Congenital cytomegalovirus infection in a preterm infant with 22q11.2 deletion syndrome and immunological abnormalities

The 22q11.2 deletion syndrome has many complications; one of them is immunodeficiency. However, the time of onset and the degree of immunodeficiency can vary. We report a case of a preterm infant with congenital cytomegalovirus infection complicated with 22q11.2 deletion syndrome and immunological abnormalities. Ultrasonography revealed pulmonary atresia, ventricular septal defect, major aortopulmonary collateral artery, and thymic hypoplasia. His serum chemistry tests on admission revealed immunoglobulin G, A, and M levels of 1,547 mg/dL, 70 mg/dL, and 274 mg/dL, respectively. A surface antigen analysis of the peripheral lymphocytes using flow cytometry revealed the following: relatively low CD4-positive T-cell levels (18.1%; 1,767/μL), very high CD8-positive T-cell levels (58.9%; 5,751/μL), and CD4/CD8 ratio of 0.31. The level of T-cell receptor excision circles was relatively low at 17.5 copies/μL. After birth, the CD8-positive T-cell level began to gradually decrease, whereas the CD4/CD8 ratio began to increase. Thrombocytopenia, neutropenia, and skin petechiae were observed on admission. However, the condition improved. Treatment for congenital cytomegalovirus infection was not provided due to the absence of viremia. Unfortunately, the patient died suddenly on the 158th day of life, and the cause of death was unknown. To the best of our knowledge, no association between 22q11 deletion syndrome and cCMV has been described in the recent medical literature. According to the calculation, around one newborn infant who have both 22q11 deletion syndrome and cCMV infection will be born each year in Japan. Healthcare providers should pay more attention to this medical situation in the future.

A complementary approach for genetic diagnosis of inborn errors of immunity using proteogenomic analysis

Advances in next-generation sequencing technology have identified many genes responsible for inborn errors of immunity (IEI). However, there is still room for improvement in the efficiency of genetic diagnosis. Recently, RNA sequencing and proteomics using peripheral blood mononuclear cells (PBMCs) have gained attention, but only some studies have integrated these analyses in IEI. Moreover, previous proteomic studies for PBMCs have achieved limited coverage (approximately 3000 proteins). More comprehensive data are needed to gain valuable insights into the molecular mechanisms underlying IEI. Here, we propose a state-of-the-art method for diagnosing IEI using PBMCs proteomics integrated with targeted RNA sequencing (T-RNA-seq), providing unique insights into the pathogenesis of IEI. This study analyzed 70 IEI patients whose genetic etiology had not been identified by genetic analysis. In-depth proteomics identified 6498 proteins, which covered 63% of 527 genes identified in T-RNA-seq, allowing us to examine the molecular cause of IEI and immune cell defects. This integrated analysis identified the disease-causing genes in four cases undiagnosed in previous genetic studies. Three of them could be diagnosed by T-RNA-seq, while the other could only be diagnosed by proteomics. Moreover, this integrated analysis showed high protein-mRNA correlations in B- and T-cell-specific genes, and their expression profiles identified patients with immune cell dysfunction. These results indicate that integrated analysis improves the efficiency of genetic diagnosis and provides a deep understanding of the immune cell dysfunction underlying the etiology of IEI. Our novel approach demonstrates the complementary role of proteogenomic analysis in the genetic diagnosis and characterization of IEI.

Clinical Courses of IKAROS and CTLA4 Deficiencies: A Systematic Literature Review and Retrospective Longitudinal Study

IKAROS and CTLA4 deficiencies are inborn errors of immunity and show similar clinical phenotypes, including hypogammaglobulinemia and autoimmune diseases (ADs). However, the differences in clinical features and pathogenesis of these are not fully understood. Therefore, we performed systematic literature reviews for IKAROS and CTLA4 deficiencies. The reviews suggested that patients with IKAROS deficiency develop AD earlier than hypogammaglobulinemia. However, no study assessed the detailed changes in clinical manifestations over time; this was likely due to the cross-sectional nature of the studies. Therefore, we conducted a retrospective longitudinal study on IKAROS and CTLA4 deficiencies in our cohort to evaluate the clinical course over time. In patients with IKAROS deficiency, AD and hypogammaglobulinemia often develop in that order, and AD often resolves before the onset of hypogammaglobulinemia; these observations were not found in patients with CTLA4 deficiency. Understanding this difference in the clinical course helps in the clinical management of both. Furthermore, our results suggest B- and T-cell-mediated ADs in patients with IKAROS and CTLA4 deficiencies, respectively.

Dysregulation of the Intestinal Microbiome in Patients With Haploinsufficiency of A20

Introduction

Haploinsufficiency of A20 (HA20) is a form of inborn errors of immunity (IEI). IEIs are genetically occurring diseases, some of which cause intestinal dysbiosis. Due to the dysregulation of regulatory T cells (Tregs) observed in patients with HA20, gut dysbiosis was associated with Tregs in intestinal lamina propria.

Methods

Stool samples were obtained from 16 patients with HA20 and 15 of their family members. Infant samples and/or samples with recent antibiotics use were excluded; hence, 26 samples from 13 patients and 13 family members were analyzed. The 16S sequencing process was conducted to assess the microbial composition of samples. Combined with clinical information, the relationship between the microbiome and the disease activity was statistically analyzed.

Results

The composition of gut microbiota in patients with HA20 was disturbed compared with that in healthy family members. Age, disease severity, and use of immunosuppressants corresponded to dysbiosis. However, other explanatory factors, such as abdominal symptoms and probiotic treatment, were not associated. The overall composition at the phylum level was stable, but some genera were significantly increased or decreased. Furthermore, among the seven operational taxonomic units (OTUs) that increased, two OTUs, Streptococcus mutans and Lactobacillus salivarius, considerably increased in patients with autoantibodies than those without autoantibodies.

Discussion

Detailed interaction on intestinal epithelium remains unknown; the relationship between the disease and stool composition change helps us understand the mechanism of an immunological reaction to microorganisms.

An infant with X-linked anhidrotic ectodermal dysplasia with immunodeficiency presenting with Pneumocystis pneumonia: A case report

Pneumocystis jirovecii pneumonia associated with primary immunodeficiency should be considered in infants with slowly progressing cyanosis, even without fever or respiratory symptoms. Genetic counseling is crucial for incontinentia pigmenti families in advance of pregnancy because lethal infections can occur before the diagnosis of X-linked anhidrotic ectodermal dysplasia with immunodeficiency.

Nonosmotic secretion of arginine vasopressin and salt loss in hyponatremia in Kawasaki disease

BACKGROUND

The precise mechanism of hyponatremia in Kawasaki disease (KD) remains elusive because assessment of volume status based on serial changes in body weight is lacking in previous reports.

METHODS

Seventeen patients who were diagnosed with KD and hyponatremia (serum sodium levels <135 mmol/L) were analyzed. Volume status was assessed based on serial changes in body weight. Plasma arginine vasopressin (ADH), urine electrolytes, and serum cytokine levels were measured on diagnosis of hyponatremia. An increase in body weight by >3% was defined as hypervolemia and a decrease in body weight by >3% was defined as hypovolemia.

RESULTS

The volume status was hypervolemic in three patients (18%), euvolemic in 14 (82%), and hypovolemic in none (0%). Five (29%) patients were diagnosed with "syndrome of inappropriate secretion of antidiuretic hormone" (SIADH) and no patients were diagnosed with hypotonic dehydration. The contribution of decreased total exchangeable cations (salt loss) to hyponatremia (5.9% [interquartile range, 4.3%, 6.7%]) was significantly larger than that of increased total body water (-0.7% [-1.8%, 3.1%]) (P = 0.004). Serum interleukin-6 levels were elevated in all of the nine patients who were evaluated. Among the 12 (71%) patients who did not meet the criteria of SIADH and hypotonic dehydration, plasma ADH levels were inappropriately high in ten patients. These patients were also characterized by euvolemic or hypervolemic hyponatremia and salt loss, which might be compatible with a diagnosis of SIADH.

CONCLUSIONS

Our study shows that hyponatremia in KD is euvolemic or hypervolemic and is associated with nonosmotic secretion of ADH and salt loss in the majority of patients.

2334. Risk Factors of Multidrug-Resistant Gram-Negative Bacterial Bloodstream Infections in Children’s Hospitals in Japan

Background

Although multidrug-resistant (MDR) Gram-negative bacilli (GNB) are a serious and growing concern worldwide, the epidemiological data on children are still limited. Our aim was to evaluate the risk factors for MDR GNB bloodstream infections (BSI) in children.

Methods

Patients with GNB BSI were enrolled between April 2010 and March 2017 at eight children’s hospitals in Japan. Clinical and microbiological data were collected retrospectively. The 2012 criteria of the Centers for Disease Control and Prevention were used to define MDR. MDR and non-MDR GNB BSI were then compared in terms of risk factors.

Results

In total, 629 GNB BSI cases were identified. The median age and proportion of males was 2 years (IQR 0.3–8.7) and 50.7%, respectively. Underlying diseases were found in 94% of the patients. The proportion of GNB BSI cases developing after >48 hours from admission was 76.2%. The most common GNB was Escherichia coli (29.3%, 184/629), followed by Klebsiella pneumoniae (19.7%, 124/629) and Pseudomonas aeruginosa (16.4%, 103/629). MDR comprised 24.5% (154/629) of cases. The MDR rate for E. coli, K. pneumoniae, and P. aeruginosa was 44.0% (81/184), 23.4% (29/124), and 16.5% (17/103), respectively. The coverage rate of the initial empiric therapy for the MDR and non-MDR GNB BSI cases was 60.4% and 83.4%, respectively (P < 0.001). The all-cause mortality rate at 28 days of GNB BSI was 10.7% (67/629), 13.6% (21/154), and 9.7% (46/475) for MDR- and non-MDR GNB BSI, respectively (P = 0.167). The all-cause mortality rate at 28 days was 10.4% (14/135) and 7.7% (27/351) for MDR and non-MDR Enterobacteriaceae BSI (P = 0.341) and 41.2% (7/17) and 18.6% (16/86) for MDR- and non-MDR P. aeruginosa BSI, respectively (P = 0.056). Multivariate logistic regression analysis showed that MDR GNB BSI was independently associated with anticarcinogenic drug use within 30 days (OR: 43.90; 95% CI: 4.69–411.08), older age (OR: 1.05; 95% CI: 1.02–1.09), and admission to the neonatology ward (OR 0.019; 95% CI: 0.005–0.076).

Conclusion

One-fourth of GNB BSI cases were MDR. Anticarcinogenic drug use and older age were risk factors for MDR GNB BSI in children’s hospitals. MDR P. aeruginosa infections were associated with higher all-cause mortality.

Disclosures

All authors: No reported disclosures.