Relationship of anifrolumab pharmacokinetics with efficacy and safety in patients with systemic lupus erythematosus

OBJECTIVES

To characterize the relationship of anifrolumab pharmacokinetics with efficacy and safety in patients with moderate to severe SLE despite standard therapy, using pooled data from two phase 3 trials.

METHODS

TULIP-1 and TULIP-2 were randomized, placebo-controlled, 52-week trials of intravenous anifrolumab (every 4 weeks for 48 weeks). For the exposure-response analysis, BILAG-based Composite Lupus Assessment (BICLA) or SLE Responder Index [SRI(4)] response rates at week 52 in each quartile/tertile of average anifrolumab serum concentration (Cave) were compared for anifrolumab and placebo in all-comers, patients who completed treatment, and IFN gene signature (IFNGS)-high patients who completed treatment, using average marginal effect logistic regression. Relationships between exposure and key safety events were assessed graphically.

RESULTS

Of patients in TULIP-1/TULIP-2 who received anifrolumab (150 mg, n = 91; 300 mg, n = 356) or placebo (n = 366), 574 completed treatment, of whom 470 were IFNGS high. In the exposure-efficacy analyses, BICLA and SRI(4) treatment differences favouring anifrolumab 300 mg vs placebo were observed across Cave subgroups and all analysis populations. Logistic regression identified Cave as a significant covariate for predicted BICLA response, as higher anifrolumab Cave predicted greater efficacy. There was no evidence of exposure-driven incidence of key safety events through week 52 in patients receiving anifrolumab 150 or 300 mg.

CONCLUSION

While higher Cave predicted greater efficacy, consistent positive benefit favouring anifrolumab 300 mg vs placebo was observed in BICLA and SRI(4) responses across Cave subgroups in the TULIP trials. There was no evidence of exposure-driven safety events.

CLINICALTRIAL.GOV NUMBERS

NCT02446912, NCT02446899.

The Relationship between Anifrolumab Pharmacokinetics, Pharmacodynamics, and Efficacy in Patients With Moderate to Severe Systemic Lupus Erythematosus

This study aimed to elucidate the pharmacokinetic/pharmacodynamic and pharmacodynamic/efficacy relationships of anifrolumab, a type I interferon receptor antibody, in patients with moderate to severe systemic lupus erythematosus. Data were pooled from the randomized, 52‐week, placebo‐controlled TULIP‐1 and TULIP‐2 trials of intravenous anifrolumab (150 mg/300 mg, every 4 weeks for 48 weeks). Pharmacodynamic neutralization was measured with a 21‐gene type I interferon gene signature (21‐IFNGS) in patients with high IFNGS. The pharmacokinetic/pharmacodynamic relationship was analyzed graphically and modeled with a nonlinear mixed‐effects model. British Isles Lupus Assessment Group–based Composite Lupus Assessment (BICLA) response rates were compared across 21‐IFNGS neutralization quartiles. Overall, 819 patients received ≥1 dose of anifrolumab or placebo, of whom 676 were IFNGS high. Over 52 weeks, higher average anifrolumab serum concentrations were associated with increased median 21‐IFNGS neutralization, which was rapid and sustained with anifrolumab 300 mg (>80%, weeks 12‐52), lower and delayed with anifrolumab 150 mg (>50%, week 52), and minimal with placebo. The proportion of patients with week 24 anifrolumab trough concentration exceeding the IC₈₀ (3.88 μg/mL) was greater with anifrolumab 300 mg vs anifrolumab 150 mg (≈83% vs ≈27%), owing to the higher estimated median trough concentration (15.6 vs 0.2 μg/mL). BICLA response rates increased with 21‐IFNGS neutralization; more patients had a BICLA response in the highest vs lowest neutralization quartiles at week 52 (58.1% vs 37.6%). In conclusion, anifrolumab 300 mg every 4 weeks rapidly, substantially, and sustainably neutralized the 21‐IFNGS and was associated with clinical efficacy, supporting this dosing regimen in patients with systemic lupus erythematosus.

POS0688 CHARACTERIZATION OF PK/PD OF ANIFROLUMAB IN PATIENTS WITH MODERATE TO SEVERE SLE

Background:

In the TULIP-1 and TULIP-2 trials, anifrolumab, a type I interferon (IFN) receptor antibody, at a dosage of 300 mg once every 4 weeks (Q4W), demonstrated consistent median pharmacokinetic (PK) concentrations1 and sustained neutralization of the pharmacodynamic (PD) 21-gene type I IFN gene signature (IFNGS)2–4 in patients with moderate to severe systemic lupus erythematosus (SLE) despite standard therapy.

Objectives:

To characterize the PK/PD relationship of anifrolumab and to confirm anifrolumab 300 mg provides adequate PD neutralization in IFNGS test–high patients.

Methods:

This study included IFNGS test–high patients from the phase 3 randomized, placebo-controlled, 52-week TULIP-12 (NCT02446912) and TULIP-23 (NCT02446899) trials of intravenous anifrolumab 150 mg or 300 mg Q4W plus standard therapy. IFNGS test status (high or low) at screening was classified with an analytically validated 4-gene qPCR based test on whole blood.2 PD neutralization was measured with 21-gene type I IFNGS and expressed as a percentage change from baseline.3 For the graphic PK/PD analysis, patients with ≥1 quantifiable serum PK sample and ≥1 PD measurement before discontinuation were categorized depending on Cave (individual predicted average anifrolumab concentration over treatment duration) median and tertiles (T) for anifrolumab 150 mg and 300 mg, respectively. Median PD IFNGS neutralization and medium absolute deviations were compared across Cave subgroups. PK/PD modeling was assessed in patients with ≥1 quantifiable serum PK sample and a baseline and ≥1 postbaseline PD measurement before discontinuation, using a nonlinear mixed-effects model (NONMEM; version 7.3; ICON) to estimate parameters and characterize the PK/PD data. The PD/efficacy analysis included patients with ≥1 postbaseline PD measurement before discontinuation. BILAG-based Combined Lupus Assessment (BICLA) response rates at Week (W)52 were compared across median PD neutralization quartiles (Q) for pooled anifrolumab 300 mg and 150 mg groups.

Results:

The PK/PD graphic analysis included 654 IFNGS test–high patients (placebo [n=293]; anifrolumab 150 mg [n=72] or 300 mg [n=289]). Cave was generally higher with anifrolumab 300 mg (µg/mL, TULIP-1: T1 <32, T2 32–<44.3, T3 ≥44.3; TULIP-2: T1 <32.4, T2 32.4–<47.9, T3 ≥47.9) than with anifrolumab 150 mg (median 11.5 µg/mL); overlap between anifrolumab 300 mg and 150 mg Cave subgroups was small owing to nonlinearity. Anifrolumab 300 mg elicited rapid (by W44) and sustained median PD neutralization >80%, vs a lower and delayed PD neutralization (median >50% at W52) with anifrolumab 150 mg, and minimal PD neutralization with placebo. The median PD neutralization increased with higher Cave subgroups, plateauing at ~90% at W12–W52. All anifrolumab 300 mg Cave tertiles had a median PD neutralization ~80%; however, the variability was greater in the lowest Cave tertiles vs higher Cave tertiles across trials (Figure 1). The PK/PD modeling, which included 646 IFNGS test–high patients (placebo [n=289], anifrolumab 150 mg [n=70] or 300 mg [n=287]), gave an IC80 estimate of 3.88 μg/mL. The median W24 (study midpoint) Ctrough was higher with anifrolumab 300 mg vs 150 mg (15.6 vs 0.2 μg/mL); thus, the W24 Ctrough exceeded the IC80 in a higher proportion of patients treated with anifrolumab 300 mg vs 150 mg (~83% vs ~27%). The PD/efficacy analysis included 341 patients who received anifrolumab. Higher median percentage PD neutralization quartiles (Q1 <51.7%, Q2 51.7%–85.3%, Q3 85.3%–92.6%, Q4 >92.6%) were associated with higher W52 BICLA response rates (Q1 37.6%, Q2 49.4%, Q3 51.8%, Q4 58.1%).

Conclusion:

In TULIP-1 and TULIP-2, anifrolumab 300 mg yielded higher anifrolumab Cave vs 150 mg. High Cave was associated with rapid (W44–W12), substantial, and sustained PD neutralization of the 21-gene IFNGS in IFNGS test–high patients, which in turn was associated with higher efficacy.

References:

[1]Kuruvilla D. Poster 360, AAPS 2020.

[2]Furie RA. Lancet Rheumatol. 2019;1:e208–19.

[3]Morand EF. N Engl J Med. 2020;382:211–21.

[4]Furie R. Arthritis Rheumatol. 2017;69:379–86.

Acknowledgements:

Writing assistance by Matilda Shackley, MPhil, of JK Associates Inc., part of Fishawack Health. This study was sponsored by AstraZeneca.

Disclosure of Interests:

Yen Lin Chia Employee of: AstraZeneca, Raj Tummala Employee of: AstraZeneca, Tu Mai Employee of: Genentech, Tomas Rouse Employee of: AstraZeneca, Wendy White Employee of: AstraZeneca, Eric F. Morand Speakers bureau: AstraZeneca, Consultant of: AstraZeneca, Grant/research support from: AstraZeneca, Richard Furie Consultant of: AstraZeneca, Grant/research support from: AstraZeneca

POS0684 RELATIONSHIP OF ANIFROLUMAB PK WITH EFFICACY AND SAFETY IN PATIENTS WITH SLE

Background:

In patients with systemic lupus erythematosus (SLE), the type I interferon (IFN) receptor inhibitor anifrolumab was well tolerated and was associated with greater percentages of patients with BILAG–based Composite Lupus Assessment (BICLA) responses vs placebo in 2 phase 3 trials: TULIP-11 (secondary endpoint) and TULIP-22 (primary endpoint).

Objectives:

To characterize the relationship of anifrolumab pharmacokinetics (PK) with BICLA response and safety using pooled data from the TULIP trials.

Methods:

This analysis included patients with moderate to severe SLE despite standard therapy who had ≥1 dose of investigational product and ≥1 quantifiable PK observation in the randomized, placebo-controlled, 52-week TULIP-1 (NCT02446912) and TULIP-2 (NCT02446899) trials of intravenous anifrolumab (every 4 weeks).1,2 The distributions of average anifrolumab serum concentrations (Cave) during treatment were similar between TULIP-1 and TULIP-2, allowing for data pooling for all analyses. For the exposure–BICLA analysis, the proportions of patients with BICLA responses at Week (W)52 (and corresponding 95% confidence intervals [CIs]) in each quartile/tertile of Cave were compared for anifrolumab 300 mg and placebo groups in all patients, patients who completed treatment, and IFN gene signature (IFNGS) test–high patients who completed treatment, using average marginal effect logistic regression (stratified by SLE Disease Activity Index 2000 total score at screening, IFNGS status at screening, and Day 1 glucocorticoid dosage [mg/day]). The relationships between exposure and key safety events were similarly assessed. Analyses presented focus on the anifrolumab 300 mg dose.

Results:

Of the patients in TULIP-1/TULIP-2 who received anifrolumab 300 mg (n=356) or placebo (n=366), 574 completed treatment, of whom 470 were IFNGS test–high at screening. In the exposure–BICLA response analyses, differences favoring anifrolumab 300 mg vs placebo were observed across Cave subgroups among all patients, patients who completed treatment, and IFNGS test–high patients who completed treatment (Table 1). Among IFNGS test–high patients who completed treatment, logistic regression identified Cave as a significant covariate for BICLA response. There was no evidence that the incidence of non-opportunistic serious infections, or increased incidence of herpes zoster (HZ) or infusion-related reactions associated with anifrolumab, were exposure-driven (Figure 1); the incidence of malignancy was low in the anifrolumab 300 mg and placebo groups (<1%), with no evidence that malignancy was exposure-driven through W52.

Conclusion:

Consistent benefit in favor of anifrolumab 300 mg vs placebo was observed in W52 BICLA responses across Cave subgroups. Cave was a significant covariate of efficacy in IFNGS test–high patients who completed treatment. There was no evidence of exposure-driven HZ, non-opportunistic serious infections, infusion-related reactions, or malignancy during the TULIP trials.

References:

[1]Furie R. Lancet Rheumatol. 2019;1:e208–19.

[2]Morand E. N Engl J Med. 2020;382:211–21.

Table 1.

Exposure–BICLA Analysis for Pooled TULIP Data

BICLA response, W52PK subgroupaAnifrolumab 300 mg,n/Nb(%)Anifrolumab vs placebo difference, % [95% CI]All patients (n=722)Q140/100 (40)9.6 [–1.0, 20.3]Q244/98 (44)13.4 [2.6, 24.2]Q343/81 (53)22.5 [10.7, 34.3]Q444/77 (58)27.4 [15.4, 39.4]Placebo112/366 (31)–Patients completing treatment (n=574)Q140/75 (54)12.7 [0.1, 25.2]Q244/74 (57)15.5 [2.7, 28.3]Q343/74 (58)17.2 [4.7, 29.8]Q444/75 (60)18.7 [6.2, 31.2]Placebo112/276 (41)–IFNGS test–high patients completing treatment (n=470)T144/81 (54)15.4 [3, 27.8]T246/81 (54)15.4 [2.8, 27.9]T352/81 (66)26.7 [14.7, 38.7]Placebo88/227 (39)–

BICLA, British Isles Lupus Assessment Group–based Composite Lupus Assessment;

CI, confidence interval; IFNGS, interferon gene signature; PK, pharmacokinetic; Q, quartile; T, tertile.

aPK was stratified by quartiles/tertiles based on sample size.

bn, number of BICLA responders; N, number of patients in the subgroup.

Acknowledgements:

Writing assistance by Alexus Rivas, PharmD, and Rosie Butler, PhD, of JK Associates Inc., part of Fishawack Health.

This study was sponsored by AstraZeneca.

Disclosure of Interests:

Yen Lin Chia Employee of: AstraZeneca, Jianchun Zhang Employee of: Fate Therapeutics, AstraZeneca (former), Raj Tummala Employee of: AstraZeneca, Tomas Rouse Employee of: AstraZeneca, Richard Furie Consultant of: AstraZeneca, Grant/research support from: AstraZeneca, Eric F. Morand Speakers bureau: AstraZeneca, Consultant of: AstraZeneca, Grant/research support from: AstraZeneca

Pharmacokinetics, pharmacodynamics, and safety of subcutaneous anifrolumab in patients with systemic lupus erythematosus, active skin disease, and high type I interferon gene signature: a multicentre, randomised, double-blind, placebo-controlled, phase 2 study

BACKGROUND

300 mg of intravenous anifrolumab every 4 weeks added to standard-of-care treatment for patients with systemic lupus erythematosus (SLE) reduced disease activity and glucocorticoid requirement in a previous phase 3 trial. Because patients might find subcutaneous administration more convenient than intravenous delivery, we aimed to evaluate the pharmacokinetics, pharmacodynamics, safety, and efficacy of subcutaneous anifrolumab in patients with SLE, active skin disease, and a high type I interferon gene signature.

METHODS

This multicentre, randomised, double-blind, placebo-controlled, phase 2 study was done at 12 hospitals and outpatient clinics in Hungary, South Korea, Poland, and the USA. Eligible patients were aged 18-70 years, and had SLE with high type I interferon gene signature and an activity score on the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI) of at least 10. Enrolled participants were randomly assigned (3:1:3:1) by use of a voice-web response system to receive either 150 mg of subcutaneous anifrolumab or corresponding placebo, or 300 mg of subcutaneous anifrolumab or corresponding placebo in addition to stable standard-of-care treatment. The study was double-blinded with respect to intervention but not dose, until 12 weeks. Doses of oral glucocorticoids were tapered after week 12. The primary pharmacokinetic endpoint was the serum concentration of anifrolumab based on the maximum concentration after the first dose and the minimum (trough) concentration before subsequent doses and was measured in all patients who received anifrolumab and had at least one quantifiable serum pharmacokinetics observation following the first dose. The primary pharmacodynamic endpoint was neutralisation of the type I interferon pharmacodynamic signature at week 12 and was assessed in all patients with a high type I interferon pharmacodynamics signature at baseline based on a 21-gene test. Safety was evaluated in the full analysis set, which included all patients who received at least one dose of anifrolumab. This trial is completed and is registered at ClinicalTrials.gov, NCT02962960.

FINDINGS

Between March 14, 2017, and Oct 26, 2017, 36 patients were randomly assigned to receive 150 mg of anifrolumab (n=14), 300 mg of anifrolumab (n=13), or placebo (n=9). Two patients in the anifrolumab 150 mg group were excluded from the pharmacodynamic analysis set (n=34). Ten (71%) of 14 patients in the anifrolumab 150 mg group, ten (77%) of 13 patients in the anifrolumab 300 mg group, and nine (100%) of the nine patients in the placebo group completed 52 weeks of treatment. At week 12, pre-dose mean trough serum concentrations of anifrolumab were more than dose proportional between the anifrolumab 150 mg group (19·82 μg/mL [SD 15·01]) and the anifrolumab 300 mg group (60·28 μg/mL [43·66]), and the pharmacokinetics were non-linear. At week 12, the median percentage neutralisation of the type I interferon gene signature was higher with 150 mg (88·0% [median absolute deviation 7·4]) and 300 mg (90·7% [3·3]) of anifrolumab than with placebo (18·5% [8·1]), and more patients in the anifrolumab 150 mg group and the anifrolumab 300 mg group than in the placebo group had neutralisation of 75% or more (eight [67%] of 12 vs ten [77%] of 13 vs one [11%] of nine). At least one adverse event was reported by 23 (85%) of 27 patients in the anifrolumab groups and by seven (78%) of nine patients in the placebo group; most adverse events were of mild-to-moderate severity. Serious adverse events were reported in six (22%) of 27 patients in the anifrolumab groups (four patients in the 150 mg group and two in the 300 mg group). No serious adverse events were reported in the placebo group. Herpes zoster infection was reported by three (11%) of 27 patients in the anifrolumab groups and by one (11%) of nine patients in the placebo group. There were no treatment-related deaths.

INTERPRETATION

Anifrolumab, administered subcutaneously every 2 weeks to patients with SLE and moderate-to-severe skin manifestations, had non-linear pharmacokinetics that were more than dose proportional, and neutralised the type I interferon gene signature in a dose-dependent manner. The safety profile was consistent with previous studies of intravenous anifrolumab, supporting the continued development of anifrolumab as a subcutaneously administered therapy for patients with SLE.

FUNDING

AstraZeneca.

Safety, tolerability and pharmacokinetics of subcutaneous and intravenous anifrolumab in healthy volunteers

Objectives

To compare the pharmacokinetics (PK), safety and tolerability of subcutaneous (SC) and intravenous anifrolumab, an anti–type I interferon receptor monoclonal antibody in development for SLE, in healthy volunteers.

Methods

In this Phase I randomised, placebo-controlled study, 30 adults were assigned to three treatment cohorts (anifrolumab 300 mg SC (n=6), anifrolumab 300 mg intravenous (n=6), anifrolumab 600 mg SC (n=6)) and placebo (n=4/cohort). Serial blood samples were collected up to Day 84 to measure anifrolumab concentrations and antidrug antibodies (ADAs). PK parameters were estimated by noncompartmental analysis.

Results

Maximum serum concentrations in SC cohorts occurred after 4–7 days. Anifrolumab serum concentrations were below the limit of detection in all individuals by Day 84. Exposure to SC anifrolumab increased dose proportionally from 300 mg to 600 mg based on area under the serum concentration-time curve. Anifrolumab 300 mg SC exposure reached 87% of the intravenous exposure. Anifrolumab 300 mg SC and placebo administration elicited minimal injection-site reactions. Transient injection-site induration occurred in five of six individuals after anifrolumab 600 mg SC and two of four individuals after placebo. Transient, mild to moderate injection-site induration and pruritus occurred simultaneously in two of six individuals after anifrolumab 600 mg SC. Adverse events were reported by 50% (n=9) of anifrolumab-treated individuals and 33% (n=4) of placebo-treated individuals. ADAs were detected in only one individual in the anifrolumab 300-mg intravenous group at the Day 84 assessment.

Conclusion

Anifrolumab 300-mg SC exposure was 87% of intravenous administration, with single SC anifrolumab administrations well tolerated in healthy volunteers.

A programmable platform for sub-second multichemical dynamic stimulation and neuronal functional imaging in C. elegans

Caenorhabditis elegans (C. elegans) is a prominent model organism in neuroscience, as its small stereotyped nervous system offers unique advantages for studying neuronal circuits at the cellular level. Characterizing temporal dynamics of neuronal circuits is essential to fully understand neuronal processing. Characterization of the temporal dynamics of chemosensory circuits requires a precise and fast method to deliver multiple stimuli and monitor the animal's neuronal activity. Microfluidic platforms have been developed that offer an improved control of chemical delivery compared to manual methods. However, stimulating an animal with multiple chemicals at high speed is still difficult. In this work, we have developed a platform that can deliver any sequence of multiple chemical reagents, at sub-second resolution and without cross-contamination. We designed a network of chemical selectors wherein the chemical selected for stimulation is determined by the set of pressures applied to the chemical reservoirs. Modulation of inlet pressures has been automated to create robust, programmable sequences of subsecond chemical pulses. We showed that stimulation with sequences of different chemicals at the second to sub-second range can generate different neuronal activity patterns in chemosensory neurons; we observed previously unseen neuronal responses to a controlled chemical stimulation. Because of the speed and versatility of stimulus generated, this platform opens new possibilities to investigate neuronal circuits.

Prospective audit of colonoscopy quality in Kent and Medway, UK

AIM

To compare the quality of colonoscopy in the Kent and Medway Strategic Health Authority with national standards and previous audits.

METHOD

A prospective 12-month audit of colonoscopy quality as assessed by number of procedures performed, total colonoscopy rates, sedation usage, and complications. Data were collected by 7 endoscopy units on 5905 colonoscopies performed by 62 colonoscopists. The endoscopy unit nurses, as opposed to the colonoscopists, verified that colonoscopy was total.

RESULTS

Seven doctors stopped performing colonoscopy during the study period. Thirty-nine of 55 colonoscopists (71 %) achieved total colonoscopy in at least 90 % of cases; 12 (22 %) completed colonoscopy in 80 - 89 % of their cases and 4 (7 %) in 79 % or less of their cases. Seventy-nine percent of colonoscopists used sedation in accordance with British Society of Gastroenterology (BSG) guidelines. Only 22 of 55 (40 %) of colonoscopists performed more than 100 colonoscopies during the 12-month audit period. Reported complications were below expected levels.

CONCLUSION

In our study almost one-third of colonoscopists did not achieve colonoscopy completion rates of at least 90%, and less than half performed more than 100 colonoscopies during the 12 month study. Adherence to quality standards appears to be inadequate.

CD4+CD25+ regulatory cells in acquired MHC tolerance

Tolerance to self-antigens is an ongoing process that begins centrally during T-cell maturation in the thymus and continues throughout the cell's life in the periphery by a network of regulated restraints. Remaining self-reactive T-cells that escape intrathymic deletion may be silenced within the peripheral immune system by specialized regulatory CD4+ cells. By analogy, regulatory CD4+ cells that control immunity to "acquired self" should arise in circumstances where the immune system acquires tolerance to foreign MHC, such as the tolerance that develops following the exposure to foreign MHC antigens during the neonatal period. We have used this classic model of neonatal tolerance to examine the role of regulatory CD4+ cells in acquired tolerance to disparate class I and class II MHC. Adoptive transfer of unfractionated but not CD4+-depleted spleen cells from neonatal tolerant mice into SCID recipients inhibited skin graft rejection by immunocompetent CD8+ T cells. Using 5-bromo-2'-deoxyuridine incorporation, standard cytotoxic T-lymphocyte assays, short-term interferon-gamma ELISPOT, and intracellular FACS analysis to study CD8+ T-cell effector function, we demonstrated that neonatal tolerant mice contain CD4+CD25+ cells that suppress the development of anti-donor CD8+ T-cell responses in vitro. We conclude that regulatory CD4+CD25+ cells initiate and/or maintain tolerance by preventing the development of CD8+ T-cell alloreactivity.

Is the grass greener? Early results of the Nuss procedure

BACKGROUND/PURPOSE

Minimal access surgery (MIS, Nuss Procedure) is gaining acceptance rapidly as the preferred method for pectus excavatum repair. This shift in operative management has followed a single institution's evaluation of the procedure. This report describes an additional experience with the Nuss procedure.

METHODS

Twenty-one patients with pectus excavatum underwent repair by the Nuss Procedure. The patients ranged in age from 5 to 15 years (average, 8.2 years). There were 19 boys and 2 girls.

RESULTS

In 1 patient (age 5 years) the MIS procedure was aborted because of persistence of chest wall asymmetry. The other 20 patients had completion of their procedure without intraoperative complication. The operating times ranged from 45 to 90 minutes; however, there was an additional anesthetic set-up time (average, 45 minutes). All cases utilized a single support bar (11 to 17 inches). Patients underwent extubation in the operating room and were admitted to a ward bed with an epidural catheter in place for pain control and received intravenous analgesia. The hospital stay ranged from 4 to 11 days and averaged 4.9 days. Early postoperative complications included ileus (n = 1), bilateral pleural effusion (n = 2), atelectasis (n = 1), fungal dermatitis (n = 1), pneumothorax (n = 1), and flipped pectus bar (n = 2). Delayed complications included flipped pectus bar (n = 2), marked pectus carinatum requiring bar removal (n = 1), mild carinatum (n = 1), mild bar deviation (n = 1), progressive chest wall asymmetry (n = 3) with 1 requiring bar removal and open pectus repair, pleural effusion (n = 1), and chronic persistent pain requiring bar removal (n = 1). The length of follow-up is 3 to 20 months with an average of 12.3 months.

CONCLUSIONS

The Nuss Procedure is quick, minimally invasive, and a technically easy method to learn; however, our data indicate there is a significant learning curve. Although previous reports suggest that few complications occur, we believe further assessment of patient selection regarding age, presence of connective tissue disorder, and severe chest wall asymmetry are still needed. Long-term follow-up also will be required to assure both health professionals and the public that this is the procedure of choice for patients with pectus excavatum.

Traumatic disruption of the thoracic aorta in children

HYPOTHESIS

This study was undertaken to identify mechanisms of injury, diagnostic modalities, surgical management, and outcome in children with traumatic aortic disruptions.

DESIGN

Retrospective study.

SETTING

University-affiliated private hospital.

PATIENTS

All patients younger than 17 years listed in the trauma registry.

INTERVENTION

Operative repair of thoracic aortic injuries.

MAIN OUTCOME MEASURES

There were 8 boys and 3 girls ranging in age from 12 to 17 years (mean, 14.8 years). Seven children were motor vehicle passengers; 3 were pedestrians struck by vehicles; and 1 was thrown from a bull. Aortic injuries were suspected on the basis of the mechanism of injury and abnormal chest x-ray films (mediastinal widening). Aortic injuries were confirmed in 9 patients by arch aortography and in 2 patients by computed tomography. The injuries involved the isthmus of the aorta in 9 patients (complete transections) and the aortic arch in 2 patients (avulsions of the great vessels). Isthmus injuries were repaired by means of left heart bypass with direct cannulation of the distal thoracic aorta in 8 patients and femoral venous to femoral arterial bypass in 1 patient. Arch injuries were repaired during hypothermic circulatory arrest. The injured aortic segments were replaced with interposition grafts. There were no direct complications of anticoagulation. Ten patients (91%) survived. The only death was caused by a severe closed head injury. There were no instances of paraplegia related to aortic repairs.

CONCLUSION

Good outcomes resulted from early diagnosis based on mechanism of injury, prompt aortography, and computed tomography and operative management that included distal aortic perfusion with left heart bypass.

Evidence for excessive Th2 CD4+ subset activity in vivo

Although distinct Th1 and Th2 CD4+ subsets are apparent in in vitro studies, controversy exists over whether these subsets occur functionally in vivo. We describe a patient whose presenting laboratory features of elevated IgG4 and IgE and eosinophilia suggested high levels of IL-4 and IL-5 and in vivo expansion of the CD4+ Th2 subset. Anti-CD3-activated patient PBL induced heightened levels of IgG4 and IgE from normal B cells, indicating that the patient's abnormal Ig isotypes were T cell driven. Stimulated PBL from the patient secreted more IL-4, compared with control PBL, but similar levels of IFN-gamma. Semiquantitative reverse polymerase chain reaction demonstrated that activated PBL from the patient produced higher IL-4 and IL-5, lower IL-2, and similar IFN-gamma mRNA levels, compared with controls. FACS analysis showed that the patient expressed an expanded population of CD4+Leu-8+CD45RA- cells, the memory-effector population, and RNA in situ hybridization confirmed that the CD4+Leu-8+CD45RA- population of the patient was enriched for IL-4-transcribing cells. Moreover, IL-4-transcribing cells outnumbered IFN-gamma-transcribing cells by 2:1 in the memory-effector CD4 population, confirming that Th2 cells exist in vivo within the expanded CD4+Leu-8+CD45RA- population. Taken together, these results provide evidence that Th2 cells exist in vivo and they suggest that the expanded Th2 population produces excessive cytokines that may contribute to the sinopulmonary pathology of the patient.

Evidence for excessive Th2 CD4+ subset activity in vivo

Although distinct Th1 and Th2 CD4+ subsets are apparent in in vitro studies, controversy exists over whether these subsets occur functionally in vivo. We describe a patient whose presenting laboratory features of elevated IgG4 and IgE and eosinophilia suggested high levels of IL-4 and IL-5 and in vivo expansion of the CD4+ Th2 subset. Anti-CD3-activated patient PBL induced heightened levels of IgG4 and IgE from normal B cells, indicating that the patient's abnormal Ig isotypes were T cell driven. Stimulated PBL from the patient secreted more IL-4, compared with control PBL, but similar levels of IFN-gamma. Semiquantitative reverse polymerase chain reaction demonstrated that activated PBL from the patient produced higher IL-4 and IL-5, lower IL-2, and similar IFN-gamma mRNA levels, compared with controls. FACS analysis showed that the patient expressed an expanded population of CD4+Leu-8+CD45RA- cells, the memory-effector population, and RNA in situ hybridization confirmed that the CD4+Leu-8+CD45RA- population of the patient was enriched for IL-4-transcribing cells. Moreover, IL-4-transcribing cells outnumbered IFN-gamma-transcribing cells by 2:1 in the memory-effector CD4 population, confirming that Th2 cells exist in vivo within the expanded CD4+Leu-8+CD45RA- population. Taken together, these results provide evidence that Th2 cells exist in vivo and they suggest that the expanded Th2 population produces excessive cytokines that may contribute to the sinopulmonary pathology of the patient.

Childhood injury: a current perspective

The majority of childhood injuries requiring admission are due to traffic-related injury, falls, and burns. Many of these injuries are preventable. In the case of the unpreventable, unintentional injury, the natural history of the injury and outcome can be altered by adherence to established safety standards. New standards also need to be set. There is definitely room for improvement in vehicular restraint systems for the smaller and younger passengers. It is known that wearing bicycle helmets, using safety belts, securing firearms in the home, and controlling hot water heater temperature levels will prevent or lessen injury in children. This information is being promulgated to communities by activities such as the National SAFE KIDS Campaign, a program of Children's National Medical Center sponsored by Johnson & Johnson Family of Companies and the National Safety Council. This campaign emphasizes important aspects of childhood injury: scope, causes, and prevention. Questions about the most devastating of childhood injuries, child abuse and assault related to violent crime, are more complex and the answers elusive. The study of patterns of injury in children highlights the need to implement new strategies aimed at prevention. At the same time, valuable information is obtained about specific injuries and responses seen in children that set them apart from adults.

Effects of anti-IgM suppression on polyclonally activated murine B cells: analysis of immunoglobulin mRNA, gene specific nuclear factors and cell cycle distribution

Polyclonal activation of murine B cells with bacterial lipopolysaccharide (LPS) and dextran sulfate (DxS) results in cell proliferation as well as increased immunoglobulin gene transcription and antibody secretion. When added to B cell cultures during mitogen activation, anti-mu antibody suppresses the rate of proliferation and immunoglobulin gene expression. Using this model system we show that co-cultures of B cells with LPS/DxS and anti-mu resulted in a decrease of both mu and kappa chain mRNA. Suppression did not prevent B cell entry into cycle nor a significant alteration in the distribution of cells in phases of cell cycle, although it did prolong the cycle transit time in a dose dependent fashion as determined by bromodeoxyuridine pulse labelling. Analysis of B cell specific nuclear binding factors, which previously have been shown to be important in regulating immunoglobulin gene transcription were examined. Results show that the kappa-specific enhancer binding activity of NF-kappa B was induced in activated as well as suppressed cultures. The lymphoid specific factor NF-A2, which recognizes the octamer sequence motif in the promoters of immunoglobulin genes, was induced by the polyclonal activation but was selectively lost in extracts from suppressed cells. Thus, specific regulation of the nuclear factor which plays a critical role in both heavy and light chain immunoglobulin gene expression may contribute to the transcriptional suppression observed in anti-mu treated B cells.

Isolated injury to the intestine from blunt abdominal injury

Isolated injury to the intestine due to blunt abdominal trauma is an uncommon event. Since the haemodynamic disturbance which accompanies injury of the liver or spleen is absent the initial symptoms and signs may be very slight, or obscured by injuries of the abdominal wall, musculoskeletal or nervous systems. We present four cases which illustrate pitfalls in management. A high index of suspicion is essential if morbidity and mortality are to be reduced to a minimum. Abdominal radiography and peritoneal lavage are useful aids when diagnosis is in doubt.