T gamma (T gamma) cells suppress growth of erythroid colony-forming units in vitro in the pure red cell aplasia of B-cell chronic lymphocytic leukemia

Mutational heterogeneities in STAT3 and clonal hematopoiesis-related genes in acquired pure red cell aplasia

Dysregulation of T cell-mediated immunity is considered a major pathophysiological mechanism in acquired pure red cell aplasia (PRCA), including idiopathic PRCA, large granular lymphocytic leukemia-associated PRCA, and thymoma-associated PRCA. Although STAT3 mutations are frequently detected in PRCA patients, the roles of other mutational profiles and their impact on clinical characteristics remain unclear. In this study, whole-exome sequencing and targeted sequencing using a custom-designed panel were performed on 53 PRCA patients. The most frequently mutated genes were STAT3 (36%), PCLO (9%), TET2 (9%), NEB (6%), DNMT3A (6%), and POT1 (6%). Based on genetic profiles, patients were classified into three groups: those with STAT3 variants (group S), those without STAT3 variants but with variants in clonal hematopoiesis (CH)-related genes (group C), and those without variants in either STAT3 or CH-related genes (group O). Patients in group O had a higher median age compared to group S, while group S exhibited milder anemia severity than group C. Additionally, POT1 variants were associated with the idiopathic subtype of PRCA in females, often co-occurring with STAT3 variants. Variants in CH-related genes and other genes, including STAT3 and POT1, may play crucial roles in the pathophysiology of PRCA.

[Pure red cell aplasia: Diagnosis, classification and treatment]

Pure red cell aplasia (PRCA) is a rare anemia characterised by profound reticulocytopenia caused by a marked reduction in bone marrow erythroblasts, without abnormalities in other blood lineages. Blackfan-Diamond anemia is an inherited ribosomopathy responsible for a hereditary form of PRCA. Acquired PRCA are separated in primary and secondary forms, including Parvovirus B19 infection, thymoma, lymphoproliferative disorders, autoimmune diseases (lupus) and drug-induced PRCA. The pathophysiology of PRCA is not fully understood and involves both humoral and T lymphocyte autoreactive cells. In Parvovirus B19-related PRCA, treatment is based on polyvalent immunoglobulins. Thymectomy for thymoma is mandatory but results in prolonged remission in a limited number of cases. The therapeutic strategy is based on expert opinion: corticosteroids in monotherapy provide few sustained responses. The choice of an additional immunosuppressant drug is guided by the presence of an underlying disease. In most cases, cyclosporine A is the first choice providing the best response rate but requires a concentration monitoring (150 to 250 ng/mL). The second choice is cyclophosphamide in large granular lymphocyte leukaemia. Sirolimus (mTOR inhibitor) seems to be a promising option especially in refractory cases. Transfusion independence is the main objective. If the patient receives numerous red blood cell transfusions (> 20 packs), iron overload assessment is crucial to initiate an iron chelation. A retrospective and prospective national cohort (EPIC-F) has been set up and is now available to include each case of PRCA to improve the knowledge of this disease and to optimize the therapeutic strategy.

T cell clonal expansion and STAT3 mutations: a characteristic feature of acquired chronic T cell-mediated pure red cell aplasia

Acquired chronic pure red cell aplasia (PRCA) develops idiopathically or in association with other medical conditions, including T cell large granular lymphocytic leukemia (T-LGLL) and thymoma. T cell dysregulation is considered a cardinal pathogenesis of PRCA, but genetic-phenotypic associations in T cell abnormalities are largely unclear. We evaluated an extended cohort of 90 patients with acquired PRCA, including 26 with idiopathic, 36 with T-LGLL-associated and 15 with thymoma-associated PRCA, for their T cell immuno-phenotypes, clonalities and STAT3 mutations. TCR repertoire skewing of CD8⁺ T cells was detected in 37.5% of idiopathic, 66.7% of T-LGLL-associated and 25% of thymoma-associated PRCA patients, and restriction to Vβ1 was most prominent (41%). Clonalities of TCRβ or γ chain and STAT3 mutational status were statistically associated (P = 0.0398), and they were detected in all three subtypes. The overall response rate to cyclosporin A was 73.9%, without significant difference by subtypes nor STAT3 mutational status. The T cell dysregulations, such as TCR repertoire skewing with predominant Vβ1 usage, clonality and STAT3 mutations, were frequently found across the subtypes, and the close associations between them suggest that these T cell derangements reflect a common pathophysiological mechanism among these PRCA subtypes.

Pathophysiologic Mechanisms And Management Of Large Granular Lymphocytic Leukemia Associated Pure Red Cell Aplasia

Large granular lymphocytic leukemia (LGLL) is a chronic clonal lymphoproliferative disease of mature T or NK cells, and produces a variety of hematological abnormalities. Pure red cell aplasia (PRCA) is a rare haematological disease and is one of the most common complications of LGLL. LGLL-associated PRCA may represent a relatively indolent type and may be more common than reported, but its natural history and clinical course have not been well described. The ethnic origin of the patients is an important consideration in determining the relationship between PRCA and LGLL. Guidelines and progresses for management of LGLL-associated PRCA rely on accumulation of empirical experiences, integrative analyses of several cases and clinical trials. The purpose of this review is to evaluate occurrence, possible mechanisms, diagnosis, clinical features, treatments and outcomes of LGLL-associated PRCA.

Secondary autoimmune cytopenias in chronic lymphocytic leukemia

Secondary autoimmune cytopenias in chronic lymphocytic leukemia are distinct clinical entities that require specific management. These autoimmune disorders have a complex pathogenesis that involves both the leukemic cells and the immune environment in which they exist. The mechanism is not the same in all cases, and to varying degrees involves the chronic lymphocytic leukemia (CLL) cells in antibody production, antigen presentation, and stimulation of T cells and bystander polyclonal B cells. Diagnosis of autoimmune cytopenias can be challenging as it is difficult to differentiate between autoimmunity and bone marrow failure due to disease progression. There is a need to distinguish these causes, as prognosis and treatment are not the same. Evidence regarding treatment of secondary autoimmune cytopenias is limited, but many effective options exist and treatment can be selected with severity of disease and patient factors in mind. With new agents to treat CLL coming into widespread clinical use, it will be important to understand how these will change the natural history and treatment of autoimmune cytopenias.

Autoimmune cytopenias in chronic lymphocytic leukemia

The clinical course of chronic lymphocytic leukemia (CLL) may be complicated at any time by autoimmune phenomena.The most common ones are hematologic disorders, such as autoimmune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP). Pure red cell aplasia (PRCA) and autoimmune agranulocytosis (AG) are, indeed, more rarely seen. However, they are probably underestimated due to the possible misleading presence of cytopenias secondary to leukemic bone marrow involvement or to chemotherapy cytotoxicity. The source of autoantibodies is still uncertain, despite the most convincing data are in favor of the involvement of resting normal B-cells. In general, excluding the specific treatment of underlying CLL, the managementof these complications is not different from that of idiopathic autoimmune cytopenias or of those associated to other causes. Among different therapeutic approaches, monoclonal antibody rituximab, given alone or in combination, has shown to be very effective.

Diagnosis and management of acquired pure red cell aplasia

Pure red cell aplasia is a syndrome characterized by a severe normocytic anemia, reticulocytopenia, and absence of erythroblasts from an otherwise normal bone marrow. Although the causes and natural course of this syndrome are variable and although the anemia in some patients can be managed by treatment of an underlying inflammatory or neoplastic disease, the pathogenesis of a large number of cases is autoimmune, including those associated with thymoma, and are best managed with immunosuppressive therapy.

Chronic Lymphocytic Leukemia-Associated Pure Red Cell Aplasia

Pure red cell aplasia (PRCA) is a well-known marrow failure which may be acquired or constitutional/congenital, as the Diamond-Blackfan syndrome. Acquired PRCA may show as a primary hematological disorder or secondary to an associated disease, infection or drug. PRCA rarely complicates chronic lymphocytic leukemia (CLL), may occur anytime in the course of the disease and, in this context, it is a minority of total PRCA. Anemia due to PRCA in CLL patients must be carefully evaluated and differentiated from other causes (autoimmune hemolytic anemia, neoplastic lymphocyte infiltration of bone marrow, chemotherapy) that require a different therapeutic approach. PRCA is thought to be an immunologically mediated disorder, but there is no uniformity in the setting of the management. Immunosuppressive therapy is frequently given, such as steroids and cyclosporin-A. Recently, anecdotal cases have been published on the effectiveness of monoclonal antibodies rituximab and alemtuzumab.

Is pure red cell aplasia (PRCA) a clonal disorder?

Pure red cell aplasia (PRCA) is an uncommon disorder, many cases lacking a well defined aetiology. This report describes three cases of PRCA (two idiopathic and one associated with B-CLL) who were investigated to assess the possibility of their PRCA being associated with a clonal proliferation of T-lymphocytes. The results show that one patient had evidence of T-cell receptor (TCR) gamma chain rearrangement, and the other had a TCR delta chain rearrangement. These two cases raise the possibility of PRCA being associated with a clonal proliferation of T-cells and further studies are warranted.

Pure red cell aplasia and myelofibrosis in B-cell neoplasm

We describe an unusual case of B-cell neoplasm accompanied by pure red cell aplasia (PRCA) and myelofibrosis in a 67-year-old male presenting with severe anaemia. A few unclassified, myeloperoxidase-negative blastoid cells were seen on bone marrow aspiration, and erythroid cell hypoplasia and myelofibrosis on bone marrow biopsy. An autoimmune PRCA was suspected, as serum CH50, C3 and C4 levels were consistently low. Ciclosporin was effective in treating the anaemia, but anaemia returned when the drug was discontinued. Thirteen months later, the patient was admitted with pleural effusion and ascites that contained monoclonal CD19+ CD20+ immature blast cells with a complex karyotype, thought to be neoplastic B-cells. The unclassified blastoid cells seen earlier may therefore have been from the same origin. The patient deteriorated rapidly and died. Only one case of non-Hodgkin's lymphoma with PRCA and myelofibrosis has been reported previously. We discuss the possibility that dysregulated T-cells induced by neoplastic B-cells may have given rise to concomitant PRCA and myelofibrosis.

Successful treatment of refractory pure red cell aplasia associated with lymphoproliferative disorders with the anti-CD52 monoclonal antibody alemtuzumab (Campath-1H)

Acquired pure red cell aplasia (PRCA) is a rare, but significant, complication of lymphoproliferative disorders. It is characterized by anaemia, absence of red cell precursors in the bone marrow and normal granulopoiesis and megakaryopoiesis. We describe two patients with refractory pure red cell aplasia associated with chronic lymphocytic leukaemia (CLL) and a large granular CD8 T-lymphocytic leukaemia (LGL) respectively. Both patients had failed multiple treatment regimens for PRCA and were transfusion dependent. Both patients were subsequently treated with the anti-CD52 humanized monoclonal antibody, alemtuzumab, receiving total doses in excess of 300 mg. Response to treatment, as documented by a rapid increase in the reticulocyte count, occurred as early as the third infusion. At the time of this report, both patients remain in complete remission with normal haemoglobin levels. Alemtuzumab appears to be an effective and well-tolerated therapy for pure red blood cell aplasia associated with lymphoproliferative disorders.

Pure red cell aplasia in a Sjögren's syndrome/lupus erythematosus overlap patient

Hematological complications of systemic lupus erythematosus usually include anemia of chronic disease and peripheral destruction of blood cells. We describe the case of a young woman with Sjögren's syndrome'lupus erythematosus overlap, mother of infant with congenital heart block, complicated by pure red cell aplasia. The patient was asymptomatic until the onset of severe anemia. A serum inhibitor of erythropoiesis was detected before the onset of immunosuppression. Bone marrow examination showed a low CD4:CD8 ratio, an immune defect possibly linked with the unrestrained production of antibodies against erythroid progenitor cells.

Chronic lymphocytic leukemia presenting in association with aplastic anemia

An unusual case of chronic lymphocytic leukemia presenting in association with aplastic anemia is discussed, along with a review of the few previously reported cases. Possible humoral and cellular autoimmune mechanisms are examined as possible causes of marrow aplasia in this setting.

Successful treatment of pure red cell aplasia with rituximab in patients with chronic lymphocytic leukemia

Pure red cell aplasia (PRCA) is a rare complication in patients with chronic lymphocytic leukemia (CLL). It is characterized by reticulocytopenia and by an absence of red cell precursors in the bone marrow. Unlike autoimmune hemolytic anemia, which is characterized by an increased number of reticulocytes, positive Coombs test findings, and a high serum level of lactate dehydrogenase. Two patients with B-cell CLL are reported to have developed PRCA, one while on chemotherapy with fludarabine and one seeking treatment for de novo PRCA. Both responded dramatically to therapy with monoclonal antibody rituximab (Rituxan) in a short period of time and continued to be transfusion-independent. These are the first 2 reported patients for whom rituximab treatment for PRCA in CLL was successful, and this treatment deserves further investigation.

Recovery of erythropoiesis following allogeneic bone marrow transplantation for chronic lymphocytic leukaemia-associated pure red cell aplasia

Pure red cell aplasia is a rare condition, that can be either idiopathic or associated with a lymphoproliferative disorder. The latter is considered to result from T cell-mediated suppression of haematopoiesis, and usually responds well to treatment with immunosuppressive medication. We describe a patient with B-CLL-associated pure red cell aplasia who did not respond to several courses of immunosuppressive treatment. Erythropoiesis was finally restored after allogeneic bone marrow transplantation.

Autoimmune disorders of erythropoiesis

Immune-mediated disorders of erythropoiesis can result in acquired severe anemia, low reticulocyte counts, and bone marrow exhibiting pure red cell aplasia or ineffective erythropoiesis. Erythropoiesis can be suppressed or impaired by humoral or cellular mechanisms. In vitro inhibition of erythroid colony growth by immunoglobulins or lymphocytes can be a strong argument for the immune origin of the disease. Classical etiologies are thymoma and hematologic malignancies such as chronic lymphocytic leukemia (CLL). Clonal proliferation of T cells has been incriminated. Recently, acquired circulating autoantibodies directed against erythropoietin have been detected in a case of pure red cell aplasia. Autoimmune mechanisms have also been detected or suggested in synartesis and in Fas-associated dyserythropoiesis, two distinct syndromes recently described where morphologic abnormalities specific to the erythroid lineage illustrate ineffective erythropoiesis.

Management of chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is the most common form of adult leukaemia in Western countries. The diagnosis requires mature-appearing lymphocytes in the peripheral blood to >5 x 10(9)/L. The immunophenotype typically includes B cell antigens CD19, CD20 and CD23, low expression of surface immunoglobulin and CD5+, with other T cell antigens absent. Bone marrow biopsy, although not required for diagnosis, must show at least 30% lymphocytes. Cytogenetic abnormalities are frequent in patients with CLL, and may be associated with poor prognosis. Clinically, most patients are asymptomatic at presentation, with incidental lymphadenopathy and/or hepatosplenomegaly in the routine physical examination. Infections by opportunistic pathogens are the major cause of death. Aggressive transformation occurs in 10% of patients with CLL, most commonly prolymphocytic leukaemia (PLL) and Richter's syndrome. PLL de novo must be differentiated from PLL of an aggressive transformation. The incidences of autoimmune diseases and solid or haemopoietic secondary malignancies are increased in patients with CLL. Clinical stage is the strongest prognostic factor in CLL. There is no indication for early intervention. The current recommendation to start treatment includes disease-related symptoms, massive and/or progressive hepatosplenomegaly or lymphadenopathy, increasing bone marrow failure, autoimmune disease, and recurrent infections. Alkylating agents (e.g. chlorambucil) and nucleoside analogues (e.g. fludarabine) are the most active agents for CLL. Fludarabine induces higher response rates, but no improvement in overall survival has been observed. Fludarabine is the drug of choice for the majority of patients with CLL. Chlorambucil may be helpful for elderly patients with poor performance, and for patients who do not tolerate fludarabine. No drug combination is better than single agents. For patients refractory to initial treatment, referral to a clinical trial is the best choice. Other salvage therapy includes retreatment with the same initial agent (chlorambucil or fludarabine) if initial response was observed, or fludarabine for patients refractory to chlorambucil. Promising new approaches include cycle-active agents, nelarabine, biological therapy such as anti-CD52 monoclonal antibody, bone marrow transplantation, including the use of submyeloablative preparative regimens ('minitransplant') to induce graft-versus-leukaemia effect, and gene therapy. Prophylactic antibacterials and intravenous immunoglobulin should not be used routinely during supportive care. Epoetin may be helpful for patients who have anaemia without obvious cause. Assessment of response to therapy in CLL has been updated by the National Cancer Institute Working Group, and these guidelines are used worldwide for clinical trials.

Clinical and laboratory evidence for a trilineage haematopoietic defect in patients with refractory Diamond-Blackfan anaemia

Diamond-Blackfan anaemia (DBA) is a constitutional pure red cell aplasia presenting in early childhood. In some patients, neutropenia and/or thrombocytopenia have also been observed during the course of the disease. We have followed 28 patients with steroid-refractory DBA for up to 13 years with serial peripheral blood counts and bone marrow (BM) aspirates and biopsies. In 21/28 (75%) patients, moderate to severe generalized BM hypoplasia developed, with overall cellularities ranging from 0% to 30%. Marrow hypoplasia correlated with the development of neutropenia (9/21; 43%) and/or thrombocytopenia (6/21; 29%) in many patients. No patient had either cytogenetic abnormalities or progressed to acute leukaemia, although one 13-year-old developed marked marrow fibrosis and trilineage dysplasia. We used the in vitro long-term culture-initiating cell (LTC-IC) assay to quantify multilineage, primitive haematopoietic progenitors in a representative subset of these patients. LTC-IC assays showed equivalent frequencies of cobblestone area-forming cells (CAFCs) with a mean of 5.42/10(5) cells +/- 1.9 SD and 6.13/10(5) cells +/- 2.6 SD in nine patients and six normal controls respectively. The average clonogenic cell output per LTC-IC, however, was significantly lower in DBA patients (mean 2.16 +/- 1.2 SD vs. 7. 36 +/- 2.7 SD in normal controls, P = 0.0008). Our results suggest that the underlying defect in patients with severe refractory DBA may not be limited to the erythroid lineage, as was evidenced by the development of pancytopenia, bone marrow hypoplasia and reduced clonogenic cell output in LTC-IC assays.

Clonal T cell proliferation in patients with pure red cell aplasia

Among the patients with idiopathic pure red cell aplasia (PRCA) who do not meet the diagnostic criteria of chronic lymphocytic leukemia, there are some cases which suggest an association with clonal T lymphocytic proliferation. The morphological characteristics and responses to treatment revealed two distinct groups among the present 13 patients. The lymphocytes in one group were typical granular lymphocytes of T cell phenotype which were treated effectively with cyclophosphamide rather than cyclosporine. The response to therapy in this group occurred after a perceptible reduction in lymphocyte mass, which took at least 8 weeks. The lymphocytes in the second group consisted mainly of non-granulated lymphocytes or some granulated lymphocytes with fine and indistinct granules and responded well to cyclosporine therapy. A reduction in lymphocytes mass was not a prerequisite for the development of the remission of red cell aplasia in this group, and responses occurred within 4 weeks. Clonal T cell proliferation was detected in some patients, which raised the possibility of idiopathic PRCA being associated with a clonal proliferation of T cells. Distinguishing lymphocytes in patients with PRCA could potentially be used to plan treatment strategy and assess prognosis.

Selective effect of cyclosporine monotherapy for pure red cell aplasia not associated with granular lymphocyte-proliferative disorders

Morphological characteristics of lymphocytes and the response to cyclosporine treatment have revealed some unique patients with pure red cell aplasia. Lymphocytes from these patients consisted mainly of non-granulated lymphocytes. All of the patients were successfully managed by cyclosporine monotherapy irrespective of prior treatment. A reduction in lymphocyte mass was not a prerequisite for the remission of pure red cell aplasia, and responses occurred within 1 month from the start of therapy. Clonal T-cell proliferation was detected in four patients, which raised the possibility of idiopathic pure red cell aplasia being associated with a clonal proliferation of T cells. An examination of the lymphocytes in patients with pure red cell aplasia could potentially be used to plan better therapeutic modalities and assess prognosis.

Acquired pure red cell aplasia in Japan

We reviewed the clinical features of 150 patients with acquired pure red cell aplasia (PRCA) in Japan. There were 35 patients with acute type and 115 with chronic type PRCA. Of the acute PRCA patients, 17 had human parvovirus B19 infection. Drug-induced PRCA was demonstrated in 7 patients. Of the 115 patients with chronic PRCA, 51 patients were classified as primary and 64 cases were associated with miscellaneous diseases such as thymoma, a variety of hematological disorders and collagen diseases. Among the hematological disorders, PRCA was most frequently seen in granular lymphocyte proliferative disorders (GLPD). The erythroid colony growth patterns from bone marrow were variable. The serum erythropoietin level was high in most patients. Various kinds of treatment were tried for the chronic PRCA cases. Cyclosporin A (CyA) was the most effective form of treatment and the response rate was 82% (31/38). Twenty-three of 37 patients (62%) responded to bolus methylprednisolone therapy. The largest number of patients were treated with oral prednisolone, and the therapy was effective in 27 of the 55 (49%). The response rate to cyclophosphamide was only 29% (5/17), but in combination with prednisolone, half of the patients (7/14) responded to the therapy. CyA is recommended as the first-line therapy for acquired chronic PRCA.

Pure red cell aplasia with thymona: evidence of T-cell clonal disorder

Pure red cell aplasia (PRCA) sometimes accompanies thymoma. Herein, we report a PRCA patient with thymoma with a clonal disorder of T cells. A 55-year-old man presented with anemia and anterior mediastinum tumor. The laboratory study revealed hemoglobin 8.2 g/dl; leukocytes 15.8 x 10(9)/L with 76.5% neutrophils, 20.0% lymphocytes, and reticulocytes 0.0%. Bone marrow aspirate smears and biopsy sections revealed normal myeloid and megakaryocyte differentiation and contained no erythroid precursors. We made the diagnosis of PRCA. The size of the lymphocytes was small without any granules in the cytoplasm. The surface marker of peripheral blood mononuclear cells demonstrated increased CD2+, CD3+, CD4-, and CD8+ populations. The mediastinal tumor was resected and a thymoma diagnosed. A monoclonal rearrangement of T-cell receptor (TCR)-beta-chain gene was found using Southern blot analysis of the mononuclear cells in both peripheral blood and thymoma. Treatment with prednisolone, thymectomy, and cyclophosphamide exerted no beneficial effect. After initiation of the Cyclosporin A therapy, the patient developed reticulocytosis. This PRCA case seems to present a neoplastic proliferation of CD8+ T cells in peripheral blood and thymus with a monoclonal rearrangement of the TCR-beta-chain gene.

Cyclosporine A in chronic lymphocytic leukemia: dual anti-leukemic and immunosuppressive role?

The association of hemolytic anemia and other autoimmune cytopenias with chronic lymphocytic leukemia (CLL) is well known. The etiology of these immune syndromes is still uncertain, despite evidence that the putative cell of origin of the B-CLL cell produces naturally occurring autoantibodies. Cyclosporine A is effective in treating the immune manifestations associated with CLL and, occasionally, has shown anti-leukemic activity. We report two cases in which cyclosporine A treatment of autoimmune hemolytic anemia resulted in reduction of CLL cell burden. We then discuss the possible mechanism of action of cyclosporine A and the nature of the autoimmune processes involved.

Pure red cell aplasia after chemotherapy for Hodgkin's lymphoma: in vitro evidence for T cell mediated suppression of erythropoiesis and response to sequential cyclosporin and erythropoietin

Acquired pure red cell aplasia (PRCA) has been associated with various lymphoproliferative conditions but its occurrence with Hodgkin's disease is rare. We report a case of PRCA occurring immediately following the completion of induction chemotherapy in a patient with Stage IIIB nodular sclerosing Hodgkin's disease. In vitro erythroid colony studies documented evidence for T cell mediated suppression of erythropoiesis and lack of a serum inhibitor. Addition of cyclosporin to the in vitro cultures stimulated erythroid colony growth. Following in vivo treatment with cyclosporin peripheral blood CD4/CD8 ratios returned to normal. However, serum erythropoietin levels were inappropriately low. Subsequent treatment with erythropoietin induced a reticulocytosis and transfusion independence. Since discontinuing the erythropoietin, the patient has been able to maintain a hemoglobin of 100 g/L. This case illustrates that red cell aplasia occurring in the setting of Hodgkin's disease may be due to T cell mediated suppression of erythropoiesis. A response to cyclosporin may be masked by inappropriately low erythropoietin levels.

Cyclosporine and prednisone therapy for pure red cell aplasia in patients with chronic lymphocytic leukemia

We describe the characteristics of response to treatment with cyclosporine (CYA) plus prednisone in seven episodes of pure red cell aplasia (PRCA) in four patients with B cell chronic lymphocytic leukemia (CLL). Fourteen episodes of PRCA occurred in four patients with CLL. Eleven episodes were treated with conventional therapies which included an alkylating agent and prednisone. Four episodes that failed to respond to conventional therapies and an additional three episodes were treated with CYA and prednisone. Six of the seven episodes, including three of four which had failed conventional therapies, responded to CYA plus prednisone compared with six of eleven episodes treated with conventional therapies. Response to CYA and prednisone occurred without a reduction in leukemic mass. In contrast, PRCA remission did not occur until after leukemic mass reduction in three of four patients treated successfully with conventional therapies. Time to response was shorter (14 +/- 3 days) with CYA plus prednisone than with conventional therapies (154 +/- 97 days) in three of four patients. These results indicate that CYA plus prednisone is an effective therapy for the induction of remission from PRCA in patients with CLL.

Bone marrow aplasia in B cell chronic lymphocytic leukaemia: successful treatment with antithymocyte globulin

Pure red cell aplasia is a rare but well known association of chronic lymphocytic leukaemia (CLL). Pancytopenia due to bone marrow aplasia has not been previously described in CLL. A 42 year old man with B cell CLL became severely pancytopenic with bone marrow aplasia. Bone marrow culture resulted in a greatly reduced colony formation. High dose corticosteroids and intravenous immunoglobulin treatment were unsuccessful. Prompt and complete marrow recovery ensued after administration of antithymocyte globulin.

Hemopoietic inhibition in hairy cell leukemia

Leukopenia, thrombocytopenia, and anemia are important features of hairy cell leukemia (HCL). They are generally considered to be due to hypersplenism and to inadequate production by bone marrow which is heavily infiltrated by the neoplastic hairy cells (HC). However, the cytopenias may also be caused by hemopoietic inhibition by cytokines derived from the mononuclear cells (MNC) of HCL. We studied the MNC of HCL with an in vitro assay for granulocyte-macrophage progenitors (CFU-GM) to search for this hemopoietic inhibitor(s) and to determine the cell source and mechanism of its production/release. We found that MNC conditioned media from 7 of 9 HCL cases exerted substantial inhibitory effect (23% to 66%) on normal marrow cells. Peak inhibitory activity was obtained in media conditioned with 10(6) MNC/ml for 90 minutes to 24 hours. Both HC and lymphocytes could release inhibitor(s) through mutually synergistic cell interactions. HC alone were inactive and lymphocytes alone were only weakly active. Mixtures of conditioned media of HC and of lymphocytes were not synergistic. The lymphocytes responsible for the inhibition were present in preparations depleted of cells bearing the cluster designation 4 antigen (CD4+) and B cells and were most likely the CD8+ T-cells. In one patient so examined, a partial reversal of inhibition was achieved by treating MNC-CM with antibodies to tumor necrosis factor (TNF)-alpha suggesting that TNF-alpha was at least partly involved in the inhibition of CFU-GM. This mechanism of cytokine release may be operative in vivo to account for the cytopenias in HCL and, if so, could alter the concept of hypersplenism in this disease.

Pure red cell aplasia associated with B cell lymphoma: demonstration of bone marrow colony inhibition by serum immunoglobulin

A 58-year old male with follicular small cleaved B cell lymphoma developed pure red cell aplasia (PRCA) during chemotherapy. To understand the etiology of the PRCA, we studied the effects of patient sera on the progenitor cell colony formation of normal human bone marrow cells in vitro. We demonstrated a marked inhibition of normal bone marrow progenitor cell colony formation by patient sera, but not pooled normal human sera. Immunoglobulin was then precipitated from patient sera for similar studies. The majority of the precipitated immunoglobulin was of the IgG type. The immunoglobulin fraction markedly inhibited normal bone marrow progenitor cell colony formation, whereas the non-immunoglobulin fraction was not inhibitory. The presence of inhibitory serum immunoglobulin correlated with the hematologic status of the patient. We conclude that the development of PRCA in patients with B cell lymphoma may be due to a serum IgG inhibitor of bone marrow progenitor cell growth.

Resolution of pure red cell aplasia and lymphoma: response to intravenous gammaglobulin and combination chemotherapy

Pure red cell aplasia (PRCA) rarely occurs in nonthymic lymphoproliferative disorders. This report describes the clinical course and therapy of a patient with a history of Sjogren syndrome who developed well-differentiated lymphocytic lymphoma associated with PRCA and severe hemolytic anemia. Life-threatening hemolytic anemia combined with the presence of multiple antibodies and lack of erythroid precursors was treated successfully with a single dose of intravenous gammaglobulin. A sustained, complete remission and normalization of the bone marrow was achieved following six courses of an aggressive chemotherapy regimen. Thus, occasionally low-grade lymphomas can produce life-threatening complications, requiring a more aggressive therapeutic intervention than those routinely applied.

Large granular lymphocytes from B-chronic lymphocytic leukemia patients inhibit normal B cell proliferation

Large granular lymphocytes (LGL) may exert regulatory influences on B cell immunoglobulin synthesis. We, therefore, investigated the influence of LGL from controls and B cell chronic lymphocytic leukemia patients (B-CLL) on control B cell proliferation to costimulation with the F(ab')2 fragment of goat antihuman mu and B cell growth factor (BCGF). Purified LGL (greater than 90% by morphology) from control and B-CLL peripheral blood were added in various concentrations to purified control B cells and incubated with anti-mu and BCGF for 3 days. [3H]-thymidine uptake of B cells was then measured. There was no proliferation of control or CLL LGL alone to the costimulatory signals of the F(ab')2 fragments of goat antihuman mu chain and BCGF. Addition of control LGL to equal numbers of control B cells did not blunt control B cell responsiveness to BCGF (with control LGL 8,649 +/- 298 cpm vs. control B cells alone 8,336 +/- 556 cpm, mean +/- SEM). When control LGL were increased to 10:1 LGL:B cell ratio, the maximal inhibition by control LGL of control B cell proliferative response to BCGF was 23%. In contrast, addition of CLL LGL at a 1:1 LGL:B cell ratio resulted in marked impairment of the control B cell proliferative response to BCGF (with CLL LGL 3,586 +/- 954 cpm vs. control B cells alone 8,649 +/- 298 cpm). Inhibition by CLL LGL occurred in a cell-concentration-dependent manner. No difference in CLL LGL's inhibitory effect on either resting or activated control B cell responsiveness to BCGF was noted. Inhibition of de novo protein synthesis (by cycloheximide inhibition) of CLL LGL did impair CLL LGL's inhibitory capacity for BCGF-induced B cell proliferation. A possible explanation for these findings includes the possibility that a subgroup of LGL with B cell suppressive activity may have expanded as a host response to the B cell leukemia or as part of the disordered cell regulation in B-CLL.

Cyclosporin-A therapy of pure red cell aplasia in a patient with B-cell chronic lymphocytic leukemia

A 65-year-old woman with B-cell chronic lymphocytic leukemia (CLL) and pure red cell aplasia (PRCA) is described. After initial chemotherapy with three different regimens over 3 months (prednisone, chlorambucil/vincristine, cyclophosphamide, bleomycin/cyclophosphamide, etoposide, prednisone), normalization of the blood lymphocyte count was observed, but lymphocyte infiltration of the bone marrow persisted and erythropoiesis remained virtually absent. Monotherapy with cyclosporin-A (CyA) was begun. After 35 days, a marked increase in the reticulocyte count was observed, and with continuing therapy, there was a rapid increase in the hemoglobin level. Follow-up after 13 months of uninterrupted treatment with CyA revealed remission of both CLL and PRCA. CyA should be investigated further as a therapeutic modality for PRCA in patients with CLL, and such trials might provide further clues to the pathogenesis of this peculiar association.

Malignant chronic lymphocytic leukemia B cells elaborate soluble factors that down-regulate T cell and NK function

To determine if the frequently observed T cell and natural killer dysfunction in B-chronic lymphocytic leukemia might be related to the presence of large numbers of malignant B cells, we studied the effects of secretory or shed products of CLL B cells on normal (control) T cell and NK function. The cell-free supernatants from CLL B cells cultured from 24 to 48 hr inhibited a variety of T cell functions including: PHA-induced proliferation, PHA-stimulated entry of T cells into the cell cycle, and PHA-induced production of interleukin-2. In addition, B-CLL supernatants diminished control NK activity. Purified control B cells and other malignant cell lines produced little or no inhibitory activity toward these T cell or NK functions. The sera from these same B-CLL patients diminished PHA-induced interleukin-2 production by control T cells. Initial molecular characterization of the inhibitory factor(s) revealed it to be of low molecular weight (less than 5000 daltons) with loss of functional activity after treatment with neuraminidase. This suggested that this substance might be either a ganglioside or glycoprotein whose inhibitory activity depends on the presence of a sialic acid moiety. If CLL B cells are capable of secreting or shedding immunosuppressive factor(s), then alteration of this property may result in a more normal immune system for these patients.

A study of splenic irradiation in chronic lymphocytic leukemia

A retrospective study was performed to assess the effect of splenic irradiation (SI) on splenomegaly, splenic pain, anemia, and thrombocytopenia in patients with chronic lymphocytic leukemia. Twenty-two patients received 32 courses of SI. Of 31 courses of SI given for splenomegaly there were 19 responders (61%). Ten courses of SI were given for splenic pain resulting in partial relief of pain in 4 courses and complete relief in 4 courses. Only 4 of 16 courses given for anemia resulted in elevations of hemaglobin of 2 g/dL or more. Of the 14 courses of SI given for thrombocytopenia there were only 2 responses with platelet counts decreasing further in another 9 courses. The median duration of response was 14 months (range: 3-116 months). There was no dose-response relationship detected for SI in CLL. Treatment related toxicity was hematologic and secondary to leucopenia and thrombocytopenia. We recommend the use of small fraction sizes of 25 cGy to 50 cGy and close monitoring of hematological parameters. Splenic irradiation effectively palliates splenomegaly and reduces spleen size in CLL. It was of limited value in correcting anemia and thrombocytopenia in this patient population.

Biology of natural killer cells

Studies of cytotoxicity by human lymphocytes revealed not only that both allogeneic and syngeneic tumor cells were lysed in a non-MHC-restricted fashion, but also that lymphocytes from normal donors were often cytotoxic. Lymphocytes from any healthy donor, as well as peripheral blood and spleen lymphocytes from several experimental animals, in the absence of known or deliberate sensitization, were found to be spontaneously cytotoxic in vitro for some normal fresh cells, most cultured cell lines, immature hematopoietic cells, and tumor cells. This type of nonadaptive, non-MHC-restricted cellmediated cytotoxicity was defined as “natural” cytotoxicity, and the effector cells mediating natural cytotoxicity were functionally defined as natural killer (NK) cells. The existence of NK cells has prompted a reinterpretation of both the studies of specific cytotoxicity against spontaneous human tumors and the theory of immune surveillance, at least in its most restrictive interpretation. Unlike cytotoxic T cells, NK cells cannot be demonstrated to have clonally distributed specificity, restriction for MHC products at the target cell surface, or immunological memory. NK cells cannot yet be formally assigned to a single lineage based on the definitive identification of a stem cell, a distinct anatomical location of maturation, or unique genotypic rearrangements.

Impaired interleukin-2 production by T-lymphocytes in polycythemia vera

T-lymphocyte function was investigated in a group of eight patients with polycythemia vera (PV) and 13 normals. Responsiveness of T-cells to stimulation by mitogen was significantly impaired in the PV patients (p = .02). Analysis of immune cell subpopulation composition by assessment of cell surface phenotype did not reveal imbalances that could account for impaired T-cell proliferative ability in PV patients. Addition of recombinant human interleukin-1 to PV mononuclear cell cultures did not enhance proliferative ability. Addition of recombinant human interleukin-2 to cultures had no effect on maximum mitogen stimulation in normals but significantly improved responses in PV patients (p less than .02), correcting them to normal levels. Measurement of interleukin-2 production by stimulated cultured mononuclear cells confirmed subnormal IL-2 production by PV T-cells (p less than .00005). Impaired IL-2 production could conceivably contribute to the pathogenesis of PV by limiting the ability of IL-2-dependent cells to regulate hematopoiesis.

Treatment of pure red cell aplasia with ciclosporin: suppression of activated T suppressor/cytotoxic and NK-like cells in marrow and blood correlates with haematological response

In pure red cell aplasia (PRCA), suppression of erythropoiesis is most probably effected by cellular and/or antibody-mediated immune mechanisms. We have prospectively investigated the patterns of activated T-lymphocyte subsets and natural killer (NK)-like cells in the bone marrow (BM) and peripheral blood (PB) of 6 PRCA patients prior to and during treatment with the T-cell selective immunosuppressive drug Ciclosporin (CS; Cyclosporin-A). Before CS therapy, large proportions of circulating activated HLA-DR+ T-suppressor/cytotoxic cells (28%, 11-41; median and range), DR+ T-helper cells (7%, 4-13) and cytoplasmic interferon-gamma+ (IFN-gamma) lymphocytes (20%, 9-33) were found in PRCA, but were barely detectable in healthy controls. Similarly, high levels of activated T cells were present in patient marrows. Initiation of CS therapy resulted in rapidly decreasing levels of activated T cells and NK cells both in PB and in BM. During follow-up of individual patients, an inverse relationship was observed between the haematological response to CS and the levels of activated T-suppressor/cytotoxic cells, IFN-gamma+ lymphocytes (in PB and BM) and NK-like cells (in BM). The present correlations indicate a pathogenetic role of phenotypically activated T-suppressor/cytotoxic cells and possibly NK-like cells in PRCA. During successful treatment with CS, these cell types are reduced in numbers but reappear in relapse. Our results also pinpoint the clinical value of monitoring activated T-cell subsets for the prediction of immunological remission in PRCA and related disorders.

The role of antilymphocyte globulin in the treatment of chronic acquired bone marrow failure

Antilymphocyte globulin is an immunoglobulin preparation prepared from heterologous serum after the animal (horse or rabbit) has been immunised with human lymphocytes, obtained from the thymus (antithymocyte globulin, ATG) or thoracic duct (antilymphocyte globulin, ALG). The rationale for the use of ALG in the treatment of chronic acquired marrow failure is based on its immunosuppressive activity and the fact that a proportion of cases of bone marrow failure, whether affecting single or multiple haemopoietic cell lines are due to immune-mediated suppression of haemopoiesis. In addition, in vitro studies have shown that ALG also has an immunostimulatory effect on lymphokine and haemopoietic growth factor production, and may therefore directly stimulate haemopoietic progenitor cells. ALG has been used for the treatment of aplastic anaemia and acquired chronic marrow failure affecting single cell lines namely pure red cell aplasia (PRCA), amegakaryocytic thrombocytopenia and chronic neutropenia due to immune inhibition of granulopoiesis ('acquired white cell aplasia'). ALG is used for treatment of non-severe aplastic anaemia (NSAA) and in those cases of severe aplastic anaemia (SAA) where allogeneic transplantation is not possible or is not indicated. Treatment with ALG results in 75% long term survival for NSAA and 40-50% for SAA although there is a very severe subgroup of SAA defined by peripheral blood neutrophils of less than 0.2 x 10(9)/l who rarely benefit from ALG therapy. For those patients who do not respond a second course of ALG can be given later using ALG from a different animal source.(ABSTRACT TRUNCATED AT 250 WORDS)

Autoimmunity in chronic lymphocytic leukaemia

Seventy-nine patients with chronic lymphocytic leukaemia were evaluated for the presence of autoimmune diseases and autoantibodies. One patient has polymyositis and two additional patients presented with features suggestive of pernicious anaemia and chronic active hepatitis. The Coombs' direct test was positive in 7% and immune thrombocytopenia was present in 8.1% of patients. Five (7%) patients had M-protein in the serum. No increased frequency of other autoantibodies was noted in our study group. We conclude that the propensity to develop antibodies is restricted only to the haematopoietic system and that there is no increased frequency of non-haematological autoimmune diseases in chronic lymphatic leukaemia.

Methylprednisolone therapy in aplastic anaemia: correlation of in vitro tests and lymphocyte subsets with clinical response

20 patients with aplastic anaemia were treated with methylprednisolone 1 g/d for 3 d followed by prednisolone 60 mg on alternate days. At 3 months after therapy, 7 of 20 patients (35%) showed recovery, 2 had died and 11 were non-responders. Only newly diagnosed patients were responders. Results of in vitro tests were correlated with clinical response. The first test was designed to determine whether removing various subpopulation of cells would increase the numbers of progenitor cells. In the second test blood cells were collected at 1 month after starting treatment and assayed for progenitor cells. Data from both tests did not correlate with the response to therapy. Lymphocyte subsets were measured in the blood before and at 1 month after treatment. The absolute numbers of OKT3+, OKT4+ and OKT8+ cells were significantly decreased compared to the normal population. The number of HNK1+ cells was also decreased but no significant difference was observed. Responders had a higher number of HNK1+ cells compared to non-responders. No significant differences of OKT3+, OKT4+ and OKT8+ cells among responders and non-responders were observed. Therefore a high number of HNK1+ cells prior to therapy may identify patients responding to the treatment.