Aberrantly low STAT3 and STAT5 responses are associated with poor outcome and an inflammatory gene expression signature in pediatric acute myeloid leukemia

The relapse rate for children with acute myeloid leukemia is nearly 40% despite aggressive chemotherapy and often stem cell transplant. We sought to understand how environment-induced signaling responses are associated with clinical response to treatment. We previously reported that patients whose AML cells showed low G-CSF-induced STAT3 activation had inferior event-free survival compared to patients with stronger STAT3 responses. Here, we expanded the paradigm to evaluate multiple signaling parameters induced by a more physiological stimulus. We measured STAT3, STAT5 and ERK1/2 responses to G-CSF and to stromal cell-conditioned medium for 113 patients enrolled on COG trials AAML03P1 and AAML0531. Low inducible STAT3 activity was independently associated with inferior event-free survival in multivariate analyses. For inducible STAT5 activity, those with the lowest and highest responses had inferior event-free survival, compared to patients with intermediate STAT5 responses. Using existing RNA-sequencing data, we compared gene expression profiles for patients with low inducible STAT3/5 activation with those for patients with higher inducible STAT3/5 signaling. Genes encoding hematopoietic factors and mitochondrial respiratory chain subunits were overexpressed in the low STAT3/5 response groups, implicating inflammatory and metabolic pathways as potential mechanisms of chemotherapy resistance. We validated the prognostic relevance of individual genes from the low STAT3/5 response signature in a large independent cohort of pediatric AML patients. These findings provide novel insights into interactions between AML cells and the microenvironment that are associated with treatment failure and could be targeted for therapeutic interventions (AU)

Aberrantly low STAT3 and STAT5 responses are associated with poor outcome and an inflammatory gene expression signature in pediatric acute myeloid leukemia.

The relapse rate for children with acute myeloid leukemia is nearly 40% despite aggressive chemotherapy and often stem cell transplant. We sought to understand how environment-induced signaling responses are associated with clinical response to treatment. We previously reported that patients whose AML cells showed low G-CSF-induced STAT3 activation had inferior event-free survival compared to patients with stronger STAT3 responses. Here, we expanded the paradigm to evaluate multiple signaling parameters induced by a more physiological stimulus. We measured STAT3, STAT5 and ERK1/2 responses to G-CSF and to stromal cell-conditioned medium for 113 patients enrolled on COG trials AAML03P1 and AAML0531. Low inducible STAT3 activity was independently associated with inferior event-free survival in multivariate analyses. For inducible STAT5 activity, those with the lowest and highest responses had inferior event-free survival, compared to patients with intermediate STAT5 responses. Using existing RNA-sequencing data, we compared gene expression profiles for patients with low inducible STAT3/5 activation with those for patients with higher inducible STAT3/5 signaling. Genes encoding hematopoietic factors and mitochondrial respiratory chain subunits were overexpressed in the low STAT3/5 response groups, implicating inflammatory and metabolic pathways as potential mechanisms of chemotherapy resistance. We validated the prognostic relevance of individual genes from the low STAT3/5 response signature in a large independent cohort of pediatric AML patients. These findings provide novel insights into interactions between AML cells and the microenvironment that are associated with treatment failure and could be targeted for therapeutic interventions.

Switch from BAK-preserved to preservative-free latanoprost decreases anterior chamber flare in POAG patients.

PURPOSE: To validate the hypothesis that BAK induces low-grade inflammation in the anterior chamber, we designed a study to investigate whether switching from BAK-preserved to preservative-free latanoprost in patients with primary open-angle glaucoma (POAG) would reduce the flare levels. PATIENTS: Forty-one eyes of twenty-two patients with primary open-angle glaucoma treated with BAK-preserved latanoprost for at least 6 months as monotherapy were included. Exclusion criteria included any use of topical eye drops other than latanoprost, pseudoexfoliation and pigment dispersion glaucoma, wearing of contact lenses and intraocular surgery in the past year. METHODS: At the start of the study, we measured baseline flare values. We then switched all patients to preservative-free latanoprost. After 1, 2, and 3 months, a routine ophthalmological examination was performed and flare measurement repeated. RESULTS: Thirty-three eyes were followed up throughout the entire 3-month period. One month after the switch to preservative-free latanoprost, a statistically significant mean drop in flare of - 0.96 ph/ms (P = 0.025) was observed. Mean flare decreased further by - 1.31 ph/ms (P = 0.0027) after 2 months and by - 1.25 ph/ms (P = 0.0041) after 3 months. CONCLUSION: The switch from BAK-preserved to preservative-free latanoprost induced a statistically significant reduction in mean flare value. Whereas our previous study showed an increase in flare when initiating treatment with BAK-preserved eye drops, this study shows a decrease in flare upon cessation of BAK-preserved drugs. The combined evidence from the two studies strongly suggests that in humans BAK exerts its effects not only on the ocular surface, but also at the level of the anterior chamber.

The photocycle of orange carotenoid protein conceals distinct intermediates and asynchronous changes in the carotenoid and protein components.

The 35-kDa Orange Carotenoid Protein (OCP) is responsible for photoprotection in cyanobacteria. It acts as a light intensity sensor and efficient quencher of phycobilisome excitation. Photoactivation triggers large-scale conformational rearrangements to convert OCP from the orange OCPO state to the red active signaling state, OCPR, as demonstrated by various structural methods. Such rearrangements imply a complete, yet reversible separation of structural domains and translocation of the carotenoid. Recently, dynamic crystallography of OCPO suggested the existence of photocycle intermediates with small-scale rearrangements that may trigger further transitions. In this study, we took advantage of single 7 ns laser pulses to study carotenoid absorption transients in OCP on the time-scale from 100 ns to 10 s, which allowed us to detect a red intermediate state preceding the red signaling state, OCPR. In addition, time-resolved fluorescence spectroscopy and the assignment of carotenoid-induced quenching of different tryptophan residues derived thereof revealed a novel orange intermediate state, which appears during the relaxation of photoactivated OCPR to OCPO. Our results show asynchronous changes between the carotenoid- and protein-associated kinetic components in a refined mechanistic model of the OCP photocycle, but also introduce new kinetic signatures for future studies of OCP photoactivity and photoprotection.

Genetic association of CD247 (CD3ζ) with SLE in a large-scale multiethnic study.

A classic T-cell phenotype in systemic lupus erythematosus (SLE) is the downregulation and replacement of the CD3ζ chain that alters T-cell receptor signaling. However, genetic associations with SLE in the human CD247 locus that encodes CD3ζ are not well established and require replication in independent cohorts. Our aim was therefore to examine, localize and validate CD247-SLE association in a large multiethnic population. We typed 44 contiguous CD247 single-nucleotide polymorphisms (SNPs) in 8922 SLE patients and 8077 controls from four ethnically distinct populations. The strongest associations were found in the Asian population (11 SNPs in intron 1, 4.99 × 10(-4) < P < 4.15 × 10(-2)), where we further identified a five-marker haplotype (rs12141731-rs2949655-rs16859085-rs12144621-rs858554; G-G-A-G-A; P(hap) = 2.12 × 10(-5)) that exceeded the most associated single SNP rs858554 (minor allele frequency in controls = 13%; P = 4.99 × 10(-4), odds ratio = 1.32) in significance. Imputation and subsequent association analysis showed evidence of association (P < 0.05) at 27 additional SNPs within intron 1. Cross-ethnic meta-analysis, assuming an additive genetic model adjusted for population proportions, showed five SNPs with significant P-values (1.40 × 10(-3) < P< 3.97 × 10(-2)), with one (rs704848) remaining significant after Bonferroni correction (P(meta) = 2.66 × 10(-2)). Our study independently confirms and extends the association of SLE with CD247, which is shared by various autoimmune disorders and supports a common T-cell-mediated mechanism.

Assessing and ensuring patient safety during breath-holding for radiotherapy.

OBJECTIVE: While there is recent interest in using repeated deep inspiratory breath-holds, or prolonged single breath-holds, to improve radiotherapy delivery, breath-holding has risks. There are no published guidelines for monitoring patient safety, and there is little clinical awareness of the pronounced blood pressure rise and the potential for gradual asphyxia that occur during breath-holding. We describe the blood pressure rise during deep inspiratory breath-holding with air and test whether it can be abolished simply by pre-oxygenation and hypocapnia. METHODS: We measured blood pressure, oxygen saturation (SpO2) and heart rate in 12 healthy, untrained subjects performing breath-holds. RESULTS: Even for deep inspiratory breath-holds with air, the blood pressure rose progressively (e.g. mean systolic pressure rose from 133 ± 5 to 175 ± 8 mmHg at breakpoint, p < 0.005, and in two subjects, it reached 200 mmHg). Pre-oxygenation and hypocapnia prolonged breath-hold duration and prevented the development of asphyxia but failed to abolish the pressure rise. The pressure rise was not a function of breath-hold duration and was not signalled by any fall in heart rate (remaining at resting levels of 72 ± 2 beats per minute). CONCLUSION: Colleagues should be aware of the progressive blood pressure rise during deep inspiratory breath-holding that so far is not easily prevented. In breast cancer patients scheduled for breath-holds, we recommend routine screening for heart, cardiovascular, renal and cerebrovascular disease, routine monitoring of patient blood pressure and SpO2 during breath-holding and requesting patients to stop if systolic pressure rises consistently >180 mmHg and or SpO2 falls <94%. ADVANCES IN KNOWLEDGE: There is recent interest in using deep inspiratory breath-holds, or prolonged single breath-holding techniques, to improve radiotherapy delivery. But there appears to be no clinical awareness of the risks to patients from breath-holding. We demonstrate the progressive blood pressure rise during deep inspiratory breath-holds with air, which we show cannot be prevented by the simple expedient of pre-oxygenation and hypocapnia. We propose patient screening and safety guidelines for monitoring both blood pressure and SpO2 during breath-holds and discuss their clinical implications.

Independent contribution of bronchoalveolar lavage and serum galactomannan in the diagnosis of invasive pulmonary aspergillosis.

The optimal combination of galactomannan index (GMI) testing for the diagnosis of invasive pulmonary aspergillosis (IPA) remains unclear. For diagnostic approaches that are triggered by clinical signs and symptoms in high-risk patients, institutional variation remains, with some centers routinely relying on only serum GMI or bronchoalveolar lavage (BAL) GMI testing. In addition, use of mold-active agents before diagnosis of IPA is becoming increasingly common, and understanding the effect of these drugs on test yield is important when making time-critical treatment decisions. In a single-center cohort of 210 allogeneic hematopoietic cell transplant recipients, we found that serum and BAL GMI testing contributed independently to IPA diagnosis, supporting the practice of sending both tests simultaneously to ensure a timely diagnosis of IPA. BAL GMI sensitivity was not affected by receipt of mold-active therapy in our cohort.

Breast cancer risk following Hodgkin lymphoma radiotherapy in relation to menstrual and reproductive factors.

BACKGROUND: Women treated with supradiaphragmatic radiotherapy (sRT) for Hodgkin lymphoma (HL) at young ages have a substantially increased breast cancer risk. Little is known about how menarcheal and reproductive factors modify this risk. METHODS: We examined the effects of menarcheal age, pregnancy, and menopausal age on breast cancer risk following sRT in case-control data from questionnaires completed by 2497 women from a cohort of 5002 treated with sRT for HL at ages <36 during 1956-2003. RESULTS: Two-hundred and sixty women had been diagnosed with breast cancer. Breast cancer risk was significantly increased in patients treated within 6 months of menarche (odds ratio (OR) 5.52, 95% confidence interval (CI) (1.97-15.46)), and increased significantly with proximity of sRT to menarche (Ptrend<0.001). It was greatest when sRT was close to a late menarche, but based on small numbers and needing reexamination elsewhere. Risk was not significantly affected by full-term pregnancies before or after treatment. Risk was significantly reduced by early menopause (OR 0.55, 95% CI (0.35-0.85)), and increased with number of premenopausal years after treatment (Ptrend=0.003). CONCLUSION: In summary, this paper shows for the first time that sRT close to menarche substantially increases breast cancer risk. Careful consideration should be given to follow-up of these women, and to measures that might reduce their future breast cancer risk.

A functional haplotype of UBE2L3 confers risk for systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disease with diverse clinical manifestations characterized by the development of pathogenic autoantibodies manifesting in inflammation of target organs such as the kidneys, skin and joints. Genome-wide association studies have identified genetic variants in the UBE2L3 region that are associated with SLE in subjects of European and Asian ancestry. UBE2L3 encodes an ubiquitin-conjugating enzyme, UBCH7, involved in cell proliferation and immune function. In this study, we sought to further characterize the genetic association in the region of UBE2L3 and use molecular methods to determine the functional effect of the risk haplotype. We identified significant associations between variants in the region of UBE2L3 and SLE in individuals of European and Asian ancestry that exceeded a Bonferroni-corrected threshold (P<1 × 10(-4)). A single risk haplotype was observed in all associated populations. Individuals harboring the risk haplotype display a significant increase in both UBE2L3 mRNA expression (P=0.0004) and UBCH7 protein expression (P=0.0068). The results suggest that variants carried on the SLE-associated UBE2L3 risk haplotype influence autoimmunity by modulating UBCH7 expression.

Role of MYH9 and APOL1 in African and non-African populations with lupus nephritis.

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by autoantibody production and organ damage. Lupus nephritis (LN) is one of the most severe manifestations of SLE. Multiple studies reported associations between renal diseases and variants in the non-muscle myosin heavy chain 9 (MYH9) and the neighboring apolipoprotein L 1 (APOL1) genes. We evaluated 167 variants spanning MYH9 for association with LN in a multiethnic sample. The two previously identified risk variants in APOL1 were also tested for association with LN in European-Americans (EAs) (N = 579) and African-Americans (AAs) (N = 407). Multiple peaks of association exceeding a Bonferroni corrected P-value of P < 2.03 × 10(-3) were observed between LN and MYH9 in EAs (N = 4620), with the most pronounced association at rs2157257 (P = 4.7 × 10(-4), odds ratio (OR) = 1.205). A modest effect with MYH9 was also detected in Gullah (rs8136069, P = 0.0019, OR = 2.304). No association between LN and MYH9 was found in AAs, Asians, Amerindians or Hispanics. This study provides the first investigation of MYH9 in LN in non-Africans and of APOL1 in LN in any population, and presents novel insight into the potential role of MYH9 in LN in EAs.

Evaluation of the TREX1 gene in a large multi-ancestral lupus cohort.

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disorder with a complex pathogenesis in which genetic, hormonal and environmental factors have a role. Rare mutations in the TREX1 gene, the major mammalian 3'-5' exonuclease, have been reported in sporadic SLE cases. Some of these mutations have also been identified in a rare pediatric neurological condition featuring an inflammatory encephalopathy known as Aicardi-Goutières syndrome (AGS). We sought to investigate the frequency of these mutations in a large multi-ancestral cohort of SLE cases and controls. A total of 40 single-nucleotide polymorphisms (SNPs), including both common and rare variants, across the TREX1 gene, were evaluated in ∼8370 patients with SLE and ∼7490 control subjects. Stringent quality control procedures were applied, and principal components and admixture proportions were calculated to identify outliers for removal from analysis. Population-based case-control association analyses were performed. P-values, false-discovery rate q values, and odds ratios (OR) with 95% confidence intervals (CI) were calculated. The estimated frequency of TREX1 mutations in our lupus cohort was 0.5%. Five heterozygous mutations were detected at the Y305C polymorphism in European lupus cases but none were observed in European controls. Five African cases incurred heterozygous mutations at the E266G polymorphism and, again, none were observed in the African controls. A rare homozygous R114H mutation was identified in one Asian SLE patient, whereas all genotypes at this mutation in previous reports for SLE were heterozygous. Analysis of common TREX1 SNPs (minor allele frequency (MAF)>10%) revealed a relatively common risk haplotype in European SLE patients with neurological manifestations, especially seizures, with a frequency of 58% in lupus cases compared with 45% in normal controls (P=0.0008, OR=1.73, 95% CI=1.25-2.39). Finally, the presence or absence of specific autoantibodies in certain populations produced significant genetic associations. For example, a strong association with anti-nRNP was observed in the European cohort at a coding synonymous variant rs56203834 (P=2.99E-13, OR=5.2, 95% CI=3.18-8.56). Our data confirm and expand previous reports and provide additional support for the involvement of TREX1 in lupus pathogenesis.

Active systemic lupus erythematosus is associated with failure of antigen-presenting cells to express programmed death ligand-1.

OBJECTIVE: Antigen-presenting cells (APC) play critical roles in establishing and maintaining peripheral tolerance. This is accomplished in part via expression of negative co-stimulatory molecules such as programmed death ligand-1 (PD-L1) on tolerogenic APC, such as immature myeloid dendritic cells (mDC). Several studies have strongly linked dysfunction of APC, including mDC, to the pathogenesis of SLE. The objective of this study was to determine whether APC expressed PD-L1 protein at normal levels during active lupus. METHODS: Peripheral blood mononuclear cells (PBMC) were isolated from 19 paediatric patients with SLE and from 17 healthy age-matched controls. PBMC from both cohorts were cultured in the absence of exogenously added stimuli, and leucocyte PD-L1 expression was measured by flow cytometry. RESULTS: Immature mDC and monocytes (Mo) from healthy children expressed little PD-L1 at initial isolation, but spontaneously up-regulated PD-L1 by 24 h. In contrast, both mDC and Mo from patients with active SLE failed to up-regulate PD-L1 over a 5 day time course, expressing this protein only during disease remissions. CONCLUSIONS: These data are the first to link active lupus with reversibly decreased PD-L1 expression on professional APC, suggesting a novel mechanism for loss of peripheral tolerance in SLE.

The changing maternal "self" hypothesis: a mechanism for maternal tolerance of the fetus.

Recent advances in placental biology and immunology lead us to propose a novel hypothesis for maternal tolerance of the semi-allogeneic fetus and amelioration of rheumatoid arthritis (RA) during pregnancy. The initial event in this hypothesis is extrusion of placental apoptotic syncytiotrophoblast debris recently identified to contain intracellular fetal HLA Class II molecules, into maternal blood. The second event is uptake of apoptotic syncytiotrophoblast by immature maternal dendritic cells and presentation of fetal HLA class II peptides. In addition to presenting foreign antigens, HLA molecules also present HLA self-peptides. In the setting of the non-inflammatory environment of pregnancy, this process is expected to induce peripheral tolerance of fetal antigens through T cell death, anergy or induction of regulatory T cells in the lymph nodes. This hypothesis suggests a mechanism by which the simultaneous presentation of fetal and self (RA-associated) HLA peptides by tolerogenic dendritic cells during pregnancy may explain the observed amelioration of RA as a secondary benefit of fetal tolerance. After delivery, apoptotic syncytiotrophoblast debris disappears from maternal blood, autoimmunity returns and RA recurs. Thus, during pregnancy maternal immunologic "self" includes fetal HLA Class II as a result of apoptotic syncytiotrophoblast uptake by maternal tolerogenic dendritic cells.

LPS induces translocation of TLR4 in amniotic epithelium.

Toll-like receptor 4 (TLR4) mediates lipopolysaccharide (LPS) induced immune responses, which may contribute to preterm labor associated with intraamniotic gram-negative bacterial infections. The study objective was to investigate gestational age and LPS-induced changes in TLR4 subcellular localization within amniotic epithelium, the first line of host defense against intraamniotic bacteria. TLR4 localization in amniotic epithelium was assessed using immunohistochemistry on 24 placentas of different gestational ages: first trimester (n=6), second trimester (n=6), and third trimester (n=12). Immunofluorescence was used to determine TLR4 localization following ex vivo LPS stimulation of amnion from women undergoing cesarean section without labor at term. TLR4 was expressed in the cytoplasm of amniotic epithelium starting at 9weeks with apical polarization by 25weeks gestation. TLR4 localization to the basal membrane was significantly associated with chorioamnionitis (p=0.01). After LPS stimulation, TLR4 was expressed sequentially within the apical membrane, cytoplasm, and finally in the basal cellular compartment. This suggests that TLR4 expression in amniotic epithelium is poised to monitor amniotic fluid for pathogens. TLR4 translocation to the basal membrane may decrease LPS signaling early in an infection, but allow the amniotic epithelium to remain competent to invasive or intracellular bacteria.

Two cases of acute macular neuroretinopathy.

PURPOSE: To report chorioretinal vasoconstriction as a potential pathogenic mechanism in acute macular neuroretinopathy (AMNR). To describe a time lag between the onset of functional deficits and that of fundoscopically visible lesions and illustrate the superior value of infrared (IR) compared to red-free or white light imaging in AMNR. METHODS: Two young female patients (30 and 19 years old) with AMNR are described. Both underwent detailed clinical examination with additional imaging using IR, blue, and red-free light. Functional evaluation with pattern and multifocal electroretinography, Goldmann manual, and automated Humphrey visual fields (VFs) was also performed. RESULTS: The first patient was diagnosed with AMNR after a caesarian section during and after which she received treatment with vasoconstrictive drugs. She was followed up for 28 months, after which time she still suffered from bilateral U-shaped paracentral scotomata associated with macular lesions. The second patient complained of central scotomata prior to the onset of any visible fundoscopic lesions, following a bout of flu. VFs confirmed a central scotoma and pattern electroretinography was consistent with loss of macular function. Bilateral petaloid lesions became visible after 3 days when function began to improve. In both patients IR imaging was superior to standard red-free and white light in identifying macular lesions. CONCLUSIONS: Vasoconstriction in the chorioretina may be pathogenic in AMNR. Functional complaints precede fundus lesions in AMNR. And, IR light is superior to red-free or white light imaging in detecting typical fundus lesions in AMNR both early and late in the course of the disease.

Microchimeric cells in systemic lupus erythematosus: targets or innocent bystanders?

During pregnancy maternal and fetal cells commute back and forth leading to fetal microchimerism in the mother and maternal microchimerism in the child that can persist for years after the birth. Chimeric fetal and maternal cells can be hematopoietic or can differentiate into somatic cells in multiple organs, potentially acting as targets for 'autoimmunity' and so have been implicated in the pathogenesis of autoimmune diseases that resemble graft-versus-host disease after stem cell transplantation. Fetal cells have been found in women with systemic lupus erythematosus, both in the blood and a target organ, the kidney, suggesting that they may be involved in pathogenesis. Future studies will address how the host immune system normally tolerates maternal and fetal cells or how the balance may change during autoimmunity.

Experience in the use of the palliative care outcome scale.

GOALS OF WORK: The objective of the study is to assess the Palliative Care Outcome Scale (POS) as a potential audit tool within a specialist cancer centre. It also aims to answer the following questions: does the tool identify problem areas and demonstrate changes in quality of life over time? How well do staff and patient ratings correlate? PATIENTS AND METHODS: The POS questionnaire was piloted at a specialist cancer centre. Thirty consecutive patients admitted to the palliative care wards and ward staff completed questionnaires on admission and twice weekly until discharge or death. A further questionnaire assessed staff attitudes. RESULTS: There was a significant improvement in overall patient POS score at 1 week (days 5-9). Four "symptoms" or issues were scored as being important for our patients: pain, other symptoms, anxiety and patient's perception of family anxiety. These all significantly improved within the first week. At the initial assessment, staff underestimated patients' pain and overestimated problems relating to information giving and patients' ability to share their feelings. There was no significant difference between staff and patient scores after 1 week. The other six areas covered by the tool were less important; this may reflect the patient population seen at our centre. Use of the tool identified areas for staff training and effectively demonstrated improvement in patient care. CONCLUSION: The POS is an outcome measure tool designed to assess physical, psychological, practical and existential aspects of quality of life. It may be useful in identifying problems in individual patients and directing care to address these needs.

Human leukocyte antigen class II alleles in Caucasian women with primary biliary cirrhosis.

In the current study, we investigated human leukocyte antigen (HLA) class II alleles in Caucasian women with primary biliary cirrhosis (PBC), a disease that preferentially affects women. Alleles of DRB1, DQA1, and DQB1 were determined by DNA-based HLA typing for women with PBC (n = 72) and healthy women (n = 381). All study subjects were Caucasian. HLA DRB1*08 was significantly increased in women with PBC compared to healthy women. The increase was primarily due to the DRB1*0801 allele, also the most common DRB1*08 allele among controls. DQB1*04 and DQA1*0401 were significantly increased. DRB1*1501, DQA1*0102, and DQB1*0602 were associated with decreased risk. Analyses conducted comparing parous women with PBC to parous healthy women (n = 68 and n = 282, respectively) yielded similar significant results. Although the DRB1*08-DQA1*0401-DQB1*04 haplotype was significantly associated with PBC, consistent with other studies, this haplotype nevertheless represented only 19% (14/72) of all PBC patients and can account for only a minority of the risk of PBC.

Maternal and sibling microchimerism in twins and triplets discordant for neonatal lupus syndrome-congenital heart block.

OBJECTIVE: Neonatal lupus syndrome-congenital heart block (NLS-CHB) is an acquired autoimmune disease in which maternal autoantibodies are necessary but not sufficient for disease. Maternal myocardial cells have been found in the hearts of patients with NLS-CHB, suggesting that maternal microchimerism may also play a role. In this study we asked whether levels of microchimerism in the blood are associated with NLS-CHB in discordant twins and triplets. METHODS: Human leucocyte antigen (HLA)-specific and Y-chromosome-specific real-time quantitative polymerase chain reaction (PCR) was used to quantitatively assay maternal and sibling microchimerism in peripheral blood. Because of HLA allele sharing in families, it was not always possible to distinguish between multiple sources of microchimerism. RESULTS: In one family, maternal and/or sibling microchimerism was detected in two triplets who had CHB, but not in the triplet with transient hepatitis. Levels ranged from 4 to 948 genome-equivalents of foreign deoxyribonucleic acid per million host genome-equivalents (gEq/million). Over the first year levels of sibling microchimerism decreased in the triplet with complete CHB and increased in the triplet who progressed from first- to second-degree CHB. In a second family, maternal and/or sibling microchimerism was detected in the healthy twin (1223 gEq/million) but not in the twin with CHB. CONCLUSIONS: Maternal and/or sibling microchimerism was detectable in the blood of infant twins and triplets discordant for NLS. Microchimerism in the blood was not specific for NLS-CHB, although in one family levels correlated with disease. Thus, microchimerism in the blood and/or tissues may be involved in the pathogenesis or progression of NLS-CHB, but additional factors must also contribute. Further investigation is warranted.