Case Report: Nontuberculous mycobacterial infections in children with complete DiGeorge anomaly

Children with complete DiGeorge anomaly (cDGA) have congenital athymia, resulting in severe T cell immunodeficiency and susceptibility to a broad range of infections. We report the clinical course, immunologic phenotypes, treatment, and outcomes of three cases of disseminated nontuberculous mycobacterial infections (NTM) in patients with cDGA who underwent cultured thymus tissue implantation (CTTI). Two patients were diagnosed with Mycobacterium avium complex (MAC) and one patient with Mycobacterium kansasii. All three patients required protracted therapy with multiple antimycobacterial agents. One patient, who was treated with steroids due to concern for immune reconstitution inflammatory syndrome (IRIS), died due to MAC infection. Two patients have completed therapy and are alive and well. T cell counts and cultured thymus tissue biopsies demonstrated good thymic function and thymopoiesis despite NTM infection. Based on our experience with these three patients, we recommend that providers strongly consider macrolide prophylaxis upon diagnosis of cDGA. We obtain mycobacterial blood cultures when cDGA patients have fevers without a localizing source. In cDGA patients with disseminated NTM, treatment should consist of at least two antimycobacterial medications and be provided in close consultation with an infectious diseases subspecialist. Therapy should be continued until T cell reconstitution is achieved.

Heterozygous OAS1 gain-of-function variants cause an autoinflammatory immunodeficiency

Analysis of autoinflammatory and immunodeficiency disorders elucidates human immunity and fosters the development of targeted therapies. Oligoadenylate synthetase 1 is a type I interferon-induced, intracellular double-stranded RNA (dsRNA) sensor that generates 2'-5'-oligoadenylate to activate ribonuclease L (RNase L) as a means of antiviral defense. We identified four de novo heterozygous OAS1 gain-of-function variants in six patients with a polymorphic autoinflammatory immunodeficiency characterized by recurrent fever, dermatitis, inflammatory bowel disease, pulmonary alveolar proteinosis, and hypogammaglobulinemia. To establish causality, we applied genetic, molecular dynamics simulation, biochemical, and cellular functional analyses in heterologous, autologous, and inducible pluripotent stem cell-derived macrophages and/or monocytes and B cells. We found that upon interferon-induced expression, OAS1 variant proteins displayed dsRNA-independent activity, which resulted in RNase L-mediated RNA cleavage, transcriptomic alteration, translational arrest, and dysfunction and apoptosis of monocytes, macrophages, and B cells. RNase L inhibition with curcumin modulated and allogeneic hematopoietic cell transplantation cured the disorder. Together, these data suggest that human OAS1 is a regulator of interferon-induced hyperinflammatory monocyte, macrophage, and B cell pathophysiology.

What Is Anaphylaxis? Pediatric Residents' Perception and Treatment of Anaphylactic Reactions

To assess knowledge regarding symptoms and treatment of anaphylaxis, a vignette of a child having an allergic reaction to a peanut was presented to residents in an allergy clinic. Twelve sets of clinical outcomes ranging from severe multi-organ to mild single organ involvement were described, and residents were asked if each symptom set met criteria for diagnosis of anaphylaxis, whether epinephrine should be administered acutely and prescribed at follow-up, and whether peanuts should be avoided in the future. Of cases that met the definition of anaphylaxis 28.8% were incorrectly diagnosed, in 13.6% of cases they would allow peanuts to be eaten again, and in 23.9% of cases they would not prescribe epinephrine at follow-up. In 26.1% of cases meeting criteria for acute anaphylaxis residents would not administer epinephrine. Deficits regarding the diagnosis and treatment of anaphylaxis by residents were identified, and increased educational efforts are needed.

Chronic norovirus infection in primary immune deficiency disorders: an international case series

OBJECTIVE

Predictive factors associated with clinical outcomes of chronic norovirus infection (CNI) in primary immunodeficiency diseases (PIDD) are lacking.

METHOD

We sought to characterize CNI using a multi-institutional cohort of patients with PIDD and CNI using the Clinical Immunology Society's CIS-PIDD Listserv e-mail group.

RESULTS

Thirty-four subjects (21 males and 13 females) were reported from centers across North America, Europe, and Asia. All subjects were receiving high doses (median IgG dose: 1200 mg/kg/month) of supplemental immunoglobulin therapy. Fifty-three percent had a complete absence of B cells (median B-cell count 0; range 0-139 cells/μL). Common Variable Immune Deficiency (CVID) subjects manifested a unique phenotype with B-cell lymphopenia, non O+ blood type, and villous atrophy (logistic regression model, P = 0.01). Five subjects died, all of whom had no evidence of villous atrophy.

CONCLUSION

While Norovirus (NoV) is thought to replicate in B cells, in this PIDD cohort of CNI, B-cell lymphopenia was common, indicating that the presence of B lymphocytes is not essential for CNI.

Correlation of a unique "Los Angeles" phonospirometry technique with peak expiratory flows in children with asthma

BACKGROUND

Measurement of peak expiratory flow (PEF) is recommended as part of the assessment of patients with asthma. However, there are multiple barriers in the use of PEF, even for older pediatric patients.

OBJECTIVE

Phonospirometry, as measured by the Los Angeles (LA) technique, was assessed and compared with standard PEF measurements in patients with asymptomatic and symptomatic asthma.

METHODS

A convenience sample of patients with asthma aged 8-17 years was enrolled from visits in the Allergy/Immunology Clinic and in the Emergency Department of Children's Hospital Los Angeles. The phonospirometry technique was demonstrated, and the length of time the patient repeated the syllable "lah" continuously with the same breath was measured. After a brief interval of time to recover, the patient performed conventional PEF measurement.

RESULTS

Using the first observation for each patient in our study, the Pearson correlation coefficient between phonospirometry and PEF was r = 0.67, p = .0016 for asymptomatic asthma patients and r = 0.77, p < .0001 for symptomatic asthma patients. Analysis of the first and last measurements of the symptomatic asthma patients who had multiple measurements revealed a Pearson correlation coefficient between phonospirometry and PEF at first measurement r = 0.69, p = .0008 and at the last measurement r = 0.76, p < .0001.

CONCLUSIONS

Using the LA technique, phonospirometry was shown to have a linear correlation with PEF in pediatric patients with asymptomatic and symptomatic asthma. It is simple and easily reproducible, as well as cross-cultural. This novel technique shows promise to aid the assessment of patients with acute asthma exacerbations.

Association of staphylococcal superantigen-specific immunoglobulin e with mild and moderate atopic dermatitis

OBJECTIVE

To examine the frequency of allergic sensitization to staphylococcal superantigens in young children with mild to moderate atopic dermatitis (AD).

STUDY DESIGN

AD severity was assessed with objective Scoring AD. Serum IgE to staphylococcal enterotoxin (SE) A, SEB, SEC, SED, and toxic shock syndrome toxin-1 were measured with ImmunoCAP. Comparisons between mild AD and moderate AD were performed by using logistic regressions.

RESULTS

The prevalence of allergic sensitization to staphylococcal superantigens in patients with mild and moderate AD was 38% and 63%, respectively. Allergic sensitization to staphylococcal superantigens, particularly SEA and SED, was found to be associated with moderate AD, compared with mild AD.

CONCLUSIONS

Our results suggest that allergic sensitization to staphylococcal superantigens is common even in young children with mild to moderate AD, and such sensitization may contribute to the disease severity of these patients.

Pectin anaphylaxis and possible association with cashew allergy

BACKGROUND

Inhalation of pectin has been identified as a cause of occupational asthma. However, allergic reactions to orally ingested pectin have not been reported.

OBJECTIVES

To describe a child with pectin-induced food anaphylaxis and to discuss its possible relationship to cashew allergy.

METHODS

A 3 1/2-year-old boy developed anaphylaxis once after eating cashews and later after eating a pectin-containing fruit "smoothie." He also has a history of generalized pruritus after eating grapefruit. Skin tests or radioallergosorbent tests (RASTs) were performed to pectin and other suspected food allergens.

RESULTS

The child had a positive skin prick test reaction to pectin and a high RAST reaction to cashew and pistachio. He had a low-level positive RAST reaction to grapefruit. Results of allergy tests for the other potential food allergens were negative. The pectin in the smoothie was confirmed to be of citrus origin. Review of previous case reports of pectin-induced occupational asthma revealed several patients with allergies to and cross-reactivity with cashew.

CONCLUSIONS

Ingestion, not only inhalation, of pectin can cause hypersensitivity reactions. Cashew, and possibly pistachio, allergy may be associated with pectin allergy, and the possibility of pectin allergy should be considered in cashew- or pistachio-allergic patients who have unexplained allergic reactions.

Mixed-up nuts: identification of peanuts and tree nuts by children

BACKGROUND

Peanuts and tree nuts frequently cause severe allergic reactions. Nut avoidance is the key treatment, and accurate identification of nuts is essential for successful avoidance.

OBJECTIVES

To determine the age at which nut-allergic and nonallergic children can accurately identify various nuts and whether nut-allergic children can identify nuts they should avoid.

METHODS

A "nut box" was constructed containing samples of 11 common nuts and pine nuts. Nut-allergic and nonallergic children were asked to identify the nuts, and their responses were compared and correlated by age. Nut-allergic children were asked to identify the nut(s) that they should not eat.

RESULTS

One hundred children (37 allergic and 63 nonallergic) were enrolled. The mean number of nuts correctly identified was only 2.7 per child and increased with age, but there was large variation. Fifty-nine children identified 2 or fewer nuts. Peanuts in the shell were identified most often (89% of children), followed by peanuts out of the shell (52%). Other nuts were identified less commonly, ranging from 32% for pistachios to 0% for Brazil nuts. Nut-allergic children were not better able to correctly identify tree nuts and were less able in the case of peanuts. Of the nut-allergic children, 10 (27%) could not identify the peanut or tree nut to which they were allergic.

CONCLUSIONS

In general, children, including those who are allergic to nuts, can identify few nuts. This lack of recognition could put them at increased risk for unintentional ingestion. As part of an overall educational plan, nut-allergic children should be taught not only to avoid but also to identify the nut to which they are allergic.

Latex allergy in children on home mechanical ventilation

STUDY OBJECTIVE

Determining the incidence of latex allergy in children receiving home mechanical ventilation.

BACKGROUND

The prevalence of latex allergy in the general population ranges from 0.1 to 1.0%. However, in patients with spina bifida and other chronic medical conditions associated with repeated exposure to latex, the prevalence may be as high as 60%. Children receiving home mechanical ventilation are frequently exposed to latex products. Therefore, we hypothesized that these children would be at increased risk for latex allergy.

DESIGN

Fifty-seven children receiving home mechanical ventilation (31 boys, 26 girls; mean [+/- SD] age, 7.8+/-6.6 years; range, 0.3 to 23.2 years) were enrolled. A radioallergosorbent test (RAST) for latex was administered and serum IgE levels were obtained in all patients.

RESULTS

Seventeen patients (29.8%) were found to have a positive RAST for latex. Patients with latex allergy had required mechanical ventilation for an average of 6.1+/-4.1 years vs. 5.5+/-5.4 years (p = 0.69; not significant) in those without latex allergy. Eleven of 17 patients (64.7%) had elevated serum IgE levels in the group with latex allergy vs only 14 of 40 patients (35.0%) in the group with a negative latex RAST (p = 0.04; odds ratio, 3.4).

CONCLUSION

We conclude that there is a high incidence of latex allergy in children requiring home mechanical ventilation. We speculate that screening all children receiving home mechanical ventilation may lead to the identification of patients with previously undiagnosed latex allergy and the prevention of untoward reactions from exposure to latex.

Prolonged morbidity due to delays in the diagnosis and treatment of obstructive sleep apnea in children

The inclusion of a query concerning the presence of snoring in a questionnaires used by the Allergy Service of Childrens Hospital Los Angeles (CHLA) uncovered a significant number of patients who were experiencing prolonged and discomforting symptoms owing to previously undiagnosed obstructive sleep apnea (OSA) caused by adenotonsillar hypertrophy. Of 352 patients who were discharged with a diagnosis of OSA and tonsillectomy and/or adenoidectomy at CHLA in 1996-1997, a retrospective study of the first 45 randomly selected patients who agreed to participate in a telephone interview was performed. Analysis revealed that all patients experienced severe and discomforting symptoms with all describing severe or moderate snoring. Other symptoms included chronic mouth breathing (84%), frequent otitis media (64%), sinusitis (56%), sore throat (51%), choking (47%), and daytime drowsiness (42%). Other symptoms included poor school performance, enuresis, poor appetite and/or weight gain, dysphagia, and vomiting. Symptoms began at a mean age of approximately 2 years ("birth"-9 years), and the mean period of time between the development of significant symptoms and OSA was 3.3 years (6 months-13 years). Delay between onset of significant symptoms and surgery was > 1 year in 82% of the patients, > 2 years in 51% of the patients, > 4 years in 31% of the patients, and > 6 years in 13% of the patients. Forty percent of patients were self-referred to an otolaryngologist for treatment despite their primary care physician being aware of the symptoms. These results indicate that patient with OSA experienced prolonged morbidity and delays in treatment, which is probably widespread. Physician, parent, and third-party factors were found to have contributed to the delays in treatment.

Immunologic and virologic effects of glucocorticoids on human immunodeficiency virus infection in children: a preliminary study

The immune dysfunction in human immunodeficiency virus (HIV) infection is complex and cannot be explained solely on the basis of numerical depletion of T lymphocytes. Inappropriate, uncontrolled activation of the immune system may be involved. In a test of this hypothesis, five HIV-infected children were prospectively treated with prednisone and selected immunologic and virologic indices were analyzed. Subjects had marked T lymphopenia (CD4+ T lymphocytes < 500 cells/ml) and antigenemia (serum p24 antigen > 30 pg/ml) and were free of opportunistic infections. There was a significant drop in serum p24 antigen concentrations from baseline (60.2 +/- 10.1% SEM; P < 0.005) 4 weeks after initiation of prednisone, which returned to baseline concentrations as the prednisone was tapered. Concomitant with this decrease, there was decreased expression of cell surface activation markers (HLA-DR, CD25 (interleukin 2 receptor) and CD26 (Ta-1)) in peripheral T lymphocytes. There was no significant change in either T lymphocyte subset numbers or mitogen and antigen-specific lymphoproliferation. A regulatory dysfunction of the immune system, allowing inappropriate activation of T lymphocytes, may be involved in the pathogenesis of HIV disease, and further studies involving selective immunosuppression in HIV disease are warranted.