Real-World Outcomes of Ranibizumab Treatment in French Patients with Visual Impairment due to Macular Edema Secondary to Retinal Vein Occlusion: 24-Month Results from the BOREAL-RVO Study.

INTRODUCTION: Information about real-world ranibizumab use is needed to optimize treatment of macular edema secondary to retinal vein occlusion (RVO). The BOREAL-RVO study assessed treatment use, effectiveness, and safety of 24-month treatment with ranibizumab 0.5 mg in patients with visual impairment due to macular edema secondary to RVO in a real-world setting. METHODS: This was a multicenter, post-authorization, observational study in France, including patients starting ranibizumab for RVO. Primary endpoint was mean change from baseline in best-corrected visual acuity (BCVA) at month 6. Secondary endpoints were mean changes from baseline in BCVA at month 24 and central retinal thickness (CRT) at months 6 and 24, and treatment use in real-world setting. RESULTS: 226 branch RVO (BRVO) and 196 central RVO (CRVO) patients were enrolled; 71.7% and 70.9% completed the 24-month follow-up, respectively. In BRVO, mean (SD) baseline BCVA was 55.2 (18.7) letters, with gains of 14.3 (13.7), 14.1 (16.5), 13.0 (17.5), and 11.4 (20.1) letters at months 3, 6, 12, and 24, respectively. In CRVO, mean (SD) baseline BCVA was 40.4 (25.6) letters, with gains of 16.0 (21.2), 9.5 (25.4), 9.2 (27.7), and 8.3 (23.8) letters at months 3, 6, 12, and 24, respectively. At month 24, 52% of BRVO and 41% of CRVO patients had gains of 15 or more letters. In BRVO, mean (SD) CRT values at baseline and months 3, 6, 12, and 24 were 550 (175), 315 (104), 343 (122), 335 (137), and 340 (105) µm. In CRVO, mean (SD) CRT values at baseline and months 3, 6, 12, and 24 were 643 (217), 327 (152), 400 (203), 379 (175), and 348 (161) µm. On average, BRVO patients had 3.8 injections for 6.9 visits by month 6, and 7.2 injections for 19.7 visits by month 24. CRVO patients had 2.7 injections for 4.2 visits by month 6 and 7.1 injections for 21.1 visits by month 24. Factors predictive of better BCVA gain at month 6 were age under 60 at baseline, lower baseline BCVA and BCVA gain at month 3. There were no new safety findings. CONCLUSION: Major improvements in BCVA and CRT were observed at month 3 after the induction phase and then were sustained up to month 24, with a slight decrease, probably due to under-treatment. This study demonstrated ranibizumab to be a safe and effective treatment for BRVO and CRVO in the real-world setting, although more regular or proactive treatment could further improve outcomes.

Effect of Intralipid® on the Dose of Ropivacaine or Levobupivacaine Tolerated by Volunteers: A Clinical and Pharmacokinetic Study.

BACKGROUND: Rapid intravenous administration of lipid emulsion has become the standard treatment of severe local anesthetic systemic toxicity. This experiment in volunteers aimed at determining the effect of Intralipid® administration on the time to neurologic symptoms. METHODS: Ropivacaine or levobupivacaine was infused intravenously in 16 volunteers (8 mg/min up to 120 mg) with 120 ml Intralipid® 20% (Fresenius, Paris France) or placebo infused at T + 2 min). Each subject received all four treatments in a crossover manner. The infusion was stopped after the intended dose had been administered or on occurrence of incipient neurologic signs of toxicity. The primary outcome was time-to-event. In addition, blood ropivacaine and levobupivacaine concentrations were measured. RESULTS: The dose infused was not different whether volunteers received placebo (81.7 ± 22.3 vs. 80.8 ± 31.7 mg, ropivacaine vs. levobupivacaine) or Intralipid® (75.7 ± 29.1 vs. 69.4 ± 26.2 mg, ropivacaine vs. levobupivacaine), P = 0.755, Intralipid® versus placebo groups. Plasma concentrations were best modeled with an additional volume of distribution associated with Intralipid®. Simulations suggested that decreased peak concentrations would be seen if Intralipid® was given during a period of increasing concentrations after extravascular administration. CONCLUSIONS: At modestly toxic doses of ropivacaine or levobupivacaine, we were unable to find any effect of the infusion of Intralipid® on the time to early signs of neurologic toxicity in volunteers. Peak concentration was decreased by 26 to 30% in the subjects receiving Intralipid®. Simulations showed that Intralipid® might prevent the rapid increase of local anesthetic concentration after extravascular administration.

Age-dependent Mendelian predisposition to herpes simplex virus type 1 encephalitis in childhood.

OBJECTIVE: To test the hypothesis that predisposition to childhood herpes simplex virus (HSV) type 1 encephalitis (HSE) may be determined in part by human genetic factors. STUDY DESIGN: A genetic epidemiologic survey of childhood HSE (onset at age 3 months to 15 years) over a 20-year period (1985-2004) was conducted throughout France (comprising 29 university hospital neuropediatric centers). A total of 85 children fulfilled the diagnostic criteria for inclusion. Family and personal histories were obtained by face-to-face interview for 51 patients. RESULTS: No familial cases of HSE were identified in our survey; however, a high proportion (20%) of the children interviewed had a relevant family history: parental consanguinity (12% of patients), early-onset herpetic keratitis in a first-degree relative (6%), or both (2%). The narrow window of high susceptibility to HSE before age 3 years (62% of patients) further indicates that predisposition to HSE is tightly age-dependent. CONCLUSIONS: This survey suggests that childhood HSE, although sporadic, may result from Mendelian predisposition (from autosomal recessive susceptibility in particular), at least in some children. There likely is incomplete penetrance, however, which may reflect, at least in part, the impact of age at the time of HSV-1 infection.

Paradoxical anti-TNF-associated TB worsening: Frequency and factors associated with IRIS.

OBJECTIVES: Paradoxical tuberculosis (TB) worsening, an example of the immune reconstitution inflammatory syndrome (IRIS), is an increasing phenomenon now described in several settings, including anti-tumor necrosis factor (TNF) discontinuation during biotherapy-induced TB. To better recognize it, we analyzed the frequency and factors associated with anti-TNF-induced TB-IRIS. METHODS: Case-control study on anti-TNF-associated TB patients. IRIS cases, defined with the following consensus criteria, were matched to two controls (anti-TNF-associated TB without IRIS). IRIS frequency was based on the French RATIO registry. Conditional logistic-regression identified IRIS risk factors. RESULTS: Fourteen patients developed anti-TNF-associated TB-IRIS within medians of 45 [IQR 22-131] days after starting anti-TB therapy and 110 [IQR 63-164] days after the last anti-TNF infusion. Each case was matched to two controls by year of TB diagnosis. IRIS-associated factors were (odds ratio [95% CI]): disseminated TB (11.4 [1.4-92.2], P=0.03), history of Mycobacterium tuberculosis exposure (12.7 [1.6-103.0], P=0.02) and steroid use at the time of TB diagnosis (4.6 [1.2-17.2], P=0.02). The RATIO registry IRIS frequency was 7%. CONCLUSION: After stopping biotherapy, paradoxical anti-TNF-associated TB worsening occurred most often in patients with disseminated TB. Although diagnosis remains difficult, physicians must be aware of IRIS because prolonged anti-TB treatment is not needed but, paradoxically, immunosuppressant reintroduction may be.

Intravenous Clopidogrel (MDCO-157) Compared with Oral Clopidogrel: The Randomized Cross-Over AMPHORE Study.

BACKGROUND: The extent of P2Y12 inhibition during coronary intervention is an important determinant of ischemic complications. The currently available oral P2Y12 inhibitors are limited by a relatively slow onset of action and variable on-treatment response. OBJECTIVE: Our objective was to determine the pharmacodynamic (PD) dose-antiplatelet response relationship and the pharmacokinetics of MDCO-157, an intravenous formulation of clopidogrel complexed with sulphobutylether betacyclodextrin, and to identify the dose level of MDCO-157 that matches the PD effect of oral clopidogrel 300 mg. METHODOLOGY: A randomized open-label crossover study was performed in 33 healthy adult volunteers to determine the pharmacokinetic (clopidogrel and clopidogrel H4 thiol active metabolite) and the PD (vasodilator-stimulated phosphoprotein [VASP]) effects of MDCO-157 at doses of 75, 150, and 300 mg and of oral clopidogrel 300 mg. RESULTS: Data are presented as %, mean (standard deviation). The maximum effect of P2Y12 receptor inhibition assessed by flow cytometry using VASP was 70.42 (6.7), 69.45 (7.1), and 65.58 (12.6) for intravenous MDCO-157 at doses of 75, 150, and 300 mg, respectively, compared with 56.6 (17.5) with oral clopidogrel 300 mg administration (p < 0.0001). Intravenous administration of MDCO-157 led to a stepwise increase in plasma exposure of clopidogrel, higher than with administration of an oral dose of 300 mg (p < 0.0001). Plasma exposure of H4-thiol also increased with intravenous dose (3.6 ± 2.6, 6.9 ± 4.6, and 12.4 ± 9.1 h·ng/ml for intravenous 75, 150, and 300 mg, respectively) but was lower than with oral administration of a 300-mg dose (34.0 ± 16.0 h.ng/ml; pairwise p < 0.0001). CONCLUSIONS: MDCO-157, an intravenous formulation of clopidogrel complexed with sulphobutylether betacyclodextrin, did not show significant platelet inhibition when administered at doses up to 300 mg. Higher doses with longer infusion may be needed to reach a sufficient threshold of active metabolite generation. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01860105.

Emergency admissions for major haemorrhage associated with antithrombotics: a cohort study.

INTRODUCTION: to describe antithrombotic-related major haemorrhage, therapeutic management and outcomes in patients admitted to an emergency department of a teaching hospital. MATERIAL AND METHOD: This prospective cohort included patients older than 16years with antithrombotic-related major haemorrhage identified by monthly diagnostic codes computerised requests. Major haemorrhage was defined by at least one the following criteria: unstable hemodynamic, haemorrhagic shock, uncontrollable bleeding, need for transfusion or haemostatic procedure, or a life threatening location. RESULTS: between January 1, 2011 and December 31, 2012, 913 patients met the inclusion criteria (1.2 patients per day), median age 82. Oral anticoagulants alone or in combination were used by 429 patients, antiplatelet agents (alone or dual therapy) by 420 patients, and parenteral anticoagulants by 64 patients. Major haemorrhages were: gastrointestinal bleeding (37.5%), intracranial haemorrhage (34.4%), muscular hematoma (9.4%), external haemorrhage (16.9%) and internal haemorrhage (1.9%). At 1month, 179 patients (19.8%) died, mostly patients with intracranial haemorrhage (64.2%). Prognostic factors for death were age and Glasgow coma scale at admission for intracranial haemorrhage, age and mean arterial pressure at admission for other major haemorrhages. Oral anticoagulant therapy was a predictor for death in intracranial haemorrhages. Reversal therapy was initiated in only 50.5% of patients with vitamin K antagonists, without effect on the mortality rate. CONCLUSION: This study shows the magnitude and the severity of antithrombotic-related major haemorrhage. The high mortality rate supports careful awareness in individual risk benefit assessment, especially for elderly.

The cerebral cost of breathing: an FMRI case-study in congenital central hypoventilation syndrome.

Certain motor activities--like walking or breathing--present the interesting property of proceeding either automatically or under voluntary control. In the case of breathing, brainstem structures located in the medulla are in charge of the automatic mode, whereas cortico-subcortical brain networks--including various frontal lobe areas--subtend the voluntary mode. We speculated that the involvement of cortical activity during voluntary breathing could impact both on the "resting state" pattern of cortical-subcortical connectivity, and on the recruitment of executive functions mediated by the frontal lobe. In order to test this prediction we explored a patient suffering from central congenital hypoventilation syndrome (CCHS), a very rare developmental condition secondary to brainstem dysfunction. Typically, CCHS patients demonstrate efficient cortically-controlled breathing while awake, but require mechanically-assisted ventilation during sleep to overcome the inability of brainstem structures to mediate automatic breathing. We used simultaneous EEG-fMRI recordings to compare patterns of brain activity between these two types of ventilation during wakefulness. As compared with spontaneous breathing (SB), mechanical ventilation (MV) restored the default mode network (DMN) associated with self-consciousness, mind-wandering, creativity and introspection in healthy subjects. SB on the other hand resulted in a specific increase of functional connectivity between brainstem and frontal lobe. Behaviorally, the patient was more efficient in cognitive tasks requiring executive control during MV than during SB, in agreement with her subjective reports in everyday life. Taken together our results provide insight into the cognitive and neural costs of spontaneous breathing in one CCHS patient, and suggest that MV during waking periods may free up frontal lobe resources, and make them available for cognitive recruitment. More generally, this study reveals how the active maintenance of cortical control over a continuous motor activity impacts on brain functioning and cognition.

Low-dose interleukin 2 in patients with type 1 diabetes: a phase 1/2 randomised, double-blind, placebo-controlled trial.

BACKGROUND: An improper balance of regulatory/effector T (Treg/Teff) cells is central to the development of autoimmune diseases, including type 1 diabetes. We previously showed that low-dose interleukin 2 (IL2) induced Treg cell expansion and activation and clinical improvement in patients with hepatitis-C-virus-induced vasculitis. We aimed to establish which low doses of IL2 would be safe and induce Treg cells in patients with type 1 diabetes, considering that: (1) type 1 diabetes might be linked to alteration of the IL2/IL2R activation pathway; (2) activation of pathogenic Teff cells by IL2 could exacerbate disease; and (3) the safety of low-dose IL2 is not known in type 1 diabetes. METHODS: This was a single-centre phase 1/2 study. 24 adult patients (18-55 years) with established insulin-dependent type 1 diabetes and at least one diabetes-related autoantibody were enrolled and randomly assigned (in a 1:1:1:1 ratio, by computer-generated randomisation list, with block size four) to placebo or IL2 at 0.33 MIU/day, 1 MIU/day, or 3 MIU/day for a 5-day course and were followed up for 60 days. All investigators and participants were masked to assignment. The primary outcome was change in Treg cells, measured by flow cytometry, and expressed as a percentage of CD4+ T cells, from day 1 to day 60. This trial is registered with ClinicalTrials.gov, number NCT01353833. FINDINGS: Six patients were assigned to each group between June 1, 2011, and Feb 3, 2012. IL2 was well tolerated at all doses, with no serious adverse events. However, there was a dose-response association for non-serious adverse events during the treatment phase (days 1-6); one patient in the placebo group, three patients in the 0.33 MIU group, five patients in the 1 MIU group, and six patients in the 3 MIU group had non-serious adverse events. The most common adverse events in the treatment phase were injection-site reaction (no patients with placebo vs three patients with 0.33 MIU and 1 MIU vs two patients with 3 MIU) and influenza-like syndrome (no patients with placebo vs one patient with 0.33 MIU and 1 MIU vs four patients with 3 MIU). After the treatment phase, adverse events did not differ between groups. IL2 did not induce deleterious changes in glucose-metabolism variables. IL2 induced a dose-dependent increase in the proportion of Treg cells, significant at all doses compared with placebo (placebo mean increase 0.5% [SD 0.4]; 0.33 MIU 2.8% [1.2], p=0.0039; 1 MIU 3.9% [1.8], p=0.0039; 3 MIU 4.8% [1.9] p=0.0039). INTERPRETATION: We have defined a well-tolerated and immunologically effective dose range of IL2 for application to type 1 diabetes therapy and prevention, which could be relevant to other disorders in which a Treg cell increase would be desirable.

Incidence and risk factors of Legionella pneumophila pneumonia during anti-tumor necrosis factor therapy: a prospective French study.

OBJECTIVE: Our objective was to describe the incidence and risk factors of legionellosis associated with tumor necrosis factor (TNF)-α antagonist use. METHODS: From February 1, 2004, to January 31, 2007, we prospectively collected all cases of legionellosis among French patients receiving TNF-α antagonists in the Research Axed on Tolerance of Biotherapies (RATIO) national registry. We conducted an incidence study with the French population as a reference and a case-control analysis with four control subjects receiving TNF-α antagonists per case of legionellosis. RESULTS: Twenty-seven cases of legionellosis were reported. The overall annual incidence rate of legionellosis for patients receiving TNF-α antagonists, adjusted for age and sex, was 46.7 (95% CI, 0.0-125.7) per 100,000 patient-years. The overall standardized incidence ratio (SIR) was 13.1 (95% CI, 9.0-19.1; P < .0001) and was higher for patients receiving infliximab (SIR, 15.3 [95% CI, 8.5-27.6; P < .0001]) or adalimumab (SIR, 37.7 [95% CI, 21.9-64.9; P < .0001]) than etanercept (SIR, 3.0 [95% CI, 1.00-9.2; P = .06]). In the case-control analysis, exposure to adalimumab (OR, 8.7 [95% CI, 2.1-35.1]) or infliximab (OR, 9.2 [95% CI, 1.9-45.4]) vs etanercept was an independent risk factor for legionellosis. CONCLUSIONS: The incidence rate of legionellosis for patients receiving TNF-α antagonists is high, and the risk is higher for patients receiving anti-TNF-α monoclonal antibodies than soluble TNF-receptor therapy. In case of pneumonia occurring during TNF-α antagonist therapy, specific urine antigen detection should be performed and antibiotic therapy should cover legionellosis. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00224562; URL: www.clinicaltrials.gov.

ZNF703 gene amplification at 8p12 specifies luminal B breast cancer.

Luminal B breast cancers represent a fraction of oestrogen receptor (ER)-positive tumours associated with poor recurrence-free and disease-specific survival in all adjuvant systemic treatment categories including hormone therapy alone. Identification of specific signalling pathways driving luminal B biology is paramount to improve treatment. We have studied 100 luminal breast tumours by combined analysis of genome copy number aberrations and gene expression. We show that amplification of the ZNF703 gene, located in chromosomal region 8p12, preferentially occurs in luminal B tumours. We explored the functional role of ZNF703 in luminal B tumours by overexpressing ZNF703 in the MCF7 luminal cell line. Using mass spectrometry, we identified ZNF703 as a co-factor of a nuclear complex comprising DCAF7, PHB2 and NCOR2. ZNF703 expression results in the activation of stem cell-related gene expression leading to an increase in cancer stem cells. Moreover, we show that ZNF703 is implicated in the regulation of ER and E2F1 transcription factor. These findings point out the prominent role of ZNF703 in transcription modulation, stem cell regulation and luminal B oncogenesis.

Availability of the epinephrine autoinjector at school in children with peanut allergy.

BACKGROUND: Peanut allergy accounts for most severe food-related allergic reactions, and accidental exposures are frequent. Delayed administration of epinephrine and the allergic individual's failure to personally carry epinephrine contribute to fatal outcomes. OBJECTIVES: To describe epinephrine autoinjector availability at school and to determine factors that might affect autoinjector availability in children allergic to peanut. METHODS: Two hundred seventy-one children with peanut allergy living in Quebec were queried about their autoinjector. Logistic regression models were used to select factors associated with device availability. RESULTS: Four of 271 children diagnosed as having peanut allergy were not prescribed autoinjectors. Forty-eight percent of the children did not carry the autoinjector with them at school. In 78.0% of those, the autoinjector was located in the nurse's or another school office, which was staffed by a full-time nurse only in 18.5%. Of all the respondents, those administered epinephrine for a previous reaction (odds ratio [OR], 2.7; 95% confidence interval [CI], 1.3-5.7), older children (OR, 1.1; 95% CI, 1.0-1.2), and those living only with their mother (OR, 3.4; 95% CI, 1.0-11.0) were more likely to carry the autoinjector with them at school. Of children 7 years or older, those who experienced a severe reaction were more likely to carry their autoinjector (OR, 3.3; 95% CI, 1.4-8.1). CONCLUSIONS: Almost 50% of children allergic to peanut might experience a delay in anaphylaxis treatment due to limited access to their device. More education is required regarding the importance of a readily available autoinjector.

Accidental ingestions in children with peanut allergy.

BACKGROUND: Accidental exposure to peanut has been reported to occur frequently. Total avoidance of peanut is difficult because of its widespread use, manufacturing and labeling errors, utensil contamination, and label misinterpretation. OBJECTIVE: Given the apparent increased awareness of peanut allergy by both consumers and food manufacturers, we aimed to determine the current frequency of accidental exposures occurring in peanut allergic children in Quebec and to identify factors associated with exposure. METHODS: The parents of children with peanut allergy diagnosed at the Montreal Children's Hospital completed questionnaires about accidental exposure to peanut occurring over the period of the preceding year. Logistic regression was used to identify associated factors. RESULTS: Of 252 children, 62% were boys, with a mean age of 8.1 years (SD, 2.9). The mean age at diagnosis was 2.0 years (SD, 2.1). Thirty-five accidental exposures occurred in 29 children over a period of 244 patient-years, yielding an annual incidence rate of 14.3% (95% CI, 10.0% to 19.9%). Fifteen reactions were mild, 16 moderate, and 4 severe. Of 20 reactions that were moderate to severe, only 4 received epinephrine. Eighty percent of children attended schools prohibiting peanut, and only 1 accidental exposure occurred at school. No associated factors were identified. CONCLUSION: Accidental exposure to peanut occurs at a lower frequency than previously reported, but most reactions are managed inappropriately. CLINICAL IMPLICATIONS: Enhanced awareness, access to safer environments, and good food manufacturing practices may have contributed to a lower incidence of inadvertent peanut exposure, but a further reduction and better education on allergy management are desirable.

Herpes simplex virus encephalitis in human UNC-93B deficiency.

Herpes simplex virus-1 (HSV-1) encephalitis (HSE) is the most common form of sporadic viral encephalitis in western countries. Its pathogenesis remains unclear, as it affects otherwise healthy patients and only a small minority of HSV-1-infected individuals. Here, we elucidate a genetic etiology for HSE in two children with autosomal recessive deficiency in the intracellular protein UNC-93B, resulting in impaired cellular interferon-alpha/beta and -lambda antiviral responses. HSE can result from a single-gene immunodeficiency that does not compromise immunity to most pathogens, unlike most known primary immunodeficiencies. Other severe infectious diseases may also reflect monogenic disorders of immunity.

Embryonic deregulation of muscle stress signaling pathways leads to altered postnatal stem cell behavior and a failure in postnatal muscle growth.

PW1 is a mediator of p53 and TNFalpha signaling pathways previously identified in a screen to isolate muscle stem cell regulators. We generated transgenic mice carrying a C-terminal deleted form of PW1 (DeltaPW1) which blocks p53-mediated cell death and TNFalpha-mediated NFkappaB activation fused to the myogenin promoter. Embryonic/fetal muscle development appears normal during transgene expression, however, postnatal transgenic pups display severe phenotypes including runtism, reduced muscle mass and fiber diameters resembling atrophy. Atrogin-1, a marker of skeletal muscle atrophy, is expressed postnatally in transgenic mice. Electron microscopic analyses of transgenic muscle reveal a marked decrease in quiescent muscle satellite cells suggesting a deregulation of postnatal stem cells. Furthermore, transgenic primary myoblasts show a resistance to the effects of TNFalpha upon differentiation. Taken together, our data support a role for PW1 and related stress pathways in mediating skeletal muscle stem cell behavior which in turn is critical for postnatal muscle growth and homeostasis. In addition, these data reveal that postnatal stem cell behavior is likely specified during early muscle development.

Regeneration of natural antibody repertoire after massive ablation of lymphoid system: robust selection mechanisms preserve antigen binding specificities.

Natural Abs (NAbs) are Igs present in the serum and body fluids of healthy vertebrate animals, without any previous intentional immunization. NAbs often exhibit autoreactivity but also play an essential role in immunity, being a first line of defense against infectious microorganisms. We have previously analyzed the natural serum IgM Ab repertoire of normal mice, characterizing their reactivity with hundreds/thousands of self Ags; a significant similarity among different individuals was observed, and it was found that many reactivities of NAbs stably kept during adulthood were established early in life, implicating that period as a critical time window in the physiology of NAb repertoire selection. In the work reported here, experiments were conducted to address the role of normal lymphocyte ontogeny to the formation and stability of adult NAb repertoire. The massive destruction of the lymphoid system was promoted in adult mice with gamma-irradiation, and regeneration of hemopoietic tissues was granted by bone marrow or fetal liver inoculum. NAb repertoire regeneration was followed for 60 days after gamma-irradiation in bone marrow or fetal liver chimeric animals. The analysis of serum IgM reactivity with hundreds/thousands of self Ags showed that the NAb repertoire regenerated most of its original format after massive destruction of lymphoid compartments, characterizing autoreactive repertoire selection as a robust biological process. The data also show that regeneration of the NAb repertoire occurred similarly in fetal liver and bone marrow chimeras, although the latter animals poorly reconstituted their CD5(+) B1 cell compartment, suggesting that B1 cells are not essential for natural Ab regeneration.