS

The rate of Th17 cells and the level of plasma IL-17 were significantly increased before treatment as compared with that in normal controls [(2.78 ± 0.59)%, (126.4 ± 11.6)ng/L vs (0.59 ± 0.15)%, (52.3 ± 4.8) ng/L](P < 0.01). After treatment, The percentage of Th17 cells (1.05±0.28)% was significantly decreased (P < 0.01). The same tendency was also found in the levels of plasma IL-17(78.5 ± 6.4) ng/L(P < 0.01).

CONCLUSION

The rate of Th17 cells and the lever of plasma IL-17 significantly elevate in AIHA patients. Glucocorticoid might play a role in AIHA treatment by down-regulating Th17 cells number and concentrations of IL-17.

Implication of oxidative stress as a cause of autoimmune hemolytic anemia in NZB mice

We have recently shown that deficiency of the superoxide dismutase 1 gene (SOD1) causes anemia and autoimmune responses against red blood cells (RBCs) and that transgenic expression of human SOD1 in erythroid cells rescues them. Because these phenotypes observed in SOD1-deficient mice are similar to autoimmune hemolytic anemia (AIHA), a causal connection between reactive oxygen species (ROS) and AIHA was examined using an AIHA-prone New Zealand Black (NZB) mouse. ROS levels in RBCs were high in young NZB mice, compared to control New Zealand White (NZW) mice, and increased during aging. Methemoglobin and lipid peroxidation products were elevated during aging, consistent with the elevated oxidative stress in RBCs of NZB mice. Severity of anemia and levels of intracellular ROS were positively correlated. Levels of antibodies against 4-hydroxynonenal and acrolein were also elevated in NZB mice. Transgenic expression of human SOD1 protein in RBCs of NZB mice suppressed ROS in RBCs and decreased the death rate. When RBCs from C57BL/6 mice were injected weekly into the same strain of mice, production of anti-RBC antibody was observed only in mice that had been injected with oxidized RBCs. Thus, oxidation-mediated autoantibody production may be a more general mechanism for AIHA and related autoimmune diseases.

[Selected problems concerning anaemia in systemic lupus erythematosus patients]

Haematological abnormalities are common in systemic lupus erythematosus (SLE) and may be manifested by anaemia of different pathogenesis. The objective of this article was to describe some data concerning autoimmune haemolytic anaemia, aplastic and megaloblastic ones accompanying SLE and also to present erythropoietin (EPO) function in the above mentioned diseases. In SLE many factors are produced which disturb the organism haematological balance both on the peripheral level and in the bone marrow. It is assumed that the autoantibodies produced in SLE are the main cause of anaemia. However it should be considered that quantitative changes in the number of erythrocytes observed in this disease are also caused by chronic inflammatory condition, which as the element of autoimmune disease impairs the endocrine function of the kidneys in EPO production. It influences bone marrow, iron metabolism and then haemopoiesis. Apart from humoral factors the role of mechanisms connected with immune cellular response is also considered.

Isolated microcytic anemia disclosing a unicentric Castleman disease: The interleukin-6/hepcidin pathway?

Castleman disease (CD) is a rare lymphoproliferative disorder of uncertain origin. Anemia is commonly reported and is related to an inflammatory mechanism. Occasionally an autoimmune hemolytic anemia appears as the leading clinical feature. Three histological types have been differentiated, a hyaline-vascular type (HV), a plasma cell type (PC), and a mixed type. Clinically CD is separated into unicentric (localized) or multicentric (generalized) forms. The former is most frequently of HV type (80-90%), affecting a single lymph node. The PC type is encountered in 10-20% of the unicentric CD and in almost all of the multicentric cases. Numerous systemic manifestations have been described usually associated with PC type. An isolated and markedly microcytic anemia revealing a unicentric CD has never been reported in English literature. Recent data concerning iron metabolism, interleukin-6 and hepcidin provide interesting clues to understand the particular microcytic anemia of CD.

Cold agglutinin induced autoimmune hemolytic anemia and NK-cell leukemia: a new association

Cold agglutinin induced autoimmune hemolytic anemia is uncommonly associated with leukemia and lymphomas. We present a case of a young Mexican female presenting with a cold agglutinin hemolytic anemia with expression of a rare Pr antigen specificity and an aggressive NK-cell leukemia. Our patient had a rapid fatal course. To our knowledge this is the first reported case of such an association.

Evaluation of liposomal clodronate in experimental spontaneous autoimmune hemolytic anemia in dogs

OBJECTIVES

Liposomal clodronate (dichloromethylene diphosphonate) has been used to deplete macrophages and block clearance of opsonized cells in mouse models of autoimmune disease. However, liposomal clodronate (LC) has not been previously evaluated in a large-animal spontaneous autoimmune disease model. Therefore, the safety and efficacy of LC treatment was assessed in normal dogs and in dogs with spontaneous autoimmune hemolytic anemia (AIHA).

METHODS

LC was administered intravenously first to healthy dogs and then to dogs with spontaneous, severe AIHA to determine if the treatment was safe and could block clearance of opsonized red blood cells (RBCs) in vivo. Studies were also conducted to assess the in vitro effects of LC on dog macrophages and dendritic cells.

RESULTS

Intravenous infusion of low doses of LC was well tolerated and blocked clearance of opsonized RBCs in normal dogs in vivo. LC was taken up by splenic macrophages and dendritic cells in vivo, and induced killing of macrophages and dendritic cells in vitro. Seven dogs with severe, spontaneous AIHA were treated with LC in a pilot study. Treatment was well tolerated, 2 of 7 LC-treated dogs with AIHA had a decrease in RBC clearance, and LC-treated dogs had significantly increased survival times compared to historical control dogs matched for disease severity.

CONCLUSIONS

These results indicate that LC can be safely administered intravenously to dogs and that even relatively low doses are capable of blocking RBC clearance and improving outcomes in a spontaneous large-animal model of AIHA. Therefore, additional studies of LC for treatment of autoantibody-mediated cytopenias in dogs and humans may be warranted.

Role of CD47 in erythroid cells and in autoimmunity

The cell surface glycoprotein CD47 (Integrin-associated protein/IAP) was originally identified as a regulator of integrin-dependent responses to extracellular matrix proteins. However, CD47 is ubiquitously expressed, also by cells that do not express integrins. Thus, during the last few years, it has been shown that CD47 has several important functions besides assisting integrin activation. This review will focus on the role of CD47 in erythrocytes. In these cells, CD47 was found to be an important link in the interaction between the band 3 complex and the Rh complex in the maintenance of erythrocyte membrane integrity. CD47 can also function as a marker of self on erythrocytes, and likely also on other cells, by binding to the inhibitory receptor SIRPalpha. In this way, SIRPalpha-expressing cells, like macrophages and dendritic cells, are less likely to phagocytose an autoimmune sensitized cell with CD47 on its surface than a CD47-deficient cell where this inhibitory mechanism will not be engaged. The interaction between CD47 and SIRPalpha seems to be important to limit destruction of host cells in autoimmune diseases like autoimmune hemolytic anemia (AIHA), where macrophages destroy antibody or complement opsonized cells.

Targeted disruption of Nrf2 causes regenerative immune-mediated hemolytic anemia

A basic leucine zipper transcription factor, NF-E2-related factor 2 (Nrf2), plays a critical role in the cellular defense mechanism by mediating a coordinate up-regulation of antioxidant responsive element-driven detoxification and antioxidant genes. Here, we report that targeted disruption of Nrf2 causes regenerative immune-mediated hemolytic anemia due to increased sequestration of damaged erythrocytes. Splenomegaly and spleen toxicity in Nrf2(-/-) mice raised a possibility of hemolytic anemia and splenic extramedullary hematopoiesis in Nrf2(-/-) mice. In support of this, hematology analysis revealed that Nrf2(-/-) mice suffer from anemia with abnormal red cell morphologies (i.e., Howell-Jolly bodies, acantocytes, and schistocytes). In addition, Nrf2(-/-) erythrocytes were more sensitive to H(2)O(2)-induced hemolysis, and erythrocyte-bound IgG levels were markedly increased in Nrf2(-/-) mice compared with Nrf2(+/+) mice. Because IgG bound to erythrocytes in the presence of oxidative damage in erythrocytes (regardless of Nrf2 genotype), these data support that Nrf2(-/-) erythrocytes have higher levels of damage compared with Nrf2(+/+) cells. Finally, Nrf2(-/-) mice showed increased levels of erythrocyte-bound IgG compared with Nrf2(+/+) mice after H(2)O(2) injection in vivo, suggesting that the decreased glutathione and increased H(2)O(2) render the Nrf2(-/-) mice more susceptible to toxicity. Taken together, these observations indicate that a chronic increase in oxidative stress due to decreased antioxidant capacity sensitizes erythrocytes and causes hemolytic anemia in Nrf2(-/-) mice, suggesting a pivotal role of Nrf2-antioxidant responsive element pathway in the cellular antioxidant defense system.

Levofloxacin-induced autoimmune hemolytic anemia

OBJECTIVE

To report a case of autoimmune hemolytic anemia (AIHA) secondary to levofloxacin.

CASE SUMMARY

An 82-year-old white man was treated with levofloxacin 500 mg/d for cellulitis. Three days following completion of levofloxacin therapy, the patient presented to the emergency department with severe jaundice, dizziness, and loss of vision. He received packed red blood cells (PRBCs) and was discharged home. Two days later at the follow-up visit, he was diagnosed with AIHA secondary to levofloxacin. The patient was hospitalized and treated with a tapering dose of prednisone and additional PRBC infusion. He was discharged from the hospital in stable condition after 3 days. Repeated hematologic laboratory studies following discharge demonstrated that the hemolytic anemia had resolved.

DISCUSSION

Hemolytic anemia due to levofloxacin is an extremely rare, but potentially fatal, adverse drug event. An objective causality assessment revealed that the adverse reaction was probable. To our knowledge, this is the first published case of levofloxacin-induced AIHA. However, there are published case reports of hemolytic anemia with other fluoroquinolones including ciprofloxacin (n = 12) and temafloxacin (n = 95). Temafloxacin was withdrawn from the market in 1992 due to this adverse effect. The mechanism by which levofloxacin triggers hemolytic anemia is unknown. We believe that an immune-mediated reaction is most likely.

CONCLUSIONS

Levofloxacin-induced AIHA is a rare but serious complication of therapy. Immediate discontinuation of the offending medication and treatment of the hemolytic anemia are essential. Until more information is available, levofloxacin should not be prescribed for patients with previous reactions to any fluoroquinolone.

Serial changes in the galactosylation of autoantibodies and serum IgG in autoimmune haemolytic anaemia

A number of systemic autoimmune diseases are associated with increased levels of the agalactosyl (G0) IgG isoforms that lack a terminal galactose from the C(H)2 domain oligosaccharide. The aims were to determine whether there are also persistently high levels of G0 autoantibodies or serum IgG in autoimmune haemolytic anaemia (AIHA), and whether any changes in galactosylation over time are related to the course of disease. Autoantibodies eluted from red blood cells, and serum IgG, were obtained from a patient with chronic AIHA over a 21 month period, and the degree of galactosylation measured using a lectin-binding assay. There were wide fluctuations in the galactosylation of autoantibody and serum IgG, but these changes were unrelated to the severity of the anaemia. The galactosylation of autoantibody and serum IgG varied independently, and the autoantibodies were preferentially G0 in comparison with serum IgG in only half of the serial samples. We conclude that AIHA differs from other, systemic autoimmune conditions in that high levels of G0 autoantibodies or serum IgG are not persistent, and that changes in galactosylation do not parallel the course of disease.

Characterization of the pathogenic KU-SHIV model of acquired immunodeficiency syndrome in macaques

By animal-to-animal passage in macaques we derived a pathogenic chimeric simian-human immunodeficiency virus (SHIV) that caused CD4+ T cell loss and AIDS in pigtail macaques and used it to inoculate 20 rhesus and pigtail macaques by the intravaginal and intravenous routes. On the basis of the outcome of infection and patterns of CD4+ T cell loss and viral load, disease was classified into four patterns: acute, subacute, chronic, and nonprogressive infection. During the study period, 15 of the 20 animals developed fatal disease, including AIDS, encephalitis, pneumonia, and severe anemia. Opportunistic pathogens identified in these animals included Pneumocystis, cytomegalovirus, Cryptosporidium, Toxoplasma, and Candida. No single parameter by itself predicted outcome, although a combination of low CD4+ T cell counts in blood, high plasma virus levels, and presence of autoantibodies to red blood cells reliably predicted a fatal outcome. Five animals (25%) died within 3 months of inoculation and constituted the group with acute disease, whereas the nine animals (45%) with subacute disease died between 3 and 8 months postinoculation. This 70% mortality within 8 months is significantly shorter than in HIV-1-infected human beings, of whom 70% develop fatal disease a decade after infection. SHIV infection in macaques provides a useful model with which to evaluate antiviral strategies, combining all the advantages of the SIVmac system, yet using a virus bearing the envelope gene of HIV-1.

Lymphocyte activation and cytokine production in autoimmune hemolytic anaemia (AIHA)

We studied 16 patients affected by autoimmune hemolytic anaemia (AIHA), both idiopathic and associated with other diseases (B and T lymphoma, B hepatitis, gastric carcinoma, systemic lupus erythematosus) or alpha-methyldopa therapy, in order to value T- and B-cell activation. We determined the count of T- and B-cell subsets in peripheral blood, the proliferative response of peripheral blood lymphocytes (PBL) to phytohemagglutinin (PHA) and to pokeweed mitogen (PWM), the percentage of CD25+ cells in culture and interleukin (IL)-1alpha, IL-2, IL-4, tumor necrosis factor (TNF)alpha and soluble IL-2 receptor (sIL-2R) levels in sera and in culture. Except for an increase in CD4+ and CD8+ T cell number in a case of AIHA associated with a T lymphoma and an increase in the percentage of CD5+ and PCA1+ B cells in two cases of AIHA associated with B lymphoma and with SLE, no further data showed a relationship with the disease possibly associated with AIHA, so both idiopathic and secondary AIHA cases were analyzed together. CD4+ T cells were reduced in number in 9 cases, while CD8+ T cells were reduced in 6 cases. The percentage of CD5+ B cells was increased in 5 cases. The percentage of PCA1+ cells was increased in all cases (mean +/- sd: 18 +/- 22 vs 0,2 +/- 1 in controls). The average PBL proliferative response to PHA was reduced (S.I. 71 +/- 55 vs 138 +/- 45 in controls) as well as that to PWM (S.I. 27 +/- 21 vs 75 +/- 24 in controls), despite IL-2 high levels, in all cases, in both sera (mean +/- sd: 648 +/- 351 pg/ml vs 16 +/- 4 pg/ml in controls) and culture supernatants (mean +/- sd: 1045 +/- 677 pg/ml vs 195 +/- 51 pg/ml in controls). In PHA stimulated cultures the percentage of CD25+ cells was reduced (mean +/- sd: 37 +/- 18 vs 63 +/- 14 in controls), sIL-2R levels were like controls in 7 cases. In sera sIL-2R levels were increased in all cases (mean +/- sd: 1256 +/- 465 U/ml vs 256 +/- 114 U/ml in controls), IL-1alpha was increased in all cases too, while IL-4 levels were increased only in 7 cases. Linear regression analysis generally showed a low relationship between S.I. and IL-2, IL-4 and sIL-2R levels in supernatants of PHA stimulated culture as well as between S.I. and the percentage of CD25+ cells. Taken together these data suggest a state of B- and T-cell hyperactivation in AIHA. The low PBL proliferative response in vitro, explained in previous studies as a temporary functional exhaustion, might be itself a sign of the complete lymphocyte activation occurring in vivo in AIHA.

Quantitation of erythrocyte-bound IgG subclass autoantibodies in murine autoimmune haemolytic anaemia

A quantitative and sensitive cellular enzyme-linked immunosorbent assay was developed for determining the number of molecules of IgG of each subclass bound to the surface of murine red blood cells (RBC). To develop standard titration curves, RBC from normal mice were treated with tannic acid and coated with a known concentration of purified myeloma of each IgG subclass. The quantity of each subclass bound to the surface of erythrocytes was determined by calculating the protein concentration of the bound IgG, which was then converted into number of molecules of IgG/RBC. The assay was used to quantify the number of autoantibodies of all four IgG subclass bound to the erythrocytes of mice injected with rat RBC. Twenty one days after the first immunisation, a mean number of 84,000 molecules of IgG1/RBC were detected, which increased to 114,500 molecules/RBC on day 28. On days 56 and 96 the mean concentration of IgG1 remained high, however by day 110 the mean level of IgG1 had decreased slighty to 69,500 molecules/RBC. By contrast, the mean concentration of IgG2a autoantibodies was considerably lower throughout the experiment, starting at 40,200 molecules/RBC on day 21 and dropping to 2,500 molecules/RBC by day 110. The mean quantities of IgG2b and IgG3 autoantibodies were similar to each other, and intermediate between the levels of IgG1 and IgG2a autoantibodies.

Pemphigus vulgaris associated with autoimmune hemolytic anemia and elevated TNF alpha

A 76-year-old female was admitted with many bullae and erythema on her trunk and extremities. A biopsy specimen showed significant intercellular edema in the lower epidermis and eosinophilic infiltration into the dermis and the epidermis. Immunofluorescent staining revealed the deposition of IgG in the intercellular area of her prickle cells. From these histologic findings and the typical clinical features, we diagnosed her as having pemphigus vulgaris. Examination of her blood revealed that she also suffered from autoimmune hemolytic anemia. Despite intensive treatment with prednisolone, she finally died. This case is of interest because of its rarity and the TNF alpha detected significantly in the blister fluid of this patient.

Demonstration of the deposition of hemosiderin in the kidneys of patients with paroxysmal nocturnal hemoglobinuria by magnetic resonance imaging

Hemosiderinuria caused by intravascular hemolysis is a characteristic clinical feature of an acquired hemolytic disorder, paroxysmal nocturnal hemoglobinuria (PNH). We examined the deposition of hemosiderin (iron) in the kidneys of 6 patients with PNH using magnetic resonance imaging (MRI). Three patients with autoimmune hemolytic anemia (AIHA), a hemolytic disorder showing extravascular hemolysis, served as controls. In five of the six patients with PNH, a characteristic T2-weighted MRI of the kidneys, suggesting the deposition of iron (hemosiderin) predominantly in the renal cortex, was obtained. Hemosiderin-deposition was not revealed in the kidneys of any of the patients with AIHA. We conclude that MRI is a sensitive means of detecting hemosiderin deposited in the renal cortex of patients with PNH and that this feature is considerably specific for diseases showing intravascular hemolysis, as represented by PNH.

Severe autoimmune hemolytic anemia with cold agglutinin and sclerodermic features--favorable response to danazol

A rare case of severe primary autoimmune hemolytic anemia with cold agglutinin and extensive cutaneous sclerodermic changes is reported. This association has not been previously documented in the literature. The anemia was refractory to steroids but responded to danazol treatment. Danazol may be an effective therapy in some cases of autoimmune hemolytic anemia with cold agglutinin.

Changes in protoporphyrin distribution dynamics during liver failure and recovery in a patient with protoporphyria and Epstein-Barr viral hepatitis

Acute liver failure with cholestasis, histologic and serologic evidence of Epstein-Barr viral infection, and associated autoimmune hemolytic anemia occurred in a patient with lifelong protoporphyria. Changes in previously established baseline protoporphyrin distribution dynamics in erythrocyte, plasma, and fecal excretion compartments were observed during the period of severe hepatic dysfunction and recovery. These changes were consistent with predictions of a previously described conceptual model for human protoporphyria.

Effect of estradiol and steroid analogues on the clearance of immunoglobulin G-coated erythrocytes

Although the disproportionate frequency of several immunologic disorders among women is well recognized, the effect of sex steroids on immunologic processes is unclear. We used an animal model, which has helped to elucidate the effect of corticosteroids in vivo, to quantitatively assess the effect of estradiol and steroid analogues on the immune clearance of IgG-coated erythrocytes. While corticosteroids impaired the clearance of IgG-coated erythrocytes, estradiol, in doses comparable to those achieved during pregnancy, significantly enhanced the clearance. Estradiol, however, did not enhance the splenic clearance of heat-altered erythrocytes. Splenic macrophages isolated from estradiol-treated animals expressed enhanced receptor affinity for the Fc portion of immunoglobulin G [Fc(IgG)], an effect probably responsible for the enhanced in vivo clearance. No consistent effect of estradiol on the splenic macrophage C3 receptors was observed. The synthetic androgen danazol, the mineralocorticoid deoxycorticosterone, and the cortisol metabolite tetrahydrocortisone did not alter the clearance of IgG-coated cells after 7 d of therapy. The estrogen antagonist/agonist tamoxifen enhanced the clearance of IgG-coated cells, but to a lesser extent than estradiol. An effect of estrogens on macrophage Fc (IgG) receptor-mediated clearance may explain in part the variation in clinical expression of several autoimmune disorders during changes in hormonal state, such as pregnancy.

Bone marrow hemosiderin does not always reflect body iron stores

Absence of hemosiderin from the bone marrow is sometimes encountered in patients who are not iron deficient. Two cases of autoimmune hemolytic anemia are described in which there was little or no hemosiderin in the marrow but large amounts in the spleen, which had been the major site of accelerated RBC destruction.

Quantitative assessment of erythropoiesis in haemolytic disease

Erythrokinetic parameters were estimated in 21 patients suffering from haemolytic disease using a mathematical model of iron kinetics. A proper definition of radioiron reflux from red cells to the plasma proved to be essential for an accurate estimate of effective and ineffective erythropoiesis in severe haemolytic conditions. Erythropoietic activity was increased in all the patients, with the marrow capable of sustaining erythropoiesis at about 6 times normal in hereditary spherocytosis and 3 times normal in autoimmune haemolytic anaemia. This proliferative effort was countered by an increase in ineffective erythropoiesis which was especially marked in hereditary spherocytosis.

Cellular immune deficiency with autoimmune hemolytic anemia in purine nucleoside phosphorylase deficiency

Immunologic and metabolic abnormalities were studied in a five year old boy with 0.07 per cent of normal erythrocyte purine nucleoside phosphorylase activity. The clinical course is characterized by severe autoimmune hemolytic anemia, a transient neurologic disorder with tremor and ataxia, and minor infectious illnesses. There is severe lymphopenia with decreased absolute numbers of T and B lymphocytes. Mitogen-stimulated blastogenesis is reduced, but response to allogeneic lymphocytes is normal. A monoclonal IgG protein is present. There is hypouricemia, elevated plasma inosine level, hypouricosuria and an increase in the urinary concentration of inosine and guanosine. The pattern of heterozygote distribution in the patient's family is compatible with an autosomal recessive trait in which heterozygotes are identifiable. In addition, the unusual laboratory and clinical manifestations of this patient illustrate the heterogeneity of the clinical syndrome associated with purine nucleoside phosphorylase deficiency.

Depletion of cardiac norepinephrine during two forms of hemolytic anemia in the rat

Knowledge of the status of cardiac norepinephrine (NE) during anemia could lead to a better understanding of the role the sympathetic nervous system plays in cardiac function during anemia. Rats were made anemic by treatment with phenylhydrazine (PHZ). After the rapid onset of anemia, 60% of the stored NE in the heart was lost within 48 hours after treatment. Associated with the loss of cardiac NE was an increase in the wet weight of the heart, which reached a value 40% above control 48 hours after treatment. PHZ itself probably does not directly mediate this depletion of NE, since the vas deferens, brain and spleen had a normal store of NE at 48 hours. This contention was supported when rats, treated with PHZ, were transfused with normal rat red blood cells. This transfusion resulted in PHZ-treated rats which were not anemic. The hearts of these rats were not depleted of NE, but the hearts of the nontransfused, PHZ-treated controls were. Anemia also was induced by treating rats with anti-rat red blood cell serum. The hearts of these rats also were depleted of NE. These experiments show that during two forms of anemia there is a loss of NE from the sympathetic neurons innervating the heart. The effect of this on regulation of cardiac function remains to be determined.

Autoimmune haemolytic anaemia induced in mice immunized with rat erythrocytes

C₃H mice immunized with rat erythrocytes developed autoimmune haemolytic anaemia which was very similar to the `warm-type' autoimmune haemolytic anaemia of man. There was evidence of anaemia, reticulocytosis, shortened survival times of ⁵¹Cr-labelled erythrocytes in vivo, and a high incidence of positive direct Coombs' tests. There was no evidence of spherocytosis or of increased susceptibility to osmotically induced lysis. Bone marrow smears showed evidence of erythroid hyperplasia. Splenectomized mice were more severely affected than unsplenectomized mice. In these mice anaemia was more severe, individual positive direct Coombs' tests were stronger; ⁵¹Cr-labelled erythrocytes were cleared faster and the compensatory erythroid hyperplasia was less marked. After immunization was stopped both groups of mice quickly became haematologically normal. However, in mice in which immunization was continued, the blood pictures eventually reverted towards normal except for the persistent positive direct Coombs' tests. C57/B1 mice were also susceptible to the disease process but to a much lesser degree than C₃H mice.

Cell-free hemoglobin synthesis in beta-thalassemia

Human ribosomes obtained from the reticulocytes of patients having either homozygous beta-thalassemia (thalassemia ribosomes) or a hematological disorder unrelated to thalassemia ("normal" ribosomes) have been utilized in a cell-free system highly active in the synthesis of intact human globin chains. This system is dependent on the addition of a ribosomal wash fraction from reticulocytes that contains factors necessary for chain initiation. In response to the ribosomal wash fraction, isolated from either thalassemia, normal human, or rabbit reticulocytes, normal human ribosomes synthesize equal amounts of alpha and beta chains. In contrast, in response to all three types of ribosomal wash fractions, thalassemia ribosomes synthesize 8-times more alpha than beta chains, a ratio similar to that produced in the intact cells of these patients. The molecular defect in beta-thalassemia, therefore, does not appear to be associated with initiation factors.