Detection of in vivo hepatitis B virus surface antigen mutations-A comparison of four routine screening assays.

An important requirement for a state-of-the-art hepatitis B surface antigen (HBsAg) screening assay is reliable detection of mutated HBsAg. Currently, there is a striking shortage of data regarding the detection rates of in vivo HBsAg mutations for these clinically important assays. Therefore, we compared the detection rates of four commercial HBsAg screening assays using a global cohort of 1553 patients from four continents with known HBV genotypes. These samples, which represent the broadest spectrum of known and novel HBsAg major hydrophilic region (MHR) mutations to date, were analyzed for the presence of HBsAg using the Roche Elecsys® HBsAg II Qualitative, Siemens ADVIA Centaur XP HBsAg II, Abbott Architect HBsAg Qualitative II and DiaSorin Liaison® HBsAg Qualitative assays, respectively. Of the 1553 samples, 1391 samples could be sequenced; of these, 1013 (72.8%) carried at least one of the 345 currently known amino acid substitutions (distinct HBsAg mutation) in the HBsAg MHR. All 1553 patient samples were positive for HBsAg using the Elecsys® HBsAg II Qual assay, with a sensitivity (95% confidence interval) of 99.94% (99.64%-100%), followed by the Abbott Architect 99.81% (99.44%-99.96%), Siemens ADVIA 99.81% (99.44%-99.96%) and DiaSorin Liaison® 99.36% (98.82%-99.69%) assays, respectively. Our results indicate that the Elecsys® HBsAg II Qual assay exhibits the highest sensitivity among the commercial HBsAg screening assays, and demonstrate that its capacity to detect HBV infection is not compromised by HBsAg MHR mutants.

Nonequilibrium molecular dynamics simulations of nanoconfined fluids at solid-liquid interfaces.

We investigate the hydrodynamic properties of a Lennard-Jones fluid confined to a nanochannel using molecular dynamics simulations. For channels of different widths and hydrophilic-hydrophobic surface wetting properties, profiles of the fluid density, stress, and viscosity across the channel are obtained and analysed. In particular, we propose a linear relationship between the density and viscosity in confined and strongly inhomogeneous nanofluidic flows. The range of validity of this relationship is explored in the context of coarse grained models such as dynamic density functional-theory.

The distribution of KIR-HLA functional blocks is different from north to south of Italy.

The killer cell immunoglobulin-like receptor (KIR)-human leukocyte antigen (HLA) interaction represents an example of genetic epistasis, where the concomitant presence of specific genes or alleles encoding receptor-ligand units is necessary for the activity of natural killer (NK) cells. Although KIR and HLA genes segregate independently, they co-evolved under environmental pressures to maintain particular KIR-HLA functional blocks for species survival. We investigated, in 270 Italian healthy individuals, the distribution of KIR and HLA polymorphisms in three climatic areas (from cold north to warm south), to verify their possible geographical stratification. We analyzed the presence of 13 KIR genes and genotyped KIR ligands belonging to HLA class I: HLA-C, HLA-B and HLA-A. We did not observe any genetic stratification for KIR genes and HLA-C ligands in Italy. By contrast, in a north-to-south direction, we found a decreasing trend for the HLA-A3 and HLA-A11 ligands (P = 0.012) and an increasing trend for the HLA-B ligands carrying the Bw4 epitope (P = 0.0003) and the Bw4 Ile80 epitope (P = 0.0005). The HLA-A and HLA-B KIR ligands were in negative linkage disequilibrium (correlation coefficient -0.1211), possibly as a consequence of their similar function in inhibiting NK cells. The distribution of the KIR-HLA functional blocks was different along Italy, as we observed a north-to-south ascending trend for KIR3DL1, when coupled with HLA-B Bw4 ligands (P = 0.0067) and with HLA-B Bw4 Ile80 (P = 0.0027), and a descending trend for KIR3DL2 when coupled with HLA-A3 and HLA-A11 ligands (P = 0.0044). Overall, people from South Italy preferentially use the KIR3DL1-HLA-B Bw4 functional unit, while those from the North Italy equally use both the KIR3DL2-HLA-A3/A11 and the KIR3DL1-HLA-B Bw4 functional units to fight infections. Thus, only KIR3DL receptors, which exert the unique role of microbial sensors through the specific D0 domain, and their cognate HLA-A and HLA-B ligands are selectively pressured in Italy according to geographical north-to-south distribution.

Acute hepatitis C: clinical and laboratory diagnosis, course of the disease, treatment.

INTRODUCTION: Acute hepatitis C (AHC) is asymptomatic in about 70-80 % of cases and, therefore, is usually undiagnosed. Although the clinical course is typically mild, AHC has a high rate of transition to chronicity. MATERIAL AND METHODS: We evaluated the literature data concerning risk factors for HCV transmission, diagnosis, natural history, and antiviral treatment of AHC. RESULTS: Although new methods have been developed, anti-HCV seroconversion remains the gold standard for the diagnosis of AHC. This phenomenon, however, is identifiable in less than half of cases in the everyday clinical practice, since most AHC patients do not know their previous anti-HCV/HCV-RNA status. An early short-term interferon treatment in AHC patients prevents progression to chronicity in most of treated patients. CONCLUSION: The literature data give evidence of the clinical relevance of an early diagnosis of AHC for an early short-term interferon treatment. There is also the suggestion to use newly developed laboratory methods to distinguish AHC from an acute exacerbation of a chronic HCV infection.

Interleukin-4RA gene polymorphism is associated with oral mucous membrane pemphigoid.

OBJECTIVE: The aim of this study was to analyse whether the polymorphisms of several pro- and anti-inflammatory cytokines may influence the susceptibility to predominantly oral Mucous membrane pemphigoid (MMP) in a Northern Italian population. MATERIAL AND METHODS: DNA was obtained from 41 MMP patients (29 with exclusively oral pemphigoid [OP]) and 140 unrelated bone marrow donors. Thirteen cytokine genes with 22 single-nucleotide polymorphisms (SNP) were studied by a sequence-specific PCR assay. RESULTS: There was no significant difference between the patients taken together and healthy controls for any cytokine gene polymorphism studied. However, the allele A of the IL-4 receptor A (IL-4RA) was significantly more frequent in OP than controls (P < 0.05), causing an increased frequency of genotype A/A in OP patients (89.7 vs. 67.9, odds ratio: 4.11, 95% confidence intervals 1.18-14.28, P = 0.023, Pc = 0.046). CONCLUSION: IL-4RA-1902 A/A genotype has been associated with a reduced response to IL-4 and has been found in 90% OP patient. Giving the supposed importance of IL-4 in MMP fibrotic process, our results can partially explain the low likelihood of scarring in OP patients.

Minor H antigen matches and mismatches are equally distributed among recipients with or without complications after HLA identical sibling renal transplantation.

Studies of the effect of minor H antigen mismatching on the outcome of renal transplantation are scarce and concern mainly single center studies. The International Histocompatibility and Immunogenetics Workshops (IHIW) provide a collaborative platform to execute crucial large studies. In collaboration with 16 laboratories of the IHIW, the role of 15 autosomal, 10 Y-chromosome encoded minor H antigens and 3 CD31 polymorphisms, was investigated in relation to the incidence of renal graft rejection and graft loss in 444 human leukocyte antigens (HLA)-identical sibling renal transplantations. Recipient and donor DNA samples were genotyped for the minor H antigens HA-1, HA-2, HA-3, HA-8, HB-1, ACC-1, ACC-2, SP110, PANE1, UGT2B17, C19Orf48, LB-ECGF-1, CTSH, LRH-1, LB-ADIR and HY. The correlation between minor H antigen mismatch and the primary outcome graft rejection or graft loss was statistically analyzed. The incidence of rejection was very low and no correlation was observed between one or more minor H antigen mismatch(es) and a rejection episode (n = 36), of which only eight resulted in graft loss. In summary, in our study cohort of 444 renal transplants, mismatching for neither autosomal nor HY minor H antigens correlate with rejection episodes or with graft loss.

Hepatitis B and immigrants: a SIMIT multicenter cross-sectional study.

BACKGROUND: The continuing migration of individuals from geographic areas with high/medium endemicity has determined the arrival of new chronic hepatitis B virus (HBV) carriers in Italy. The magnitude of this phenomenon and clinical/virological features of HBsAg-positive migrants remain not very well defined. AIMS: To evaluate the proportion of HBsAg-positive immigrants enrolled in this multicenter Società Italiana di Malattie Infettive e Tropicali (SIMIT) cross-sectional study and to compare the characteristics of chronic hepatitis B infection in migrants to those of Italian carriers. METHODS: From February 1 to July 31 2008, anonymous data were obtained from all HBsAg-positive patients aged ≥ 18 years observed at 74 Italian centers of infectious diseases. RESULTS: Of the 3,760 HBsAg-positive subjects enrolled, 932 (24.8 %) were immigrants, with a prevalent distribution in central to northern Italy. The areas of origin were: Far East (37.1 %), Eastern Europe (35.4 %), Sub-Saharan Africa (17.5 %), North Africa (5.5 %), and 4.5 % from various other sites. Compared to Italian carriers, migrants were significantly younger (median age 34 vs. 52 years), predominantly female (57.5 vs. 31 %), and most often at first observation (incident cases 34.2 vs. 13.3 %). HBeAg-positives were more frequent among migrants (27.5 vs. 14 %). Genotype D, found in 87.8 % of Italian carriers, was present in only 40 % of migrants, who were more frequently inactive HBV carriers, with a lower prevalence of chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). Only 27.1 % of migrants received antiviral treatment compared to 50.3 % of Italians. CONCLUSIONS: Twenty-five percent of all HBV carriers examined at Italian centers was composed of immigrants with demographic, serological, and virological characteristics that differed from those of natives and appeared to have an inferior access to treatment.

Is there a role for adjuvant therapy in radiation-induced angiosarcoma of the breast? A case report and review of the literature.

BACKGROUND: Angiosarcoma (AS) of the breast is very rare, accounting for 1% of all soft tissue breast tumors. AS may present as primary tumors of the breast or as secondary lesions usually associated with previous radiotherapy. Commonly, secondary AS affects older women (median age 67-71 years) with a clinical history of breast cancer. The preferred site of onset of RIAS is the edge of radiation fields, where radiation doses and tumor necrosis may be heterogeneous, resulting in a DNA damage and instability. Radical surgery is the treatment of choice, but no clear consensus exists on surgical management of breast AS. CASE REPORT: We describe an atypical case of relapsed RIAS after radical mastectomy, treated with new surgery and, considering the higher risk of recurrence, subsequent adjuvant chemotherapy with weekly paclitaxel. CONCLUSIONS: The frequency of radiation-induced angiosarcomas (RIAS) after breast-conserving surgery and radiotherapy has been increased to 0.14-0.5% among long survivors. Nevertheless, even if RIAS continues to be prognostically an extremely unfavorable cancer due to a high rate of recurrence, distant spread, and median overall survival (OS) of about 60 months, the benefits of loco-regional breast radiotherapy are clearly higher than the risk in developing angiosarcoma.

Neurodevelopmental assessment of infants born to mothers with hypertensive disorder of pregnancy at six months of age.

Infant neurodevelopment is a complex process which may be affected by different events during pregnancy, such as hypertensive disorders of pregnancy (HDP). We conducted a prospective cohort study to compare the prevalence of neurodevelopmental disorders in infants born to mothers with and without HDP at six months of age. Participants attended the Health Observatory of Instituto de Desarrollo e Investigaciones Pediátricas "Prof. Dr. Fernando E. Viteri" during 2018 and 2019. Infant neurodevelopment was assessed with the Bayley Scales of Infant and Toddler Development-Third Edition (Bayley-III). Data were analyzed using Chi-square, Student's t-test and Mann-Whitney test. Of the 132 participating infants, 68 and 64 were born to mothers with and without HDP, respectively. At six months, the prevalence of risk of neurodevelopmental delay was significantly higher in infants born to mothers with than without HDP (27.9% vs. 9.4%; p = 0.008) (odds ratio, 3.71; 95% confidence interval, 1.30; 12.28). In conclusion, infants born to mothers with HDP had three times increased risk of neurodevelopmental delay at six months of age.

Management of systemic prostate cancer: current algorithm from castration sensitive to castration resistant setting.

In recent years, the advanced knowledge of clinical, biological and molecular features of prostate cancer have led to the introduction of new drugs and have allowed the relocation of old drugs in different settings. In this way, the new concepts of systemic disease arise: high risk or high volume vs. low risk and low volume disease castration sensitive prostate cancer (CSPC), diversifying the use of previously approved drugs (CRPC) and opening new scenarios for sequence therapy. The aim of this review is to integrate new developments into the medical management of systemic prostate cancer.

Sorafenib in combination with erlotinib or with gemcitabine in elderly patients with advanced non-small-cell lung cancer: a randomized phase II study.

BACKGROUND: Sorafenib is a small-molecule multitargeted kinase inhibitor that blocks the activation of C-RAF, B-RAF, c-KIT, FLT-3, RET, vascular endothelial growth factor receptor 2 (VEGFR-2), VEGFR-3 and platelet-derived growth factor receptor ß. The aim of this multicenter, randomized phase II study was to evaluate clinical activity and safety of sorafenib in combination with erlotinib or gemcitabine in unselected untreated elderly patients with non-small-cell lung cancer (NSCLC). METHODS: The trial was designed to select the most promising sorafenib-containing combination in previously untreated elderly (≥70 years) stage IIIB or IV NSCLC patients, with performance status of zero to two. Patients were randomly assigned to one of the following combinations: gemcitabine, 1200 mg/m(2) days 1 and 8, every 21 days, for a maximum of six cycles, plus sorafenib, 800 mg/day, until disease progression or unacceptable toxicity (arm 1); or erlotinib, 150 mg/day, plus sorafenib, 800 mg/day, until disease progression or unacceptable toxicity (arm 2). A selection design was applied with 1-year survival rate as the primary end point of the study, requiring 58 patients. RESULTS: Sixty patients were randomly allocated to the study (31 patients in arm 1 and 29 patients in arm 2). After a median follow-up of 15 months, 10 patients [32%, 95% confidence interval (CI) 16% to 49%] in arm 1 and 13 patients (45%, 95% CI 27% to 63%) in arm 2 were alive at 1 year. Median overall survival was 6.6 and 12.6 months in arm 1 and arm 2, respectively. Observed toxic effects were consistent with the expected drug profiles. CONCLUSIONS: The combination of erlotinib and sorafenib was feasible in elderly patients with advanced NSCLC and was associated with a higher 1-year survival rate than the other arm. According to the selection design, this combination warrants further investigation in phase III trials.

Diagnostic Salivary Tests for SARS-CoV-2.

The diagnosis of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection relies on the detection of viral RNA by real-time reverse transcription polymerase chain reaction (rRT-PCR) performed with respiratory specimens, especially nasopharyngeal swabs. However, this procedure requires specialized medical personnel, centralized laboratory facilities, and time to provide results (from several hours up to 1 d). In addition, there is a non-negligible risk of viral transmission for the operator who performs the procedure. For these reasons, several studies have suggested the use of other body fluids, including saliva, for the detection of SARS-CoV-2. The use of saliva as a diagnostic specimen has numerous advantages: it is easily self-collected by the patient with almost no discomfort, it does not require specialized health care personnel for its management, and it reduces the risks for the operator. In the past few months, several scientific papers, media, and companies have announced the development of new salivary tests to detect SARS-CoV-2 infection. Posterior oropharyngeal saliva should be distinguished from oral saliva, since the former is a part of respiratory secretions, while the latter is produced by the salivary glands, which are outside the respiratory tract. Saliva can be analyzed through standard (rRT-PCR) or rapid molecular biology tests (direct rRT-PCR without extraction), although, in a hospital setting, these procedures may be performed only in addition to nasopharyngeal swabs to minimize the incidence of false-negative results. Conversely, the promising role of saliva in the diagnosis of SARS-CoV-2 infection is highlighted by the emergence of point-of-care technologies and, most important, point-of-need devices. Indeed, these devices can be directly used in workplaces, airports, schools, cinemas, and shopping centers. An example is the recently described Rapid Salivary Test, an antigen test based on the lateral flow assay, which detects the presence of the virus by identifying the spike protein in the saliva within a few minutes.

HLA-class I markers and multiple sclerosis susceptibility in the Italian population.

Previous studies reported an association with multiple sclerosis (MS) of distinct HLA-class I markers, namely HLA-A*02, HLA-Cw*05 and MOG-142L. In this work, we tested the association with MS of A*02 and Cw*05 in 1273 Italian MS patients and 1075 matched controls, which were previously analyzed for MOG-142, and explored the relationship among these three markers in modulating MS risk. HLA-A*02 conferred a statistically robust MS protection (odds ratio, OR=0.61; 95% confidence intervals, CI=0.51-0.72, P<10(-9)), which was independent of DRB1*15 and of any other DRB1* allele and remained similar after accounting for the other two analyzed class I markers. Conversely, the protective effect we previously observed for MOG-142L was secondary to its linkage disequilibrium with A*02. Cw*05 was not associated considering the whole sample, but its presence significantly enhanced the protection in the HLA-A*02-positive group, independently of DRB1: the OR conferred by A*02 in Cw*05-positive individuals (0.22, 95% CI=0.13-0.38) was significantly lower than in Cw*05-negative individuals (0.69, 95% CI=0.58-0.83) with a significant (P=4.94 x 10(-5)) multiplicative interaction between the two markers. In the absence of A*02, Cw*05 behaved as a risk factor, particularly in combination with DRB1*03 (OR=3.89, P=0.0006), indicating that Cw*05 might be a marker of protective or risk haplotypes, respectively.

Efficacy and safety of a new immunoglobulin G product, Gammaplex(®), in primary immunodeficiency diseases.

This open-label multi-centre study evaluated a new intravenous immunoglobulin, Gammaplex®, in the treatment of 50 patients with primary immunodeficiency and significant hypogammglobulinaemia. Patients treated previously with other intravenous immunoglobulins received Gammaplex® on their same infusion schedule for 1 year; 22 were on a 21-day and 28 on a 28-day regimen (300-800 mg/kg/infusion). There were no serious, acute bacterial infections, whereas six subjects (12·0%) had at least one such infection in the 6 months before enrollment. Forty subjects (80·0%) had at least one non-serious infection; the median number of infective episodes per subject per year was 3·07. Antibiotics were taken by 38 subjects therapeutically and prophylactically by 16 at some time. Fewer than half (46·0%) missed any time off work or school because of infection or other illness. Trough immunoglobulin (Ig)G levels were above 6·00 g/l in all subjects at all assessments after 15 weeks with two exceptions. Overall, 21·2% of infusions were associated with an adverse event up to 72 h after infusion. The frequency of adverse events increased with infusion rate. Headache was the most common product-related adverse event (7·5% of 703 infusions). In conclusion, Gammaplex® is effective in primary immunodeficiency and is well tolerated.

Evolution of fungemia in an Italian region.

BACKGROUND: Fungemia represents a public health concern. Knowing aetiology and activity of the antifungals is critical for the management of bloodstream infections. Therefore, surveillance on local/international levels is desirable for a prompt administration of appropriate therapy. METHODS: Data on fungi responsible for fungemia and antifungal susceptibility profiles were collected from a laboratory-based surveillance over 2016-2017 in 12 hospitals located in Lombardia, Italy. The trend of this infection in twenty years was analysed. RESULTS: A total of 1024 episodes were evaluated. Rate of candiaemia progressively increased up to 1.46/1000 admissions. C.albicans was the most common species (52%), followed by C. parapsilosis (15%) and C glabrata (13%). As in the previous surveys the antifungal resistance is rare (echinocandins<2%, fluconazole 6%, amphotericin B 0.6%). Fungi other than Candida were responsible for 18 episodes: Cryptococcus neoformans (5 cases), Fusarium spp. (4), Magnusiomyces clavatus (3), Saccharomyces cerevisiae (3), Rhodotorula spp. (2), Exophiala dermatitidis (1). All fungi, except S.cerevisiae, were intrinsically resistant to echinocandins. Some isolates showed also elevated azole MIC. CONCLUSIONS: No particular changes in terms of species distribution and antifungal susceptibility patterns was noted. However, surveillance programs are needed to monitor trends in antifungal resistance, steer stewardship activities, orient empirical treatment.

Characterization of the c.190T>C missense mutation in BRCA1 codon 64 (Cys64Arg).

In the Milan area (Northern Italy), we identified a family characterized by a high prevalence of ovarian and breast cancer cases (5 out of 6 subjects, over 3 generations), and a predominant prevalence of ovarian lesions (4 out of 5 patients). Analysis of BRCA1 and BRCA2 genes allowed the identification of the missense c.190T>C mutation in codon 64 (Cys64Arg) of BRCA1. The aims of the present investigation were to characterize the functional implications of the c.190T>C mutation at the molecular level, and to search whether additional polymorphisms might be linked to the peculiar phenotypic features observed in the Italian pedigree. Molecular modelling studies suggested that substitution of the cysteine 64 with an arginine likely disrupts the architecture of the BRCA1 RING finger domain, responsible for the interaction with BARD1, essential for the tumor-suppressor activity of the BRCA1-BARD1 complex. By splicing site information analysis, exonic splicing enhancer site characterization, and analysis of transcript fragment length and sequence, we showed that the c.190T>C mutation was able to modulate the splicing of exon 5 in a fashion opposite to the c.190T>G transversion, responsible for the functionally-related Cys64Gly amino acid substitution. Genotyping of BRCA1 and BRCA2 in the Italian family revealed the presence of two significant polymorphisms: the cancer-associated c.2612C>T SNP in BRCA1, and the c.-26G>A SNP in the BRCA2 gene, acting as an ovarian cancer risk modifier in carriers of deleterious BRCA1 mutations. Analysis of these SNPs in a genotypically-unrelated Polish family, characterized by prevalent breast neoplasms in carriers of the c.190T>C mutation, revealed a genetic profile consistent with the hypothetic role of both polymorphisms.

Resistance mechanisms of tumour cells to EGFR inhibitors.

In spite of the overexpression and efficient inhibition of epidermal growth factor receptor (EGFR), resistance to EGFR inhibitors, monoclonal antibodies and tyrosine kinase inhibitors may occur. Understanding the molecular mechanisms affecting cancer cell sensitivity or resistance to EGFR inhibitors may be of help in deciding on treatment and in new translational studies. This review will focus on the most relevant mechanisms contributing to the acquisition of sensitivity/resistance to EGFR inhibitors.

Serum vascular endothelial growth factor (VEGF) levels correlate with tumor VEGF and p53 overexpression in endocrine positive primary breast cancer.

Vascular endothelial growth factor (VEGF) is a potent stimulator of angiogenesis, associated with unfavorable clinical characteristics in breast cancer. The aim of this study was to evaluate different angiogenic markers in endocrine-positive breast cancer patients. The authors analyzed serum and tumor samples from 71 patients with endocrine-positive operable primary breast cancer to determine the expression and the possible relationship between circulating serum VEGF levels, tumor VEGF expression, microvessel density (MVD), and other immunohistochemical parameters. Basal VEGF serum levels were significantly higher in breast cancer patients than in healthy controls. A significant correlation was observed between basal VEGF serum concentrations, microvessel density (p = 0.01) and p53 status (p = 0.004). Intratumoral VEGF expression was significantly associated with neoplastic embolization (p = 0.041) and circulating VEGF levels (p = 0.047). The results confirm that in primary endocrine-positive breast cancer serum VEGF levels are elevated and show a positive relationship with tumor VEGF and p53 overexpression.

Increased expression of the interleukin 1 receptor on blood neutrophils of humans with the sepsis syndrome.

Because of the potential importance of interleukin 1 (IL-1) in modulating inflammation and the observations that human blood neutrophils (PMN) express IL-1 receptors (IL-1R) and synthesize IL-1 alpha and IL-1 beta, we studied the IL-1R on blood PMN from a group of patients with the sepsis syndrome. We report a marked enhancement in the sites per cell of IL-1R expressed on sepsis-PMN of 25 consecutively studied patients compared to 20 controls (patient mean = 9,329 +/- 2,212 SE; control mean = 716 +/- 42 SE, respectively). There was no demonstrable difference in the Kd of IL-1R on sepsis-PMN (approximately 1 nM) as determined by saturation curves of 125I-IL-1 alpha binding and the IL-1R on sepsis-PMN had an apparent Mr approximately 68,000, a value like that of normal PMN. Cytofluorographic analysis indicated that the sepsis-PMN phenotype is a single homogeneous population with respect to IL-1R expression. In contrast, expression of the membrane complement receptor CR3 is not increased on sepsis-PMN. Similar increases in expression of IL-1R were not observed in various other inflammatory processes, including acute disseminated inflammation and organ failure not caused by infection, acute infection without organ failure, and immunopathologies such as active systemic lupus erythematosus and rheumatoid arthritis. Enhanced expression of IL-1R was not related simply to the state of myeloid stimulation. Increased expression of IL-1R on normal PMN was induced in vitro by incubating cells with recombinant human granulocyte-macrophage/colony-stimulating factor for 18 h and this response was inhibited by cycloheximide, suggesting the possibility that de novo synthesis of IL-1R might occur in PMN during the sepsis syndrome.

A unique recombination event resulting in a C4A*Q0,C4B*Q0 double null haplotype.

The fourth component of complement (C4) is encoded by two closely linked genes (C4A and C4B) within the MHC. Null alleles at either locus (C4AQ0 or C4BQ0) are relatively common, occurring at the C4A locus in approximately 10% of normal individuals and at the C4B locus in approximately 16% of normal individuals. However, the presence of the double null haplotype (C4A*Q0,B*Q0) on the same chromosome is extremely rare. We recently studied a 7-yr-old patient with recurrent sinopulmonary infections in whom we documented the mechanism by which the C4A*Q0,B*Q0 double null haplotype arose. Evaluation revealed significantly reduced levels of both C4 antigen and C4 hemolytic activity. Analysis of extended haplotypes in the family was performed using MHC typing and genomic DNA analysis. The patient was found to have a C4A*3,B*Q0 haplotype and a C4A*Q0,B*Q0 haplotype. The C4A*3,B*Q0 haplotype was contributed by the father. The mother possessed a C4A*Q0,B*1 haplotype and a C4A*3,B*1 haplotype. The first maternal haplotype was involved in a recombination event within the C4B locus on her other chromosome and resulted in a new C4B*Q0 null allele and the patient's C4A*Q0,B*Q0 haplotype. Segregation analysis mapped the recombination to a region 3' to the unique 6.4-kb TaqI restriction fragment of the maternal C4B locus. This is the first demonstration of a recombination event producing a C4 double null haplotype.