Andrea Martín-Nalda

Prospective study of renal function in HIV-infected pediatric patients receiving tenofovir-containing HAART regimens

Aim:To describe the impact of tenofovir disoproxil fumarate (TDF) use on renal function in HIV-infected pediatric patients. Design:It is a prospective, multicenter study. The setting consisted of five third-level pediatric hospitals in Spain. The study was conducted on patients aged 18 years and younger who had received TDF for at least 6 months. The intervention was based on the study of renal function parameters by urine and serum analyses. The main outcome measures were renal function results following at least 6 months of TDF therapy. Results:Forty patients were included (32 were white and 26 were diagnosed with AIDS). Median (range) duration of TDF treatment was 77 months (16–143). There were no significant changes in the estimated creatinine clearance. Urine osmolality was abnormal in eight of 37 patients, a decrease in tubular phosphate absorption was documented in 28 of 38 patients, and 33 of 37 patients had proteinuria. A statistically significant decrease in serum phosphate and potassium concentrations was observed during treatment (P = 0.005 and P = 0.003, respectively), as well as a significant relationship between final phosphate concentration and tubular phosphate absorption (P = 0.010). A negative correlation was found between phosphate concentration and time on TDF. Conclusions:TDF use showed a significant association with renal tubular dysfunction in HIV-infected pediatric patients. Periodic assessment of tubular function may be advisable in the follow-up of this population.

Intravenous and Subcutaneous Immunoglobulin Replacement: A Two-Way Road. Optimizing Healthcare Quality in Patients with Primary Immunodeficiencies

PurposeTo evaluate the alternate use of subcutaneous immunoglobulin (SCIG) and intravenous immunoglobulin (IVIG) in patients with primary immunodeficiencies (PID) in a third-level Pediatric University Hospital.MethodsRetrospective study of all patients receiving SCIG from 2006 to 2012. Data collected included demographics, date SCIG was started, date of switch to IVIG and reasons, administration tolerance, and related adverse events. Effectiveness was defined as the lack of severe infections.ResultsTwenty-three patients (15 male, 8 female) with PID were studied. SCIG was initiated at a median age of 14.2 years (8.4 months-25.7 years) and median duration on SCIG treatment was 41 months (4-68). Nine patients (39.1%) temporarily switched from SCIG to IVIG for the following reasons: vacation (8), administration issues (1), and transient need for immunomodulatory therapy (1). A mean of 5.2 IVIG infusions/patient (SD=2.86) was administered while on SCIG. IVIG-related adverse events were documented in 3 patients with 6 infusions. Eight (34.8%) patients definitively discontinued SCIG use for the following reasons: convenience (5), adverse effects (1), coagulopathy (1), and autoimmune thrombocytopenia (1). There were no severe infections requiring hospital admission in any patient during the study period.ConclusionsAlternating SCIG and IVIG use in patients with PID was associated with considerable advantages in terms of convenience for the patients and their caregivers, while maintaining the effectiveness and safety of this therapy. Healthcare units treating these patients should show flexibility with this dual therapy in order to optimize patients’ quality of life.

From Severe Combined Immunodeficiency to Omenn syndrome after hematopoietic stem cell transplantation in a RAG1 deficient family

Background:  Mutations in RAG genes cause a spectrum of severe immunodeficiencies ranging from Severe Combined Immunodeficiency (SCID) T‐B‐NK+ to Omenn syndrome (OS) through intermediate phenotypes, even for the same alteration. Nowadays, hematopoietic stem cell transplantation (HSCT) is the unique curative treatment available.

Laboratory evaluation of the IFN-γ circuit for the molecular diagnosis of Mendelian susceptibility to mycobacterial disease

Abstract The integrity of the interferon (IFN)-γ circuit is necessary to mount an effective immune response to intra-macrophagic pathogens, especially Mycobacteria. Inherited monogenic defects in this circuit that disrupt the production of, or response to, IFN-γ underlie a primary immunodeficiency known as Mendelian susceptibility to mycobacterial disease (MSMD). Otherwise healthy patients display a selective susceptibility to clinical disease caused by poorly virulent mycobacteria such as BCG (bacille Calmette-Guérin) vaccines and environmental mycobacteria, and more rarely by other intra-macrophagic pathogens, particularly Salmonella and M. tuberculosis. There is high genetic and allelic heterogeneity, with 19 genetic etiologies due to mutations in 10 genes that account for only about half of the patients reported. An efficient laboratory diagnostic approach to suspected MSMD patients is important, because it enables the establishment of specific therapeutic measures that will improve the patient’s prognosis and quality of life. Moreover, it is essential to offer genetic counseling to affected families. Herein, we review the various genetic and immunological diagnostic approaches that can be used in concert to reach a molecular and cellular diagnosis in patients with MSMD.

HYPOGAMMAGLOBULINEMIA IN A 12-YEAR-OLD PATIENT WITH JACOBSEN SYNDROME

Jacobsen syndrome (JS) is a rare congenital disorder with an estimated prevalence of 1 in 100 000 newborns, caused by partial deletion of the long arm of chromosome 11 (del(11)(q23)), which is a de novo event in 85% of cases. The main clinical and analytic findings of JS are reviewed elsewhere. The association of JS with an immune alteration (humoral and/or cellular) has been described only sporadically. A boy with JS, currently 12 years of age, is herein described. Diagnosis was established based on clinical findings (thrombocytopenia, umbilical and bilateral inguinal hernia, left hydrocele, right cryptorchidism, severe mental retardation, cardiac alterations, corneal opacity, facial dysmorphism and clinodactyly). Karyotiping and comparative genomic hybridisation, identified a duplication of the 11q22-q23 region and a deletion in the 11q24.3-qter region. Chromosome study of the parents was normal and the anomaly was considered a de novo event. Since infancy, the patient had presented chronic diarrhoea and multiple respiratory tract infections that required various hospitalisations and antibiotic therapy. At the age of 5, immunologic study demonstrated persistent hypogammaglobulinemia with present but poor response to some vaccines and lymphopenia with no significant cell function alterations (Table 1). Therefore, regular intravenous immunoglobulin (IVIG) therapy was started and the patient experienced an evident clinical improvement with regard to infections. Currently, he remains dependent on his care givers for daily living and he has had no other complications related to the syndrome. The association of immunologic alterations with JS is uncommon and poorly defined. Sirvent et al. described two JS patients with a predominantly humoral defect, as in our case, but without an IgG deficit or the need for IG therapy. Von Bubnof et al. presented a single adult JS patient with affected cell

Clinical and structural impact of mutations affecting the residue Phe367 of FOXP3 in patients with IPEX syndrome.

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a monogenic autoimmune disease characterized by early-onset life-threatening multisystemic autoimmunity. This rare hereditary disorder is caused by loss-of-function mutations in the gene encoding the forkhead box P3 (FOXP3) transcription factor, which plays a key role in the differentiation and function of CD4(+)CD25(+) natural regulatory T cells (Tregs), essential for the establishment and maintenance of natural tolerance. We identified a novel mutation in the FOXP3 gene affecting the Phe367 residue of the protein (F367V) in a family with three male siblings affected by IPEX. Two other mutations affecting the FOXP3 Phe367 residue (F367L and F367C) have been described previously. This unique situation of three mutations affecting the same residue in FOXP3 led us to study the molecular impact of these mutations on the structure of FOXP3 protein. Structure analysis showed that Phe367 is involved in a rich interaction network related to both monomer and dimer structure stabilization, and is crucial for FOXP3 regulatory activity. The relevance of this location is confirmed by the results of SIFT and PolyPhen-2 pathogenicity predictions for F367V mutation. In summary, as assessment of the pathogenicity of a novel mutation is crucial to achieve a proper molecular diagnosis, we analysed the impact of mutations affecting the Phe367 residue using a combined approach that provides a mechanistic view of their pathogenic effect.

Cystatin C: A Marker for Inflammation and Renal Function Among HIV-infected Children and Adolescents.

Background: Renal disease is a leading cause of morbidity in HIV-infected adults in the highly active antiretroviral therapy (HAART) era. Cystatin C has been proposed as a more sensitive marker of renal function, but it may be affected by ongoing inflammation. We aimed to study the cystatin C levels in a cohort of HIV-infected pediatric patients at 3 Spanish centers. Methods: This is a multicenter cross-sectional observational study. Renal function was assessed by means of first morning urine protein/creatinine and albumin/creatinine ratios and creatinine-estimated glomerular filtration rates (GFRs), together with the following inflammation markers: cystatin C, reactive C protein, &bgr;-2-microglobulin and 25(OH)-vitamin D levels. A control group of healthy children and adolescents was used. Results: Eighty-three patients (51 females, median age: 13.3 years; 32 males, median age: 13.6 years) and 44 controls (24 females, median age: 12.2 years; 20 males, median age: 10.9 years) were included. Among the former, mean CD4 cell count was 860/mm3, 29(35%) patients had a previous AIDS diagnosis, 73(88%) were on HAART and HIV viremia was undetectable in 61(73%). No differences in cystatin C levels were observed between the 2 groups. In HIV-infected patients, cystatin C levels correlated with GFR (r = −0.27; P = 0.01), age at first HAART (r = −0.21; P = 0.05), and &bgr;-2-microglobulin (r = 0.569; P < 0.01). In multivariate analysis, lower GFR (P = 0.014) and higher &bgr;-2-microglobulin levels (P = 0.001) remained as independent risk factors for higher cystatin C values. Conclusions: Cystatin C values were associated with GFR and &bgr;-2-microglobulin. Cystatin C may be useful as a marker of renal function in HIV-infected pediatric patients, independently of ongoing inflammation or viremia.

Es útil el cribado familiar en el déficit selectivo de inmunoglobulina A

INTRODUCTION Selective immunoglobulin A deficiency (SIgAD), the most common primary immunodeficiency, is often asymptomatic. High rates of familial clustering have been described in SIgAD, but the causative genetic defect and mechanism of inheritance are unknown. OBJECTIVES To determine whether familial SIgAD cases show more severe clinical and immunological characteristics than sporadic ones; to investigate the utility of screening first-degree relatives (FDRs) of these patients, and to determine whether symptoms in affected family members are important enough to justify screening. PATIENTS AND METHODS Descriptive, cross-sectional study (October 2010-September 2011) of all patients with SIgAD and followed up in our center. Demographic, clinical, and analytical data were reviewed. A familial case was defined as an SIgAD patient with at least one affected FDR. RESULTS Of the 130 participants, 42 were SIgAD patients and 88 FDR. There were 13 (31%) familial cases and and 14 (16%) affected FDRs. Six family members had to be analyzed in order to detect one affected one. There were no clinical differences between familial and sporadic SIgAD cases. The percentages of intestinal disease (p=001, OR=9.57, 95%CI 2.59-35.3), hospitalizations (p=045, OR=4.01; 95%CI 1.10-14.67], and need for chronic treatment (p=006, OR=5.5; 95%CI 1.57-19.54) were higher in affected FDRs than in unaffected ones. CONCLUSIONS The symptoms were not more severe in familial than sporadic SIgAD cases. Nonetheless, the elevated prevalence of affected FDRs with significant morbidity may justify routine screening of close family members of these patients.

TNFAIP3 haploinsufficiency is the cause of autoinflammatory manifestations in a patient with a deletion of 13Mb on chromosome 6

There is scarce literature about autoinflammation in syndromic patients. We describe a patient who, in addition to psychomotor and growth delay, presented with fevers, neutrophilic dermatosis, and recurrent orogenital ulcers. Comparative Genomic Hybridization (CGH) array permitted to identify a 13.13Mb deletion on chromosome 6, encompassing 53 genes, and including TNFAIP3 gene (A20). A20 is a potent inhibitor of the NF-kB signalling pathway and restricts inflammation via its deubiquitinase activity. Western blotting and immunoprecipitation assays showed decreased A20 expression and increased phosphorylation of p65 and IkBa. Patients cells displayed increased levels of total K63-linked ubiquitin and increased levels of ubiquitinated RIP and NEMO after stimulation with TNF. We describe the molecular characterization of an autoinflammatory disease due to a large chromosomal deletion and review the phenotypes of patients with A20 haploinsufficiency. CGH arrays should be the first diagnostic method for comprehensive analysis of patients with syndromic features and immune dysregulation.

Age-specific pediatric reference ranges for immunoglobulins and complement proteins on the Optilite™ automated turbidimetric analyzer

Measurement of immunoglobulins and complement proteins are frontline tests used in the assessment of immune system integrity, and reference values can vary with age. Their measurement provides an insight into the function of the innate and adaptive immune systems.