Biologic activity of cold-reacting autoantibodies (second of two parts)

I-branched carbohydrates as emerging effectors of malignant progression

Cell surface carbohydrates, termed "glycans," are ubiquitous posttranslational effectors that can tune cancer progression. Often aberrantly displayed or found at atypical levels on cancer cells, glycans can impact essentially all progressive steps, from malignant transformation to metastases formation. Glycans are structural entities that can directly bind promalignant glycan-binding proteins and help elicit optimal receptor-ligand activity of growth factor receptors, integrins, integrin ligands, lectins, and other type-1 transmembrane proteins. Because glycans play an integral role in a cancer cell's malignant activity and are frequently uniquely expressed, preclinical studies on the suitability of glycans as anticancer therapeutic targets and their promise as biomarkers of disease progression continue to intensify. While sialylation and fucosylation have predominated the focus of cancer-associated glycan modifications, the emergence of blood group I antigens (or I-branched glycans) as key cell surface moieties capable of modulating cancer virulence has reenergized investigations into the role of the glycome in malignant progression. I-branched glycans catalyzed principally by the I-branching enzyme GCNT2 are now indicated in several malignancies. In this Perspective, the putative role of GCNT2/I-branching in cancer progression is discussed, including exciting insights on how I-branches can potentially antagonize the cancer-promoting activity of β-galactose-binding galectins.

Waldenström's macroglobulinemia - a review

Waldenström's macroglobulinemia (WM) is a lymphoproliferative disease of B lymphocytes, characterized by a lymphoplasmocytic lymphoma in the bone marrow and by IgM monoclonal hypergammaglobulinemia. It was first described in 1944 by Jan Gösta Waldenström, reporting two patients with oronasal bleeding, lymphadenopathy, anemia, thrombocytopenia, high erythrocyte sedimentation rate and serum viscosity, normal radiography and bone marrow infiltrated by lymphoid cells. The WM is a rare disease with a typically indolent clinical course, affecting mainly individuals aged between 63 and 68 years. Most patients have clinical signs and symptoms related to hyperviscosity resulting from IgM monoclonal gammopathy, and/or cytopenias resulting from bone marrow infiltration by lymphoma. The differential diagnosis with other lymphomas is essential for the assessment of prognosis and therapeutic approach. Treatment of patients with asymptomatic WM does not improve the quality of life of patients, or increase their survival, being recommended, therefore, their follow-up. For the treatment of symptomatic patients, alkylating agents, purine analogs and anti-CD20 monoclonal antibodies are used. However, the disease is incurable and the response to therapy is not always favorable. Recent studies have shown promising results with bortezomib, an inhibitor of proteasomes, and some patients respond to thalidomide. In patients with relapse or refractory to therapy, autologous transplantation may be indicated. The aim of this paper is to describe in detail the current knowledge on the pathophysiology of WM, main clinical manifestations, diagnosis, prognosis and treatment.

Waldenström macroglobulinemia: clinical and immunological aspects, natural history, cell of origin, and emerging mouse models

Waldenström macroglobulinemia (WM) is a rare and currently incurable neoplasm of IgM-expressing B-lymphocytes that is characterized by the occurrence of a monoclonal IgM (mIgM) paraprotein in blood serum and the infiltration of the hematopoietic bone marrow with malignant lymphoplasmacytic cells. The symptoms of patients with WM can be attributed to the extent and tissue sites of tumor cell infiltration and the magnitude and immunological specificity of the paraprotein. WM presents fascinating clues on neoplastic B-cell development, including the recent discovery of a specific gain-of-function mutation in the MYD88 adapter protein. This not only provides an intriguing link to new findings that natural effector IgM⁺IgD⁺ memory B-cells are dependent on MYD88 signaling, but also supports the hypothesis that WM derives from primitive, innate-like B-cells, such as marginal zone and B1 B-cells. Following a brief review of the clinical aspects and natural history of WM, this review discusses the thorny issue of WM's cell of origin in greater depth. Also included are emerging, genetically engineered mouse models of human WM that may enhance our understanding of the biologic and genetic underpinnings of the disease and facilitate the design and testing of new approaches to treat and prevent WM more effectively.

How I treat Waldenström macroglobulinemia

Waldenström macroglobulinemia (WM) is a distinct B-cell disorder resulting from the accumulation, predominantly in the bone marrow, of clonally related IgM-secreting lymphoplasmacytic cells. Genetic factors play an important role, with 20% of patients demonstrating a familial predisposition. Asymptomatic patients should be observed. Patients with a disease-related hemoglobin level less than 10 g/L, platelet count less than 100 × 109/L, bulky adenopathy or organomegaly, symptomatic hyperviscosity, peripheral neuropathy, amyloidosis, cryoglobulinemia, cold-agglutinin disease, or evidence of disease transformation should be considered for therapy. Plasmapheresis should be considered for symptomatic hyperviscosity and for prophylaxis in patients in whom rituximab therapy is contemplated. The use of rituximab as monotherapy or in combination with cyclophosphamide, nucleoside analog, bortezomib, or thalidomide-based regimens can be considered for the first-line therapy of WM and should take into account specific treatment goals, future autologous stem cell transplantation eligibility, and long-term risks of secondary malignancies. In the salvage setting, the reuse or use of an alternative frontline regimen can be considered as well as bortezomib, alemtuzumab, and stem cell transplantation. Newer agents, such as bendamustine and everolimus, can also be considered in the treatment of WM.

Cold antibody autoimmune hemolytic anemias

The cold antibody autoimmune hemolytic anemias (AIHAs) are primarily comprised of cold agglutinin syndrome (CAS) and paroxysmal cold hemoglobinuria (PCH) but, in addition, there are unusual instances in which patients satisfy the serologic criteria of both warm antibody AIHA and CAS ("mixed AIHA"). CAS characteristically occurs in middle-aged or elderly persons, often with signs and symptoms exacerbated by cold. The responsible antibody is of the IgM immunoglobulin class, is maximally reactive in the cold but with reactivity up to at least 30 degrees C. Therapy is often ineffective, but newer agents such as rituximab have been beneficial in some patients. PCH occurs primarily in children, often after an upper respiratory infection. The causative antibody is of the IgG immunoglobulin class and is a biphasic hemolysin that is demonstrated by incubation in the cold followed by incubation at 37 degrees C in the presence of complement. Acute attacks are frequently severe but the illness characteristically resolves spontaneously within a few days to several weeks after onset and rarely recurs. Treatment consists of supportive care, with transfusions frequently being needed.

Cold agglutinins complicating repair of aortic dissection using cardiopulmonary bypass and hypothermic circulatory arrest: case report and review

Cold agglutinins (CAs) are autoantibodies that react reversibly with red blood cells (RBCs) at temperatures of, or below, the thermal amplitude for agglutination. This results in increased blood viscosity and sludging of RBC, and may impair perfusion to various organ systems. Although this phenomenon appears rarely in the clinical arena, the incidence of CA is increased substantially in cardiac surgery due to the routine use of hypothermia for organ preservation and systemic metabolic reduction. Once activated, CA are associated with microvascular occlusion, hemolysis, complement fixation, renal and hepatic insufficiency, cerebral insult, and myocardial infarction. Complications from CA may be minimized with appropriate screening, detection, and management in the perioperative period. A prototypical case is described, and pertinent issues regarding CA are reviewed.

Continual low-level activation of the classical complement pathway

There is evidence that the classical complement pathway may be activated via a "C1-tickover" mechanism, analogous to the C3-tickover of the alternative pathway. We have quantitated and characterized this pathway of complement activation. Analysis of freshly collected mouse and human plasma revealed that spontaneous C3 activation rapidly occurred with the generation of C3 fragments in the plasma. By the use of complement- and Ig-deficient mice it was found that C1q, C4, C2, and plasma Ig were all required for this spontaneous C3 activation, with the alternative complement pathway further amplifying C3 fragment generation. Study of plasma from a human with C1q deficiency before and after therapeutic C1q infusion confirmed the existence of a similar pathway for complement activation in humans. Elevated levels of plasma C3 were detected in mice deficient in complement components required for activation of either the classical or alternative complement pathways, supporting the hypothesis that there is continuous complement activation and C3 consumption through both these pathways in vivo. Blood stasis was found to stimulate C3 activation by classical pathway tick-over. This antigen-independent mechanism for classical pathway activation may augment activation of the complement system at sites of inflammation and infarction.

Pathophysiology of paraprotein production

Paraproteins or monoclonal proteins are the result of clonal B-cell or plasma cell proliferation of a malignant, premalignant or non-malignant nature. Monoclonal proteins may consist of intact immunoglobulin molecules or of heavy or light chains only. Depending on their rate of production and/or secretion they may accumulate in the serum and/or urine of patients. Their presence in the circulation may remain silent, as in monoclonal gammopathy of undetermined significance (MGUS), or may lead to clinical syndromes such as Hyperviscosity, Acrocyanosis, Cold hemagglutination, hemolysis and hemorrhagic manifestations. Their tissue deposition may be localized, with the kidney being the most frequent target as in Myeloma Cast Nephropathy or systemic, as in AL amyloidosis where heart, liver, nerves, tongue are usual targets, in addition to the kidneys.

Guillain-Barré syndrome associated with IgG anti-GM1b antibody subsequent to Mycoplasma pneumoniae infection

Sera from patients with Guillain-Barré syndrome (GBS) frequently have antibodies to various gangliosides. We report a girl with GBS after Mycoplasma pneumoniae infection who had serum IgG antibody to GM1b ganglioside as well as the cold agglutinins. The cold agglutinins are polyclonal IgM autoantibodies to 'I' antigen on erythrocytes. Ganglioside GM1b contains the terminal moiety shared with sialylated I antigen, a main receptor for M. pneumoniae. In this patient, the anti-GM1b antibody may be elicited in a similar mechanism producing anti-I antibody, and functioned in the development of GBS.

Anti–Sia-lb (Anti-Gd) Cold Agglutinins Bind the Domain NeuNAcα2-3Gal in Sialyl Lewisx, Sialyl Lewisa, and Related Carbohydrates on Nucleated Cells and in Soluble Cancer-Associated Mucins

Anti–Sia-lb (formerly anti-Gd) cold agglutinins (CAs) recognize sialylated carbohydrates on both adult and neonate red blood cells (RBCs). RBC CA activity inhibition experiments reported here indicate that the domain NeuNAcα2-3Gal, as found in sialyllactose, synthetic sialyl(s) Lewis(Le)x and sLea, sialyllactosamine, sialyl-fucosyllactose, and nonfucosylated sLea, constitutes the minimal epitope for these CAs, implicating that these autoantibodies could be able to bind this domain in sLex and sLea and related carbohydrates expressed on nucleated cells and in soluble cancer-related mucins. The following data obtained with the previously characterized monoclonal IgMk anti-Sia-lb CA, GAS, show that this is the case. GAS epitope expression among leukocytes that lack sLea parallels that of sLex determinant as detected by mouse monoclonal antibodies (MoAbs), especially MoAb KM-93. It is also found on epithelial malignant cells bearing both sLex and sLea. GAS epitope on these nucleated cells, (1) like that present on RBC, is abolished by sialidase, unaffected by proteases, and inhibited by sialyllactose; and (2) is overlapping and/or proximal to that recognized by anti-sLex MoAb, CSLEX-1, and KM-93. Moreover, CAGAS binds soluble cancer-associated mucins bearing sLex and sLea determinants. This binding is inhibited by sialyllactose and these mucins inhibit the RBC CA activity of CAGAS. The possible significance of anti–Sia-lb (anti-Gd) CAs as autoantibodies directed to carbohydrate ligands of host adhesion molecules that might be receptors of microbial adhesins of some CA-inducing pathogens is discussed.

Anti–Sia-lb (Anti-Gd) Cold Agglutinins Bind the Domain NeuNAcα2-3Gal in Sialyl Lewisx, Sialyl Lewisa, and Related Carbohydrates on Nucleated Cells and in Soluble Cancer-Associated Mucins

Anti–Sia-lb (formerly anti-Gd) cold agglutinins (CAs) recognize sialylated carbohydrates on both adult and neonate red blood cells (RBCs). RBC CA activity inhibition experiments reported here indicate that the domain NeuNAcα2-3Gal, as found in sialyllactose, synthetic sialyl(s) Lewis(Le)x and sLea, sialyllactosamine, sialyl-fucosyllactose, and nonfucosylated sLea, constitutes the minimal epitope for these CAs, implicating that these autoantibodies could be able to bind this domain in sLex and sLea and related carbohydrates expressed on nucleated cells and in soluble cancer-related mucins. The following data obtained with the previously characterized monoclonal IgMk anti-Sia-lb CA, GAS, show that this is the case. GAS epitope expression among leukocytes that lack sLea parallels that of sLex determinant as detected by mouse monoclonal antibodies (MoAbs), especially MoAb KM-93. It is also found on epithelial malignant cells bearing both sLex and sLea. GAS epitope on these nucleated cells, (1) like that present on RBC, is abolished by sialidase, unaffected by proteases, and inhibited by sialyllactose; and (2) is overlapping and/or proximal to that recognized by anti-sLex MoAb, CSLEX-1, and KM-93. Moreover, CAGAS binds soluble cancer-associated mucins bearing sLex and sLea determinants. This binding is inhibited by sialyllactose and these mucins inhibit the RBC CA activity of CAGAS. The possible significance of anti–Sia-lb (anti-Gd) CAs as autoantibodies directed to carbohydrate ligands of host adhesion molecules that might be receptors of microbial adhesins of some CA-inducing pathogens is discussed.

Cardiac surgery and cold-reactive proteins

Cold agglutinins are commonly found in sera of healthy persons. They rarely become clinically apparent due to their activity at low temperatures. In these patients, cardiovascular operations requiring hypothermia can result in complications such as hemolysis, renal failure, and myocardial damage and can cause unexpected morbidity and mortality. The literature on cold-reactive proteins is reviewed, and methods of diagnosis and management related to cardiac surgery are suggested. Ideally all patients should be routinely tested preoperatively for the antibodies, and appropriate changes in cardiopulmonary bypass and myocardial management plans should be made in positive patients. Preoperative plasmapheresis may be a useful adjunct, especially in patients requiring operation under profound hypothermia and circulatory arrest. Currently, warm heart surgery appears to be the most expedient method. Unexpected detection of agglutination during operation or hemolysis after operation requires a specific treatment plan.

Cold agglutinins: preoperative diagnosis leads to an uneventful perfusion

This report presents the successful use of normothermic cardiopulmonary bypass (CPB) and warm continuous retrograde cardioplegia to facilitate coronary artery bypass grafting (CABG) in a patient with cold agglutinins. As a result of their agglutinating action and resultant haemolysis, cold-reactive autoantibodies have the potential for causing morbidity and mortality when a patient is placed on hypothermic CPB and the heart is arrested with profoundly cold cardioplegia. The crux of the situation is to keep the temperature above the critical temperature of the cold agglutinin; this technique guarantees accomplishing that goal.

Waldenström's macroglobulinemia with an IgM paraprotein that is both a cold agglutinin and a cryoglobulin and has a suppressive effect on progenitor cell growth

BACKGROUND

A patient with Waldenström's macroglobulinemia was admitted to the hospital with fever, leg pain, and dyspnea. The patient had gas gangrene of the left leg that required above-the-knee amputation. Plasmapheresis was instituted to treat hyperviscosity.

STUDY DESIGN AND METHODS

The patient's serum contained an IgM-kappa paraprotein, a cryoglobulin, and a cold agglutinin. The serum was studied.

RESULTS

The patient's red cells typed as A1, Rh-positive. The direct antiglobulin test was negative. The serum contained a cold agglutinin with anti-Pr cold agglutinin specificity (titer 4096). Maximal thermal range was 30 degrees C. Following dithiothreitol treatment, the cold agglutinin activity disappeared. The serum IgM concentration in the tested sample was 62.3 g per L. The cold agglutinin titer in the supernatant after removal of the cryoglobulin was 256, and the IgM level was 0.31 g per L. Redissolving the cryoglobulin in a equivalent volume of saline resulted in a cold agglutinin titer of 4096 and an IgM level of 68.4 g per L. These results indicate that the cryoglobulin and the cold agglutinin are the same paraprotein. Serum protein electrophoresis using agarose gel and immunofixation of the serum revealed an IgM-kappa monoclonal band. Progenitor cell assays were performed by adding the patient's serum at final concentrations of 0, 1, 5 and 10 percent (vol/vol) to patient's and normal donor's peripheral blood mononuclear cells. Inhibition of burst-forming units-erythroid and colony-forming units-granulocyte/macrophage by the patient's serum was demonstrated. Appropriate controls and the use of the serum of another patient with Waldenström's macroglobulinemia did not suppress progenitor cell growth. The patient's serum inhibited colony formation in a dose-response fashion.

CONCLUSION

Reports of cryoprecipitable cold agglutinins are rare. This case is unusual because the IgM-kappa paraprotein was also a cold agglutinin with anti-Pr specificity and erythroid and granulocyte-macrophage progenitor cell-suppressive properties.

Use of retrograde cold crystalloid cardioplegia in a patient with unexpected cold agglutination

Undetected cold agglutinins were encountered in a patient undergoing coronary artery bypass grafting using antegrade cold blood cardioplegia. Macroemboli were infused into the coronary arterial tree. These were flushed out by the use of retrograde cold crystalloid cardioplegia. Activated cold agglutinins may be hazardous in cold blood cardioplegia.

Cardiac operation without hypothermia for the patient with cold agglutinin

Recently, a new technique for myocardial protection that does not rely on hypothermia has been reported. In this method, the heart is continuously perfused with normothermic hyperkalemic blood cardioplegia during the cross-clamp period. Cardiac arrest is achieved and maintained using high levels of potassium. Hypothermia is not part of this technique; thus, the danger of hypothermia can be avoided in the patient with cold agglutinin disease without compromising myocardial protection. This communication reports our experience using retrograde continuous normothermic blood cardioplegia in one patient with potent cold agglutinins and severe coronary artery occlusive disease. This patient experienced an uneventful operative and postoperative course and remains asymptomatic, now more than two years after operation.

Mechanism of autoimmune hemolytic anemia in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a malignant clonal expansion of CD5+B lymphocytes. The CD5+B lymphocytes have been postulated to produce autoantibodies. CLL patients may demonstrate features of autoimmunity including autoimmune hemolytic anemia. However, the origin of the autoantibodies causing the hemolysis is not clear. The present studies were performed to determine whether these autoantibodies are the products of the neoplastic B-CLL clones. Immunoglobulins (Ig) were eluted from washed red blood cells (RBC) obtained from two CLL patients at the time they had autoimmune (DAT-direct antiglobulin test-positive) hemolytic anemia. The light chain phenotypes of these eluted autoantibodies were determined and found to be monotypic with exact correlation to the light chain expressed on the surface of the B-CLL clones. Elutions from RBC of DAT negative patients or normal volunteers failed to demonstrate measurable amounts of Ig. In contrast, Ig eluted from RBC obtained from SLE patients with DAT positive hemolytic anemia found to be polyclonal autoantibodies exhibiting both light chain types. Furthermore, CD5+B lymphocytes obtained from the same two CLL patients (DAT+) produce, in vitro understimulation with phorbal myristate acetate (PMA), monoclonal antibodies which react and bind to RBC. Thus these studies provide direct evidence demonstrating that the antibodies causing the autoimmune hemolytic anemia in our two CLL patients are the products of the B-CLL neoplastic clones.

Idiotypic heterogeneity of VKIII autoantibodies to red blood cell antigens

VKIII light (L) chains are commonly expressed by human autoantibodies with diverse binding specificities, including red blood cell antigens. To better understand the physiologic and pathologic expression of these L chain variable region genes, we have created a panel of murine monoclonal anti-idiotypic antibodies by immunization with a human lymphoblastoid B cell line that secretes an IgM VKIII autoantibody specific for the I red blood cell carbohydrate determinant. The binding specificities of these nine murine monoclonal antibodies, termed IV.1-IV.9, were evaluated against a large panel of monoclonal Ig proteins and compared to two previously well-characterized monoclonal anti-idiotypes, 6B6.6 and 17.109; these two anti-idiotypes have been shown to primarily identify VKIII rheumatoid factors derived from the kv328 (VKIIIa) and kv325 (VKIIIb) genes, respectively. In contrast, our anti-idiotypic antibodies identified (public) cross-reactive idiotypes present on many VKIII proteins that included both anti-erythrocyte and rheumatoid factor autoantibodies. Certain anti-idiotypic antibodies (IV.2 and IV.6) were restricted to VKIIIa L chains but differed from the 6B6.6 anti-idiotype by binding to a larger subset of VKIIIa proteins representing the products of at least two VKIIIa genes. One antibody of our panel (IV.5) recognized a private idiotope expressed only by the immunizing antibody. Using the panel of anti-idiotypic antibodies to evaluate erythrocyte autoantibodies with different serologic specificities, we found striking heterogeneity of L chain idiotype expression, even among known VKIII anti-i/I autoantibodies. These findings differ from the recently described structural and idiotypic conservation associated with the H chain of anti-i/I autoantibodies. From correlations of idiotypic reactivity with L chains of known sequence, it is postulated that the observed heterogeneity of L chain idiotype expression is due to differences in the genetic origin and/or somatic diversification of L chain variable region genes. Furthermore, subtle variability of L chain structure may contribute in part to the differences in fine binding specificity among anti-I and anti-i autoantibodies.

Complement activation by cold agglutinins

Purified monoclonal human IgM cold agglutinins (CA) of different specificities (anti-I, anti-i, anti-Pr) were investigated for their complement-activating capacity in a homologous system. Incubation of human RBC with excess of IgM CA in the cold, and subsequently with human serum at 37 degrees C, resulted in striking differences in hemolysis. Hemolysis did not correlate to the amount of antibodies bound to RBC at 4 or 20 degrees C. Despite the hemolytic inefficiency of anti-i and anti-Pr CA tested, C1 fixation and subsequent activation of the classical pathway of complement could be assessed in all cases. Absolute numbers of C3 molecules bound to RBC, exceeding the critical level to initiate the terminal sequence of the complement cascade, could not fully explain the differences in the hemolytic activity of the CA. Since C8 binding protein (C8bp) carries I determinants it is hypothesized that anti-I-induced complement-mediated hemolysis might also be favored by the binding of the autoantibody to and probably steric hindrance of this major regulatory protein of the terminal complement sequence. The prominent role of homologous restriction of complement-mediated lysis as a protective mechanism can also be deduced from the fact that rabbit as well as rat serum as a source of heterologous complement lysed cold agglutinin-sensitized red blood cells more efficiently than human serum.

[Two-dimensional electrophoretic study of monoclonal gammopathies and cold agglutinins associated with a chronic hemolytic anemia]

Two-dimensional gel electrophoresis (2-DGE) associated with a very sensitive silver staining is one of the most powerful technique available for protein analysis. Proteins are separated in the first dimension by isoelectric focusing in a pH gradient, and in the second dimension by polyacrylamide gel electrophoresis. Proteins are thus separated according to their charge and to their size. The high resolution of 2-DGE allows the analysis of complex mixture of proteins with a great reproducibility. More than hundred different proteins can be individualized after 2-DGE of plasma or serum samples. Using this technique, we analysed samples obtained from normal donors and from patients with different gammopathies. Our results confirm that the heavy chains of immunoglobulins are easily detected and that the alpha, gamma and mu chains are clearly differentiated from one another. The typical polyclonal heavy and light chains appear as indiscrete spots after staining of the gels. On the contrary, the monoclonal chains appear as discrete spots. Monoclonal heavy chains have a restricted charge heterogeneity. We also analysed cold agglutinins, partially purified from plasma of three patients showing evidence of chronic hemolysis, a positive direct antiglobulin test of the complement type and anti-I autoantibodies. The 2-DGE have clearly demonstrated that these cold agglutinins were monoclonal IgM, when these later were not detectable by immunofixation electrophoresis. We think that the 2-DGE is a very usefull specialized aid to the analysis of such particular immunohematological problems.

Relationship of variable region genes expressed by a human B cell lymphoma secreting pathologic anti-Pr2 erythrocyte autoantibodies

To study the biology of cold agglutinin disease we previously established EBV-transformed B cell clones isolated from a patient with splenic lymphoma of an early plasmacytic cell type and immune hemolysis due to an anti-Pr2 cold agglutinin. These clones had an aberrant chromosomal marker identical to the patient's B cell lymphoma and each secreted IgMk anti-Pr2 similar to the pathologic autoantibody in the serum of the patient. In this study, we have further investigated the Pr2-specific autoimmune response through nucleotide sequencing of VH and VL region genes. We have shown that the seven clones share the same VDJ/VJ gene segments and junctional elements confirming their clonal origin. The VH sequences were 88% homologous to a VHI germline gene while the VL sequences were 97% homologous to a VkIII germline gene. Only 4 somatic mutations (3 silent and 1 conservative) were found in greater than 5,000 bp sequenced, suggesting that a low mutation rate existed. Based on a tumor mass of 10(12) cells and a minimum of 40 divisions, we estimated the somatic mutation rate to be 4.45 x 10(-5) m/bp/d. This somatic mutation rate is similar to those estimated for acute lymphocytic leukemia (pre-B cell) and chronic lymphocytic leukemia (intermediate B cell), but significantly lower than the mutation frequency in follicular lymphomas (activated B cell). We propose that the difference in somatic mutation frequency of a B cell tumor may be related to the stage of B cell differentiation. In addition, the low mutation frequency observed in the Pr2-specific B cell tumor may also reflect, in part, selection by autoantigen to conserve sIg structure and specificity.

Use of a total wash-out method in an open heart operation

Pathological cold agglutinins may induce hemolysis in patients who need hypothermic cardiopulmonary bypass and blood transfusion. A simple technique, termed the total wash-out method, was used in a patient with high thermal amplitude, moderate-titer cold agglutinin before hypothermic cardiopulmonary bypass. The patient's cold agglutinin titer decreased abruptly after operation. None of the preoperative hemolysis phenomena were found during her 6 months of follow-up.

Comparative biochemical and genetic characterization of clonally related human B-cell lines secreting pathogenic anti-Pr2 cold agglutinins

To study the biology of cold autoimmune hemolytic anemia, Epstein-Barr virus (EBV)-transformed B-cell clones were established from a patient with splenic lymphoma associated with immune hemolysis due to an anti-Pr2 cold autoantibody. Studies were performed comparing the cold autoantibody present in culture supernatants of these cell lines to the pathogenic cold autoantibodies present in the patient's plasma. Cytogenetic studies of splenic lymphocytes demonstrated an abnormal karyotype (51XX, +3, +9, +12, +13, +18). After EBV transformation, eight clones secreting IgM, kappa anti-Pr were isolated; each clone had the same abnormal karyotype as above. DNA isolated from the clones and spleen was analyzed by Southern blot hybridization with JH, C mu, and C kappa probes; identical gene rearrangements were seen in each case. Anti-Pr antibodies, isolated from culture supernatant and serum were compared by isoelectric focusing (IEF) and demonstrated similar banding patterns. Distinctive binding patterns, however, were observed in 2/8 clones, suggesting structural differences. Adsorption studies with red blood cells further showed that the observed IEF banding patterns were solely due to anti-Pr cold autoantibody. With a thin-layer chromatography method, the biochemical determinants recognized by the cold autoantibodies were defined as glycolipids containing Neu Ac alpha 2-3Gal beta 1-4Glc sequences. The data demonstrate that the autoantibodies of the EBV-transformed B-cell lines were similar to the pathogenic monoclonal serum autoantibody in both structure and specificity. These clonal cell lines may thus serve to further study the biology of human B-cell lymphomas with defined autoantibody specificity.

Mononucleosis-like syndrome associated with a multisystem Coxsackie virus type B3 infection in adolescence

We describe a severe multisystem Coxsackie virus type B3 infection in a previously healthy 14-year-old girl who presented with a mononucleosis-like syndrome (MS). Initial observations included a prominent cervical lymphadenopathy, exudative pharyngitis and leucocytosis with atypical lymphocytosis. At the end of the 2nd week of illness the patient developed meningoencephalomyelitis and haemolytic anaemia. Subclinical myocarditis was also recorded. Prolonged hepatitis recrudescing at the time of recovery coincided with serological evidence of a reactivated Epstein-Barr virus infection. The diagnosis was based on a significant rise in serum antibody titres against Coxsackie virus type B3, using the neutralization test. Intrathecal synthesis of antibodies to Coxsackie virus type B3 was also demonstrated. Generalized Coxsackie virus infections in adolescence are rare and an MS has not, to our knowledge, been associated with Coxsackie virus type B3 infection.

Antibodies to sulfated glucuronic acid containing glycosphingolipids in neuropathy associated with anti-MAG antibodies and in normal subjects

Serum of patients with neuropathy and IgM monoclonal antibodies (M-proteins) that bind to the myelin-associated glycoprotein (MAG) were tested for binding to the major cross-reactive sulfated glucuronic acid containing glycosphingolipid, sulfated glucuronic acid paragloboside (SGPG). IgM binding to the glycolipid was detectable at serum dilutions of 1:10,000 and reactivity was greatest at 4 degrees C. Low titers of IgM binding to the glycolipid were also detected in sera from normal subjects and from patients with neurologic or rheumatologic diseases without serum M-proteins. Binding activity was present in 25% of the sera tested, and titers ranged between 1:25 and 1:400. One patient with peripheral neuropathy, however, had a measurable titer of 1:12,800 in the absence of monoclonal gammopathy. The study indicates that cold reacting anti-SGPG IgM antibodies are frequent constituents of the normal human antibody repertoire, and that monoclonal or polyclonal expansion of B cells that secrete these antibodies, is associated with peripheral neuropathy.

Benefit of a 37 degree C extracorporeal circuit in plasma exchange therapy for selected cases with cold agglutinin disease

Plasmapheresis is commonly advocated in cold agglutinin disease with life-threatening hemolysis. Some clinicians, however, are reluctant to use this therapy because of perceived technical problems and risks attendant with the temperature of the extracorporeal circulation. In this study we report our experience of two patients with severe life-threatening hemolysis and in whom plasma exchange was not feasible due to red blood cell autoagglutination in the extracorporeal circuit. A method is described involving the use of blood warmers and the Fenwal CS-3000 blood cell separator with its 37 degrees C centrifuge compartment. The use of plasma exchange in this manner is a safe and beneficial form of adjunctive therapy and should be considered for patients with cold agglutinin disease at risk for extracorporeal agglutination or hemolysis.

Evans' syndrome as a presenting manifestation of atypical paroxysmal cold hemoglobinuria

Paroxysmal cold hemoglobinuria is a rare and potentially life-threatening acquired hemolytic anemia occurring either as an acute transient anemia following several different viral syndromes, or in a chronic idiopathic form. Episodic hemolysis in paroxysmal cold hemoglobinuria is usually associated with a biphasic (Donath-Landsteiner) IgG cold-reactive complement-fixing autohemolysin with anti-P specificity. Paroxysmal cold hemoglobinuria has not previously been associated with malignancy nor has it been clearly shown to be steroid-responsive. This report describes a patient with steroid-responsive autoimmune hemolytic anemia and immune thrombocytopenia (Evans' syndrome) associated with oat cell carcinoma of the lung and a unique biphasic anti-IgM autohemolysin. This case extends the spectrum of biphasic antibody-mediated immune cytopenias and widens both the clinical and the serologic definition of paroxysmal cold hemoglobinuria.

Failure of histiocytosis X cells to express i blood group antigen

Expression of HLADR, I, i blood group antigen and T6 antigen were studied in Histiocytosis X cells and pulmonary alveolar macrophages using double labelling immunofluorescence technique or immuno-peroxidase procedure. Alveolar macrophages express simultaneously HLADR and i blood group antigen. Histiocytosis X cells, characterized by HLADR and T6 antigens, and by their ultra-structural marker do not express i antigen. These results confirm the hypothesis that histiocytosis X cells constitute a specialized sub-population of the mononuclear phagocyte system.

Glycosphingolipid carriers of carbohydrate antigens of human myeloid cells recognized by monoclonal antibodies

Six monoclonal antibodies with known specificities for the carbohydrate antigens i, X or Y, and seven anti-myeloid antibodies (determinants unknown) selected for their differing reaction patterns with human leucocytes were tested in chromatogram binding assays for reactions with myeloid cell glycolipids derived from normal human granulocytes and chronic myelogenous leukemia cells. Antigenicities were found exclusively on minor glycolipids which were barely or not at all detectable with orcinol-sulphuric acid stain. Among these, a neutral glycosphingolipid bound the anti-i antibody Den and chromatographed as the ceramide octasaccharide, Gal beta 1----4GlcNac beta 1----3Gal beta 1----4GlcNac beta 1----3Gal beta 1----4GlcNAc beta 1----3Gal beta 1----4Glc-Cer. Several species of neutral glycosphingolipids with six to more than ten monosaccharides were detected which carry the X antigen and others the Y antigen: Gal beta 1----4(Fuc alpha 1----3)GlcNAc and Fuc alpha 1----2Gal beta 1----4(Fuc alpha 1----3)GlcNAc, respectively. In addition, three new types of carbohydrate specificities were detected among the myeloid cell glycolipids. Two were associated with neutral glycolipids: the first, recognised by anti-myeloid antibodies VIM-1 and VIM-10, was expressed on a distinct set of glycolipids with six or more monosaccharides, and the second, recognized by VIM-8, was expressed on glycolipids with more than ten monosaccharides. The third specificity, recognised by the anti-myeloid antibody VIM-2, was expressed on slow migrating sialoglycolipids with backbone structures of the poly-N-acetyllactosamine type that are susceptible to degradation with endo-beta-galactosidase. Thus, we conclude that the i and Y antigens occur among the glycolipids of normal myeloid and chronic myelogenous leukemia cells and that a high proportion of hybridoma antibodies raised against differentiation antigens of myeloid cells are directed at carbohydrate structures.

Rapid purification of anti-I and anti-i cold antibodies by affinity chromatography

A method is described for the rapid purification of serologically active high titer anti-I and anti-i cold antibodies from the sera of patients with chronic cold agglutinin disease (CCAD). The purification procedure is based on thermal affinity chromatography, using desialated orosomucoid (alpha 1-acid glycoprotein)-Sepharose 4B conjugated beads. The nature of the interaction between the cold agglutinins (CA) and the desialated orosomucoid is unknown. Inhibition studies, however, revealed that the cold hemagglutinating activities of all the anti-i sera were inhibited by desialated orosomucoid while only 1 out of 4 of the anti-I sera was similarly affected. Anti-I or anti-i antibodies were separated from whole sera in 7 out of 7 samples with a recovery in most cases of 100% of the cold hemagglutinating activity. The resultant products were purified monoclonal IgM fractions which could react with anti-kappa and anti-mu but not with anti-lambda sera. The homogeneity, purity and specificity of all preparations were confirmed by immunodiffusion analysis against purified I and i blood group antigens isolated from human erythrocyte membranes, zonal and right-angle electrophoresis and hemagglutination or hemagglutination inhibition studies.

Interaction of Mycoplasma pneumoniae with erythrocyte glycolipids of I and i antigen types

The role of sialoglycolipids (gangliosides) as receptors for the human pathogen Mycoplasma pneumoniae was investigated by using purified gangliosides of known carbohydrate structures as inhibitors of the binding of 51Cr-labeled erythrocytes to sheet cultures of M. pneumoniae. We found that sialoglycolipids with long carbohydrate backbones of the poly-N-acetyllactosamine type were more potent inhibitors of M. pneumoniae binding than those with short carbohydrate chains. This is in accord with earlier inhibition data for glycoproteins and oligosaccharides. Thus, the inhibitory activity of a fraction of bovine erythrocyte gangliosides containing long backbone structures of I antigen type was approximately 200 times greater than that of the short chain gangliosides GM3 and GT1b. The binding of M. pneumoniae to erythrocytes of I and i antigen types was found to be comparable, indicating that M. pneumoniae in its adhesive specificity may not distinguish between the branched carbohydrate backbones of I type and the linear structures of i type. Thus, the production of autoantibodies to the backbone structures of I type rather than i type after infection with this agent may simply reflect a greater abundance of branched carbohydrate receptors of I type on the surface of host cells with which the mycoplasma forms immunogenic complexes.

Autoimmune hemolysis: a critical review

Autoimmune hemolysis is defined as a shortening of erythrocyte lifespan due to antibodies directed against the individuals own red cells. This autoantibody production (by B lymphocytes) is thought to result from deficient activity of suppressor T lymphocytes. The rate of erythrocyte destruction depends on the properties of the autoantibodies and on the activities of the complement and mononuclear phagocyte systems: anemia results when destruction outweighs marrow production. Autoimmune hemolysis, which may be primary or secondary, is classified into "warm," "cold," and "mixed" types. The hemolysis associated with pregnancy. Donath-Landsteiner antibodies, of mixed type, and in children, is treated in detail. Current treatment is with immunosuppressive drugs, surgery, and plasma exchange, though immunomanipulation may become important in the future; blood transfusion may be a life-saving adjunct to other therapy.

Species differences in the expression of carbohydrate differentiation antigens on mammalian blood cells revealed by immunofluorescence with monoclonal antibodies

Following recent observations using monoclonal antibodies that carbohydrate structures behave as differentiation antigens of man and mouse, we have made a preliminary survey of the expression of 8 monoclonal antibody-defined carbohydrate antigens on blood cell smears of man, baboon, mouse, rat, rabbit, pig, and dog. There are considerable species differences in the patterns of antigen expression. However, certain generalizations can be made as follows: the i and I antigens, associated with linear and branched carbohydrate chains consisting of repeating N-acetyl-lactosamine sequences (Gal beta 1-4GlcNAc, termed Type-2 backbone sequences) are widely distributed among granulocytes and lymphocytes of all the species studied, and on erythrocytes, monocytes, and platelets of some of them. Substantial amounts of Type-1 backbone sequences (Gal beta 1-3GlcNAc) may occur on rabbit lymphocytes. The N-acetylneuraminic acid-containing antigens, Pr2 and Gd, are also expressed to varying degrees on blood cells. On the other hand, antigens based on mono- and difucosylated N-acetyllactosamine, termed SSEA-1 (or X-hapten) and C14 (or Y-hapten) are predominantly granulocyte/monocyte-associated antigens. The former antigen is expressed in overt form only on untreated human granulocytes but occurs in cryptic state, masked by sialic acid, on human monocytes, and on the granulocytes and monocytes of baboon, rabbit, and dog but not on those of mouse, rat, and pig. The latter antigen is expressed on human granulocytes and on neuraminidase-treated monocytes and granulocytes of dog. Lymphocytes of dog are unusual in their expression of C14 antigen, in cryptic state, masked by sialic acid residues. Although the physiological roles of these various carbohydrate structures, in vivo, are not yet known, they seem excellent candidates as determinants of species and cell-type differences in susceptibilities to infective agents.