From delay to diagnosis: Chronic invasive fungal rhinosinusitis presenting with facial and orbital complications

Key Clinical Message

Early identification and management of chronic invasive fungal rhinosinusitis (CIFRS) is key to optimizing outcomes. A missed diagnosis can result in permanent vision loss, chronic facial pain, or death. We present a case of CIFRS and literature review.

Abstract

This case report presents a 56-year-old female with CIFRS involving orbital and facial complications. The patient experienced delayed diagnosis despite multiple ED visits for sinusitis with progressive facial pain and ocular deficits not alleviated with antibiotics, emphasizing the importance of early identification and maintaining high clinical suspicion for CIFRS. Prompt recognition, initiation of antifungal therapy, and aggressive surgical debridement were crucial for preventing disease progression and improving the patient's quality of life.

IgM Warm Autoantibodies Causing Autoimmune Hemolytic Anemia in a Pediatric Patient

Most often, IgM-mediated autoimmune hemolytic anemia (AIHA) presents as cold agglutinin disease in the pediatric population. The IgM warm agglutinins are rare, with few reports in the literature. This case study describes a 5 year old girl with nausea, abdominal pain and jaundice, and a hemoglobin of 5.5 g/dL who was diagnosed with a warm reactive IgM AIHA. The laboratory workup revealed a pan-reactive antibody and a direct antiglobulin test negative for IgG and C3. A thermal amplitude assay revealed reactive IgM antibodies at 37°C, 30°C, 25°C, and 4°C and an antibody titer of 1:8. An adsorption for IgM-specific autoantibodies exposed underlying anti-E and anti-Cw alloantibodies. Transfusion of phenotypically matched red blood cell units supported ongoing hemolysis. The AIHA treatment included steroids followed by rituximab with complete resolution. A literature review shows variable outcomes for warm AIHA in the pediatric population and often describes the presence of warm reactive IgM-mediated AIHA as an indicator for poor prognosis.

LncRNAs in HCV Infection and HCV-Related Liver Disease

Long non-coding RNAs (lncRNAs) are transcripts with poor coding capacity that may interact with proteins, DNA, or other RNAs to perform structural and regulatory functions. The lncRNA transcriptome changes significantly in most diseases, including cancer and viral infections. In this review, we summarize the functional implications of lncRNA-deregulation after infection with hepatitis C virus (HCV). HCV leads to chronic infection in many patients that may progress to liver cirrhosis and hepatocellular carcinoma (HCC). Most lncRNAs deregulated in infected cells that have been described function to potentiate or block the antiviral response and, therefore, they have a great impact on HCV viral replication. In addition, several lncRNAs upregulated by the infection contribute to viral release. Finally, many lncRNAs have been described as deregulated in HCV-related HCC that function to enhance cell survival, proliferation, and tumor progression by different mechanisms. Interestingly, some HCV-related HCC lncRNAs can be detected in bodily fluids, and there is great hope that they could be used as biomarkers to predict cancer initiation, progression, tumor burden, response to treatment, resistance to therapy, or tumor recurrence. Finally, there is high confidence that lncRNAs could also be used to improve the suboptimal long-term outcomes of current HCC treatment options.

AAV-mediated in vivo knockdown of luciferase using combinatorial RNAi and U1i

RNA interference (RNAi) has been successfully employed for specific inhibition of gene expression; however, safety and delivery of RNAi remain critical issues. We investigated the combinatorial use of RNAi and U1 interference (U1i). U1i is a gene-silencing technique that acts on the pre-mRNA by preventing polyadenylation. RNAi and U1i have distinct mechanisms of action in different cellular compartments and their combined effect allows usage of minimal doses, thereby avoiding toxicity while retaining high target inhibition. As a proof of concept, we investigated knockdown of the firefly luciferase reporter gene by combinatorial use of RNAi and U1i, and evaluated their inhibitory potential both in vitro and in vivo. Co-transfection of RNAi and U1i constructs showed additive reduction of luciferase expression up to 95% in vitro. We attained similar knockdown when RNAi and U1i constructs were hydrodynamically transfected into murine liver, demonstrating for the first time successful in vivo application of U1i. Moreover, we demonstrated long-term gene silencing by AAV-mediated transduction of murine muscle with RNAi/U1i constructs targeting firefly luciferase. In conclusion, these results provide a proof of principle for the combinatorial use of RNAi and U1i to enhance target gene knockdown in vivo.

Ovary development and maturation in Nezara viridula (L.) (Hemiptera: Pentatomidae)

Ovary development and maturation of Nezara viridula (L.) were evaluated by examining ovariole morphology and the alterations in the biochemical (protein synthesis related to reproduction) composition of the hemolymph. Quantitative and qualitative protein analyses were performed and ovary structural alterations for the pre-reproductive and reproductive stages were recorded. Total concentration of proteins in female hemolymph gradually increased until the end of the pre-mating stage, remaining unaltered thereafter. Proteins linked to reproduction (vitellogenins) appeared in the hemolymph 10 days after adult emergence and indicated the end of the pre-mating stage. After mating, total protein concentration in the hemolymph was lower compared to virgin females; vitellogenin levels were similar during most of the observation period. Oocyte development and maturation were gradual and age dependent. Ten-day-old females had chorionated oocytes ready for fertilization. Mating did not stimulate oocyte development in N. viridula, but the lack of mating activity appeared to have stimulated oocyte resorption in 17-day-old females.

Combination of RNA interference and U1 inhibition leads to increased inhibition of gene expression

RNA interference (RNAi) has been revolutionary for the specific inhibition of gene expression. However, the application of RNAi has been hampered by the fact that many siRNAs induce dose-dependent unwanted secondary effects. Therefore, new methods to increase inhibition of gene expression with low doses of inhibitors are required. We have tested the combination of RNAi and U1i (U1 small nuclear RNA—snRNA—interference). U1i is based on U1 inhibitors (U1in), U1 snRNA molecules modified to target a pre-mRNA and inhibit its gene expression by blocking nuclear polyadenylation. The combination of RNAi and U1i resulted in stronger inhibition of reporter or endogenous genes than that obtained using either of the techniques alone. The increased inhibition observed is stable over time and allows higher inhibition than the best obtained with either of the inhibitors alone even with decreased doses of the inhibitors. We believe that the combination of RNAi and U1i will be of interest when higher inhibition is required or when potent inhibitors are not available. Also, the combination of these techniques would allow functional inhibition with a decreased dose of inhibitors, avoiding toxicity due to dose-dependent unwanted effects.

Platynota rostrana (Walker) (Tortricidae) and Phidotricha erigens Raganot (Pyralidae): artificial diet effects on biological cycle

The lepidopterans Platynota rostrana (Walker) (Tortricidae) and Phidotricha erigens Raganot (Pyralidae) have been found frequently in citrus groves in São Paulo State in recent years. Since in Brazil, the fertility cycle of these two species is largely unknown, as are details of the damage wrought by them in crops, this research studied these aspects of the two species, which were kept under laboratory conditions (temperature 25 ± 2 °C, 70 ± 10% RH, 14 h photophase) and on an artificial diet. The duration of the biological cycle (egg-adult) for P. rostrana was 38.3 days and total viability was 44.0%; for P. erigens these values were 32.5 days and 63.6%, respectively. Both species showed five larval instars. Females of P. rostrana laid an average of 308 eggs, whereas those of P. erigens laid an average of 106 eggs. In both species, female pupae were heavier than males. Male and female longevity for both species was nearly 10 days. Based on the data obtained, the artificial diet produced better results in P. rostrana than in P. erigens. If these species, which have the potential to reach pest status in the citrus groves of São Paulo State, could be reared on an artificial diet, research on their control by alternative methods would be easier.

Liver transduction with a simian virus 40 vector encoding insulin-like growth factor I reduces hepatic damage and the development of liver cirrhosis

Liver transplantation is the only treatment for advanced liver cirrhosis. Therapies halting the progression of the disease are urgently needed. Administration of recombinant insulin-like growth factor-I (rIGF-I) induces hepatoprotective effects in experimental cirrhosis. Therefore, we analyzed the efficacy of a recombinant simian virus 40 vector (rSV40) encoding IGF-I (rSVIGF-I) to prevent cirrhosis progression. First, transgene expression was evaluated in mice injected with rSV40 encoding luciferase, which showed long-term hepatic expression of the transgene. Interestingly, luciferase expression increased significantly in CCl(4)-damaged livers and upon IGF-I administration, thus liver injury and IGF-I expression from rSVIGF-I should favor transgene expression. rSVIGF-I therapeutic efficacy was studied in rats where liver cirrhosis was induced by CCl(4) inhalation during 36 weeks. At the end of the study, the hepatic levels of IGF-I and IGF-binding protein 3 were higher in rSVIGF-I-treated rats than in control cirrhotic animals. Cirrhotic rats treated with rSVIGF-I had reduced serum bilirubin, transaminases and liver fibrosis scores and increased hepatic expression of hepatocyte growth factor and STAT3alpha as compared to cirrhotic animals. Furthermore, cirrhotic animals showed testis atrophy and altered spermatogenesis, whereas testicular size and histology were normal in cirrhotic rats that received rSVIGF-I. Therefore, rSV40-mediated sustained expression of IGF-I in the liver slowed cirrhosis progression.

The yeast nuclear cap binding complex can interact with translation factor eIF4G and mediate translation initiation

The mRNA cap structure is bound by either the nuclear (CBC) or the cytoplasmic (eIF4F) cap binding complex. Following mRNA export, CBC must be exchanged for eIF4F in the cytoplasm. It is not known how this exchange occurs or how this RNP remodeling event is integrated with mRNA function. Here we report genetic and biochemical evidence that the yeast translation initiation factor eIF4G associates with CBC, and that eIF4E, the eIF4F component that binds both the cap and eIF4G, antagonizes this interaction. Furthermore, we find that CBC can stimulate translation in extracts containing an eIF4G protein deficient for eIF4E binding. These data suggest that eIF4E binding to the eIF4G-CBC complex on newly exported mRNA displaces CBC, and that the first round of translation on mRNA may occur via a different mechanism than subsequent rounds.

Genetic and physical interactions involving the yeast nuclear cap-binding complex

Yeast strains lacking the yeast nuclear cap-binding complex (yCBC) are viable, although impaired in growth. We have taken advantage of this observation to carry out a genetic screen for components that show synthetic lethality (SL) with a cbp20-Delta cbp80-Delta double mutation. One set of SL interactions was due to mutations that were complemented by components of U1 small nuclear RNP (snRNP) and the yeast splicing commitment complex. These interactions confirm the role of yCBC in commitment complex formation. Physical interaction of yCBC with the commitment complex components Mud10p and Mud2p, which may directly mediate yCBC function, was demonstrated. Unexpectedly, we identified multiple SL mutations that were complemented by Cbf5p and Nop58p. These are components of the two major classes of yeast small nucleolar RNPs, which function in the maturation of rRNA precursors. Mutants lacking yCBC were found to be defective in rRNA processing. Analysis of the yCBC deletion phenotype suggests that this is likely to be due to a defect in the splicing of a subset of ribosomal protein mRNA precursors.

Luc7p, a novel yeast U1 snRNP protein with a role in 5' splice site recognition

The characterization of a novel yeast-splicing factor, Luc7p, is presented. The LUC7 gene was identified by a mutation that causes lethality in a yeast strain lacking the nuclear cap-binding complex (CBC). Luc7p is similar in sequence to metazoan proteins that have arginine-serine and arginine-glutamic acid repeat sequences characteristic of a family of splicing factors. We show that Luc7p is a component of yeast U1 snRNP and is essential for vegetative growth. The composition of yeast U1 snRNP is altered in luc7 mutant strains. Extracts of these strains are unable to support any of the defined steps of splicing unless recombinant Luc7p is added. Although the in vivo defect in splicing wild-type reporter introns in a luc7 mutant strain is comparatively mild, splicing of introns with nonconsensus 5' splice site or branchpoint sequences is more defective in the mutant strain than in wild-type strains. By use of reporters that have two competing 5' splice sites, a loss of efficient splicing to the cap proximal splice site is observed in luc7 cells, analogous to the defect seen in strains lacking CBC. CBC can be coprecipitated with U1 snRNP from wild-type, but not from luc7, yeast strains. These data suggest that the loss of Luc7p disrupts U1 snRNP-CBC interaction, and that this interaction contributes to normal 5' splice site recognition.

Interaction of influenza virus NS1 protein and the human homologue of Staufen in vivo and in vitro

A screening for human proteins capable of interacting with influenza virus NS1 has been carried out using the two-hybrid genetic trap in yeast. A cDNA corresponding to the human homologue of Drosophila melanogaster Staufen protein (hStaufen) was isolated that fulfilled all genetic controls of the two-hybrid protocol. Using a hStaufen cDNA isolated from a lambda human library, the interaction of hStaufen and NS1 proteins was characterised in vivo and in vitro. Co-transfection of NS1 cDNA and a partial cDNA of hStaufen led to the relocalisation of recombinant hStaufen protein from its normal accumulation site in the cytoplasm to the nuclear location of NS1 protein. NS1 and hStaufen proteins could be co-immunoprecipitated from extracts of co-transfected cells and from mixtures of extracts containing either protein, as well as from extracts of influenza virus-infected cells. Furthermore, both proteins co-localised in the ribosomal and polysomal fractions of influenza virus-infected cells. The interaction was also detected in pull-down experiments using a resin containing purified hStaufen and NS1 protein translated in vitro. Deletion mapping of the NS1 gene indicated that a mutant protein containing the N-terminal 81 amino acids is unable to interact with hStaufen, in spite of retaining full RNA-binding capacity. These results are discussed in relation to the possible mechanisms of action of hStaufen and its relevance for influenza virus infection.

A human sequence homologue of Staufen is an RNA-binding protein that is associated with polysomes and localizes to the rough endoplasmic reticulum

In the course of a two-hybrid screen with the NS1 protein of influenza virus, a human clone capable of coding for a protein with high homology to the Staufen protein from Drosophila melanogaster (dmStaufen) was identified. With these sequences used as a probe, cDNAs were isolated from a lambda cDNA library. The encoded protein (hStaufen-like) contained four double-stranded RNA (dsRNA)-binding domains with 55% similarity and 38% identity to those of dmStaufen, including identity at all residues involved in RNA binding. A recombinant protein containing all dsRNA-binding domains was expressed in Escherichia coli as a His-tagged polypeptide. It showed dsRNA binding activity in vitro, with an apparent Kd of 10(-9) M. Using a specific antibody, we detected in human cells a major form of the hStaufen-like protein with an apparent molecular mass of 60 to 65 kDa. The intracellular localization of hStaufen-like protein was investigated by immunofluorescence using a series of markers for the cell compartments. Colocalization was observed with the rough endoplasmic reticulum but not with endosomes, cytoskeleton, or Golgi apparatus. Furthermore, sedimentation analyses indicated that hStaufen-like protein associates with polysomes. These results are discussed in relation to the possible functions of the protein.

The nuclear cap-binding complex is a novel target of growth factor receptor-coupled signal transduction

In an attempt to further understand how nuclear events (such as gene expression, nuclear import/export, and cell cycle checkpoint control) might be subject to regulation by extracellular stimuli, we sought to identify nuclear activities under growth factor control. Using a sensitive photoaffinity labeling assay that measured [alpha-32P]GTP incorporation into nuclear proteins, we identified the 20-kDa subunit of the nuclear cap-binding complex (CBC) as a protein whose binding activity is greatly enhanced by the extracellular stimulation of serum-arrested cells. The CBC represents a 20- and 80-kDa heterodimer (the subunits independently referred to as CBP20 and CBP80, respectively) that binds the 7-methylguanosine cap on RNAs transcribed by RNA polymerase II. This binding facilitates precursor messenger RNA splicing and export. We have demonstrated that the [alpha-32P]GTP incorporation into CBP20 was correlated with an increased ability of the CBC to bind capped RNA and have used the [alpha-32P]GTP photoaffinity assay to characterize the activation of the CBC in response to growth factors. We show that the CBC is activated by heregulin in HeLa cells and by nerve growth factor in PC12 cells as well as during the G1/S phase of the cell cycle and when cells are stressed with UV irradiation. Additionally, we show that cap-dependent splicing of precursor mRNA, a functional outcome of CBC activation, can be catalyzed by growth factor addition to serum-arrested cells. Taken together, these data identify the CBC as a nuclear target for growth factor-coupled signal transduction and suggest novel mechanisms by which growth factors can influence gene expression and cell growth.

The mammalian staufen protein localizes to the somatodendritic domain of cultured hippocampal neurons: implications for its involvement in mRNA transport

In hippocampal neurons, certain mRNAs have been found in dendrites (), and their localization and translation have been implicated in synaptic plasticity (). One attractive candidate to achieve transport of mRNAs into dendrites is Staufen (Stau), a double-stranded RNA-binding protein, which plays a pivotal role in mRNA transport, localization, and translation in Drosophila (). Using antibodies raised against a peptide located in the RNA-binding domain IIa and a polyclonal antibody raised against a recently cloned human Staufen homolog, we identify a 65 kDa rat homolog in cultured rat hippocampal neurons. In agreement with the exclusive somatodendritic localization of mRNAs in these cells, we find that Staufen is restricted to the same domain. By immunoelectron microscopy, we show enrichment of the mammalian homolog of Stau (mStau) in the vicinity of smooth endoplasmic reticulum and microtubules near synaptic contacts. Finally, the association of the mStau with neuronal mRNAs is suggested by the colocalization with ribonucleoprotein particles specifically in distal dendrites known to contain mRNA, ribosomes, and translation factors (). These results suggest a role for mStau in the polarized transport and localization of mRNAs in mammalian neurons.

Participation of the nuclear cap binding complex in pre-mRNA 3' processing

Communication between the 5' and 3' ends is a common feature of several aspects of eukaryotic mRNA metabolism. In the nucleus, the pre-mRNA 5' end is bound by the nuclear cap binding complex (CBC). This RNA-protein complex plays an active role in both splicing and RNA export. We provide evidence for participation of CBC in the processing of the 3' end of the message. Depletion of CBC from HeLa cell nuclear extract strongly reduced the endonucleolytic cleavage step of the cleavage and polyadenylation process. Cleavage was restored by addition of recombinant CBC. CBC depletion was found to reduce the stability of poly(A) site cleavage complexes formed in nuclear extract. We also provide evidence that the communication between the 5' and 3' ends of the pre-mRNA during processing is mediated by the physical association of the CBC/cap complex with 3' processing factors bound at the poly(A) site. These observations, along with previous data on the function of CBC in splicing, illustrate the key role played by CBC in pre-mRNA recognition and processing. The data provides further support for the hypothesis that pre-mRNAs and mRNAs may exist and be functional in the form of "closed-loops," due to interactions between factors bound at their 5' and 3' ends.

Cleavage of p220 by purified poliovirus 2A(pro) in cell-free systems: effects on translation of capped and uncapped mRNAs

Poliovirus protease 2A(pro) has been obtained in soluble form as a fusion protein with maltose binding protein (MBP). Addition of MBP-2A(pro) to rabbit reticulocyte cell-free systems gives rise to efficient cleavage of the initiation factor of translation p220 (eIF-4G). Translation of capped mRNA encoding the influenza virus NP protein is severely impaired in lysates in which p220 has been proteolytically cleaved. This inhibition is dependent on the concentration of mRNA added to the lysate. Thus, increasing the concentrations of mRNA substantially overcomes the blockade of NP synthesis after p220 cleavage. Notably, translation of uncapped NP mRNA is also compromised in p220-deficient rabbit reticulocyte lysates, suggesting that p220 participates in the translation of both capped and uncapped NP mRNAs. The effects of p220 proteolysis by poliovirus 2A(pro) have also been assayed on luciferase mRNA translation. Three types of mRNAs encoding for luciferase have been examined: capped, uncapped, and mRNA bearing the poliovirus 5' leader region (leader luc mRNA). Synthesis of luciferase directed by any of these mRNAs was inhibited after cleavage of p220 in rabbit reticulocyte lysates. Interestingly, supplementation of the lysate with HeLa cell extracts stimulates leader luc mRNA translation by poliovirus 2A(pro). These results indicate that activation of translation of mRNAs bearing the poliovirus leader region promoted by this poliovirus protease requires a factor present in HeLa cell extracts. These findings agree well with recent experiments implicating p220 not only in protein synthesis directed by capped mRNAs but also in the translation of naturally uncapped mRNAs.

Influenza virus NS1 protein enhances the rate of translation initiation of viral mRNAs

The effect of NS1 protein on the efficiency of influenza virus mRNA translation was evaluated by determining the accumulation of nucleoprotein (NP) or M1 mRNAs in the cytoplasm of cells expressing either of these genes alone or in combination with the NS1 gene, as well as the total cell accumulation of NP or M1 protein. Coexpression of NS1, but not of NS2 protein, led to increases in the translation of these mRNAs in the range of 5- to 100-fold. This translation enhancement was specific for viral mRNAs, since the translation of neither cat nor lacZ mRNAs was affected by the coexpression of NS1 protein. The use of chimeric cat genes containing the 5'-extracistronic sequences of the influenza virus mRNAs corresponding to segment 2, 7, or 8 indicated that these sequences can in part account for the observed effect. The enhancement of viral mRNA translation mediated by NS1 protein was due to an increase in the translation initiation rate, since the sizes of NP-specific polysomes, but not those of lacZ-specific polysomes, was significantly higher in cells coexpressing NS1 protein than in those expressing only the NP gene.

Influenza virus NS1 protein alters the subnuclear localization of cellular splicing components

Intranuclear structure was studied in influenza virus-infected cells by immunofluorescence microscopy with antibodies specific for fibrillarin, the splicing factor SC35 and the autoantigen p80 coilin. In the course of the infection, an increase in the number of coiled bodies was observed, with a parallel decrease in their size. In addition, the normal speckled pattern of the SC35 factor was altered to generate a more punctate distribution. However, no alteration was observed in the fibrillarin staining pattern. Since an alteration in the splicing of both viral and cellular mRNAs upon expression of influenza virus NS1 protein has been reported previously, the possible effects of NS1 expression on intranuclear structure were assayed. The increase in the coiled body numbers was not specific for the expression of NS1 protein, but alterations in the nuclear location of small ribonucleoprotein particles, as determined by immunofluorescence with an anti-Sm serum or the SC35 splicing factor, were produced by the sole expression of NS1 protein. These results correlate with the previously reported inhibition of splicing induced by NS1 protein expression and suggest an interaction of this influenza virus protein with the cellular splicing machinery.

Influenza virus NS1 protein inhibits pre-mRNA splicing and blocks mRNA nucleocytoplasmic transport

The influenza virus RNA segment 8 encodes two proteins, NS1 and NS2, by differential splicing. The collinear transcript acts as mRNA for NS1 protein, while the spliced mRNA encodes NS2 protein. The splicing of NS1 mRNA was studied in cells transfected with a recombinant plasmid that has the cDNA of RNA segment 8 cloned under the SV40 late promoter and polyadenylation signals. As described for influenza virus-infected cells, NS1 mRNA was poorly spliced to yield NS2 mRNA. However, inactivation of the NS1 gene, but not the NS2 gene, led to a substantial increase in the splicing efficiency, as shown by the relative accumulations of NS1 and NS2 mRNAs. This effect was not specific for NS1 mRNA, since the splicing of the endogenous SV40 early transcript was altered in such a way that t-Ag mRNA was almost eliminated. These changes in the splicing pattern coincided with a strong inhibition of the mRNA nucleocytoplasmic transport. Both NS1 and NS2 mRNAs were retained in the nucleus of cells expressing NS1 protein, but no effect was observed when only NS2 protein was expressed. Furthermore, other mRNAs tested, such as T-Ag mRNA and the non-spliceable nucleoprotein transcript, were also retained in the nucleus upon expression of NS1 protein, suggesting that it induced a generalized block of mRNA export from the nucleus.

Splicing of influenza virus matrix protein mRNA expressed from a simian virus 40 recombinant

Influenza virus RNA segment 7 encodes two proteins, M1 and M2, depending on the optional removal of an intron from its primary transcript. To investigate the mechanism of this regulated splicing, an influenza virus segment 7 cDNA was cloned under the control of simian 40 virus (SV40) early promoter and poly(A) signals in an SV40 recombinant virus (SVM), and expressed in COS-1 cells. Expression of both M1 and M2 proteins was detected in SVM-infected cells, suggesting (i) the appropriate splicing events to generate M2 mRNA occur in these cells and (ii) significant amounts of unspliced M1 mRNA are transported to the cytoplasm. Analysis of the relative proportion of M2 mRNA to mRNA3 indicated that the use of the alternative 5' splice sites is reversed in SVM-infected cells compared with those infected with influenza virus. In addition, a different intranuclear distribution of segment 7 transcripts was found in each type of infected cell. We speculate that these differences in splicing efficiency and splice site choice might be related to different subnuclear localizations of segment 7 transcripts synthesized by the different transcriptional machineries.

Evaluation of blood collected on filter paper for detection of antibodies to human immunodeficiency virus type 1

This study was undertaken to evaluate the sensitivity and specificity of a commercial enzyme immunoassay in detecting antibody to human immunodeficiency virus type 1 using whole-blood specimens collected onto filter paper. Results obtained with specimens collected onto filter paper were comparable with those obtained with the corresponding serum or plasma specimens.

Inconsistent leukocyte removal by IBM 2991 blood cell processor

Studies done in the 1970's have documented the efficiency of leukocyte removal by saline washing using the IBM 2991 Blood Cell Processor. In June 1982, an evaluation of 52 consecutive units washed using the IBM 2991 yielded results for leukocyte removal that varied considerably from the results determined by previous published studies. Evidence from our institution and others within the last year supports a recent alteration in the ability of the IBM 2991 to remove leukocytes. Since the machine has not changed considerably since previous successful studies, alterations in the product being washed need to be considered as a cause of the inconsistency in leukocyte removal by the IBM 2991. Until consistent leukocyte-removal can be achieved, individual blood banks should carefully scrutinize their washed units and be prepared for possible leukocyte-associated reactions.