Haematological reference intervals in a multiethnic population.

INTRODUCTION: Similar to other populations, full blood count reference (FBC) intervals in Malaysia are generally derived from non-Malaysian subjects. However, numerous studies have shown significant differences between and within populations supporting the need for population specific intervals. METHODS: Two thousand seven hundred twenty five apparently healthy adults comprising all ages, both genders and three principal races were recruited through voluntary participation. FBC was performed on two analysers, Sysmex XE-5000 and Unicel DxH 800, in addition to blood smears and haemoglobin analysis. Serum ferritin, soluble transferrin receptor and C-reactive protein assays were performed in selected subjects. All parameters of qualified subjects were tested for normality followed by determination of reference intervals, measures of central tendency and dispersion along with point estimates for each subgroup. RESULTS: Complete data was available in 2440 subjects of whom 56% (907 women and 469 men) were included in reference interval calculation. Compared to other populations there were significant differences for haemoglobin, red blood cell count, platelet count and haematocrit in Malaysians. There were differences between men and women, and between younger and older men; unlike in other populations, haemoglobin was similar in younger and older women. However ethnicity and smoking had little impact. 70% of anemia in premenopausal women, 24% in postmenopausal women and 20% of males is attributable to iron deficiency. There was excellent correlation between Sysmex XE-5000 and Unicel DxH 800. CONCLUSION: Our data confirms the importance of population specific haematological parameters and supports the need for local guidelines rather than adoption of generalised reference intervals and cut-offs.

Amplification of BCR-ABL and t(3;21) in a patient with blast crisis of chronic myelogenous leukemia.

The Philadelphia (Ph) chromosome, or t(9;22), is the hallmark of chronic myelogenous leukemia (CML). It results in juxtaposition of the 5' part of the BCR gene on chromosome 22 to the 3' part of the ABL1 gene (previously ABL) on chromosome 9. CML is clinically characterized by three distinct phases: chronic, accelerated, and blast phase. Blast crisis is characterized by the rapid expansion of a population of differentiation arrested blast cells (myeloid or lymphoid cells population), with secondary chromosomal abnormalities present. We report a case of myeloid blast crisis of CML resistant to imatinib mesylate and chemotherapy. By use of cytogenetic, fluorescence in situ hybridization, and comparative genomic hybridization methods, we identified a cluster of BCR-ABL amplification on inverted duplication of the Ph chromosome with t(3;21)(q26;q22) and increased genomic levels of the RUNX1 gene (previously AML1). The t(3;21)(q26;q22) is a recurrent chromosomal abnormality in some cases of CML blast phase and in treatment-related myelodysplastic syndrome and acute myeloid leukemia. Amplification or copy number increase of RUNX1 has been reported in childhood acute lymphoblastic leukemia. Our study indicated that the progenitor of CML was BCR-ABL dependent through the amplification of Ph chromosome as a mechanism of resistance to imatinib therapy. The coexistence of BCR-ABL and t(3;21)(q26;q22) with RUNX1 rearrangement might play a pivotal role in the CML blast transformation.

Cytomegalovirus in the perilymphatic fluid.

OBJECTIVE: The incidence of congenital cytomegalovirus (CMV) infection is approximately 1% of neonates. Ninety percent of congenitally infected infants are "asymptomatic;" they have no signs or symptoms at birth. The prevalence of congenital CMV in the profoundly deaf population and the pathogenesis of deafness from CMV are unknown. The objective of this study is to determine whether CMV can be demonstrated and quantified in perilymphatic fluid of patients with congenital CMV infection and sensorineural hearing loss (SNHL) using a quantitative real-time polymerase chain reaction (QRTPCR). STUDY DESIGN: Prospective case series. METHODS: Perilymphatic fluid was collected at the time of cochlear implantation from children with known or radiologic evidence of congenital CMV infection and analyzed for the presence of CMV using QRTPCR. Blood was collected and analyzed for CMV using QRTPCR, serology, and culture. CMV was quantified in perilymphatic fluid and compared with that present in the patient's blood. RESULTS: Perilymphatic fluid and blood was collected from six children. QRTPCR was positive for CMV in the perilymphatic fluid of four patients. Blood analyzed with QRTPCR, and culture was negative in all patients. CONCLUSIONS: CMV can be demonstrated and quantified in perilymphatic fluid using QRTPCR. Refinements in our technique and sampling of perilymphatic fluid from a large population of children with congenital SNHL and unknown etiology can determine the prevalence of CMV-mediated profound HL.

Unusual immunophenotype of CD8+ T cells in familial hemophagocytic lymphohistiocytosis.

Familial hemophagocytic lymphohistiocytosis (FHL) is an inherited, fatal disorder of infancy. We report here a 17-day-old female infant who presented with high fever, hepatosplenomegaly, hypertriglyceridemia, hypofibrinogenemia, thrombocytopenia, and liver failure. Leukocytosis was detected with circulating "atypical" lymphoid cells. Flow cytometric studies revealed expanded subpopulations of CD8+ T cells with unusual immunophenotypic features, including a subset that lacked CD5 expression. A liver biopsy showed hemophagocytic lymphohistiocytosis with exuberant infiltrates of CD8+ T cells that lacked perforin. Mutational studies revealed a 666C-->A (H222Q) missense mutation in the perforin gene. T-cell receptor studies on flow-sorted T-cell subpopulations revealed no evidence of monoclonality. Analysis of T-cell receptor excision circle levels indicated long proliferative history in the aberrant CD8+ T-cell subsets. This case provides an instructive example of uncontrolled reactive proliferation of CD8+ T cells in FHL, resulting in atypical morphology and unusual immunophenotypic features that might suggest malignancy in other clinical settings.