Modeling complete removal of risk assessment questions in the USA predicts the risk of HIV exposure in blood recipients could increase despite the use of nucleic acid testing.

BACKGROUND AND OBJECTIVES: The safety of the blood supply in a number of countries is achieved by interventions that include behaviour-based time-limited or indefinite deferrals and screening of donated units for transfusion-transmitted infections. The relatively high sensitivity of nucleic acid testing (NAT) used in blood donor screening has raised the question of whether such time-based deferrals can be eliminated in favour of individual risk assessment. MATERIALS AND METHODS: Data on the annual number of incident human immunodeficiency virus (HIV) infections associated with various behaviours and on the performance characteristics of NAT applied to donor screening were used to model the number of potentially infected units that might escape detection in the worst-case scenario in which individual risk assessment was implemented, but was not effective as a screening tool, and donors did not otherwise self-select for lower risk. RESULTS: In the absence of effective individual risk-based screening or donor self-selection, the model predicts that in the United States, an additional 39 (95% CI 35-43) HIV-infected units would escape detection by nucleic acid testing, potentially capable of exposing approximately 68 (95% CI 61-75) individuals to the risk of HIV infection through the administration of prepared blood components. CONCLUSION: Despite some inherent uncertainty, the worst-case scenario of completely ineffective individual risk assessment, absence of donor self-selection and increased reliance on NAT for blood screening is estimated to be associated with an approximately fourfold increase in the risk of HIV exposure through transfusion in the United States.

Establishment of the first international repository for transfusion-relevant bacteria reference strains: ISBT working party transfusion-transmitted infectious diseases (WP-TTID), subgroup on bacteria.

BACKGROUND: Bacterial contamination of platelet concentrates (PCs) still remains a significant problem in transfusion with potential important clinical consequences, including death. The International Society of Blood Transfusion Working Party on Transfusion-Transmitted Infectious Diseases, Subgroup on Bacteria, organised an international study on Transfusion-Relevant Bacteria References to be used as a tool for development, validation and comparison of both bacterial screening and pathogen reduction methods. MATERIAL AND METHODS: Four Bacteria References (Staphylococcus epidermidis PEI-B-06, Streptococcus pyogenes PEI-B-20, Klebsiella pneumoniae PEI-B-08 and Escherichia coli PEI-B-19) were selected regarding their ability to proliferate to high counts in PCs and distributed anonymised to 14 laboratories in 10 countries for identification, enumeration and bacterial proliferation in PCs after low spiking (0·3 and 0·03 CFU/ml), to simulate contamination occurring during blood donation. RESULTS: Bacteria References were correctly identified in 98% of all 52 identifications. S. pyogenes and E. coli grew in PCs in 11 out of 12 laboratories, and K. pneumoniae and S. epidermidis replicated in all participating laboratories. The results of bacterial counts were very consistent between laboratories: the 95% confidence intervals were for S. epidermidis: 1·19-1·32 × 10(7) CFU/ml, S. pyogenes: 0·58-0·69 × 10(7) CFU/ml, K. pneumoniae: 18·71-20·26 × 10(7) CFU/ml and E. coli: 1·78-2·10 × 10(7) CFU/ml. CONCLUSION: The study was undertaken as a proof of principle with the aim to demonstrate (i) the quality, stability and suitability of the bacterial strains for low-titre spiking of blood components, (ii) the property of donor-independent proliferation in PCs, and (iii) their suitability for worldwide shipping of deep frozen, blinded pathogenic bacteria. These aims were successfully fulfilled. The WHO Expert Committee Biological Standardisation has approved the adoption of these four bacteria strains as the first Repository for Transfusion-Relevant Bacteria Reference Strains and, additionally, endorsed as a project the addition of six further bacteria strain preparations suitable for control of platelet contamination as the next step of enlargement of the repository.

Co-amplification of multiple regions of the HIV-1 genome by the polymerase chain reaction: potential use in multiple diagnosis.

We have used the polymerase chain reaction (PCR) to detect by co-amplification, multiple regions of the HIV-1 genome in infected cells. Genomic RNA and DNA from productively infected H9 cells were independently extracted and amplified in reactions with and without reverse transcriptase respectively using primer pairs to the gag, env, tat and nef regions of the viral genome in the same reaction mixture. PCR-products were analysed by liquid hybridization with end labelled oligonucleotide probes followed by gel-electrophoresis (oligomer hybridization). The primer pairs were capable of detecting as few as 10 copies of RNA and 10-20 copies of integrated proviral DNA. The ability to co-amplify multiple target regions in the same incubation mixture provides a method for detecting and confirming the presence of HIV-1 in samples for which limited nucleic acid is available. In addition, in reconstitution experiments, the same method was used to detect HIV-1 and HTLV-I simultaneously with comparable sensitivity (20-40 gene copies each). This offers the possibility of simultaneous diagnosis of multiple viral infections, such as those that occur in AIDS, on the same sample preparation.

Kinetics of early HIV-1 gene expression in infected H9 cells assessed by PCR.

The time course of viral gene expression in H9 cells acutely infected with HIV-1 was analysed by the polymerase chain reaction (PCR). Virus-specific sequences were first detected in genomic DNA of H9 cells 1-2 h after infection. RNA for the regulatory genes such as the tat and nef appeared 2-3 h post-infection and RNA for the gag and env at 3 h. The results demonstrate that viral DNA synthesis occurs rapidly after infection of target cells followed by synthesis of viral RNA. Cell-associated reverse transcriptase activity increased after 24 h, while culture supernatant enzyme activity increased later, between 1-5 days. The delay in virus release after rapid integration and transcriptional activity suggests the involvement of additional factors, perhaps both cellular and viral, that control the formation and budding of mature virions.

Interferon-gamma inhibits HIV-induced invasiveness of monocytes.

HIV-infected monocytes form highly invasive network on basement membrane matrix and secrete high levels of 92-kd metalloproteinase (MMP-9), an enzyme that degrades basement membrane proteins. In the present study, using matrigel as a model basement membrane system, we demonstrate that treatment of human immunodeficiency virus (HIV)-infected monocytes with interferon-gamma at 50 U/ml inhibited the ability of infected monocytes to form an invasive network on matrigel and their invasion through the matrigel matrix. These effects were associated with a significant reduction in the levels of MMP-9 produced by HIV-infected monocytes treated with interferon-gamma 1 day prior to infection with HIV as compared with that of untreated HIV-infected monocytes. Monocytes treated with interferon-gamma 1 day after HIV infection showed the presence of integrated HIV sequences; however, the levels of MMP-9 were substantially lower than those produced by monocytes inoculated with live HIV, heat-inactivated HIV, or even the control uninfected monocytes. Exposure of monocytes to heat-inactivated HIV did not result in increased invasiveness or high MMP-9 production, suggesting that regulation of metalloproteinase by monocytes was independent of CD4-gp120 interactions and required active virus infection. Furthermore, addition of interferon-gamma to monocytes on day 10 after infection inhibited MMP-9 production by more than threefold with no significant reduction of virus replication. These results indicate that the mechanism of interferon-gamma-induced down-regulation of MMP-9 levels and reduced monocyte invasiveness may be mediated by a mechanism independent of antiviral activity of IFN-gamma in monocytes. Down-regulation of MMP-9 in HIV-infected monocytes by interferon-gamma may play an important role in the control of HIV pathogenesis.

Clotting factor product administration and same-day occurrence of thrombotic events, as recorded in a large healthcare database during 2008-2013.

BACKGROUND: Thrombotic events (TEs) are serious adverse events that can occur following administration of clotting factors (CFs). OBJECTIVES: To evaluate occurrence of same-day TEs for different CF products and potential risk factors. METHODS: A retrospective cohort study of individuals exposed to CF products during 2008-2013 was conducted using a large commercial insurance database. CF products were identified by procedure codes, and TEs were ascertained via diagnosis codes. Crude same-day TE rates (per 1000 persons exposed) were estimated overall and by congenital factor deficiency (CFD) status, CF products, age and gender. Multivariable logistic regression analyses were used to control for confounding. Laboratory analysis was used to compare the procoagulant activities of FIX products. RESULTS: Of 3801 individuals exposed to CFs, 117 (30.8 per 1000) had same-day TEs recorded. The crude same-day TE rate was higher for CF users without CFD, 70.2 (102 of 1452), as compared with those with CFD, 6.4 (15 of 2349) (RR, 11.0; 95% CI, 6.4-18.9). For individuals without CFD, a significantly increased same-day TE risk was identified for factor IX complex (OR, 6.92; 95% CI, 3.11-15.40), factor VIIa (OR, 9.42; 95% CI, 4.99-17.78) and other products when compared with fibrin sealant. An increased risk of a TE was found with older age (≥ 45 years), history of TEs and underlying health conditions. The laboratory identified elevated procoagulant activity in Profilnine(®) and Benefix(®) . CONCLUSIONS: The study shows an increased same-day TE risk for CF users without CFD and suggests substantial off-label CF use. The study findings also show elevated same-day TE rates for different CF products and suggest the importance of product properties and patient factors.

Impaired antigen presentation to CD4+ T-cells by HIV-infected monocytes is related to down-modulation of CD4 expression on helper T-cells: possible involvement of HIV-induced cellular factors.

Defective antigen presentation by HIV-infected monocytes is related to severe immune dysfunction in patients with AIDS, although the mechanism by which this process occurs is not well defined. Here we report that reduced capacity by HIV-infected monocytes to stimulate or present antigen to CD4+ T-cells was mediated by cellular factors associated with the plasma membranes of HIV-infected monocytes. In contrast, soluble factors secreted by HIV-infected monocytes had little or no effect on T-cell stimulation. Reduced T-cell stimulation by HIV-infected monocytes was related to down-modulation of CD4 expression on helper T-cells and was not affected by the inclusion of anti-HIV-gpl20 Ab, indicating the involvement of soluble or cell-associated viral envelope protein to be less likely. Exposure of CD4+ T-cells, that had been in co-culture with HIV-infected monocytes, to uninfected monocytes partially restored impaired T-cell stimulation. Thus, for the first time we report that altered capacity of HIV-infected monocytes to stimulate and present antigen to CD4+ T-cells is related to down-modulation of CD4 expression on T-cells, and appears to occur via membrane-associated cellular factors on HIV-infected monocytes.

Poor sensitivity, specificity, and reproducibility of detection of HIV-1 DNA in serum by polymerase chain reaction. The Transfusion Safety Study Group.

A series of recent studies have reported detection by the polymerase chain reaction (PCR) of cell-free human immunodeficiency virus type 1 (HIV-1) DNA (as opposed to virion RNA) in serum from both seropositive and seronegative persons. To evaluate the sensitivity, specificity, and reproducibility of PCR detection of cell-free HIV-1 DNA, we distributed coded panels containing 98 serum specimens obtained from well-characterized, infected individuals and control blood donors to the two laboratories with reported experience with this technique. Positive results were reported with HIV-1 gag primers (SK38/39) for 48 of 188 separate PCR determinations on DNA extracts from 44 serum samples from seropositive patients (25.5% sensitivity). HIV-1 gag signal was also reported for 28 of 151 PCR determinations on 34 samples from noninfected blood donors (18.5% false-positive rate). PCR for HIV-1 env DNA performed in one laboratory was negative on all specimens from seropositive and seronegative patients. Results for cell-free HIV-1 gag and human genomic (beta-globin or HLA DQ-alpha) DNA were inconsistent on replicate and serial specimens evaluated within each laboratory and between laboratories. These results indicate that current techniques for detecting cell-free HIV-1 DNA in serum lack adequate sensitivity, specificity, and reproducibility for widespread clinical applications.

An anti-p24 monoclonal antibody shows cross-reactivity with multiple HIV-1 proteins.

We produced three murine monoclonal antibodies (mAbs) against the HIV-1 proteins. These three mAbs, namely CA-1, CA-2, CA-4, were IgG1 and all reacted with p24 on the HIV-1 Western blot. One of the mAbs, CA-4, also recognized p13, p21, p28, p29, p32, p39, p47, p55 on the Biotech/Du Pont HIV-1 Western blot strips and p21, p24, p28, p29, p39, p47, p55, p68, p80, p96; p110 on the Bio-Rad strips. CA-4 did not react with H-9 cell lysate nor with other retroviral antigens such as HTLV-1 or HIV-2 proteins. The binding of CA-4 to HIV-1 proteins was not blocked by deglycosylation. All three mAbs reacted with recombinant DNA derived capsid protein (p24) of HIV-1. These results suggest that many proteins in the HIV-1 Western blot contain antigenic epitope(s) similar to that of p24.

9-Nitrocamptothecin inhibits tumor recrosis factor-mediated activation of human immunodeficiency virus type 1 and enhances apoptosis in a latently infected T cell clone.

Transition from latency to active replication is a crucial stage for the process of human immunodeficiency virus type 1 (HIV-1) infection and life cycle. HIV-1 replication in latently infected cells can be strongly induced by the cytokine tumor necrosis factor alpha (TNF-alpha) and the proliferation-arresting chemical sodium butyrate (NaB). We have investigated the ability of the drug 9-nitrocamptothecin (9NC), a potent cellular topoisomerase I (topo I) inhibitor currently in clinical trials in cancer patients, to regulate HIV-1 replication in latently infected lymphocytic ACH-2 cells on reactivation with either TNF-alpha or NaB. Treatment of ACH-2 cells with 9NC alone resulted in increased levels of viral transcripts, while there was a slight reduction or no change in the levels of host cell transcripts. However, pretreatment of ACH-2 cells with 9NC inhibited TNF-alpha-induced extracellular HIV-1 p24 levels up to approximately 95% and nearly 80% of the cell-associated viral RNAs. The quantitative decrease in viral products was concomitant with a decrease in cellular gene expression and induction of apoptosis in the host cells. 9NC blocked the infected cells at the boundary of the S and G2 phases, resulting in an accelerated apoptosis that was further enhanced with TNF-alpha treatment. Similar results were observed following concurrent exposure to TNF-alpha and 9NC, but 9NC failed to inhibit upregulation of HIV-1 mRNA in ACH-2 cells exposed to TNF-alpha before 9NC treatment. Further, 9NC had no inhibitory effect on NaB-induced apoptosis and upregulation of HIV-1 mRNA expression regardless of whether 9NC and NaB were used concurrently or in various treatment sequences. In uninfected lymphocytic CEM cells derived from a common parental cell line, a slight downregulation of cellular gene expression was detected along with low-level apoptosis. These results demonstrate that 9NC impairs TNF-alpha-induced, but not NaB-induced, HIV-1 activation, and suggest a means of inhibiting active HIV-1 viremia arising as a result of elevated TNF-alpha levels.

Evidence of HIV-2 infection in Equatorial Guinea (central Africa): partial genetic analysis of a B subtype virus.

PIP: A case of HIV-2 infection is described in a 35-year-old woman born in Malabo, Equatorial Guinea, who migrated to Madrid, Spain, in 1995. It was determined through questioning the woman that her only HIV-associated risk factor was unprotected heterosexual contacts in her country of origin. Her ex-husband, to whom she had been married for 18 years, was also from Equatorial Guinea and was known to have had multiple sex partners. The woman reported having had heterosexual encounters with five other partners in her native country, although less frequently than with her ex-husband. She was unaware of her sex partners' HIV serostatus and denied having had any sexual relations in Spain during her one-year current residency. The woman was in good health and presented with a CD4+ T cell count of 486 cubic millimeters. HIV-2 infection was identified using the Pepti-LAV immunoassay and Western blot. Isolation of the infecting virus was attempted by coculturing the patient's peripheral blood mononuclear cells (PBMCs) with PBMCs from an HIV-seronegative donor according to standard protocols for HIV isolation. Nested polymerase chain reaction was later conducted on some DNA from the woman's uncultured PBMCs. Phylogenetic analysis showed that the sequence data obtained clustered with the B subtype of HIV-2.^ieng

Inhibition of HIV-1 replication in H9 cells by nystatin-A compared with other antiviral agents.

Nystatin A was compared in vitro with amphotericin B, AZT, or foscarnet for their respective abilities to inhibit the replication of human immunodeficiency virus type 1 (HIV-1) in H9 cells. HIV-1-infected H9 cells were cultured for 7 days in the presence of each of these drugs, at various concentrations. Reverse transcriptase activity and p24 antigen production were quantitated. Untreated, HIV-1-infected H9 cells served as the control. Nystatin A inhibited viral replication most effectively at 10 micrograms/ml, a concentration that did not affect cell viability. Nystatin-A treatment inhibited RT activity by 85% and p24 production by 90%. These levels of inhibition were comparable to that mediated by amphotericin B, AZT, or foscarnet at 10, 25, and 50 micrograms/ml, respectively. Western blot analysis of the HIV-1-infected H9 cells treated with these drugs did not detect any expression of viral proteins. These findings were further corroborated by indirect immunofluorescence studies using monoclonal anti-gp120 FITC-conjugated antibodies and by polymerase chain reaction for proviral DNA analysis, using a 32P-labeled probe. These results suggest that Nystatin A merits attention as an antiviral drug for the treatment of HIV-1 infection. In vivo drug delivery by liposome encapsulation to overcome problems of bioavailability is currently under study.

Inhibition of HIV replication by immunoliposomal antisense oligonucleotide.

The sequence-specific suppression of HIV-1 replication using CD4 monoclonal-antibody-targeted liposomes, containing Rev antisense phosphorothioate oligonucleotides is described. Liposomes were prepared by encapsulating the 20-mer antisense DNA sequence of the rev HIV-1 regulatory gene, in the form of a phosphorothioate oligonucleotide. Specific targeting was accomplished by conjugating anti-CD4 mouse monoclonal antibody to the surface of the liposomes. HIV-1-infected H9 cells as well as peripheral blood T-lymphocytes were incubated with the immunoliposomes of antisense found to have potential antiviral effect. HIV-1 replication was reduced by 85% in antisense immunoliposome-treated H9 cells and peripheral blood lymphocytes, whereas the inhibition of HIV-1 replication was not observed using either empty immunoliposomes or immunoliposomes containing scrambled Rev phosphorothioate oligonucleotide sequences. The antiviral activity of both the free and the encapsulated oligonucleotides were assessed by p24, reverse transcriptase (RT) assays and polymerase chain reaction (PCR) analysis. Liposome preparations demonstrated minimal toxicity in H9 as well as in peripheral blood lymphocyte cell culture experiments. These in vitro culture results demonstrate the potential efficacy of immunoliposomes to inhibit HIV replication.

Enhanced diagnostic efficiency of the polymerase chain reaction by co-amplification of multiple regions of HIV-1 and HIV-2.

A method for co-amplification of multiple viral sequences of HIV-1 and HIV-2 by polymerase chain reaction was designed. The technique resulted in the specific detection of each type of virus and allowed the amplification of as few as two copies of target DNA. The amplification of multiple regions of the viral genome offers the advantage of detecting multiple target sequences, which may be essential for some viruses, such as HIV, that exhibit a high degree of variability in their gene sequences. In addition, the method permitted the detection of both virus types in the same reaction, allowing for greater utility in geographic areas where coinfections with both viruses occur and cross-reactivity in Western blots is observed. This method was applied successfully to the detection of viral DNA in clinical specimens.

A novel, sensitive radioimmunoprecipitation assay for the detection of antibodies to human immunodeficiency virus-type 2.

A radioimmunoprecipitation assay that provides an alternative to the Western blot assay was developed for characterizing antibodies against human immunodeficiency virus type-2 (HIV-2). The assay is based on radioiodination of antigen using Bolton-Hunter reagent. The antigen consists of a soluble preparation of the NIH-Z (HIV-2) strain of 1000X purified virus spiked with purified recombinant HIV-2 gp105. Radiolabeled proteins were immunoprecipitated by immune human sera, even at the early stages of seroconversion. This new assay provides a simple method for characterizing and titrating antibodies against HIV-2. The method is more sensitive, and is more efficient than Western blotting. The labeled viral proteins are well suited for biochemical studies.

The effects of the AIDS epidemic on the safety of the nation's blood supply.

Present safeguards for the blood supply consist of three tiers of protection: donor deferral based on a donor's history of risk factors, confidential exclusion of blood units from donors with self-admitted risk factors, and testing of the blood itself. Before the discovery of the AIDS virus in 1983 and 1984, there was no specific test relevant to AIDS that could be used to help improve the safety of the blood supply. The first step was intensified efforts, based on what was then known of the epidemiology of the disease, to take donor histories to identify risk factors. The first specific tests were for the detection of antibodies to the virus and came into use in 1985. The general features of AIDS are described, together with the scientific rationale for the various types of laboratory tests, those for the virus itself, antigens, antibodies, the genetic material of the virus, and T4 lymphocytes. General characteristics of the tests are reviewed. Since testing began, about 30 million units each of blood and plasma have been screened. More than 3,000 infected persons in the blood donor group have been identified as HIV-antibody positive. Thirteen cases of transfusion-associated infection have been documented. They are believed to have occurred because a detectable level of antibodies had not yet formed in the infected donors. Currently, such transmission is thought to occur once in about 40,000 to 250,000 donations, a dramatic improvement from 1983.

Current safety of clotting factor concentrates.

Earlier commercial clotting factor concentrates transmitted hepatitis viruses to 100% and acquired immunodeficiency syndrome viruses to 60% to 80% of patients with hemophilia. Transmission of the human immunodeficiency virus was nearly eliminated by heating concentrates in the lyophilized state, which has been done since 1983. However, human immunodeficiency virus infections were still transmitted by some products "dry heated" under conditions less extreme than 68 degrees C for 72 hours. Newer virus-inactivating procedures include "dry heating" at 80 degrees C for 72 hours, modified heating in n-heptane or water vapor, heating in solution, treatment with solvent-detergent mixtures, monoclonal affinity purification plus inactivation, and alkylation with beta-propiolactone (only for factor IX complex). These procedures have eliminated significant loads of human immunodeficiency virus, hepatitis B virus, and non-A, non-B hepatitis virus in laboratory studies. However, clinical studies have shown transmission of hepatitis non-A, non-B for products "dry heated" except at 80 degrees C and for products heated in n-heptane. Elimination of hepatitis B has been difficult to demonstrate, suggesting a continued need for immunization.

Prevention of early otorrhea in ventilation tubes.

The incidence of early postoperative otorrhea after placement of ventilation tubes ranges from 12% to 40%. This prospective randomized study of 430 children, ages 6 months to 15 years, examined the efficacy of sulfacetamide/prednisolone otic drops used for 3 days postoperatively in reducing the incidence of otorrhea at 1 week after the placement of Donaldson tubes. Subjects were randomized into two groups--drops and no drops. Preoperative diagnosis and intraoperative findings were correlated with findings. The incidence of otorrhea among all patients was 11.9%. The use of sulfacetamide/prednisolone drops for 3 days after insertion of ventilation tubes failed to reduce the incidence of otorrhea in the overall study population. The drops did demonstrate a trend toward reducing the incidence of otorrhea in certain subpopulations, including children under 3 years of age, blood at the myringotomy site, and thick middle ear effusions. Subpopulations associated with a higher incidence of otorrhea were also identified.

Revision surgical hair restoration: repair of undesirable results.

Surgical hair restoration has been performed as a treatment for male pattern hair loss for more than 40 years. Although techniques have changed dramatically over the past several years, making it possible to achieve natural-appearing results, there are still many patients with unacceptable outcomes. These patients may have had procedures performed in the past with antiquated techniques or performed recently with substandard techniques. The causes of unfavorable results can be classified into one of three categories: technical errors, poor planning, or complications. The results in these patients can be dramatically improved through a number of different reparative surgical techniques. The majority of these techniques can be performed in an office outpatient setting. More than 40 patients unsatisfied with previous surgical hair restoration have been treated with the different techniques reviewed in this article. All patients had successful outcomes with significant improvement in appearance. Despite the increased challenges when performing reparative surgery, outcomes were favorable in all patients, with small to significant improvements in appearance achieved. Some of these challenges include the limited supply of donor hairs, reduced scalp laxity, and theoretically reduced vascularity due to scarring and transected blood vessels, and patient skepticism. Furthermore, the few complications that occurred were minor and correctable, including one case each of poor hair growth associated with extensive small graft (consisting of one to four hairs) transplanting, and of scalp scarring associated with the removal and primary closure of a large number of "plug" grafts (typically grafts 3 to 4 mm in size consisting of seven or more hairs) in a single procedure.

Indium 111-labeled leukocyte scintigraphy in evaluating head and neck infections.

This retrospective study looked at the role of indium 111-labeled white blood cell (111In WBC) scintigraphy in head and neck infections. The efficacy of 111In WBCs was compared to gallium 67 citrate (67Ga) and technetium Tc99m methylene diphosphonate (99mTc MDP) scintigraphy in detecting and monitoring the resolution of infection. For 22 active infections, the sensitivities for 111In WBC, 67Ga, and 99mTc MDP scintigraphy were 94%, 56%, and 86%, respectively, and the specificities for 111In WBC, 67Ga, and 99mTc MDP scintigraphy were 100%, 43%, and 0%, respectively. For 8 successfully treated infections, all seven 111In WBC studies became negative after therapy, in as short an interval as 1 month. In contrast, all seven 99mTc MDP images remained positive for as long as 6 months after therapy. The seven 67Ga studies had variable results, with four (57%) remaining positive, including two (28%) positive at 6 months after therapy. These results suggest that 111In WBC scintigraphy should be the initial radionuclide imaging tool in detecting active head and neck infections because of its greater accuracy, and its ability to revert to normal much sooner than 67Ga or 99mTc MDP scintigraphs when applied to a subset of patients with resolved infections.