Functional Involvement of circRNAs in the Innate Immune Responses to Viral Infection

Effective viral clearance requires fine-tuned immune responses to minimize undesirable inflammatory responses. Circular RNAs (circRNAs) are a class of non-coding RNAs that are abundant and highly stable, formed by backsplicing pre-mRNAs, and expressed ubiquitously in eukaryotic cells, emerging as critical regulators of a plethora of signaling pathways. Recent progress in high-throughput sequencing has enabled a better understanding of the physiological and pathophysiological functions of circRNAs, overcoming the obstacle of the sequence overlap between circRNAs and their linear cognate mRNAs. Some viruses also encode circRNAs implicated in viral replication or disease progression. There is increasing evidence that viral infections dysregulate circRNA expression and that the altered expression of circRNAs is critical in regulating viral infection and replication. circRNAs were shown to regulate gene expression via microRNA and protein sponging or via encoding small polypeptides. Recent studies have also highlighted the potential role of circRNAs as promising diagnostic and prognostic biomarkers, RNA vaccines and antiviral therapy candidates due to their higher stability and lower immunogenicity. This review presents an up-to-date summary of the mechanistic involvement of circRNAs in innate immunity against viral infections, the current understanding of their regulatory roles, and the suggested applications.

Phenotypic detection of methicillin resistance, biofilm production, and inducible clindamycin resistance in Staphylococcus aureus clinical isolates in Kathmandu, Nepal

INTRODUCTION

Methicillin resistance, inducible clindamycin resistance (ICR), biofilm production, and increased minimum inhibitory concentration (MIC) of vancomycin in Staphylococcus aureus are major causes of antibiotic treatment failure and increased morbidity and mortality. The surveillance of such isolates and the study of their antimicrobial pattern are essential in managing the infections caused by these isolates. This study aimed to determine methicillin resistance, biofilm production, and ICR in S. aureus isolates from a tertiary care hospital in Kathmandu, Nepal.

MATERIALS AND METHODS

A total of 217 S. aureus isolated from different samples were processed following standard laboratory procedures. Antibiotic susceptibility testing was performed by the Kirby-Bauer disk diffusion technique. Methicillin-resistant S. aureus (MRSA) were identified by the cefoxitin disk diffusion test, and biofilm producers were examined using the microtiter plate technique. D-test and E-test were performed to determine inducible clindamycin resistance and minimum inhibitory concentration of vancomycin, respectively.

RESULTS

Among the 217 S. aureus isolates, 78.3% were multidrug-resistant (MDR), 47.0% were MRSA, 62.2% were biofilm producers, and 50.7% showed ICR. All MRSA isolates exhibited MIC levels of vancomycin within the susceptible range. Biofilm producers and MRSA isolates showed elevated antimicrobial resistance. MRSA was significantly associated with MDR. Biofilm-producing and multidrug-resistant MRSA isolates showed significantly higher MIC levels of vancomycin (p = 0.0013 and < 0.0001, respectively), while ICR was significantly higher in MDR (p = 0.0001) isolates.

CONCLUSION

High multidrug resistance, MRSA, and ICR in this study call for routine evaluation of antibiotic susceptibility patterns of S. aureus. Vancomycin can be used to treat serious staphylococcal infections. Clindamycin should be prescribed only after performing the D-test. Drugs like teicoplanin, chloramphenicol, doxycycline, amikacin, and levofloxacin can treat MRSA infections.

Initial activation of STAT2 induced by IAV infection is critical for innate antiviral immunity

STAT2 is an important transcription factor activated by interferons (IFNs) upon viral infection and plays a key role in antiviral responses. Interestingly, here we found that phosphorylation of STAT2 could be induced by several viruses at early infection stage, including influenza A virus (IAV), and such initial activation of STAT2 was independent of type I IFNs and JAK kinases. Furthermore, it was observed that the early activation of STAT2 during viral infection was mainly regulated by the RIG-I/MAVS-dependent pathway. Disruption of STAT2 phosphorylation at Tyr690 restrained antiviral response, as silencing STAT2 or blocking STAT2 Y690 phosphorylation suppressed the expression of several interferon-stimulated genes (ISGs), thereby facilitating viral replication. In vitro experiments using overexpression system or kinase inhibitors showed that several kinases including MAPK12 and Syk were involved in regulation of the early phosphorylation of STAT2 triggered by IAV infection. Moreover, when MAPK12 kinase was inhibited, expression of several ISGs was clearly decreased in cells infected with IAV at the early infection stage. Accordingly, inhibition of MAPK12 accelerated the replication of influenza virus in host. These results provide a better understanding of how initial activation of STAT2 and the early antiviral responses are induced by the viral infection.

Diagnostic performance of GeneXpert MTB/RIF in detecting MTB in smear-negative presumptive TB patients

BACKGROUND

Tuberculosis (TB) is a leading cause of morbidity and mortality worldwide. Control of TB is lingering by the lack of diagnostic tests that are simple, rapid, yet accurate. Thus, smear-negative pulmonary TB often misses the diagnosis. The study evaluated the performance of GeneXpert MTB/RIF assay for the detection of Mycobacterium tuberculosis (MTB).

METHODS

The study was carried out from June to December 2016 in Nepal Tuberculosis Center, Bhaktapur, Nepal. A total of 173 sputum samples were collected and processed by microscopy [Auramine-O staining and Ziehl-Neelsen (ZN) staining], followed by GeneXpert MTB/RIF assay and culture in Lowenstein-Jensen (LJ) medium.

RESULTS

Of 173 sputum samples, 162 (93.6%) were smear-negative. Of 162 smear-negative sputum samples, 35 (21.6%) were confirmed to have MTB by culture, and 31 (19.1%) by GeneXpert MTB/RIF assay. Of 31 GeneXpert-positive samples, 25 (80.6%) were susceptible, 4 (12.9%) were resistant, and 2 (6.45%) were intermediate to rifampicin. The sensitivity, specificity, positive predictive value, and negative predictive value of GeneXpert MTB/RIF assay for smear-negative sputum samples were 74.3%, 96.6%, 86.7%, and 92%, respectively. The GeneXpert MTB/RIF has a substantial diagnostic agreement of 90.91% with culture (Cohen's Kappa coefficient = 0.73).

CONCLUSION

The diagnostic performance of GeneXpert MTB/RIF assay was almost on par with culture, and thus can be relied upon for MTB detection in smear-negative sputum samples.

sRNA23, a novel small RNA, regulates to the pathogenesis of Streptococcus suis serotype 2

ABBREVIATION

sRNA: small noncoding RNA; FBA: fructose diphosphate aldolase; rplB: 50S ribosomal protein L2; RACE: rapid amplification of cDNA ends; EMSA: electrophoretic mobility shift assay; THB: Todd-Hewitt broth; FBS: fetal bovine serum; BIP: 2,2'-Bipyridine.

Deficiency of eIF4B Increases Mouse Mortality and Impairs Antiviral Immunity

Eukaryotic translation initiation factor 4B (eIF4B) plays an important role in mRNA translation initiation, cell survival and proliferation in vitro. However, its function in vivo is poorly understood. Here, we identified that eIF4B knockout (KO) in mice led to embryonic lethality, and the embryos displayed severe liver damage. Conditional KO (CKO) of eIF4B in adulthood profoundly increased the mortality of mice, characterized by severe pathological changes in several organs and reduced number of peripheral blood lymphocytes. Strikingly, eIF4B CKO mice were highly susceptible to viral infection with severe pulmonary inflammation. Selective deletion of eIF4B in lung epithelium also markedly promoted replication of influenza A virus (IAV) in the lung of infected animals. Furthermore, we observed that eIF4B deficiency significantly enhanced the expression of several important inflammation-associated factors and chemokines, including serum amyloid A1 (Saa1), Marco, Cxcr1, Ccl6, Ccl8, Ccl20, Cxcl2, Cxcl17 that are implicated in recruitment and activation of neutrophiles and macrophages. Moreover, the eIF4B-deficient mice exhibited impaired natural killer (NK) cell-mediated cytotoxicity during the IAV infection. Collectively, the results reveal that eIF4B is essential for mouse survival and host antiviral responses, and establish previously uncharacterized roles for eIF4B in regulating normal animal development and antiviral immunity in vivo.

Prevalence of multidrug-resistance and bla VIM and bla IMP genes among gram-negative clinical isolates in tertiary care hospital, Kathmandu, Nepal

Background and Objectives

Carbapenems have been the choice of antibiotics for the treatment of infections caused by multidrug-resistant bacteria. The main objective of this study was to determine the prevalence of carbapenemase (bla _VIM and bla _IMP ) producing isolates among Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii.

Materials and Methods

A total of 1,151 clinical samples were collected from the patients visiting Annapurna Neurological Institute and Allied Science and Annapurna Research Centre, Kathmandu, between June 2017 and January 2018. Antibiotic susceptibility testing (AST) was performed on the Enterobacteriaceae, P. aeruginosa and A. baumannii isolates using the Kirby-Bauer disk diffusion method. The modified Hodge test (MHT) was performed on the carbapenem-resistant isolates to confirm carbapenemase production. DNA was extracted and then screened for bla _VIM and bla _IMP genes by multiplex PCR.

Results

Of the total 1,151 clinical samples, 253 (22.0%) showed positive growth. Of them, 226 (89.3%) were identified as Enterobacteriaceae, P. aeruginosa, and A. baumannii. Among the 226 isolates, 106 (46.9%) were multidrug-resistant. Out of the 106, 97 (91.5%) isolates showed resistance to at least one of the carbapenem used. Among the 97 carbapenem-resistant isolates, 67 (69.1%) showed the modified Hodge test (MHT) positive results. bla _VIM and bla _IMP were detected in 40 and 38 isolates respectively using multiplex PCR assay.

Conclusion

This study determined a high prevalence of MDR and carbapenem resistance among Enterobacteriaceae, P. aeruginosa, and A. baumannii as detected by the presence of bla _VIM and bla _IMP genes. This study recommends the use of rapid and advanced diagnostic tools along with conventional phenotypic detection methods in the clinical settings for early detection and management of drug-resistant pathogens to improve treatment strategies.

Acute Infection of Viral Pathogens and Their Innate Immune Escape

Viral infections can cause rampant disease in human beings, ranging from mild to acute, that can often be fatal unless resolved. An acute viral infection is characterized by sudden or rapid onset of disease, which can be resolved quickly by robust innate immune responses exerted by the host or, instead, may kill the host. Immediately after viral infection, elements of innate immunity, such as physical barriers, various phagocytic cells, group of cytokines, interferons (IFNs), and IFN-stimulated genes, provide the first line of defense for viral clearance. Innate immunity not only plays a critical role in rapid viral clearance but can also lead to disease progression through immune-mediated host tissue injury. Although elements of antiviral innate immunity are armed to counter the viral invasion, viruses have evolved various strategies to escape host immune surveillance to establish successful infections. Understanding complex mechanisms underlying the interaction between viruses and host’s innate immune system would help develop rational treatment strategies for acute viral infectious diseases. In this review, we discuss the pathogenesis of acute infections caused by viral pathogens and highlight broad immune escape strategies exhibited by viruses.

RDUR, a lncRNA, Promotes Innate Antiviral Responses and Provides Feedback Control of NF-κB Activation

Influenza A virus (IAV), a highly infectious respiratory pathogen, remains a major threat to global public health. Numerous long non-coding RNAs (lncRNAs) have been shown to be implicated in various cellular processes. Here, we identified a new lncRNA termed RIG-I-dependent IAV-upregulated noncoding RNA (RDUR), which was induced by infections with IAV and several other viruses. Both in vitro and in vivo studies revealed that robust expression of host RDUR induced by IAV was dependent on the RIG-I/NF-κB pathway. Overexpression of RDUR suppressed IAV replication and downregulation of RDUR promoted the virus replication. Deficiency of mouse RDUR increased virus production in lungs, body weight loss, acute organ damage and consequently reduced survival rates of mice, in response to IAV infection. RDUR impaired the viral replication by upregulating the expression of several vital antiviral molecules including interferons (IFNs) and interferon-stimulated genes (ISGs). Further study showed that RDUR interacted with ILF2 and ILF3 that were required for the efficient expression of some ISGs such as IFITM3 and MX1. On the other hand, we found that while NF-κB positively regulated the expression of RDUR, increased expression of RDUR, in turn, inactivated NF-κB through a negative feedback mechanism to suppress excessive inflammatory response to viral infection. Together, the results demonstrate that RDUR is an important lncRNA acting as a critical regulator of innate immunity against the viral infection.

Prevalence of multidrug-resistant and extended-spectrum beta-lactamase producing Gram-negative isolates from clinical samples in a tertiary care hospital of Nepal

BACKGROUND

The existence of multidrug-resistant organisms, including extended-spectrum beta-lactamases (ESBLs), is on rise across the globe and is becoming a severe problem. Knowledge of the prevalence and antibiogram profile of such isolates is essential to develop an appropriate treatment methodology. This study aimed to study the prevalence of Gram-negative isolates exhibiting ESBL at a tertiary care hospital and study their antibiogram profile.

METHODS

A cross-sectional study was conducted at Shahid Gangalal National Heart Centre, Kathmandu, Nepal, from June 2018 to November 2018. A total of 770 clinical samples were collected and identified using the conventional biochemical tests following the Clinical and Laboratory Standard Institute (CLSI) guidelines. Antimicrobial susceptibility testing (AST) was performed using the standardized Kirby-Bauer disk diffusion method. The screening test for ESBL producers was performed as recommended by the CLSI and the confirmatory test was performed phenotypically using the E-test.

RESULTS

Out of the 92 isolates, 84 (91.3%) were multidrug-resistant, and 47 (51.1%) were found to be potential ESBL producers. Of these, 16 isolates were confirmed ESBL producers by the E-test. Escherichia coli and Klebsiella pneumoniae were the predominant isolates and were also the major ESBL producers. Besides polymyxin B (100% sensitive), meropenem and imipenem showed high efficacy against the ESBL producers.

CONCLUSION

Multidrug resistance was very high; however, ESBL production was low. Polymyxin B and carbapenems are the choice of drugs against ESBL producers but should be used only as the last line drugs.

Robust expression of p27Kip1 induced by viral infection is critical for antiviral innate immunity

Influenza A virus (IAV) infection regulates the expression of numerous host genes. However, the precise mechanism underlying implication of these genes in IAV pathogenesis remains largely unknown. Here, we employed isobaric tags for relative and absolute quantification (iTRAQ) to identify host proteins regulated by IAV infection. iTRAQ analysis of mouse lungs infected or uninfected with IAV showed a total of 167 differentially upregulated proteins in response to the viral infection. Interestingly, we observed that p27Kip1, a potent cyclin-dependent kinase inhibitor, was markedly induced by IAV both at mRNA and protein levels through in vitro and in vivo studies. Furthermore, it was shown that innate immune signalling positively regulated p27Kip1 expression in response to IAV infection. Ectopic expression of p27Kip1 in A549 cells dramatically inhibited IAV replication, whereas, p27Kip1 knockdown significantly enhanced the virus replication. in vivo experiments demonstrated that p27Kip1 knockout (KO) mice were more susceptible to IAV than wild-type (WT) mice: exhibiting higher viral load in lung tissue, faster body-weight loss, reduced survival rate and more severe organ damage. Moreover, we found that p27Kip1 overexpression facilitated the degradation of viral NS1 protein, caused a dramatic STAT1 activation and promoted the expression of IFN-β and several critical antiviral interferon-stimulated genes (ISGs). Increased p27Kip1 expression also restricted infections of several other viruses. Conversely, IAV-infected p27Kip1 KO mice exhibited a sharp increase in NS1 protein accumulation, reduced level of STAT1 activation and decreased expression of IFN-β and the ISGs in the lung compared to WT animals. These findings reveal a key role of p27Kip1 in enhancing antiviral innate immunity.

Intestinal Parasitic Infections among Prison Inmates in Kathmandu Nepal

BACKGROUND

Prison inmates are at high risk of intestinal parasitic infections. Thus, we studied intestinal parasitic infections among inmates of the Central Jail, Kathmandu, Nepal.

METHODS

Morning stool samples from 400 inmates (M=282 and F=118), were collected in a clean, dry and wide-mouthed plastic container. The samples were transported to the research laboratory of Shi-Gan International College of Science and Technology, and were fixed using 10% formal saline. Then, samples were processed by formal ether sedimentation concentration technique and were observed microscopically by direct-smear technique.

RESULTS

Six percent (24/400) samples were positive for intestinal parasites, with a gender ratio (M:F) 1.7:1. But, co-parasitism was not observed. Intestinal parasitic infections were higher among 21-40 years age-group, 3.5% (14/262). Similarly, intestinal parasitic infections were higher among 'Dalits' ethnic group, 21.1% (4/19). As compared to helminths, more protozoans, 62.5% (15/24), were observed. Giardia lamblia, 41.67% (10/24), was the most common protozoans while Trichuris trichiura, 25.0% (6/24), was the most common helminths.

CONCLUSIONS

Intestinal parasitic infections were lower among the inmates of Central jail, but such conditions cannot be presumed in other peripheral settings. Pure and safe drinking water supply and the effective deworming campaign can further reduce this figure at this setting and peripheral jails across the country.

Identification of lncRNA-155 encoded by MIR155HG as a novel regulator of innate immunity against influenza A virus infection

Long noncoding RNAs (lncRNAs) are single-stranded RNA molecules longer than 200 nt that regulate many cellular processes. MicroRNA 155 host gene (MIR155HG) encodes the microRNA (miR)-155 that regulates various signalling pathways of innate and adaptive immune responses against viral infections. MIR155HG also encodes a lncRNA that we call lncRNA-155. Here, we observed that expression of lncRNA-155 was markedly upregulated during influenza A virus (IAV) infection both in vitro (several cell lines) and in vivo (mouse model). Interestingly, robust expression of lncRNA-155 was also induced by infections with several other viruses. Disruption of lncRNA-155 expression in A549 cells diminished the antiviral innate immunity against IAV. Furthermore, knockout of lncRNA-155 in mice significantly increased IAV replication and virulence in the animals. In contrast, overexpression of lncRNA-155 in human cells suppressed IAV replication, suggesting that lncRNA-155 is involved in host antiviral innate immunity induced by IAV infection. Moreover, we found that lncRNA-155 had a profound effect on expression of protein tyrosine phosphatase 1B (PTP1B) during the infection with IAV. Inhibition of PTP1B by lncRNA-155 resulted in higher production of interferon-beta (IFN-β) and several critical interferon-stimulated genes (ISGs). Together, these observations reveal that MIR155HG derived lncRNA-155 can be induced by IAV, which modulates host innate immunity during the virus infection via regulation of PTP1B-mediated interferon response.

Diarrheal disease outbreak in Gaidatar village of Rautahat District, Nepal

OBJECTIVE

Diarrheal diseases, including cholera, remain a major public health concern in developing countries like Nepal. This study investigated a diarrheal outbreak that affected over 1500 people in Gaidatar village of Rautahat district in central Nepal and sought to identify the source and causation of the disease. Stool samples were collected from individuals with acute diarrheal illness (n = 16) and healthy non-diarrheal children (n = 39), along with samples from local drinking water sources (n = 8) and their sewage system (n = 10). None of the individuals were sampled multiple times. Diarrheic stool and sewage samples were analysed for the presence of Vibrio cholerae, while coliforms were tested in drinking water samples following standard microbiological protocols. Enteric parasites were tested in both diarrheic and non-diarrheic stool samples.

RESULTS

Vibrio cholerae O1 Ogawa serotype was isolated in 18.7% of the diarrheic stool and 20.0% of the sewage. Coliforms were found in all drinking water samples, with 87.5% testing positive for fecal coliform. Additionally, 43.6% of the stool samples (n = 55) had at least one of the intestinal parasites tested, primarily Giardia lamblia (21.8%). However, almost all parasites were found in non-diarrheal stool. Taken together, our results provide evidence that the diarrheal outbreak was associated with V. cholerae O1 Ogawa serotype, possibly transmitted through the drinking water sources contaminated with fecal matters from their sewage (drainage) system. These findings warrant regular surveillance of drinking water sources to help prevent future outbreaks.

Leukemia-cell proliferation and disease progression in patients with early stage chronic lymphocytic leukemia

The clinical course of patients with recently diagnosed early stage chronic lymphocytic leukemia (CLL) is highly variable. We examined the relationship between CLL-cell birth rate and treatment-free survival (TFS) in 97 patients with recently diagnosed, Rai stage 0–II CLL in a blinded, prospective study, using in vivo²H₂O labeling. Birth rates ranged from 0.07–1.31% new cells per day. With median follow-up of 4.0 years, 33 subjects (34%) required treatment by NCI criteria. High birth rate was observed in 44% of subjects and was significantly associated with shorter TFS, unmutated IGHV status, and expression of ZAP70 and of CD38. In multivariable modeling considering age, gender, Rai stage, expression of ZAP70 or CD38, IGHV mutation status and FISH cytogenetics, only CLL-cell birth rate and IGHV mutation status met criteria for inclusion. Hazard ratios were 3.51 (p=0.002) for high birth rate and 4.93 (p<0.001) for unmutated IGHV. The association between elevated birth rate and shorter TFS was observed in subjects with either mutated or unmutated IGHVs, and the use of both markers was a better predictor of TFS than either parameter alone. Thus, an increased CLL birth rate in early stage disease is a strong predictor of disease progression and earlier treatment.

Study of medically important Vibrios in the sewage of Katmandu Valley, Nepal

A total of 42 samples were collected from the different sites of sewer system of Kathmandu Valley during rainy summer season (June to September 2008) using Moore's technique. Samples (on Moore's swabs) were submersed in alkaline peptone water (pH 8.6) and transported to Research Laboratory of National Institute of Tropical Medicine and Public Health Research, Kathmandu in cold condition (ice chest) followed by incubation at 37 degrees C for 8 hours. After incubation, culture was done on thiosulfate-citrate-bile salt-sucrose (TCBS) agar and incubated at 37 degrees C for overnight (15 hrs). Both yellow and green colonies measuring from 2 to 9 mm in diameter on TCBS agar were subjected for gram staining, biochemical testing as well as sero-typing using antisera (poly O1, Ogawa and Inaba) (Denka Seiken Co. Ltd, Japan). Altogether 46 medically important Vibrios were isolated from 42 samples studied. The isolates were identified as V. cholerae (n = 20; 43.5%), V. vulnificus (n = 11; 23.9%), V. parahaemolyticus (n = 5; 10.9%), V. furnissi (n = 5; 10.9%), V. fluvialis (n = 3; 6.5%) and V. alginolyticus (n = 2; 4.3%). Of the 20 V. cholerae isolates, 13 (65.0%) and 7 (35.0%) isolates were V. cholerae O1 and non-O1, respectively. Among the V. cholerae O1 (n = 13), classical Hikojima strain was most frequently isolated (n = 10) followed by V. cholerae O1 Ogawa (El Tor = 2 and classical = 1). High frequency of V. cholerae isolation from sewer system of Kathmandu Valley is an indication of possible outbreak of cholera anytime in future and, therefore, demands improvement in sanitary condition, supply/consumption of safe drinking water and personal hygiene.

Study of parasitic infection among children of Sukumbasi Basti in Kathmandu valley

Keeping in view of heavy burden of intestinal parasitosis, present study was done to find out the prevalence of intestinal parasitic infection in children (aged <16 years) of Sukumbasi (people living without land ownership) Basti (community) in Kathmandu Valley. A total of 279 stool samples collected in clean, dry and screw capped plastic container were firstly examined for the presence of adult worm and/or segments of worms. Samples fixed in 10% formal-saline were then examined microscopically after concentration by formal-ether sedimentation technique. Overall parasite positive rate was 43.3% (121/279) with no significant difference in two genders (Boys: 48.3%, 73/151; Girls: 37.5%, 48/128) (p=0.07). Altogether 11 species of parasites were detected. Of them Giardia lamblia was most common followed by Entamoeba histolytica, Trichuris trichiura and others. Positive rate was higher in Tibeto-Burman (55.0%, 77/140) and the least in Indo-Aryan (25.4%, 27/ 106) (p=0.01) ethnic groups. Children taking anti-parasitic drug in last six months had significantly low positive rate (25.4%, 15/59) than others (48.2%, 106/220) (p=0.002). Results of this study suggestive of periodic administration of anti-parastic drugs and need for improvement of sanitary/hygienic practice.

Rituximab-based chemotherapy for steroid-refractory autoimmune hemolytic anemia of chronic lymphocytic leukemia

Autoimmune hemolytic anemia (AIHA) is a well known complication of chronic lymphocytic leukemia (CLL). Steroids are the first line of treatment and there are limited effective treatment options for steroid refractory AIHA of CLL. Rituximab, an active agent against B cell malignancies, has also been noted to be active in certain autoimmune hematologic disorders. We used a combination of rituximab, cyclophosphamide and dexamethasone (RCD) in eight CLL patients with steroid refractory AIHA. Rituximab was given at a dose of 375 mg/m(2) i.v. on day 1 (D-1). Cyclophosphamide was given at a dose of 750 mg/m(2) on D-2. Twelve mg of dexamethasone was given i.v. on D-1, D-2 and orally from D-3 to D-7. Cycles were repeated every 4 weeks till the best response. Response in AIHA was evaluated by frequent blood counts and Coombs test. All eight patients achieved a remission of their AIHA. Median pretreatment hemoglobin was 8.3 g/dl and post-treatment hemoglobin was 14.3 g/dl. Five patients converted to Coombs negative after RCD. Median duration of response was 13 months (7-23+). Retreatment with RCD was also effective in achieving a response on relapse of AIHA. Our results indicate that a rituximab-based combination regimen (RCD) is highly effective in treating steroid refractory AIHA of CLL.

Alemtuzumab in previously treated chronic lymphocytic leukemia patients who also had received fludarabine

PURPOSE

This phase II pilot study determined the efficacy and safety of alemtuzumab (Campath-1H; Burroughs Wellcome, United Kingdom) in patients with chronic lymphocytic leukemia (CLL), all of whom had previously received fludarabine and other chemotherapy regimens.

PATIENTS AND METHODS

Twenty-four patients were treated with intravenous alemtuzumab at six centers in the United States. The target dose of 30 mg over 2 hours, three times weekly, was administered for up to 16 weeks. Responses were evaluated by an independent panel of experts using 1996 National Cancer Institute-sponsored Working Group criteria. Safety assessments included analysis of lymphocyte subpopulations. Antimicrobial prophylaxis was not mandatory.

RESULTS

Eight patients (33%) achieved a major response (all partial remissions), with a median time to response of 3.9 months (range, 1.6 to 5.3 months). The median duration of response was 15.4 months (range, 4.6 to >or= 38.0 months), the median time to disease progression was 19.6 months (range, 7.7 to >or= 42.0 months), and the median survival time was 35.8 months (range, 8.8 to >or= 47.1 months). Acute infusion-related events, mainly grades 1 and 2, were most common and most severe in the first week. Ten patients (eight nonresponders and two responders) experienced major infections on-study. Pneumocystis carinii pneumonia was reported in two patients on-study; neither had received prophylaxis. Median CD4+ and CD8+ counts decreased and then began to increase by the end of the study, with further recovery by 1-month follow-up. One of 53 samples obtained from 10 patients had a low titer of alemtuzumab antibodies.

CONCLUSION

Alemtuzumab has significant activity in poor-prognosis, fludarabine-treated CLL patients. However, because of a relatively high incidence of opportunistic infections accompanying profound lymphopenia, future protocols should include mandatory prophylaxis.

Chronic lymphocytic leukemia: case-based session

Drs. Hartmut Döhner, Michael J. Keating, Kanti R. Rai and Emili Montserrat form the panel to review chronic lymphocytic leukemia (CLL) while focusing on the clinical features of a particular patient. The pace of progress in CLL has accelerated in the past decade. The pathophysiological nature of this disease, as had been known in the past, was based largely on the intuitive and empiric notions of two leaders in hematology, William Dameshek and David Galton. Now the works of a new generation of leaders are providing us with the scientific explanations of why CLL is a heterogeneous disease, perhaps consisting of at least two separate entities. In one form of CLL, the leukemic lymphocytes have a surface immunoglobulin (Ig) variable region gene that has undergone somatic mutations, with tell-tale markers suggesting that these cells had previously traversed the germinal centers. Such patients have a distinctly superior prognosis than their counterparts whose leukemic lymphocytes IgV genes have no mutations (these are indeed immunologically naive cells), who have a worse prognosis. The introduction of fluorescence in situ hybridization (FISH) technique has provided us with new insights into the diverse chromosomal abnormalities that can occur in CLL, and which have significant impact on the clinical behavior and prognosis of patients with this disease. Major advances in therapeutics of CLL also have occurred during the past decade. Two monoclonal antibodies, Campath-1H (anti-CD52) and rituximab (anti-CD20), and one nucleoside analogue, fludarabine, have emerged as three agents of most promise in the front-line treatment of this disease. Studies currently in progress reflect our attempts to find the most effective manner of combining these agents to improve the overall survival statistics for CLL patients. As in many other hematological malignancies, high dose chemotherapy followed by autologous or HLA-compatible allogeneic stem cells rescue strategies are under study as a salvage treatment for a relatively younger age group of CLL patients with poor prognosis characteristics.

Impact of therapy With chlorambucil, fludarabine, or fludarabine plus chlorambucil on infections in patients with chronic lymphocytic leukemia: Intergroup Study Cancer and Leukemia Group B 9011

PURPOSE

We sought to determine whether therapy with single-agent fludarabine compared with chlorambucil alone or the combination of both agents had an impact on the incidence and spectrum of infections among a series of previously untreated patients with B-cell chronic lymphocytic leukemia (CLL).

PATIENTS AND METHODS

Five hundred fifty-four previously untreated CLL patients with intermediate/high-risk Rai-stage disease were enrolled onto an intergroup protocol. Patients were randomized to therapy with chlorambucil, fludarabine, or fludarabine plus chlorambucil. Data pertaining to infection were available on 518 patients. Differences in infections among treatment arms were tested with the Kruskal-Wallis, Wilcoxon, and chi(2) tests.

RESULTS

A total of 1,107 infections (241 major infections) occurred in 518 patients over the infection follow-up period (interval from study entry until either reinstitution of initial therapy, therapy with a second agent, or death). Patients treated with fludarabine plus chlorambucil had more infections than those receiving either single agent (P <.0001). Comparing the two single-agent arms, there were more infections on the fludarabine arm (P =.055) per month of follow-up. Fludarabine therapy was associated with more major infections and more herpesvirus infections compared with chlorambucil (P =.008 and P =.004, respectively). Rai stage and best response to therapy were not associated with infection. A low serum immunoglobulin G was associated with number of infections (P =.02). Age was associated with incidence of major infection in the combination arm (P =.004).

CONCLUSION

Combination therapy with fludarabine plus chlorambucil resulted in significantly more infections than treatment with either single agent. Patients receiving single-agent fludarabine had more major infections and herpesvirus infections compared with chlorambucil-treated patients.

Fludarabine compared with chlorambucil as primary therapy for chronic lymphocytic leukemia

BACKGROUND

Fludarabine is an effective treatment for chronic lymphocytic leukemia that does not respond to initial treatment with chlorambucil. We compared the efficacy of fludarabine with that of chlorambucil in the primary treatment of chronic lymphocytic leukemia.

METHODS

Between 1990 and 1994, we randomly assigned 509 previously untreated patients with chronic lymphocytic leukemia to one of the following treatments: fludarabine (25 mg per square meter of body-surface area, administered intravenously daily for 5 days every 28 days), chlorambucil (40 mg per square meter, given orally every 28 days), or fludarabine (20 mg per square meter per day for 5 days every 28 days) plus chlorambucil (20 mg per square meter every 28 days). Patients with an additional response at each monthly evaluation continued to receive the assigned treatment for a maximum of 12 cycles.

RESULTS

Assignment of patients to the fludarabine-plus-chlorambucil group was stopped when a planned interim analysis revealed excessive toxicity and a response rate that was not better than the rate with fludarabine alone. Among the other two groups, the response rate was significantly higher for fludarabine alone than for chlorambucil alone. Among 170 patients treated with fludarabine, 20 percent had a complete remission, and 43 percent had a partial remission. The corresponding values for 181 patients treated with chlorambucil were 4 percent and 33 percent (P< 0.001 for both comparisons). The median duration of remission and the median progression-free survival in the fludarabine group were 25 months and 20 months, respectively, whereas both values were 14 months in the chlorambucil group (P<0.001 for both comparisons). The median overall survival among patients treated with fludarabine was 66 months, which was not significantly different from the overall survival in the other two groups (56 months with chlorambucil and 55 months with combined treatment). Severe infections and neutropenia were more frequent with fludarabine than with chlorambucil (P=0.08), although, overall, toxic effects were tolerable with the two single-drug regimens.

CONCLUSIONS

When used as the initial treatment for chronic lymphocytic leukemia, fludarabine yields higher response rates and a longer duration of remission and progression-free survival than chlorambucil.

Future strategies toward the cure of indolent B-cell malignancies. New biologic therapies

Although chronic lymphocytic leukemia (CLL) cells provide an excellent target for antibody therapy, to date this approach has met with limited success in patients with CLL. Promising data are emerging with a new generation of antibodies, such as Campath-1H, which may offer effective therapeutic options not only as single agents but also in combination with such drugs as fludarabine. Other new antibodies, including rituximab and several new radioimmunoconjugates, have provided impressive results in the indolent non-Hodgkin's lymphomas and warrant further investigation.

Ig V gene mutation status and CD38 expression as novel prognostic indicators in chronic lymphocytic leukemia

Cellular immunophenotypic studies were performed on a cohort of randomly selected IgM(+) B-chronic lymphocytic leukemia (B-CLL) cases for which Ig V(H) and V(L) gene sequences were available. The cases were categorized based on V gene mutation status and CD38 expression and analyzed for treatment history and survival. The B-CLL cases could be divided into 2 groups. Those patients with unmutated V genes displayed higher percentages of CD38(+) B-CLL cells (>/=30%) than those with mutated V genes that had lower percentages of CD38(+) cells (<30%). Patients in both the unmutated and the >/=30% CD38(+) groups responded poorly to continuous multiregimen chemotherapy (including fludarabine) and had shorter survival. In contrast, the mutated and the <30% CD38(+) groups required minimal or no chemotherapy and had prolonged survival. These observations were true also for those patients who stratified to the Rai intermediate risk category. In the mutated and the <30% CD38(+) groups, males and females were virtually equally distributed, whereas in the unmutated and the >/=30% CD38(+) groups, a marked male predominance was found. Thus, Ig V gene mutation status and the percentages of CD38(+) B-CLL cells appear to be accurate predictors of clinical outcome in B-CLL patients. These parameters, especially CD38 expression that can be analyzed conveniently in most clinical laboratories, should be valuable adjuncts to the present staging systems for predicting the clinical course in individual B-CLL cases. Future evaluations of new therapeutic strategies and drugs should take into account the different natural histories of patients categorized in these manners.

Delphi-panel analysis of appropriateness of high-dose therapy and bone marrow transplants in chronic myelogenous leukemia in chronic phase

BACKGROUND

It is uncertain which people with chronic myelogenous leukemia (CML) in chronic phase should receive conventional treatment (interferon and/or chemotherapy) versus high-dose therapy and a bone marrow transplant. There are no randomized trials comparing these approaches and analyses of data from non-randomized studies are complex, contradictory without sufficient detail to allow subject-level treatment decisions.

OBJECTIVE

Determine appropriateness of high-dose therapy and bone marrow transplants in persons with CML in chronic phase with specific features. Develop a treatment algorithm. PANELISTS: nine leukemia experts from diverse geographic sites and practice settings.

EVIDENCE

Boolean MEDLINE searches of chronic myelogenous leukemia and chemotherapy and/or transplants.

CONSENSUS PROCESS

We used a modified Delphi-panel group judgment process. Age, prognostic score, disease duration, and type of conventional therapy and response were permuted to define 90 clinical settings. Each panelist rated appropriateness of high-dose therapy and a transplant versus conventional therapy on a 9-point ordinal scale (1, most inappropriate, 9, most appropriate) considering three types of donors: (1) HLA-identical siblings; (2) alternative donors (HLA-matched related or unrelated people other than an HLA-identical sibling); and (3) autotransplants. An appropriateness index was developed based on median rating and amount of disagreement. Relationship of appropriateness indices to permuted clinical variables was considered by analysis of variance and recursive partitioning. Preference between donor types was analyzed by comparing mean appropriateness indices of similar settings and a treatment algorithm developed.

CONCLUSIONS

In people with CML in chronic phase and an HLA-identical sibling donor and in those with an alternative donor (but no HLA-identical sibling), a transplant was rated appropriate in those with a < or = partial cytogenetic response to interferon and uncertain or inappropriate in all other settings. Autotransplants were rated uncertain or inappropriate in all settings. Most of the variance in appropriateness ratings between different clinical settings was accounted for by response to interferon: complete versus < or = partial response. An HLA-identical sibling donor, when available, was always preferred to an alternative donor or autotransplant. In people without an HLA-identical sibling, an alternative donor was favored over an autotransplant at higher appropriateness indices and the converse at lower appropriateness indices.

Delphi-panel analysis of appropriateness of high-dose therapy and bone marrow transplants in adults with acute myelogenous leukemia in 1st remission

BACKGROUND

Despite considerable data, there is still controversy over which adults with acute myelogenous leukemia (AML) in 1st remission should receive high-dose therapy and a bone marrow transplant rather than conventional-dose chemotherapy. Analyses of data from randomized trials are complex, conclusions sometimes contradictory and results not sufficiently detailed to allow subject-level decisions.

OBJECTIVE

To determine appropriate use of high-dose therapy and bone marrow transplants in persons with AML in 1st remission with specific features. Develop a treatment algorithm. PANELISTS: Nine leukemia experts from diverse geographic sites and practice settings.

EVIDENCE

Boolean MEDLINE searches of acute myelogenous leukemia and chemotherapy and/or transplants.

CONSENSUS PROCESS

We used a modified Delphi-panel group judgment process. Age, WBC, cytogenetics and FAB-type were permuted to define 72 clinical settings. Each panelist rated appropriateness of high-dose therapy and a transplant versus conventional-dose chemotherapy on a nine-point ordinal scale (1, most inappropriate, 9, most appropriate) considering 3 types of donors: (1) HLA-identical siblings; (2) alternative donors (HLA-matched related or unrelated people other than an HLA-identical sibling); and (3) autotransplants. An appropriateness index was developed based on median rating and amount of disagreement. The relationship of appropriateness indices to the permuted clinical variables was considered by analysis of variance and recursive partitioning. Preference between donor types was analyzed by comparing mean appropriateness indices of comparable settings and a treatment algorithm developed.

CONCLUSIONS

In people with an HLA-identical sibling, this type of transplant was rated appropriate in those with unfavorable cytogenetics and uncertain in all other settings. In people without an HLA-identical sibling, an alternative donor transplant was rated appropriate in those < 30 years with unfavorable cytogenetics, uncertain in those > 30 years and unfavorable cytogenetics and inappropriate in all other settings. Autotransplants were rated appropriate in people with unfavorable cytogenetics and uncertain in all other settings. An HLA-identical sibling donor, when available, was always preferred to an alternative donor transplant or autotransplant. In people without an HLA-identical sibling, an autotransplant was almost always favored over an alternative donor transplant with the magnitude of preference inversely correlated with transplant appropriateness.

Delphi-panel analysis of appropriateness of high-dose therapy and bone marrow transplants in adults with acute lymphoblastic leukemia in first remission

BACKGROUND

There is controversy over whether high-dose therapy and a bone marrow transplant is better than conventional-dose chemotherapy in adults with acute lymphoblastic leukemia (ALL) in first remission. This decision may depend on which type of donor is available: an HLA-identical sibling, an alternative donor transplant (HLA-matched related or unrelated people other than HLA-identical siblings), or autotransplant.

OBJECTIVE

To determine the appropriate use of high-dose therapy and bone marrow transplants in ALL in first remission. Develop a treatment algorithm. PANELISTS: Nine leukemia experts from diverse geographic sites and practice settings.

EVIDENCE

Boolean MEDLINE searches of acute lymphoblastic leukemia and chemotherapy and/or transplants.

CONSENSUS PROCESS

We used a modified Delphi-panel group judgment process. Age, white blood cell (WBC) count, cytogenetics and immune type were permuted to define 48 clinical settings. Each panelist rated appropriateness of high-dose therapy and a transplant versus conventional-dose chemotherapy on a 9-point ordinal scale (1, most inappropriate; 9, most appropriate) considering three types of donors: (1) HLA-identical siblings; (2) alternative donors; and (3) autotransplants. An appropriateness index was developed based on median rating and amount of disagreement. Relationship of appropriateness indices to the permuted clinical variables was considered by analysis of variance and recursive partitioning. Preference between donor types was analyzed by comparing mean appropriateness indices of comparable settings and a treatment algorithm was developed.

CONCLUSIONS

In people with an HLA-identical sibling donor, transplants were rated appropriate in those with unfavorable cytogenetics and uncertain in all other settings. An HLA-identical sibling donor was always preferred to an alternative donor or autotransplant. In people without an HLA-identical sibling but with an alternative donor, this type of transplant was rated appropriate in those with unfavorable cytogenetics. However, an autotransplant was preferred over an alternative donor transplant in all other settings where a transplant was rated uncertain. In people without an HLA-identical sibling or alternative donor, autotransplants were rated uncertain in all settings except in those with not unfavorable cytogenetics, WBC < 100 x 10(9) l(-1) and T- or pre-B-cell type where they were rated inappropriate.

Cladribine for the treatment of hairy cell leukemia and chronic lymphocytic leukemia

Cladribine (Leustatin; Janssen-Cilag, Ortho Biotech Inc, Raritan, NJ) is a novel injectable nucleoside analogue with marked efficacy against hairy cell leukemia and considerable, although less dramatic, activity against chronic lymphocytic leukemia and non-Hodgkin's lymphoma. The effect is thought to be due to the drug's ability, after intracellular phosphorylation, to inhibit repair of single-strand DNA breaks in certain malignant lymphocyte and monocyte subtypes. We treated 49 patients with active hairy cell leukemia with continuous infusion of cladribine at a dose of 0.1 mg/kg/ d for 7 days. A single course of therapy gave a complete response rate of 76% and a partial response rate of 24%; the effect was durable for several years in most cases. We also treated 14 patients with chronic lymphocytic leukemia with cladribine and obtained an overall response rate of 43%; this required several courses of monthly treatment. These responses tended to be short-lived and did not substantially change life expectancy of chronic lymphocytic leukemia patients. In both diseases, myelosuppression and immunosuppression, sometimes resulting in neutropenic fever, were the only toxicities associated with cladribine.

Old and new therapies in chronic lymphocytic leukemia: now is the time for a reassessment of therapeutic goals

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia for which therapeutic options remain unsatisfying as cure has remained elusive. Recent laboratory discoveries and promising results from completed phase III studies with fludarabine provide reason to reassess therapeutic goals in the treatment of patients with symptomatic CLL. Early enrollment of patients on protocols using combination therapies with fludarabine and new agents such as flavopiridol, IDEC-C2B8, Campath-1H, UCN-01, bryostatin, FR 901228, and melarsoprol will hopefully represent the next advance to improved overall survival and ultimately the cure of CLL.

Chronic lymphocytic leukemia in the elderly population

Chronic lymphocytic leukemia (CLL) is a disease of the elderly with an incidence of about 20 to 30 per 100,000 population in the group aged 70 years or older. Chemotherapy with chlorambucil controls major clinical features of CLL but without prolongation of survival time. Addition of prednisone is necessary when autoimmune complications occur, but its usage in the elderly requires special caution. Fludarabine has better response rates than chlorambucil in treating CLL and has been proved to be an effective salvage therapy in patients previously treated with chlorambucil.

Treatment of hairy-cell leukemia with cladribine: response, toxicity, and long-term follow-up

PURPOSE

To analyze initial and long-term outcomes after treatment of patients with active hairy-cell leukemia (HCL) with a single cycle of cladribine (2-CdA).

PATIENTS AND METHODS

Forty-nine patients with active HCL were treated with 2-CdA by continuous intravenous infusion at 0.1 mg/kg/d for a total of 7 days at the Long Island Jewish Medical Center between September 1990 and August 1992. Here we report on all patients followed-up until April 1996.

RESULTS

At 3 months after treatment, complete response (CR) occurred in 37 patients (76%) and partial response (PR) occurred in 12 patients (24%), for an overall response rate of 100% (95% confidence interval, 94% to 100%). At a median follow-up of 55 months, the relapse-free survival is 80% and overall survival is 95%. Ten patients (20%) have relapsed. Of the 26 patients in whom lymphocyte phenotyping was performed, four were found to have a CD25-negative phenotype. All four of these patients had PRs only and all relapsed. Eight patients have been re-treated with 2-CdA, and all achieved at least a partial remission; two of these have already relapsed with remission durations of less than 1 year. Five second malignancies have occurred in four patients.

CONCLUSION

With a median follow-up of more than 4 years, 39 patients (80%) continue in remission. Only two deaths have occurred. A CD25-negative phenotype may predict for a poorer response to 2-CdA. Patients who relapse may be re-treated with 2-CdA, but subsequent remissions may be of shorter duration. There has not been a markedly increased incidence of second malignancies or late opportunistic infections.

Supportive telephone intervention for patients receiving chemotherapy. A pilot study

Psychosocial interventions have been shown to improve quality of life (QOL) for many cancer patients. A pilot study was conducted to assess the feasibility of a psychoeducational intervention for cancer patients receiving chemotherapy. Eight patients receiving chemotherapy for colorectal carcinoma participated. The intervention is based on a modification of Interpersonal Therapy. It consisted of four sessions, administered biweekly, using a manual format, by a psychiatric nurse clinician over the telephone. The participants also completed a set of QOL measures by telephone to assess tolerance of the planned assessment. The patients received assistance with treatment-related side effects, reported improved ability to communicate with their physician, and gained an understanding of the stresses they discussed. The patients felt satisfied with the emotional support and medical information provided. A randomized trial is planned to test the intervention for patients participating in a cooperative trial sponsored by the National Cancer Institute.

The induction of p53 and WAF1/CIP1 in chronic lymphocytic leukemia cells treated with 2-chlorodeoxyadenosine

The treatment of chronic lymphocytic leukemia includes the use of alkylating agents, steroids, and more recently nucleoside analogues. While prior studies have described potential mechanisms of 2-chlorodeoxyadenosine cytotoxicity including the accumulation of DNA strand breaks and induction of apoptosis or programmed cell death, the expression of p53 and its downstream target WAF1/CIP1 have not been examined. In this report we describe the induction of p53 and WAF1/CIP1 in the apoptotic chronic lymphocytic leukemia cells after exposure to 2-chlorodeoxyadenosine.

Recombinant alpha-2b-interferon in therapy of previously untreated hairy cell leukemia: long-term follow-up results of study by Cancer and Leukemia Group B

In 1985, Cancer and Leukemia Group B initiated a multi-institutional study to define the role of interferon alpha in therapy of previously untreated active hairy cell leukemia (HCL). This is a long-term follow-up report of the study. Fifty-five evaluable patients were treated with recombinant interferon-2b 2 million units/m2 subcutaneously three times a week for 1 year. Treatment was well tolerated; toxicity mainly consisted of flu-like syndrome and pancytopenia, both of a transient nature. Seventy-three percent of patients had objective beneficial responses with 8.3 months median time to achieve at least a partial response (PR). After 1 year of therapy, the patients have been observed for a median of 5 years. There was a continual trend towards relapse throughout this period but 28% have remained in remission beyond 6 years. Forty-six patients (83%) are alive at 6 years. Among the 40 patients who achieved at least a PR, there were 28 with splenomegaly at the beginning of study: the spleen size was reduced in all with interferon alpha therapy and none required splenectomy. This study confirms the results of other investigators, and demonstrates that recombinant alpha interferon-2b is an effective agent for treatment of hairy cell leukemia.

Impaired interferon alpha response in hairy cell leukemia is corrected by therapy with 2-chloro-2'-deoxyadenosine: implications for susceptibility to opportunistic infections

Patients with hairy cell leukemia (HCL) are susceptible to opportunistic intracellular infections, suggesting defects in cellular immunity. Prior studies have indicated an association between failure of IFN-alpha generation by peripheral blood mononuclear cells (MNC) and susceptibility to such infections. We here present results on IFN-alpha generation in HCL patients pre- and post-therapy. Prior to treatment with 2-chloro-2'-deoxyadenosine (CdA), MNC from 24 HCL patients with active disease produced little or not IFN-alpha (geometric mean < 40 IU/ml) compared with controls (n = 140, geometric mean 1730 IU/ml, p < 0.0005). After treatment with CdA, IFN-alpha generation was studied in 16 patients, with a geometric mean value of 650 IU/ml (p < 0.0005 compared with pre-CdA levels). The severe depression of IFN-alpha generation improved progressively following CdA therapy-induced clinical remission. We propose that deficiency of IFN-alpha production may play a role in the susceptibility to intracellular infections of patients with active HCL.

Progress in chronic lymphocytic leukaemia: a historical perspective

A historical review of gains in the body of knowledge on chronic lymphocytic leukaemia (CLL) reveals a continuous, steady process from the beginning of the century with the pioneering work of scholars to the present era of molecular biology. Several notable hallmarks of this progress have been recognized: (1) the early period of broad, loose grouping of all chronic lymphoproliferative disorders; (2) recognition of CLL as a discrete entity with clinical and cytological identification of different forms of lymphoid neoplasm; (3) development of clinical staging systems and prognostic factors; and (4) use of immunological techniques in the study of CLL. Studies currently in progress using molecular genetic techniques hold promise for future advances in unravelling the biology of leukaemic transformation of lymphocytes in CLL.

5th International Workshop on Chronic Lymphocytic Leukemia

In the past few years important advances have been made in our understanding of the biology and natural history of CLL; also, new strategies and agents offer promise in the treatment of this form of leukemia. Now, patients can be treated on a more rationale basis and with real prospects for a sustained control of their disease, and improved quality of life. Hopefully, progresses in CLL will continue to accumulate in the coming years.

Distinct characteristics of lymphokine-activated killer (LAK) cells derived from patients with B-cell chronic lymphocytic leukemia (B-CLL). A factor in B-CLL serum promotes natural killer cell-like LAK cell growth

We show that lymphokine-activated killer (LAK) cell precursors derived from patients with B-cell chronic lymphocytic leukemia (B-CLL) and cultured in the presence of recombinant interleukin-2 and normal human serum (NHS), develop into primarily NK cell-like (CD 57+) LAK cells, whereas identically prepared LAK cell precursors from normal subjects develop into mainly T cell-like (CD 3+, CD 8+) LAK cells. B-CLL LAK cells exhibited greater proliferative capacity than did normal LAK cells. When normal LAK cells were grown in B-CLL serum instead of NHS, their proliferation increased; NK cell levels also increased to those found in B-CLL LAK cells, suggesting that B-CLL serum contains a factor that promotes NK cell-like growth, LAK cells derived from normal or B-CLL patients demonstrated similar lytic activity toward K562 and Raji cells. Growth in B-CLL serum did not reduce their lytic potential. Thus, the altered phenotype and growth exhibited by B-CLL LAK cells and normal LAK cells grown in B-CLL serum does not lead to abnormalities in their cytolytic functions. We propose instead that the predominance of NK-like cells in B-CLL LAK cell populations and the presence of an NK cell-like growth factor in B-CLL serum reflect abnormalities related to NK cell-mediated B-cell regulation; ie, either inhibition of normal B-cell growth and/or growth stimulation of the leukemic clone in B-CLL.

Chronic lymphocytic leukemia: new insights into biology and therapy

PURPOSE

To review the recent advances in the biologic and clinical research of chronic lymphocytic leukemia.

DATA IDENTIFICATION

English-language literature search using MEDLINE (1980 to 1990) and CANCERLIT (1980 to 1990), review of meeting abstracts and reports, and an extensive manual search of bibliographies of identified articles.

STUDY SELECTION

Approximately 800 articles, abstracts, and book chapters were selected for analysis.

DATA EXTRACTION

The literature was reviewed and 227 articles were selected as representative of the important advances in chronic lymphocytic leukemia.

RESULTS OF DATA SYNTHESIS

Chronic lymphocytic leukemia is a disease of lymphocytes that appear to be mature but are biologically immature. These B lymphocytes arise from a subset of CD5-B cells that appear to have a role in autoimmunity. The pathogenesis of chronic lymphocytic leukemia is likely a multistep process, initially involving a polyclonal expansion of CD5-B cells followed by transformation of a single cell. Chromosome studies indicate that trisomy 12 is the most common abnormality, followed by 14q+, 13q, and 11q. These abnormalities portend a poor prognosis. Recent progress in the treatment of chronic lymphocytic leukemia involves three new drugs: fludarabine, pentostatin, and 2-chlorodeoxyadenosine. Recent preliminary results of allogeneic bone marrow transplantation present insights into the potential curability of chronic lymphocytic leukemia. Therapy with intravenous immunoglobulin can prevent or delay moderate bacterial infections in persons with chronic lymphocytic leukemia.

CONCLUSION

Major advances in the biologic research of chronic lymphocytic leukemia have resulted in new understanding of this complex disease. New therapies, such as those with intravenous immunoglobulin and fludarabine, may lead to improved outcome.

Characteristics of CD11c+CD5+ chronic B-cell leukemias and the identification of novel peripheral blood B-cell subsets with chronic lymphoid leukemia immunophenotypes

Previous studies have indicated that chronic lymphocytic leukemias (CLL) are characterized by the coexpression of CD5 and B-cell antigens, while hairy cell leukemias (HCL) typically express CD11c+CD5- B-cell immunophenotypes. In this report we describe the features of B-cell leukemias with CD11c+CD5+ immunophenotypes and the identification of novel circulating B-cell subsets defined by the expression of CD20, CD5, and CD11c antigens. Morphologic evaluation of 14CD11c+CD5+ B-cell leukemias showed that they generally had larger cellular diameters (14 to 21 microns) and lower nuclear:cytoplasm ratios than typical small lymphocyte CLL. These cases did not exhibit the well-defined nucleoli characteristic of prolymphocytic leukemia (PLL). The presenting clinical features of CD11c+CD5+ B-cell leukemias were most consistent with CLL or PLL, and none of the evaluated cases had pancytopenia, splenomegaly, and cytoplasmic villi characteristic of HCL. Examination of normal peripheral blood (n = 6) by three-color flow cytometry identified four novel B-cell subsets with the following immunophenotypes (mean percent of total CD20+ B cells +/- SE): CD20+CD5+CD11c+ (8.0 +/- 1.6); CD20+CD5-CD11c+ (12.0 +/- 2.0); CD20+CD5+CD11c- (35.0 +/- 4.9); and CD20+CD5-CD11c- (44.0 +/- 5.0). Our findings suggest that CD11c+CD5+ B-cell leukemias with atypical morphologic features represent forms of CLL or PLL rather than HCL. In addition, we have identified novel subsets of circulating B cells defined by patterns of CD20, CD5, and CD11c expression that correspond to the immunophenotypes of chronic B-cell leukemias.

Prognostic factors and clinical staging in chronic lymphocytic leukemia

There has been significant progress in the past 10 years in our ability to prospectively predict prognosis in CLL. The clinical staging systems have helped us identify three broad groups of patients with respect to their overall outlook for survival: low risk (stage 0), intermediate risk (stages I and II), and high risk (stages III and IV). It seems reasonable to distinguish those low- and intermediate-risk patients who are likely to have a benign or indolent clinical course if their blood lymphocyte doubling time is longer than 12 months and their bone marrow biopsy pattern of lymphocytic infiltration is nondiffuse. With these guidelines, it will be possible to initiate meaningful and reliable therapeutic trials in CLL in the immediate future.

Management of chronic lymphocytic leukemia

Significant progress has been made in the past two decades in the understanding of immunobiology of CLL and the development of clinical staging systems and identification of other prognostic factors in CLL. A significant advance in the management of CLL has also been made. Now we know when to initiate therapy. We recommend that patients with stage 0 and patients with stages I and II associated with good prognostic features such as absence of disease-related symptoms, long lymphocyte doubling time, nondiffuse bone marrow infiltration, and low tumor load not be treated; they should be followed at 2- to 6-month intervals. We recommend initiation of therapy for patients with stages I and II, associated with poor prognostic features such as presence of disease-related symptoms, short lymphocyte doubling time, diffuse bone marrow infiltration, and high tumor load and for patients with stages III and IV. However, we still do not know what constitutes the optimal therapy for the disease. In one large randomized study, the response rate as well as survival superiority of CHOP (with low-dose Adriamycin) over COP in previously untreated patients with stage C disease was observed. In another large randomized study, only a response rate advantage of CHOP (with standard dose Adriamycin) over chlorambucil and prednisone (in previously untreated patients with stages B and C) was seen. No randomized studies have compared CHOP versus chlorambucil and prednisone in patients with stages III and IV or stage C. At present, our recommendation for the treatment of patients with advanced disease is chlorambucil and prednisone therapy. New drugs under clinical trials for CLL include (1) deoxycoformycin, (2) 2-chlorodeoxyadenosine, and (3) fludarabine monophosphate. Both deoxycoformycin and 2-chlorodeoxyadenosine have been shown to have some activity in previously treated CLL patients with advanced disease. The effectiveness of these agents, however, has not been tested yet in untreated patients with advanced disease. Fludarabine monophosphate, on the other hand, has been shown to be very effective in both previously treated and untreated patients with advanced disease. Allogeneic bone marrow transplantation recently has been found to be of benefit in some patients (37 to 46 years) in a preliminary study; this therapeutic procedure should be tested further in a larger population of younger patients (less than 50 years) with advanced CLL. New agents such as lymphokines (interferons and IL-2) and monoclonal antibodies have been investigated for their efficacy and found to be minimally effective in previously treated patients with advanced disease.(ABSTRACT TRUNCATED AT 400 WORDS)