Optically Active Spin Defects in Few-Layer Thick Hexagonal Boron Nitride.

Optically active spin defects in hexagonal boron nitride (hBN) are promising quantum systems for the design of two-dimensional quantum sensing units offering optimal proximity to the sample being probed. In this Letter, we first demonstrate that the electron spin resonance frequencies of boron vacancy centers (V_{B}^{-}) can be detected optically in the limit of few-atomic-layer thick hBN flakes despite the nanoscale proximity of the crystal surface that often leads to a degradation of the stability of solid-state spin defects. We then analyze the variations of the electronic spin properties of V_{B}^{-} centers with the hBN thickness with a focus on (i) the zero-field splitting parameters, (ii) the optically induced spin polarization rate and (iii) the longitudinal spin relaxation time. This Letter provides important insights into the properties of V_{B}^{-} centers embedded in ultrathin hBN flakes, which are valuable for future developments of foil-based quantum sensing technologies.

Isotopic Control of the Boron-Vacancy Spin Defect in Hexagonal Boron Nitride.

We report on electron spin resonance (ESR) spectroscopy of boron-vacancy (V_{B}^{-}) centers hosted in isotopically engineered hexagonal boron nitride (hBN) crystals. We first show that isotopic purification of hBN with ^{15}N yields a simplified and well-resolved hyperfine structure of V_{B}^{-} centers, while purification with ^{10}B leads to narrower ESR linewidths. These results establish isotopically purified h^{10}B^{15}N crystals as the optimal host material for future use of V_{B}^{-} spin defects in quantum technologies. Capitalizing on these findings, we then demonstrate optically induced polarization of ^{15}N nuclei in h^{10}B^{15}N, whose mechanism relies on electron-nuclear spin mixing in the V_{B}^{-} ground state. This work opens up new prospects for future developments of spin-based quantum sensors and simulators on a two-dimensional material platform.

Gene interaction at HLA-DQ enhances autoantibody production in primary Sjögren's syndrome.

Primary Sjögren's syndrome is an autoimmune disorder characterized by dryness of the mouth and eyes. The human leukocyte antigen (HLA) locus DQ is related to the primary Sjögren's syndrome autoantibodies that bind the RNA proteins Ro/SSA and La/SSB. Both DQ1 and DQ2 alleles are associated with high concentrations of these autoantibodies. An analysis of all possible combinations at DQ has shown that the entire effect was due to heterozygotes expressing the DQ1 and DQ2 alleles. These data suggest that gene interaction between DQ1 and DQ2 (or alleles at associated loci), possibly from gene complementation of trans-associated surface molecules, influences the autoimmune response in primary Sjögren's syndrome.

Evidence for complement activation via the alternate pathway in skin diseases, I. Herpes gestationis, systemic lupus erythematosus, and bullous pemphigoid.

A patient with herpes gestationis, 6 of 6 patients with bullous pemphigoid, and 5 of 25 patients with systemic lupus erythematosus were found to have properdin deposited along the skin basement membrane.The patient with herpes gestationis demonstrated by immunofluorescence basement membrane deposition of C3 and C5 in the absence of C1q, immunoglobulins, and light chains. A second patient with herpes gestationis had C3 deposition with no demonstrable immunoglobulins or light chains. A thermolabile humoral factor(s) capable of depositing C3 (without C1q or C4) on normal skin basement membrane was found in the sera of both patients with herpes gestationis. No anti-basement membrane antibodies could be demonstrated in the sera of these patients.The patients with systemic lupus erythematosus and bullous pemphigoid who manifested properdin deposition also showed skin basement membrane deposits of C1q, C4, C3, C5, and immunoglobulins. C3 proactivator (C3PA) was also found deposited along the skin basement membrane of three patients with systemic lupus erythematosus and all six bullous pemphigoid patients. This study provides suggestive evidence that activation of complement is occurring via the alternate pathway in herpes gestationis. In systemic lupus erythematosus and bullous pemphigoid, both the classical (antibody) mediated activation of complement as well as the alternate pathway may be operative.

The immunopathology of herpes gestationis. Immunofluorescence studies and characterization of "HG factor".

Nine skin biopsies from seven herpes gestationis patients were studied by immunofluorescence (IF) techniques. Basement membrane zone (BMZ) deposition of C3 and properdin was present in all nine skin specimens, while IgG deposition was apparent in only one. With in vitro C3 IF staining, positive BMZ staining (HG factor activity) was noted with all seven of our patients' serum samples tested. By standard indirect IF staining, however, only one of these serum samples contained BMZ antibodies of the IgG type. Two cord serum samples, tested by these same methods, yielded positive in vitro C3 staining (HG factor activity) but negative indirect IF staining (IgG). HG factor activity was found to be stable at 56 degrees C for 30 min and in two of three specimens at 56 degrees C for 1 h. Treatment of the complement source (normal human serum) used in the in vitro C3 staining assay with Mg2-EGTA or use of C2-deficient serum as the complement source inhibited HG factor activity. HG factor blocked the specific staining of the BMZ of normal human skin by labeled bullous pemphigoid antibodies. By sucrose density gradient ultracentrifugation and gel chromatography (Sephadex G-200), HG factor activity eluted with IgG-containing fractions. The highly purified IgG fraction of two herpes gestationis sera was also positive for HG factor activity. Our studies suggest that HG factor is an IgG antibody that may not be demonstrable by conventional IF methods, but which activates the classical complement pathway.

Autoimmune-associated congenital heart block: demographics, mortality, morbidity and recurrence rates obtained from a national neonatal lupus registry.

OBJECTIVES: The present study describes the demographics, mortality, morbidity and recurrence rates of autoimmune-associated congenital heart block (CHB) using information from the Research Registry for Neonatal Lupus. BACKGROUND: Isolated CHB detected at or before birth is strongly associated with maternal autoantibodies to 48-kD SSB/La, 52-kD SSA/Ro and 60-kD SSA/Ro ribonucleoproteins and is a permanent manifestation of the neonatal lupus syndromes (NLS). Available data are limited by the rarity of the disease. RESULTS: The cohort includes 105 mothers whose sera contain anti-SSA/Ro or anti-SSB/La antibodies, or both, and their 113 infants diagnosed with CHB between 1970 and 1997 (56 boys, 57 girls). Of 87 pregnancies in which sufficient medical records were available, bradyarrhythmia confirmed to be CHB was initially detected before 30 weeks of gestation in 71 (82%) (median time 23 weeks). There were no cases in which major congenital cardiac anatomic defects were considered causal for the development of CHB; in 14 there were minor abnormalities. Twenty-two (19%) of the 113 children died, 16 (73%) within 3 months after birth. Cumulative probability of 3-year survival was 79%. Sixty-seven (63%) of 107 live-born children required pacemakers: 35 within 9 days of life, 15 within 1 year, and 17 after 1 year. Forty-nine of the mothers had subsequent pregnancies: 8 (16%) had another infant with CHB and 3 (6%) had a child with an isolated rash consistent with NLS. CONCLUSIONS: Data from this large series substantiate that autoantibody-associated CHB is not coincident with major structural abnormalities, is most often identified in the late second trimester, carries a substantial mortality in the neonatal period and frequently requires pacing. The recurrence rate of CHB is at least two- to three-fold higher than the rate for a mother with anti-SSA/Ro-SSB/La antibodies who never had an affected child, supporting close echocardiographic monitoring in all subsequent pregnancies, with heightened surveillance between 18 and 24 weeks of gestation.

Acute renal failure secondary to interstitial lupus nephritis.

A patient with systemic lupus erythematosus (SLE), followed up over a six-month period, exhibited numerous immunologic abnormalities and varied renal pathologic features. Initial findings included minimal glomerular lesions, serum antibodies directed solely against nuclear RNA protein, and lupus band test showing pure IgM deposition. These findings suggested a good prognosis. Subsequently, the patient developed acute renal failure secondary to an interstitial lupus nephritis, without progression of the glomerular abnormality. Serum antibodies to the nuclear non-nucleic acid macromolecule and single stranded and native DNA were demonstrated concurrently. New skin deposits of IgG and IgA in addition to IgM also were observed. This patient demonstrates the potential progression of lupus renal disease despite the initial favorable prognostic indicators.

Dry eye and dry mouth in the elderly: a population-based assessment.

BACKGROUND: Symptoms of dry eye and dry mouth are common in the elderly and are often debilitating. Previous research on small populations has been inconsistent regarding the contribution to sicca symptoms of autoimmune markers, medication use, and other factors. The objective of this study was to determine the population prevalence of symptoms of dry eye and dry mouth and to evaluate possible risk factors. METHODS: This is a population-based study of 2481 individuals, aged 65 to 84 years, residing in Salisbury, Md, and identified by the Health Care Financing Medicare database. The main outcome measures included information on sicca symptoms, medical history, medication use, and joint examination results collected in a standardized manner. Autoimmune status was assessed in 1200 individuals by measuring antinuclear antibody, rheumatoid factor, and autoantibodies to the soluble nuclear antigens Ro/SS-A and La/SS-B by double immunodiffusion. RESULTS: Approximately 27% of the population reported dry eye or dry mouth symptoms to be present often or all the time and 4.4% reported both. The prevalence of dry mouth (but not dry eye) symptoms increased with age, female sex, and white race. No association of sicca symptoms was found with rheumatoid arthritis, smoking, alcohol consumption, reproductive hormonal status, or the presence of autoantibodies. A strong, dose-response relationship was observed between sicca symptoms and the use of certain medication classes. The proportion of the population prevalence of sicca symptoms attributable to the use of drying medications was estimated at 62% for dry eye and dry mouth and 38% for dry eye or dry mouth symptoms. CONCLUSIONS: Sicca symptoms are common in the elderly, and medication side effects appear to be a major underlying factor. Our results do not indicate an association between autoimmune status and sicca symptoms and do not support immunologic testing in persons with sicca symptoms in the absence of other important systemic features.

Subsets in systemic lupus erythematosus.

In recent years, evidence from several laboratories has indicated that various subsets of systemic lupus erythematosus exist. Some of these subsets have distinctive mucocutaneous features but more importantly they have different prevalence of renal disease--thus different prognosis. These subsets are defined by the specificity of the serum antibodies the SLE patient possesses.

Anti-Ro(SS-A) HLA-DR3-positive women: the interrelationship between some ANA negative, SS, SCLE, and NLE mothers and SS/LE overlap female patients.

During the past 15 years, the clinical spectrum associated with the anti-Ro(SS-A) antibody response has been defined. Various clinical presentations, including subacute cutaneous lupus erythematosus, the neonatal lupus syndrome, the Sjögren's syndrome/lupus erythematous overlap syndrome, and primary Sjögren's syndrome, have been detected in association with the anti-Ro(SS-A) response. The anti-Ro(SS-A) antibody response is associated with the HLA-DR2 and HLA-DR3 phenotypes. There is now a good deal of evidence to suggest that many anti-Ro(SS-A)-positive HLA-DR3 women are genetically closely related, sharing in common an enriched frequency of the HLA-DR3-linked B8, DQw2, and DRW52 phenotypes. DNA sequence studies have confirmed this genetic relationship. These studies have led us to the following conclusions. 1) The HLA-DR2 and HLA-DR3 associations with systemic lupus erythematosus and the HLA-DR3 association with Sjögren's syndrome are related to the anti-Ro(SS-A) antibody response and not to the clinical disease expression. 2) HLA-DR3 anti Ro-positive female patients with first-degree Sjögren's syndrome, subacute cutaneous lupus erythematosus, or Sjögren's syndrome, or who are asymptomatic, are immunogenetically closely related even though the clinical presentations are strikingly different. All these HLA-DR3 anti-Ro(SS-A) antibody-positive women are at risk to give birth to a child with the neonatal lupus syndrome.

Cutaneous manifestations of primary Sjögren's syndrome: a reflection of vasculitis and association with anti-Ro(SSA) antibodies.

Twenty-two symptomatic primary Sjögren's syndrome patients with clinical and histologic evidence of skin disease were studied. Purpura and urticaria were the most frequent clinical cutaneous manifestations. Most of these lesions were associated with a leukocytoclastic angiitis and, less commonly, a mononuclear (lymphocytic) vasculitis. Two main cutaneous syndromes were identified whose clinical, serologic, and histopathologic features were indistinguishable from Waldenström's benign hyperglobulinemic purpura and hypocomplementemic urticaria-like vasculitis. Eighty-four percent of primary Sjögren's syndrome patients with vasculitis demonstrated anti-Ro(SSA) antibodies. Thus, purpura and urticaria may reflect cutaneous vasculitis occurring in the clinical setting of Sjögren's syndrome.

Lupus band test in untreated SLE patients: correlation of immunoglobulin deposition in the skin of the extensor forearm with clinical renal disease and serological abnormalities.

This study demonstrated that 88% of untreated systemic lupus erythematosus patients with clinical renal disease displayed the deposition of immunoglobulin and complement at the dermal epidermal junction of the noninvolved light exposed extensor surface of the upper 1/3 of the forearm (P less than 0.005) (positive lupus band test). Eighty-five percent of these untreated systemic lupus erythematosus patients with anti-deoxyribonucleic acid antibodies (native and/or single stranded) (P less than 0.001) and 96% of systemic lupus erythematosus patients with hypocomplementemia had a positive lupus band test (P less than 0.001). Those systemic lupus erythematosus patients with a negative lupus band test or a positive lupus band test composed of pure IgM had a decreased incidence of renal disease, serum hypocomplementemia and anti-DNA antibodies. Their sera, however, frequently contained antibodies directed against nuclear ribonuclear protein or against the cytoplasmic non-nucleic acid glycoprotein termed Ro. On the contrary, 85% of systemic lupus erythematosus patients with a positive lupus band test composed solely or in part of IgG, had anti-DNA antibodies (P less than 0.001). Their sera also frequently contained anti-Sm antibodies. The lupus band test was found to be dynamic. In general, the appearance as well as the disappearance or the marked decrease in intensity and complexity of a positive lupus band test was found to correlate with disease exacerbation, remission and the appearance and disappearance of DNA antibodies and serum hypocomplementemia.

Circulating immune complexes of IgA type in dermatitis herpetiformis.

There is some evidence that dermatitis herpetiformis may be mediated by circulating immune complexes. This study attempts to define the antibody class of these complexes. All patients studied demonstrated granular deposition of IgA in the papillary dermis on direct immunofluorescence. Serum immune complexes were detected using the qualitative Raji cell immunofluorescent assay, as well as the quantitative immunoradiometric assay. A group of 25 dermatitis herpetiformis patients was found to have higher levels of IgA containing complexes compared to a group of normals (p < .01). Higher levels of IgG containing complexes were also noted in dermatitis herpetiformis patients at a low level of statistical significance (p < .1). The relationship of these complexes to the pathogenesis of dermatitis herpetiformis is yet to be determined.

Nucleoprotein autoantibodies in lupus erythematosus.

Autoantibodies against deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) proteins are commonly detected in patients with lupus erythematosus (LE). Antibodies against native DNA are frequently detected in a subset of LE patients with a high prevalence of renal disease. Single-stranded DNA antibodies are also commonly detected in patients with systemic lupus erythematosus (SLE) but recent evidence indicates that approximately 25% of patients with benign, cutaneous (discoid) lupus also possess single-stranded DNA IgM autoantibodies. LE patients also frequently possess antibodies directed against a variety of ribonuclear proteins (RNP). These RNA protein autoantibodies are generally divided into two groups. One group is termed snRNPs (small nuclear ribonuclear protein); the other is termed scRNPs (small cytoplasmic ribonuclear protein). Anti-RNA protein autoantibodies occur as frequently in patients with SLE as do native DNA antibodies. Furthermore, in contradistinction to nDNA antibodies, lupus patients generally make large quantities (detected by gel precipitin techniques) of anti-RNP antibodies. The anti-RNP antibodies are directed against proteins that bind with specific RNA nucleotides. The best evidence at present indicates that these RNA proteins containing the specific RNA nucleotides are involved in RNA processing and post-translational activities such as protein synthesis. Furthermore, these SLE autoantibodies are now being employed, together with other autoantibody systems detected in other connective tissue diseases, to define the biological role of the respective RNA proteins.

Neonatal lupus erythematosus: new serologic findings.

A child with neonatal lupus was evaluated and found to possess serum anti Ro(SSA) antibodies. The cutaneous lesions and anti Ro(SSA) antibodies disappeared during the next 5 mo. The infant's mother was asymptomatic but possessed anti Ro(SSA) and anti La(SSB) antibodies.

Unusual cutaneous manifestations of systemic lupus erythematosus: I. Urticaria-like lesions. Correlation with clinical and serological abnormalities.

Ten of 143 systemic lupus erythematosus patients demonstrated urticaria-like lesions. Lesional biopsies in 7 of 9 patients tested revealed a leukocytoclastic angiitis and in 2, a mononuclear perivascular infiltrate. Direct immunofluorescent studies in 2 of 6 patients tested revealed IgM and C3 deposition in and about dermal blood vessels. Nine of the 10 systemic lupus erythematosus, patients displayed active clinical disease (e.g., arthritis, renal disease, etc.), a positive lupus band test, antibodies against deoxyribonucleic acid or Sm macromolecules, serum hypocomplementemia and markedly elevated quantities of serum immune complexes as determined by an immunoradiometric assay employing Raji cells. Similar lesions were not detected in 35 discoid lupus erythematosus patients. These studies strongly suggest: (1) urticaria-like lesions are uncommon cutaneous manifestations of systemic lupus erythematosus. (2) These urticaria-like lesions do not represent a classic IgE mediated urticaria. (3) These urticaria-like lesions generally occur in lupus erythematosus patients demonstrating clinical and/or serological evidence of systemic disease activity. (4) These lesions are probably secondary to immune complex deposition. We, therefore, conclude that all urticarial lesions in lupus erythematosus patients should be biopsied and the patient evaluated for active systemic disease.

Ro(SS-A) positive Sjogren's/lupus erythematosus (SC/LE) overlap patients are associated with the HLA-DR3 and/or DRw6 phenotypes.

Ro(SS-A) positive female Sjögren's syndrome (SS) lupus erythematosus (LE) overlap patients are a clinically and serologically homogeneous group generally demonstrating prominent subacute cutaneous lupus erythematosus (SCLE) lesions, cutaneous vasculitis, peripheral and central nervous system disease, pulmonary disease, and a low frequency of glomerulonephritis. They commonly demonstrate rheumatoid factor, hypergammaglobulinemia, antinuclear and Ro(SS-A) La(SS-B) antibody activity. This study indicates that these patients are also immunogenetically similar, sharing a statistically significant increased frequency of HLA-B8, DR3, DRW6, DQ2, and DRw52. Sixty-three percent of these SS/LE patients possess the extended haplotype (P-value 6.0 X 10(-3); RR 9.5) HLA-B8, DR3, DQ2, DRw52. One hundred percent of this SS/LE cohort was DR3 or DRw6 (P-value less than or equal to 5.0 X 10(-3); relative risk 19.1). Fifty percent of these patients were HLA DR3/DRw6 heterozygotes (P-value 1.5 X 10(-6); relative risk 31.2). Thus, HLA-DR3 and DRw6 Ro(SS-A) positive SS/LE patients may possess a similar, if not unique, DR region DNA nucleotide sequence involved in disease susceptibility or immune regulation.

A sensitive and specific assay to detect Ro(SS-A) and La(SS-B) antibodies.

This paper describes a sensitive and specific immunoblotting procedure to detect Ro(SS-A) and La(SS-B) autoantibodies in the serum of patients with lupus erythematosus. In order to perform this procedure, we have partially purified the Ro(SS-A) and La(SS-B) antigens from human spleen extracts by DEAE-cellulose and Sephacryl S-300 chromatography. The Ro(SS-A) and La(SS-B) antigens were immobilized on nitrocellulose paper after sodium dodecyl sulfate-polyacrylamide gel electrophoresis and tested against a panel of sera at different dilutions: normal human sera (n = 14), Ro(SS-A) antisera (n = 6), La(SS-B) (n = 7), Ro(SS-A)/La(SS-B) (n = 8), Sm-nRNP-La(SS-B) (n = 2). We found that Ro(SS-A) antisera react with a protein of an approximate Mr of 58K, whereas the La(SS-B) antisera reacted with two bands of Mr 42 and 40K, respectively. Antisera with both autoantibodies [Ro(SS-A) and La(SS-B)] reacted with both antigens, whereas the control NHS, anti-nRNP, and anti-Sm did not stain the Ro(SS-A) and La(SS-B) protein bands. In addition, some of the positive sera continued reacting with the respective antigens at extremely high dilutions. This procedure can be easily adapted to test many serum samples and produce data which include Mr of the antigen and titer of autoantibodies in the patient's serum.

The immunogenetic relationship between anti-Ro(SS-A)/La(SS-B) antibody positive Sjögren's/lupus erythematosus overlap syndrome and the neonatal lupus syndrome.

We have described previously the clinical features of a unique group of anti-Ro(SS-A) antibody positive Sjogren's patients who have cutaneous features of lupus erythematosus, most commonly subacute cutaneous lupus erythematosus, defined as the Sjogren's/lupus erythematosus overlap syndrome. Three of these patients are also mothers of infants with the neonatal lupus erythematosus syndrome, characterized by cutaneous lesions resembling subacute cutaneous lupus erythematosus or congenital heart block. Patients with Sjogren's/lupus erythematosus overlap syndrome, subacute cutaneous lupus erythematosus, and mothers of infants with the neonatal lupus syndrome characteristically have autoantibodies to Ro(SS-A), and in many cases, La(SS-B) antigens. The present study was designed to test the hypothesis that anti-Ro(SS-A)/La(SS-B) positive Sjogren's/lupus overlap patients and mothers of infants with neonatal lupus erythematosus syndrome are immunogenetically homogenous and closely related. We report a strong association with HLA-B8, DR3, DQw2, and DRw52 phenotypes and the HLA-B8, DR3, DQw2, DRw52 extended haplotype in both patient cohorts. Furthermore, we describe disease associations with HLA-DR3/DRw6 heterozygotes in both patient groups. These data demonstrate that anti-Ro(SS-A)/La(SS-B) positive Sjogren's/lupus overlap patients and neonatal lupus syndrome mothers are immunogenetically closely related to each other and appear to be more closely related to both primary Sjogren's syndrome and subacute lupus erythematosus, than to classical systemic lupus erythematosus.

Epidermolysis bullosa acquisita: ultrastructural and immunological studies.

Four patients with epidermolysis bullosa acquisita were investigated using immunofluorescence, routine electron microscopic and immunoelectron microscopic techniques. Immunofluorescence studies demonstrated linear immunoglobulin and complement deposition along the dermal-epidermal junction. These findings are similar to those seen in skin of patients with bullous pemphigoid. Immunoelectron microscopic studies demonstrated that the immunoreactants were localized below the subbasal lamina-anchoring fibril zone of the basement membrane, thereby clearly distinguishing the immunopathology of epidermolysis bullosa acquisita from that seen in bullous pemphigoid. Indirect immunoelectron microscopic findings suggest that epidermal basal cells of affected patients may secrete the dermal substances to which the antibodies bind.