Air powder waterjet technology using erythritol or glycine powders in periodontal or peri-implant prophylaxis and therapy: A consensus report of an expert meeting

OBJECTIVES

To attain a collective expert opinion on the use of air powder waterjet technology (APWT) with erythritol and glycine powders in the prophylaxis and therapy of periodontal and peri-implant diseases.

MATERIAL AND METHODS

In the first step, a modified one-round online Delphi survey including 44 five-point Likert scale questions was conducted among a group of 10 expert clinicians and researchers with thorough knowledge and experience in this topic. In the second step, the single questions and the survey results were discussed during a meeting, and consensus statements were formulated, respectively.

RESULTS

An agreement was reached on most items, especially opinions supporting glycine and erythritol powders as favorable with respect to efficiency, safety, and comfort. More scientific evidence is needed to support the improvement in clinical attachment on teeth and implants, especially when APWT with erythritol is used. In addition, APWT needs more long-term evaluation and studies in terms of microbiome/microbiological effects as well as effects on the inflammatory response on natural teeth and implants, also in light of a guided biofilm therapy concept.

CONCLUSIONS

In line with the expert opinions and supported by the evidence, it was concluded that the use of APWT with erythritol and glycine powders in nonsurgical periodontal and peri-implant therapy and prophylaxis is patient compliant and efficient.

957 NKTR-255+cetuximab in patients with solid tumors: interim safety and efficacy results from the phase 1b dose-escalation study

Background

NKTR-255 is an investigational IL-15Rα-dependent, polymer-conjugated, recombinant human IL-15 agonist designed to provide sustained pharmacodynamic (PD) responses without the need for daily dosing. NKTR-255 engages all IL-15 receptor binding complexes to expand, proliferate and activate natural killer (NK) and CD8+ T-cells. This Phase 1b/2 trial (NCT04616196) evaluates NKTR-255+cetuximab in highly refractory patients with head-and-neck squamous cell carcinoma (HNSCC) or colorectal cancer (CRC).

Methods

Successive cohorts received escalating doses of NKTR-255 (q3w) +cetuximab (250mg/m< sup >2</sup > weekly), 1 week after a loading dose of cetuximab alone. Safety (CTCAEv5.0; MTD/recommended Phase 2 dose [RP2D]) and efficacy (RECISTv1.1) were measured. PK/PD analyses were conducted, including assessment by flow cytometry/plasma cytokine analysis. Fold-change was calculated as treatment over baseline for NKTR-255 (baseline=1).

Results

As of August 15, 2021, 12 patients had received ≥1 dose of NKTR-255+cetuximab; (37–70 years; 92% male; HNSCC n=4, CRC n=8; NKTR-255 1.5µg/kg n=7, NKTR-255 3.0µg/kg n=5). Patients had received a median 3.5 lines of prior therapy for metastatic disease. 11 patients had no response to the most recent prior therapy. Of the 12 patients, seven remain on treatment, with five not yet reaching first scan. RP2D has not yet been reached; dose escalation is ongoing.

10 patients experienced an AE; one G5 AE occurred (due to progression). Seven patients reported NKTR-255-related AEs (all G1-2, except one G3 [which resolved in 24 hours]). Any-cause AEs in ≥20% were acneiform dermatitis, fatigue, and infusion-related reaction.

Treatment-induced transient changes in inflammatory cytokines, including IFNy, MCP-1 and IL-6, at 1.5µg/kg (n=3) peaked 4 hours post-infusion and resolved by 24-48 hours. Mean T1/2 of NKTR-255 (1.5µg/kg dose, first cycle) was 27.8 hours.

Dose-dependent expansion of NK and CD8+ T-cells was observed in peripheral blood. For NK cells, mean peak fold-change was ~4-fold and ~6-fold, and for CD8+ T-cells was ~2-fold and ~3-fold (1.5µg/kg and 3µg/kg dose levels, respectively). NK and CD8+ T-cells demonstrated increased Ki67+ proliferative ability.

As of August 15, four patients in the 1.5µg/kg NKTR-255 dose cohort were response-evaluable: one CRC patient (4 prior metastatic treatment lines) reported a confirmed PR (–52%) after 3 cycles; two HNSCC patients reported SD.

Conclusions

NKTR-255 was biologically active and led to expansion and proliferation of NK and CD8+ T-cells. Early dose-escalation data suggest that NKTR-255+cetuximab is safe and tolerable with preliminary anti-tumor activity. Updated data will be presented. NKTR-255, alone and in combination with daratumumab and rituximab, is also being evaluated in liquid tumors.

Acknowledgements

The authors thank the patients and their families involved in the trial.

Trial Registration

NCT04616196

Ethics Approval

The study was approved by site IRBs.

Consent

N/A

Twin boundary migration mechanisms in quasi-statically compressed and plate-impacted Mg single crystals

Twinning is a prominent deformation mode that accommodates plasticity in many materials. This study elucidates the role of deformation rate on the atomic-scale mechanisms that govern twin boundary migration. Examination of Mg single crystals deformed under quasi-static compression was compared with crystals deformed via plate impact. Evidence of two mechanisms was uncovered. Atomic-level observations using high-resolution transmission electron microscopy revealed that twin boundaries in the <a>-axis quasi-statically compressed single crystals are relatively smooth. At these modest stresses and rates, the twin boundaries were found to migrate predominantly via shear (i.e., disconnection nucleation and propagation). By contrast, in the plate-impacted crystals, which are subjected to higher stresses and rates, twin boundary migration was facilitated by local atomic shuffling and rearrangement, resulting in rumpled twin boundaries. This rate dependency also leads to marked variations in twin variant, size, and number density in Mg. Analogous effects are anticipated in other hexagonal closed-packed crystals.

NKTR-358: A novel regulatory T-cell stimulator that selectively stimulates expansion and suppressive function of regulatory T cells for the treatment of autoimmune and inflammatory diseases

Impaired interleukin-2 (IL-2) production and regulatory T-cell dysfunction have been implicated as immunological mechanisms central to the pathogenesis of multiple autoimmune and inflammatory diseases. NKTR-358, a novel regulatory T-cell stimulator, is an investigational therapeutic that selectively restores regulatory T-cell homeostasis in these diseases. We investigated NKTR-358's selectivity for regulatory T-cells, receptor-binding properties, ex vivo and in vivo pharmacodynamics, ability to suppress conventional T-cell proliferation in mice and non-human primates, and functional activity in a murine model of systemic lupus erythematosus. In vitro, NKTR-358 demonstrated decreased affinity for IL-2Rα, IL-2Rβ, and IL-2Rαβ compared with recombinant human IL-2 (rhIL-2). A single dose of NKTR-358 in cynomolgus monkeys produced a greater than 15-fold increase in regulatory T-cells, and the increase lasted until day 14, while daily rhIL-2 administration for 5 days only elicited a 3-fold increase, which lasted until day 7. Repeated dosing of NKTR-358 over 6 months in cynomolgus monkeys elicited cyclical, robust increases in regulatory T-cells with no loss in drug activity over the course of treatment. Regulatory T-cells isolated from NKTR-358-treated mice displayed a sustained, higher suppression of conventional T-cell proliferation than regulatory T-cells isolated from vehicle-treated mice. NKTR-358 treatment in a mouse model (MRL/MpJ-Fas^lpr) of systemic lupus erythematosus for 12 weeks maintained elevated regulatory T-cells for the treatment duration and ameliorated disease progression. Together, these results suggest that NKTR-358 has the ability to elicit sustained and preferential proliferation and activation of regulatory T-cells without corresponding effects on conventional T-cells, with improved pharmacokinetics compared with rhIL-2.

•

NKTR-358 is a pegylated IL-2 designed to induce Treg activation and proliferation.

•

This preclinical study compared NKTR-358 vs recombinant IL-2 for effects on Tregs.

•

NKTR-358 induced a greater increase in Treg:CD8+ T cell ratio compared with rhIL-2.

THU0054 NKTR-358, A NOVEL IL-2 CONJUGATE, STIMULATES HIGH LEVELS OF REGULATORY T CELLS IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS

Background:

Impaired IL-2 production and dysfunction of regulatory T cells (Tregs) have been identified as key immunological defects leading to the breakdown of immune self-tolerance in SLE. Low-dose IL-2 can expand Tregs, but the effect is limited by a narrow therapeutic window for Treg selectivity. Furthermore, the short half-life of IL-2 necessitates frequent administration. NKTR-358 is a polyethylene glycol (PEG) conjugate of recombinant human IL-2 (aldesleukin sequence) and is differentiated from native IL-2 by its altered binding to the IL-2 receptor and prolonged biological activity. NKTR-358 resulted in marked and selective stimulation of Tregs when administered as a single SC injection to healthy volunteers.

Objectives:

This multiple ascending dose study assessed the safety, tolerability, pharmacokinetics (PK), and immune effects of NKTR-358 in patients with SLE after repeated administration of SC doses. The time course and extent of changes in numbers and percentages of Tregs, conventional CD4+ and CD8+ T cells, NK cells, and cytokine levels in peripheral blood were investigated.

Methods:

In this double-blind, multiple ascending dose study, patients with mild to moderate SLE received 3 SC doses q2w in 4 cohorts ranging from 3.0 to 24.0 µg/kg (9 active:3 placebo per cohort); patients were followed for a total of 79 days.

Results:

There were no dose-limiting toxicities, deaths, or clinically significant abnormalities in either vital signs or electrocardiograms. Adverse events attributed to NKTR-358 were primarily limited to mild (grade 1) injection site reactions. At the highest dose, one subject had transient and mild (grade 1) symptoms of a flu-like syndrome after administration, without associated elevated cytokine levels, and another subject had dosing stopped due to elevated eosinophil levels. No other individual at any dose level had systemic signs or symptoms known to be associated with IL-2 therapy. No anti-drug antibodies were detected. NKTR-358 demonstrated dose-proportional PK with repeated dosing; plasma levels peaked 3-6 days post-dose and declined with a terminal half-life of ~10-13 days.

The primary and consistent effect of NKTR-358 was seen on Tregs. In the four dose cohorts, dose-dependent and sustained increases in absolute numbers and percentages of circulating CD4+FoxP3+CD25brightTregs were observed. Treg levels remained elevated throughout the dosing period, peaking at Day 10 after the first administration of NKTR-358 and returning to baseline ~ 20-30 days following last administration. At 24.0 µg/kg, the mean peak increase in numbers of CD25brightTregs was 11-fold above baseline. In addition, there was an increase in Treg activation markers at doses ≥12.0 µg/kg. In contrast to effects on Tregs, no changes in percentages or numbers of conventional CD4+ or CD8+ T cells were observed at any dose tested. At the highest dose, there were low-level increases in the percentages and numbers of NK cells. Overall, NKTR-358 selectively induced Tregs, evidenced by a 12-fold increase in the mean peak Treg:CD8 ratio over baseline in the 24.0 µg/kg group.

Conclusion:

NKTR-358, an IL-2 conjugate Treg stimulator, was well tolerated when repeatedly administered (q2w) at doses up to 24 µg/kg. Its administration led to marked, selective, prolonged, and dose-dependent increases in circulating CD25brightTregs. This clinical study in SLE patients extends the previous results in healthy volunteers and provides strong support for continued testing of NKTR-358 as a new therapeutic in SLE and other inflammatory diseases.

Disclosure of Interests:

Suresh Siddhanti Shareholder of: Nektar Therapeutics, Employee of: Nektar Therapeutics, Christie Fanton Shareholder of: Nektar Therapeutics, Employee of: Nektar Therapeutics, Neha Dixit Shareholder of: Nektar Therapeutics, Employee of: Nektar Therapeutics, Lin Lu Shareholder of: Nektar Therapeutics, Employee of: Nektar Therapeutics, Vishala Chindalore Grant/research support from: Nektar Therapeutics for conducted studies, Speakers bureau: > 5 years ago, Robert Levin Grant/research support from: Payments for clinical research for industry-sponsored trials, Consultant of: Gilead, Exagen, Myriad Rheumatology, Speakers bureau: Sanofi/Genzyme, Regeneron, Bristol-Myers Squibb, AbbVie, Isam Diab: None declared, Richard Furie Grant/research support from: Nektar Therapeutics to Northwell Rheumatology to conduct this study, Consultant of: Nektar Therapeutics, Jonathan Zalevsky Shareholder of: Nektar Therapeutics, Employee of: Nektar Therapeutics, Brian Kotzin Shareholder of: Nektar Therapeutics, Employee of: Nektar Therapeutics

Baseline T cell dysfunction by single cell network profiling in metastatic breast cancer patients

Background

We previously reported the results of a multicentric prospective randomized trial of chemo-refractory metastatic breast cancer patients testing the efficacy of two doses of TGFβ blockade during radiotherapy. Despite a lack of objective responses to the combination, patients who received a higher dose of TGFβ blocking antibody fresolimumab had a better overall survival when compared to those assigned to lower dose (hazard ratio of 2.73, p = 0.039). They also demonstrated an improved peripheral blood mononuclear cell (PBMC) counts and increase in the CD8 central memory pool. We performed additional analysis on residual PBMC using single cell network profiling (SCNP).

Methods

The original trial randomized metastatic breast cancer patients to either 1 or 10 mg/kg of fresolimumab, every 3 weeks for 5 cycles, combined with radiotherapy to a metastatic site at week 1 and 7 (22.5 Gy given in 3 doses of 7.5 Gy). Trial immune monitoring results were previously reported. In 15 patients with available residual blood samples, additional functional studies were performed, and compared with data obtained in parallel from seven healthy female donors (HD): SCNP was applied to analyze T cell receptor (TCR) modulated signaling via CD3 and CD28 crosslinking and measurement of evoked phosphorylation of AKT and ERK in CD4 and CD8 T cell subsets defined by PD-1 expression.

Results

At baseline, a significantly higher level of expression (p < 0.05) of PD-L1 was identified in patient monocytes compared to HD. TCR modulation revealed dysfunction of circulating T-cells in patient baseline samples as compared to HD, and this was more pronounced in PD-1⁺ cells. Treatment with radiotherapy and fresolimumab did not resolve this dyfunctional signaling. However, in vitro PD-1 blockade enhanced TCR signaling in patient PD-1⁺ T cells and not in PD-1^- T cells or in PD-1⁺ T cells from HD.

Conclusions

Functional T cell analysis suggests that baseline T cell functionality is hampered in metastatic breast cancer patients, at least in part mediated by the PD-1 signaling pathway. These preliminary data support the rationale for investigating the possible beneficial effects of adding PD-1 blockade to improve responses to TGFβ blockade and radiotherapy.

Trial registration

NCT01401062.

Abstract 3265: NKTR-255, a polymer-conjugated IL-15 enhances anti-tumor NK cell responses and synergizes with monoclonal antibodies to provide long-term survival in human lymphoma model

Background: IL-15 is a cytokine that activates and provides survival benefit to NK cells. Exploiting the therapeutic value of native IL-15 has been challenging due to its unfavorable pharmacokinetic properties and tolerability. NKTR-255 is a polymer-conjugated human IL-15 that retains binding affinity to the alpha subunit of IL-15 receptor and exhibits reduced clearance to thereby provide a sustained pharmacodynamics response. NKTR-255 has potential for providing an enhanced immunotherapeutic effect when combined with monoclonal antibodies that mediate tumor killing by antibody dependent cellular cytotoxicity (ADCC). Here we investigate the pharmacological properties of NKTR-255 on NK cells and the therapeutic effect of NKTR-255 when combined with tumor-directed monoclonal antibodies in a B cell lymphoma model.

Methods: KHYG-1 cells (human NK cell line) were used to measure phosphorylated STAT5 (pSTAT5) and cell proliferation. Human PBMCs were stimulated with NKTR-255 and/or daratumumab for in vitro NK cell characterization. In the cytotoxic assay, mice received single IV doses of 0.3 mg/kg of NKTR-255 and splenic NK cells were co-cultured with YAC-1 cells (mouse T lymphoma cell line) to measure cytotoxic function. In the Daudi lymphoma model, 1x107 Daudi cells were inoculated IV on Day 0. NKTR-255 (0.03, 0.1 or 0.3 mg/kg SC) was administered on Days 14, 21 and 28 and antibody treatment was administered on Day 14 (daratumumab 0.5 mg/kg IP) or on Days 14 and 17 (rituximab 40 mg/kg IP). Survival rate was determined by onset of hindlimb paralysis as a surrogate parameter.

Results: NKTR-255 dose-dependently induced pSTAT5 and proliferation in KHYG-1 cells (EC50 values for pSTAT5: 0.2 ng/ml, proliferation: 5 ng/ml). NKTR-255 also resulted in enhanced pSTAT5 and NKG2D surface expression on human primary NK cells. In addition NKTR-255 increased NK cell degranulation in co-culture experiments with U266 cells (myeloma cell line) with/without daratumumab (anti-human CD38 antibody), as determined by enhanced CD107a surface expression. In vivo pretreatment with NKTR-255 resulted in sustained cytotoxic function of NK cells in both ex vivo and in vivo studies. Finally, NKTR-255 synergistically provided long-term survival benefit in a dose-dependent manner when administered with daratumumab or rituximab (anti-human CD20 antibody) in the Daudi B cell lymphoma model.

Conclusions: NKTR-255 is an immune stimulator of NK cells that provides a dose-dependent effect in the proliferation and activation of NK cells. This property of NKTR-255, when administered with daratumumab or rituximab, translates into enhanced therapeutic efficacies of the antibodies in a B cell lymphoma model. These results indicate that combining NKTR-255 with a tumor-directed antibody having an ADCC mechanism can provide a synergistic effect for treating cancers.

Citation Format: Takahiro Miyazaki, Saul Kivimäe, Rhoneil Pena, Peiwen Kuo, Marlene Hennessy, Murali Addepalli, Neha Dixit, Wildaliz Nieves, Sara Sheibani, Mekhala Maiti, Laurie VanderVeen, Joanna Wilczek, Loui Madakamutil, Jonathan Zalevsky. NKTR-255, a polymer-conjugated IL-15 enhances anti-tumor NK cell responses and synergizes with monoclonal antibodies to provide long-term survival in human lymphoma model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3265.

Treatment data and technical process challenges for practical big data efforts in radiation oncology

The term Big Data has come to encompass a number of concepts and uses within medicine. This paper lays out the relevance and application of large collections of data in the radiation oncology community. We describe the potential importance and uses in clinical practice. The important concepts are then described and how they have been or could be implemented are discussed. Impediments to progress in the collection and use of sufficient quantities of data are also described. Finally, recommendations for how the community can move forward to achieve the potential of big data in radiation oncology are provided.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Abstract 4987: Role of the PD-1/PDL-1 pathway in resistance of patients with metastatic breast cancer to treatment with radiotherapy and TGFβ neutralization

Experimental data and clinical observations indicate that local radiation therapy (RT) converts the irradiated tumor into an in situ vaccine and improves responses to immunotherapy. Preclinical breast cancer models show that TGFb neutralization was required to achieve CD8+ T cell priming specific for multiple tumor antigens, and rejection of the irradiated tumor and non-irradiated metastases (Vanpouille-Box et al., Cancer Res 2015). Tumor response and survival were improved by PD-1 blockade. We explored the role of the PD-1/PDL-1 pathway in resistance to combined RT + TGFβ neutralizing antibody (fresolimumab) in metastatic breast cancer patients (pts).

22 pts were treated in a prospective trial at NYU and UCLA (NCT01401062, supported by DOD MTA BC100481). Pts were randomly assigned to 2 doses of fresolimumab (freso) (1mg/kg and 10 mg/kg, q 3 weeks). Image guided RT was delivered to one metastasis on weeks 2 and 7, 7.5 GyX3. 1 pt achieved objective response, with 28% reduction of tumor burden. The response lasted 11 months, anthracycline-induced acute myelogenous leukemia developed. Pts randomized to the higher freso dose had a hazard ratio of 2.17 (95% CI: 0.753-6.272) for risk of death at 1 year follow up. Currently, at a median follow up of 2 years, 20/22 pts have died.

To explore reasons for the limited response, peripheral blood mononuclear cells collected at baseline, 5 and 15 weeks into treatment, were analyzed. Responses to survivin, as a tumor antigen, were assessed using tetramers. Single cell network profiling (SCNP) was used to evaluate expression of 6 immunomodulatory receptors plus immune signaling in T cells collected from 7 healthy donors (HD) and 15 breast cancer pts (6 at 1mg/kg, 9 at 10mg/kg fresolimumab). In vitro activation of p-AKT and p-Erk was quantified following in vitro T cell receptor (TCR) modulation with anti-CD3/αnti-CD28.

6/12 HLA-A2.1+ pts had pre-existing survivin-specific CD8+ T cells, and 3 showed an increase over time. 2 pts who were negative generated modest responses after RT and 10 mg/kg freso. Prior to treatment, PDL-1 expression was increased in monocytes (p = 0.01) and CD4+ T cells (p = 0.037) compared to HD. Elevated PD-1 (p = 0.054) and OX-40 (p = 0.014) expression were identified on CD4+ T cells of pts. Upon TCR modulation, CD4+ and CD8+ T cells from pts showed reduced signaling through p-AKT and, to a lesser extent, p-Erk, compared to HD. Signaling was lower in PD-1+ vs PD-1- CD8+ and CD4+ T cells. Addition of anti-PD-1 pembrolizumab partially restored TCR-mediated signaling through p-AKT and p-Erk in PD-1+ but not PD-1- T cells.

Overall, data indicate impaired T cell signaling in PD-1+ T cells of metastatic breast cancer pts, which may explain the inability to respond to RT + TGFβ blockade. In vitro addition of anti-PD-1 improved T cell signaling through p-AKT and p-Erk. Together with the preclinical data, this supports adding anti-PD-1 to the combination of RT +TGFβ blockade.

Citation Format: Sandra Demaria, Claire Vanpouille-Box, Rachael E. Hawtin, Christie Fanton, Andy Conroy, Erik Evensen, Neha Dixit, Alan Barber, Dorthe Schaue, William H. McBride, Mary Helen Barcellos-Hoff, Silvia C. Formenti. Role of the PD-1/PDL-1 pathway in resistance of patients with metastatic breast cancer to treatment with radiotherapy and TGFβ neutralization. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4987.

Thioredoxin fusion construct enables high-yield production of soluble, active matrix metalloproteinase-8 (MMP-8) in Escherichia coli

Matrix metalloproteinases (MMPs) are crucial proteases in maintaining the health and integrity of many tissues, however their dysregulation often facilitates disease progression. In disease states these remodeling and repair functions support, for example, metastasis of cancer by both loosening the matrix around tumors to enable cellular invasion and by affecting proliferation and apoptosis, and they promote degradation of biological restorations by weakening the substrate to which the restoration is attached. As such, MMPs are important therapeutic targets. MMP-8 participates in cancer, arthritis, asthma and failure of dental fillings. MMP-8 differs from other MMPs in that it has an insertion that enlarges its active site. To elucidate the unique features of MMP-8 and develop selective inhibitors to this therapeutic target, a stable and active form of the enzyme is needed. MMP-8 has been difficult to express at high yield in a soluble, active form. Typically recombinant MMPs accumulate in inclusion bodies and complex methods are applied to refold and purify protein in acceptable yield. Presented here is a streamlined approach to produce in Escherichia coli a soluble, active, stable MMP-8 fusion protein in high yield. This fusion shows much greater retention of activity when stored refrigerated without glycerol. A variant of this construct that contains the metal binding claMP Tag was also examined to demonstrate the ability to use this tag with a metalloprotein. SDS-PAGE, densitometry, mass spectrometry, circular dichroism spectroscopy and an activity assay were used to analyze the chemical integrity and function of the enzyme.

Infection-induced type I interferons activate CD11b on B-1 cells for subsequent lymph node accumulation

Innate-like B-1a lymphocytes rapidly redistribute to regional mediastinal lymph nodes (MedLNs) during influenza infection to generate protective IgM. Here we demonstrate that influenza infection-induced type I interferons directly stimulate body cavity B-1 cells and are a necessary signal required for B-1 cell accumulation in MedLNs. Vascular mimetic flow chamber studies show that type I interferons increase ligand-mediated B-1 cell adhesion under shear stress by inducing high-affinity conformation shifts of surface-expressed integrins. In vivo trafficking experiments identify CD11b as the non-redundant, interferon-activated integrin required for B-1 cell accumulation in MedLNs. Thus, CD11b on B-1 cells senses infection-induced innate signals and facilitates their rapid sequester into secondary lymphoid tissues, thereby regulating the accumulation of polyreactive IgM producers at sites of infection.

Streptolysin O Rapidly Impairs Neutrophil Oxidative Burst and Antibacterial Responses to Group A Streptococcus

Group A Streptococcus (GAS) causes a wide range of human infections, ranging from simple pharyngitis to life-threatening necrotizing fasciitis and toxic shock syndrome. A globally disseminated clone of M1T1 GAS has been associated with an increase in severe, invasive GAS infections in recent decades. The secreted GAS pore-forming toxin streptolysin O (SLO), which induces eukaryotic cell lysis in a cholesterol-dependent manner, is highly upregulated in the GAS M1T1 clone during bloodstream dissemination. SLO is known to promote GAS resistance to phagocytic clearance by neutrophils, a critical first element of host defense against invasive bacterial infection. Here, we examine the role of SLO in modulating specific neutrophil functions during their early interaction with GAS. We find that SLO at subcytotoxic concentrations and early time points is necessary and sufficient to suppress neutrophil oxidative burst, in a manner reversed by free cholesterol and anti-SLO blocking antibodies. In addition, SLO at subcytotoxic concentrations blocked neutrophil degranulation, interleukin-8 secretion and responsiveness, and elaboration of DNA-based neutrophil extracellular traps, cumulatively supporting a key role for SLO in GAS resistance to immediate neutrophil killing. A non-toxic SLO derivate elicits protective immunity against lethal GAS challenge in a murine infection model. We conclude that SLO exerts a novel cytotoxic-independent function at early stages of invasive infections (<30 min), contributing to GAS escape from neutrophil clearance.

Leukotriene B4 activates intracellular calcium and augments human osteoclastogenesis

Introduction

Bone erosion in inflammatory arthritis depends on the recruitment and activation of bone resorbing cells, the osteoclasts. Interleukin-23 (IL-23) has been primarily implicated in mediating inflammatory bone loss via the differentiation of Th17 receptor activator of nuclear factor κB ligand (RANKL)–producing cells. In this article, we describe a new role of IL-23 in activating the synthesis and production of leukotriene B4 (LTB4) in innate immune cells.

Methods

We utilized whole blood–derived human peripheral blood mononuclear cells (PBMCs), differentiated them towards an osteoclast lineage and then performed immunofluorescence and cytochemical staining to detect the expression of LTB4-associated receptors and enzymes such as phospholipase A2, 5-lipoxygenase and leukotriene A4 hydrolase, as well as the presence of tartrate-resistant acid phosphatase (TRAP) and F-actin rings on fully mature osteoclasts. We used enzyme immunoassays to measure LTB4 levels in culture media derived from IL-23-treated human PBMCs. We used real-time calcium imaging to study the effect of leukotrienes and requirements of different calcium sources and signaling proteins in activating intracellular calcium flux using pharmacological inhibitors to phospholipase C (U73122), membrane calcium channels (2-APB) and phosphatidylinositol 3-kinase (Wortmannin) and utilized qPCR for gene expression analysis in macrophages and osteoclasts.

Results

Our data show that LTB4 engagement of BLT1 and BLT2 receptors on osteoclast precursors leads to activation of phospholipase C and calcium release–activated channel–mediated intracellular calcium flux, which can activate further LTB4 autocrine production. IL-23-induced synthesis and secretion of LTB4 resulted in the upregulation of osteoclast-related genes NFATC1, MMP9, ACP5, CTSK and ITGB3 and the formation of giant, multinucleated TRAP⁺ cells capable of F-actin ring formation. These effects were dependent on Ca²⁺ signaling and were completely inhibited by BLT1/BLT2 and/or PLC and CRAC inhibitors.

Conclusions

In conclusion, IL-23 can initiate osteoclast differentiation independently from the RANK-RANKL pathway by utilizing Ca²⁺ signaling and the LTB4 signaling cascade.

Crosstalk among IL-23 and DNAX activating protein of 12 kDa-dependent pathways promotes osteoclastogenesis

IL-23 has been well studied in the context of T cell differentiation; however, its role in the differentiation of myeloid progenitors is less clear. In this paper, we describe a novel role of IL-23 in myeloid cell differentiation. Specifically, we have identified that in human PBMCs, IL-23 induces the expression of MDL-1, a PU.1 transcriptional target during myeloid differentiation, which orchestrates osteoclast differentiation through activation of DNAX activating protein of 12 kDa and its ITAMs. The molecular events that lead to the differentiation of human macrophages to terminally differentiated osteoclasts are dependent on spleen tyrosine kinase and phospholipase Cγ2 phosphorylation for the induction of intracellular calcium flux and the subsequent activation of master regulator osteoclast transcription factor NFATc1. IL-23-elicited osteoclastogenesis is independent of the receptor activator of NF-κB ligand pathway and uses a unique myeloid DNAX activating protein of 12 kDa-associated lectin-1(+)/DNAX activating protein of 12 kDa(+) cell subset. Our data define a novel pathway that is used by IL-23 in myeloid cells and identify a major mechanism for the stimulation of osteoclastogenesis in inflammatory arthritis.

A novel in vivo gene transfer technique and in vitro cell based assays for the study of bone loss in musculoskeletal disorders

Differentiation and activation of osteoclasts play a key role in the development of musculoskeletal diseases as these cells are primarily involved in bone resorption. Osteoclasts can be generated in vitro from monocyte/macrophage precursor cells in the presence of certain cytokines, which promote survival and differentiation. Here, both in vivo and in vitro techniques are demonstrated, which allow scientists to study different cytokine contributions towards osteoclast differentiation, signaling, and activation. The minicircle DNA delivery gene transfer system provides an alternative method to establish an osteoporosis-related model is particularly useful to study the efficacy of various pharmacological inhibitors in vivo. Similarly, in vitro culturing protocols for producing osteoclasts from human precursor cells in the presence of specific cytokines enables scientists to study osteoclastogenesis in human cells for translational applications. Combined, these techniques have the potential to accelerate drug discovery efforts for osteoclast-specific targeted therapeutics, which may benefit millions of osteoporosis and arthritis patients worldwide.

Detection of bidirectional signaling during integrin activation and neutrophil adhesion

Neutrophil arrest and migration on inflamed endothelium is dependent upon a conformational shift in CD11a/CD18 (LFA-1) from a low to high affinity and clustered state which determines the strength and lifetime of bond formation with intracellular adhesion molecule 1 (ICAM-1). Cytoskeletal adaptor proteins kindlin-3 and talin-1 anchor clustered LFA-1 to the cytoskeleton and support the transition from neutrophil rolling to arrest. We employ microfluidic flow channels and total internal reflection fluorescence microscopy to evaluate the spatiotemporal regulation of LFA-1 affinity and bond formation that facilitate the transition from neutrophil rolling to arrest. Methodology is presented to correlate the relationship between integrin conformation, bond formation with ICAM-1, and cytoskeletal engagement and adhesion strengthening necessary to achieve a migratory phenotype.

Leukocyte function antigen-1, kindlin-3, and calcium flux orchestrate neutrophil recruitment during inflammation

Neutrophil arrest and migration on inflamed endothelium involves a conformational shift in CD11a/CD18 (leukocyte function antigen-1; LFA-1) to a high-affinity and clustered state that determines the strength and lifetime of bond formation with ICAM-1. Cytoskeletal adapter proteins Kindlin-3 and Talin-1 anchor clustered LFA-1 to the cytoskeleton and facilitate the transition from neutrophil rolling to arrest. We recently reported that tensile force acts on LFA-1 bonds inducing their colocalization with Orai1, the predominant membrane store operated Ca(2+) channel that cooperates with the endoplasmic reticulum to elicit cytosolic flux. Because Kindlin-3 was recently reported to initiate LFA-1 clustering in lymphocytes, we hypothesized that it cooperates with Orai1 and LFA-1 in signaling local Ca(2+) flux necessary for shear-resistant neutrophil arrest. Using microfluidic flow channels combined with total internal reflection fluorescence microscopy, we applied defined shear stress to low- or high-affinity LFA-1 and imaged the spatiotemporal regulation of bond formation with Kindlin-3 recruitment and Ca(2+) influx. Orai1 and Kindlin-3 genes were silenced in neutrophil-like HL-60 cells to assess their respective roles in this process. Kindlin-3 was enriched within focal clusters of high-affinity LFA-1, which promoted physical linkage with Orai1. This macromolecular complex functioned to amplify inside-out Ca(2+) signaling in response to IL-8 stimulation by catalyzing an increased density of Talin-1 and consolidating LFA-1 clusters within sites of contact with ICAM-1. In this manner, neutrophils use focal adhesions as mechanosensors that convert shear stress-mediated tensile force into local bursts of Ca(2+) influx that catalyze cytoskeletal engagement and an adhesion-strengthened migratory phenotype.

Chemokines, selectins and intracellular calcium flux: temporal and spatial cues for leukocyte arrest

Leukocyte trafficking to acute sites of injury or infection requires spatial and temporal cues that fine tune precise sites of firm adhesion and guide migration to endothelial junctions where they undergo diapedesis to sites of insult. Many detailed studies on the location and gradient of chemokines such as IL-8 and other CXCR ligands reveal that their recognition shortly after selectin-mediated capture and rolling exerts acute effects on integrin activation and subsequent binding to their ligands on the endothelium, which directs firm adhesion, adhesion strengthening, and downstream migration. In this process, G-protein coupled receptor (GPCR) signaling has been found to play an integral role in activating and mobilizing intracellular stores of calcium, GTPases such as Rap-1 and Rho and cytokeletal proteins such as Talin and F-actin to facilitate cell polarity and directional pseudopod formation. A critical question remaining is how intracellular Ca(2+) flux from CRAC channels such as Orai1 synergizes with cytosolic stores to mediate a rapid flux which is critical to the onset of PMN arrest and polarization. Our review will highlight a specific role for calcium as a signaling messenger in activating focal clusters of integrins bound to the cytoskeleton which allows the cell to attain a migratory phenotype. The precise interplay between chemokines, selectins, and integrins binding under the ubiquitous presence of shear stress from blood flow provides an essential cooperative signaling mechanism for effective leukocyte recruitment.

Future specialization interests among medical students in southern India

BACKGROUND

A consideration of the future specialization interests of undergraduate medical students might help to understand the needs of higher medical education and future manpower availability for healthcare.

METHODS

A cross-sectional study was conducted among 373 undergraduate students of a medical college in southern India using a self-administered questionnaire.

RESULTS

Of the 373 students, 188 (50.4%) were men. Almost all of them (370 [99.2%]) wanted to pursue postgraduation. Of these, 267 (72.4%) wanted to pursue postgraduation in India. Overall, the first choice subject was surgery (120 [32.2%]) followed by internal medicine (85 [22.8%]) and paediatrics (43 [11.5%]). The third preference for men and women differed, with men choosing orthopaedics and women choosing obstetrics and gynaecology. The factors that influenced the choice of specialization were interest in the speciality (Likert scale score 4.7), job satisfaction (4.6), employment opportunities (4.0), job security (4) and high income potential (3.9).

CONCLUSION

It was evident from the proportion of students desiring to do postgraduation and their choice of specialties that most of them will end up working at hospitals instead of at primary healthcare centres. The deficiencies of certain specialists such as ophthalmologists are likely to persist. This is a cause for concern as the majority of our population lives in rural areas and there is already a maldistribution of doctors.

Migrational guidance of neutrophils is mechanotransduced via high-affinity LFA-1 and calcium flux

Acute inflammation triggers the innate immune response of neutrophils that efficiently traffic from the bloodstream to concentrate at high numbers at the site of tissue infection or wounding. A gatekeeper in this process is activation of β(2) integrins, which form bond clusters with ICAM-1 on the endothelial surface. These bond clusters serve dual functions of providing adhesive strength to anchor neutrophils under the shear forces of blood flow and directional guidance for cell polarization and subsequent transmigration on inflamed endothelium. We hypothesized that shear forces transmitted through high-affinity LFA-1 facilitates the cooperation with the calcium release-activated channel Orai1 in directing localized cytoskeletal activation and directed migration. By using vascular mimetic microfluidic channels, we observed neutrophil arrest on a substrate of either ICAM-1 or allosteric Abs that stabilize a high- or low-affinity conformation of LFA-1. Neutrophils captured via low-affinity LFA-1 did not exhibit intracellular calcium flux, F-actin polymerization, cell polarization, or directional migration under shear flow. In contrast, high-affinity LFA-1 provided orientation along a uropod-pseudopod axis that required calcium flux through Orai1. We demonstrate how the shear stress of blood flow can transduce distinct outside-in signals at focal sites of high-affinity LFA-1 that provide contact-mediated guidance for neutrophil emigration.

Shear forces and high affinity LFA-1 drive PMN recruitment (102.18)

Acute inflammation triggers the innate immune response of neutrophils that efficiently traffic from the blood stream to concentrate at high numbers at the site of tissue infection or wounding. A gatekeeper in this process is activation of β2-integrins, which forms bond clusters with ICAM-1 on the endothelial surface. These bond clusters serve dual functions of providing adhesive strength to anchor neutrophils under the shear forces of blood flow and directional guidance for cell polarization and subsequent transmigration on inflamed endothelium. We hypothesized that shear forces transmitted through high affinity LFA-1 facilitates their cooperation with the calcium release activated channel (CRAC) Orai1 in directing localized cytoskeletal activation and directed migration. Employing vascular mimetic microfluidic channels we observed neutrophils arresting on a substrate of either ICAM-1 or allosteric antibodies that stabilize a high or low affinity conformation of LFA-1. Neutrophils captured via low affinity LFA-1 did not exhibit intracellular calcium flux, F-actin polymerization, cell polarization, or directional migration under shear flow. In contrast, high affinity LFA-1 provided orientation along a uropod-pseudopod axis that required calcium flux through Orai1. We demonstrate how the shear stress of blood flow can transduce distinct outside-in signals at focal sites of high affinity LFA-1 that provides contact mediated guidance for neutrophil emigration.

The LFA-1/ICAM-1 bond: A Spatio-Temporal Cue in PMN Recruitment in Acute Inflammation (140.3)

Polymorphonuclear leukocyte (PMN) adhesion to the inflamed endothelium is in part mediated by LFA-1(CD11a/CD18) which recognizes its ligand ICAM-1. It has long been known that ICAM-1 rapidly forms homodimers and this conformation supports stable bonds specifically with high affinity LFA-1 on the PMN in the presence of shear flow. We hypothesize that shear stress on these dimeric pairs of bonds between high affinity LFA-1 and ICAM-1 result in intracellular signaling that serves as a gatekeeper in the transition from PMN arrest to a migratory phenotype. Imaging PMN rolling on an inflammatory mimetic substrate expressing allosteric activating and blocking antibodies to CD18 under shear flow revealed that calcium flux as well as Talin recruitment was mediated primarily through shear stress acting on high affinity CD18 bonds. Immunofluorescence revealed colocalization of cytoplasmic F-actin, Talin, Rap-1, and phospho-Src within regions correlating with high affinity clusters of LFA-1. In summary, these data sets reveal that an integrin mediated outside-in signal is dependent on shear and the affinity of LFA-1 for its ligand ICAM-1 and that a minimum dimerization of high affinity LFA-1/ICAM-1 bonds elicits the assembly of a macromolecular complex that provides a key navigational step in the transition from PMN arrest to a migratory phenotype.

Transmigration of neutrophils across inflamed endothelium is signaled through LFA-1 and Src family kinase

Leukocyte capture on inflamed endothelium is facilitated by a shift in LFA-1 from low to high affinity that supports binding to ICAM-1. LFA-1 bonds help anchor polymorphonuclear leukocytes (PMN) to inflamed endothelium in shear flow, and their redistribution to the leading edge guides pseudopod formation, migration, and extravasation. These events can be disrupted at the plasma membrane by stabilizing LFA-1 in a low- or intermediate-affinity state with allosteric small molecules. We hypothesized that a minimum dimeric bond formation between high-affinity LFA-1 and ICAM-1 under shear stress is necessary to catalyze transmembrane signaling of directed cell migration. Microspheres and substrates were derivatized with monomeric or dimeric ICAM-1 to simulate the surface of inflamed endothelium under defined ligand valence. Binding to dimeric ICAM-1, and not monomeric ICAM-1, was sufficient to elicit assembly of F-actin and phosphorylation of Src family kinases that colocalized with LFA-1 on adherent PMN. Genetic deletion or small molecule inhibition of Src family kinases disrupted their association with LFA-1 that correlated with diminished polarization of arrested PMN and abrogation of transmigration on inflamed endothelium. We conclude that dimeric bond clusters of LFA-1/ICAM-1 provide a key outside-in signal for orienting cytoskeletal dynamics that direct PMN extravasation at sites of inflammation.

Healthcare utilization among veterans undergoing chemotherapy: the impact of a cancer care coordination/home-telehealth program

The 2001 Institute of Medicine report indicted that the US healthcare system fails to provide high-quality care, and offered 6 aims of improvement that would redesign the delivery of care for the 21st century. This study compared the use of Department of Veterans Affairs (VA) inpatient and outpatient services of cancer patients enrolled in a Cancer Care Coordination/Home-Telehealth (CCHT) program that involved remote management of symptoms (eg, emotional distress, pain) via home-telehealth technologies to a control group of cancer patients receiving standard VA care. Using a matched case-control design, 2 control patients per case were selected, matched by tumor type and cancer stage. There were 43 Cancer CCHT patients and 82 control group patients. Based on a medical record review of each patient, the total number of cancer-related services (defined as visits that were expected given the patients' cancer diagnosis and treatment protocol) and preventable services (defined as visits needed outside of those expected given the cancer diagnosis and planned treatment) were calculated over a 6-month period. Poisson multivariate regression models were used to estimate the adjusted relative risks (RRs) for the effects of the Cancer CCHT program on the service use outcomes. Cancer CCHT patients had significantly fewer preventable services (clinic visits: RR = 0.03, 95% confidence interval [CI] = 0.00-0.24; bed days of care (BDOC) for hospitalization [all-cause]: RR = 0.50, 95% CI = 0.37-0.67; hospitalizations [chemotherapy related]: RR = 0.43, 95% CI = 0.21-0.91; and BDOC for hospitalizations [chemotherapy related]: RR = 0.49, 95% CI = 0.34-0.71) than the control group. This study offered some preliminary evidence that patients enrolled in a Cancer CCHT program can successfully manage multiple complex symptoms without utilizing inpatient and outpatient services.

Development and evaluation of a microemulsion formulation for transdermal delivery of terbinafine

The aim of the present study is to develop and evaluate microemulsion formulations for Terbinafine (TB) with a view to enhance its permeability through the skin and provide release for 24 h. Various o/w microemulsions were prepared by the spontaneous emulsification method. Oleic acid was chosen as the oil phase, Caprylo caproyl macrogol-8- glyceride (Labrasol S) and purified diethylene glycol monoethyl ether (Transcutol P) were used as surfactant and cosurfactant, respectively, on the basis of solubility studies. Pseudoternary phase diagrams were constructed to obtain the concentration range of oil, surfactant, cosurfactant, and water for microemulsion formulation. The optimized microemulsion consisted of 2% w/w TB, 8% w/w oleic acid, 31% w/w labrasol S, 31% w/w transcutol P, and 30% w/w distilled water. Permeability parameters like Jss and Kp were found to be significantly higher for formulation F4 as compared to other formulations (P < 0.05). Microbiological studies of TB in microemulsion showed better anti-fungal activity against Candida albicans and Aspergillus flavus as compared to marketed product (P < 0.05).

The role of ACE gene polymorphism in rapidity of progression of focal segmental glomerulosclerosis

BACKGROUND

The insertion/deletion (I/D) polymorphism of angiotensin converting enzyme (ACE) gene has been associated with progression of renal diseases.

AIMS

We investigated its role in the rate of progression of focal segmental glomerulosclerosis (FSGS).

METHODS

Forty-seven patients with end-stage renal disease (ESRD) due to FSGS were evaluated.

RESULTS

The distribution of ACE genotype was II-25.5%, ID-55.5%, and DD-19%, as compared to 40 controls with genotype of 7.5%, 60%, and 32.5%, respectively (p= NS). In African Americans (AA) the gene frequencies among patients and controls were I-43%, D-57% vs I-36%, D-64%, respectively. This was different than the gene frequencies in White/Hispanic (W/H) patients I-61.5%, D-38.5% vs I-38.6%, D-61.4%, in controls (P < 0.05). In 22 patients with rapid progression (RP) of FSGS to ESRD the genotype distribution was II-18%, ID -64%, and DD-18%. In 25 patients with FSGS who progressed slowly (SP) the genotype was similar (II-32%, ID-48% and DD-20%, P >0.05). With respect to rate of progression, D allele frequency was similar in AA patients (RP 64% vs SP 50%) and W/H patients (RP 36% vs SP 40%).

CONCLUSION

Our study reveals no association between the I/D polymorphism of the ACE gene and the presence of and rapidity progression of FSGS.

Genotyping of CYP21, linked chromosome 6p markers, and a sex-specific gene in neonatal screening for congenital adrenal hyperplasia

We investigated the feasibility and diagnostic utility of genotyping 9 CYP21 mutations, linked chromosome 6p markers, and a dimorphic X-Y marker from neonatal screening samples. Blood-impregnated filter papers (Guthrie cards) from 603 randomly chosen New Zealand neonates were genotyped blind to 17-hydroxyprogesterone (17-OHP) levels. Another 50 samples from Swiss and North American infants with correlative hormonal data were also genotyped. DNA was extracted, and gene-specific PCR was performed. CYP21 PCR products were subjected to ligase detection reaction, simultaneously analyzing 9 CYP21 mutations; PCR products of other genes were subjected to direct gel analysis. CYP21 genotyping indicated a heterozygote rate of 2.8% for classic mutations (excluding CYP21 deletions), and 2.0% for nonclassic mutations in New Zealanders. Ten full-term affected neonates showed a wide range of 17-OHP levels (15-1400 nmol/L). Sick or preterm infants or infants screened on the first day of life with high 17-OHP proved genetically unaffected. Genetic linkage disequilibrium was found between two CYP21 mutations and chromosome 6p markers. Guthrie cards can be used to accurately genotype CYP21 and other relevant markers, potentially enhancing the specificity and sensitivity of congenital adrenal hyperplasia screening. CYP21 heterozygote frequency for classic mutations is higher than expected based on genotype compared with that predicted by hormonal newborn screening.

Study of a kindred with classic congenital adrenal hyperplasia: diagnostic challenge due to phenotypic variance

We sought to determine the concordance of the phenotype and genotype in a kindred with classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency. The variation in phenotypic expression within this family underscores the difficulty of establishing the diagnosis in the absence of newborn screening, even with a heightened index of suspicion. Steroidogenic profiles were obtained for the three affected siblings. The available clinical history of the two affected aunts was retrieved. Genotyping was performed on several members of the kindred. Detailed sequencing of the entire CYP21 gene of two clinically dissimilar subjects in this family was undertaken to explore the possibility of other mutations or polymorphisms. PCR with ligase detection reaction analysis of CYP21 revealed that the affected family members III-2, III-3, III-4, II-3, and II-4, all were compound heterozygotes carrying the intron 2 point mutation known to interfere with splicing (nucleotide 656 A to G) and the exon 4 point mutation causing a nonconservative substitution of asparagine for isoleucine at codon 172 (I172N). Detailed sequencing of the gene was performed for the two most phenotypically dissimilar subjects. A single silent polymorphism was found in the third nucleotide for codon 248 in patient II-4, but not in patient III-4, and no additional mutations were found. Classic congenital adrenal hyperplasia remains a difficult diagnosis to make in the absence of newborn screening because of the variability of phenotypic expression. Likewise, the variable degree of genital ambiguity in affected females in this family serves to question universal advocacy of prenatal steroid treatment in pregnancies at risk for congenital adrenal hyperplasia. Extensive molecular exploration did not provide an explanation of the phenotypic heterogeneity and supports the possibility of influences other than the CYP21 gene for the observed divergence.

Steroid 21-hydroxylase expression and activity in human lymphocytes

Steroid 21-hydroxylase encoded by CYP21 is expressed in adrenal cortex. Mutations in CYP21 cause potentially lethal congenital adrenal hyperplasia (CAH). Earlier observations suggested alternative sources of 21-hydroxylase activity, although its genetic source remains unclear. We found a novel source of CYP21 expression in normal human cultured B lymphocytes. The quantity of 21-hydroxylase transcript was reduced in B cell lines of CAH subjects compared with that in normal B-lymphoblastoid cells. No CYP21 transcript was detected in lymphocytes from a CAH patient with homozygous CYP21 deletion. Cultured lymphoid cells, including those carrying homozygous CYP21 deletion, and peripheral blood leukocytes converted both 17-hydroxyprogesterone to 11-deoxycortisol and progesterone to deoxycorticosterone. We conclude that lymphocytes express CYP21, but also possess a 21-hydroxylase distinct from CYP21. Activity of this isozyme may partially compensate for severe adrenal 21-hydroxylase deficiency.