Comparison of green pit viper and Agkistrodon halys antivenom in inhibition of coagulopathy due to Trimeresurus albolabris venom: an in-vitro study using human plasma.

INTRODUCTION: There are two antivenoms that may be administered in Hong Kong following a bite by Trimeresurus albolabris: the green pit viper antivenom from the Thai Red Cross Society in Thailand and the Agkistrodon halys antivenom from the Shanghai Institute of Biological Products in China. Both are recommended by the Central Coordinating Committee of Accident and Emergency Services of the Hospital Authority for treating patients with a bite by Trimeresurus albolabris. The choice of which antivenom to use is based on physician preference. This study aimed to compare the relative efficacy of the two antivenoms. METHODS: This in-vitro experimental study was carried out by a wildlife conservation organisation and a regional hospital in Hong Kong. Human plasma from 40 adult health care worker volunteers was collected. The Trimeresurus albolabris venom was added to human plasma and the mixture was assayed after incubation with each antivenom (green pit viper and Agkistrodon halys) using saline as a control. Fibrinogen level and clotting time in both antivenom groups were studied. RESULTS: The mean fibrinogen level was elevated from 0 g/L to 2.86 g/L and 1.11 g/L after the addition of green pit viper antivenom and Agkistrodon halys antivenom, respectively. When mean clotting time was measured, the value was 6.70 minutes in the control, prolonged to more than 360 minutes by green pit viper antivenom and to 19.06 minutes by Agkistrodon halys antivenom. CONCLUSIONS: Green pit viper antivenom was superior to Agkistrodon halys antivenom in neutralisation of the thrombin-like and hypofibrinogenaemic activities of Trimeresurus albolabris venom.

The impact of hepatitis B virus (HBV) infection on clinical outcomes of patients with diffuse large B-cell lymphoma.

We performed a retrospective study to analyse the characteristics and clinical outcomes of diffuse large B-cell lymphoma (DLBCL) patients with hepatitis B virus (HBV) infection and compare with those without HBV infection. The occurrence of hepatitis after withdrawal of prophylactic antiviral treatment on completion of chemotherapy was also assessed. The HBsAg-positive patients were given prophylactic antiviral treatment until 6 months after finishing chemotherapy. A total of 81 patients were recruited with 16 in the HBsAg-positive group and 65 in the HBsAg-negative group. The clinical characteristics were similar in both groups of patients. There was no significant difference in complete remission rate between the two groups (63% in HBsAg-positive group vs. 54% in HBsAg-negative group, P = 0.59). There was also no statistically significant difference in overall survival between the two groups (P = 0.23). Four of the 16 HBsAg-positive patients (25%) had hepatitis after cessation of chemotherapy and prophylactic lamivudine. The mean time of onset of hepatitis was 3 months after stopping lamivudine. In conclusion, HBV infection did not appear to affect the prognosis of DLBCL patients given antiviral prophylaxis. It is reasonable to consider prophylactic antiviral therapy to extend to at least one year on completion of chemotherapy.

Life expectancy, standardized mortality ratios, and causes of death in six rheumatic diseases in Hong Kong, China.

OBJECTIVE: To examine the life expectancy, standardized mortality ratios (SMRs), and causes of death in 6 groups of patients from Hong Kong with different rheumatic diseases. METHODS: Patients with a diagnosis of systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), ankylosing spondylitis (AS), psoriatic arthritis (PsA), systemic vasculitis (SV), or systemic sclerosis (SSc) registered in 37 public hospitals between 1999 and 2008 were identified in the hospital registry. SMRs were calculated by comparing the mortality rate in patients with each disease with that in the general population. Life expectancy was calculated by abridged life-table analysis, and the causes of death were compared. RESULTS: In 2008, data on 8,367 RA, 5,243 SLE, 2,154 AS, 1,636 SV, 778 PsA, and 449 SSc patients were available in our registry. The age- and sex-adjusted SMRs were highest for SLE (5.25 [95% confidence interval 4.79-5.70]), SSc (3.94 [95% confidence interval 3.20-4.68]), and SV (2.64 [95% confidence interval 2.36-2.93]). In female patients, the loss in life expectancy was greatest for SSc (34.1 years), SV (19.3 years), and SLE (19.7 years). In male patients, the loss in life expectancy was highest for SV (28.3 years), SLE (27 years), and SSc (16 years). There were 2,486 deaths during the study period (1999-2008), and the principal causes were infections (28%), cardiovascular complications (18%), cancer (16%), and disease activity (7%). Infection was the leading cause of death in SLE, RA, AS, and PsA, whereas deaths from disease-related activity and cardiovascular complications were most frequent in SSc. Cancer was the most common cause of death in SV. CONCLUSION: Our findings indicate that patients with SLE, RA, AS, PsA, SV, and SSc have increased mortality rates and reduced life expectancy. SLE has the highest adjusted SMR, and female SSc patients have the greatest loss in life expectancy. Infection is the leading cause of death, followed by cardiovascular complications and malignancies.

Common association of haemolytic uraemic syndrome with invasive Streptococcus pneumoniae infection in five Chinese paediatric patients.

Haemolytic uraemic syndrome is an important cause of acute renal impairment in childhood. We review the incidence, and clinical and laboratory features of haemolytic uraemic syndrome in a Chinese population. Five patients were identified from 2006 to 2008. All patients were young children with associated invasive Streptococcus pneumoniae pulmonary infection. Serotypes 3, 14, and 19A were confirmed in four patients. The classical post-diarrhoeal form associated with Escherichia coli (O157:H7) infection was not seen. One patient died of acute respiratory failure. Streptococcus pneumoniae infection, as an associated condition in haemolytic uraemic syndrome, is important and relatively common in Chinese patients, especially among children. The acute clinical picture is similar to that reported in the western literature, except for an uncommon association with meningitis. The medium-term renal outcome of the Chinese population appears to be more favourable than the Caucasians. Widespread vaccination against Streptococcus pneumoniae may have resulted in changes in bacterial epidemiology and clinicians should be continuously aware of this severe disease. The use of washed blood components for transfusion in the acute stage requires further study.

BCR-ABL mutational studies for predicting the response of patients with chronic myeloid leukaemia to second-generation tyrosine kinase inhibitors after imatinib failure.

Imatinib is the standard treatment for chronic myeloid leukaemia. BCR-ABL kinase domain mutation is the commonest mechanism implicated in imatinib resistance. In in-vitro studies, kinase domain mutations are variably resistant to second-line agents. We performed BCR-ABL kinase domain mutational studies in 25 patients in five institutions who failed imatinib and were treated with either nilotinib or dasatinib, to see if their mutational status would predict their clinical responses. Kinase domain mutations involving 11 amino acid substitutions were found in 12 (48%) patients. Most patients showed single kinase domain mutations. There was some concordance between reported drug sensitivity patterns and patient responses. Discordant responses could be related to drug dosage variations and unknown BCR-ABL independent mechanisms. The response prediction for patients with multiple kinase domain mutations was challenging and their mutational patterns could change after tyrosine kinase inhibitor therapy. Although BCR-ABL kinase domain mutational analysis has limitations as a means of predicting the clinical response to second-line tyrosine kinase inhibitors, it helps inform therapy decisions in the management of chronic myeloid leukaemia after imatinib failure.

Next-generation sequencing with a myeloid gene panel in core-binding factor AML showed KIT activation loop and TET2 mutations predictive of outcome.

Clinical outcome and mutations of 96 core-binding factor acute myeloid leukemia (AML) patients 18-60 years old were examined. Complete remission (CR) after induction was 94.6%. There was no significant difference in CR, leukemia-free-survival (LFS) and overall survival (OS) between t(8;21) (N=67) and inv(16) patients (N=29). Univariate analysis showed hematopoietic stem cell transplantation at CR1 as the only clinical parameter associated with superior LFS. Next-generation sequencing based on a myeloid gene panel was performed in 72 patients. Mutations in genes involved in cell signaling were associated with inferior LFS and OS, whereas those in genes involved in DNA methylation were associated with inferior LFS. KIT activation loop (AL) mutations occurred in 25 patients, and were associated with inferior LFS (P=0.003) and OS (P=0.001). TET2 mutations occurred in 8 patients, and were associated with significantly shorter LFS (P=0.015) but not OS. Patients negative for KIT-AL and TET2 mutations (N=41) had significantly better LFS (P<0.001) and OS (P=0.012) than those positive for both or either mutation. Multivariate analysis showed that KIT-AL and TET2 mutations were associated with inferior LFS, whereas age ⩾40 years and marrow blast ⩾70% were associated with inferior OS. These observations provide new insights that may guide better treatment for this AML subtype.

A case of Streptococcus mitis endocarditis successfully treated by linezolid.

We report the successful treatment of infective endocarditis caused by Streptococcus mitis with linezolid in a patient with pre-existing valvular heart disease. The patient had multiple allergies to conventional antibiotics. Linezolid may provide an oral alternative in the treatment of infective endocarditis in patients with adverse drug reactions to traditional antibiotic regimens.

Two balanced and novel chromosomal translocations in myeloid malignancies. characterization by multiplex fluorescence in situ hybridization.

We describe two novel chromosomal translocations in two cases of leukemia in which these translocations were further characterized as the sole acquired karyotypic abnormality by mutliplex fluorescence in situ hybridization (M-FISH). They comprised a case of acute myeloid leukemia with t(6;10)(q21;p12) and a case of chronic myelomonocytic leukemia with t(5;12)(q34;q24). To the best of our knowledge, these two balanced translocations are novel and are hitherto unrecognized in hematologic malignancies. While the clinical and pathogenic significance of these translocations remains to be defined, the present report illustrates that M-FISH technology contributes to the exclusion of subtle or cryptic translocations in sole karyotypic aberrations and the confirmation of novel chromosomal arrangements in neoplastic disorders.

Cytomegalovirus infection associated with clonal proliferation of T-cell large granular lymphocytes: causal or casual?

Clonal proliferation of T-cell large granular lymphocytes (LGL) is an indolent disorder characterized by splenomegaly, lymphocytosis and frequent manifestations of immune disturbances. The LGL are CD3(+) CD4(-) CD8(+) CD56(-). The clonality of the tumor cell population is often only demonstrable by T-cell receptor (TCR) gene rearrangement study because chromosomal abnormality is distinctly rare. We describe a case of T-cell LGL leukemia that presented initially as cytomegalovirus infection. The leukemic LGL are shown to be clonal by both TCR gene rearrangement and chromosomal studies. They persist after subsidence of the cytomegalovirus infection.

Molecular characterization of der(15)t(11;15) as a secondary cytogenetic abnormality in acute promyelocytic leukemia with cryptic PML-RAR alpha fusion on 17q.

A case of acute promyelocytic leukemia (APL) with cryptic PML-RAR alpha fusion on 17q and add(15p) as a secondary abnormality was characterized using molecular cytogenetic techniques. Spectral karyotyping (SKY) showed that chromosome 11 material was added to 15p, forming a der(15)t(11;15), which was refined to der(15)t(11;15)(q13.2;p13) with information obtained by comparative genomic hybridization (CGH). Interstitial insertion of chromosome 15 material into chromosome 17q was found by fluorescence in situ hybridization (FISH) with whole chromosome painting (WCP) probes. This study illustrates the necessity of a combination of molecular cytogenetics to decipher complex karyotypic abnormalities and cryptic translocations in leukemia.

Absence of microsatellite instability in primary myelodysplastic syndrome.

Using polymerase chain reaction (PCR), we examined a panel of 10 microsatellite markers (BAT26, BAT40, D2S123, D4S171, D8S87, D10S197, D12S89, Tp53, D18S58, PLCpr) covering nine chromosomal arms for microsatellite instability (MSI) in 29 patients with primary MDS. Bone marrow DNA was compared with corresponding constitutional DNA derived from buccal epithelial cells. Apart from BAT26 and BAT40 that were mononucleotide (poly A) repeats, the others were dinucleotide (CA) repeats. The patients comprised 10 cases of refractory anemia (RA), three cases of refractory anemia with ringed sideroblasts (RARS), nine cases of refractory anemia with excess of blasts (RAEB), four cases of refractory anemia with excess of blasts in transformation (RAEBt), and three cases of chronic myelomonocytic leukemia (CMML). Serial samples were available in seven patients, in which four showed transformation into higher disease grade or acute myeloid leukemia (AML). Genetic alterations at one locus (three at D2S123, one at D4S171) were evident in four cases, and loss of heterozygosity at Tp53 was detected in one case. Accordingly, none of the 29 patients with primary MDS nor the seven with disease progression in this study exhibited MSI. This shows that MSI may not be important in the pathogenesis or progression of MDS in contrast to other genetic mechanisms, notably recurrent chromosomal abnormalities that dysregulate the expression or function of genes controlling cell growth, differentiation and apoptosis.

The first case report of McLeod syndrome in a Chinese patient.

We report the first case of McLeod syndrome (MLS) in a 47-year-old Chinese man who presented with progressive limb weakness, chorea of feet, red blood cell acanthocytosis, absence of Kx red blood cell antigen and weak expression of Kell antigens. The diagnosis of MLS was confirmed by genetic testing showing a hemizygous mutation of XK gene. We review literature on neuroacanthocytosis in the Chinese population.

Genetic predisposition of white matter infarction with protein S deficiency and R355C mutation.

BACKGROUND: The association between protein S deficiency (PSD) and ischemic stroke is controversial and warrants further investigation. METHODS: We conducted a genotype and MRI correlation study in a Chinese family in which hereditary PSD cosegregated with premature ischemic strokes. Six out of 11 family members inherited PSD type III in an autosomal dominant manner. RESULTS: Among all PSD members, a novel missense mutation 1063C→T in exon 10 of protein S alpha (PROS1) was identified, which encoded a substitution of arginine to cysteine at position 355 (R355C) in the first globular domain of laminin A of protein S. Wild-type PROS1 sequences were retained in non-PSD members. MRI detected deep white matter infarctions predominantly distributed in the borderzone regions. The infarct topography was homogeneous in all adult mutant carriers. By contrast, cerebral infarction was absent in nonmutant carriers. Extensive investigation in the family did not reveal any confounding stroke risk. Haplotype analysis with high-density single nucleotide polymorphism markers revealed a 6.1-Mb minimally rearranged region (rs12494685 to rs1598240) in 3q11.2, lod = 3.0. Among the 7 annotated genes in this region, PROS1 is known to be associated with thrombotic disorders. MRI screening in an additional 10 PSD families without R355C showed no cerebral infarction. CONCLUSIONS: PROS1 R355C mutation cosegregated with PSD type III and premature white matter infarctions in the index family. The findings substantiate an association between PSD and stroke. Study of the mechanism underlying this association may improve our understanding of premature cryptogenic white matter infarction.