Clarence C.K. Lam

Prevalence and specificity of clinically significant red cell alloantibodies in Chinese women during pregnancy – a review of cases from 1997 to 2001

Summary.u2002 Guidelines for the prevention and management of red cell alloantibodies during pregnancy, related to anti‐D in particular, are well established in Caucasian populations. However, because of the racial difference of the blood group distribution, applicability to Chinese is unknown as a result of insufficient data on the prevalence and their outcome. In a retrospective review of 28u2003303 (21u2003327 Chinese) antenatal attendances from 1997 to 2001, 213 (0·79%) women were found to have a total of 230 irregular antibodies. About 137 (0·64%) were ethnic Chinese, and a total of 160 irregular antibodies were identified in their blood samples. About 58 of these Chinese women (0·27%) were found to have 66 clinically significant antibodies. There was only one case of anti‐D detected in an Rh(D)‐negative subject. Our study shows the overall prevalence of clinically significant antibodies in Chinese women, which was not different from that of the Western population. However, the specificities of the antibodies differ with the commonest antibodies encountered; these being anti‐Mi (57·6%), anti‐E (19·7%), anti‐S (10·6%) and anti‐c (7·6%). Neonatal jaundice was observed in 37 babies and 10 of them required phototherapy. The findings support the previous recommendation that routine antenatal antibody screening for Chinese women may not be worthwhile except in Rh(D)‐negative subjects or those with an antecedent history of haemolytic disease of the newborn (HDN). The relative high incidence of anti‐Mi in the present study and the local population, in general, may warrant a large‐scale prospective study of pregnancy outcome in these subjects, especially in the light of the previous case reports of HDN because of anti‐Mi.

Focal segmental glomerulosclerosis and mesangial sclerosis associated with myeloproliferative disorders

The myeloproliferative disorders (MPDs) are clonal disorders of the hematopoietic stem cell and classified as polycythemia vera (PV), essential thrombocythemia (ET), or agnogenic myeloid metaplasia (AMM), depending on the main hematopoietic lineage involved. Primary renal parenchymal lesions are not commonly reported in these cases. We conducted a retrospective analysis of 138 consecutive patients with MPD to determine the frequency of renal parenchymal complications. Five patients (3.6%) (two PV, two ET, one AMM) were found to have focal segmental glomerulosclerosis (FSGS) and diffuse mesangial sclerosis, presenting as proteinuria in all the cases and progressing to chronic renal failure in two cases. A possible common risk factor was a high platelet count, because abnormal platelet activation in MPD has been shown to contribute to the development of glomerulosclerosis. The pathophysiologic basis of our observations and the implications in management of MPD patients remain to be studied.

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.

Tetraploid acute promyelocytic leukemia with large bizarre blast cell morphology

We describe a case of atypical acute promyelocytic leukemia (APL) with a tetraploid clone and multiple karyotypic abnormalities in addition to the translocation (15;17)(q22;q21). Microscopically, the leukemic cells were highly heterogeneous in morphology and granularity, being bizarre and large in size compared with classical APL blasts. The patient responded to treatment with chemotherapy and all-trans-retinoic acid, at diagnosis and at relapse 10 months later. He is currently in clinical and molecular remission, 3 years after initial diagnosis. Tetraploidy in association with large and bizarre blasts has not been previously reported in APL. Although tetraploidy and complex karyotypic aberrations confer a poor prognosis in other types of acute myeloid leukemia, in the presence of t(15;17) they did not appear to affect the prognosis, inasmuch as the clinical features and treatment outcome in our case followed those of APL in general.

Plasmablastic transformation of multiple myeloma

We describe morphological, immunophenotypic, and cytogenetic characterization of a case of multiple myeloma (MM) that showed plasmablastic transformation at the terminal phase with a picture resembling acute leukemia. The plasmablasts expressed monotypic cytoplasmic immunoglobulin together with myeloid and megakaryocytic markers at disease transformation. Conventional cytogenetic study of bone marrow cells showed coexistence of hypodiploid and hyperdiploid cells, with the former being the predominant clone as evidenced by an interphase fluorescence in situ hybridization study. The clinical course in our case shows that plasmablastic transformation should be considered in the differential diagnoses of disease progression in MM. Whether de novo plasmablastic myeloma and plasmablastic transformation can be distinguished as a progression from underlying MM merits further investigation, especially in terms of biologic features and relevance to prognosis.

Diffuse Osteosclerosis Complicating Hairy Cell Leukemia

A 67-year-old man presented with mild pancytopenia 3 years ago, for which no specific treatment was given. Progressive anemia necessitated a bone marrow examination 2 years later. Aspiration yielded a dry tap, and a trephine biopsy showed marked osteosclerosis with myelofibrosis. On referral, physical examination was normal. Blood counts showed hemoglobin of 8.3 g/dL, WBC count of 2.8 10/L (neutrophils, 1.8 10/L; lymphocytes, 0.9 10/L; monocytes, 0.08 10/L), and platelet count of 81 10/L. No abnormal cells were discernable on the blood film. Dual-energy x-ray absorptiometry showed massively increased bone mass density (BMD), particularly over the axial skeleton and long bones (Fig 1A, arrows). The measured BMDs at different regions were as follows: lumbar spine, 2.28 g/cm (11 standard deviations [SDs] above the mean for young adults); femur, 1.95 g/cm (eight SDs above mean); and total body, 1.61 g/cm (5.6 SDs above mean; Fig 1B). A positron emission tomography– computed tomography confirmed the osteosclerosis, but no solid tumors were detectable. Bone marrow biopsy was repeated. Severe osteosclerosis (Fig 2A, arrows, hematoxylin and eosin staining) was present, along with a dense infiltrate of abnormal lymphoid cells, showing a typical spaced appearance, with pale to clear areas surrounding the nuclei (Fig 2A, insert, red arrows). Severe reticulin fibrosis (Fig 2B, silver staining) was also present. Immunohistochemical analysis showed that the lymphoid cells were positive for CD20 and acid phosphatase isoenzyme 5 (tartrate resistant; Fig 2C, immunoperoxidase staining). A review of the peripheral-blood buffy coat showed rare abnormal lymphoid cells with hairy projections (Fig 2D, arrow, Wright-Giemsa staining). The overall findings were consistent with hairy cell leukemia (HCL). Serum level of the osteoclastogenesis inhibitory factor osteoprotegerin (assayed by enzyme-linked immunosorbent assay; Biomedica Gruppe, Vienna, Austria) was grossly elevated at 11.5 pmol/L (normal adult male, 0.55 to 2.35 pmol/L). The patient received one course of subcutaneous 2-chlorodeoxyadenosine (0.14 mg/kg/d 5). Blood counts gradually normalized. A marrow trephine biopsy 4 months later showed persistence of osteosclerosis, but no abnormal lymphoid cells could be found. The BMD had remained unchanged (total body, 1.68 g/cm), which was an expected result because bone turnover typically takes much longer. Except for unusual cases of late-onset osteopetrosis, diffuse osteosclerosis in adults is almost invariably associated with underlying neoplasms. Metastases from prostate and breast cancer and advanced primary myelofibrosis are important causes. Osteosclerosis

Hepatitis C virus infection in adult chinese hemophilia patients negative for the human immunodeficiency virus: Treatment results with interferon and ribavirin

Hepatitis C virus (HCV) eradication in hemophilia patients depends on viral and patient factors. We report the treatment results with interferon α (5 megaunits, 3 times per week) and ribavirin (1 g daily) for 1 year in 17 Chinese patients who were negative for the human immunodeficiency virus. The HCV genotype consisted of a mixture of Western (genotypes 1, 2, and 3) and Chinese (genotypes 1 and 6) patterns. Quasi species were common (29%). Seven patients (41%) stopped treatment because of complications. Sustained HCV eradication was achieved until the end of treatment or for 24 months in 7 of 17 patients, respectively. A sustained response occurred in 50% of the patients completing treatment and occurred only in patients with genotypes 1, 3, and 6 but not with quasi species.

Can morphological assessment limit the use of specific genetic testing to exclude chronic myeloid leukaemia

Between January 2004 and June 2006, a total of 66 unselected peripheral blood or marrow aspirate samples from patients with evidence of myeloproliferation were received by our cytogenetics and molecular laboratory for BCR/ABL detection to exclude chronic myeloid leukaemia (CML) [morphological diagnosis: polycythaemia vera (PV) in 10, essential thrombocythaemia (ET) in 22, chronic idiopathic myelofibrosis (CIMF) in 12, hypereosinophilic syndrome in one, chronic myeloproliferative diseases (CMPD), unspecified in 20 and myelodysplastic/myeloproliferative diseases (MDS/MPD) in one]. Significant peripheral basophilia (absolute basophil count >1 · 10/l) was only seen in four of 57 patients with available white cell differential counts (two with CMPD, one with PV and one with CIMF), and none of them had a count >2 · 10/l. Marrow morphology was examined by haematopathologists before genetic testing. In 60 patients with available marrow aspirate specimen, proliferation of small and hypolobulated megakaryocytes typical of CML were found and documented in only four cases (one each of CMPD, unspecified, PV, ET and MDS/MPD). As none of these 66 patients received a morphological diagnosis of CML from initial peripheral blood and/or marrow examination, according to our protocol we did not perform conventional cytogenetics but employed dual-colour dual-fusion fluorescence in-situ hybridisation (D-FISH; Vysis, Downers Grove, IL, USA) for exclusion of BCR/ABL fusion in this setting (Wan et al, 2003). Three hundred nuclei were scored in each case. Test sensitivity was 0Æ8%. BCR/ABL fusion was not detected in any of the 66 cases. A further 14 cases with a pretest diagnosis of reactive cytosis were analysed in the same period by D-FISH and all showed a negative result. During this period, 72 cases with a morphological diagnosis of CML were analysed by conventional cytogenetics in our laboratory (plus FISH in nine cases that showed no growth or a normal karyotype). Of these, 51 cases were previously untreated and had blood counts and bone marrow examination results reported before karyotyping. All 51 cases were documented to have proliferation of small and hypolobulated megakaryocytes in bone marrow and significant peripheral basophilia of >1 · 10/l (range 1Æ15–38Æ82 · 10/l, median 10Æ64 · 10/l; basophil count >2 · 10/l in 47 cases). The diagnosis was confirmed in 70 cases by the detection of t(9;22)(q34;q11.2) in 63 out of 72 cases examined or positive FISH fusion signals in seven out of nine cases examined. A review of the records during this period showed that a Ph chromosome was detected in 11 non-CML cases by conventional cytogenetics. None of them had a pretest diagnosis of CMPD (precursor lymphoblastic leukaemia in nine, acute myeloid leukaemia in two). Although one may argue that the present FISH technique with 0Æ8% test sensitivity may not be able to detect a very small BCR/ABL fusion-positive clone, this should not be relevant in our series as most patients were newly diagnosed and untreated. None of them had received imatinib, which could have reduced the clone size to this level. Our results show that cases lacking characteristic morphological features of CML are highly unlikely to be positive for BCR/ABL fusion. Careful morphological examination can therefore help to decide whether further genetic testing to exclude CML is indicated. The well-accepted, but not well-scrutinised, approach of screening all patients with CMPD for BCR/ABL fusion to exclude CML needs to be re-evaluated. Careful re-examination of those rarely reported cases of ‘PV-like’ or ‘ET-like’ CML for these highly sensitive morphological features is warranted. We propose that in patients with evidence of myeloproliferation but without significant peripheral blood basophilia and lacking characteristic small hypolobulated megakaryocytes on bone marrow examination, specific genetic tests performed solely for the purpose of excluding CML can safely be withheld, unless suggestive morphological features develop during monitoring. With this approach, laboratory resources can be utilised more cost-effectively.

Reemergence of JAK2 V617F clone heralds extramedullary leukemia relapse after BMT for transformed essential thrombocytosis.

Dear Editor, The novel finding of a V617F mutation in the JAK2 kinase molecule has revolutionized the disease classification of myeloproliferative disease (MPD) [1]. However, without specific JAK2 pathway antagonists, hydroxyurea (HU), interferon, and anagrelide remain the mainstay of treatment. Hemopoietic stem cell transplantation (HSCT), the only curative option, is reserved for cases with blastic transformation [2]. There are few reports on the use of the aberrant JAK2 mutation to monitor residual disease after HSCT for MPD [3]. The relative efficacy of JAK2 V617F polymerase chain reaction (PCR) detection versus conventional chimerism or morphology monitoring is unknown. A 52-year-old man suffered from essential thrombocytosis since 1990 [hemoglobin (Hb)=14.1 g/dl, white cell count (WCC)=26.9×10/l, platelet (Plt)=1,162×10/l] with hypercellular marrow and normal cytogenetics (Fig. 1a). He was treated with HU for 12 years but developed anemia (Hb=5.0 g/dl, WCC=9.1×10/l, Plt=147×10/l) and gross splenomegaly. A repeat marrow biopsy showed diffuse fibrosis. Splenectomy was performed, and he required regular transfusion. Two years later, he developed frank leukemia (Hb=9.3 g/dl, WCC=3.9×10/l, 22% blasts, Plt=60×10/l), and the cytogenetic study showed 47, XY, +der(8)t(1;8)(q21;p23) [3]. An allogeneic HSCT from his human leukocyte antigen (HLA)-identical brother was performed, and he engrafted with no graft versus host disease (GVHD). The marrow showed morphological remission and complete donor chimerism at one year (Hb= 8.9 g/dl, WCC=8.3×10/l, Plt=317×10/l). However, JAK2 aberration, undetectable early after HSCT, reappeared after one year (sensitivity, 1 in 10) [4]. At the 16-month follow-up, he developed progressive, tender knee swellings (Fig. 1b). A needle biopsy showed leukemic cells (Fig. 1c) with normal marrow and blood counts. Despite radiotherapy and the stopping of immunosuppressants, the patient proceeded to frank marrow relapse. This was accompanied by increasing intensity of the JAK2 mutation signal and loss of chimerism. He was treated with chemotherapy and further peripheral stem cells from the same donor but died of fulminant GVHD. The molecular detection of JAK2 mutation heralded extramedullary relapse in our case and was more sensitive than chimerism study and routine clinical and hematological monitoring in detecting disease. This is not unexpected given the sensitivity of PCR detection. It is uncertain if sensitivity is further increased in cases with homozygous mutations. However, it must be remembered that a negative result may not safeguard against leukemia relapse because JAK2 negative leukemic clones are present in transformed MPD [5]. Nevertheless, given the poor clinical outcome and high incidence of relapse for HSCT for transformed MPD, a positive PCR result may provide a window of opportunity for early use of donor lymphocyte infusion or chemotherapy for disease suppression before loss of chimerism. Ann Hematol (2007) 86:145–147 DOI 10.1007/s00277-006-0213-2