Association between minimum inhibitory concentration, beta-lactamase genes and mortality for patients treated with piperacillin/tazobactam or meropenem from the MERINO study

INTRODUCTION

This study aims to assess the association of piperacillin/tazobactam and meropenem minimum inhibitory concentration (MIC) and beta-lactam resistance genes with mortality in the MERINO trial.

METHODS

Blood culture isolates from enrolled patients were tested by broth microdilution and whole genome sequencing at a central laboratory. Multivariate logistic regression was performed to account for confounders. Absolute risk increase for 30-day mortality between treatment groups was calculated for the primary analysis (PA) and the microbiologic assessable (MA) populations.

RESULTS

320 isolates from 379 enrolled patients were available with susceptibility to piperacillin/tazobactam 94% and meropenem 100%. The piperacillin/tazobactam non-susceptible breakpoint (MIC > 16 mg/L) best predicted 30-day mortality after accounting for confounders (odds ratio 14.9, 95% CI 2.8 - 87.2). The absolute risk increase for 30-day mortality for patients treated with piperacillin/tazobactam compared with meropenem was 9% (95% CI 3% - 15%) and 8% (95% CI 2% - 15%) for the original PA population and the post-hoc MA populations, which reduced to 5% (95% CI -1% - 10%) after excluding strains with piperacillin/tazobactam MIC values > 16 mg/L. Isolates co-harboring ESBL and OXA-1 genes were associated with elevated piperacillin/tazobactam MICs and the highest risk increase in 30-mortality of 14% (95% CI 2% - 28%).

CONCLUSION

After excluding non-susceptible strains, the 30-day mortality difference was from the MERINO trial was less pronounced for piperacillin/tazobactam. Poor reliability in susceptibility testing performance for piperacillin/tazobactam and the high prevalence of OXA co-harboring ESBLs suggests meropenem remains the preferred choice for definitive treatment of ceftriaxone non-susceptible E. coli and Klebsiella.

International Society of Cardiovascular Infectious Diseases Guidelines for the Diagnosis, Treatment and Prevention of Disseminated Mycobacterium chimaera Infection Following Cardiac Surgery with Cardiopulmonary Bypass

Mycobacterial infection-related morbidity and mortality in patients following cardiopulmonary bypass surgery is high and there is a growing need for a consensus-based expert opinion to provide international guidance for diagnosing, preventing and treating in these patients. In this document the International Society for Cardiovascular Infectious Diseases (ISCVID) covers aspects of prevention (field of hospital epidemiology), clinical management (infectious disease specialists, cardiac surgeons, ophthalmologists, others), laboratory diagnostics (microbiologists, molecular diagnostics), device management (perfusionists, cardiac surgeons) and public health aspects.

Aiming for elimination: Outcomes of a consultation pathway supporting regional general practitioners to prescribe direct-acting antiviral therapy for hepatitis C

To increase access to treatment, the Australian government enabled general practitioners (GPs) to prescribe direct-acting antivirals (DAAs) to treat hepatitis C virus (HCV)-in consultation with a specialist if inexperienced in HCV management. This study describes the establishment and outcomes of a remote consultation pathway supporting GPs to treat HCV. Key stakeholders from primary and tertiary healthcare services in the Barwon South Western region developed and implemented an HCV remote consultation pathway. Pharmaceutical Benefits Schedule prescription data were used to evaluate GP DAA prescription 12 months pre-and post- pathway implementation. A retrospective review of patients referred for remote consultation for 12 months post- pathway inception was undertaken to determine the care cascade. HCV treatment initiation by GPs increased after implementation of the remote consultation pathway. In the 12-month study period, 74 GPs referred 169 people for remote consultation; 114 (67%) were approved for GP DAA treatment; 48 (28%) were referred for specialist assessment. In total, 119 (71%) patients commenced DAA; 69 were eligible for SVR12 assessment. Post-treatment HCV RNA data were available for 52 (75%) people; 37 achieved SVR12; 15 achieved SVR ranging from week 5 to 11 post-treatment. No treatment failure was detected. Collaborative development and implementation of a remote consultation pathway has engaged regional GPs in managing HCV. Follow-up post-treatment could be improved; however, no treatment failure has been documented. To eliminate HCV as a public health threat, it is vital that specialists support GPs to prescribe DAA.

Australasian Society of Infectious Diseases updated guidelines for the management of Clostridium difficile infection in adults and children in Australia and New Zealand

The incidence of Clostridium difficile infection (CDI) continues to rise, whilst treatment remains problematic due to recurrent, refractory and potentially severe nature of disease. The treatment of C. difficile is a challenge for community and hospital-based clinicians. With the advent of an expanding therapeutic arsenal against C. difficile since the last published Australasian guidelines, an update on CDI treatment recommendations for Australasian clinicians was required. On behalf of the Australasian Society of Infectious Diseases, we present the updated guidelines for the management of CDI in adults and children.

Survey of infection control and antimicrobial stewardship practices in Australian residential aged-care facilities

This study assessed infection prevention and antimicrobial stewardship (AMS) practices in Australian residential aged-care facilities (RACF). Two hundred and sixty-five surveys (15.6%) were completed with all states represented and the majority (177 (67.3%)) privately run. Only 30.6% RACF had infection control trained staff on site. Few facilities had AMS policies, only 14% had antimicrobial prescribing restrictions. Most facilities offered vaccination to residents (influenza vaccination rates >75% in 73% of facilities), but pneumococcal vaccination was poor.

Mucormycosis in Australia: contemporary epidemiology and outcomes

Mucormycosis is the second most common cause of invasive mould infection and causes disease in diverse hosts, including those who are immuno-competent. We conducted a multicentre retrospective study of proven and probable cases of mucormycosis diagnosed between 2004-2012 to determine the epidemiology and outcome determinants in Australia. Seventy-four cases were identified (63 proven, 11 probable). The majority (54.1%) were caused by Rhizopus spp. Patients who sustained trauma were more likely to have non-Rhizopus infections relative to patients without trauma (OR 9.0, p 0.001, 95% CI 2.1-42.8). Haematological malignancy (48.6%), chemotherapy (42.9%), corticosteroids (52.7%), diabetes mellitus (27%) and trauma (22.9%) were the most common co-morbidities or risk factors. Rheumatological/autoimmune disorders occurred in nine (12.1%) instances. Eight (10.8%) cases had no underlying co-morbidity and were more likely to have associated trauma (7/8; 87.5% versus 10/66; 15.2%; p <0.001). Disseminated infection was common (39.2%). Apophysomyces spp. and Saksenaea spp. caused infection in immuno-competent hosts, most frequently associated with trauma and affected sites other than lung and sinuses. The 180-day mortality was 56.7%. The strongest predictors of mortality were rheumatological/autoimmune disorder (OR = 24.0, p 0.038 95% CI 1.2-481.4), haematological malignancy (OR = 7.7, p 0.001, 95% CI 2.3-25.2) and admission to intensive care unit (OR = 4.2, p 0.02, 95% CI 1.3-13.8). Most deaths occurred within one month. Thereafter we observed divergence in survival between the haematological and non-haematological populations (p 0.006). The mortality of mucormycosis remains particularly high in the immuno-compromised host. Underlying rheumatological/autoimmune disorders are a previously under-appreciated risk for infection and poor outcome.

Consensus guidelines for implementation of quality processes to prevent invasive fungal disease and enhanced surveillance measures during hospital building works, 2014

Healthcare-associated fungal outbreaks impose a substantial economic burden on the health system and typically result in high patient morbidity and mortality, particularly in the immunocompromised host. As the population at risk of invasive fungal infection continues to grow due to the increased burden of cancer and related factors, the need for hospitals to employ preventative measures has become increasingly important. These guidelines outline the standard quality processes hospitals need to accommodate into everyday practice and at times of healthcare-associated outbreak, including the role of antifungal stewardship programmes and best practice environmental sampling. Specific recommendations are also provided to help guide the planning and implementation of quality processes and enhanced surveillance before, during and after high-risk activities, such as hospital building works. Areas in which information is still lacking and further research is required are also highlighted.

Candida infective endocarditis

Candida infective endocarditis (IE) is uncommon but often fatal. Most epidemiologic data are derived from small case series or case reports. This study was conducted to explore the epidemiology, treatment patterns, and outcomes of patients with Candida IE. We compared 33 Candida IE cases to 2,716 patients with non-fungal IE in the International Collaboration on Endocarditis-Prospective Cohort Study (ICE-PCS). Patients were enrolled and the data collected from June 2000 until August 2005. We noted that patients with Candida IE were more likely to have prosthetic valves (p < 0.001), short-term indwelling catheters (p < 0.0001), and have healthcare-associated infections (p < 0.001). The reasons for surgery differed between the two groups: myocardial abscess (46.7% vs. 22.2%, p = 0.026) and persistent positive blood cultures (33.3% vs. 9.9%, p = 0.003) were more common among those with Candida IE. Mortality at discharge was higher in patients with Candida IE (30.3%) when compared to non-fungal cases (17%, p = 0.046). Among Candida patients, mortality was similar in patients who received combination surgical and antifungal therapy versus antifungal therapy alone (33.3% vs. 27.8%, p = 0.26). New antifungal drugs, particularly echinocandins, were used frequently. These multi-center data suggest distinct epidemiologic features of Candida IE when compared to non-fungal cases. Indications for surgical intervention are different and mortality is increased. Newer antifungal treatment options are increasingly used. Large, multi-center studies are needed to help better define Candida IE.

Prevalence of multiresistant Gram-negative organisms in a surgical hospital in Ho Chi Minh Cit, Vietnam

OBJECTIVE

To determine resistance patterns of multiresistant Gram-negative organisms at a surgical hospital in Ho Chi Minh City, Vietnam, in order to guide appropriate antibiotic prescribing and improve infection control procedures.

METHOD

All samples sent in for microbiological analysis over a 3-month period were included. A resource neutral double disc-diffusion test was introduced to detect the presence of extended-spectrum beta-lactamase (ESBL) production.

RESULTS

We obtained 350 bacterial isolates from clinical specimens; 87.4% were Gram-negative bacteria (GNB). Of these, 88.9% were Enterobacteriaceae, of which 14.7% produced ESBL. Fifteen (37.5%) of these were isolated within 48 h of admission. Resistance to gentamicin and ciprofloxacin occurred in 70.0% and 72.5% of those organisms that produced ESBL and in 39.5% and 38.7% of those that did not. Resistance to third-generation cephalosporins was common: 36.7% of all GNB were resistant to ceftriaxone, 34.0% to cefotaxime, 19.6% to ceftazidime and 36.7% to cefoperazone.

CONCLUSION

Multiresistant Gram-negative organisms are common and pose a challenge to antibiotic therapy. Successful implementation of a simple test to detect ESBL production allowed reporting of these organisms, appropriate antibiotic prescribing and infection control interventions. Development of antibiotic-prescribing guidelines must take into account these resistance patterns.

Candida glabrata prosthetic valve endocarditis treated successfully with fluconazole plus caspofungin without surgery: a case report and literature review

Reported here is the case of a 72-year-old man who was diagnosed with Candida glabrata prosthetic mitral valve endocarditis and treated successfully with fluconazole plus caspofungin after he refused and was determined unfit for surgery. Initial treatment with intravenous amphotericin B resulted in acute renal impairment. Despite 8 days of intravenous fluconazole therapy, he remained fungemic. Caspofungin was added to the treatment regimen with subsequent sterilisation of blood culture. The patient was treated for 34 days with caspofungin and 41 days with fluconazole. He continued oral fluconazole after hospital discharge and remained well at follow-up 11 months later. The role of fluconazole and caspofungin in the treatment of Candida endocarditis is discussed.

Control of an outbreak of multi-drug-resistant Acinetobacter baumannii in an intensive care unit and a surgical ward

We describe an outbreak of multi-drug-resistant Acinetobacter baumannii (MRAB) that occurred in an intensive care unit (ICU) and a surgical ward from December 2003 to March 2004. Mapping patient movements on a timeline indicated that the outbreak was confined to these two areas. Investigation by the hospital's infection prevention service found that a possible source of spread was improper cleaning methods used on respiratory equipment. Pulsed-field gel electrophoresis analysis of available isolates indicated the presence of two distinct strains. One strain was seen in patients from the ICU and the other strain was seen in the surgical ward patients. Cleaning and environmental decontamination as well as staff education were implemented to halt further immediate spread. The deficiencies identified during the investigation were also resolved. The final outcome was the successful termination of this outbreak.

Acute cardiac allograft rejection in nitric oxide synthase-2(-/-) and nitric oxide synthase-2(+/+) mice: effects of cellular chimeras on myocardial inflammation and cardiomyocyte damage and apoptosis

BACKGROUND

The contribution of nitric oxide synthase (NOS)-2 to myocardial inflammation and cardiomyocyte necrosis and apoptosis during allograft rejection was investigated through heterotopic cardiac transplantation in mice.

METHODS AND RESULTS

In the first experiments, hearts from C3H donor mice were transplanted into NOS-2(-/-) and NOS-2(+/+) C57BL/6J.129J recipients. A second series of experiments included NOS-2(-/-) donor hearts transplanted into NOS-2(-/-) recipients and wild-type NOS-2(+/+) donor hearts transplanted into wild-type NOS-2(+/+) recipients. (All donors were C57BL/6J and recipients were C57BL/6J.129J.) In the first series of experiments, no significant differences were observed in allograft survival, rejection score, total number of apoptotic nuclei (TUNEL), total number of apoptotic cardiomyocytes, or graft NOS-2 mRNA and protein. Positive NOS-2 immunostaining occurred in endothelial cells and cardiomyocytes in the allografts; the inflammatory infiltrate was NOS-2 positive only when recipients were NOS-2(+/+). In the second series of experiments, cardiac allograft survival was significantly increased in the NOS-2(-/-) mice (26+/-13 versus 17+/-8 days, P<0.05), along with significant reductions in inflammatory infiltrate, rejection score, and total number of apoptotic nuclei (23.5+/-9.5 versus 56.4+/-15.3, P<0.01) and of apoptotic cardiomyocytes (2.9+/-1.6 versus 6.9+/-2.7, P<0.05). No NOS-2 or nitrotyrosine, a marker of peroxynitrite exposure, was detected in NOS-2(-/-) allografts transplanted into NOS-2(-/-) recipients.

CONCLUSIONS

The data suggest that NO derived from NOS-2 contributes to the inflammatory response and to cardiomyocyte damage and apoptosis during acute cardiac allograft rejection.

Effectiveness of short-course quinine and single-dose sulfadoxine-pyrimethamine in the treatment of Plasmodium falciparum malaria in Mpumalanga Province, South Africa

INTRODUCTION

Quinine therapy for 7 days remains the mainstay for treating hospitalised malaria cases in South Africa. However, limited resources, including available beds and staff, often result in early discharge of non-severe cases, with quinine tablets for outpatient use. The effectiveness of shorter course quinine therapy coupled with a long-acting antimalarial drug has never been established in Africa, in particular in a population without malaria immunity.

METHODS

A study was conducted to evaluate the effectiveness of a 3-day course of therapy with quinine sulphate (10 mg/kg 8-hourly) followed by a single dose of sulfadoxine-pyrimethamine (SP) according to weight category, before discharge, for 133 hospitalised patients with uncomplicated Plasmodium falciparum malaria at Shongwe Hospital, Mpumalanga province, between February and July 1998. Study endpoints included clinical recovery and parasitological cure, including polymerase chain reaction (PCR) 42 days after initiating treatment.

RESULTS

One hundred and thirty of 131 patients (99%) successfully followed up for 42 days demonstrated clinical and parasitological cure. The remaining patient, who had evidence of a recrudescent infection on PCR, was 1 of 61 patients who were still parasitaemic on discharge from hospital.

CONCLUSION

The abbreviated course of quinine therapy coupled with a single dose of SP for the treatment of non-severe hospitalised cases of P. falciparum malaria, in an area with demonstrated low levels of SP resistance, was highly effective. This approach has potential benefits, including reduced duration of hospitalisation, fewer quinine-associated adverse events and protection against the evolution of quinine resistance by limiting unsupervised quinine therapy in the community. It may, however, be prudent to document a negative blood film before discharge from hospital.

Upregulation of COX-2 during cardiac allograft rejection

BACKGROUND

The hypothesis that cyclooxygenase-2 (COX-2) is involved in the myocardial inflammatory response during cardiac allograft rejection was investigated using a rat heterotopic abdominal cardiac transplantation model.

METHODS AND RESULTS

COX-2 mRNA and protein in the myocardium of rejecting cardiac allografts were significantly elevated 3 to 5 days after transplantation compared with syngeneic controls (n=3, P<0.05). COX-2 upregulation paralleled in time and extent the upregulation of iNOS mRNA, protein, and enzyme activity in this model. COX-2 immunostaining was prominent in macrophages infiltrating the rejecting allografts and in damaged cardiac myocytes. Prostaglandin (PG) levels in rejecting allografts were also higher than in native hearts. Because NO has been reported to modulate PG synthesis by COX-2, additional transplants were performed using animals treated with a selective COX-2 inhibitor (SC-58125) and a selective inhibitor of the inducible nitric oxide synthase (iNOS) N-aminomethyl-L-lysine. At posttransplant day 5, inhibitor administration resulted in a significant reduction of COX-2 mRNA expression (3764+/-337 versus 5110+/-141 arbitrary units, n=3, P<0.05) and iNOS enzymatic activity (1.7+/-0.4 versus 22.8+/-14. 4 nmol/mg protein, n=3, P<0.01) compared with vehicle-treated allogeneic transplants. Allograft survival in treated animals was increased modestly from 5.4 to 6.4 days (P<0.05). However, apoptosis of cardiac myocytes (TUNNEL method) was only marginally reduced relative to vehicle controls in treated graft recipients. The intensity of allograft rejection was also similar in the treated and untreated allografts.

CONCLUSIONS

The data indicates that COX-2 expression is enhanced in parallel with iNOS in the myocardium during cardiac allograft rejection.

Anaerobic meningitis due to Peptostreptococcus species: case report and review

We describe a patient with postsurgical anaerobic meningitis due to Peptostreptococcus magnus. In cases of meningitis associated with Peptostreptococcus species reported in the literature, the most common predisposing factors are meningorectal fistulae and head-and-neck surgery. Most patients respond well to appropriate antimicrobial therapy. Surgical intervention may be required in some instances.

Apoptosis of cardiac myocytes during cardiac allograft rejection. Relation to induction of nitric oxide synthase

BACKGROUND

Apoptosis is a distinct form of programmed cell death characterized by activation of endonucleases that cleave nuclear DNA, condensation and fragmentation of nuclear chromatin, blebbing of intact membranes, and cell shrinkage and fragmentation. The mechanisms responsible are unclear, but nitric oxide (NO) generated by inducible NO synthase (iNOS) has been demonstrated to induce apoptosis in macrophages in vitro. This study investigated whether apoptosis occurs during cardiac allograft rejection and examined the relationship of apoptosis to iNOS expression.

METHODS AND RESULTS

Heterotopic abdominal transplantation from Lewis to Wistar-Furth rats was used as a model of cardiac allograft rejection; Lewis-to-Lewis grafts served as controls. Apoptosis was identified by DNA ladders after electrophoresis on agarose gels and by in situ labeling of DNA fragments; cell types were determined by immunohistochemistry. The number of apoptotic cardiac myocytes increased sharply from day 3 (0.31/mm2 ventricular tissue) to day 5 (1.27/mm2) after transplantation. At day 5, allografts showed a significant increase (P < .01) in apoptotic cardiac myocytes, macrophages, and endothelial cells compared with syngeneic grafts. The expression of iNOS mRNA, protein, and enzyme activity paralleled in time and extent the apoptosis of cardiac myocytes. iNOS immunostaining of infiltrating macrophages and cardiac muscle fibers increased significantly in the allografts at days 3 to 5 and was accompanied by immunostaining of both cell types for nitrotyrosine, which is indicative of peroxynitrite formation.

CONCLUSIONS

Apoptosis of myocardial cells occurs during cardiac allograft rejection. Apoptosis during rejection parallels the expression of iNOS, which suggests that apoptosis may be triggered by NO and peroxynitrite.

Fludarabine phosphate: A DNA synthesis inhibitor with potent immunosuppressive activity and minimal clinical toxicity

Fludarabine phosphate selectively eliminates normal and malignant mononuclear cells in large animals and man through the inhibition of DNA synthesis. The drug depletes mononuclear cells from culture within 24 hours of initial exposure, CD4 and CD8 T cells being more sensitive than either CD20 B cells or CD34 bone marrow precursors. Mitogenic activation of lymphocytes enhances cellular elimination from culture. Fludarabine inhibits PHA-induced T-cell proliferation by >90 per cent and mixed lymphocyte reactions (allogeneic and xenogeneic) by >95 per cent. Fludarabine exerts its cytolytic effects through the induction of endonuclease-independent apoptosis. A 5-day course of fludarabine (50 mg/m2 intravenously once daily) induces both T- and B-cell lymphopenia in Cynomolgus monkeys and Papio baboons. Transient neutropenia was the only side-effect seen in experimental animals. Pretreatment of Cynomolgus monkeys with this regimen of fludarabine causes a prolongation of ABO-compatible skin allograft survival from 8 days (control) to 16 days (drug treated group). Secondary allotransplantation into presensitized recipients showed a similar prolongation of graft survival with fludarabine pretreatment (8 days vs 5 days control). Fludarabine promises to be a potent immunosuppressive agent with low clinical toxicity.

Use of gene therapy to induce human-mouse xenogeneic chimerism

BACKGROUND

Bone marrow transplantation (BMT) has been used in the laboratory to overcome the immunologic barriers to xenotransplantation and results in chimerism and specific tolerance to donor antigens in lethally irradiated mice. Clinically, BMT carries the considerable risks of graft-versus-host disease and graft failure. Retrovirus-mediated gene transfer could provide a means of introducing foreign major histocompatibility (MHC) genes into host bone marrow cells (BMC) and thus accomplish the immunologic goals of BMT, without the associated risks.

METHODS

Using a Moloney virus-based vector, a replication defective retrovirus was constructed that contained a complementary DNA encoding the human MHC antigen HLA-A2. Three million C57BL/6 mouse BMC were cocultured for 48 hours with 1 x 10(6) HLA-A2 virus "producer" cells in the presence of 15% WEHI supernatant (interleukin-3) and 200 units/ml interleukin-6. Putatively infected BMC were then used at 2 to 3 x 10(6) BMC/animal to reconstitute lethally irradiated syngeneic mice.

RESULTS

Twelve days after reconstitution, spleen colonies were found to have integrated the full-length retroviral sequences. Thirty days after BMT, the introduced DNA could be found in the bone marrow, thymus, and spleen, and approximately 5% of T cells in the spleen expressed the HLA-A2 surface antigen.

CONCLUSIONS

These data show that xenogeneic MHC genes can be introduced and expressed in mouse hematopoietic cells in vivo and indicate that gene therapy potentially may be used in the future to manipulate the immune system to induce transplantation tolerance.

T-cell chronic lymphocytic leukemia. Unusual morphologic, phenotypic, and karyotypic features in association with light chain amyloidosis

BACKGROUND

Lymphocytes that display a phenotype of mature B-cells, T-cells, natural killer (NK) cells, or a combination of T-cells and NK cells can be found in patients with lymphoproliferations that manifest as expansions of peripheral blood lymphocytes (PBL). If these PBL expansions exhibit clonality, they can be classified as chronic lymphocytic leukemia (CLL).

METHODS/RESULTS

A patient who had two simultaneous, clonal lymphoproliferative disorders manifested as an unusual T-cell CLL in conjunction with systemic light chain amyloidosis is described. Gene rearrangement studies of the PBL of the patient showed clonal rearrangements of both the T-cell receptor beta (T beta) chain and the immunoglobulin genes. Additional immunologic and microscopic studies of the T-cells of the patient showed that they were large, agranular, CD4+ T-cells that also expressed the NK cell marker CD57. Cytogenetics disclosed an unusual karyotype in the PBL.

CONCLUSIONS

The pathogenesis of this T-cell CLL and whether it truly represents a malignant disorder, as well as its relation to amyloidosis, is discussed.

The bcl-2 gene translocation is undetectable in Hodgkin's disease by Southern blot hybridization and polymerase chain reaction

B-cell associated antigens are frequently expressed by the Reed-Sternberg (RS) cells of lymphocyte predominance (LP) Hodgkin's disease (HD) and are sometimes expressed by those of nodular sclerosis (NS) and mixed cellularity (MC) HD. Clonal immunoglobulin gene rearrangements have been detected in some HD cases as well. These findings suggest that at least some cases of HD may be of B-cell derivation. Rearrangements of the bcl-2 gene, associated with the t(14;18)(q32;q21) are present in more than 75% of follicular and 30% of diffuse lymphomas of B-cell origin, suggesting that this translocation plays an important role in B-cell lymphomagenesis. In this study, we investigated 34 cases of HD (10 LP, 14 NS, and 10 MC) for bcl-2 gene rearrangements to determine if this B-cell lymphoma-associated translocation also plays a role in the pathogenesis of HD. The cases of HD were analyzed by Southern blot hybridization, using DNA probes that detect the major and minor breakpoint cluster regions and a 5'bcl-2 breakpoint region recently cloned and found to be involved in B-cell chronic lymphocytic leukemia, and by the polymerase chain reaction (PCR), using oligonucleotides capable of amplifying and detecting the major breakpoint region (mbr) and minor cluster region (mcr) breakpoint regions in t(14;18). bcl-2 translocations were not detected in any of the 34 cases of HD by Southern blot hybridization or by PCR. This is in spite of the fact that RS cells expressing B-cell-associated antigen CD20 were detectable in 7/8 cases of LP HD and 6/24 cases of NS and MC HD with monoclonal antibody L26. Therefore, these results indicate that the bcl-2 gene translocation does not play an important role in the pathogenesis of HD and did not provide evidence for the B-cell origin of HD.

Detection and characterization of human T-cell lymphotropic virus type I (HTLV-I) associated T-cell neoplasms in an HTLV-I nonendemic region by polymerase chain reaction

Human T-cell lymphotropic virus type I (HTLV-I) associated adult T-cell leukemia/lymphoma (ATLL) occurs endemically in southwestern Japan, the Caribbean, and West Africa, but occurs sporadically in most of the rest of the world. However, because ATLL and non-HTLV-I associated T-cell neoplasms share overlapping clinicopathologic features, the prevalence of ATLL in nonendemic regions is unknown. In this study, 75 T-cell neoplasms randomly procured from the metropolitan New York City area were examined by polymerase chain reaction (PCR) for the presence of integrated HTLV-I proviral sequences. HTLV-I genomic sequences were detected by PCR in 6 of the 75 cases (8%); this result was confirmed by Southern blot hybridization. The clinicopathologic features of the HTLV-I positive and HTLV-I negative T-cell neoplasms were then compared. Although the clinicopathologic features of patients from these two groups overlapped, some findings were more commonly associated with HTLV-I positive neoplasms. Five of the six patients with HTLV-I positive neoplasms were from HTLV-I endemic areas, five were black, five were women, and five were less than 45 years of age, while the majority of the patients with HTLV-I negative T-cell malignancies were elderly white men. The incidence of hypercalcemia and lytic bone lesions was significantly more common among patients with HTLV-I positive T-cell neoplasms (P less than .001 and P = .004, respectively). The immunophenotypes of the HTLV-I positive and negative tumors were similar; however, all HTLV-I positive neoplasms were CD7 negative (P less than .001). In summary, our findings: (1) demonstrate the special clinicopathologic and immunophenotypic features of HTLV-I positive T-cell neoplasms, (2) suggest that most of the rare cases of HTLV-I-associated T-cell neoplasms occurring in HTLV-I nonendemic areas are actually endemic cases; and (3) that PCR is a sensitive, clinically useful technique for identifying HTLV-I associated T-cell neoplasms.

bcl-1 rearrangement. Frequency and clinical significance among B-cell chronic lymphocytic leukemias and non-Hodgkin's lymphomas

The authors investigated the structural organization of the bcl-1 locus, a putative oncogene associated with reciprocal chromosomal translocation t(11;14), by Southern blot hybridization analysis and its frequency, distribution, and prognostic significance in a panel of 156 clinically and pathologically well-defined B-cell chronic lymphocytic leukemias (CLLs) and non-Hodgkin's lymphomas (NHLs). The authors detected bcl-1 rearrangements in only 2 of 42 CLLs and 4 of 114 NHLs, specifically 3 of 29 diffuse small lymphocytic and 1 of 10 diffuse small cleaved cell and none of 5 diffuse intermediate lymphocytic, 13 follicular predominantly small cleaved, 17 follicular mixed small cleaved and large cell, 4 diffuse mixed small and large cell, 26 diffuse large cell, and 10 diffuse small noncleaved cell lymphomas. None of seven cases of Rai stage III or IV CLL or seven diffuse large cell lymphomas occurring as Richter's syndrome exhibited bcl-1 rearrangements. In conclusion, the bcl-1 locus rearranges in only about 4% of B-cell CLLs and NHLs, is predominantly rearranged in low-grade B-cell neoplasms, and does not appear to be preferentially associated with those occasional CLLs and low-grade NHLs displaying clinical aggressiveness, advanced clinical stage, or large cell transformation (Richter's syndrome). Therefore the demonstration of bcl-1 rearrangement does not appear to have clinically useful prognostic significance.

Extranodal noncutaneous lymphoid hyperplasias represent a continuous spectrum of B-cell neoplasia: demonstration by molecular genetic analysis

We investigated 16 lymphoid proliferations occurring in the ocular adnexa, salivary glands, breast, and thyroid gland and satisfying the histopathologic and immunophenotypic criteria of benign lymphoid hyperplasia for the presence of clonal rearrangements of the antigen receptor, c-myc, bcl-1, and bcl-2 genes and Epstein-Barr virus (EBV) DNA sequences. Each of these 16 extranodal, noncutaneous lymphoid neoplasms exhibited clonal immunoglobulin heavy and/or light chain and lacked T-cell receptor (TCR) beta-chain gene rearrangements. The patterns of immunoglobulin gene rearrangements included solitary and multiple barely perceptible to faint bands, solitary clear and definite bands, and solitary high-intensity bands superimposed on a background of multiple less-intense bands. Three ocular adnexal lymphoid neoplasms exhibited bcl-1 or bcl-2 gene rearrangements. None of the 16 lymphoid neoplasms contained EBV DNA sequences. Two patients developed a histopathologically confirmed malignant lymphoma in an extranodal site. None of the remaining 14 patients developed additional lymphoid neoplasms during a mean follow-up period of 30 months, despite conservative therapy. These results demonstrate that extranodal, noncutaneous lymphoid neoplasms meeting the histopathologic and immunophenotypic criteria for benign lymphoid hyperplasia frequently contain occult monoclonal and oligoclonal B-cell populations representing a continuous and progressive spectrum of B-cell neoplasia up to and including malignant lymphoma.

Isolation of a replication-defective murine leukaemia virus from cultured AKR leukaemia cells

Mice of the AKR strain are characterised by a high incidence of spontaneous thymic lymphomas. AKR chromosomes contain the genomes of ecotropic murine leukaemia virus (MuLV) at two loci, termed Akv-1 and Akv-2 (refs 2-6). Shortly after birth, the normal tissues of AKR mice begin to produce high levels of this XC-positive MuLV (ref. 7) (that is, one that forms XC plaques). A second class of MuLV, termed mink cell focus-inducing virus (MCF), is produced specifically by preleukaemic and leukaemic AKR thymocytes. Nowinski et al. have established a series of tissue culture lines from AKR leukaemias and reported that the resulting cell lines produce virus particles, but that these particles, surprisingly, do not give rise to XC plaques. We have analysed the virus particles produced by one of these cell lines, termed AKRSL2. We show here that, unlike most or all of the nonmalignant tissues in the AKR mouse, these cultured lymphoma cells produce very little non-defective ecotropic MuLV; however, they do produce replication-defective ecotropic MuLV.

Characterization of clones derived from an attenuated strain of Rauscher murine leukaemia virus

With a view to defining its subpopulations, an attenuated strain of Rauscher leukaemia virus, which comprises a majority of fragile virions, was closed by end-point dilution. The presence in the obtained clones of markers (analyzed by radioimmunoassay and isoelectric focusing) associated with Rauscher virus, together with persistent infectivity and leukaemogenicity, excluded the hypothesis that endogenous virus might have replaced the original Rauscher population. Due to the closing method employed, non fragile virions were obtained. Moreover, despite its selectivity for the lymphatic leukaemia virus component, sporadic cases of atypical erythroblastogenic leukaemia were observed.

Fragility of attenuated Rauscher leukemia virus

Some biochemical properties of virulent (RRL+) and attenuated (RCL-) Rauscher leukemia virus were compared. It was shown that the reverse transcriptase (RT) activity of 'aged' as well as 'fresh' RCL- virions was 25--30% of that found for RRL+. The thermal sensitivity of the RT was the same for both viruses. A 60--70S RNA could be extracted from 'aged' RRL+, while no high molecular weight RNA was obtained from 'aged' RCL-. After centrifuging in sucrose gradient, most of the RT activity and 3H-labeled RNA of 'aged' RRL+ was recovered at 1.14--1.16 g/cm3, while for 'aged' RCL- no labeled RNA, and at most 10% of the original RT activity were found in the same zone. The fragility seemed to increase in the course of aging, since 'fresh' RCL- banded at 1.14--1.16 g/cm3 as did 'fresh' RRL+. Also, 3H-labeled viral RNA was found in the viral bands, from which 60--70S RNA could be extracted. Molecular hybridizations showed that 20% of the nucleic acid sequences related to Rauscher leukemia virus found in the RNA of RRL+-infected cells were missing in the RNA of RCL--infected cells.