Mark Ballow

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.

Development of the immune system in very low birth weight (less than 1500 g) premature infants: concentrations of plasma immunoglobulins and patterns of infections.

ABSTRACT. Plasma immunoglobulin concentrations of premature infants of birth weight less than 1500 g were measured longitudinally from birth to 10 months chronological age. Infants were divided into two groups based on gestational age (group I: 25–28 wk; group II: 29–32 wk). In the 1st wk of life, plasma IgG levels correlated with gestational age (r = 0.5, p < 0.001). At 3 months chronological age, the geometric mean plasma IgG levels were 60 mg/dl in group I and 104 mg/dl in group II infants. Most infants remained hypogammaglobulinemic at 6 months with seven of 11 infants in group I and 13 of 21 infants in group II having plasma IgG levels below 200 mg/dl. In the 1st wk of life, plasma IgM concentrations were 7.6 and 9.1 mg/dl in groups I and II, respectively. They rose to 41.8 and 34.7 by 8 to 10 months of life. Plasma IgA concentrations were comparable for groups I and II in the 1st wk of life (1.2 and 0.6 mg/dl, respectively), but at 1 month of age group I infants had a transient increase in IgA which was not seen in the group II infants (4.5 versus 1.9 mg/dl, respectively, p < 0.02). This transient elevation in IgA did not correlate with type or route of feeding or amounts of transfused blood. Group I and group II infants had comparable rates of infections prior to discharge from the nursery (p = 0.27). After discharge, the 43 preterm infants followed until 10 months chronological age had a significantly higher incidence of infections than 41 term infants (p = 0.04). In addition, the preterm infants had more lower respiratory infections after discharge than term infants (14 versus 2, p = 0.003), and were rehospitalized more often for infection (8 versus 0, p = 0.01). Despite severe prolonged hypogammaglobulinemia, none of the preterm infants had bacteremic illness after discharge from the nursery. This study provides normal age-group immunoglobulin values for the first 10 months of life in very small premature infants. The lack of invasive bacterial infections in this small group of preterm infants after discharge from the nursery suggests that further studies will be necessary to determine whether the hypogammaglobulinemia places these very low birth weight infants at risk for serious infection.

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.

The IgG molecule as a biological immune response modifier: Mechanisms of action of intravenous immune serum globulin in autoimmune and inflammatory disorders

Intravenous immune globulin (IVIG) is an important treatment modality in patients with humoral or B-cell immune deficiency as replacement therapy. Soon after its introduction in the early 1980s for the treatment of patients with immune deficiency, IVIG was used in the treatment of children with idiopathic thrombocytopenia purpura. Presently, more commercial IVIG is used for the treatment of autoimmune and inflammatory disorders than as replacement therapy in patients with immune deficiency. Understanding the mechanisms of action of IVIG in these autoimmune and inflammatory disorders has occupied investigators over the past 3 decades. A number of mechanisms for the immune modulation and anti-inflammatory actions of IVIG have been described, including Fc receptor blockade, inhibition of complement deposition, enhancement of regulatory T cells, inhibition or neutralization of cytokines and growth factors, accelerated clearance of autoantibodies, modulation of adhesion molecules and cell receptors, and activation of regulatory macrophages through the FcγRIIb receptor. It can now be appreciated that IVIG affects many different pathways to modulate the immune and inflammatory response. Further delineation of these pathways might lead to new treatment strategies.

Mechanisms of action of intravenous immune serum globulin in autoimmune and inflammatory diseases

Intravenous immune serum globulin (IVIG) is primarily used as replacement therapy in patients with hypogammaglobulinemia. It has been over 15 years since IVIG was first shown to be effective in the treatment of patients with autoimmune thrombocytopenic purpura. Over the past decade, IVIG has been used in the treatment of a number of autoimmune and systemic inflammatory disorders. Although the use of IVIG in many of these immune-mediated disorders was purely speculative initially, we now have a much better understanding of the mechanisms by which IVIG exerts its effects in these autoimmune diseases. IVIG exhibits a number of immune modulatory activities that are mediated by the Fc portion of IgG through the Fc gamma receptor on a variety of cell types. Although the major component in IVIG is IgG, other minor components such as solubilized lymphocyte surface membrane determinants and specific antibodies to lymphocyte surface molecules may have important immunoregulatory effects on T- and B-cell immune responses. This review discusses the proposed mechanisms of action of IVIG in autoimmune and inflammatory disorders.

Modulation of Suppressor-Cell Activity by Cimetidine in Patients with Common Variable Hypogammaglobulinemia

Because of evidence of a possible immunoregulatory role for cimetidine, an antagonist to histamine H2 receptors, we studied the effects of this drug in five adult patients with common variable hypogammaglobulinemia. Three patients had excessive suppressor-cell function associated with panhypogammaglobulinemia, whereas the other two had no apparent T-cell defects. The patients were given a one-month course of oral cimetidine (1200 mg daily in four divided doses). Subsequently, the three patients with excessive suppressor-cell function had a marked reduction in suppressor activity along with a decrease in the number of suppressor cells (T8+). One of these three had a marked rise in both in vitro immunoglobulin secretion and serum immunoglobulin concentrations, which was reversible after the drug was stopped for three months and reproducible when therapy with cimetidine was repeated. There was no difference in immunoglobulin secretion or suppressor-cell activity while taking cimetidine between the two patients with common variable hypogammaglobulinemia without excessive suppressor-cell activity and control patients with duodenal ulcers. The data suggest that H2-receptor antagonists may decrease excessive suppressor-cell activity and allow endogenous immunoglobulin production in some patients with common variable hypogammaglobulinemia.

A superantigen hypothesis for the pathogenesis of chronic hyperplastic sinusitis with massive nasal polyposis

Background The pathogenesis of chronic hyperplastic sinusitis with massive nasal polyposis is still an enigma; however, the molecular biology of this disease is beginning to become unraveled and the proinflammatory cytokines and the message and the product of these cytokines have all been identified in nasal polyps. However, the initial trigger that causes inflammation of the lateral wall of the nose to up-regulate lymphocytes and eosinophils is still unknown. Methods Thirteen patients with massive polyposis were studied. The mucus of the nasal cavities surrounding the nasal polyps was studied for both bacterial and fungal species. The lymphocytes of the nasal polyps were extracted and evaluated for the T-cell receptor, particularly, the variable β region of this receptor. Enterotoxins (superantigens) of the bacteria were studied. Finally, the histopathology of nasal polyps was studied. Results Fifty-five percent of the patients had toxin-producing Staphylococcus aureus in the nasal mucus adjacent to the polyps. Three different enterotoxins were isolated, including Staphylococcus enterotoxin A, Staphylococcus enterotoxin B, and toxic shock syndrome toxin 1. The variable B specificity for these superantigens was identified also in the polyp lymphocyte T-cell receptor. Conclusion A superantigen hypothesis for massive polyposis is suggested because the most common bacterial species found in the nasal mucus is Staphylococcus aureus. These bacteria produce enterotoxins in all of the cases studied and the corresponding variable β region of the T-cell receptor also was up-regulated in the polyp lymphocytes in cases studied thus far. These data taken together suggest that the initial injury to the lateral wall of the nose may be the result of toxin-producing Staphylococci. Superantigens (enterotoxins) may up-regulate lymphocytes to produce cytokines that are responsible for the massive up-regulation of lymphocytes, eosinophils, and macrophages, the three most common inflammatory cells found in massive nasal polyposis.

Comparison of the efficacy of IGIV-C, 10% (caprylate/chromatography) and IGIV-SD, 10% as replacement therapy in primary immune deficiency ☆: A randomized double-blind trial

A novel method of large-scale chromatography has been developed to improve recovery and purity of immunoglobulin G (IgG) from pooled plasma. The current study compares safety, toxicity and efficacy of two intravenous immunoglobulin products: a novel formulation, IGIV caprylate/chromatography (IGIV-C; Gamunex, 10%) and a licensed solvent/detergent-treated product, Gamimune N, 10% (IGIV-SD). The study, a randomized, double-blind, parallel group, therapeutic equivalence trial, was conducted at 25 treatment centers in Canada and the United States. Patients (n=172) having confirmed chronic primary immunodeficiency (PID), aged 1-75 years, and receiving IGIV therapy were enrolled. For 9 months, patients were treated with IGIV-C or IGIV-SD in accordance with the patients individualized treatment regimen utilized before study entry. The primary endpoint was the proportion of patients with >or=1 validated acute sinopulmonary infection during the treatment period. Secondary endpoints included the proportion of patients with all infections, time to first infection, annual infection rates, lung function parameters, infusion-related safety and viral safety. The annual validated infection rate in the IGIV-C group was 0.18 compared to 0.43 in the IGIV-SD group (p=0.023). Nine patients receiving IGIV-C experienced validated infections, compared to 17 patients in IGIV-SD group (p=0.06). Acute sinusitis (validated plus clinically defined) was less frequent in the IGIV-C group (p=0.012). Presence of bronchiectasis did not affect efficacy. Adverse reactions were similar in frequency and severity in both groups. No evidence of viral transmission was observed. IGIV-C appears to be superior to IGIV-SD in preventing validated sinopulmonary infections, especially acute sinusitis, in patients with PID.

Complete absence of the third component of complement in man.

A 4-yr-old female patient who has recurrent infections with encapsulated bacteria and gramnegative organisms was found to have a complete absence of total hemolytic complement and C3. Total hemolytic complement was reconstituted by the addition of functionally pure C3. With the exception of a moderately reduced homolytic C4, all other C components, measured homolytically and by radial immunodiffusion, were present in normal amounts. By Ouchterlong analysis, the patients serum contained C3b inactivator and properdin but no antigenic C3. Activation of the alternate pathway was examined by purified cobra venom factor (CVF) and inulin. Neither of these substances led to activation of properdin factor B to B. On addition of partially purified Cordis C3, in four out of four instances and with different preparations of Cordis C3, activation of factor B to B occurred in the inulin-serum-C3 mixture. In contrast, activation of factor B to B occurred only once out of four times with CVF-serum-C3 mixtures. Immune adherence was found to be normal in the patients serum and could be removed by anti-C4 antiserum of hydrazine treatment. A marked opsonic defect was present against Escherichia coli. Serum bactericidal activity against a rough strain of E. coli was also defective. The ability to mobilize an infalmmatory response was examined by Rebuck skin window technique. A delay in neutrophil migration occurred until the 6th h. In vitro lymphocyte transformation and serum immunoglobulins were normal. The proportion of peripheral blood T cells forming spontaneous sheep erythrocyte rosettes and the percentage of B cells forming EAC rosettes by the C3 receptor were normal. The significance of the absence of C3 in our patient is emphasized by the increased number of infections with encapsulated bacteria and the decreased functional biological activities of the C system, important in host defense mechanism(s).

Biosynthesis of the third component of complement (C3) in vitro by monocytes from both normal and homozygous C3-deficient humans.

Human monocytes synthesized the third component of complement (C3) up to 5 wk in vitro. Evidence for net C3 synthesis was based on (a) incorporation of 14C-labeled amino acids into C3 protein, (b) indentity of the allotype of C3 produced in vitro with that of the doners serum C3, even in the presence of carrier C3 protein of a different allotype; (c) correspondence of electrophoretic mobility, size, and subunit structure of C3 protein produced in vitro with serum C3; (d) inhibition of C3 production with cycloheximide. Monocytes from two unrelated C3-deficient patients were studied under conditions that supported C3 synthesis by normal monocytes. Serum from each of the patients contained less than 1% of the normal C3 concentration, buth their monocytes produced C3 at approximately equal to 25% of the normal rate when studied after 2 wk in vitro. The C3 produced in vitro by monocytes from one of the patients had the molecular weight of normal serum C3 and dissociated appropriately under reducing conditions. Monocytes from C3-deficient patients could not be distinguished from normals on the basis of morphology, rosetting with C3-coated erythrocytes, or rates of C2, and total protein synthesis.