Improving Pneumococcal Vaccination Rates in Immunosuppressed Pediatric Patients with Rheumatic Disease

Background

Patients with rheumatic diseases are at a high risk of invasive pneumococcal disease due to immunosuppression. We conducted a quality improvement project, and the first aim was to increase the percentage of patients with systemic lupus erythematosus and mixed connective tissue disease that is up to date on pneumococcal vaccinations from 9.6% to 80% within one year. Subsequently, the second aim was to increase the percentage of patients on immunosuppression with systemic lupus erythematosus, mixed connective tissue disease, juvenile dermatomyositis and systemic vasculitis that is up to date on pneumococcal vaccinations from 62.6% to 80% within one year.

Methods

Two process measures were up-to-date vaccination status on (1) 13-valent pneumococcal conjugated vaccine (PCV13) and (2) 23-valent pneumococcal polysaccharide vaccine (PPSV23). Our outcome measure was being fully up to date on both pneumococcal vaccinations. Interventions included an immunization algorithm, reporting of eligible patients, education, reminders, and pre-visit planning.

Results

There were shifts in the centerline for all quality measures in both phases of this project. The combined pneumococcal vaccination rate for Phase 1 increased from 9.6% to 91.1%, and this centerline was sustained. Pneumococcal vaccination rates also significantly increased for Phase 2: 68.8% to 93.4% for PCV13, 65.2% to 88.5% for PPSV23, and 62.6% to 86.5% for the combined pneumococcal vaccination rate.

Conclusions

Quality improvement methodology significantly increased and sustained pneumococcal vaccination rates in our high-risk, immunosuppressed patients. We continue to prioritize this important initiative to mitigate the risk of invasive pneumococcal disease.

Disease Course, Treatments, and Outcomes of Children With Systemic Juvenile Idiopathic Arthritis-Associated Lung Disease

OBJECTIVE

Systemic juvenile idiopathic arthritis-associated lung disease (SJIA-LD) is a life-threatening disease complication. Key questions remain regarding clinical course and optimal treatment approaches. The objectives of the study were to detail management strategies after SJIA-LD detection, characterize overall disease courses, and measure long-term outcomes.

METHODS

This was a prospective cohort study. Clinical data were abstracted from the electronic medical record, including current clinical status and changes since diagnosis. Serum biomarkers were determined and correlated with presence of LD.

RESULTS

We enrolled 41 patients with SJIA-LD, 85% with at least one episode of macrophage activation syndrome and 41% with adverse reactions to a biologic. Although 93% of patients were alive at last follow-up (median 2.9 years), 37% progressed to requiring chronic oxygen or other ventilator support, and 65% of patients had abnormal overnight oximetry studies, which changed over time. Eighty-four percent of patients carried the HLA-DRB1*15 haplotype, significantly more than patients without LD. Patients with SJIA-LD also showed markedly elevated serum interleukin-18 (IL-18), variable C-X-C motif chemokine ligand 9 (CXCL9), and significantly elevated matrix metalloproteinase 7. Treatment strategies showed variable use of anti-IL-1/6 biologics and addition of other immunomodulatory treatments and lung-directed therapies. We found a broad range of current clinical status independent of time from diagnosis or continued biologic treatment. Multidomain measures of change showed imaging features were the least likely to improve with time.

CONCLUSION

Patients with SJIA-LD had highly varied courses, with lower mortality than previously reported but frequent hypoxia and requirement for respiratory support. Treatment strategies were highly varied, highlighting an urgent need for focused clinical trials.

Measuring Disease Damage and Its Severity in Childhood-Onset Systemic Lupus Erythematosus

OBJECTIVE

To describe the frequency and types of disease damage occurring with childhood-onset systemic lupus erythematosus (SLE) as measured by the 41-item Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI), and to assess the SDI's ability to reflect damage severity.

METHODS

Information for the SDI was prospectively collected from 1,048 childhood-onset SLE patients. For a subset of 559 patients, physician-rated damage severity measured by visual analog scale (MD VAS damage) was also available. Frequency of SDI items and the association between SDI summary scores and MD VAS damage were estimated. Finally, an international consensus conference, using nominal group technique, considered the SDI's capture of childhood-onset SLE-associated damage and its severity.

RESULTS

After a mean disease duration of 3.8 years, 44.2% of patients (463 of 1,048) already had an SDI summary score >0 (maximum 14). The most common SDI items scored were proteinuria, scarring alopecia, and cognitive impairment. Although there was a moderately strong association between SDI summary scores and MD VAS damage (Spearman's r = 0.49, P < 0.0001) in patients with damage (SDI summary score >0), mixed-effects analysis showed that only 4 SDI items, each occurring in <2% of patients overall, were significantly associated with MD VAS damage. There was consensus among childhood-onset SLE experts that the SDI in its current form is inadequate for estimating the severity of childhood-onset SLE-associated damage.

CONCLUSION

Disease damage as measured by the SDI is common in childhood-onset SLE, even with relatively short disease durations. Given the shortcomings of the SDI, there is a need to develop new tools to estimate the impact of childhood-onset SLE-associated damage.

American College of Rheumatology Provisional Criteria for Clinically Relevant Improvement in Children and Adolescents With Childhood-Onset Systemic Lupus Erythematosus

OBJECTIVE

To develop a Childhood Lupus Improvement Index (CHILI) as a tool to measure response to therapy in childhood-onset systemic lupus erythematosus (cSLE), with a focus on clinically relevant improvement (CRI_{c SLE} ).

METHODS

Pediatric nephrology and rheumatology subspecialists (n = 213) experienced in cSLE management were invited to define CRI_{c SLE} and rate a total of 433 unique patient profiles for the presence/absence of CRI_{c SLE} . Patient profiles included the following cSLE core response variables (CRVs): global assessment of patient well-being (patient-global), physician assessment of cSLE activity (MD-global), disease activity index score (here, we used the Systemic Lupus Erythematosus Disease Activity Index), urine protein-to-creatinine ratio, and Child Health Questionnaire physical summary score. Percentage and absolute changes in these cSLE-CRVs (baseline versus follow-up) were considered in order to develop candidate algorithms and validate their performance (sensitivity, specificity, area under the receiver operating characteristic curve [AUC]; range 0-1).

RESULTS

During an international consensus conference, unanimous agreement on a definition of CRI_{c SLE} was achieved; cSLE experts (n = 13) concurred (100%) that the preferred CHILI algorithm considers absolute changes in the cSLE-CRVs. After transformation to a range of 0-100, a CHILI score of ≥54 had outstanding accuracy for identifying CRI_{c SLE} (AUC 0.93, sensitivity 81.1%, and specificity 84.2%). CHILI scores also reflect minor, moderate, and major improvement for values exceeding 15, 68, and 92, respectively (all AUC ≥0.92, sensitivity ≥93.1%, and specificity ≥73.4%).

CONCLUSION

The CHILI is a new, seemingly highly accurate index for measuring CRI in cSLE over time. This index is useful to categorize the degree of response to therapy in children and adolescents with cSLE.

Organ involvement other than lupus nephritis in childhood-onset systemic lupus erythematosus

In this review we critically analyze pulmonary, gastrointestinal and cardiac manifestations of childhood-onset systemic lupus erythematosus (cSLE). Clinical manifestations of these organ systems may be the initial manifestation of cSLE; frequently occur with very active cSLE; and are potential life-threatening manifestations often presenting to the emergency department and requiring admission to the intensive care unit. Early recognition and treatment of the pulmonary, gastrointestinal and cardiac manifestations of cSLE will result in improved prognosis and better outcomes.

Supercooling of Atoms in an Optical Resonator

We investigate laser cooling of an ensemble of atoms in an optical cavity. We demonstrate that when atomic dipoles are synchronized in the regime of steady-state superradiance, the motion of the atoms may be subject to a giant frictional force leading to potentially very low temperatures. The ultimate temperature limits are determined by a modified atomic linewidth, which can be orders of magnitude smaller than the cavity linewidth. The cooling rate is enhanced by the superradiant emission into the cavity mode allowing reasonable cooling rates even for dipolar transitions with ultranarrow linewidth.

Conditional ramsey spectroscopy with synchronized atoms

We investigate Ramsey spectroscopy performed on a synchronized ensemble of two-level atoms. The synchronization is induced by the collective coupling of the atoms to a heavily damped mode of an optical cavity. We show that, in principle, with this synchronized system it is possible to observe Ramsey fringes indefinitely, even in the presence of spontaneous emission and other sources of individual-atom dephasing. This could have important consequences for atomic clocks and a wide range of precision metrology applications.

Synchronization of two ensembles of atoms

We propose a system for observing the correlated phase dynamics of two mesoscopic ensembles of atoms through their collective coupling to an optical cavity. We find a dynamical quantum phase transition induced by pump noise and cavity output coupling. The spectral properties of the superradiant light emitted from the cavity show that at a critical pump rate the system undergoes a transition from the behavior of two independent oscillators to the phase locking that is the signature of quantum synchronization.

Frequency of thrombocytopenia in psoriasis patients treated with tumor necrosis factor-a inhibitors

Tumor necrosis factor-? (TNF-?) inhibitors are biologic agents that are currently in wide use for the treatment of psoriasis as well as other inflammatory diseases. Following reports of thrombocytopenia as a potential adverse effect of anti-TNF-? therapy, we performed a retrospective study to determine the frequency of thrombocytopenia, defined as a platelet count <50x109 cells/L, in a cohort of 187 psoriatic patients treated with anti-TNF-? agents over a nine-year period. Although none of our patients met serologic criteria for thrombocytopenia or displayed clinical manifestations of thrombocytopenia, two patients developed platelet counts below 100×109 cells/L. Thrombocytopenia induced by anti-TNF-? agents is a potential adverse effect, it is a rare occurrence that will require further investigation in large, placebo-controlled, double-blind, prospective studies.

Host genetic studies in human ocular Chlamydial infection

Several human and animal models and methods have been used to dissect genetic contributions to immunity and pathogenesis of chlamydial diseases. Considerable achievements have been made in this field of host genetics. The hope is that these studies will lead to medical applications by helping to elicit the function of genes that are involved in host defense against chlamydia and in progression to severe sequelae. In the present article, we review a selection of findings in the forward genetics of ocular Chlamydia trachomatis infection in humans.

Atomtronic circuits of diodes and transistors

We illustrate that open quantum systems composed of neutral, ultracold atoms in one-dimensional optical lattices can exhibit behavior analogous to semiconductor electronic circuits. A correspondence is demonstrated for bosonic atoms, and the experimental requirements to realize these devices are established. The analysis follows from a derivation of a quantum master equation for this general class of open quantum systems.

Prospects for a millihertz-linewidth laser

We propose a new light source based on having alkaline-earth atoms in an optical lattice collectively emit photons on an ultranarrow clock transition into the mode of a high Q resonator. The resultant optical radiation has an extremely narrow linewidth in the mHz range, even smaller than that of the clock transition itself due to collective effects. A power level of order 10;{-12} W is possible, sufficient for phase locking a slave optical local oscillator. Realizing this light source has the potential to improve the stability of the best clocks by 2 orders of magnitude.

Risk factors for active trachoma in The Gambia

Trachoma has been endemic in The Gambia for decades but national surveys indicate that the prevalence is falling. Risk factor data can help guide trachoma control efforts. This study investigated risk factors for active trachoma and ocular Chlamydia trachomatis infection in children aged below 10 years in two Gambian regions. The overall prevalence of C. trachomatis infection was only 0.3% (3/950) compared with 10.4% (311/2990) for active trachoma, therefore analyses were only performed for active trachoma. After adjustment, increased risk of trachoma was associated with being aged 1-2 years (odds ratio (OR) 2.20, 95% CI 1.07-4.52) and 3-5 years (OR 3.62, 95% CI 1.80-7.25) compared with <1 year, nasal discharge (OR 2.07, 95% CI 1.53-2.81), ocular discharge (OR 2.68, 95% CI 1.76-4.09) and there being at least one other child in the household with active trachoma (OR 11.28, 95% CI 8.31-15.31). Compared with other occupations, children of traders had reduced risk (OR 0.53, 95% CI 0.30-0.94). At the household level, only the presence of another child in the household with active trachoma was associated with increased risk of active trachoma, suggesting that current trachoma control interventions are effective at this level. In contrast, child-level factors were associated with increased risk after adjustment, indicating a need to increase control efforts at the child level.

FOXP3 gene expression in a tuberculosis case contact study

Regulatory T lymphocytes (T(regs)) that express FOXP3 are involved in the beneficial attenuation of immunopathology, but are also implicated in down-regulation of protective responses to infection. Their role in tuberculosis (TB) is unknown. We classified 1272 healthy TB contacts according to their tuberculin skin test (TST) and interferon (IFN)-gamma enzyme-linked immunospot (ELISPOT) results and 128 TB cases, and studied the expression of FOXP3 and interleukin (IL)-10 in blood samples. Compared to the uninfected contact group (TST(-), ELISPOT(-)), we observed higher levels of FOXP3 mRNA in blood from TB patients (< 0.001), but IL-10 expression was slightly lower (P = 0.04). In contrast, FOXP3 expression levels were significantly lower (P = 0.001) in the recently infected contacts (TST(+), ELISPOT(+)) but there was no difference for IL-10 (P = 0.74). We hypothesize that during early/subclinical TB, most of which will become latent, FOXP3(+) T(regs) may be sequestered in the lungs, but when TB becomes progressive, FOXP3 reappears at increased levels in the periphery. While these findings do not reveal the role, beneficial or harmful, of T(regs) in TB, they emphasize the probable importance of these cells.

Genetic variation at the TNF locus and the risk of severe sequelae of ocular Chlamydia trachomatis infection in Gambians

Tumor necrosis factor (TNF) is thought to be a key mediator of the inflammatory and fibrotic response to Chlamydia trachomatis (Ct) infection. A large matched-pair case-control study investigated putative functional single nucleotide polymorphisms (SNPs) across the major histocompatibility complex (MHC) class III region, including TNF and its immediate neighbors nuclear factor of kappa light polypeptide gene enhancer in B cells (IkappaBL), inhibitor like 1 and lymphotoxin alpha (LTA) in relation to the risk of scarring sequelae of ocular Ct infection. Haplotype and linkage disequilibrium analysis demonstrated two haplotypes, differing at position TNF-308, conferring an increased risk of trichiasis. The TNF-308A allele, and its bearing haplotype, correlated with increased TNF production in lymphocyte cultures stimulated with chlamydial elementary body antigen. Thus TNF-308A may determine directly, or be a marker of a high TNF producer phenotype associated with increased risk of sequelae of chlamydial infection. Multivariate analysis provided evidence for the presence of additional risk-associated variants near the TNF locus.

Bose-Einstein condensates in rotating lattices

Strongly interacting bosons in a two-dimensional rotating square lattice are investigated via a modified Bose-Hubbard Hamiltonian. Such a system corresponds to a rotating lattice potential imprinted on a trapped Bose-Einstein condensate. Second-order quantum phase transitions between states of different symmetries are observed at discrete rotation rates. For the square lattice we study, there are four possible ground-state symmetries.

Temporal cytokine gene expression patterns in subjects with trachoma identify distinct conjunctival responses associated with infection

Ocular chlamydial disease is clinically diagnosed by the appearance of characteristic inflammatory changes and development of lymphoid follicles in the conjunctiva. Nucleic acid amplification tests and relatively non-invasive methods of sampling the conjunctival surface can be used to quantify the expression of chlamydial and host genes. Using quantitative real-time polymerase chain reaction to detect the presence of Chlamydia trachomatis (CT) 16S rRNA and human interleukin (IL)-1beta, IL-10, IL-12p40, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha transcripts we examined the immune response at the conjunctival surface in a cohort of children living in a trachoma-endemic village in The Gambia. Elevated cytokine transcript levels were associated with the presence of CT 16S rRNA. Subclinical infection (CT infection without clinical signs of disease) elicited an immune response that is proinflammatory in nature, with elevations in the transcription of IL-1beta, IFN-gamma and IL-12p40. Clinically apparent infections were associated with the elevation of mRNA for the multi-functional cytokine TNF-alpha (fibrotic, type 1 inflammatory and regulatory) and the counter regulatory cytokine, IL-10, in addition to the other proinflammatory cytokines. A positive correlation between IFN-gamma transcript levels and the amount of CT 16S rRNA expressed in conjunctiva was found.

Risk of trachomatous scarring and trichiasis in Gambians varies with SNP haplotypes at the interferon-gamma and interleukin-10 loci

Experimental evidence implicates interferon gamma (IFNgamma) in protection from and resolution of chlamydial infection. Conversely, interleukin 10 (IL10) is associated with susceptibility and persistence of infection and pathology. We studied genetic variation within the IL10 and IFNgamma loci in relation to the risk of developing severe complications of human ocular Chlamydia trachomatis infection. A total of 651 Gambian subjects with scarring trachoma, of whom 307 also had potentially blinding trichiasis and pair-matched controls with normal eyelids, were screened for associations between single-nucleotide polymorphisms (SNPs), SNP haplotypes and the risk of disease. MassEXTEND (Sequenom) and MALDI-TOF mass spectrometry were used for detection and analysis of SNPs and the programs PHASE and SNPHAP used to infer haplotypes from population genetic data. Multivariate conditional logistic regression analysis identified IL10 and IFNgamma SNP haplotypes associated with increased risk of both trachomatous scarring and trichiasis. SNPs in putative IFNgamma and IL10 regulatory regions lay within the disease-associated haplotypes. The IFNgamma +874A allele, previously linked to lower IFNgamma production, lies in the IFNgamma risk haplotype and was more common among cases than controls, but not significantly so. The promoter IL10-1082G allele, previously associated with high IL10 expression, is in both susceptibility and resistance haplotypes.

An index of community ocular Chlamydia trachomatis load for control of trachoma

Quantitative PCR (Q-PCR) technology has recently been applied to the measurement of ocular loads of Chlamydia trachomatis. We present an index called the community ocular C. trachomatis load (COCTL) which is similar to the community microfilarial load (CMFL) of onchocerciasis. Our index has the advantage of being scale-independent so that, for example, percentage changes are the same whether calculated per eye swab or per Q-PCR capillary. The COCTL for a population or subgroup is formed by adding the arbitrary concentration of 1 organism per ml to each individual Q-PCR quantification, calculating the geometric mean, and finally subtracting 1 per ml again. The use of the COCTL is illustrated in a study of trachoma in northern Tanzania. The COCTL is higher in people with clinical trachoma than those without (5.8 organisms per swab vs. 0.1), and in children aged six months to ten years than in the overall population (1.1 vs. 0.4). The COCTL index is potentially useful for sentinel sites, operational research and calibration of clinical measures of trachoma.

Mutations in the nucleosome core enhance transcriptional silencing

Transcriptional silencing in Saccharomyces requires specific nucleosome modifications promoted in part by a complex of Sir proteins that binds to the modified nucleosomes. Recent evidence suggests that modifications of both the histone amino termini and the core domain of nucleosomes contribute to silencing. We previously identified histone H4 mutations affecting residues in the core of the nucleosome that yield enhanced silencing at telomeres. Here we show that enhanced silencing induced by these mutations increases the proportion of cells in which telomeres and silent mating-type loci are in the silent state. One H4 mutation affects the expression of a subset of genes whose expression is altered by deletion of HTZ1, which encodes the histone variant H2A.Z, suggesting that the mutation may antagonize H2A.Z incorporation into nucleosomes. A second mutation causes the spread of silencing into subtelomeric regions that are not normally silenced in wild-type cells. Mechanistically, this mutation does not significantly accelerate the formation of silent chromatin but, rather, reduces the rate of decay of the silenced state. We propose that these mutations use distinct mechanisms to affect the dynamic interplay between activation and repression at the boundary between active and silent chromatin.

Increased sample capacity for genotyping and expression profiling by kinetic polymerase chain reaction

We fabricated and evaluated high-throughput kinetic thermal cyclers with 768-reaction capacity for kinetic polymerase chain reaction (kPCR)-based genotyping and kinetic reverse transcription (kRT)-PCR-based transcript quantitation. The system uses dye-based detection with ethidium bromide and a single DNA polymerase-based PCR or RT-PCR assay. Allele-specific detection of the two most common hereditary hemochromotosis mutant alleles, C282Y and H63D, was reliably measured by kPCR using human DNA templates as low as 10 genome equivalents per assay. Transcript profiling was performed for 16 yeast transcripts ranging in intracellular abundance over four orders of magnitude. Standard deviations of the PCR cycle threshold values determined from multiple kRT-PCR assays in three different instruments ranged from 0.11 to 0.97 PCR cycles and were reproducible, transcript specific, and instrument independent. The effects of the sin3, gal11, and snf2 knockout mutations on expression of 385 yeast genes were evaluated by kRT-PCR and compared to published values determined by high-density oligonucleotide array and/or microarray analysis for snf2 and sin3. The 768-reaction kinetic thermalcyclers, each with a capacity for more than a half million assays per year, are well suited to genomics applications such as single nucleotide polymorphism/disease association studies and genomewide transcription profiling where high sensitivity and accuracy are required.

Interaction between Transcription Elongation Factors and mRNA 3′-End Formation at the Saccharomyces cerevisiae GAL10-GAL7 Locus

Spt6 is a conserved transcription factor that associates with RNA polymerase II (pol II) during elongation. Spt6 is essential for viability in Saccharomyces cerevisiae and regulates chromatin structure during pol II transcription. Here we present evidence that mutations that impair Spt6, a second elongation factor, Spt4, and pol II can affect 3'-end formation at GAL10. Additional analysis suggests that Spt6 is required for cotranscriptional association of the factor Ctr9, a member of the Paf1 complex, with GAL10 and GAL7, and that Ctr9 association with chromatin 3' of GAL10 is regulated by the GAL10 polyadenylation signal. Overall, these results provide new evidence for a connection between the transcription elongation factor Spt6 and 3'-end formation in vivo.

PrimerSelect: a transcriptome-wide oligonucleotide primer pair design program for kinetic RT-PCR-based transcript profiling

We describe PrimerSelect, a program capable of transcriptome-wide design of primer pairs for optimal performance in kinetic reverse-transcriptase polymerase chain reaction (RT-PCR). For the yeast Saccharomyces cerevisiae, PrimerSelect designs primer pairs for 86% of genomic open reading frames (ORFs) using design criteria we previously established to be optimal for kinetic RT-PCR (kRT-PCR)-based transcript quantitation. Primer pairs designed by PrimerSelect for 230 yeast ORFs were evaluated for primer dimer potential, PCR cyclewise yield, and cross-priming. Performance of 95% of these primer pairs is optimal with respect to primer dimer potential and PCR cyclewise yield for quantitating even the rarest yeast transcript. All of the primer pairs produced a single amplicon of the expected size from yeast genomic DNA template. The utility of PrimerSelect for designing primer pairs complementary to ORF sequences defined for multiple isolates of the human bacterial pathogens Helicobacter pylori and Staphylococcus aureus is also demonstrated.

Plasmodium falciparum infection of the placenta affects newborn immune responses

The effects of exposure to placental malaria infection on newborn immunological responses, in particular Th1/Th2 cytokines and antigen-presenting cell (APC) function, were compared between cord blood mononuclear cells (CBMC) from parasitized and non-parasitized placentas of Gambian women. Cells were analysed in vitro for their ability to respond to mitogens [phorbol myristate acetate (PMA)/ionomycin, phytohaemagglutinin (PHA)], a malaria-unrelated test antigen [purified protein derivative of Mycobacterium tuberculin[purified protein derivative (PPD)] and Plasmodium falciparum schizont extracts. Mitogens induced strong proliferation and secretion of high concentrations of both IL-13 and sCD30 in CBMC from both groups. Conversely, significantly lower amounts of IFN-gamma were induced in the parasitized group in response to low doses of PHA. Protein antigens induced very low amounts of all tested cytokines, in particular IFN-gamma. However, a significantly higher release of sCD30 was observed in response to schizont extracts in the parasitized group. Addition of LPS to activate APC to low doses of PHA or schizont extracts increased the IFN-gamma production in both groups but levels remained lower in CBMC from the parasitized group. This result correlates with the lower production of IL-12 found following lipopolysaccharide (LPS) stimulation in this group. Taken together, these data show that placental infection with P. falciparum affects Th1 differentiation and sCD30 priming of neonatal lymphocytes and that the probable mode of action is via APC.

Enzymatic function of loop movement in enolase: preparation and some properties of H159N, H159A, H159F, and N207A enolases

The hypothesis that His159 in yeast enolase moves on a polypeptide loop to protonate the phosphoryl of 2-phosphoglycerate to initiate its conversion to phosphoenolpyruvate was tested by preparing H159N, H159A, and H159F enolases. These have 0.07%-0.25% of the native activity under standard assay conditions and the pH dependence of maximum velocities of H159A and H159N mutants is markedly altered. Activation by Mg2+ is biphasic, with the smaller Mg2+ activation constant closer to that of the "catalytic" Mg2+ binding site of native enolase and the larger in the mM range in which native enolase is inhibited. A third Mg2+ may bind to the phosphoryl, functionally replacing proton donation by His159. N207A enolase lacks an intersubunit interaction that stabilizes the closed loop(s) conformation when 2-phosphoglycerate binds. It has 21% of the native activity, also exhibits biphasic Mg2+ activation, and its reaction with the aldehyde analogue of the substrate is more strongly inhibited than is its normal enzymatic reaction. Polypeptide loop(s) closure may keep a proton from His159 interacting with the substrate phosphoryl oxygen long enough to stabilize a carbanion intermediate.

Ramsey fringes in a Bose-Einstein condensate between atoms and molecules

In a recent experiment, a Feshbach scattering resonance was exploited to observe Ramsey fringes in a 85Rb Bose-Einstein condensate. The oscillation frequency corresponded to the binding energy of the molecular state. We show that the observations are remarkably consistent with predictions of a resonance field theory in which the fringes arise from oscillations between atoms and molecules.

Transcript abundance in yeast varies over six orders of magnitude

In the current era of functional genomics, it is remarkable that the intracellular range of transcript abundance is largely unknown. For the yeast Saccharomyces cerevisiae, hybridization-based complexity analysis and SAGE analysis showed that the majority of yeast mRNAs are present at one or fewer copies per cell; however, neither method provides an accurate estimate of the full range of low abundance transcripts. Here we examine the range of intracellular transcript abundance in yeast using kinetically monitored, reverse transcriptase-initiated PCR (kRT-PCR). Steady-state transcript levels encoded by all 65 genes on the left arm of chromosome III and 185 transcription factor genes are quantitated. Abundant transcripts encoded by glycolytic genes, previously quantitated by kRT-PCR, are present at a few hundred copies per cell whereas genes encoding physiologically important transcription factors are expressed at levels as low as one-thousandth transcript per cell. Of the genes assessed, only the silent mating type loci, HML and HMR, are transcriptionally silent. The results show that transcript abundance in yeast varies over six orders of magnitude. Finally, kRT-PCR, cDNA microarray, and high density oligonucleotide array assays are compared for their ability to detect and quantitate the complete yeast transcriptome.

Signatures of resonance superfluidity in a quantum Fermi gas

We predict a direct and observable signature of the superfluid phase in a quantum Fermi gas, in a temperature regime already accessible in current experiments. We apply the theory of resonance superfluidity to a gas confined in a harmonic potential and demonstrate that a significant increase in density will be observed in the vicinity of the trap center.

Quantitation of Na+-K+-2Cl- cotransport splice variants in human tissues using kinetic polymerase chain reaction

A kinetic reverse transcription-polymerase chain reaction (RT-PCR)-based assay is described that can discriminate and quantitate differentially spliced mRNAs. This assay should be generally applicable for high-throughput quantitation of differentially spliced transcripts. The utility of this method was assessed for spliced transcripts encoded by the human Na+-K+-2Cl- cotransporter gene hNKCC1. Evidence is presented that the NKCC1 isoform of the human Na+-K+-2Cl- cotransporter is differentially spliced analogous to that recently described for the mouse Na+-K+-2Cl- cotransporter gene BSC2. The nucleotide sequences of the two human splice variants predict Na+-K+-2Cl- cotransporter proteins differing only in length. Stable transfectants expressing these human splice variants, designated NKCC1a or NKCC1b, were constructed. Both splice variants produce functional Na+-K+-2Cl- cotransporters in vivo. The abundance of NKCC1 mRNA and patterns of differential splicing in 10 different tissue types and three cell lines were quantitated using the kRT-PCR assay. The results showed that the total amount of NKCC1 mRNA varied by more than 30-fold in the human tissues and cell lines examined. The ratio of NKCC1a/NKCC1b varied nearly 70-fold among these same tissues and cell lines suggesting that differential splicing of the NKCC1 transcript may play a regulatory role in human tissues.

The H159A mutant of yeast enolase 1 has significant activity

The function of His159 in the enolase mechanism is disputed. Recently, Vinarov and Nowak (Biochemistry (1999) 38, 12138-12149) prepared the H159A mutant of yeast enolase 1 and expressed this in Escherichia coli. They reported minimal (ca. 0.01% of the native value) activity, though the protein appeared to be correctly folded, according to its CD spectrum, tryptophan fluorescence, and binding of metal ion and substrate. We prepared H159A enolase using a multicopy plasmid and expressed the enzyme in yeast. Our preparations of H159A enolase have 0.2-0.4% of the native activity under standard assay conditions and are further activated by Mg(2+) concentrations above 1 mM to 1-1.5% of the native activity. Native enolase 1 (and enolase 2) are inhibited by such Mg(2+) concentrations. It is possible that His159 is necessary for correct folding of the enzyme and that expression in E. coli leads to largely misfolded protein.

Proteins secreted by the parasitic nematode Nippostrongylus brasiliensis act as adjuvants for Th2 responses

Infections with parasitic helminths such as Nippostronglyus brasiliensis induce dominant type 2 responses from antigen-specific T helper cells. The potency of the Th2 bias can also drive Th2 responses to bystander antigens introduced at the same time as infection. We now report that the Th2-promoting effect of infection can be reproduced with soluble N. brasiliensis excretory-secretory proteins (NES) released by adult parasites in vitro. Immunization of BALB/c mice with NES results in the production of IL-4 with elevated total serum IgE and specific IgG1 antibodies. NES is also able to stimulate IL-4 and polyclonal IgE production in other mouse strains (C57BL/6, B10.D2, CBA). These features are seen whether NES is administered without adjuvant as soluble protein in phosphate-buffered saline or with complete Freund's adjuvant which normally favors Th1 responses. Thus, NES possesses intrinsic adjuvanticity. Moreover, co-administration of hen egg lysozyme (HEL) with NES in the absence of other adjuvants results in generation of HEL-specific lymphocyte proliferation, IL-4 release and IgG1 antibody responses, documenting that NES can act as an adjuvant for third-party antigens. Proteinase K digestion or heat treatment of NES before immunization abolished the IL-4-stimulating activity, indicating that the factors acting to promote Th2 induction are proteins secreted by the adult parasite.

High-throughput SNP allele-frequency determination in pooled DNA samples by kinetic PCR

We have developed an accurate, yet inexpensive and high-throughput, method for determining the allele frequency of biallelic polymorphisms in pools of DNA samples. The assay combines kinetic (real-time quantitative) PCR with allele-specific amplification and requires no post-PCR processing. The relative amounts of each allele in a sample are quantified. This is performed by dividing equal aliquots of the pooled DNA between two separate PCR reactions, each of which contains a primer pair specific to one or the other allelic SNP variant. For pools with equal amounts of the two alleles, the two amplifications should reach a detectable level of fluorescence at the same cycle number. For pools that contain unequal ratios of the two alleles, the difference in cycle number between the two amplification reactions can be used to calculate the relative allele amounts. We demonstrate the accuracy and reliability of the assay on samples with known predetermined SNP allele frequencies from 5% to 95%, including pools of both human and mouse DNAs using eight different SNPs altogether. The accuracy of measuring known allele frequencies is very high, with the strength of correlation between measured and known frequencies having an r(2) = 0.997. The loss of sensitivity as a result of measurement error is typically minimal, compared with that due to sampling error alone, for population samples up to 1000. We believe that by providing a means for SNP genotyping up to thousands of samples simultaneously, inexpensively, and reproducibly, this method is a powerful strategy for detecting meaningful polymorphic differences in candidate gene association studies and genome-wide linkage disequilibrium scans.

Transcript quantitation in total yeast cellular RNA using kinetic PCR

Kinetically monitored, reverse transcriptase-initiated PCR (kinetic RT-PCR, kRT-PCR) is a novel application of kinetic PCR for high throughput transcript quantitation in total cellular RNA. The assay offers the simplicity and flexibility of an enzyme assay with distinct advantages over DNA microarray hybridization and SAGE technologies for certain applications. The reproducibility, sensitivity and accuracy of the kRT-PCR were assessed for yeast transcripts previously quantitated by a variety of methods including SAGE analysis. Changes in transcript levels between different genetic or physiological cell states were reproducibly quantitated with an accuracy of +/-20%. The assay was sufficiently sensitive to quantitate yeast transcripts over a range of more than five orders of magnitude, including low abundance transcripts encoding cell cycle and transcriptional regulators.

Vaccination against helminth parasites--the ultimate challenge for vaccinologists?

Helminths are multicellular pathogens which infect vast numbers of human and animal hosts, causing widespread chronic disease and morbidity. Vaccination against these parasites requires more than identification of effective target antigens, because without understanding the immunology of the host-parasite relationship, ineffective immune mechanisms may be invoked, and there is a danger of amplifying immunopathogenic responses. The fundamental features of the immune response to helminths are therefore summarised in the context of vaccines to helminth parasites. The contention between type-1 and type-2 responses is a central issue in helminth infections, which bias the immune system strongly to the type-2 pathway. Evidence from both human and experimental animal infections indicates that both lineages contribute to immunity in differing circumstances, and that a balanced response leads to the most favourable outcome. A diversity of immune mechanisms can be brought to bear on various helminth species, ranging from antibody-independent macrophages, antibody-dependent granulocyte killing, and nonlymphoid actions, particularly in the gut. This diversity is highlighted by analysis of rodent infections, particularly in comparisons of cytokine-depleted and gene-targeted animals. This knowledge of protective mechanisms needs to be combined with a careful choice of parasite antigens for vaccines. Many existing candidates have been selected with host antibodies, rather than T-cell responses, and include a preponderance of highly conserved proteins with similarities to mammalian or invertebrate antigens. Advantage has yet to be taken of parasite genome projects, or of directed searches for novel, parasite-specific antigens and targets expressed only by infective stages and not mature forms which may generate immunopathology. With advances under way in parasite genomics and new vaccine delivery systems offering more rapid assessment and development, there are now excellent opportunities for new antihelminth vaccines.

Plinth padding confounds measures of posteroanterior spinal stiffness

This study investigated whether the presence of plinth padding influences measured posteroanterior spinal stiffness. Two measures of posteroanterior stiffness, the slope of the loading curve (K) and the displacement at 30 N (D30) were made at three vertebral levels: L3, T12 and T6, on a rigid and a padded plinth in 24 asymptomatic subjects. Analysis of variance demonstrated a significant reduction in K and increase in D30 when measured on the padded compared to the rigid surface and an interaction effect for both the K and D30 measures, indicating that the effect of the padding depends upon the vertebral level tested. The correlations between the padded and unpadded stiffness measures ranged from 0.70 to 0.87. The data from this study suggest that the type of plinth surface needs to be standardised when evaluating PA stiffness.

Early interleukin-4: its role in the switch towards a Th2 response and IgE-mediated allergy

The etiology of IgE-mediated allergies is complex and, thus far, not completely understood. A common feature, however, is the overproduction of IgE-inducing cytokines, e.g. interleukin-4(IL-4), compared to IgE-antagonistic cytokines, such as interferon-gamma or IL-12. IgE-inducing cytokines are produced by T helper type 2 (Th2) cells. The differentiation of naive T cells towards the Th2 phenotype seems to be crucially dependent upon the particular cytokines present in the early stages of an immune response. Concerning the factors driving Th2 differentiation, the so-called 'early IL-4' seems to play an important role, although there is some controversy over the degree of its requirement and its cellular source. We have recently demonstrated that basophils might be such a source, since they rapidly release IL-4 upon antigen-specific or nonantigen-specific stimuli, such as certain lectins. This makes lectins interesting candidates for inducing a Th2 response and IgE-mediated allergy in unsensitized individuals.

Jaagsiekte retrovirus is widely distributed both in T and B lymphocytes and in mononuclear phagocytes of sheep with naturally and experimentally acquired pulmonary adenomatosis

Jaagsiekte sheep retrovirus (JSRV) is a type D retrovirus specifically associated with a contagious lung tumor of sheep, sheep pulmonary adenomatosis (SPA). JSRV replicates actively in the transformed epithelial cells of the lung, and JSRV DNA and RNA have been detected in lymphoid tissues of naturally affected animals. To determine the lymphoid target cells of JSRV, CD4(+) T cells, CD8(+) T cells, B lymphocytes, and adherent cell (macrophage/monocyte) populations were isolated from the mediastinal lymph nodes of naturally affected sheep and lambs inoculated with JSRV. Cells were enriched to high purity and then analyzed for JSRV proviral DNA by heminested PCR, and the proviral burden was quantitated by limiting dilution analysis. JSRV proviral DNA was found in all subsets examined but not in appropriate negative controls. In sheep naturally affected with SPA, JSRV proviral burden was greatest in the adherent cell population. In the nonadherent lymphocyte population, surface immunoglobulin-positive B cells contained the greatest proviral burden, while CD4(+) and CD8(+) T cells contained the lowest levels of JSRV proviral DNA. In most of the cases (5 of 8), provirus also could be detected in the peripheral blood mononuclear cell (PBMC) population. A kinetic study of JSRV infection in the mediastinal lymphocyte population of newborn lambs inoculated with JSRV found that JSRV proviral DNA could be detected as early as 7 days postinoculation before the onset of pulmonary adenomatosis, although the proviral burden was greatly reduced compared to adult natural cases. This was reflected in the levels found in PBMC since proviral DNA was detected in 2 of 13 animals. At the early time points studied (7 to 28 days postinoculation) no one subset was preferentially infected. These data indicate that JSRV can infect lymphoid and phagocytic mononuclear cells of sheep and that dissemination precedes tumor formation. Infection of lymphoid tissue, therefore, may play an important role in the pathogenesis of SPA.

Parasite immunology: pathways for expelling intestinal helminths

Helminth parasites induce strong immune responses that are initiated by cytokines, in the first instance interleukin-4 and interleukin-13. Recent studies of knockout mice deficient in these mediators or their shared receptor have revealed discrete pathways required for expulsion of different gut parasites.

Significance of the enzymatic properties of yeast S39A enolase to the catalytic mechanism

The S39A mutant of yeast enolase (isozyme 1), prepared by site-directed mutagenesis, has a relative Vmax of 0.01% and an activation constant for Mg2+ ca. 10-fold higher, compared with native enzyme. It is correctly folded. There is little effect of solvent viscosity on activity. We think that the loop Ser36-His43 fails to move to the 'closed' position upon catalytic Mg2+ binding, weakening several electrostatic interactions involved in the mechanism.

Inhibition of virus-encoded thymidine kinase suppresses herpes simplex virus replication in vitro and in vivo

Both herpes simplex virus type 1 (HSV-1) and HSV-2 encode a thymidine kinase enzyme which differs from cellular thymidine kinase in substrate specificity. Viral thymidine kinase enables the virus to replicate in cells that lack cellular thymidine kinase, namely those of the sensory neurons where the virus establishes, and periodically reactivates from, a latent state. Thymidine kinase-dependent HSV replication following viral reactivation at the site of latency is thought to precede the emergence of virus at mucosal surfaces. The ability to inhibit such an essential viral enzyme would potentially prevent HSV from replicating within neuronal tissue, and thus stop the recurrent disease cycle. Ro 32-2313 was designed as a selective and competitive inhibitor of HSV thymidine kinase and in vitro studies have confirmed this mechanism of action. In vivo evaluation of a soluble prodrug of Ro 32-2313, Ro 32-4397, was undertaken in murine models where pathogenesis was dependent upon viral replication in neuronal tissue. It was shown that in vivo administration of Ro 32-4397 (i) significantly reduced the viral titre detected in isolated dorsal root ganglia; (ii) prevented HSV-2-induced lethality in a systemic infection model; and (iii) reduced zosteriform lesion development in a model of dermal infection. Administration of Ro 32-4397 produced dose-related changes in viral pathogenicity towards those of the phenotype of a thymidine kinase-deficient virus. Overall, the study confirmed that thymidine kinase inhibitors can suppress the replication of HSV in vivo, and suggest that such inhibitors may reduce reactivation of the virus from latency if used prophylactically in recurrent HSV infection.

Antibody response to the 60-kDa chlamydial heat-shock protein is associated with scarring trachoma

To determine if serum antibody response to the 60-kDa chlamydial heat-shock protein (Chsp60) was associated with scarring trachoma, responses to Chlamydia trachomatis and to Chsp60 from 148 Gambian subjects with trachomatous scarring and from 148 controls without clinical evidence of disease from trachoma-endemic communities were characterized. Chsp60 response was found in 32% of cases and 16% of controls (P < .001). Although C. trachomatis titer was also higher in cases than controls, the prevalence of Chsp60 response between the 2 groups remained significantly different after stratifying for C. trachomatis titer (weighted odds ratio [OR] = 2.1, P = .02). Chsp60 response and C. trachomatis serovar A titer of > or =128 were independently associated with scarring trachoma. The presence of HLA class II allele DRB1*0701 was positively correlated with Chsp60 response (OR = 2.6, P = .02), and DQB1*0301 and DQB1*0501 were negatively associated (OR = 0.42, P < .001; OR = 0.55, P = .46, respectively).

Rat liver transcript profiling in normal and disease states using a kinetic polymerase chain reaction assay

Synthesis of a number of rat liver proteins, including albumin, fibrinogen, apolipoprotein AI, and transferrin, is elevated in the nephrotic syndrome (NS). Increased synthesis of these proteins is regulated at the transcriptional level and occurs in the context of increased mRNA encoding each protein. Changes in albumin, fibrinogen, apolipoprotein AI, and transferrin mRNA levels in total cellular RNA isolated from the livers of normal rats and rats with passive Heymann nephritis were measured using a kinetically monitored, reverse transcriptase-initiated PCR (kRT-PCR) assay. The kRT-PCR assay rapidly quantitated changes in rat liver mRNA levels with an accuracy comparable to that of more labor-intensive mRNA quantitation methods. The relative levels of beta-actin, apolipoprotein AI, fibrinogen, and albumin mRNAs were very similar in total cellular RNA isolated from rat liver versus H4C3 hepatocytes in culture, suggesting that the H4C3 hepatocyte is an appropriate model for studying expression of genes encoding proteins secreted by the liver. Taken together, the results demonstrate the feasibility of using the kRT-PCR assay for isolation and characterization of a soluble factor responsible for elevated synthesis of hepatocyte mRNAs associated with the nephrotic syndrome.

Effect of site-directed mutagenesis of His373 of yeast enolase on some of its physical and enzymatic properties

The X-ray structure of yeast enolase shows His373 interacting with a water molecule also held by residues Glu168 and Glu211. The water molecule is suggested to participate in the catalytic mechanism (Lebioda, L. and Stec, B. (1991) Biochemistry 30, 2817-2822). Replacement of His373 with asparagine (H373N enolase) or phenylalanine (H373F enolase) reduces enzymatic activity to ca. 10% and 0.0003% of the native enzyme activity, respectively. H373N enolase exhibits a reduced Km for the substrate, 2-phosphoglycerate, and produces the same absorbance changes in the chromophoric substrate analogues TSP1 and AEP1, relative to native enolase. H373F enolase binds AEP less strongly, producing a smaller absorbance change than native enolase, and reacts very little with TSP. H373F enolase dissociates to monomers in the absence of substrate; H373N enolase subunit dissociation is less than H373F enolase but more than native enolase. Substrate and Mg2+ increase subunit association in both mutants. Differential scanning calorimetric experiments indicate that the interaction with substrate that stabilizes enolase to thermal denaturation involves His373. We suggest that the function of His373 in the enolase reaction may involve hydrogen bonding rather than acid/base catalysis, through interaction with the Glu168/Glu211/H2O system, which produces removal or addition of hydroxyl at carbon-3 of the substrate.

Scarring trachoma is associated with polymorphism in the tumor necrosis factor alpha (TNF-alpha) gene promoter and with elevated TNF-alpha levels in tear fluid

Tumor necrosis factor alpha (TNF-alpha) may play a central role in the disease pathogenesis which occurs as a consequence of chlamydial infection. To investigate the importance of TNF-alpha gene promoter polymorphisms and TNF-alpha levels in tear fluid in scarring trachoma, a large matched-pair case-control study was performed in The Gambia. The -308A allele was present in a higher proportion of patients (28.4%) than controls (18.4%), with an increasing association for homozygotes (chi2 for trend, P = 0.032; allele frequency, 0.163 in patients and 0.099 in controls; chi2, P = 0.025). For the -238A allele, the association was similar but not significant. The disease association was highly significant when the number of either -308A or -238A sites in an individual was considered (P = 0.003). TNF-alpha promoter alleles are tightly linked to some HLA class I and II alleles, but multivariate analysis confirmed that the disease associations were independent of HLA, although a class I allele, A*6802, is also associated with disease. TNF-alpha was more frequently detected in tear samples from patients (27.6%) than from controls (15.9%), increasingly so for higher levels of detectable TNF-alpha (P = 0.015). Among patients, detectable TNF-alpha in tears was highly associated with the presence of ocular chlamydial infection (P < 0.001). The results indicate that TNF-alpha plays a major role in the tissue damage and scarring which occurs as a consequence of Chlamydia trachomatis infection.

Synthetic peptides based on Chlamydia trachomatis antigens identify cytotoxic T lymphocyte responses in subjects from a trachoma-endemic population

CD8+ cytotoxic T lymphocytes (CTL) recognize peptide antigens in the context of class I MHC antigen molecules. To identify peptides capable of eliciting anti-Chlamydia trachomatis CTL responses, 13 synthetic peptides conforming to human leucocyte antigen (HLA)-B8- or -B35-predicted binding motifs were synthesized using sequences based on C. trachomatis major outer membrane protein (MOMP) and heat shock protein 60 (hsp60). Two of 11 HLA-B35-predicted binding peptides were able to stabilize HLA-B35 in an in vitro binding assay. All peptides were tested in CTL assays using peripheral blood mononuclear cells (PBMC) isolated from 26 HLA-B8 or -B35 individuals resident in a trachoma-endemic community. Responses to MOMP and hsp60 peptides were identified in a minority of both HLA-B8 and -B35 individuals. Two of 12 HLA-B8 subjects responded to MOMP and 1/13 to hsp60 peptides. Responses in HLA-B35 subjects were similar, 1/13 subjects responding to MOMP and 2/13 to hsp60 peptides. CTL responses were observed only in children resolving current infection and in adults without scarring of the conjunctiva. These results suggest that anti-chlamydial CTL occur at low levels in peripheral blood, but may be important in the resolution of naturally acquired human ocular chlamydial infection.

Jaagsiekte retrovirus establishes a disseminated infection of the lymphoid tissues of sheep affected by pulmonary adenomatosis

Jaagsiekte retrovirus (JSRV) is an exogenous type D-related retrovirus specifically associated with a contagious lung cancer of sheep (sheep pulmonary adenomatosis; SPA). Recently, epithelial tumour cells in the lungs of SPA-affected sheep were identified as major sites of JSRV replication by immunological techniques and RT-PCR amplification of part of JSRV gag. JSRV was not detected outside the lungs and their draining lymph nodes. However, low levels of JSRV expression in non-respiratory tissues could have been masked by co-amplification of endogenous JSRV-related sequences, which were differentiated from JSRV by the lack of a Scal restriction site in the PCR product. To further investigate the pathogenesis of SPA, an exogenous virus-specific hemi-nested PCR was developed utilizing primers in the U3 region of JSRV LTR, where major differences between endogenous and exogenous sequences exist. This technique was shown to be > or = 10(5)-fold more sensitive than the previous gag PCR/ScaI digestion method. Using this new assay the tissue distribution of JSRV in sheep with natural and experimentally induced SPA was analysed. Proviral DNA and JSRV transcripts were found in all tumours and lung secretions of SPA-affected sheep (n = 22) and in several lymphoid tissues. The mediastinal lymph nodes draining the lungs were consistently demonstrated to be infected by JSRV (10/10). JSRV transcripts were also detected in spleen (7/9), thymus (2/4), bone marrow (4/8) and peripheral blood mononuclear cells (3/7). Proviral DNA was also detected in these tissues although in a much lower proportion of cases. JSRV was not detected in 27 samples from unaffected control animals (n = 15).

HLA class I and II polymorphisms and trachomatous scarring in a Chlamydia trachomatis-endemic population

Immune responses to Chlamydia trachomatis contribute to protection from infection and to immunopathologic disease. To test whether subjects' HLA class I (A, B, and Cw) or class II (DRbeta1 and DQbeta1) types influence risk of trachomatous scarring from chronic infection with C trachomatis, 153 cases and pair-matched controls in Gambia were studied. No HLA type was associated with protection from scarring, indicating that protective immune responses are not limited to only one or a few HLA-restricted epitopes in C. trachomatis antigens. One class I antigen, HLA-A28, was significantly more common among cases than controls (25.8% vs. 15.9%, respectively; McNemar's odds ratio [OR], 1.88; 95% confidence interval [CI] = 1.01-3.49; P = .046). In DNA subtyping of the A28 specificity, the A*6801 allele was equally common among cases and controls, but the A*6802 allele was significantly overrepresented among cases (McNemar's OR, 3.14; 95% CI = 1.32-7.44; P = .009). This association may be due to an immunopathologic HLA-A*6802-restricted cytotoxic T lymphocyte response.