Edmond Shiu Kwan Ma

Immunorestitution disease involving the innate and adaptive response

Immunorestitution disease (IRD) is defined as an acute symptomatic or paradoxical deterioration of a (presumably) preexisting infection that is temporally related to the recovery of the immune system. We report the temporal sequence of events that led to IRD caused by Pneumocystis carinii and Aspergillus terreus in 2 human immunodeficiency virus (HIV)-negative patients soon after the recovery of adaptive and innate immunity, respectively, and we review episodes noted in the English-language literature that fit the definition of IRD (109 episodes in 107 patients). The median time from the recovery of neutrophil counts or termination of steroid therapy to the development of IRD was 8 days in cases of pulmonary aspergillosis (23 episodes) and hepatosplenic candidiasis (8) and 21 days for viral diseases such as hepatitis B (24) and viral pneumonitis (6). For IRD due to mycobacteriosis (27 episodes) and cryptococcosis (4) in HIV-positive patients, the median interval between the initiation of highly active antiretroviral therapy (HAART) and the onset of IRD was 11 days; for viral infections, including those due to cytomegalovirus (14), hepatitis B virus (1), and hepatitis C virus (2), the median interval was 42 days. As an emerging clinical entity, IRD merits further study to optimize treatment of immunosuppressed patients.

Single-Tube Multiplex-PCR Screen for Anti-3.7 and Anti-4.2 α-Globin Gene Triplications

The coexistence of α-globin gene triplication (ααα) is an important modulator of the severity of β-thalassemia trait or β-thalassemia intermedia, exacerbating the phenotypic severity of β-thalassemia by causing more globin chain imbalance (1)(2). Typically, the inheritance of a single β-thalassemia allele is associated with mild anemia and hypochromic microcytic red cells. Compared with simple β-heterozygotes, co-inheritance of triplicated or quadruplicated α-globin genes in β-heterozygotes often leads to more significant anemia, splenomegaly, more pronounced red cell abnormalities, the presence of circulating normoblasts, higher hemoglobin F concentrations, and even the presence of inclusion bodies in erythroblasts (3)(4). Because the α- and β-globin gene clusters are physically unlinked and segregate independently, β-thalassemia carriers who also carry triplicated or quadruplicated α-globin genes have a 25% risk of having a similarly affected offspring, although their partners may be entirely normal.nnTriplicated α-globin genes appear to be ubiquitous and have been found in most populations (2). They result from misalignment and unequal crossover between the homologous X-, Y-, and Z-box segments of the α-globin gene cluster during meiosis (Fig. 1A⇓ ). Generally, two types of triplicated alleles can be generated from an unequal crossover, αααanti3.7 and αααanti4.2. If the crossover occurs between the homologous Z2 and Z1 boxes, also referred to as a “rightward crossover”, this produces a −α3.7 single-gene deletion allele and the reciprocal αααanti3.7 triplicated allele. However, if the crossover occurs between the X2 and X1 boxes (a “leftward crossover”), a −α4.2 single-gene deletion allele and the reciprocal αααanti4.2 triplicated allele are generated (5).nnA Sri Lankan study of individuals with severe to moderate β-thalassemia revealed a 2% frequency of α-globin gene triplications (6), whereas a preliminary study in Hong Kong suggests that the frequency …

FLT-3 aberrations in acute promyelocytic leukaemia: clinicopathological associations and prognostic impact.

FLT‐3 aberrations that occur as an internal tandem duplication (ITD) or a mutation at the activation‐loop position 835, D835, are common in acute promyelocytic leukaemia (APL). We investigated the clinicopathological associations and prognostic impact of FLT‐3 aberrations in a cohort of APL patients. FLT‐3 exons 11 and 12 were amplified by polymerase chain reaction (PCR), and the ITD was recognized as an increase in the size of the PCR product. FLT‐3 exon 17 was amplified, and D835 mutation was identified by loss of an EcoRV site, followed by DNA sequencing. Of 82 patients studied, FLT‐3 aberrations were detected in 35 cases (43%) at diagnosis (ITD: 16; D835 mutation: 18; ITDu2003+u2003D835 mutation: 1). FLT‐3 ITD, but not D835 mutations, was significantly associated with higher presentation white blood cell count (WBC) and microgranular morphology. Early/induction deaths were related to male sex and high presentation WBC. There was a trend for FLT‐3 ITD to be associated with non‐remission (Pu2003=u20030·06). For disease‐free survival, high WBC was the only significant adverse factor. Male sex, high WBC and FLT‐3 ITD were significant adverse factors for overall survival. These findings have important implications on the possible use of FLT‐3 inhibitors in the treatment of APL.

Pernicious anemia in Chinese : A study of 181 patients in a Hong Kong hospital

Abstract: To study the clinical and hematologic features of pernicious anemia in Chinese, we describe 181 Chinese with megaloblastic anemia and low serum cobalamin, in association with either classic Schilling test results (82 patients) or the presence of serum antibody to intrinsic factor (99 patients), encountered in a regional hospital in Hong Kong from May 1994 to May 2005. The median age was 75 years (range, 32-95 yr) and the male to female ratio was 1:1.5. The chief presenting feature was anemia, and fewer than 10% of patients presented predominantly with neurologic deficit. Gastric biopsies of 109 patients showed glandular atrophy in 73, endocrine cell hyperplasia in 5, polyps in 14, adenocarcinoma in 1, and chronic gastritis in the rest. Gastric adenocarcinoma occurred in 1.7% of patients after a median follow-up of 35 months (range, 0.5-132 mo). Diabetes mellitus occurred in 24% of patients and thyroid disease in 7%. No specific ABO blood group was associated with pernicious anemia. Serum antibody to intrinsic factor (73%) occurred more frequently than serum antibody to gastric parietal cell (65%) (p = 0.353). The frequency of serum antibody to gastric parietal cell was higher in male (78%) than in female patients (53%) (p = 0.018). Pernicious anemia is a major cause of megaloblastic anemia in Chinese. Abbreviations: Hb = hemoglobin; GPC = gastric parietal cell; IF = intrinsic factor; MCV = mean corpuscular volume; PA = pernicious anemia.

Diagnostic cues for natural killer cell lymphoma: Primary nodal presentation and the role of in situ hybridisation for Epstein-Barr virus encoded early small RNA in detecting occult bone marrow involvement

Natural killer (NK) cell lymphomas are rare, and atypical features might lead to diagnostic pitfalls. This report describes an unusual patient in whom lymphoma occurred initially as isolated lymph node involvement, an exceptional presentation of an almost exclusively extranodal disease. Furthermore, during the terminal haemophagocytosis in the bone marrow, lymphoma cells lost the expression of the NK cell marker, CD56, making the histopathological diagnosis of bone marrow involvement difficult. This was resolved by in situ hybridisation for Epstein-Barr virus encoded small RNA, which detected occult bone marrow infiltration.

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.

Life-threatening cryoglobulinemia in HCV-negative Southern Chinese and a novel association with structural aortic abnormalities.

Cryoglobulinemia is uncommon in Southern Chinese in Hong Kong, with tropical climates and low incidence of hepatitis C virus (HCV) infection. Eight positive cases were detected among 481 patients screened for cryoglobulins over a 10-year period. Three HCV carriers (38%) ran benign courses. The others included two carriers of hepatitis B virus (HBV), two patients with adenocarcinoma, and one with chronic lymphocytic lymphoma. Four of them (except one HBV carrier) ran fulminant courses and died of cryoglobulin-related complications. Interestingly, all four cases also had structural aortic abnormalities, including multiple dissections, aneurysms, and congenital aortic arch abnormalities, which were often life threatening. The association of aortic abnormality and cryoglobulinemia is hitherto unreported and may be peculiar to our ethnic group. Aggressive control of the cryoglobulin may help to reduce aortic intima damage.

Multiple Minisequencing Screen for Seven Southeast Asian Nondeletional α-Thalassemia Mutations

α-Thalassemia is the most common globin disorder in the world, and the severe forms are especially prevalent among Southeast Asians. It is a disorder of absent or reduced production of α-globin chains resulting from mutations in the α-globin gene cluster on chromosome 16p13.3. Most α-thalassemia mutations involve deletions of one (−α) or both (− −) α-globin genes, whereas point mutations within the α-globin genes (αTα or ααT) are much less frequent. Nonetheless, the number of point mutations that have been described has been steadily increasing, with >40 identified to date (1)(2).nnThe importance of nondeletional α-thalassemia mutations is underscored by the observation that patients with nondeletional hemoglobin (Hb) H disease (αTα/− −) are generally more severely affected and more likely to require transfusions compared with deletional Hb H disease patients (−α/− −) (3). There have also been a few reports of Hb H disease caused by homozygosity or compound heterozygosity of nondeletional mutations involving the α2-globin gene (αTα/αTα) (1)(3). Additionally, nondeletional Hb H disease involving the α2 codon 30 or codon 59 mutation can cause the fatal Hb H hydrops fetalis syndrome, especially if associated with large ζ-α-globin gene deletions (4). In certain regions of Southeast Asia, nondeletional Hb H disease can account for as many as 50% of all Hb H disease patients (3).nnSeveral specific and reliable molecular tests have previously been developed to diagnose and screen the most common deletional (5)(6) and nondeletional (7)(8) α-thalassemia mutations. We now describe a multiplex minisequencing assay to detect seven Southeast Asian nondeletional mutations: Hb Constant Spring (α2 codon 142 TAA→CAA), Hb Pakse (α2 codon 142 TAA→TAT), Hb Quong Sze (α2 codon 125 CTG→CCG), α2 codon 0 Δ1bp (−T), α2 …

Treatment outcome and prognostic factor analysis in transplant-eligible Chinese myeloma patients receiving bortezomib-based induction regimens including the staged approach, PAD or VTD

BackgroundWe have reported promising outcomes using a staged approach, in which bortezomib/thalidomide/dexamethasone was used only in 14 patients with suboptimal response to VAD (vincristine/adriamycin/dexamethasone) before autologous stem cell transplantation (ASCT). Here we compared the outcomes of the staged approach with frontline PAD (bortezomib/doxorubicin/dexamethasone) or VTD (bortezomib/thalidomide/dexamethasone) induction, and analysed prognostic factors for outcome.Patients and methodsNinety-one transplant-eligible Chinese patients received three induction regimens prior to ASCT [staged approach (Nu2009=u200925), PAD (Nu2009=u200931), VTD (Nu2009=u200935)]. and received thalidomide maintenance for 2u2009years post-ASCT.Results43 (47.3%) patients had International Staging System (ISS) III disease. By an intention-to-treat analysis, the overall CR/nCR rate were 37.4% post-induction, and 62.6% post-ASCT. Five-year overall (OS) and event-free (EFS) survivals were 66% and 45.1%. There was no difference of the post-induction CR/nCR rate, EFS or OS between patients induced by these three regimens. Moreover, ISS III disease did not affect CR/nCR rates. Multivariate analysis showed that ISS and post-ASCT CR/nCR impacted OS while ISS and post-induction CR/nCR impacted EFS.ConclusionsThese three induction regimens produced comparable and favorable outcomes in myeloma. The unfavorable outcome of ISS stage III persisted despite upfront/early use of bortezomib. CR/nCR predicted favorable survivals.

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 11.3u2009g/dL). Multiplex ligation-dependent probe amplification (MLPA) revealed a rare 2392u2009bp 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 9.5u2009g/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.