OP0233 EFFICACY, SAFETY, AND PHARMACODYNAMIC EFFECTS OF THE BRUTON’S TYROSINE KINASE INHIBITOR, FENEBRUTINIB (GDC-0853), IN MODERATE TO SEVERE SYSTEMIC LUPUS ERYTHEMATOSUS IN A PHASE 2 CONTROLLED STUDY

Background:

Fenebrutinib (GDC-0853, FEN) is an oral, non-covalent, and selective inhibitor of Bruton’s tyrosine kinase (BTK) in clinical development for autoimmune diseases.

Objectives:

This was a randomized, placebo-controlled, multi-center study to evaluate the efficacy, safety, and pharmacodynamic effects of FEN in patients with moderate-to-severe systemic lupus erythematosus (SLE) activity.

Methods:

Patients who met SLICC or revised ACR SLE criteria, had ≥1 serologic marker of SLE, SLEDAI ≥8, and were on ≥1 standard of care (SOC) therapy were included; patients with renal or CNS involvement, or exposure to B cell depleting or calcineurin inhibitor therapy were excluded. Patients were randomized to placebo (PBO), FEN 150 mg QD, or FEN 200 mg BID, for 48 weeks. A corticosteroid taper was recommended, with burst and taper permitted from Week 0 (W0) to W12 and W24 to W36. The primary endpoint was SRI-4 at W48. Post hoc subgroup analyses were conducted based on patient baseline disease characteristics.

Results:

This study enrolled 260 patients, with the majority recruited in Latin America, USA, and Western Europe. At W48, the SRI-4 response rates for FEN 150 mg QD and FEN 200 mg BID were 51% (95% CI: -8.5, 21.2; p value 0.37) and 52% (95% CI: -7.3, 22.4; p value 0.34), respectively, compared to 44% for PBO (Table 1). Post-hoc analysis showed larger responses in subgroups of patients with higher baseline disease activity (Table 1). Safety results were similar between FEN and PBO arms, although more serious adverse events were observed in the FEN 200 mg BID arm. Study discontinuations were balanced across the 3 arms (24-26%). FEN treatment significantly reduced levels of CD19+ B cells, anti-dsDNA autoantibodies, IgG, and a BTK-dependent RNA signature highly expressed in plasmablasts by W48 compared to PBO; C4 levels modestly improved with FEN vs. PBO (Table 2).

Table 1.

SRI-4 Response (%) at W48 in Primary Analysis and in Post-hoc Patient Subgroups

PBOFEN 150 mg QDFEN 200 mg BIDSRI-4 Response (%) at W4844n=8451n=8752n=88SRI-4 Response (%) in Baseline Subgroups At least 1 BILAG A48n=4254n=3959n=46 At least 1 BILAG A and SLEDAI increased DNA binding37n=1953n=1765n=26 SLEDAI arthritis with at least 4 swollen joints39n=5750n=5457n=54 SLEDAI arthritis with at least 4 tender joints39n=7153n=7059n=69 CLASI >=1021n=1436n=1131n=16Table 2.

Key Biomarker Results

PBOFEN 150 mg QDFEN 200 mg BIDMedian (%) Change from Baseline at W48 Plasmablast signature-19.7%n=52-54.3%*n=53-51.7%*n=57 CD19+B cells (cells/µl)-0.50n=38-57.0*n=49-57.5*n=48 Anti-dsDNA#(IU/ml)+6.9n=31-38.3*n=36-75.7*n=33 Total IgG (g/L)-0.20n=65-1.25*n=64-1.56*n=64 C3 (g/L)-0.02n=65+0.01n=67-0.01n=66 C4 (g/L)0.00n=65+0.02*n=67+0.01*n=66

#Patients who were positive at baseline (>30 IU/mL)

*Denotes significant vs. PBO; Kruskal-Wallis false-discovery rate controlled two sided (p-value ≤0.05)

Conclusion:

The primary endpoint of SRI-4 for FEN was not met despite evidence of strong BTK target and pathway inhibition. FEN had an acceptable safety profile. Several disease activity subgroups were suggestive of a greater treatment effect on SRI-4 compared to PBO

Disclosure of Interests:

David Isenberg Consultant of: Study Investigator and Consultant to Genentech, Richard Furie Grant/research support from: AstraZeneca, Biogen, Consultant of: AstraZeneca, Biogen, Nicholas S. Jones Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Pascal Guibord Shareholder of: Roche, Employee of: Roche, Joshua Galanter Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Chin Lee Shareholder of: Genentech/Roche and Eli Lilly, Employee of: Genentech/Roche, Anna McGregor Employee of: Genentech/Roche, Balazs Toth Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Julie Rae Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Olivia Hwang Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Armend Lokku Shareholder of: Roche, Employee of: Roche, Pedro Miranda Consultant of: Study Investigator for Genentech, Viviane de Souza Consultant of: Study investigator for Genentech, Juan Jaller-Raad Consultant of: Study investigator for Genentech, Anna Maura Fernandes Consultant of: Study investigator for Genentech, Rodrigo Garcia Salinas Consultant of: Study investigator for Genentech, Leslie Chinn Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Michael J. Townsend Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Alyssa Morimoto Shareholder of: Genentech/Roche, Employee of: Genentech/Roche, Katie Tuckwell Shareholder of: Genentech/Roche, Employee of: Genentech/Roche

Abstract P1-09-05: Radiosensitization of androgen receptor (AR)-positive triple-negative breast cancer (TNBC) cells using seviteronel (INO-464), a selective CYP17 lyase and AR inhibitor

Background: Increased rates of locoregional recurrence (LR) have been observed in TNBC despite chemotherapy and radiation (RT). A novel radiosensitizer screen nominated the AR as a promising target for treatment of radioresistant breast cancer, including TNBC. We assessed the activity of seviteronel (Sevi), a selective CYP17 lyase and AR inhibitor in Phase 2 clinical development for advanced breast and prostate cancer, as a potential radiosensitizer in AR+ TNBC model.

Methods: Clonogenic survival assays were used to determine the intrinsic RT sensitivity of 21 breast cancer cell (BCC) lines. IC50 values were determined for 130 clinically available compounds and correlation coefficients were calculated using IC50 values and SF-2Gy. Gene expression was measured using RNA Seq or qRT-PCR and protein expression was measured using RPPA arrays. AR function was assessed using functional inhibition with Sevi in MDA-MB-453, ACC-422, ACC-460, SUM-185 (all four AR+ TNBC), MDA-MB-231 (AR- TNBC), and T47D (AR- ER+) BCC lines. Double-stranded DNA (dsDNA) break repair was assessed with γH2AX foci counting. In vivo tumor growth was measured with varying control and treatment groups (16-20 tumors/group). Kaplan-Meier analysis was performed to estimate local control. A Cox proportional hazards model and multi-variate analysis (MVA) were used to determine variables associated with LRF survival.

Results: Our novel radiosensitizer screen identified the activity of anti-androgen therapy as a potentially effective strategy for radiosensitization in RT-resistant BCC lines (R2 =0.46, p-value < 0.01) (Speers et al, J Clin Oncol 35, 2017 (suppl; abstr e12102). Heterogeneity in AR expression was identified in human BCC lines and TNBC samples from patients (N=2098). There was a strong correlation between AR RNA expression and protein expression across all BC intrinsic subtypes. AR inhibition using Sevi induced radiation sensitivity in vitro with an enhancement ratio (ER) of 1.24-1.69 in four different AR+ TNBC lines. No such radiosensitization was seen in AR(-) TNBC or ER+, AR(-) BCC lines. Radiosensitization was at least partially dependent on impaired dsDNA break repair with significant delays in dsDNA break repair at 16 and 24 hours in all AR+ TNBC lines examined (p-value < 0.01). AR inhibition with Sevi significantly radiosensitized AR+ TNBC xenografts in mouse models and markedly delayed tumor-volume tripling time (TTT) and tumor growth (MDA-MB-453: median TTT 16.1 days for RT alone vs. not reached after 45 days for Sevi+RT, p-value <0.001). Similar delays were seen in tumor growth, weight, and tumor doubling. Clinically, TNBC patients whose tumors had higher than median expression of AR had higher rates of LR after RT (HR for LR ˜3, p-value <0.01, 2 independent datasets). In MVA, high AR expression was the variable most significantly associated with worse LR survival after RT in TNBC patients, outperforming all other variables (HR of 3.42; p-value < 0.01).

Conclusions: Our results implicate the AR as a mediator of radioresistance in breast cancer and support the rationale for developing Sevi as a novel radiosensitizing agent in AR+ TNBC.

Citation Format: Speers CW, Chandler B, Olsen E, Wilder-Romans K, Moubadder L, Nyati S, Rae J, Hayes DF, Spratt DE, Wahl DR, Eisner J, Feng FY, Pierce LJ. Radiosensitization of androgen receptor (AR)-positive triple-negative breast cancer (TNBC) cells using seviteronel (INO-464), a selective CYP17 lyase and AR inhibitor [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-09-05.

Abstract P4-12-13: High intratumoral and stromal S100A8 expression is prognostic of poor outcome in breast cancer

Background: S100A8 and S100A9 are members of a family of calcium binding proteins that regulate inflammatory response, and are biomarkers of inflammatory diseases, S100A8/A9 preferentially form heterodimers that interact with their receptor, RAGE, to activate signaling pathways (ERK1/2 MAPK, JNK, and NF-κB) and stimulate tumor cells. Elevated expression of S100A8/A9 has been observed in cancers of the bladder, esophagus, colon, ovary, and breast. S100A8/A9 are expressed intratumorally by cancer cells and in the stroma by infiltrating immune and myeloid cells as well. We investigated the associations of elevated expression of intratumoral and stromal S100A8 with survival outcomes in breast cancer.

Methods: Tissue microarrays (TMA) were constructed from breast cancer specimens from patients with stage I-III breast cancer treated at the University of Michigan Comprehensive Cancer Center between 2004-2006, ensuring a minimum of 10-year follow-up. Each patient was represented on the TMA by representative regions of non-necrotic tumor and distant normal tissue. Automative Quantitative Immunofluorescence (AQUA) was performed for S100A8 protein, and samples were scored for intratumoral and stromal S100A8 expression. S100A8 staining was assessed as a continuous value and by exploratory dichotomous cutoffs. Associations with disease-free survival (DFS) or overall survival (OS) and S100A8 expression, either as continuous value or based on the exploratory cutoffs, were determined using the Kaplan-Meier method and Cox proportional hazards models.

Results: In the entire patient cohort, high intratumoral S100A8 expression, as a continuous measure, was a significant prognostic factor for OS (univariable hazard ratio [HR] 1.26, 95% confidence interval [CI] 1.02-1.56, p=0.036), and for DFS (multivariable HR [95%CI] = 1.24 [1.01-1.53], p = 0.043). Exploratory analyses demonstrated optimal cutoffs of intratumoral and intrastromal staining that greatly separated survival curves. We evaluated whether the prognostic significance of S100A8 expression is different in breast cancer patients based on hormone receptor status and determined that neither intratumoral nor stromal S100A8 expression were significantly associated with outcomes.

Conclusions: Elevated intratumoral and stromal expression of S100A8 are significant indicators of poor outcome in breast cancer patients. These data further support a biological role for S100A8 signaling in mammary carcinogenesis and aggressive tumor behavior. Evaluation of S100A8 protein expression might provide additional prognostic information beyond traditional breast cancer prognostic biomarkers. Further validation is necessary to investigate these findings.

Citation Format: Miller P, Kidwell K, Thomas D, Sabel M, Rae J, Hayes DF, Lippman ME, El-Ashry D. High intratumoral and stromal S100A8 expression is prognostic of poor outcome in breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-12-13.

A Single Nucleotide Polymorphism in Steroid Receptor Coactivator-1 Diminishes the Coactivation of ERα

Estrogen signaling is critical in the progression of a large fraction of breast cancers as well as in the maintenance of bone mineral density. Generally speaking, Tamoxifen, a selective estrogen receptor modulator (SERM), blocks estrogen signaling in the breast by acting as an antagonist at the same time as promoting estrogen signaling in the bone by acting as an agonist. This tissue specific action characteristic of SERMs is thought to be maintained by the balance of levels and/or activities of estrogen receptor (ER) coregulators. Because of this critical role, single nucleotide polymorphisms (SNPs) in ER coregulators could have a dramatic effect on tamoxifen action.Previous studies have implicated steroid receptor coactivator-1 (SRC-1) as a critical coregulator for the mixed antagonist-agonist specificity of tamoxifen. By using an ERE-Tk-Luciferase transient transfection assay, we have shown that a SNP causing the amino acid change P1272S in SRC-1 dramatically reduces its ability to coactivate ERα.To assess the impact of this SNP on tamoxifen action in breast cancer we decided to genotype the SRC-1 P1272S SNP in a breast tumor DNA bank. This bank was generated from archived tumors from individuals either exclusively receiving adjuvant tamoxifen or not receiving any adjuvant therapy following surgical resection. Currently, the bank is composed of 1000 samples divided equally among the two groups. Genotyping for the SRC-1 P1272S SNP is currently underway.Since SRC-1 has also been shown to be important in proper maintenance of bone mineral density (BMD) and in the agonist action of tamoxifen in certain tissues, we also assessed the impact of the P1272S SNP in bone following tamoxifen therapy. We genotyped breast cancer patients exclusively receiving tamoxifen therapy (i.e. no chemotherapy, no radiation) who had lumbar (n=113) and/or hip (n=108) BMD scans before and after 12 months of tamoxifen therapy. We observed a significant association between the SNP and bone loss; women harboring the P1272S SNP lost 6.4% of their lumbar BMD, while women with the WT version lost only 1.3% of their lumbar BMD.These findings illustrate the critical role of SRC-1 in tamoxifen action in bone, and potentially other hormone responsive tissues. Studies are ongoing to decipher the mechanism for decreased coactivation activity of the SNP, and also to extend the clinical association studies.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 66.

Development of a Novel GREB1 Monoclonal Antibody and Applications in Breast Cancer Research

It has been well established that GREB1 mRNA expression is induced by estrogen in breast cancers and that GREB1 is critically involved in the estrogen-induced growth of breast cancer. To date, all studies of GREB1 have focused on mRNA levels using PCR and array technologies with very little known about GREB1 protein expression in normal and breast cancer cells. The lack of a specific antibody to GREB1 has inhibited protein-based investigations in target cells. Our collaborative research group has generated a novel monoclonal GREB1 antibody (GREB1ab) for research use in Western blotting as well as immunohistochemical (IHC) applications.Our team created a hybridoma expressing a murine monoclonal antibody against a 119 amino acid peptide specific to human GREB1. By Western Blot Analysis, GREB1ab detects a 216 kD protein corresponding to GREB1a in ER+ breast cancer cells expressing GREB1 as well as cells transfected with a GREB1a expression plasmid. GREB1ab specificity was verified using ICI 182,780, an estrogen receptor antagonist to prevent GREB1 induction, as well as silencing siRNA targeting GREB1 mRNA expression. GREB1 protein expression was reduced in MCF-7 cells treated with estrogen plus ICI 182,780 compared with that of estrogen treatment. There was no detectable GREB1 protein expression when GREB1 mRNA is silenced by siRNA at 48 hours. In a time course study, inhibition of GREB1 protein occurred as early as 24 hours and lasted up to 72 hours. Thus, by Western Blot Analysis, the monoclonal GREB1ab is specific for GREB1 and can be employed to detect changes in GREB1 expression in breast cancer cell lines under various experimental conditions.GREB1ab was validated for detection of GREB1 by IHC in breast cancer cell lines and breast tissue microarrays (TMA). IHC staining with GREB1ab revealed GREB1 was strongly expressed in the ERα-positive breast cancer cell line, MCF-7, with weak GREB1 expression in ERα-negative MDA-231 cells. A panel of breast cancer cell lines was screened for endogenous expression of GREB1 protein in a TMA format using IHC. As expected, ER-positive cell lines (n=5) were observed to express GREB1 while ER-negative cell lines (n=11) did not express detectable levels. Using breast cancer tissue whole sections, IHC with the GREB1ab indicated protein expression in ERα positive breast cancer tissue as well as normal breast tissue, with little GREB1 expression in ERα negative breast cancer tissue.The monoclonal GREB1ab is specific for GREB1 protein. This antibody will serve as a tool for investigations focused on the expression, distribution and function of GREB1 in normal breast and breast cancer tissues.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2126.

Correlations between GREB1 Expression and Estrogen Receptor, HER2 Status in Human Breast Cancer

The two most common endocrine treatment modalities, anti-estrogen therapy and aromatase inhibitor therapy target estrogen receptor (ER) activation and estrogen (E2) biosynthesis, respectively. Although these therapies are effective in many patients with ER-positive tumors, prospective clinical trials have demonstrated that there exists a portion of patients with breast cancers that are initially responsive to endocrine therapy but subsequently relapse. Because of the lack of perfect correlation between ER and/or progesterone receptor (PR) status and patients who benefit from hormone therapy, there is a need to identify additional protein markers that would improve prediction of hormone response.Gene Regulated by Estrogen in Breast cancer 1 (GREB1) is regulated by estrogen (E2) in breast cancer and may serve as a candidate marker to predict response to endocrine therapy. The focus of this study was to define the significance of GREB1 protein expression in breast cancer and its correlation with estrogen receptor α status and epidermal growth factor receptor 2 (HER2) expression. Based on the query of 16 breast cancer expression array studies in the Oncomine Research database, GREB1 mRNA is expressed at greater levels in breast carcinomas than normal breast tissue (p value: 2.1E-5). In addition, GREB1 mRNA is significantly more commonly expressed in ER-positive breast cancer patients (n=1651) than ER-negative patients (n=670) (P value: 4.2E-5 ∼ 1.1E-34). Finally, GREB1 mRNA expression was observed to be lower in HER2+ breast cancer patients than in HER-2 – patients (p-value: 0.034). These mRNA expression data supported the hypothesis that GREB1 may have potential as a new biomarker for predicting E2-dependent and anti-E2 responsive breast cancers.Using a novel GREB1 monoclonal antibody generated by our laboratory, Immunohistochemical staining (IHC) was performed on a tissue microarrays containing invasive breast carcinomas from a cohort of 142 operable breast cancer patients (104 ER+ and 38 ER- cancers) with paired uninvolved tissue from the same patient. GREB1 protein was detected in both uninvolved normal tissue and ER+ breast cancer, but was absent in ER- tumors. Thus, IHC staining revealed GREB1 protein expression, predominantly localized in the cell nucleus, has a significant correlation with ER status (p-value <0.0001). Conversely, as observed in mRNA expression analysis, GREB1 protein levels inversely correlates with HER2 status (p-value <0.0001). Furthermore, decreased HER2 signaling caused by treatment with trastuzumab or lapatinib increased GREB1 (2-10 fold) and other ER target gene expressions, such as insulin receptor substrate 1 (IRS-1), insulin-like growth factor binding protein-4 gene (IGFBP4) and bcl-2 mRNA expression.These findings suggest, in addition to ER and PR, GREB1 may serve as a novel biomarker to distinguish patients who will benefit from tamoxifen therapy as well as identify anti-estrogen resistant breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2008.

Associations between estrogen receptor (ER) Alpha expression levels and ER genotypes

Abstract #3049

Background: Estrogen receptors (ER) and associated factors, including progesterone receptors (PgR), modulate estrogenic effects both in normal tissue and in hormone receptor (HR)-positive breast cancers. ERα expression occurs in the majority of breast cancers, although the level of overexpression varies between tumors. Multiple single nucleotide polymorphisms (SNPs) in the genes that encode ER, termed ESR1 (ERα) and ESR2 (ERβ), have been shown to affect phenotypic outcomes, including breast cancer risk, bone mineral density, hot flashes, and lipid levels. We hypothesized that SNPs in genes that encode ER may affect level of ER overexpression.
 Methods: DNA was extracted from white blood cells from 100 subjects with HR-positive breast cancer enrolled in a tamoxifen observational study. SNPs in ESR1 (XbaI: rs#9340799, PvuII: rs#2234693) and ESR2 (01: rs#1256049; 02: rs#4986938) were determined from germline DNA using TaqMan. ER overexpression in paraffin-embedded formalin-fixed tumor specimens was quantified with immunohistochemistry (IHC) of tumor specimens on slides (Ventana Image Analysis System) and with RT-PCR using the Oncotype DX breast cancer assay (Genomic Health, Inc). Gene expression of other ER-associated genes (PgR, BCL2, and SCUBE2) was determined using RT-PCR (Oncotype DX). Expression of ER and associated genes across ER genotype was performed using the Kruskal-Wallis test. For all analyses, a p value of <0.05 was considered statistically significant.
 Results: ER expression assessed using IHC and RT-PCR was statistically significantly correlated, with a Pearson correlation coefficient of 0.43 (p=0.0006). However, there was no association between the ESR1 or ESR2 genotypes and ER expression assessed by either method. A trend between ESR1 XbaI genotype and PgR expression by RT-PCR was noted (p=0.08 for gene-dose effect). No other associations between ER polymorphisms and expression of ER-related genes were identified.
 Conclusions: SNPs in genes encoding for ER do not appear to be associated with level of ER expression in breast cancer. Differences in ER expression between individual tumors are likely due to mechanisms other than these inherited mutations in the ER genes.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3049.

Impact of SNPs in ERα corepressor SMRT on breast cancer risk and response to endocrine therapy

Abstract #1043

Approximately 1/3 of hormone dependent breast cancers do not respond to tamoxifen treatment. The fact that these tumors are intrinsically resistant suggests that underlying genetic factors are responsible for this phenotype. The two major types of genetic variation are single nucleotide polymorphisms (SNPs) and copy number variations (CNVs). SNPs are the most common form of genetic alteration with an estimated 10 million SNPs across the genome and likely influence both disease susceptibility and response to therapy.
 Traditionally, researchers have attempted to identify SNPs associated with a clinical outcome in a “top-down” approach by conducting linkage and SNP association studies. However, here we report on a “bottom-up” approach whereby SNPs are first tested in vitro for a functional effect. This awards two benefits over a “top-down” approach: 1) identification of functional SNPs and 2) detailed characterization of the SNP so that the clinical association studies can be designed accordingly.
 Tamoxifen acts by blocking estradiol (E2) from binding to the estrogen receptor (ERα) and by recruiting corepressors, which then actively repress gene transcription. The critical role of corepressors, especially SMRT, in the proper action of tamoxifen makes them likely to be involved in tamoxifen resistance. Thus, we used a “bottom-up” approach to identify SNPs in ERα corepressors which affect the ability of tamoxifen to suppress ERα function.
 Here we report the detailed in vitro characterization of a number of SNPs in SMRT (NCoR2) with respect to altered ERα function in the presence of tamoxifen. Further, these SNPs are currently being genotyped so that associations can be made in a population of women receiving tamoxifen as either preventative or adjuvant therapy in which extensive surrogate markers for ERα function were collected during the 1-year follow (hot flash rate, hot flash intensity, lipid profiles, and bone mineral density).
 Through the discovery of common polymorphisms affecting Tamoxifen response, we hope to identify new diagnostic criteria to predict which patients will respond to anti-estrogen therapy and which will be better candidates for another line of therapy, such as aromatase inhibitors.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1043.

Improved prediction of disease-free survival in tamoxifen-treated patients using an expression signature of estrogen-regulated genes as compared to progesterone receptor

535

Background: Progesterone receptor (PR) is a direct downstream target of activated estrogen receptor (ER) and its expression is a marker of estrogen signaling within breast tumors. Studies suggest the absence of PR predicts the likelihood of distant recurrence in patients treated with hormonal therapies such as tamoxifen, but better clinical measures are needed. Methods: Through analysis of public mRNA expression profiling datasets, we identified 36 genes with the following expression patterns similar to PR: (1) induced by 17β-estradiol (E2) in estrogen receptor (ER)-positive breast cancer cell lines in vitro, (2) under-expressed in ER-negative compared to ER-positive breast tumors, and (3) correlated with PR expression in ER-positive tumors. The average expression of these 36 genes was used as a “risk index” for assessing disease-specific survival in two independent tumor profile datasets of 60 and 67 patients treated with tamoxifen (these data not having been used to initially select the 36 genes), with a high risk group in each dataset defined as those with the bottom 25% of risk index values. Results: The Kaplan-Meier estimates of the rates of distant recurrence at 10 years in the low-risk and high-risk groups were 24% and 64% in the one dataset and 32% and 72% in the other dataset. In both validation datasets, the rate in the low-risk group was significantly lower than that in the high-risk group (P=0.008 and P=0.006 by log-rank, respectively), whereas patient groups defined by histologically-assigned PR status did not show significant risk differences (P=0.70 and P=0.94, respectively). In a univariate Cox model, the risk index combined across both validation datasets provided significant predictive power (P=0.03). Conclusions: Through RT-PCR assay of a larger independent cohort of breast tumor samples, we are currently validating the prognostic value of individual genes within the 36-gene signature.

No significant financial relationships to disclose.

Underlying chronic granulomatous disease in a patient with bronchocentric granulomatosis

We present a case of bronchocentric granulomatosis in a woman with no history of asthma who was colonised with Aspergillusfumigatus. A family history of chronic granulomatous disease prompted further testing that demonstrated severely depressed neutrophil oxidant production and gp91(phox) deficiency compatible with the X linked carrier state of chronic granulomatous disease. Only one report of the association of these two rare diseases has previously appeared in the literature. We postulate that an ineffective immune response led to the prolonged colonisation of Afumigatus resulting in a hypersensitivity reaction that was manifest clinically as bronchocentric granulomatosis.

Singing seizures

Automatisms are commonly seen in epilepsy, either ictally or postictally. However, most automatisms are simple, with hand movements, mouth smacking, nose-rubbing, repetition of a single word, or coughing, grunting, or screeching. Complex automatisms are less common and striking. The authors report two cases of seizure-associated singing where song expression may be recognizable.

Induction of gp91-phox, a component of the phagocyte NADPH oxidase, in microglial cells during central nervous system inflammation

Gp91-phox is an integral component of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex that generates reactive oxygen species (ROS) in activated circulating phagocytes. The authors previously demonstrated that gp91-phox knockout (KO) mice show significant protection from neuronal injury after cerebral ischemia--reperfusion injury, suggesting a pivotal role for this enzyme. Moreover, results from chimeric mice suggested that elimination of gp91-phox from both circulating phagocytes and a putative central nervous system (CNS) source were required to confer neuroprotection. In the current study, the authors demonstrated gp91-phox-specific immunostaining of perivascular cells in the CNS of control rats. However, after transient cerebral ischemia, gp91-phox-positive phagocytes were observed within the core ischemic region and activated microglial cells were positive in the penumbra. Such activated microglial cells were also gp91-phox-positive in the CNS of a chimpanzee with mild meningitis. Finally, in humans, both normal adult CNS tissues and isolated fetal microglial cells expressed gp91-phox mRNA. These microglia also expressed mRNA for the five other known components that comprise the NADPH oxidase complex. These data strongly suggest that microglial cells may contain a functionally active NADPH oxidase capable of generating ROS during CNS inflammation.

High resolution mapping of the binding site on human IgG1 for Fc gamma RI, Fc gamma RII, Fc gamma RIII, and FcRn and design of IgG1 variants with improved binding to the Fc gamma R

Immunoglobulin G (IgG) Fc receptors play a critical role in linking IgG antibody-mediated immune responses with cellular effector functions. A high resolution map of the binding site on human IgG1 for human Fc gamma RI, Fc gamma RIIA, Fc gamma RIIB, Fc gamma RIIIA, and FcRn receptors has been determined. A common set of IgG1 residues is involved in binding to all Fc gamma R; Fc gamma RII and Fc gamma RIII also utilize residues outside this common set. In addition to residues which, when altered, abrogated binding to one or more of the receptors, several residues were found that improved binding only to specific receptors or simultaneously improved binding to one type of receptor and reduced binding to another type. Select IgG1 variants with improved binding to Fc gamma RIIIA exhibited up to 100% enhancement in antibody-dependent cell cytotoxicity using human effector cells; these variants included changes at residues not found at the binding interface in the IgG/Fc gamma RIIIA co-crystal structure (Sondermann, P., Huber, R., Oosthuizen, V., and Jacob, U. (2000) Nature 406, 267-273). These engineered antibodies may have important implications for improving antibody therapeutic efficacy.

Transplantation of a fetus with paternal Thy-1(+)CD34(+)cells for chronic granulomatous disease

A fetus diagnosed with X-linked chronic granulomatous disease was transplanted with Thy-1(+)CD34(+) cells of paternal origin. The transplant was performed at 14 weeks gestation by ultrasound guided injection into the peritoneal cavity. The fetus was delivered at 38 weeks gestation after an otherwise uneventful pregnancy. Umbilical cord blood was collected and used to determine the level of peripheral blood chimerism as well as levels of functional engrafted cells. Flow cytometry was used to detect donor leukocytes identified as HLA-A2(-)B7(+) cells, whereas recipient cells were identified as HLA-A2(+)B7(-) cells. No evidence of donor cell engraftment above a level of 0.01% was found. PCR was used to detect HLA-DRB1*15(+) donor cells among the recipient's HLA-DRB1*15(-) cells, but no engraftment was seen with a sensitivity of 1:1000. The presence of functional, donor-derived neutrophils was assessed by flow cytometry using two different fluorescent dyes that measure reactive oxygen species generated by the phagocyte NADPH oxidase. No evidence of paternal-derived functional neutrophils above a level of 0.15% was observed. Peripheral blood and bone marrow samples were collected at 6 months of age. Neither sample showed engraftment by HLA typing using both flow cytometry and PCR. Functional phagocytes were also not observed. Furthermore, no indication of immunological tolerance specific for the donor cells was indicated by a mixed lymphocyte reaction assay performed at 6 months of age. While there appears to be no engraftment of the donor stem cells, the transplant caused no harm to the fetus and the child was healthy at 6 months of age. Analyses of fetal tissues, obtained from elective abortions, revealed that CD3(+) T cells and CD56(+)CD3(-) NK cells are present in the liver at 8 weeks gestation and in the blood by 9 weeks gestation. The presence of these lymphocytes may contribute to the lack of donor cell engraftment in the human fetus.

Autosomal recessive chronic granulomatous disease caused by defects in NCF-1, the gene encoding the phagocyte p47-phox: mutations not arising in the NCF-1 pseudogenes

Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by defects in any one of 4 genes encoding phagocyte NADPH oxidase subunits. Unlike other CGD subtypes, in which there is great heterogeneity among mutations, 97% of affected alleles in patients previously reported with A47(0) CGD carry a single mutation, a GT deletion (DeltaGT) in exon 2 of the p47-phox gene, NCF-1. This unusually high incidence results from recombination events between NCF-1 and its highly homologous pseudogenes, in which DeltaGT originates. In 50 consecutive patients with A47(0) CGD, 4 were identified who were heterozygous for DeltaGT in NCF-1, and for the first time, 2 were identified whose DNA appeared normal at this position. To avoid co-amplification of pseudogene sequence and to enable the identification of mutations in these patients, allele-specific polymerase chain reaction was used to amplify alleles not containing DeltaGT. In each of the 4 patients who were heterozygous for DeltaGT, an additional novel mutation was identified. These were 2 missense mutations, G125 --> A in exon 2 (predicting Arg42 --> Gln) and G784 --> A in exon 8 (Gly262 --> Ser), and 2 splice junction mutations at the 5' end of intron 1, gt --> at and gtg --> gtt. The first of 2 patients who appeared normal at the GT position was a compound heterozygote with the G125 --> A transition on one allele and a deletion of G811 on the other. In the second of these patients, only a single defect was detected, G574 --> A, which predicts Gly192 --> Ser but is likely to result in defective splicing because it represents the final nucleotide of exon 6.

Molecular analysis of 9 new families with chronic granulomatous disease caused by mutations in CYBA, the gene encoding p22(phox)

Chronic granulomatous disease is a rare inherited disorder caused by nonexistent or severely decreased phagocyte superoxide production that results in a severe defect in host defense and consequent predisposition to microbial infection. The enzyme responsible for generating the superoxide, NADPH oxidase, involves at least 5 protein components. The absence of, or a defect in, any 1 of 4 of these proteins (p22(phox), p47(phox), p67(phox), or gp91(phox)) gives rise to the known types of chronic granulomatous disease. One of the rarest forms of the disease is due to defects in the CYBA gene encoding p22(phox), which together with gp91(phox) forms flavocytochrome b(558), the catalytic core of NADPH oxidase. To date, only 9 kindreds with p22(phox) deficiency have been described in the literature comprising 10 mutant alleles. Four polymorphisms in the CYBA gene have also been reported. Here we describe 9 new, unrelated kindreds containing 12 mutations, 9 of which are novel. In addition, we report 3 new polymorphisms. The novel mutations are (a) deletion of exons 2 and 3, (b) a missense mutation in exon 3 (T155-->C), (c) a splice site mutation at the 5' end of intron 3, (d) a missense mutation in exon 2 (G74-->T), (e) a nonsense mutation in exon 1 (G26-->A), (f) a missense mutation in exon 4 (C268-->T), (g) a frameshift in exon 3 due to the insertion of C at C162, (h) a nonsense mutation in exon 2 (G107-->A), and (i) a missense mutation in exon 2 (G70-->A).

Recombination events between the p47-phox gene and its highly homologous pseudogenes are the main cause of autosomal recessive chronic granulomatous disease

Chronic granulomatous disease (CGD) is an inherited disease caused by defects in the superoxide-generating nicotinamide adenine dinucleotide phosphate (NADPH) oxidase of phagocytes. Genetic lesions in any of 4 components of this antimicrobial enzyme have been detected. Family-specific mutations are found in 3 of 4 forms of CGD due to deficiencies of the gp91-phox, p22-phox, and p67-phox genes. In p47-phox-deficient CGD (autosomal recessive form A47 degrees ) patients, a GT deletion (triangle upGT) at the beginning of exon 2 of the p47-phox gene has been reported in 19 of 20 alleles. This GT deletion is also characteristic for the recently identified p47-phox pseudogenes. To explore a possible link between these findings, a sequence analysis of 28 unrelated, racially diverse A47 degrees CGD patients and 37 healthy individuals was performed. The GT deletion in exon 2 was present on all alleles in 25 patients. Only 3 patients but all healthy individuals contained the GTGT and triangle upGT sequences. A total of 22 patients carried additional pseudogene-specific intronic sequences on all alleles, either only in intron 1 or in intron 1 and intron 2, which lead to different types of chimeric DNA strands. It is concluded that recombination events between the p47-phox gene and its highly homologous pseudogenes result in the incorporation of triangle upGT into the p47-phox gene, thereby leading to the high frequency of GT deletion in A47 degrees CGD patients. (Blood. 2000;95:2150-2156)

Autosomal recessive chronic granulomatous disease caused by novel mutations in NCF-2, the gene encoding the p67-phox component of phagocyte NADPH oxidase

Chronic granulomatous disease (CGD) is a rare inherited immunodeficiency disease that leads to severe recurrent infections. CGD is caused by defects in the phagocyte NADPH oxidase, a multiprotein enzyme that reduces oxygen to superoxide, a precursor of microbicidal oxidants. Less than 6% of CGD patients have an autosomal recessive form of the disease caused by mutations in NCF-2. This gene encodes p67-phox, a cytosolic oxidase subunit that associates with membrane-bound flavocytochrome b558 and regulates electron transfer. We studied six patients from five families with p67-phox deficiency and identified seven different mutant alleles. Patients from three of the kindreds were homozygous for their respective mutation, although the parents of only one family were known to be related. Five of the mutations have not previously been identified: (1) a missense mutation (383C-->T) in exon 5, (2) a nonsense mutation (196C-->T) in exon 3, (3) a missense mutation (230G-->A) in exon 3, (4) a nonsense mutation (298C-->T) in exon 4, and (5) a dinucleotide deletion (835-836 AC) from exon 9. Phagocytes from each of the patients analyzed failed to generate a measurable respiratory burst and had no detectable p67-phox protein. Our results further demonstrate that there is great heterogeneity among the mutations in p67-phox-deficient CGD patients, with no evidence for mutational hot-spots or a founder effect. Our data also support the hypothesis that the stability of p67-phox is particularly sensitive to missense mutations that cause amino acid substitutions within its N-terminal domain. In contrast, mutations predicting single amino acid changes elsewhere in the protein generally represent benign polymorphisms.

Molecular characterization of autosomal recessive chronic granulomatous disease caused by a defect of the nicotinamide adenine dinucleotide phosphate (reduced form) oxidase component p67-phox

Chronic granulomatous disease (CGD) is a rare inherited disorder of phagocytes in which defective production of microbicidal oxidants leads to severe recurrent infections. CGD is caused by mutations in any of 4 genes encoding components of nicotinamide adenine dinucleotide phosphate (reduced form; NADPH) oxidase, the multisubunit enzyme that produces the precursor of these oxidants, superoxide. Approximately 5% of CGD patients have an autosomal recessive form of disease caused by a severe deficiency of p67-phox, a 526-amino acid subunit of the oxidase that appears to regulate electron transport within the enzyme. Here we report the biochemical and molecular characterization of 6 unrelated kindreds with p67-phox deficiency. These studies show that, as in gp91-phox and p22-phox deficiencies, the p67-phox CGD patients show a high degree of heterogeneity in the genetic defects that underlie their disease. Five different mutant alleles were identified: (1) a nonsense mutation in exon 4 (C(304) --> T); (2) a 5-nucleotide (nt) deletion in exon 13 (nts 1169-1173); (3) a splice mutation in the first nucleotide of intron 4 (G --> A); (4) a deletion of 1 nt in exon 9 (A(728)); and (5) a 9-nt in-frame deletion in exon 2 (nts 55-63). The splice mutation was seen in 3 unrelated kindreds, while the 5-nt deletion was seen in 2 apparently unrelated families (both of Palestinian origin). Homozygosity was present in 4 of the kindreds, 2 of which had consanguineous parentage. In the isolated neutrophils of each of the affected patients in the 6 kindreds, there was no measurable respiratory burst activity and no p67-phox protein detected by immunoblot analysis. The level of 67-phox mRNA was less than 10% of normal in the mononuclear leukocytes from 3 of the 4 patients analyzed by Northern blot studies. Thus, this heterogeneous group of mutations in p67-phox all lead to marked instability of mRNA or protein (or both) that results in the complete loss of NADPH oxidase activity.

A novel mutation in the CYBB gene resulting in an unexpected pattern of exon skipping and chronic granulomatous disease

Chronic granulomatous disease is a rare inherited disorder caused by non-existent or severely decreased phagocyte superoxide production that results in a severe defect in host defense and consequent predisposition to microbial infection. The enzyme responsible for superoxide production, NADPH oxidase, involves at least five components. An absence of, or a defect in, any one of four of these proteins (p47(phox), p67(phox), p22(phox) and gp91(phox)) gives rise to the known types of chronic granulomatous disease. The most common form of inheritance is X-linked and is due to mutations in the CYBB gene that encodes gp91(phox), the large subunit of flavocytochrome b, the terminal electron donor of the oxidase. We have recently reported a large number of mutations in this gene revealing a broad range of defects, including large and small deletions, and frameshift, nonsense, missense, splice region and regulatory region mutations. Here we report a patient who has an unusual type of mutation that results in the generation of a 'pseudo-exon' in the gp91(phox) mRNA and an unexpected pattern of splicing.

Host defense molecule polymorphisms influence the risk for immune-mediated complications in chronic granulomatous disease

Chronic granulomatous disease (CGD) is an inherited disorder of phagocyte function in which defective superoxide production results in deficient microbicidal activity. CGD patients suffer from recurrent, life-threatening infections, and nearly half develop chronic gastrointestinal (GI) complications (colitis, gastric outlet obstruction, or perirectal abscess) and/or autoimmune/rheumatologic disorders (AIDs). To identify genetic modifiers of disease severity, we studied a cohort of 129 CGD patients, in whom seven candidate genes (myeloperoxidase [MPO], mannose binding lectin [MBL], Fcgamma receptors IIa, IIIa, IIIb, TNF-alpha, and IL-1 receptor antagonist), each containing a physiologically relevant polymorphism predicted to influence the host inflammatory response, were selected for analysis. Genotypes of MPO (P = 0.003) and FcgammaRIIIb (P = 0.007) were strongly associated with an increased risk for GI complications, while an FcgammaRIIa (P = 0.05) genotype was suggestive for an association. Patients with all three associated genotypes had the highest risk for GI complications (P < 0.0001). The risk of AIDs was strongly associated with variant alleles of MBL (P = 0.01) and weakly associated with an FcgammaRIIa genotype (P = 0.04). Patients with variant forms of both MBL and FcgammaRIIa had the highest risk of developing an AID (P = 0.003).

Lifetime health risk assessment from exposure of recreational users to polycyclic aromatic hydrocarbons

In order to assess the lifetime risk of skin cancer for recreational users from dermal exposure to polycyclic aromatic hydrocarbons (PAHs), sediment samples were collected from beach sites along the St. Marys River near Sault Ste. Marie, Ontario, and in Hamilton Harbor and Toronto Harbor, Ontario, and analyzed for PAHs. Dermal exposure and lifetime skin cancer risk were estimated as follows: Concentrations of 11 PAHs with sufficient or limited evidence of carcinogenicity or mutagenicity were converted to benzo(a)pyrene (BaP) equivalents using toxic equivalency factors (TEFs). Lifetime dermal exposure values were derived based on the BaP equivalents in the silt + clay fraction taken as representative of suspended sediment particulates to which recreational users would be exposed. The lifetime health risk of skin cancer associated with such exposures was above the negligible risk level of 1.0 x 10(-6) at offshore Rytac, Lake George Channel, and Bell Point beaches in the St. Marys River; at Pier 4 Park in Hamilton Harbor; and at Humber Bay, Sunnyside Beach, Cherry Beach, and Water Rats Sailing Club in Toronto Harbor. Risk was negligible inshore at the Rytac and Bell Point beaches and at Squirrel Island and Ojibway Trailer Park along St. Marys River, at Lax Beach in Hamilton Harbor; and at Centre Island in Toronto Harbor. Strategies to reduce risk were developed with these communities; a key recommendation was to take a bath or shower within 24 h after a swim because virtually all the PAHs on the skin would be removed.

X-Linked chronic granulomatous disease: mutations in the CYBB gene encoding the gp91-phox component of respiratory-burst oxidase

Chronic granulomatous disease (CGD) is a hereditary disorder of host defense due to absent or decreased activity of phagocyte NADPH oxidase. The X-linked form of the disease derives from defects in the CYBB gene, which encodes the 91-kD glycoprotein component (termed "gp91-phox") of the oxidase. We have identified the mutations in the CYBB gene responsible for X-linked CGD in 131 consecutive independent kindreds. Screening by SSCP analysis identified mutations in 124 of the kindreds, and sequencing of all exons and intron boundary regions revealed the other seven mutations. We detected 103 different specific mutations; no single mutation appeared in more than seven independent kindreds. The types of mutations included large and small deletions (11%), frameshifts (24%), nonsense mutations (23%), missense mutations (23%), splice-region mutations (17%), and regulatory-region mutations (2%). The distribution of mutations within the CYBB gene exhibited great heterogeneity, with no apparent mutational hot spots. Evaluation of 87 available mothers revealed X-linked carrier status in all but 10. The heterogeneity of mutations and the lack of any predominant genotype indicate that the disease represents many different mutational events, without a founder effect, as is expected for a disorder with a previously lethal phenotype.

Phase I trial of orally administered pentosan polysulfate in patients with advanced cancer

Tumor angiogenesis is critically important to tumor growth and metastasis. We have shown that pentosan polysulfate (PPS) is an effective inhibitor of heparin-binding growth factors in vitro and can effectively inhibit the establishment and growth of tumors in nude mice. Following completion of our Phase I trial of s.c. administered PPS, we performed a Phase I trial of p.o. administered PPS in patients with advanced cancer to determine the maximum tolerated dose (MTD) and toxicity profile and to search for any evidence for biological activity in vivo. Patients diagnosed with advanced, incurable malignancies who met standard Phase I criteria and who did not have a history of bleeding complications were enrolled, in cohorts of three, to receive PPS p.o. t.i.d., at planned doses of 180, 270, 400, 600, and 800 mg/m2. Patients were monitored at least every 2 weeks with physical exams and weekly with hematological, chemistry, stool hemoccult, and coagulation blood studies, and serum and urine samples for PPS and basic fibroblastic growth factor (bFGF) levels were also taken. The PPS dose was escalated in an attempt to reach the MTD. Eight additional patients were enrolled at the highest dose to further characterize the toxicity profile and biological in vivo effects of PPS. A total of 21 patients were enrolled in the three cohorts of doses 180 (n = 4), 270 (n = 3), and 400 (n = 14) mg/m2. The most severe toxicities seen were grade 3 proctitis and grade 4 diarrhea; however, 20 of the 21 patients had evidence of grade 1 or 2 gastrointestinal (GI) bleeding. These toxicities became evident at a much earlier time point as the dose was increased, but their severities were similar at all dose levels. There were no objective responses, although three patients had prolonged stabilization of previously progressing disease. Pharmacokinetic analysis suggested marked accumulation of PPS upon chronic administration. Serum and urine bFGF levels failed to show a consistent, interpretable pattern; however the data suggested an inverse relationship between PPS and bFGF levels in vivo. A MTD could not be determined using the daily t.i.d. dosing schedule due to the development of grade 3/4 GI toxicity (proctitis) at all dose levels studied. PPS, administered p.o. at doses of 400 mg/m2 t.i.d., did not cause significant systemic toxicity, but most patients developed moderate-to-severe GI toxicity within 1-2 months. The cause of the GI toxicity was unclear, but it was readily reversible upon cessation of the agent. The suggestion of an inverse relationship between PPS and bFGF supports further study of PPS as an antiangiogenic agent. The tested doses and schedule cannot be recommended for further study. Subsequent murine experiments showed PPS to be more effective as an anticancer agent when it is given intermittently. We propose a study of PPS given on a weekly schedule in further clinical trials.

Ischemic stroke injury is reduced in mice lacking a functional NADPH oxidase

BACKGROUND AND PURPOSE

Free radicals account for a significant proportion of the brain damage that occurs during ischemic stroke. Using mutant mice (X-CGD) with a dysfunctional phagocytic NADPH oxidase, we investigated the role of this superoxide-generating enzyme as a mediator of the reperfusion injury in a mouse model of middle cerebral artery occlusion.

METHODS

Transient (2 hour) middle cerebral artery occlusion was performed in X-CGD or wild-type litter mates (8- to 10-week-old). After 22 hours of reperfusion, brains were harvested and infarct volume delineated using 2,3,5-triphenyl-tetrazolium chloride. To elucidate the origin of the damaging NADPH oxidase, transient ischemia was also performed in X-CGD or wild-type mice transplanted with wild-type C57 B1/6J or X-CGD bone marrow, respectively.

RESULTS

The infarct volume induced by transient ischemia was significantly less in X-CGD mice (29.1 +/- 5.6 mm3; n = 13) than wild-type littermates (54.0 +/- 10.6 mm3; n = 10; P < .05). The elimination of a functional NADPH oxidase from either the circulation or the central nervous system, by performing the appropriate bone marrow transplant experiments, did not reduce the infarct size induced by transient ischemia. This suggests that in order to confer protection against transient ischemia and reperfusion, a putative neuronal and circulating NADPH oxidase need to be inactivated.

CONCLUSIONS

Brain injury was reduced in mice lacking a functional NADPH oxidase in both the central nervous system and peripheral leukocytes, suggesting a pivotal role for the NADPH oxidase in the pathogenesis of ischemia-reperfusion injury in the brain.

Increased phagocyte Fc gammaRI expression and improved Fc gamma-receptor-mediated phagocytosis after in vivo recombinant human interferon-gamma treatment of normal human subjects

Recombinant human interferon-gamma (rhIFN-gamma) decreases the frequency of serious infections in patients with chronic granulomatous disease (CGD) through an unknown mechanism. To test the hypothesis that it exerts a beneficial effect by enhancing clearance of microbes from the bloodstream and tissues, normal human subjects were treated in vivo with rhIFN-gamma. Phagocyte opsonic receptor expression, serum opsonin levels, and phagocytosis of bacteria were then measured. A 4.7-fold increase in neutrophil expression of the high-affinity Fc gamma-receptor (Fc gammaRI) was observed that peaked 48 hours after the initiation of rhIFN-gamma treatment (P < .05). Monocyte expression of Fc gammaRI, Fc gammaRII, Fc gammaRIII, CD11a, CD11b, CD18, and HLA-DR also significantly increased with peak expression at 48 hours. Phagocytosis by neutrophils of killed Staphylococcus aureus opsonized with heat-inactivated pooled human serum significantly improved after rhIFN-gamma treatment (P < .05) and correlated with Fc gammaRI expression by neutrophils (r = .8, P < .001). This increase in ingestion could be inhibited by anti-Fc gammaRI monoclonal antibodies. Levels of the serum opsonin lipopolysaccharide-binding protein also significantly increased after in vivo rhIFN-gamma (P < .05). These results suggest that the protective effect of rhIFN-gamma in patients with CGD may involve improved microbial clearance. Moreover, improved phagocyte trafficking may occur secondary to increased expression of monocyte beta2-integrins. Because these IFN-gamma-related improvements in host defense were seen in normal hosts, rhIFN-gamma may have broader applications in the treatment of various disorders of immunity in addition to its demonstrated efficacy in CGD.

Dye transfer between cells of the lens

Dye transfer between lens fiber cells and between lens epithelial cells and underlying fiber cells was studied using a wide dynamic range-cooled CCD camera, H2O immersion objectives and image analysis techniques. Each lens was decapsulated by a new technique which leaves the epithelial cells adherent to the lens fiber mass. Lucifer Yellow CH was injected into either single epithelial cells or single fiber cells using the standard whole cell configuration of the patch voltage clamp technique. The results demonstrate extensive dye communication between fiber cells at the lens posterior surface, anterior surface, and equatorial surface. Dye transfer between deep fiber cells was also observed. Dye transfer between approximately 10% of epithelial cells and their underlying fiber cells was apparent when care was taken to yield wide dynamic range images. This was required because the relatively high concentration of dye in the epithelial cell masks the presence of much lower dye concentrations in the underlying fiber cell. A mathematical model which includes dye concentration, time, and spatial spread suggests that those epithelial cells that are coupled to an underlying fiber cell are about as well dye coupled as the epithelial cells themselves. The relatively low dye concentration in a fiber cell is due to its larger volume and diffusion of the dye along the axis of the fiber away from the fiber/epithelial junction.

Newborn screening for cystic fibrosis: Educational implications

We examined the educational implications of newborn screening for cystic fibrosis (CF) as performed by combining the measurement of immunoreactive trypsin with analysis for the most common CF mutation, ΔF508. Four out of 77 (5%) of maternity staff from 11 hospitals in rural New South Wales, Australia had learned about the salient features of the screening protocol from a pamphlet distributed from a central laboratory. In comparison, a didactic lesson resulted in a significantly greater (p<0.00006) number of maternity staff learning about the salient features of the screening protocol. Most maternity staff expanded their explanation to parents of newborn babies because of the didactic lesson.

Cytochrome b-245 of the neutrophil superoxide-generating system contains two nonidentical hemes. Potentiometric studies of a mutant form of gp91phox

Analysis of potentiometric titrations of the cytochrome b-245 from a X+ chronic granulomatous disease patient with an Arg54 --> Ser mutation in gp91phox indicates that the mutant form of the cytochrome contains two nonidentical hemes with midpoint potentials of Em7 = -220 and Em7 = -300 mV. In the light of this information, reanalysis of redox titrations of wild-type cytochrome b-245 implies that it probably also contains two separate heme centers with midpoint potentials of Em7 = -225 and Em7 = -265 mV. The effect of the Arg54 --> Ser substitution is to reduce the midpoint potential of one of the heme centers by approximately 35 mV and suggests possible interaction between Arg54 and a heme propionate side chain.

A variant X-linked chronic granulomatous disease patient (X91+) with partially functional cytochrome b

Genetic analysis of a patient with the variant cytochrome b-245-positive form of chronic granulomatous disease revealed a missense mutation resulting in a Arg54-->Ser substitution in the gp91phox subunit of cytochrome b-245. As a consequence, although no O2- is made, NADPH oxidase-associated FAD accepts electrons from NADPH in the cell-free activation system and becomes reduced. The reduced flavin exhibits normal levels of iodonitrotetrazolium violet diaphorase activity, and the patient's neutrophils exhibit high levels of intracellular oxidant production and show a low level of NBT staining in the NBT slide test. Thus, this mutation appears to render the heme center of NADPH oxidase present but nonfunctional, while leaving the flavin center fully functional.

A new X-linked variant of chronic granulomatous disease characterized by the existence of a normal clone of respiratory burst-competent phagocytic cells

Chronic granulomatous disease (CGD) is characterized by recurrent infections, and is usually associated with a complete inability of phagocytic cells to generate superoxide anion (O2-). Rarely, variant forms of CGD have been reported in which there is reduced, but detectable, O2- production by phagocytic cells. We describe three adult males in two kindreds with a unique form of X-linked cytochrome b558-deficient (X91-) CGD not previously reported. All three patients had two distinct populations of phagocytic cells, with one subset capable of normal respiratory burst activity and the other larger subset inactive, as in classic CGD (X91 (0)). The respiratory burst activity in neutrophils purified from each patient was approximately 10% of normal as determined by O2- production, O2 consumption, cytochrome b558 spectroscopy, and membrane oxidase activity using a cell-free activation system. In contrast with other patients with X91(-)-variant CGD, the unique feature of these patients is the presence of a small but significant population (5% to 15%) of circulating neutrophils and monocytes with completely normal respiratory burst activity as assessed by nitroblue tetrazolium (NBT) reduction and flow-cytometric measurement of dihydrorhodamine oxidation. NBT reduction of peripheral blood granulocyte-macrophage progenitor cells also showed the presence of a subset of colonies derived from myeloid progenitor cells that had normal respiratory burst capabilities. A mosaic XX chromosome karyotype and an unstable oxidase complex that might occur during myeloid maturation were both excluded as possible explanations. In these families, the molecular defect in the gp91-phox gene, which is currently under investigation, appears to prevent expression of the gene in the majority of neutrophils, but not in a small subset. Our studies suggest that commitment to either a respiratory burst-competent or -incompetent phagocytic cell occurs at the level of the myeloid progenitor cell.

Scalp-ear-nipple syndrome: additional manifestations

Scalp-ear-nipple (SEN) syndrome is a rare, autosomal dominant condition that causes aplasia cutis congenita of the scalp, alteration of the shape of the external ear, and hypoplasia of the nipple. Women in a new family, the fifth to be described, had virtually complete aplasia of the breast and a small skin dimple without any pigmentation instead of a normal nipple, although other affected women had normal breast and nipple development. Dental changes included widely spaced or missing secondary teeth; the ears were cupped or folded and stood out from the head, axillary apocrine secretion and axillary hair growth were reduced; and finger nails were brittle. There was no generalized abnormality of sweating. Some patients had partial syndactyly of the 3rd and 4th fingers, and complete cutaneous syndactyly of the 2nd and 3rd toes. and 3rd toes.

Effect of volume changes on a potassium current in rabbit corneal epithelial cells

Patch-clamp recordings from rabbit corneal epithelial cells have identified a large-conductance (167 pS in symmetrical 150 mM KCl) K channel that is the major contributor to the whole cell current (J. L. Rae and G. Farrugia. J. Membr. Biol. 129: 81-87, 1992). We report here on the regulation of this channel by changes in cellular osmolality and/or volume. Exchanging the bath solution with a hyposmotic (225 or 150 mosM) solution resulted in cellular swelling and selective activation of the K current (126 +/- 86 and 273 +/- 184% increase, respectively). Hyperosmotic solution changes (380 mosM) resulted in cell shrinkage and deactivation of the K current (44.2 +/- 21% decrease). Similar increases in the cell volume and whole cell current were observed on increasing (in perforated patch experiments) the chloride ion concentration (50 mM) in the pipette intracellular solution (127 +/- 63% increase). These changes were accompanied by marked shifts in the resting membrane voltage. We conclude that the K channels in these cells can respond to alteration in cellular osmolality or volume, resulting in changes in the whole cell current and resting voltage.

Potassium currents from isolated frog lens epithelial cells

Using the perforated patch version of whole-cell recording, we have measured currents from isolated frog lens epithelial cells. Three types of currents were seen. A time-independent outwardly rectifying potassium current was identified that sets the resting voltage. This potassium current differs significantly from any of the potassium currents recorded with the whole-cell technique in mammalian lens epithelial cells. In addition to the potassium current, the two other currents present were both outwardly rectifying: one was time-independent while the other showed distinct activation.

Prolonged recombinant interferon-gamma therapy in chronic granulomatous disease: evidence against enhanced neutrophil oxidase activity

Recombinant interferon-gamma (rIFN-gamma) therapy has become an effective form of prophylaxis for patients with chronic granulomatous disease (CGD). Preliminary studies with CGD suggested that rIFN-gamma treatment enhanced phagocyte oxidase activity and increased superoxide (O2-) production. We evaluated several aspects of neutrophil NADPH oxidase activity in 19 CGD patients (representing all four known types of CGD) receiving prolonged rIFN-gamma therapy (6 to 27 months). In contrast to earlier studies, we failed to detect any improvement in neutrophil NADPH oxidase activity in 18 of the 19 CGD patients as determined by (1) intact cell O2- production (continuous assay), (2) nitroblue tetrazolium (NBT) staining, (3) cytochrome b558 spectroscopy, and (4) activity levels of cytosol and membrane oxidase components using a cell-free activation system. One patient with a variant form of X-linked CGD had a transient increase in neutrophil O2- production following 3 months of rIFN-gamma therapy. However, this was not sustained, and was not associated with any change in cytochrome b levels. In some patients, rIFN-gamma therapy was associated with the appearance of a small subset of circulating monocytes (1% to 20%) that were NBT-positive. Although the functional significance of this monocyte subpopulation needs to be determined, these results suggest that one possible mechanism by which rIFN-gamma may benefit CGD patients is by partially correcting the respiratory burst defect in a subset of monocytes. We conclude that the clinical benefit of prolonged rIFN-gamma therapy in the vast majority of CGD patients is not due to enhanced neutrophil NADPH oxidase activity. The mechanism of action of rIFN-gamma in most CGD patients remains unknown.