Subtyping of Eosinophilic Esophagitis Based on Disease Presentation in a pediatric Cohort.

OBJECTIVE: Eosinophilic esophagitis (EoE) is an immune-mediated inflammatory disease characterized by eosinophilic infiltration of esophageal tissue. Subtyping of EoE patients could be useful in predicting therapeutic response. We propose clinical subtypes, apply them to our pediatric EoE population retrospectively, and assess therapy choices and remission at one year. METHODS: A retrospective chart review of pediatric patients diagnosed with EoE was conducted. Patients were grouped into proposed subtypes (severe, allergic, fibrostenotic, inflammatory, unclassified) based on presenting characteristics. The primary outcome was histologic remission, which was defined <15 eosinophils/high-powered-field (hpf) at the closest visit 1 year postdiagnosis. RESULTS: Subtyping was possible in 242 of 256 patients and follow-up histological data were available in 75 subjects. The majority had an overlap in phenotype with 17% severe, 77% allergic, 15% fibrostenotic, 60% inflammatory, and 5% unclassified, whereas 45% of the cohort were assigned to a unique subtype. At 1 year, 43/75 (57%) of patients achieved histologic remission, with an overall average decrease of 33 (IQR -47, -12) eosinophils/hpf across the entire cohort. There was no difference in remission rates among subtypes. First-line therapy review revealed higher rates of proton pump inhibitor (PPI) ± topical steroids utilization in severe patients, while topical steroids were prescribed preferentially over dietary therapy in the fibrostenotic subtype. CONCLUSION: There were no observed differences in remission rates at 1 year among clinically defined subtypes of EoE, although this could be attributed to overlapping subtypes. Most patients responded well to medical therapy. Larger scale prospective studies designed to subtype patients and protocolize treatment may help personalize the approach to EoE management.

Genetic and mechanistic diversity in pediatric hemophagocytic lymphohistiocytosis.

The HLH-2004 criteria are used to diagnose hemophagocytic lymphohistiocytosis (HLH), yet concern exists for their misapplication, resulting in suboptimal treatment of some patients. We sought to define the genomic spectrum and associated outcomes of a diverse cohort of children who met the HLH-2004 criteria. Genetic testing was performed clinically or through research-based whole-exome sequencing. Clinical metrics were analyzed with respect to genomic results. Of 122 subjects enrolled over the course of 17 years, 101 subjects received genetic testing. Biallelic familial HLH (fHLH) gene defects were identified in only 19 (19%) and correlated with presentation at younger than 1 year of age (P < .0001). Digenic fHLH variants were observed but lacked statistical support for disease association. In 28 (58%) of 48 subjects, research whole-exome sequencing analyses successfully identified likely molecular explanations, including underlying primary immunodeficiency diseases, dysregulated immune activation and proliferation disorders, and potentially novel genetic conditions. Two-thirds of patients identified by the HLH-2004 criteria had underlying etiologies for HLH, including genetic defects, autoimmunity, and malignancy. Overall survival was 45%, and increased mortality correlated with HLH triggered by infection or malignancy (P < .05). Differences in survival did not correlate with genetic profile or extent of therapy. HLH should be conceptualized as a phenotype of critical illness characterized by toxic activation of immune cells from different underlying mechanisms. In most patients with HLH, targeted sequencing of fHLH genes remains insufficient for identifying pathogenic mechanisms. Whole-exome sequencing, however, may identify specific therapeutic opportunities and affect hematopoietic stem cell transplantation options for these patients.

Biologics in pediatric lung disease.

PURPOSE OF REVIEW: Although biologic therapies can provide outstanding efficacy in the management of lung disease, especially asthma, most of these agents have been approved only for adults. Recent findings provide new strategies for using these agents in children. RECENT FINDINGS: Extensive evidence has consistently demonstrated the efficacy and safety of biologic therapy for asthma. In addition, some studies have documented potentially important secondary effects, such as improving response to respiratory virus infection in asthmatic patients. Additional strategies for improving asthma control using biologic therapy, such as seasonal administration, have been suggested, and may limit cost while still providing a high degree of efficacy. SUMMARY: Many of the current biologics are able to readily establish control even in asthmatic patients for whom inhaled steroid and long-acting ß agonist have failed. However, biologics currently have limited regulatory approval and availability in the pediatric age range, despite this age being disproportionately affected by asthma. In addition, successful biologics for asthma to date have largely been limited to the Th2-high endotype of asthma, and there is great need for similar medications to target the Th2-low endotype. Other pediatric lung disease might well benefit from the specificity allowed by biologic therapy.

International consensus guidelines for the diagnosis and management of food protein-induced enterocolitis syndrome: Executive summary-Workgroup Report of the Adverse Reactions to Foods Committee, American Academy of Allergy, Asthma & Immunology.

Food protein-induced enterocolitis (FPIES) is a non-IgE cell- mediated food allergy that can be severe and lead to shock. Despite the potential seriousness of reactions, awareness of FPIES is low; high-quality studies providing insight into the pathophysiology, diagnosis, and management are lacking; and clinical outcomes are poorly established. This consensus document is the result of work done by an international workgroup convened through the Adverse Reactions to Foods Committee of the American Academy of Allergy, Asthma & Immunology and the International FPIES Association advocacy group. These are the first international evidence-based guidelines to improve the diagnosis and management of patients with FPIES. Research on prevalence, pathophysiology, diagnostic markers, and future treatments is necessary to improve the care of patients with FPIES. These guidelines will be updated periodically as more evidence becomes available.

Vehicular exhaust particles promote allergic airway inflammation through an aryl hydrocarbon receptor-notch signaling cascade.

BACKGROUND: Traffic-related particulate matter (PM) has been linked to a heightened incidence of asthma and allergic diseases. However, the molecular mechanisms by which PM exposure promotes allergic diseases remain elusive. OBJECTIVE: We sought to determine the expression, function, and regulation of pathways involved in promotion of allergic airway inflammation by PM. METHODS: We used gene expression transcriptional profiling, in vitro culture assays, and in vivo murine models of allergic airway inflammation. RESULTS: We identified components of the Notch pathway, most notably Jagged 1 (Jag1), as targets of PM induction in human monocytes and murine dendritic cells. PM, especially ultrafine particles, upregulated TH cytokine levels, IgE production, and allergic airway inflammation in mice in a Jag1- and Notch-dependent manner, especially in the context of the proasthmatic IL-4 receptor allele Il4raR576. PM-induced Jag1 expression was mediated by the aryl hydrocarbon receptor (AhR), which bound to and activated AhR response elements in the Jag1 promoter. Pharmacologic antagonism of AhR or its lineage-specific deletion in CD11c(+) cells abrogated the augmentation of airway inflammation by PM. CONCLUSION: PM activates an AhR-Jag1-Notch cascade to promote allergic airway inflammation in concert with proasthmatic alleles.

Primary Immune Deficiency Treatment Consortium (PIDTC) report.

The Primary Immune Deficiency Treatment Consortium (PIDTC) is a network of 33 centers in North America that study the treatment of rare and severe primary immunodeficiency diseases. Current protocols address the natural history of patients treated for severe combined immunodeficiency (SCID), Wiskott-Aldrich syndrome, and chronic granulomatous disease through retrospective, prospective, and cross-sectional studies. The PIDTC additionally seeks to encourage training of junior investigators, establish partnerships with European and other International colleagues, work with patient advocacy groups to promote community awareness, and conduct pilot demonstration projects. Future goals include the conduct of prospective treatment studies to determine optimal therapies for primary immunodeficiency diseases. To date, the PIDTC has funded 2 pilot projects: newborn screening for SCID in Navajo Native Americans and B-cell reconstitution in patients with SCID after hematopoietic stem cell transplantation. Ten junior investigators have received grant awards. The PIDTC Annual Scientific Workshop has brought together consortium members, outside speakers, patient advocacy groups, and young investigators and trainees to report progress of the protocols and discuss common interests and goals, including new scientific developments and future directions of clinical research. Here we report the progress of the PIDTC to date, highlights of the first 2 PIDTC workshops, and consideration of future consortium objectives.

Newborn screening for severe combined immunodeficiency and T-cell lymphopenia in California: results of the first 2 years.

BACKGROUND: Assay of T-cell receptor excision circles (TRECs) in dried blood spots obtained at birth permits population-based newborn screening (NBS) for severe combined immunodeficiency (SCID). OBJECTIVE: We sought to report the first 2 years of TREC NBS in California. METHODS: Since August 2010, California has conducted SCID NBS. A high-throughput TREC quantitative PCR assay with DNA isolated from routine dried blood spots was developed. Samples with initial low TREC numbers had repeat DNA isolation with quantitative PCR for TRECs and a genomic control, and immunophenotyping was performed within the screening program for infants with incomplete or abnormal results. Outcomes were tracked. RESULTS: Of 993,724 infants screened, 50 (1/19,900 [0.005%]) had significant T-cell lymphopenia. Fifteen (1/66,250) required hematopoietic cell or thymus transplantation or gene therapy; these infants had typical SCID (n = 11), leaky SCID or Omenn syndrome (n = 3), or complete DiGeorge syndrome (n = 1). Survival to date in this group is 93%. Other T-cell lymphopenic infants had variant SCID or combined immunodeficiency (n = 6), genetic syndromes associated with T-cell impairment (n = 12), secondary T-cell lymphopenia (n = 9), or preterm birth (n = 8). All T-cell lymphopenic infants avoided live vaccines and received appropriate interventions to prevent infections. TREC test specificity was excellent: only 0.08% of infants required a second test, and 0.016% required lymphocyte phenotyping by using flow cytometry. CONCLUSIONS: TREC NBS in California has achieved early diagnosis of SCID and other conditions with T-cell lymphopenia, facilitating management and optimizing outcomes. Furthermore, NBS has revealed the incidence, causes, and follow-up of T-cell lymphopenia in a large diverse population.

Newborn screening for severe combined immunodeficiency in 11 screening programs in the United States.

IMPORTANCE: Newborn screening for severe combined immunodeficiency (SCID) using assays to detect T-cell receptor excision circles (TRECs) began in Wisconsin in 2008, and SCID was added to the national recommended uniform panel for newborn screened disorders in 2010. Currently 23 states, the District of Columbia, and the Navajo Nation conduct population-wide newborn screening for SCID. The incidence of SCID is estimated at 1 in 100,000 births. OBJECTIVES: To present data from a spectrum of SCID newborn screening programs, establish population-based incidence for SCID and other conditions with T-cell lymphopenia, and document early institution of effective treatments. DESIGN: Epidemiological and retrospective observational study. SETTING: Representatives in states conducting SCID newborn screening were invited to submit their SCID screening algorithms, test performance data, and deidentified clinical and laboratory information regarding infants screened and cases with nonnormal results. Infants born from the start of each participating program from January 2008 through the most recent evaluable date prior to July 2013 were included. Representatives from 10 states plus the Navajo Area Indian Health Service contributed data from 3,030,083 newborns screened with a TREC test. MAIN OUTCOMES AND MEASURES: Infants with SCID and other diagnoses of T-cell lymphopenia were classified. Incidence and, where possible, etiologies were determined. Interventions and survival were tracked. RESULTS: Screening detected 52 cases of typical SCID, leaky SCID, and Omenn syndrome, affecting 1 in 58,000 infants (95% CI, 1/46,000-1/80,000). Survival of SCID-affected infants through their diagnosis and immune reconstitution was 87% (45/52), 92% (45/49) for infants who received transplantation, enzyme replacement, and/or gene therapy. Additional interventions for SCID and non-SCID T-cell lymphopenia included immunoglobulin infusions, preventive antibiotics, and avoidance of live vaccines. Variations in definitions and follow-up practices influenced the rates of detection of non-SCID T-cell lymphopenia. CONCLUSIONS AND RELEVANCE: Newborn screening in 11 programs in the United States identified SCID in 1 in 58,000 infants, with high survival. The usefulness of detection of non-SCID T-cell lymphopenias by the same screening remains to be determined.

Use and interpretation of diagnostic vaccination in primary immunodeficiency: a working group report of the Basic and Clinical Immunology Interest Section of the American Academy of Allergy, Asthma & Immunology.

A major diagnostic intervention in the consideration of many patients suspected to have primary immunodeficiency diseases (PIDDs) is the application and interpretation of vaccination. Specifically, the antibody response to antigenic challenge with vaccines can provide substantive insight into the status of human immune function. There are numerous vaccines that are commonly used in healthy individuals, as well as others that are available for specialized applications. Both can potentially be used to facilitate consideration of PIDD. However, the application of vaccines and interpretation of antibody responses in this context are complex. These rely on consideration of numerous existing specific studies, interpolation of data from healthy populations, current diagnostic guidelines, and expert subspecialist practice. This document represents an attempt of a working group of the American Academy of Allergy, Asthma & Immunology to provide further guidance and synthesis in this use of vaccination for diagnostic purposes in consideration of PIDD, as well as to identify key areas for further research.

Pediatric eosinophilic esophagitis outcomes vary with co-morbid eczema and pollen food syndrome.

Background: Eosinophilic esophagitis (EoE) is a chronic immune-mediated inflammatory disease characterized by eosinophil inflammation of the esophagus. It has been described as a component of the Allergic March and is often seen with other atopic diseases. Some atopic diseases, including asthma, are known to be heterogenous with endotypes that guide treatment. Similarly, we propose that EoE is a heterogenous disease with varying phenotypes and endotypes that might impact response to therapy. Methods: A single-center retrospective review of pediatric patients ≤18 years of age diagnosed with EoE was conducted. All gastrointestinal clinic visits and esophagogastroduodenoscopies (EGD) from disease presentation through the first three years after diagnosis were reviewed. Histologic remission rate and therapies utilized [proton pump inhibitor (PPI), topical steroid, dietary elimination] were assessed. Results: One hundred and thirty-seven patients were included, 80% of whom had at least one concurrent atopic condition at diagnosis, with food allergies being the most common (57%) followed by eczema (34%), and asthma (29%). The remission rate of the overall cohort was 65%, and by concurrent allergy, comorbid pollen food syndrome and eczema had the highest remission rates at 100% and 81%, respectively followed by asthma (62%), food allergies (62%), seasonal allergic rhinitis (60%), and history of anaphylaxis (56%). Kaplan-Meier curves for each atopic condition show that patients with eczema and pollen food syndrome achieve histologic remission faster than those without. All treatment modalities were more successful in patients with eczema than those without, and PPI was most effective treatment at inducing remission. Conclusions: In a real-world pediatric cohort, 80% of patients with EoE had an underlying atopic condition. Patients with eczema and pollen food syndrome had a swifter response and were more likely to achieve histologic remission than patients with other atopic conditions. This study suggests that EoE, like other allergic diseases, may have heterogenous phenotypes that could affect response to treatment. There is currently a knowledge gap in classifying EoE based on endotypes and phenotypes at diagnosis and correlating responses to various treatment modalities.

How the practice of allergy shows the promise and challenge of personalized medicine.

Personalized medicine seeks to stratify therapies according to individual characteristics, and by so doing improve effectiveness and reduce complications. However, there are not many models of care that is highly stratified within a single diagnosis in this manner. One potential model is the practice of allergy, in which care is tailored to specific allergens for individual patients within the broader context of care for rhinitis or asthma. Allergists have already confronted many of the same regulatory issues anticipated for personalized medicine. The history of allergy practice also anticipates some of the patient safety concerns that may arise from tracking and using highly personalized medical information. Finally, the therapy of allergy and asthma has been at the forefront of attempts to incorporate pharmacogenomics information into patient care. Individualized therapy has always been central to the practice of allergy, and so provides a useful proving ground for personalized medicine as a concept of care.

Infant Allergy Testing and Food Allergy Diagnoses Before and After Guidelines for Early Peanut Introduction.

BACKGROUND: A landmark 2015 trial on early exposure to peanuts led to expert recommendations for screening and early peanut introduction in high-risk (severe eczema and/or egg allergy) infants, but the impact of this paradigm shift on allergy testing and diagnosis is unknown. OBJECTIVE: We assessed the effects of the Learning Early About Peanut Allergy (LEAP) trial and guideline publications on allergy testing and food allergy diagnoses in infants. METHODS: In this retrospective cohort study, deidentified administrative health claims from a commercial and Medicare advantage claims database were used. Infants with at least 1 year of continuous coverage were selected using newborn codes for birth hospitalizations from January 2010 to June 2018. Interrupted time series models were used to compare the prevalence of allergy testing before and after LEAP publication in February 2015 and formal guideline publication in January 2017. RESULTS: For 487,533 included infants, allergy testing increased after LEAP (risk ratio [RR]: 1.11 [95% confidence interval (CI), 1.07-1.15]) and guidelines (1.21 [1.18-1.23]). This increase of testing was also seen in infants not considered high risk, both after LEAP (1.12 [1.08-1.17]) and guidelines (1.20 [1.16, 1.23]). For first-time allergy tests, post-guideline median number of allergens tested was 9 for serum tests and 10 for skin tests. Post-guidelines, there was a significant increase in diagnosis of peanut (RR: 1.08 [1.00, 1.16]), egg (1.12 [1.05, 1.20]), and other food allergies (excluding milk) (1.22 [1.14, 1.31]). CONCLUSION: Allergy testing has increased, including in non-high-risk infants. Multiallergen testing may be contributing to an increase in the diagnosis of other food allergies.

Defects along the T(H)17 differentiation pathway underlie genetically distinct forms of the hyper IgE syndrome.

BACKGROUND: The hyper IgE syndrome (HIES) is characterized by abscesses, eczema, recurrent infections, skeletal and connective tissue abnormalities, elevated serum IgE, and diminished inflammatory responses. It exists as autosomal-dominant and autosomal-recessive forms that manifest common and distinguishing clinical features. A majority of those with autosomal-dominant HIES have heterozygous mutations in signal transducer and activator of transcription (STAT)-3 and impaired T(H)17 differentiation. OBJECTIVE: To elucidate mechanisms underlying different forms of HIES. METHODS: A cohort of 25 Turkish children diagnosed with HIES were examined for STAT3 mutations by DNA sequencing. Activation of STAT3 by IL-6 and IL-21 and STAT1 by IFN-alpha was assessed by intracellular staining with anti-phospho (p)STAT3 and -pSTAT1 antibodies. T(H)17 and T(H)1 cell differentiation was assessed by measuring the production of IL-17 and IFN-gamma, respectively. RESULTS: Six subjects had STAT3 mutations affecting the DNA binding, Src homology 2, and transactivation domains, including 3 novel ones. Mutation-positive but not mutation-negative subjects with HIES exhibited reduced phosphorylation of STAT3 in response to cytokine stimulation, whereas pSTAT1 activation was unaffected. Both patient groups exhibited impaired T(H)17 responses, but whereas STAT3 mutations abrogated early steps in T(H)17 differentiation, the defects in patients with HIES with normal STAT3 affected more distal steps. CONCLUSION: In this cohort of Turkish children with HIES, a majority had normal STAT3, implicating other targets in disease pathogenesis. Impaired T(H)17 responses were evident irrespective of the STAT3 mutation status, indicating that different genetic forms of HIES share a common functional outcome.

Large deletions and point mutations involving the dedicator of cytokinesis 8 (DOCK8) in the autosomal-recessive form of hyper-IgE syndrome.

BACKGROUND: The genetic etiologies of the hyper-IgE syndromes are diverse. Approximately 60% to 70% of patients with hyper-IgE syndrome have dominant mutations in STAT3, and a single patient was reported to have a homozygous TYK2 mutation. In the remaining patients with hyper-IgE syndrome, the genetic etiology has not yet been identified. OBJECTIVES: We aimed to identify a gene that is mutated or deleted in autosomal recessive hyper-IgE syndrome. METHODS: We performed genome-wide single nucleotide polymorphism analysis for 9 patients with autosomal-recessive hyper-IgE syndrome to locate copy number variations and homozygous haplotypes. Homozygosity mapping was performed with 12 patients from 7 additional families. The candidate gene was analyzed by genomic and cDNA sequencing to identify causative alleles in a total of 27 patients with autosomal-recessive hyper-IgE syndrome. RESULTS: Subtelomeric biallelic microdeletions were identified in 5 patients at the terminus of chromosome 9p. In all 5 patients, the deleted interval involved dedicator of cytokinesis 8 (DOCK8), encoding a protein implicated in the regulation of the actin cytoskeleton. Sequencing of patients without large deletions revealed 16 patients from 9 unrelated families with distinct homozygous mutations in DOCK8 causing premature termination, frameshift, splice site disruption, and single exon deletions and microdeletions. DOCK8 deficiency was associated with impaired activation of CD4+ and CD8+T cells. CONCLUSION: Autosomal-recessive mutations in DOCK8 are responsible for many, although not all, cases of autosomal-recessive hyper-IgE syndrome. DOCK8 disruption is associated with a phenotype of severe cellular immunodeficiency characterized by susceptibility to viral infections, atopic eczema, defective T-cell activation and T(h)17 cell differentiation, and impaired eosinophil homeostasis and dysregulation of IgE.

Representational oligonucleotide microarray analysis (ROMA) and comparison of binning and change-point methods of analysis: application to detection of del22q11.2 (DiGeorge) syndrome.

DiGeorge (del22q11.2) syndrome is estimated to occur in 1:4,000 births, is the most common contiguous-gene deletion syndrome in humans, and is caused by autosomal dominant deletions in the 22q11.2 DiGeorge syndrome critical region (DGCR). Multiple microarray methods have been developed recently for analyzing such copy number changes, but data analysis and accurate deletion detection remains challenging. Clinical use of these microarray methods would have many advantages, particularly when the possibility of a chromosomal disorder cannot be determined simply on the basis of history and physical examination data alone. We investigated the use of the microarray technique, representational oligonucleotide microarray analysis (ROMA), in the detection of del22q11.2 syndrome. Genomic DNA was isolated from three well-characterized cell lines with 22q11.2 DGCR deletions and from the blood of a patient suspected of having del22q11.2 syndrome, and analyzed using both the binning and change-point model algorithms. Though the 22q11.2 deletion was easily identified with either method, change-point models provide clearer identification of deleted regions, with the potential for fewer false-positive results. For circumstances in which a clear, a priori, copy-number change hypothesis is not present, such as in many clinical samples, change-point methods of analysis may be easier to interpret.

Immunoglobulin replacement therapy in children.

The benefit of immunoglobulin (IG) replacement in primary antibody deficiencies is unquestionable. Many of these congenital disorders present early in life and this therapy is often first implemented in the young. This article focuses on the indications of IG replacement in children, with an emphasis on the specific diagnostic problems encountered in this population. Also presented is an overview of the practical aspects of IG administration in the pediatric setting, including the recognition and management of adverse reactions. Finally, the advent of subcutaneous IG, a therapeutic IG modality with the potential to have a great impact on the quality of life of children with antibody deficiencies and their families, is discussed.

Allergic Diseases and Immune-Mediated Food Disorders in Pediatric Acute-Onset Neuropsychiatric Syndrome.

Background: The prevalence and impact of allergic and immune-mediated food disorders in pediatric acute-onset neuropsychiatric syndrome (PANS) are mostly unknown. Objective: We sought to explore the prevalence of atopic dermatitis (AD), asthma, allergic rhinitis (AR), IgE-mediated food allergies (FAs), and other immune-mediated food disorders requiring food avoidance in patients with PANS. In addition, to further understand the extent of food restriction in this population, we investigated the empiric use of dietary measures to improve PANS symptoms. Methods: Pediatric patients in a PANS Clinic and Research Program were given surveys regarding their caregiver burdens, allergic and food-related medical history, and whether food elimination resulted in perception of improvement of PANS symptoms. A review of health records was conducted to confirm that all responses in the survey were concordant with documentation of each patient's medical chart. Results: Sixty-nine (ages 4-20 years) of 80 subjects who fulfilled PANS criteria completed the surveys. Thirteen (18.8%) had AD, 11 (15.9%) asthma, 33 (47.8%) AR, 11 (15.9%) FA, 1 (1.4%) eosinophilic gastrointestinal disorders, 1 (1.4%) food protein-induced enterocolitis syndrome, 3 (4.3%) milk protein-induced proctocolitis syndrome, and 3 (4.3%) celiac disease. Thirty subjects (43.5%) avoided foods due to PANS; elimination of gluten and dairy was most common and was associated with perceived improvement of PANS symptoms (by parents). This perceived improvement was not confirmed with objective data. Conclusions: The prevalence of allergic and immune-mediated food disorders in PANS is similar to the general population as reported in the literature, with the exception of AR that appears to be more prevalent in our PANS cohort. More research will be required to establish whether diet or allergies influence PANS symptoms.

Persistent parvovirus-associated chronic fatigue treated with high dose intravenous immunoglobulin.

We report a 16-year-old boy with no evidence of immunodeficiency who had a 2-year history of chronic fatigue, low grade fever and slapped-cheek rash associated with chronic parvovirus B19 viremia. Prolonged intravenous immunoglobulin therapy resulted in resolution of his symptoms and viremia. Intravenous immunoglobulin may be useful in the resolution of parvovirus viremia regardless of immune status.