Chi-Chiu So

Nucleolated Variant of Mantle Cell Lymphoma With Leukemic Manifestations Mimicking Prolymphocytic Leukemia

Chronic lymphoproliferative disorders sometimes can be difficult to classify. We report 4 cases characterized by large cells with distinct central nucleoli, reminiscent of prolymphocytic leukemia, but shown on further workup to represent mantle cell lymphoma. At initial examination, the patients had generalized lymphadenopathy, splenomegaly, and a leukemic blood picture. The peripheral blood showed many large cells with round to slightly irregular nuclei, single central nucleoli, and a fair amount of pale cytoplasm. The picture was not typical of prolymphocytic leukemia because of the presence of generalized lymphadenopathy and the large size of the circulating abnormal cells. Immunophenotypic study showed that the large lymphoid cells were CD5+ CD23- mature B cells with overexpression of cyclin D1, and cytogenetic study demonstrated the translocation t(11;14)(q13;q32) in 3 patients. Lymph node biopsy confirmed a diagnosis of mantle cell lymphoma, pleomorphic variant, in all 4 patients. This study documents the existence of an unusual leukemic form of mantle cell lymphoma with prominent nucleoli; the clinicopathologic features that distinguish it from other chronic lymphoproliferative disorders are discussed.

A laboratory strategy for genotyping haemoglobin H disease in the Chinese

Background: The thalassaemias are the commonest blood disorders worldwide, with South East Asia and southern China as areas of high prevalence. Accurate diagnosis of these disorders helps in clinical management with improved outcome. Methods: The α-globin genotypes of 100 Chinese patients in Hong Kong with haemoglobin H (Hb H) disease were characterised. Single-tube multiplex gap-PCR was used to detect −−SEA, −α3.7 and −α4.2, while Hb CS, Hb QS and codon 30 (ΔGAG) were identified by single-tube multiplex amplification refractory mutation system (ARMS). Automated direct nucleotide sequencing of the amplified α2- and α1-globin genes was performed to characterise other non-deletional α-thalassaemia determinants. Results: In the 100 cases studied, 99 cases had −−SEA in combination with deletional α+-thalassaemia or non-deletional α-globin gene mutation involving the α2-globin gene. In 70 cases of the deletional form, 43 cases showed the genotype of (−−SEA/−α3.7) and 27 cases of (−−SEA/−α4.2). Three of the 27 cases of (−−SEA/−α4.2) were found to have Hb Q-Thailand linked in-cis with −α4.2. The remaining 30 cases were of non-deletional form with the following genotypes: 11 cases of (−−SEA/αHbCSα), 9 cases of (−−SEA/αHbQSα), 3 cases of (−−SEA/αcd30 (ΔGAG)α), 3 cases of (−−SEA/αcd31α), 2 cases of (−−SEA/αpoly-Aα), 1 case of (−−SEA/αHbWestmeadα) and 1 case of (−−non-SEA/αHbQSα). Conclusions: Based on two rapid diagnostic tests, multiplex gap-PCR and multiplex ARMS, more than 90% of the cases were genetically characterised. This laboratory strategy should be widely applicable for genetic diagnosis of α-thalassaemia.

A single-center cytogenetic study of 629 Chinese patients with de novo acute myeloid leukemia—evidence of major ethnic differences and a high prevalence of acute promyelocytic leukemia in Chinese patients

Cytogenetic information is important in the diagnosis, classification, and prognostication of acute myeloid leukemia (AML). Data obtained from multicenter treatment trials are well published. In this study, we contribute cytogenetic data from a large series of 629 Chinese patients with de novo AML that were karyotyped in a single laboratory. A higher prevalence of acute promyelocytic leukemia was observed when compared with non-Chinese series. The difference was most prominent in the younger age group. Abnormalities at chromosomal region 11q23 and inv(16) seemed uncommon. These ethnic differences may indicate underlying genetic susceptibility to AML development and/or environmental differences. More comprehensive data on AML in the elder population are needed to assess the role of cytogenetics in predicting prognosis and guiding treatment in this large subgroup of patients.

Analysis of MLL-Derived Transcripts in Infant Acute Monocytic Leukemia with a Complex Translocation (1;11;4)(q21;q23;p16)

It has been proposed, on the basis of cytogenetic studies and molecular analysis of MLL-derived transcripts in acute leukemia with 11q23 rearrangement, that only one fusion gene transcript present on the der(11) chromosome is critical for leukemogenesis. This view is challenged by a recent observation in a case of leukemia with a complex translocation that results in MLL being fused in-frame to two different partner genes. We investigated a case of infant monocytic leukemia with a complex translocation, (1;11;4)(q21;q23;p16). Molecular studies revealed MLL rearrangement by both fluorescence in situ hybridization and Southern blot analysis, and MLL/AF1q, but not the reciprocal message (i.e., AF1q/MLL), was amplified by polymerase chain reaction. Sequence analysis of MLL/AF1q revealed an in-frame fusion between MLL exon 6 and the breakpoint located six bases upstream of the ATG start site for AF1q. Our data suggest that only one form of MLL fusion gene is implicated in leukemogenesis in our case to t(1;11;4).

Valproate-Associated Dysmyelopoiesis in Elderly Patients

Sodium valproate is widely prescribed for patients with epilepsy and psychiatric disorders. Hematologic toxic effects have been largely described in pediatric patients, and dysmyelopoiesis is reported rarely. We describe 2 elderly patients with valproate-associated dysmyelopoiesis and postulate that this particular side effect may be much more common than currently recognized. A correct diagnosis is important for acute patient anagement and for prognostication.

Novel Point Mutation of the α2-Globin Gene (HBA2) and a Rare 2.4 kb Deletion of the α1-Globin Gene (HBA1), Identified in Two Chinese Patients with Hb H Disease

Abstract Two Chinese patients with mild and moderate Hb H disease were investigated for rare mutations on the α-globin genes (HBA1, HBA2) in addition to the – –SEA deletion. One patient was a 41-year old man with mild anemia (Hb 11.3 g/dL). Multiplex ligation-dependent probe amplification (MLPA) revealed a rare 2392 bp deletion involving the entire HBA1 gene. Mapping by gap-polymerase chain reaction (gap-PCR) defined the exact breakpoints of this deletion (HBA1: g36859_39252del2392) and confirmed its identity with a recently reported HBA1 deletion found in a Southern Chinese. The other patient was a 53-year old man with moderate anemia (Hb 9.5 g/dL). Automated direct nucleotide (nt) sequencing identified a novel single nt deletion at codon 40 (HBA2: c.123delG). This leads to a frameshift that modifies the C-terminal sequence to (40)Lys-Pro-Thr-Ser-Arg-Thr-Ser-Thr(47)COOH and the introduction of a stop codon TGA 23 nts downstream. These two cases demonstrate the power of MLPA and direct nt sequencing to detect and characterize rare and novel mutations. They also highlight the differential effect of HBA1 and HBA2 gene mutations on an α-thalassemia (α-thal) phenotype due to their different transcriptional activity.

Genetic basis of persistent red blood cell microcytosis in the Chinese unexplained by phenotypical testing

Aims Hypochromic microcytic anaemia is the hallmark phenotype of thalassaemia. Current phenotypical tests do not provide a diagnosis in a small proportion of patients with red blood cell microcytosis. We aim to evaluate the genetic basis of red cell microcytosis in these cases in our Chinese population. Methods We identified from a large cohort of 1684 unselected requests for thalassaemia testing 23 Chinese subjects who had unexplained microcytosis after phenotypical iron and haemoglobin studies. In 18 of these subjects with available DNA, extensive genotypical analysis of the α and β globin gene cluster was performed, including gap-PCR, multiplex amplification-refractory mutation system, Sanger sequencing and multiplex ligation-dependent probe amplification. Results Occult single and double α globin gene (HBA1, HBA2) deletions and α thalassaemic haemoglobinopathies (Haemoglobin Quong Sze, Haemoglobin Constant Spring) were the genetic basis for the microcytosis. Occult β globin gene (HBB) mutations and δ globin gene (HBD) abnormalities masking β thalassaemia are not seen. Conclusions A cost-effective genotyping approach for the detection of these occult globin gene mutations can be proposed. The identification of these mutations is important for making a diagnosis and for the provision of accurate genetic counselling. (This paper adds to our understanding of the genetic basis of red blood cell microcytosis in clinical practice, and it provides a cost-effective approach for genotyping in diagnostic laboratories).

May-Hegglin anomaly

A male baby was delivered prematurely at 27th week of gestation by emergency Caesarean section because of antepartum haemorrhage. He had severe hypospadias and bilateral inguinal hernias and also multiple complications of extreme immaturity. Peripheral blood examination showed a white cell count of 9Æ9 · 10 ⁄ l, a haemoglobin concentration of 13Æ4 g ⁄ dl and a platelet count of 48 · 10 ⁄ l. The platelets were giant and this was reflected by the grossly elevated mean platelet volume of 19Æ3 fl (normal 7–10 fl). A May–Grünwald–Giemsa-stained peripheral blood smear examination revealed the presence of blue intracytoplasmic inclusions in the neutrophils, eosinophils and monocytes (top). Ultrastructurally, these Döhle-like bodies were shown to contain ribosomes and 10 nm filaments running along the long axis (bottom). These features are in contrast to the Döhle bodies found in neutrophils of patients with sepsis, which are composed of parallel strands of rough endoplasmic reticulum. May–Hegglin anomaly is an autosomal dominant disease characterized by macrothrombocytopenia and the presence of Döhle-like bodies in the white cells. It is classically an isolated hereditary disorder, but patients with concomitant congenital abnormalities have also been reported. A candidate gene, non-muscle myosin heavy chain A, on the long arm of chromosome 22 has been implicated.

Hb KODAIRA II: A HIGH OXYGEN AFFINITY VARIANT WITH A NOVEL MUTATION IN THEβ-GLOBIN GENE AND PHENOTYPIC IDENTITY TO Hb KODAIRA

A 35-year-old lady with a history of good health was diagnosed as having impaired glucose tolerance during pregnancy. A hemoglobin (Hb) variant was incidentally detected when her blood was assayed for Hb A1c by automatic cation exchange high performance liquid chromatography (HPLC). Peripheral blood examination showed mild polycythemia: Hb 15.5 g=dL (normal 11.7–14.9 g=dL), RBC 5.57610=L (normal 3.9–5.0610=L), PCV 0.46 L=L (normal 0.35– 0.45 L=L), MCV 82.7 fL (normal 82–97 fL), MCH 27.7 pg (normal 27–33 pg) and MCHC 33.5 g=dL (normal 32–35 g=dL), with normal red cell morphology. Hb analysis using HPLC showed 45.8% Hb A, 2.7% Hb A2 (normal 1.5–3.5%) and a slightly increased Hb F value of 1.6% (normal <1%) which was probably related to her pregnant state. The rest (49.9%) was made up of a Hb variant. The variant co-migrated with Hb A in cellulose acetate electrophoresis at pH 8.3, but was separable from the latter at pH 6.0 (Fig. 1). Globin chain electrophoresis at pH 8.8 showed that it was probably a b chain variant (data not shown). The raised Hb level, normal red cell morphology and absence of clinical symptoms of anemia were suggestive of a Hb variant with high oxygen affinity. DNA sequencing of the b-globin gene revealed that the patient was heterozygous

The significance of dyserythropoiesis

A diagnosis of reactive haemophagocytic lymphohistiocytosis was made in a 10-year-old girl whose only notable past history was of asthma. She presented with fever, splenomegaly, hypertriglyceridaemia, hypofibrinogenaemia, hyperferritinaemia and pancytopenia. The nadir haemoglobin concentration (Hb) was 68 g/l, white blood cell (WBC) count 1 59 9 10/l and platelet count 119 9 10/l. A diagnostic bone marrow study revealed only erythroid hypoplasia. Haemophagocytic activity was not prominent in the marrow. No dysplastic features were noted. She was treated with etoposide, dexamethasone, ciclosporin and intravenous immunoglobulin. The peripheral blood count showed a good response. The Hb rose to 100 g/l and WBC and platelet counts normalized. A reassessment bone marrow aspiration was performed 2 months after diagnosis and revealed marked erythroid hyperplasia. Occasional frankly dysplastic erythroblasts were found, which were giant with prominent nuclear abnormalities (images). No dysplastic features were seen in the granulocytic or megakaryocytic series. The most recent dose of etoposide had been given 6 weeks previously and the patient was only on a low dose of oral steroid at the time of reassessment. The use of isolated dyserythropoiesis as a criterion for the diagnosis of myelodysplastic syndrome warrants caution for several reasons. Most importantly, dyserythropoietic features are commonly observed in stress erythropoiesis associated with rapid erythroid expansion, and also in aplastic anaemia. Of the three haemopoietic lineages, red cells most readily develop secondary dysplastic changes, presumably due to the intense proliferative drive to erythropoiesis. In addition, spurious dysplastic changes are often detected when bone marrow is stored for more than a few hours in anticoagulant. Furthermore, apart from the presence of ring sideroblasts, which can be objectively assessed, the interobserver concordance for other dyserythropoietic features, such as nuclear irregularity, megaloblastoid maturation and karyorrhexis, is poor. This patient demonstrates the marked cytological abnormalities that are sometimes observed in reactive conditions.