Search

A prospective study on the microbes isolated from the alimentary tract in 120 bone marrow transplant (BMT) recipients (1991-1993) was undertaken to define the spectrum of organisms isolated under antimicrobial prophylaxis, their temporal sequence of emergence, and the associated morbidity and mortality. Clostridium difficile (n = 20), isolated in the pre-engraftment and early post-engraftment periods (day 2-45 post-BMT), was the most common microbe recovered from stool of patients with diarrhea. In contrast to previous reports, no significant difference in mortality was observed between patients with and without C. difficile isolated in stool. Two patients had neutropenic ileocecitis with concomitant bacteremia due to Escherichia coli and Klebsiella pneumoniae. One patient was found to have astrovirus gastroenteritis (day 7), and Giardia lamblia was recovered from the stool of another (day -7). Heavy growth of Staphylococcus aureus from direct smear-positive specimens was found from the upper airway of two patients with severe mucositis and complete dysphagia (day 12 and 23). Salmonella spp. of groups B and E were found in the stool of five asymptomatic patients at the time of conditioning. No specific organisms was recovered from the endoscopic brushing of two patients with lower end esophagitis, three patients with upper gastrointestinal bleeding, and three patients with perirectal cellulitis. During the post-engraftment period, five patients had documented cytomegalovirus gastroenterocolitis (days 34-97), one had Mycobacterium chelonae colitis (day 70), and another had nodular gastritis due to Acremonium falciforme (day 270). Overall, only 28% of patients with alimentary tract symptoms/syndrome had specific pathogens isolated from clinical specimens. Differentiation of the causation of alimentary tract symptoms was often difficult because noninfectious complications such as conditioning toxicity, graft-versus-host disease, and its treatment often caused alimentary tract symptoms in addition to predisposed BMT patient to infection. The reluctance of obtaining tissue biopsy for ascertaining the importance of those potential alimentary tract pathogens often dictate the use of empirical treatment.

Seventy-three consecutive cases of childhood acute lymphoblastic leukemia (ALL) diagnosed and managed in Queen Mary Hospital over a 10-year period from 1985 to 1994 were retrospectively analysed for their presenting features and treatment outcome. The 48 boys and 25 girls ranged in age from 0.4 to 14.2 years (median: 4.3 years). Bone and joint pain was a relatively common presenting feature besides fever, hepatosplenomegaly and lymphadenopathy. Immunophenotyping of blast cells showed: 51 B-cell precursor ALL, one B-ALL, 10 T-ALL and three myeloid-antigen positive ALL. Eight cases were unclassified since immunophenotyping had not been performed. Out of the 73 patients, treatment outcome was analysed in 20 cases treated with UKALL-VIII regimen and 28 cases treated with either the UKALL-XI regimen or the Hong Kong Children Cancer Study Group (HKCCSG) protocol which was modelled upon UKALL-XI. Although complete remission rates were similar between the two groups, patients treated with the former regimen that was less intensified suffered more relapses than the latter (56 per cent versus 21 per cent, P = 0.04). There were, however, no significant differences both in event-free survival (38.2 +/- 11.2 per cent versus 71.3 +/- 9.3 per cent, P = 0.12) and overall survival (70.0 +/- 10.2 per cent versus 79.6 +/- 8.3 per cent, P = 0.41) between the two groups at 3 years by long-rank test. With the use of risk-directed therapy and improved supportive care, two-thirds of our patients are able to enjoy long-term event-free survival.

Background: The thalassemias are common in southern China. We determined the prevalence of heterozygous carriers of these genetic disorders in Hong Kong and assessed the feasibility of a community-based screening program., Methods: An educational and screening program for the thalassemias was carried out in three high schools with a total of 2420 students. Seventy-five percent of the students agreed to undergo screening, which consisted of blood counts, hemoglobin electrophoresis, serum ferritin measurements, and DNA analyses., Results: Of the 1800 blood samples tested, 150 (8.3 percent) had microcytosis (mean corpuscular volume, <80 microm3). Ninety students (5.0 percent) were carriers of alpha-thalassemia, of whom 81 (4.5 percent) were carriers of the Southeast Asian type of deletion, in which both alpha-globin genes on the same chromosome 16 are deleted. Sixty-one students (3.4 percent) were carriers of either beta-thalassemia or the mutation coding for hemoglobin E. Six students were carriers of both alpha- and beta-thalassemias. On the basis of these figures, the estimated numbers of pregnancies in Hong Kong in which the fetus is at risk for homozygous alpha-thalassemia and beta-thalassemia major or intermedia are 145 and 80 per year, respectively. In Hong Kong the actual numbers of women referred for prenatal diagnoses of these disorders are approximately 95 and 40 per year, respectively., Conclusions: Despite the availability of hospital-based screening and prenatal diagnosis for many years in Hong Kong, many women carrying fetuses at risk for thalassemia are not referred for genetic counseling. A community-based program of education, screening, and counseling is needed in Hong Kong and southern China.

Three consecutive cases of pediatric myelodysplastic syndrome (MDS) diagnosed over a three-year period in Queen Mary Hospital, Hong Kong, were described. Depending on the classification system used, they comprised two cases of chronic myelomonocytic leukemia (CMMoL) of which one can be reclassified as juvenile chronic myeloid leukemia (JCML) and one cases of refractory anemia with excess of blasts (RAEB) or an alternative diagnosis of atypical CML. Cytogenetic abnormalities were detected in all of them on examination of bone marrow cells. Of the two CMMoL, one had monosomy 21, whereas the other had hypodiploidy. The patient with RAEB had a complex karyotype of 46,X,del(X)(q24),t(1;7) (p22;q32),add(15)(q26)(8). The balanced translocation (1;7) seen in this patient was exceedingly rare and, to the best of our knowledge, was reported only twice in the literature. The karyotypic abnormalities that we saw in our patients were not well recognized in pediatric MDS. This report emphasizes the importance of cytogenetic study in children suspected of suffering from MDS, which remains a rare disorder of childhood, and a need to rationalize current classification schemes.

Incidence data of childhood leukaemia (CL) in Hong Kong (1984-90) have been analysed for evidence of variation between small areas. All cases (n=261) were classified by morphological cell type, with the majority (n=205) being acute lymphoblastic leukaemia (ALL), and haematological review has permitted immunophenotypic classification for 73% of these. The data have been examined for evidence of spatial clustering within small census areas (TPUs) and for association with population mixing, with attention focused on those subgroups (especially the childhood peak of ALL--taken here to be diagnoses in children from 24 months up to the seventh birthday--and common ALL) which, it has been hypothesized, may be caused by unusual patterns of exposure and response to common infections. For the whole of Hong Kong, there was evidence of spatial clustering of ALL at ages 0-4 years (P = 0.09) and in the childhood peak (P<0.05). When these analyses were restricted to TPUs where extreme population mixing may have occurred, overall incidence was elevated and significant evidence of clustering was found for ALL (P<0.007) at these ages and for the common ALL in the childhood peak (P = 0.032). Replication of the analyses for subsets of leukaemia that were not dominated by the childhood peak of ALL found no evidence of clustering. This is the first investigation of an association between population mixing and childhood leukaemia in Asia and the first to include clustering and to consider particular subsets. The results are supportive of the 'infectious' aetiology hypothesis for subsets of childhood leukaemia, specifically common ALL in the childhood peak.

A 13-year-old girl with Plesiomonas shigelloides septicemia is reported. The infection occurred while she was receiving an allogeneic bone marrow transplantation for acute promyelocytic leukemia. Treatment with ciprofloxacin was successful. Twenty-one cases of Plesiomonas septicemia have been reported in the literature. Immunocompromised hosts, especially neonates, are commonly affected. The case mortality rate is high, with 13 of the reported patients dying of the infection. Successful treatment relies on the early identification of the organism and implementation of effective antibiotics.

We report a girl with severe combined immunodeficiency (SCID) who had a paternal T-depleted bone marrow transplant (BMT) when 11 months old. Engraftment was documented but karyotyping of marrow cells 1 year after BMT showed recipient metaphases (XX) only. However, she remained clinically well and further analysis y karyotyping of PHA-cultured peripheral blood mononuclear cells (PBMC) showed donor metaphases (XY) only. DNA fingerprinting confirmed mixed chimerism in the peripheral blood. The granulocytes were of recipient origin and the PBMC of mixed origin, the donor proportion of which increased after culture with PHA. Using simultaneous immunophenotyping and fluorescence in situ hybridisation (FISH) with chromosomes X and Y-specific probes, circulating T cells were demonstrated to be of donor origin whereas B cells and myeloid cells were mostly of recipient origin.

Infection with Listeria monocytogenes is uncommon in patients receiving cytotoxic chemotherapy, and is even rarer among recipients of bone marrow transplantation. Hemosiderosis, either idiopathic or caused by transfusion, appears to be another risk factor. We report a 3-year-old Chinese girl with transfusion-dependent Diamond-Blackfan syndrome who had L. monocytogenes septicemia when she received an allogeneic bone marrow transplantation. She was treated successfully with intravenous ampicillin. Our case adds to the clinical evidence that patients with iron overload are susceptible to listeriosis, particularly when they are immunocompromised and do not receive iron-chelation treatment.

We present the cytogenetics and immunophenotypes of 55 cases of childhood acute lymphoblastic leukemia in Hong Kong. Although the pattern of immunophenotypes is similar to that of the west, hyperdiploidy is rarely observed locally. Our preliminary analysis also reveals some new translocations.

Translocation (9;11)(p22;p15) was found in a patient with acute biphenotypic leukemia. This has not been reported previously although both chromosome bands 9p22 and 11p15 have been involved in a variety of leukemias with diverse phenotypes.

Reactive hemophagocytic syndrome, which is characterized by systemic proliferation of benign hemophagocytic histiocytes, usually presents as an acute febrile illness with pancytopenia and hepatosplenomegaly. The commoner diseases associated with the syndrome are infection and malignant lymphoma. In this report, eight cases of reactive hemophagocytic syndrome occurring in infants and young children are described. Unlike the disease occurring in adults, there is frequent occurrence of atypical mononuclear cells both in the peripheral blood and bone marrow. The morphological spectrum of these atypical cells is however still within that seen in infectious mononucleosis, and their reactive nature is substantiated by their spontaneous disappearance and subsequent recovery of the patients. It is important to distinguish this reactive proliferation from the neoplastic cells of 'malignant histiocytosis' or malignant lymphoma, since cytotoxic drugs are not warranted for treatment of this non-neoplastic condition.

Interstitial deletion of the long arm of chromosome 9 (9q-) is an uncommon karyotypic abnormality in acute myeloid leukemia (AML). We report a case of acute myeloid leukemia, M6 according to the FAB criteria, in which 9q- was the sole karyotypic abnormality. From our own experience and that in the literature, interstitial 9q- seems to be associated with two specific morphologic/cytogenetic categories: AML M2 and t(8;21)(q22;q22)/trisomy 21; and as the sole karyotypic aberration in AML M1/M2(M6) with dyserythropoiesis. Examination of the published karyotypes shows that 9q13 to 9q21 is the commonest deleted segment, suggesting that this region may carry genes important in leukemogenesis.

Trisomy 4 is an uncommon numerical chromosomal aberration in acute leukemia. We describe three cases of trisomy 4, occurring in two patients with acute myeloid leukemia (M1 and M5a) and in one patient with T-cell acute lymphoblastic leukemia. Our results suggest that trisomy 4 may occur in a broader range of hematologic and malignancies than previously described.

A 13-year-old girl presented with two spontaneously reversible episodes of marrow hypoplasia. She subsequently developed acute lymphoblastic leukaemia (ALL) 8 months later. Southern analysis showed identical clonal immunoglobulin heavy chain gene rearrangement bands in the leukaemic cells as well as the marrow cells obtained at the two hypoplastic episodes. Hypoxanthine phosphoribosyl transferase polymorphism studies showed that the ALL blast cells, bone marrow and peripheral blood cells during the two hypoplastic episodes all exhibited clonal haematopoiesis with the same X-chromosome inactivated. This case provides strong evidence that aplastic anaemia and ALL may represent evolution of the same abnormal clone.

In Langerhans' cell histiocytosis, the prognostic significance of pulmonary disease is controversial. The clinical and radiological features and lung function tests of Langerhans' cell histiocytosis patients presenting to a single tertiary referral center between 1981 and 1987 were reviewed. Age at diagnosis ranged from 2 weeks to 16 years (median 1.7 years) and the male-female ratio was 2.4:1. No child presented with lung involvement alone. In 18 (40%) of 45 patients with multisystem disease there was clinical and/or radiological evidence of lung pathology. Another 6 children (13%) with normal chest roentgenograms had abnormal lung function tests, suggesting subclinical ("occult") involvement. Those with overt lung disease tended to present at a younger than average age (median 0.6 years). The most common functional disturbance was reduced lung or respiratory compliance with reduced lung volumes. Patients with and without lung involvement showed a similar pattern of involvement of other organs, with skin and bone most commonly affected. Of the 45 children with multisystem disease, 38 (84%) survived 2 to 7 years after diagnosis; there was a similar proportion of deaths in children with and without lung involvement. It is concluded that lung involvement occurs in nearly half of young children with multisystem Langerhans' cell histiocytosis but does not adversely affect outcome.

Arteriovenous malformations of the uterus are extremely rare and they occur either in congenital or acquired forms. The most common clinical presentation is abnormal uterine bleeding, which may be aggravated by therapeutic curettage. Because of their rare incidence and clinical importance in management of patients, we report a case of arteriovenous malformation causing serious bleeding during a hysterectomy for uterine leiomyoma. The patient was a 47-year-old multiparous woman who had a history of chronic vaginal bleeding for one year. Numerous anomalous blood vessels draining into the right and left uterine arteries were found on the anterior wall of the uterus and parametrium.

Objective: To characterize an unusual mode of presentation of systemic lupus erythematosus: acute and severe pancytopenia related to reactive hemophagocytosis., Design: Retrospective case series., Setting: Two general community hospitals in Hong Kong., Patients: Six patients presenting with a reactive hemophagocytic syndrome, identified over a 3.5 year period, diagnosed with systemic lupus erythematosus according to the criteria of the American Rheumatism Association., Results: In addition to severe pancytopenia and marrow hemophagocytosis, other characteristic features were fever, hypocomplementemia, high antinuclear antibody titer, and cutaneous and visceral vasculitis. There was no evidence of an underlying infection. The pancytopenia responded dramatically to treatment with steroids., Conclusion: Recognition of the acute lupus hemophagocytic syndrome and distinction from an infection-associated hemophagocytic syndrome is important because it responds well to steroid therapy. The evaluation of patients presenting with a hemophagocytic syndrome should include serologic tests for systemic lupus erythematosus.

A young Hong Kong Chinese male patient with fever of unknown origin is presented. The diagnosis of acquired immunodeficiency syndrome was made only 5 months after the onset of his illness. The lack of awareness of the syndrome might account for the delay in the diagnosis. The legal attitude towards homosexuality might have an adverse effect on epidemiological studies of AIDS in Hong Kong.