Idiopathic Cytopenia Research Articles

Flow Cytometry Is Highly Predictive In Excluding Myelodysplastic Syndromes In Patients With Indeterminable Cytopenia: A Prospective Analysis Of 316 Patients

Myelodysplastic syndromes (MDS) constitute a heterogeneous group of hematopoietic stem cell disorders, characterized by ineffective hematopoiesis resulting in cytopenias and a variable risk to develop acute myeloid leukemia. Discrimination between MDS and non-clonal causes of cytopenia is regularly based on cytomorphology (CM) and conventional cytogenetics (CCG) and can be challenging in case of minor morphologic dysplastic features or if karyotypic abnormalities are lacking. In these cases an integrated multi-diagnostic approach is warranted.The aim of this prospective study was to investigate the role of flow cytometry (FC) compared to other diagnostic tools in MDS. We evaluated bone marrow samples of 316 patients with unexplained cytopenias, who were routinely analyzed by CM and FC combined with CCG, i.e. karyotyping or interphase fluorescence in situ hybridization (iFISH) when karyotyping failed. CM as gold standard classified 82 patients as MDS and 114 patients as non-clonal diseases while in 120 patients the diagnosis was indeterminate. Four patients were classified as normal. CCG analysis was normal in 192 patients, abnormal in 58 patients (MDS-associated abnormalities in 28), and not performed in 66 patients because there was no indication based on the CM result. Additional iFISH analysis in 4 patients where CCG failed, showed no abnormalities. FC analysis, performed according to European LeukemiaNet guidelines (Van de Loosdrecht et al., Haematologica 2009 and Leukemia 2012), disclosed MDS in 90 patients, showed signs of dysmyelopoiesis in 74 patients, and no signs of MDS in 141 patients (Van de Loosdrecht et al., J. Natl Compr Canc Net 2013). FC as diagnostic tool in MDS reached a sensitivity of 83% and a specificity of 77%; the positive predictive value of FC was 78% and the negative predictive value was 83%, when compared to outcome of the multi-diagnostic approach in which CM was leading.Focusing on the patient population with indeterminable CM (N=120), CCG analysis identified 1 patient with a chronic lymphatic leukemia associated abnormality and 5 patients with typical MDS abnormalities (Schanz et al., JCO 2012). The latter were also recognized by FC. In the remaining 114 CM-inconclusive cases, where CCG did not add to the diagnosis (note: ∼60% of MDS patients have normal karyotypes) FC identified 11 patients with a typical MDS profile, 28 patients with dysmyelopoiesis and 69 patients without any signs of dysmyelopoiesis. Based on the negative predictive value of FC (83%, as described above), we postulate that most of these 69 inconclusive cytopenic cases are no MDS. These cases might be classified as idiopathic cytopenia of unknown significance (ICUS), in the absence of other causes.In summary, this prospective single center study analyzed the integrated diagnostic work-up of patients with unexplained cytopenias. We demonstrated that FC is instrumental in discriminating clonal and non-clonal causes of cytopenia by excluding underlying MDS when validated standard diagnostic tools such as CM and CCG are not informative. Disclosures:No relevant conflicts of interest to declare.

P-066 Idiopathic cytopenia of undetermined significance with non-MDS-associated cytogenetic abnormalities

P-066 Idiopathic cytopenia of undetermined significance with non-MDS-associated cytogenetic abnormalities

THE USE OF MONOCLONAL ANTIBODIES IN THE TREATMENT OF AUTOIMMUNE COMPLICATIONS OF CHRONIC LYMPHOCYTIC LEUKEMIA

Autoimmune cytopenias are a frequent complication in CLL, occurring in approximately 5–10% of the patients. The most common manifestation is autoimmune haemolytic anaemia, followed by immune thrombocytopenia and only rarely pure red blood cell aplasia or autoimmune granulocytopenia. Initial treatment is as for the idiopathic autoimmune cytopenias, with most patients responding to conventional corticosteroid therapy. Patients, who do not respond to conventional therapy after 4–6 weeks, should be considered for alternative immunosuppression, monoclonal antibody therapy or splenectomy. While randomized trials demonstrating the benefit of rituximab in CLL-related autoimmune diseases are still lacking, there are considerable data in the literature that provide evidence for its effectiveness.The monoclonal antibody alemtuzumab also displays considerable activity against both the malignant disease and the autoimmune complication in patients with CLL, although at the expense of greater toxicity. A number of new monoclonal antibodies, such as ofatumumab, GA-101, lumiliximab, TRU-016, epratuzumab, and galiximab, are currently investigated in CLL and their activity in CLL-related autoimmune cytopenias should be evaluated in future studies.

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.

Idiopathic cytopenia of undetermined significance and systemic lupus erythematosus

Idiopathic cytopenia of undetermined significance and systemic lupus erythematosus

Idiopathic cytopenia of undetermined significance and systemic lupus erythematosus

Idiopathic cytopenia of undetermined significance (ICUS) is characterized as less than 10% of dysplasias with less than 5% blasts in the bone marrow, however, it may be present heterogeneously. Until the present, only a small number of cases have been published and knowledge about the mechanisms and prognosis is scarce(1). Systemic lupus erythematosus (SLE) is an autoimmune disease that affects multiple organ systems, including the bone marrow(2). Data on changes in the bone marrow in patients with SLE are scarce and inconsistent, but mainly involve hypoplasia, hyperplasia, vasculitis, lymphocytosis/plasmacytosis, myelofibrosis, pure red cell aplasia and dyserythropoiesis. Dysplastic changes in all hematopoietic lineages and peripheral cytopenias have also been described in SLE patients; however, they seem to be reversible with remission of the disease(2,3). Figure 1 illustrates a case of one 18-year-old female patient with persistent refractory cytopenia and mild dysplasia in the three hematopoietic lineages compatible with ICUS. After three years of follow up she was strongly positive for antinuclear antibodies and evolved with glomerulonephritis, characterizing SLE. Figures 2A & B illustrate the cytogenetic analysis with karyotyping by G-band and Fluorescence in situ Hybridization (FISH) for 5q- negative.

Myelodysplastic syndrome versus idiopathic cytopenia of undetermined significance: the role of morphology in distinguishing between these entities

Myelodysplastic syndrome (MDS) is a heterogeneous group of diseases characterized by ineffective and dysplastic hematopoiesis and pancytopenia in the peripheral blood(1). Minimal diagnostic criteria for MDS have been discussed by several working groups. The term idiopathic cytopenia of undetermined significance (ICUS) has been proposed to define patients who do not fill minimal criteria for MDS but present with persistent cytopenia not attributable to a hematological or non-hematological disease(2). In medical services where immunohistochemistry, cytogenetics and studies of progenitor cell assays are still not available, the morphologic parameters may be the center of the diagnosis of ICUS. Several working groups have also discussed minimal morphological criteria for 'bone marrow dysplasia'. Based on these discussions, at least 10% of all cells in a given lineage should produce signs of dysplasia to fill this important criterion(3). Patients with ICUS present mild dysplasia in one or more hematopoietic lineages. Figures 1 & 2 illustrate the myelogram of one patient with ICUS and one patient with MDS showing the levels of dysplasia in both settings. Distinguishing between these entities is important to understand the similarities and differences in pathologic mechanisms of the two hematologic diseases and so to direct the correct management of patients.

Low blood counts: immune mediated, idiopathic, or myelodysplasia

AbstractTraditionally, cytopenias are classified as deficiency mediated, immune mediated, BM failure induced, renal, or idiopathic, with the latter including the so-called idiopathic cytopenias of undetermined significance (ICUS). Clinical findings, symptoms, blood counts, BM findings, and other laboratory parameters are usually sufficient to reveal the type and cause of a marked cytopenia. However, in patients with chronic mild cytopenia, it may be a challenge for the physician to establish a correct diagnosis. In such patients, laboratory features and findings often reflect a diagnostic interface, so that criteria that are otherwise robust may hardly be applicable or are not helpful. Even if the BM is examined, the diagnosis often remains uncertain in these patients. In addition, more than one potential cause of cytopenia may be present, especially in the elderly. A myelodysplastic syndrome (MDS) or another BM disorder, but also an overt autoimmune or other inflammatory disease, may develop during follow-up in these patients. A key problem is that in an early phase of MDS, most laboratory and clinical signs are “nonspecific.” One of the very few reliable peripheral blood parameters distinguishing between an early or “pre-phase” of MDS and most other causes of a mild cytopenia are the numbers of circulating colony-forming progenitor cells. In addition, flow cytometric and molecular investigations may sometimes assist in the delineation between clonal and reactive conditions underlying mild cytopenias. This review provides an overview of diagnostic approaches and algorithms for patients with mild unexplained cytopenia(s).

Low blood counts: immune mediated, idiopathic, or myelodysplasia.

Traditionally, cytopenias are classified as deficiency mediated, immune mediated, BM failure induced, renal, or idiopathic, with the latter including the so-called idiopathic cytopenias of undetermined significance (ICUS). Clinical findings, symptoms, blood counts, BM findings, and other laboratory parameters are usually sufficient to reveal the type and cause of a marked cytopenia. However, in patients with chronic mild cytopenia, it may be a challenge for the physician to establish a correct diagnosis. In such patients, laboratory features and findings often reflect a diagnostic interface, so that criteria that are otherwise robust may hardly be applicable or are not helpful. Even if the BM is examined, the diagnosis often remains uncertain in these patients. In addition, more than one potential cause of cytopenia may be present, especially in the elderly. A myelodysplastic syndrome (MDS) or another BM disorder, but also an overt autoimmune or other inflammatory disease, may develop during follow-up in these patients. A key problem is that in an early phase of MDS, most laboratory and clinical signs are "nonspecific." One of the very few reliable peripheral blood parameters distinguishing between an early or "pre-phase" of MDS and most other causes of a mild cytopenia are the numbers of circulating colony-forming progenitor cells. In addition, flow cytometric and molecular investigations may sometimes assist in the delineation between clonal and reactive conditions underlying mild cytopenias. This review provides an overview of diagnostic approaches and algorithms for patients with mild unexplained cytopenia(s).

Dysplasia Has A Differential Diagnosis: Distinguishing Genuine Myelodysplastic Syndromes (MDS) From Mimics, Imitators, Copycats and Impostors

Just as a pawnshop owner who is unable to distinguish a genuine Rolex™ watch from a cheap knockoff courts financial ruin, the physician who fails to discriminate between authentic myelodysplastic syndromes (MDS) and conditions resembling MDS risks misinforming or harming patients. This review summarizes minimal criteria for diagnosing MDS and discusses common diagnostic challenges. MDS needs to be separated from numerous neoplastic and non-clonal hematologic disorders that can mimic MDS, including other myeloid neoplasms, nutritional deficiencies, toxin exposures, aplastic anemia, and inherited disorders (e.g., congenital sideroblastic anemia). Some distinctions are more critical therapeutically than others; e.g., recognizing B12 deficiency is more important than parsing high-risk MDS from erythroleukemia. Diagnostically ambiguous cases may be assigned holding-pattern terms, "idiopathic cytopenia(s) of undetermined significance" (ICUS) or "idiopathic dysplasia of undetermined significance" (IDUS), while awaiting clarifying information or further clinical developments. In the future, advances in molecular pathology will improve diagnostic accuracy, especially in morphologically non-descript cases.

Déficits immunitaires primitifs et cytopénies auto-immunes de l’adulte

Although primary immunodeficiencies (PID) are typically marked by increased susceptibility to infections, autoimmune manifestations have increasingly been recognized as an important component of several forms of PID. Here, we discuss two forms of PID in which autoimmune cytopenias are particularly common and may be the first manifestation of the disease in adults: autoimmune lymphoproliferative syndrome (ALPS) and common variable immunodeficiency (CVID). Approximately one fifth of patients with CVID develop autoimmune diseases, and immune thrombocytopenic purpura (ITP) and autoimmune hemolytic anemia (AHA) are the most common. Since autoimmune cytopenias frequently precede the diagnosis of CVID, testing for immunoglobulin levels should be performed in patients diagnosed with AITP and AHA. Patients with CVID in association with autoimmune cytopenias have a “particular phenotype” with lower susceptibility to infection and higher susceptibility to autoimmune manifestations and, for patients with AHA, a more frequent development of splenomegaly and lymphoma. Corticosteroids and high doses of intravenous immunoglobulins (IVIg) seem to have the same efficacy as in idiopathic AITP and AHA. Splenectomy and rituximab are as effective as in idiopathic autoimmune cytopenias but are associated with an increased risk of severe infection and should, in our opinion, be considered only for those rare patients with “refractory diseases”. The course and outcome of autoimmune cytopenias is not affected by supportive IVIg therapy. Autoimmune destruction of blood cells affects over 70% of ALPS patients. The median age of first presentation is 24months of age, but with increasing awareness of this condition, adults with autoimmune cytopenias are now being diagnosed more frequently. Testing for ALPS should therefore be considered in young adults with unexplained Evan's syndrome. Patients usually respond to immunosuppressive medications, including corticosteroids. Unlike many patients with idiopathic autoimmune cytopenias, the cytopenias in patients with ALPS typically do not respond to IVIg. After corticosteroids, the immunosuppressive drug that is the most studied in ALPS patients is mycophenolate mofetyl. Rituximab and splenectomy are relatively contraindicated in ALPS because of an increase risk of severe infection and should be reserved for patients who fail all other therapies.

Expression of the CAMPATH-1 Antigen (CD52) on CD34+/CD38- Progenitor Cells in Patients with 5q- MDS and in a Subset of AML

Abstract 1728The target antigen CAMPATH-1 (CD52) is widely expressed in various hematopoietic lineages inlcuding lymphocytes, basophils, and blood monocytes. The anti-CD52 antibody Alemtuzumab is used successfully to treat patients with chemotherapy-refractory chronic lymphocytic leukemia. Based on its strong immunosuppressive effects, Alemtuzumab has also been considered for patients with aplastic anemia and hypoplastic myelodysplastic syndromes (MDS). Indeed, more recently, Alemtuzumab was found to induce major hematologic responses in a group of patients with MDS. Although the immunosuppressive effect was considered to play a role, the exact mechanisms underlying this drug effect remained speculative. In the current study, we asked whether CD34+ bone marrow (BM) progenitor cells in MDS and acute myeloid leukemia (AML) express the CAMPATH-1 antigen. Twelve patients with MDS (5 females, 7 males; median age: 70 years), 25 patients with AML (16 females, 9 males; median age: 62 years), and 34 control cases (normal reactive BM, n=12; idiopathic cytopenia of unknown significance, n=11; chronic myeloid leukemia, CML, n=4; chronic myelomonocytic leukemia, CMML, n=3; JAK2 V617F+ myeloproliferative neoplasms, MPN, n=4) were examined. Surface expression of CD52 on CD34+/CD38+ and CD34+/CD38- BM progenitor cells was analyzed by monoclonal antibodies and multicolor flow cytometry. In the group of MDS, CD52 was detectable on CD34+/CD38- stem cells in 3/4 patients with isolated 5q-. In most of the other MDS patients, CD52 was weakly expressed or not detectable on CD34+/CD38- cells. In AML, CD34+/CD38- cells displayed CD52 in 12/25 patients, namely 3 with complex karyotype including 5q-, 2 with inv(3), one with t(8;21), one with inv(16), one with del13q, one with trisomy 8, one with monosomy 7, and 2 with normal karyotype. Expression of CD52 mRNA in CD34+/CD38- AML stem cells was confirmed by qPCR in all patients tested (n=14). In addition, a good correlation was found between surface CD52 expression and CD52 mRNA expression in AML progenitor fractions. In patients with normal hematopoiesis (n=12) or idiopathic cytopenia (n=11), CD34+/CD38- cells stained weakly positive or negative for CD52. Almost in all cases tested, blood monocytes and blood basophils stained positive for CD52. Together, our data suggest that the target antigen CAMPATH-1 (CD52) is expressed on primitive CD34+/CD38- progenitor cells in MDS, preferentially in 5q- patients, and in a subset of patients with AML. These observations may have clinical implications and explain recently described effects of Alemtuzumab in patients with MDS. Our data also suggest that Alemtuzumab may be an interesting targeted drug in patients with refractory or relapsed AML in whom neoplastic stem cells express the target antigen CD52. Disclosures:No relevant conflicts of interest to declare.

Autoimmune cytopenia in chronic lymphocytic leukaemia: diagnosis and treatment

Autoimmune cytopenia, especially autoimmune haemolytic anaemia (AIHA), appears in 5-10% of patients with chronic lymphocytic leukaemia (CLL). In these patients, the prognosis is not as poor as in those cases in which the cytopenia is due to a massive bone marrow infiltration by the disease, and their treatment requires special considerations. For these reasons, the diagnosis of autoimmune cytopenia should be entertained in any patient with CLL presenting with cytopenia. In patients with autoimmune cytopenia and CLL, treatment is as for idiopathic autoimmune cytopenia, with most patients responding to corticosteroids. For patients not responding to corticosteroids, splenectomy is a reasonable treatment choice. Monoclonal antibodies and thrombopoietin analogues have shown enough activity to support their use, especially within clinical studies, in selected cases not responding to corticosteroids and before splenectomy. In patients with resistant immune cytopenia, the most effective treatment is that of the underlying CLL. Fear of fludarabine-associated AIHA is no longer appropriate in the age of chemo-immunotherapy. Finally, prospective studies are required to better identify the optimal therapy for these patients.

126 Differences in patient characteristics between low-grade myelodysplastic syndromes and idiopathic cytopenia of uncertain significance

126 Differences in patient characteristics between low-grade myelodysplastic syndromes and idiopathic cytopenia of uncertain significance

Persistent Tn polyagglutination syndrome during febrile neutropenia: a case report and review of the literature

IntroductionTn polyagglutination syndrome is a rare disorder that has been reported on only a few occasions in the literature, and, to the best of our knowledge, never before in the context of febrile neutropenia.Case presentationWe report the case of a 26-year-old Caucasian woman who presented to our emergency department complaining of a persistent fever over the previous three days. She had a history of long-standing refractory pancytopenia with multi-lineage dysplasia and severe neutropenia, but she had rarely experienced infection. The results of a physical examination and multiple laboratory tests were unremarkable. While investigating the possible causes of the refractory, long-standing pancytopenia, the possibility of a polyagglutinable state was suggested. Blood samples were sent to the laboratory for an analysis of mixed-field seed lectin agglutination assay. A serum lectin panel confirmed the final diagnosis of Tn-activation.ConclusionsWe should include Tn-activation in our differential whenever we encounter cases of refractory long-standing idiopathic cytopenias and inconclusive bone marrow results displaying multi-lineage dysplasia. Novel genetic techniques have recently revealed the interesting pathophysiology of this phenomenon. The recognition and inclusion of Tn polyagglutination syndrome in our differential diagnoses has important clinical implications, given its main associated features, such as severe thrombocytopenia and neutropenia, which are usually linked to a benign clinical course and prognosis. Increased awareness of the polyagglutinable disorders will potentially decrease the need for invasive and costly medical interventions and also raises the need for monitoring of this specific sub-set of patients. In addition, the study of the expression and implications of Tn, and other similar antigens, offers a fascinating perspective for the study of its role in the diagnosis, prognosis and immunotherapy of solid tumors and hematological malignancies. The infrequency with which Tn polyagglutination syndrome is encountered, its clinical features and its pathophysiology make it a formidable diagnostic challenge.

Using the Genetics of the Autoimmune Lymphoproliferative Syndrome to Guide Therapy

AbstractAbstract SCI-7Autoimmune Lymphoproliferative Syndrome (ALPS) is a disorder of abnormal lymphocyte survival caused by defective Fas-mediated apoptosis. Patients with ALPS may present with lymphoproliferation (lymphadenopathy and hepatosplenomegaly), autoimmune disease (most commonly autoimmune cytopenias), and secondary malignancies (typically EBER+ non-Hodgkin lymphoma). Eighty percent of ALPS patients have an identifiable genetic mutation in FAS (TNFRSF6), FASL (TNFSF6), or CASP10. These mutations can be germline or somatic with localization to the double negative T cell (DNT) compartment. DNTs (cell phenotype TCRα/β+, CD3+, CD4−, CD8−) are an atypical T cell population found in elevated quantities in peripheral blood and lymphoid tissue in ALPS patients. The diagnostic criteria for ALPS were modified in 2010 based on the results of an international consensus conference and include meeting a constellation of clinical findings, elevated DNTs, abnormal biomarkers (elevated vitamin B12, IL-10, and sFasL), in vitro evidence of defective Fas-mediated apoptosis, and mutations (somatic or germline) in Fas pathway genes. Patients with idiopathic autoimmune cytopenia syndromes (ITP, AIHA, and Evans Syndrome) and rheumatologic conditions (SLE) may have similar clinical presentations as ALPS. Our group demonstrated that approximately 45% of children diagnosed with Evans syndrome may in fact have a forme fruste of ALPS as confirmed by genetic and functional testing. Diagnosing ALPS with genetic confirmation is extremely important, because patients with idiopathic immune cytopenias should receive different treatment than ALPS patients. While first line therapy for both uses IVIgG and corticosteroids, two second-line treatments routinely used for refractory and/or chronic idiopathic autoimmune cytopenias are relatively contradicted in ALPS patients. Splenectomy has been associated with pneumococcal sepsis despite appropriate vaccination and antibiotic prophylaxis in ALPS patients. It is hypothesized that ALPS patients have increased difficulty fighting encapsulated organisms and splenectomy should be avoided. Rituximab (anti-CD20 monoclonal antibody) has been shown to cause profound and potentially life-long hypogammaglobulinemia similar to common variable immunodeficiency when used in ALPS patients and should also be avoided. In contrast, other agents used less commonly in idiopathic autoimmune cytopenias have demonstrated remarkable success in ALPS. Mycophenolate mofetil (MMF) improves autoimmune cytopenias in some refractory ALPS patients and is often used as second line treatment. Recently, we demonstrated that the mTOR inhibitor sirolimus (rapamycin) is extremely effective in ALPS both in preclinical models and in children. We have found complete responses in most patients treated with sirolimus to date. Unlike other agents, we found that sirolimus improved both autoimmune disease and lymphoproliferation, as well as specifically targeting the abnormal DNTs. No other agent, including corticosteroids, has been demonstrated to eliminate DNTs. Our preliminary data suggest that the DNTs have intrinsic abnormalities in mTOR signaling, potentially driving the autoimmune disease; and, therefore, we have a possible biologic explanation for the profound effects. Ongoing work will determine if the mTOR signaling abnormalities are specific to FAS-mutant ALPS or whether they are also found in other genetic ALPS variants that result in abnormal Fas-mediated apoptosis. Disclosures:Off Label Use: Sirolimus and mycophenolate mofetil are medications used to treat refractory autoimmune disease in patients with ALPS.

Distinguishing myelodysplastic syndromes (MDS) from idiopathic cytopenia of undetermined significance (ICUS): HUMARA unravels clonality in a subgroup of patients

BackgroundPatients not fulfilling minimal criteria for myelodysplastic syndromes (MDS) but presenting with persisting cytopenia(s) not attributable to a haematological or non-haematological disease are defined as ‘idiopathic cytopenia of undetermined significance’ (ICUS). Design and methodsWe retrospectively analysed 67 of 3504 patients from our MDS Registry fulfilling the criteria for ICUS. Furthermore, we used the human androgen receptor gene-based assay (HUMARA) to look for clonality. ResultsOf all 67 patients, 66% had unilineage, 18% bilineage and 12% trilineage cytopenias. The majority of patients (67%) presented with anaemia. Median overall survival was 44 months (range: 1–199 months). In the entire group, eight patients (12%) developed acute myeloid leukaemia (AML). Of the 23 patients eligible for HUMARA, 17 had non-clonal X-chromosome inactivation patterns, while 6 patients showed clonal patterns. Two of these six patients developed AML indicating that a clonal stem cell disorder was the reason for the anteceding cytopenia, while there was no AML observed among the 17 patients with non-clonal patterns (P = 0.013). ConclusionsSince some of the ICUS patients had a clonal bone marrow disease when presenting with cytopenia(s) and 8 of 67 patients with ICUS later developed AML, we recommend to follow these patients thoroughly. As demonstrated here, HUMARA can facilitate the discrimination between ICUS and a ‘manifest’ MDS.

Correspondence: PNH‐phenotype cells in patients with idiopathic cytopenia of undetermined significance (ICUS) with megakaryocytic hypoplasia and thrombocytopenia

correspondence: PNH‐phenotype cells in patients with idiopathic cytopenia of undetermined significance (ICUS) with megakaryocytic hypoplasia and thrombocytopenia

Myelodysplastic Syndrome Mimicking Idiopathic Thrombocytopenic Purpura

In patients with isolated thrombocytopenia, but without significant dysplasia, diagnosis of idiopathic thrombocytopenic purpura (ITP) rather than myelodysplastic syndrome (MDS) may be taken into account. It is important to make an accurate diagnosis because different treatments are used for ITP and MDS. The purpose of this study was to investigate the clinical and hematologic features of patients who were initially diagnosed as ITP but had cytogenetic abnormalities. We retrospectively reviewed cytogenetic studies of 100 patients who were diagnosed as ITP from 2004 to 2009 at Mokdong Hospital of Ewha Womans University based on clinical features and hematologic studies. Bone marrow pathology was re-evaluated based on 2008 WHO classification. Cytogenetic analysis was performed by 24-48 hr culture of bone marrow aspirates without using mitogens and 20 metaphases were analyzed. Of the 100 patients diagnosed as ITP initially, three patients (3%) had cytogenetic abnormalities. They had no thrombocytopenia-related symptoms and thrombocytopenia was found accidentally. The numbers of megakaryocytes in bone marrow were increased and dysplasia was not found in megakaryocyte, erythroid, and myeloid cell lineages. The proportion of blasts was within normal limits. Clonal chromosomal abnormalities found were der(1;7)(q10;p10), add(9)(q12), or t(7;11)(p22;q12). Presumptive diagnosis of MDS or diagnosis of idiopathic cytopenia of undetermined significance (ICUS) was made according to 2008 WHO classification. During the follow up, disease progression was not found. In patients with suspected ITP, cytogenetic analysis should be done. If specific clonal chromosomal abnormality is found, presumptive diagnosis of MDS has to be considered and close follow up is needed.

CD38 Expression On CD34+ Cells as a Single Flow Cytometric Parameter to Distinguish Myelodysplastic Syndromes (MDS) From Non-Clonal Cytopenias.

Abstract 2783Poster Board II-759Myelodysplastic syndromes are a heterogeneous group of bone marrow (BM) disorders characterised by clonal proliferation. The diagnosis of MDS can be challenging, especially in cases with minimal dysplastic changes by morphology and without characteristic karyotypic abnormalities. Recent investigations show that multi parameter analysis of BM samples of MDS patients by flow cytometry (FCM) might be of value in the diagnosis of MDS and for discriminating MDS from other disease entities. Detection of immunophenotypic abnormalities in the immature and the maturing myelomonocytic compartment is even included as a co-criterion in the minimal diagnostic criteria for MDS (Valent et al., Leuk Res 2009,31:727–36). Integration of FCM as a diagnostic tool in MDS requires a simple method with high sensitivity and specificity with low inter laboratory variation. Recently, reduced CD38 expression was demonstrated to discriminate between MDS and other disease entities (Goardon et al., Haematologica 2009, 94:1160–63).To validate the value of CD38 in the diagnosis of MDS, we analysed BM samples of 27 MDS patients (refractory anemia n=4; refractory anemia with multi lineage dysplasia n=15; refractory anemia with excess blasts [RAEB]-1 n=4 and RAEB-2 n=4), age-matched healthy volunteers (n=16) and pathologic controls (n=39). The pathologic control group consisted of aplastic anemia (n=3), iron deficiency (n=6), Multiple Myeloma (n=8), B-cell non-Hodgkin lymphoma (n=6) and autoimmune thrombocytopenia (n=3) patients. We found that CD38 RMFI on CD34+ cells was significantly decreased in MDS with less than 5% blasts (mean±SD: 216.5±95.4) as compared to pathologic controls (mean±SD: 377.2±246.1, P=0.01) and healthy volunteers (mean±SD: 322.8±138.1, P=0.02). In RAEB-1/-2, CD38 RMFI (mean±SD: 111.3±74.9, P=0.001) was even more decreased in comparison with both pathologic controls and healthy volunteers. Expression of CD38 on CD34+ cells is heterogeneous and the most immature cells or hematopoietic stem cells are considered to be negative for CD38 expression. By using the median fluorescence intensity (RMedFI), the skewed distribution of CD38 expression on CD34+ cells is taken into account. In our cohort, RMedFI is significantly decreased in MDS with <5% blasts (mean±SD: 368.1±210.3, P=0.03) and MDS RAEB -1/-2 (mean±SD: 139.7±108.5, P<0.001) as compared to pathologic controls (mean±SD: 521.6±314.2). However, no significant differences were observed between RMedFI of CD38 of MDS with less than 5% blasts and healthy volunteers. In conclusion, we show that CD38 expression is reduced in CD34+ cells of MDS patients and might be of value in the diagnosis of MDS. However, there is considerable overlap in CD38 expression between the MDS with less than 5% blasts group and pathologic controls group and healthy volunteers group. Differentiation of MDS from other disease entities by FCM is based on an accumulation of aberrancies rather than a single aberrancy which might reflect the degree of deviation from normal. The number of aberrancies in the myelomonocytic and blast compartment can be translated by a flow cytometric scoring system into a flow score (Wells et al., Blood, 2003,102:394–403, van de Loosdrecht et al., Blood, 2008,111:1067–77). A flow score above 3 is suggestive for MDS. The clinical impact of CD38 expression as a single flow cytometric parameter or as part of a multi parameter analysis requires validation with emphasis on inconclusive cases such as idiopathic cytopenia of unknown significance and idiopathic dysplasia of unknown significance. Flow cytometry in MDS is highly promising and prospective studies are warranted. Disclosures:No relevant conflicts of interest to declare.