Reinforced versus standard stapler transection on postoperative pancreatic fistula in distal pancreatectomy: multicentre randomized clinical trial.

BACKGROUND: Postoperative pancreatic fistula is the leading cause of morbidity after distal pancreatectomy. Strategies investigated to reduce the incidence have been disappointing. Recent data showed a reduction in postoperative pancreatic fistula with the use of synthetic mesh reinforcement of the staple line. METHODS: An RCT was conducted between May 2014 and February 2016 at four tertiary referral centres in Sweden. Patients scheduled for distal pancreatectomy were eligible. Enrolled patients were randomized during surgery to stapler transection with biological reinforcement or standard stapler transection. Patients were blinded to the allocation. The primary endpoint was the development of any postoperative pancreatic fistula. Secondary endpoints included morbidity, mortality, and duration of hospital stay. RESULTS: Some 107 patients were randomized and 106 included in an intention-to-treat analysis (56 in reinforced stapling group, 50 in standard stapling group). No difference was demonstrated in terms of clinically relevant fistulas (grade B and C): 6 of 56 (11 per cent) with reinforced stapling versus 8 of 50 (16 per cent) with standard stapling (P = 0.332). There was no difference between groups in overall postoperative complications: 45 (80 per cent) and 39 (78 per cent) in reinforced and standard stapling groups respectively (P = 0.765). Duration of hospital stay was comparable: median 8 (range 2-35) and 9 (2-114) days respectively (P = 0.541). CONCLUSION: Biodegradable stapler reinforcement at the transection line of the pancreas did not reduce postoperative pancreatic fistula compared with regular stapler transection in distal pancreatectomy. Registration number: NCT02149446 (http://www.clinicaltrials.gov).

Reassuringly low carriage of enteropathogens among healthy Swedish children in day care centres.

OBJECTIVES: Infectious gastroenteritis is one of the most common diseases among children and has a considerable impact on health and socio-economy. Day care centres are high-risk environments for infections. The aim of this study was to investigate if asymptomatic preschool children constitute a reservoir for potential enteropathogens. STUDY DESIGN: In total, 438 individual diapers were collected from day care centres in Uppsala, Sweden, during spring and autumn, and molecular techniques were used to estimate the prevalence of asymptomatic carriage of multiple enteropathogens. METHODS: Faecal samples were analysed with multiplex polymerase chain reaction (PCR) (xTAG® Gastrointestinal Pathogen Panel; Luminex Corporation, Toronto, Canada) targeting 21 different pathogens. Samples with a median fluorescence intensity above threshold were re-analysed with a second PCR assay. RESULTS: Sixteen of the 438 samples were positive for enteropathogens, 1.6% for enteric adenovirus, 0.7% for Campylobacter spp., and 0.7% for norovirus. CONCLUSIONS: Preschool children in Uppsala constitute a limited reservoir for potential enteropathogens.

Impact of delay between imaging and treatment in patients with potentially curable pancreatic cancer.

BACKGROUND: Locoregional pancreatic ductal adenocarcinoma (PDAC) may progress rapidly and/or disseminate despite having an early stage at diagnostic imaging. A prolonged interval from imaging to resection might represent a risk factor for encountering tumour progression at laparotomy. The aim of this study was to determine the therapeutic window for timely surgical intervention. METHODS: This observational cohort study included patients with histologically confirmed PDAC scheduled for resection with curative intent from 2008 to 2014. The impact of imaging-to-resection/reassessment (IR) interval, vascular involvement and tumour size on local tumour progression or presence of metastases at reimaging or laparotomy was evaluated using univariable and multivariable regression. Risk estimates were approximated using hazard ratios (HRs). RESULTS: Median IR interval was 42 days. Of 349 patients scheduled for resection, 82 had unresectable disease (resectability rate 76.5 per cent). The unresectability rate was zero when the IR interval was 22 days or shorter, and was lower for an IR interval of 32 days or less compared with longer waiting times (13 versus 26.2 per cent; HR 0.42, P = 0.021). It was also lower for tumours smaller than 30 mm than for larger tumours (13.9 versus 32.5 per cent; HR 0.34, P < 0.001). Tumours with no or minor vascular involvement showed decreased rates of unresectable disease (20.6 per cent versus 38 per cent when there was major or combined vascular involvement; HR 0.43, P = 0.007). However, this failed to reach statistical significance on multivariable analysis (P = 0.411), in contrast to IR interval (P = 0.028) and tumour size (P < 0.001). CONCLUSION: Operation within 32 days of diagnostic imaging reduced the risk of tumour progression to unresectable disease by half compared with a longer waiting time. The results of this study highlight the importance of efficient clinical PDAC management.

Serological evaluation of possible exposure to Ljungan virus and related parechovirus in autoimmune (type 1) diabetes in children.

Exposure to Ljungan virus (LV) is implicated in the risk of autoimmune (type 1) diabetes but possible contribution by other parechoviruses is not ruled out. The aim was to compare children diagnosed with type 1 diabetes in 2005-2011 (n = 69) with healthy controls (n = 294), all from the Jämtland County in Sweden, using an exploratory suspension multiplex immunoassay for IgM and IgG against 26 peptides of LV, human parechoviruses (HPeV), Aichi virus and poliovirus in relation to a radiobinding assay (RBA) for antibodies against LV and InfluenzaA/H1N1pdm09. Islet autoantibodies and HLA-DQ genotypes were also determined. 1) All five LV-peptide antibodies correlated to each other (P < 0.001) in the suspension multiplex IgM- and IgG-antibody assay; 2) The LV-VP1_31-60-IgG correlated with insulin autoantibodies alone (P = 0.007) and in combination with HLA-DQ8 overall (P = 0.022) as well as with HLA-DQ 8/8 and 8/X subjects (P = 0.013); 3) RBA detected LV antibodies correlated with young age at diagnosis (P < 0.001) and with insulin autoantibodies (P < 0.001) especially in young HLA-DQ8 subjects (P = 0.004); 4) LV-peptide-VP1_31-60-IgG correlated to RBA LV antibodies (P = 0.009); 5) HPeV3-peptide-IgM and -IgG showed inter-peptide correlations (P < 0.001) but only HPeV3-VP1_1-30-IgG (P < 0.001) and VP1_95-124-IgG (P = 0.009) were related to RBA LV antibodies without relation to insulin autoantibody positivity (P = 0.072 and P = 0.486, respectively). Both exploratory suspension multiplex IgG to LV-peptide VP1_31-60 and RBA detected LV antibodies correlated with insulin autoantibodies and HLA-DQ8 suggesting possible role in type 1 diabetes. It remains to be determined if cross-reactivity or concomitant exposure to LV and HPeV3 contributes to the seroprevalence.

Hospital teaching status and volume related to mortality after pancreatic cancer surgery in a national cohort.

BACKGROUND: The association between hospital teaching status and mortality after pancreatic resection is not well explored. Although hospital volume is related to short-term mortality, the effect on long-term survival needs investigation, taking into account hospital teaching status and selective referral patterns. METHODS: This was a nationwide retrospective register-based cohort study of patients undergoing pancreatic resection between 1990 and 2010. Follow-up for survival was carried out until 31 December 2011. The associations between hospital teaching status and annual hospital volume and short-, intermediate- and long-term mortality were determined by use of multivariable Cox regression models, which provided hazard ratios (HRs) with 95 per cent c.i. The analyses were mutually adjusted for hospital teaching status and volume, as well as for patients' sex, age, education, co-morbidity, type of resection, tumour site and histology, time interval, referral and hospital clustering. RESULTS: A total of 3298 patients were identified during the study interval. Hospital teaching status was associated with a decrease in overall mortality during the latest interval (years 2005-2010) (university versus non-university hospitals: HR 0·72, 95 per cent c.i. 0·56 to 0·91; P = 0·007). During all time periods, hospital teaching status was associated with decreased mortality more than 2 years after surgery (university versus non-university hospitals: HR 0·86, 0·75 to 0·98; P = 0·026). Lower annual hospital volume increased the risk of short-term mortality (HR for 3 or fewer compared with 4-6 pancreatic cancer resections annually: 1·60, 1·04 to 2·48; P = 0·034), but not long-term mortality. Sensitivity analyses with adjustment for tumour stage did not change the results. CONCLUSION: Hospital teaching status was strongly related to decreased mortality in both the short and long term. This may relate to processes of care rather than volume per se. Very low-volume hospitals had the highest short-term mortality risk.

Assessing surgical quality: comparison of general and procedure-specific morbidity estimation models for the risk adjustment of pancreaticoduodenectomy outcomes.

INTRODUCTION: The use of outcomes to evaluate surgical quality implies the need for detailed risk adjustment. The physiological and operative severity score for the enumeration of mortality and morbidity (POSSUM) is a generally applicable risk adjustment model suitable for pancreatic surgery. A pancreaticoduodenectomy (PD)-specific intraoperative pancreatic risk assessment (IPRA) estimates the risk of postoperative pancreatic fistula (POPF) and associated morbidity based on factors that are not incorporated into POSSUM. OBJECTIVE: The aim of the study was to compare the risk estimations of POSSUM and IPRA in patients undergoing PD. METHODS: An observational single-center cohort study was conducted including 195 patients undergoing PD in 2008-2010. POSSUM and IPRA data were recorded prospectively. Incidence and severity of postoperative morbidity was recorded according to established definitions. The cohort was grouped by POSSUM and IPRA risk groups. The estimated and observed outcomes and morbidity profiles of POSSUM and IPRA were scrutinized. RESULTS: POSSUM-estimated risk (62 %) corresponded with observed total morbidity (65 %). Severe morbidity was 17 % and in-hospital-mortality 3.1 %. Individual and grouped POSSUM risk estimates did not reveal associations with incidence (p = 0.637) or severity (p = 0.321) of total morbidity or POPF. The IPRA model identified patients with high POPF risk (p < 0.001), but was even associated with incidence (p < 0.001) and severity (p < 0.001) of total morbidity. CONCLUSION: The risk factors defined by a PD-specific model were significantly stronger predictive indicators for the incidence and severity of postoperative morbidity than the factors incorporated in POSSUM. If available, reliable procedure-specific risk factors should be utilized in the risk adjustment of surgical outcomes. For pancreatic surgery, generally applicable tools such as POSSUM still have to prove their relevance.

Diagnostic value of abdominal drainage in individual risk assessment of pancreatic fistula following pancreaticoduodenectomy.

BACKGROUND: The use of prophylactic abdominal drainage following pancreaticoduodenectomy (PD) is controversial as its therapeutic value is uncertain. However, the diagnosis of postoperative pancreatic fistula (POPF), the main cause of PD-associated morbidity, is often based on drain pancreatic amylase (DPA) levels. The aim of this study was to assess the predictive value of DPA, plasma pancreatic amylase (PPA) and serum C-reactive protein (CRP) for diagnosing POPF after PD. METHODS: Patients undergoing PD with prophylactic drainage between 2008 and 2012 were studied prospectively. DPA, PPA and CRP levels were obtained daily. Differences between groups with clinically relevant POPF (International Study Group on Pancreatic Fistula (ISGPF) grade B/C) and without clinically relevant POPF (no POPF or ISGPF grade A) were evaluated. Receiver operating characteristic (ROC) analyses were performed to determine the value of DPA, PPA and CRP in prediction of POPF. Risk profiles for clinically relevant POPF were constructed and related to the intraoperative pancreatic risk assessment. RESULTS: Fifty-nine (18.7 per cent) of 315 patients developed clinically relevant POPF. DPA, PPA and CRP levels on postoperative day (POD) 1-3 differed significantly between the study groups. In predicting POPF, the DPA level on POD 1 (cut-off at 1322 units/l; odds ratio (OR) 24.61, 95 per cent confidence interval 11.55 to 52.42) and POD 2 (cut-off at 314 units/l; OR 35.45, 14.07 to 89.33) was superior to that of PPA on POD 1 (cut-off at 177 units/l; OR 13.67, 6.46 to 28.94) and POD 2 (cut-off at 98 units/l; OR 16.97, 8.33 to 34.59). When DPA was combined with CRP (cut-off on POD 3 at 202 mg/l; OR 16.98, 8.43 to 34.21), 90.3 per cent of postoperative courses could be predicted correctly (OR 44.14, 16.89 to 115.38). CONCLUSION: The combination of serum CRP and DPA adequately predicted the development of clinically relevant pancreatic fistula following PD.

Is quantitative PCR for the pneumolysin (ply) gene useful for detection of pneumococcal lower respiratory tract infection?

The pneumolysin (ply) gene is widely used as a target in PCR assays for Streptococcus pneumoniae in respiratory secretions. However, false-positive results with conventional ply-based PCR have been reported. The aim here was to study the performance of a quantitative ply-based PCR for the identification of pneumococcal lower respiratory tract infection (LRTI). In a prospective study, fibreoptic bronchoscopy was performed in 156 hospitalized adult patients with LRTI and 31 controls who underwent bronchoscopy because of suspicion of malignancy. Among the LRTI patients and controls, the quantitative ply-based PCR applied to bronchoalveolar lavage (BAL) fluid was positive at >or=10(3) genome copies/mL in 61% and 71% of the subjects, at >or=10(5) genome copies/mL in 40% and 58% of the subjects, and at >or=10(7) genome copies/mL in 15% and 3.2% of the subjects, respectively. Using BAL fluid culture, blood culture, and/or a urinary antigen test, S. pneumoniae was identified in 19 LRTI patients. As compared with these diagnostic methods used in combination, quantitative ply-based PCR showed sensitivities and specificities of 89% and 43% at a cut-off of 10(3) genome copies/mL, of 84% and 66% at a cut-off of 10(5) genome copies/mL, and of 53% and 90% at a cut-off of 10(7) genome copies/mL, respectively. In conclusion, a high cut-off with the quantitative ply-based PCR was required to reach acceptable specificity. However, as a high cut-off resulted in low sensitivity, quantitative ply-based PCR does not appear to be clinically useful. Quantitative PCR methods for S. pneumoniae using alternative gene targets should be evaluated.

Search for DNA of exogenous mouse mammary tumor virus-related virus in human breast cancer samples.

Earlier reports of a human exogenous retrovirus (HMTV) related closely to mouse mammary tumor virus (MMTV) led us to search for these viral sequences in breast cancer tissues and normal tissues. A real-time PCR was developed based on MMTV and published HMTV envelope sequences. The real-time PCR method can detect one to ten copies of MMTV target DNA. Tissue samples were collected prospectively from 18 breast cancer patients and 11 non-malignant control cases, as well as peripheral blood leukocytes from the same women. Despite the high sensitivity of the real-time PCR method used, none of the samples were positive for HMTV DNA or RNA. The absence of HMTV DNA in both breast cancer samples and controls indicates either that the concentration of putative HMTV DNA in the breast cancers was too low for detection or that it did not exist there.

Classification of highly similar crude oils using data sets from comprehensive two-dimensional gas chromatography and multivariate techniques.

Comprehensive two-dimensional gas chromatography (GCxGC) has proven to be an extremely powerful separation technique for the analysis of complex volatile mixtures. This separation power can be used to discriminate between highly similar samples. In this article we will describe the use of GCxGC for the discrimination of crude oils from different reservoirs within one oil field. These highly complex chromatograms contain about 6000 individual, quantified components. Unfortunately, small differences in most of these 6000 components characterize the difference between these reservoirs. For this reason, multivariate-analysis (MVA) techniques are required for finding chemical profiles describing the differences between the reservoirs. Unfortunately, such methods cannot discern between 'informative variables', or peaks describing differences between samples, and 'uninformative variables', or peaks not describing relevant differences. For this reason, variable selection techniques are required. A selection based on information between duplicate measurements was used. With this information, 292 peaks were used for building a discrimination model. Validation was performed using the ratio of the sum of distances between groups and the sum of distances within groups. This step resulted in the detection of an outlier, which could be traced to a production problem, which could be explained retrospectively.

Gas chromatographic methods for oil analysis.

In the past 50 years. gas chromatography (GC) has played a most important role in the analysis of oil. In this review, the early history is briefly reviewed; next developments in this highly relevant application area since about 1985 are highlighted. The main topic of interest are the introduction and decisive role of capillary GC, the use of selective detection techniques, the versatility of coupled-column techniques and, specifically, the additional power of comprehensive two-dimensional GC.

Human retrovirus type 5 sequences in non-Hodgkin's lymphoma of T cell origin.

DNA of a recently described fifth exogenous retrovirus (HRV-5) has been found in blood samples from patients with autoimmune diseases and lymphoma. We analyzed HRV-5 sequence in DNA extracted from whole blood of 17 patients with T cell non-Hodgkin's lymphoma (NHL) and 186 patients with hematological malignancies other than NHL, using a sensitive PCR technique. While all samples of patients with hematological malignancies other than NHL were negative, 2 of the 17 patients with T cell NHL were HRV-5 DNA positive. Both HRV-5-positive patients had T cell NHL of high-grade malignancy (stage IV) and diffuse distribution of the lymphoma, including infiltration of bone marrow or lung and pleura. The difference in HRV-5 DNA detection frequency between NHL and control groups is significant (p value of 0.0004 judged by the Fisher exact test). These data, together with our previous finding of HRV-5 DNA in three B cell NHL cases, are compatible with an association between HRV-5 and NHL, of both T cell and B cell origin.

Sequence evolution and cross-reactive antibody responses to hypervariable region 1 in acute hepatitis C virus infection.

Hepatitis C virus (HCV) infection may result in acute resolving or chronic infection. Patients that clear the infection have a more vigorous cellular immune response and an early humoral response to the hypervariable region 1 (HVR1) of the E2 envelope protein. To analyse further the properties of the early anti-HVR1 response, cross-reactivity of anti-HVR1 responses was assessed in five patients with acute HCV infection, who were infected by the same virus strain during a nosocomial outbreak. The sequence evolution of HVR1 was examined in sequential serum samples up to 37 months post infection. Peptides were synthesised corresponding to the obtained HVR1 sequences and unrelated HVR1 sequences, and antibody reactivity to the peptides in sequential sera was investigated by ELISA. The results suggest an association between specific gaps in humoral immunity and the HVR1 sequence evolution during early infection. Possible interpretations of this phenomenon include immune escape mechanisms or suppression of specific anti-HVR1 antibodies.

Identification of novel porcine endogenous betaretrovirus sequences in miniature swine.

PCR amplification of genomic DNA from miniature swine peripheral blood lymphocytes, using primers corresponding to highly conserved regions of the polymerase (pol) gene, allowed the identification of two novel porcine endogenous retrovirus (PERV) sequences, PMSN-1 and PMSN-4. Phylogenetic analyses of the nucleotide sequences of PMSN-1 and PMSN-4 revealed them to be most closely related to betaretroviruses. The identification of PERVs belonging to the Betaretrovirus genus shows that endogenous retroviruses of this family are more broadly represented in mammalian species than previously appreciated. Both sequences contained inactivating mutations, implying that these particular loci are defective. However, Southern blot analysis showed additional copies of closely related proviruses in the miniature swine genome. Analyses of fetal and adult miniature swine tissues revealed a broad mRNA expression pattern of both PMSN-1 and PMSN-4. The most abundant expression was detected in whole bone marrow c-kit(+) (CD117(+)) progenitor bone marrow cells, fetal liver, salivary gland, and thymus. It appears unlikely that functional loci encoding these novel PERV sequences exist, but this remains to be established. The betaretrovirus sequences described in this report will allow such investigations to be actively pursued.

Prevalence of blood-borne viral infections (cytomegalovirus, human herpesvirus-6, human herpesvirus-7, human herpesvirus-8, human T-cell lymphotropic virus-I/II, human retrovirus-5) among blood donors in Latvia.

The identification of blood-borne viral infections is important in transfusion medicine. The aim of this study was to evaluate the prevalence of human herpesvirus (HHV) [cytomegalovirus (CMV), HHV-6, HHV-7 HHV-8] and human retrovirus (HRV) (human T-cell lymphotropic virus (HTLV)-I/II, HRV-5) infections among apparently healthy Latvian blood donors. DNA extracted from peripheral blood leukocytes (PBL) of 150 individuals was tested for herpesviruses by sensitive polymerase chain reaction (PCR) technique. None of the blood donors was positive for HHV-8 infection, while the incidence of latent beta-herpesvirus infections was high: single infection by CMV, HHV-6, and HHV-7 was detected in 2.6%, 8.0%, and 43.3% of blood donors, respectively. Simultaneous dual and triple infections of these viruses were observed in 28.0% and 4.7% of individuals, respectively. Active infection by CMV and HHV-6 was not found, but HHV-7 DNA was present in plasma of 10.6% of the blood donors. While all blood donors were HTLV-II and HRV-5 negative, 4.6% of HTLV-I seronegative blood donors were positive for the HTLV-I tax gene, although none of them harbored sequences for structural genes of the provirus. Based on our results, we conclude that monitoring of beta-herpesvirus infections in blood donors can be important in cases of transfusions to immunocompromised persons. HHV-8, as well as the retroviruses HTLV-II and HRV-5, were not found in blood of Latvian blood donors. More investigations are required to explain the presence of the HTLV-I tax sequence in seronegative blood donors.

Increased immunoglobulin G, but not M, binding to endogenous retroviral antigens in HIV-1 infected persons.

The modes of interaction between products of human endogenous retroviral (HERV) sequences and the immune system are largely unknown. In HIV infected persons, an exogenous retrovirus adds further complexity to the situation. Therefore, 14 synthetic peptides with sequences derived from conserved regions of various endogenous retroviruses (ERVs) and from related exogenous retroviruses were used to search for IgG and IgM antibodies that bind to such antigens in 15 HIV-1 seropositive and 17 seronegative immunosuppressed patients. IgG binding to three peptides, namely, the C-terminal half of murine leukemia virus (MLV) capsid protein, the conserved portion of HERV-H transmembrane protein, and the Pol region of human mouse mammary tumor virus (MMTV)-like (HML3) sequence, was observed in both groups. Binding was, however, more frequent and more firm in HIV-1 positive samples (P<0.0001, Wilcoxon rank sum test). IgM binding to the same peptides showed no significant differentiation between the two groups of patients. Binding to both immunoglobulin isotypes was sometimes variable over time in both groups. No correlation of either IgG or IgM peptide binding with progression to AIDS in HIV-1 infected individuals was observed. Inhibition studies using analogous endogenous and exogenous retroviral peptides, including HIV-1, demonstrated specificity of the IgG antibodies for a narrow range of MLV- and MMTV-like retroviral antigens, and excluded cross-reactivity of antibodies to HIV-1 as a cause of these observations. Thus, unlike IgG, IgM binding to retroviral antigens was ubiquitous. It is suggested that anti-HERV IgM belong to a class of natural antibodies and might serve as primers in the mediation of humoral immune responses to more or less related exogenous retroviruses. Increased IgG binding in HIV-1 infected individuals could result from such priming, or reflect higher HERV antigen expression.

Comparison of comprehensive two-dimensional gas chromatography and gas chromatography--mass spectrometry for the characterization of complex hydrocarbon mixtures.

In this paper, we compare the current separation power of comprehensive two-dimensional gas chromatography (GCxGC) with the potential separation power of GC-mass spectrometry (GC-MS) systems. Using simulated data, we may envisage a GC-MS contour plot, that can be compared with a GCxGC chromatogram. Real examples are used to demonstrate the current potential of the two techniques in the field of hydrocarbon analysis. As a separation technique for complex hydrocarbon mixtures, GCxGC is currently about as powerful as GC-MS is potentially powerful. GC-MS has not reached its potential separation power in this area, because a universal, soft ionization method does not exist. The greatest advantage of GCxGC is, however, its potential for quantitative analysis. Because flame-ionisation detection can be used, quantitative analysis by GCxGC is much more robust, reliable and reproducible.

[Newly discovered human retroviruses. Association with disease is still undetermined]. / Nyupptäckta humana retrovirus. Association till sjukdom är ännu oklar.

Retroviruses are enveloped RNA viruses which can transcribe RNA to DNA and integrate into the chromosomal DNA of their host cell. Heritable integrations give rise to endogenous retroviral sequences (ERVs). The rest is exogenous, infecting from individual to individual. This survey highlights an emerging scenario in human retrovirology. Humans have thousands of distinct ERVs. Although most are damaged by mutations, many are expressed as RNA, a few also as proteins and viral particles. The latter are not known to be infectious. Obviously, human ancestors encountered many different exogenous retroviruses, some of which may still be extant. In fact, an exogenous retrovirus related to ERVs was recently discovered. It is the fifth human exogenous retrovirus, human retrovirus 5 (HRV-5). It succeeds the two human T-lymphotropic viruses (HTLVs) and the two human immunodeficiency viruses (HIVs). The newly discovered endogenous and exogenous human retroviruses are now being investigated for association with disease. There are indications of selective ERV activation in multiple sclerosis, schizophrenia and seminoma. HRV-5 has been associated with rheumatoid arthritis, systemic lupus erythematosus and non-Hodgkin lymphoma. It is not yet known whether these first observations signal a pathogenic role for the newly discovered retroviruses.

Structural prerequisites for intersubtype B and D antigenicity of the third variable envelope region (V3) of human immunodeficiency virus type 1.

To elucidate the structural requirements for intersubtype antigenicity of human immunodeficiency virus type 1 (HIV-1) third variable envelope region (V3), synthetic peptides were used in enzyme immunoassays (EIAs) with serum samples from persons with proven or probable subtype B and D infections. Mathematical analyses of results from EIAs with singly substituted V3 peptides revealed important residues determining overall N-terminal V3 peptide antigenicity. This information was used to design V3 immunogens, rabbit antiserum to which were tested in EIA and for in vitro neutralization of molecular clones of HIV-1(MN) and HIV-1(MAL). Intersubtype-reactive epitopes were distributed toward the N-terminal half of the V3 loop. Lysine at position 310, arginine at position 311, and isoleucine at position 314, all derived from the MN primary sequence, were major determinants of intersubtype V3 antigenicity. Combinations of residues that enhanced antigenicity often contained lysine at position 310. Threonine at position 308 was common in the least advantageous combinations. V3 immunogens modified to achieve optimal antigenicity induced antiserum with augmented cross-neutralization of virus from MAL and MN molecular clones, suggesting one approach to subunit vaccine development.

Human retrovirus 5 sequences in peripheral blood cells of patients with B-cell non-Hodgkin's lymphoma.

A recently described sequence from a probable 5th human exogenous retrovirus, HRV-5, is related to type A, B and D retroviruses. It was initially detected in a salivary gland biopsy from a patient with Sjögren's syndrome, but it is not consistently associated with this disease. We searched for the HRV-5 sequence in DNA extracted from whole blood of 300 blood donors, 81 patients with hematological malignancy and 21 patients with neurological disease using PCR. While samples from none of the blood donors and the neurological patients became positive, 3 of the 81 patients with hematological malignancy were HRV-5 DNA positive. All 3 had B-cell non-Hodgkin's lymphoma of low grade. The difference in frequency between NHL and controls is statistically significant. HRV-5 DNA was found in DNA from whole blood and in plastic-adherent cells but not in tumor cell DNA. Thus, monocytes/macrophages may be preferred targets for HRV-5. Our result, together with a previous finding of HRV-5 DNA in 2 NHL cases, is compatible with an association between HRV-5 and NHL, whether causal or not.