Long-term clinical outcomes after Streptococcus bovis isolation in asymptomatic blood donors in Hong Kong.

BACKGROUND: Risk of transfusion-transmitted bacterial sepsis has been substantially reduced by a bacterial surveillance program (BST). However, new problems emerge as asymptomatic bacteremia is detected in blood donors. Streptococcus bovis bacteremia, which is known to associate with infective endocarditis and colonic carcinoma, is an example. STUDY DESIGN AND METHODS: A retrospective study was conducted to examine the demographic and clinical outcome of this group of donors. All confirmed culture-positive cases under the BST were retrieved and those donors with S. bovis bacteremia were contacted for follow-up. Viable culture samples were sent for detailed microbiologic analysis. RESULTS: From 1998 to 2012, a total of 16 donors were found to have S. bovis bacteremia, giving an estimated prevalence of 1 in 110,800 donations. They consisted of nine men and seven women with median age of 43.5 years. Eight donors had undergone colonoscopy with colonic carcinoma detected in two and benign adenoma in four. Five of the 16 isolates could be retrieved for 16S DNA sequencing. Four were identified as S. gallolyticus ssp. pasteurianus and one as S. gallolyticus ssp. gallolyticus. The two patients with colonic carcinoma had one each of subspecies pasteurianus and gallolyticus. CONCLUSION: The findings highlight a close association of S. bovis and colonic carcinoma. We recommend prompt donor follow-up if S. bovis bacteremia is detected. Besides, all confirmed S. bovis should be fully characterized by molecular technique.

A study of the predonation hemoglobin and iron status among Hong Kong Chinese blood donors.

BACKGROUND: Predonation hemoglobin (PDH) is used to safeguard donors' welfare, and low hemoglobin (Hb) is known to be the most frequent reason for donor deferral. A study was initiated to assess the PDH and iron status of blood donors in Hong Kong. STUDY DESIGN AND METHODS: This observational study was designed with four groups of whole blood donors invited (group 1-eligible first time donors, group 2-eligible repeat donors with zero or one donation in preceding 12 months, group 3-eligible repeat donors with at least two donations in preceding 12 months, group 4-repeat donors being deferred for low PDH). Predonation blood samples were obtained for blood counts and iron status. Mann-Whitney test, Kruskal-Wallis test, and chi-square test for trend were applied for statistical analysis. RESULTS: A total of 836 donors were recruited, of which 35 were excluded because of hemoglobinopathy. An inverse relationship between serum ferritin level and number of donations in the preceding 12 months was observed in both sexes. Iron deficiency was significantly seen in 35.1% of male and 65.3% of female deferred donors. More importantly, up to 7.2, 5.8, and 29.5% of the female donors in groups 1, 2, and 3 were found to be iron deficient despite having a high enough PDH. CONCLUSION: This is the first study to assess PDH and iron status in Chinese blood donors. Iron depletion is noted with increasing number of blood donations in the preceding 12 months. Advice on iron repletion is a necessary step for donor welfare and strategies should be developed to ensure that donors have adequate PDH.

Vitamin B12 deficiency--need for a new guideline.

OBJECTIVES: Many patients with vitamin B12 deficiency do not have anemia or macrocytosis, but the prevalence of B12 deficiency in patients without macrocytosis is not known. METHODS: We investigated the prevalence of B12 deficiency among patients with normocytosis and microcytosis and recommended a screening strategy. All patients (n = 3714) with serum B12 measured at the Prince of Wales Hospital in 1996 were reviewed. The prevalence of serum B12 less than 140 pmol/L was determined for the following patient subgroups: younger than 70 y, older than 70 y, anemic, non-anemic, macrocytic, normocytic, microcytic, documented iron deficiency, and documented thalassemia. RESULTS: The prevalence of B12 deficiency (<140 pmol/L) ranged from 4.8% to 9.8% among the different subgroups. CONCLUSIONS: Whatever screening criteria were used, a significant number of B12-deficient patients will be missed. Therefore, there may be a case for universal vitamin B12 screening.

TEL/AML1 rearrangement and the prognostic significance in childhood acute lymphoblastic leukemia in Hong Kong.

The TEL/AML1 rearrangement has been implicated as an independent good prognostic factor in pediatric acute lymphoblastic leukemia (ALL). We examined TEL/AML1 using nested reverse-transcription polymerase chain reaction (RT-PCR) and correlated TEL/AML1 with cytogenetics and immunophenotypes in 75 consecutively analyzed Chinese children with ALL in Hong Kong. TEL/AML1 was detected in 17.9% (12/67) B-lineage ALL at diagnosis but not in 8 T-ALL children or in 34 adults with ALL. E2A/PBX1, MLL/AF4, and BCR/ABL were not found in TEL/AML1+ patients. Coexpression of cross-lineage antigens was associated with TEL/AML1 gene fusion (p = 0.032), with CD13 in 80% (4/5) TEL/AML1+ cohort. Chromosomal abnormalities were demonstrated in 50% of the TEL/AML1+ ALL; however, a cryptic t(12;21) was not detected in these cases. Hyperdiploidy of 47-48 chromosomes was encountered in 25%. Deletion of 12p resulting in the loss of the normal allele of TEL and nonspecific del(6q) were noted in 8% (1/12) and 25% (3/12) of the TEL/AML1+ children, respectively. Rapid clearance of TEL/AML1 was noted in 50% of the patients on completion of the induction therapy; however, 16.7% (2/12) TEL/AML1+ ALL relapsed at a mean of 48.6 months from diagnosis (25 months off-therapy). The incidence of relapses of TEL/AML1+ ALL was comparable to that at diagnosis in B-lineage ALL (14.3% [2/14] vs. 17.9% [12/67], p > 0.05). The relapse rate in TEL/AML1+ ALL was similar to that of TEL/AML1- ALL (16.7% [2/12] vs. 20.6% [13/63], p > 0.05). The duration of first complete remission in TEL/AML1+ ALL was significantly longer as compared to TEL/AML1- ALL (mean [range] in month: 48.6 [47.2 - 50] vs 14.6 [2.9 - 42.3], p < 0.0001). Irrespective of TEL/AML1 rearrangement, the probabilities of the five-year overall survival and the event-free survival of patients were comparable (overall survival: 100% vs. 72.3%, p = 0.166 and event-free survival: 60% vs. 56.2%, p = 0.343). Our data would not suggest a less aggressive treatment regimen for TEL/AML1+ ALL.

Cord blood collection before and after placental delivery: levels of nucleated cells, haematopoietic progenitor cells, leukocyte subpopulations and macroscopic clots.

The number of nucleated cells infused into the recipient of a cord blood (CB) transplant has emerged as the most important factor affecting the probability and speed of engraftment. At present, there is no international consensus on the procedure of CB collection in the maternity ward. In order to maximise the yield of viable cells in a CB unit, we aimed to investigate the efficiency of CB collection, with respect to the time of delivery of the placenta. We analysed stem and progenitor cells in terms of CD34+ cell content and colony-forming activities, lymphocyte subpopulations and the presence of macroscopic clots in 93 paired CB samples, collected before and after the delivery of the placenta. Our results demonstrated that the median concentrations of nucleated cells and total colony-forming unit (CFU) were significantly lower in CB collected after placenta delivery by 9.5% (P < 0.001) and 11.6% (P = 0.015), respectively, when compared to their counterparts collected before placental delivery. A reduction of granulocytes (P < 0.001), monocytes (P < 0.001) and CD19+ B lymphocytes (P = 0.031) was observed, with no significant change in the proportion of T cell subsets (CD4+, CD8+ cells) or activated T cells (CD25+, CD45RO+ cells) in samples collected after placenta delivery. The incidence of macroscopic clots was also higher in these samples (31% vs 1%, P < 0.001). The reduction of stem and progenitor cells correlated significantly with that of major cell populations, indicating a general cell loss, possibly due to clotting activities developed with time. Our study has documented strong evidence for recommending the collection of CB before the delivery of the placenta.

Haemostatic changes during surgery for primary brain tumours.

OBJECTIVE: Primary brain tumours may be associated with coagulation disorders which can pose intraoperative and postoperative management difficulties. The aim was to evaluate the coagulation profile of patients with brain tumours undergoing surgery using thromboelastography (TEG) in combination with simple laboratory tests. METHODS: Fifty adult patients with primary brain tumours larger than 4 cm in maximum diameter and no history of coagulation disorders were studied in a prospective, observational manner over a one year period. Preoperative, intraoperative, and postoperative measurements included haemoglobin concentration, platelet count, prothrombin and partial thromboplastin times, fibrin(ogen) degradation product concentration, D-dimer concentration, and TEG. RESULTS: Eleven patients (22%) had abnormal intraoperative TEGs, of whom six (12%) subsequently developed haematomas requiring surgical evacuation. The coagulopathy seemed to be hyperfibrinolysis in two cases (4%) and disseminated intravascular coagulation in four (8%). There was no preoperative difference in reaction time (R time) for clot formation between the non-haematoma and haematoma groups(mean 11.44 (SD 3.42) v 12.33 (2.50) min, P=0.46). However, when other preoperative indices were compared, in the non-haematoma group, K time (time to reach a clot amplitude of 20 mm) was shorter (6.72 (2.15) v 10.56 (3.50) min, P=0.001), rate of clot growth (å) was faster (43.67 degrees (7.53) v 27.11 degrees (5.42), P<0.0001) and maximum amplitude of clot strength (MA) was greater (52.64 (7.85) v 40.33 (6.59) mm, P<0.001). Intraoperatively, R time was significantly shortened in the non-haematoma group, (7.67 (1.78) min, P<0.0001) unlike the haematoma group (10.67 (1.58) minutes, P=0.11). CONCLUSIONS: Although these results indicate a general hypercoagulability during brain tumour surgery, in certain cases, a predisposition towards hypocoagulability may exist even before surgery, detectable only when the physical characteristics of clot formation are studied by TEG. Judicious replacement of clotting factors, platelets, and antifibrinolytic agents should be considered intraoperatively if the TEG is abnormal, without waiting for laboratory test results.

A more immunosuppressive pre-transplant conditioning may be required for Chinese patients with thalassaemia.

Bone marrow transplantation was performed on 14 Chinese patients with transfusion dependent thalassaemia major (n = 13) and haemoglobin H disease (n = 1). The donors were HLA identical siblings. The source of haematopoietic stem cells were from bone marrow (n = 13) and umbilical cord blood (n = 1). The pre-transplant conditioning regimens were (1) busulphan 14 mg/kg and cyclophosphamide 200 mg/kg in two patients; (2) busulphan 16 mg/kg, cyclophosphamide 200 mg/kg and anti-thymocyte globulin 110 mg/kg in five patients; (3) busulphan 16 mg/kg, cyclophosphamide 150 mg/kg and anti-thymocyte globulin 110 mg/kg in seven patients. Graft-versus-host disease prophylaxis was cyclosporin A and methotrexate. All patients engrafted and achieved stable haematopoiesis except the one who underwent the umbilical cord blood transplant, who had autologous marrow recovery. One patient who had stable engraftment rejected the marrow graft and developed aplastic anaemia 4 months after BMT. This patient had a second BMT but rejection recurred again. She eventually died of septicaemia. The other 12 patients were transfusion independent and disease free. The majority have gone back to school or work. Disease-free and actuarial survival probability were 85 and 93%, respectively with a median follow-up time of 30 months (13 to 42 months). Our data suggest that BMT from HLA identical siblings for transfusion dependent thalassaemia gives a high chance of cure with acceptable mortality and morbidity, and that a more immunosuppressive pre-transplant conditioning schedule may be required to prevent rejection.

Plasma cells with iron inclusions in two non-alcoholic Chinese women.

Plasma cells with iron granules are rare, especially among non-alcoholic individuals. We report two teetotaller Chinese women with nasopharyngeal carcinoma and non-Hodgkin's lymphoma, whose bone marrow studies revealed plasma cells with inclusions morphologically compatible with iron granules. The iron nature of the granules was confirmed by elemental analysis. The clinical significance and the exact mechanism of formation of these iron inclusions in plasma cells remain unknown.

Small cell variant of Ki-1 lymphoma associated with myelofibrosis and a novel constitutional chromosomal translocation t(3;4) (q13;q12).

An unusual case of small cell variant of Ki-1 non-Hodgkin's lymphoma diagnosed one year after an original diagnosis of idiopathic myelofibrosis is reported. On the second occasion, the patient presented with fever, lymphadenopathy and hepatosplenomegaly. A lymph node biopsy specimen confirmed a diagnosis of small cell variant of Ki-1 lymphoma. A repeat bone marrow biopsy specimen showed myelofibrosis with no evidence of lymphomatous infiltration, but cytogenetic studies on blood, bone marrow and skin fibroblasts revealed a novel chromosomal translocation t(3,4)(q13;q12).

Association between t(2;9)(p12;p23) and early B-precursor acute lymphoblastic leukemia.

We report the occurrence of t(2;9)(p12;p23) in a 20-month-old girl with early B-precursor acute lymphoblastic leukemia (ALL). This translocation has only been reported once before in an adult case of early B-precursor ALL with t(4;11)(q21;q23). We suggest that t(2;9)(p12;p23) may be associated with this particular phenotype of ALL.