Anti-neutrophil cytoplasmic antibodies (ANCA) from patients with systemic vasculitis recognize restricted epitopes of proteinase 3 involving the catalytic site

ANCA with specificity for proteinase 3 (PR3), a neutrophil primary granule enzyme, are of diagnostic value in Wegener's granulomatosis (WG) and certain other forms of systemic vasculitis. There is evidence to suggest that they play a pathogenic role in disease, and that the interaction of ANCA with PR3 is likely to be important. We showed, using a resonant mirror biosensor, that C-ANCA from different patients recognized the same or closely related epitopes on PR3. Studies using linear peptides in the SPOT system confirmed the highly restricted nature of this interaction and identified five linear epitopes. Fluid-phase inhibition studies, using a different set of peptides, validated the sequences involved. Using a computer-generated model of the structure of PR3, four of five epitopes were shown to be intimately linked with the catalytic site. The restricted number of epitopes, and their location at the catalytic site, has important implications for the role of C-ANCA in the pathogenesis of vasculitis.

PETAL LOSS gene regulates initiation and orientation of second whorl organs in the Arabidopsis flower

PETAL LOSS is a new class of flower development gene whose mutant phenotype is confined mostly to the second whorl. Two properties are disrupted, organ initiation and organ orientation. Initiation is frequently blocked, especially in later-formed flowers, or variably delayed. The few petals that arise occupy a wider zone of the flower primordium than normal. Also, a minority of petals are trumpet-shaped, thread-like or stamenoid. Studies of ptl combined with homeotic mutants have revealed that the mutant effect is specific to the second whorl, not to organs with a petal identity. We propose that the PTL gene normally promotes the induction of organ primordia in specific regions of the second floral whorl. In ptl mutants, these regions are enlarged and organ induction is variably reduced, often falling below a threshold. A dominant genetic modifier of the ptl mutant phenotype was found in the Landsberg erecta strain that significantly boosts the mean number of petals per flower, perhaps by reinforcing induction so that the threshold is now more often reached. The second major disruption in ptl mutants relates to the orientation adopted by second whorl organs from early in their development. In single mutants the full range of orientations is seen, but when B function (controlling organ identity) is also removed, most second whorl organs now face outwards rather than inwards. Orientation is unaffected in B function single mutants. Thus petals apparently perceive their orientation within the flower primordium by a mechanism requiring PTL function supported redundantly by that of B class genes.

Reducing the rate of nosocomially transmitted respiratory syncytial virus

BACKGROUND

A large number (17) of nosocomial respiratory syncytial virus cases led to the development of control measures to prevent transmission of respiratory syncytial virus (RSV) within the Johns Hopkins Hospital's Children's Center.

METHODS

The control plan is based on a 2-stage process. In stage 1, the staff are notified that RSV is in the community, and information is distributed through a communication tree. Stage 2 requires that nasopharyngeal aspirates be obtained from all children <3 years of age who have respiratory symptoms. The aspirates are tested directly for RSV antigen and cultured for RSV. The children are placed on pediatric droplet precautions pending those results.

RESULTS

The proportion of nosocomial RSV cases dropped from 16.5% before the use of RSV control measures to 7.2% after the initiation of the control program. A case of RSV identified in the hospital was 2.6 times more likely to be nosocomially acquired before the intervention compared with after the intervention. Approximately 14 cases of RSV are prevented each year, which results in a savings of 56 hospital-days and more than $84,000 in direct hospital-related charges alone.

CONCLUSIONS

The nosocomial spread of RSV can be reduced by a specific and feasible control plan that includes early identification and rapid isolation of potential RSV cases.

HLA genes in ANCA-associated vasculitides

Primary systemic vasculitis affecting smaller vessels is usually associated with antineutrophil cytoplasmic antibodies (ANCA). The ANCA-associated vasculitides include Wegener's granulomatosis, microscopic polyangiitis, Churg Strauss syndrome and renal limited vasculitis. There is considerable evidence that genetic factors influence susceptibility to ANCA-associated vasculitis, including reports of familial cases, differences in racial incidence, and associations with polymorphic variants of proteins such as alpha-1-antitrypsin. There is mounting evidence, from clinical and in vitro studies, that ANCA may be pathogenic. However, it is also clear that autoreactive T cells are likely to be involved, by providing T cell help for ANCA production and possibly by producing cell-mediated immune injury. Indeed, T cells from patients with vasculitis have been shown to proliferate in vitro in response to the target antigens of ANCA - proteinase 3 and myeloperoxidase. In most T-cell-dependent autoimmune diseases there are clear positive and/or negative associations with HLA genes. These genes are encoded in the major histocompatibility complex (MHC) and their products, the HLA molecules, play a central role in the generation of T cell responses. For this reason, many investigators have looked for HLA associations in ANCA-associated vasculitides. Problems in analysing these reports include the definition of the diseases concerned, and the varying methodology of HLA typing. A number of positive and negative associations with HLA genes have been reported in systemic vasculitis. However, it is striking that no consistent association has been identified in different series. In recent studies there have been positive associations with HLA DR1, DQw7 or DR8, negative associations with DR3 or DR13, or no significant associations. This lack of an obvious and consistent HLA association is extremely interesting, and suggests that the T cell response in vasculitis may be very heterogeneous, or that a genuine strong association has yet to be identified. Further investigation of this problem is clearly needed to improve our understanding of the pathogenesis of ANCA-associated vasculitides.

Pseudoseizures, families, and unspeakable dilemmas

Fourteen videotaped family interviews of patients with diagnosed pseudoseizures were studied to determine the relationship of the symptoms to unspeakable dilemmas as forced choices imposed by family or social circumstances under conditions that also require the ensuing distress to be hidden. An unspeakable dilemma was evident in 13 of 14 interviews, with the patient the most silent family member in 13 interviews. In six cases, there was revealed a realistic threat of physical or sexual assault to a person involved in the problem, although not always the patient. These findings point to an important role for family therapy skills in the evaluation and treatment of pseudoseizures.

Classification, pathogenesis, and treatment of systemic vasculitis

Patients with systemic vasculitis (SV), especially Wegener's granulomatosis and microscopic polyangiitis, regularly present with renal involvement. Although considered a rare disease, either the incidence of SV is increasing or it is being increasingly recognized. Accurate classification systems are required to allow comparison of data from different groups investigating and treating these patients. Systemic vasculitis is known to be an autoimmune disease, but the mechanisms of pathogenesis have not been established, despite many studies on this topic in recent years. Most of this work has been done in vitro, although development of animal models is underway. Patient and renal survival have improved with aggressive immunosuppressive treatment, but morbidity is high and controversies remain in establishing the most effective regimens with minimum adverse effects. In this review we discuss the classification of SV, review the current knowledge of pathogenic mechanisms, and consider the relative merits of different treatment protocols.

C-antineutrophil cytoplasmic antibody positivity in vasculitis patients is associated with the Z allele of alpha-1-antitrypsin, and P-antineutrophil cytoplasmic antibody positivity with the S allele

BACKGROUND

Antineutrophil cytoplasmic antibodies (ANCA) in vasculitis have either cANCA or pANCA patterns as defined by immunofluorescence. The target autoantigen of cANCA is usually proteinase 3 (PR3), whereas that of pANCA is usually myeloperoxidase (MPO). Alpha-1-antitrypsin (alpha 1AT) is the major physiological inhibitor of PR3, while MPO is an inhibitor of alpha 1AT.

METHODS

To determine whether there was an association between ANCA positive vasculitis, ANCA pattern, and alpha 1AT deficiency alleles, we studied alpha 1AT phenotypes of 99 cANCA and 99 pANCA positive vasculitis patients by isoelectric focusing and immunoblotting, and compared them with 2310 controls from the same geographical area.

RESULTS

C-ANCA patients showed an increased frequency of the Z allele (0.055 versus 0.018 in controls), conferring a relative risk of 3. They showed no increase in frequency of the S allele. P-ANCA patients showed an increased frequency of the S allele (0.091 versus 0.046 in controls) conferring a relative risk of 2. The frequency of the Z allele also appeared to be increased (0.030 versus 0.018 in controls), but this was not statistically significant.

CONCLUSIONS

These findings demonstrate an association between ANCA-positive vasculitis and deficiency phenotypes of alpha 1AT, and suggest a role for alpha 1AT in the development of systemic vasculitis.

T cell responses to myeloperoxidase (MPO) and proteinase 3 (PR3) in patients with systemic vasculitis

T cell-mediated immune responses are likely to be important in the pathogenesis of systemic vasculitis. However, identifying the T cells involved has proved difficult, and there are conflicting reports regarding T cell proliferation in response to different autoantigens. Perinuclear (P) and cytoplasmic (C) anti-neutrophil cytoplasmic antibodies (ANCA) are closely associated with systemic vasculitis, and are generally specific for MPO or PR3, respectively. We studied the proliferative responses to MPO and PR3 of peripheral blood mononuclear cells from patients with P-ANCA or C-ANCA specific for these antigens by ELISA. These responses were compared with those of normal controls, and of disease controls with P- or C-ANCA not specific for MPO or PR3. The patient group as a whole showed significant T cell proliferation in response to the autoantigens compared with controls (P = 0.005). Cells from nine of 13 P-ANCA-positive, anti-MPO-positive patients proliferated in response to MPO, compared with five of 16 controls (P = 0.04). Cells from five of eight C-ANCA-positive, anti-PR3-positive patients proliferated in response to PR3, compared with two of 11 controls (P = 0.05). These experiments demonstrate that patients with P-ANCA or C-ANCA possess T cells which respond to MPO or PR3, respectively. As in other autoimmune diseases, responses to both antigens were also seen in a proportion of healthy controls. Further analysis of these responses will be important in understanding the pathogenesis of systemic vasculitis and in designing specific immunotherapy.

Stability of antimycobacterial drugs in susceptibility testing

Aqueous solutions of 0.02% isoniazid, 0.2% streptomycin, 0.2% para-aminosalicylate, and 0.5% ethambutol and ethylene glycol solutions of 0.5% ethionamide stored at 3 to 7 degrees C remained stable for 1 year, as did aqueous solutions of 0.05% ethionamide hydrochloride, 0.05% kanamycin, 0.05% viomycin, and 0.1% capreomycin stored at -20 degrees C. The ethambutol and capreomycin solutions were tested by microbiologic methods; the other solutions were tested by both spectrophotometric and microbiologic methods. Prepared susceptibility testing media made with cycloserine, rifampin, and the above solutions incorporated into Middlebrook 7H10 medium showed acceptable stability when stored at 3 to 7 degrees C for 1 month. During incubation of the test medium at 37 degrees C, approximately half of the activity of isoniazid, ethionamide, ethambutol, cycloserine, and rifampin was lost after periods ranging from 2 to 4 days for ethambutol to 2 weeks for rifampin.

Quality control of individual components used in Middlebrook 7H10 medium for mycobacterial susceptibility testing

The acceptability of different lots of commercial components which constitute our basal medium for susceptibility testing of mycobacteria was evaluated. The basal medium consisted of Middlebrook 7H10 agar supplemented with 10% oleic acid-albumin-dextrose-catalase and 0.5% glycerol. Studies were performed by using three separate microbiologic assays, and results were compared with parallel tests on previously standardized and acceptable lots of media. Components were rejected if comparison with standardized medium showed a major change in growth support or susceptibility status of any reference strain to any antimicrobial agent tested. Of the components tested in such a manner, 7 of 23 (30%) lots of 10% oleic acid-albumin-dextrose-catalase, 2 of 13 (15%) lots of Middlebrook 7H10 agar, and 0 of 5 lots of glycerol were found to be unacceptable. This study demonstrates that individual lots of components of this basal medium may vary significantly in their suitability for susceptibility testing, and failure to detect such variation may dramatically affect susceptibility profiles.

Urinary guanosine 3':5'-cyclic monophosphate but not tissue kallikrein follows the plasma atrial natriuretic factor response to acute volume expansion with saline

1. The relationship between plasma immunoreactive atrial natriuretic factor (Ir-ANF) and the urinary excretion of sodium, guanosine 3':5'-cyclic monophosphate (cyclic GMP) and of tissue kallikrein was examined in seven healthy female volunteers. 2. Each volunteer attended on two occasions, a control and a saline infusion day. On the infusion day saline (2 litres, 0.9% NaCl) was administered over 60 min. Measurements of plasma Ir-ANF and urinary excretion of sodium, cyclic GMP and of tissue kallikrein were made at 30 min intervals during the infusion and for 3 h after the infusion. 3. Mean (+/- SEM) urinary sodium excretion increased from a basal value (time 0) of 102 +/- 15 mumo/min to 222 +/- 47 mumol/min 60-90 min from the start of the infusion and thereafter remained significantly elevated (P less than 0.01) above sodium excretion on the control day. 4. In response to saline infusion there was a transient rise in mean (+/- SEM) plasma Ir-ANF from 6.7 +/- 0.8 pmol/l to a peak of 22.5 +/- 3.7 pmol/l at 75 min, falling to 12.7 +/- 1.9 pmol/l at 135 min. The peak plasma Ir-ANF level on the infusion day was significantly elevated (P less than 0.05) above the time-matched measurement on the control day. 5. Similarly, there was a transient rise in mean (+/- SEM) urinary cyclic GMP excretion on the infusion day from 30.9 +/- 4.4 fmol/min to 64.6 +/- 11.4 fmol/min during the 60-90 min collection period, returning to 43.7 +/- 14.5 fmol/min at 210-240 min.(ABSTRACT TRUNCATED AT 250 WORDS)

First isolation of Legionella gormanii from human disease

Legionella gormanii, previously isolated only from the environment, was grown from the bronchial brush specimen of a patient with pneumonia. The organism was characterized by serologic, biochemical, and DNA hybridization studies.

Surgery for corneal epithelial basement membrane dystrophy

Seventeen consecutive eyes with corneal epithelial basement membrane with symptoms of recurrent erosion and/or decreased vision were treated with corneal epithelial basement membranectomy. Younger patients tended to have recurrent erosion, whereas older patients had decreased vision. All patients' symptoms improved following surgery. Electron microscopy revealed reduplication of the corneal epithelial basal lamina.

Corneal epithelial basement membrane dystrophy

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Resistance to penicillin in mutants of a penicillinase-negative organism, Staphylococcus aureus H

Penicillin-resistant mutants of Staphylococcus aureus H were similar to the parent in their response to penicillin though proportionately more penicillin was required for a given effect. The mutants did not inactivate penicillin. Most of the penicillin-binding sites (presumed to be murein transpeptidase molecules) bound penicillin rapidly when exposed to a very low concentration of penicillin (0.1 mug/ml), and yet the mutants retained some functional murein transpeptidase even in the presence of 500 mug of penicillin per ml. An hypothesis based on (i) functional versus nonfunctional transpeptidase molecules and (ii) variations in accessibility to penicillin can explain these findings.