Maria Luisa Romiti

Clinical Features and Follow-Up in Patients with 22q11.2 Deletion Syndrome.

OBJECTIVE To investigate the clinical manifestations at diagnosis and during follow-up in patients with 22q11.2 deletion syndrome to better define the natural history of the disease. STUDY DESIGN A retrospective and prospective multicenter study was conducted with 228 patients in the context of the Italian Network for Primary Immunodeficiencies. Clinical diagnosis was confirmed by cytogenetic or molecular analysis. RESULTS The cohort consisted of 112 males and 116 females; median age at diagnosis was 4 months (range 0 to 36 years 10 months). The diagnosis was made before 2 years of age in 71% of patients, predominantly related to the presence of heart anomalies and neonatal hypocalcemia. In patients diagnosed after 2 years of age, clinical features such as speech and language impairment, developmental delay, minor cardiac defects, recurrent infections, and facial features were the main elements leading to diagnosis. During follow-up (available for 172 patients), the frequency of autoimmune manifestations (P = .015) and speech disorders (P = .002) increased. After a median follow-up of 43 months, the survival probability was 0.92 at 15 years from diagnosis. CONCLUSIONS Our data show a delay in the diagnosis of 22q11.2 deletion syndrome with noncardiac symptoms. This study provides guidelines for pediatricians and specialists for early identification of cases that can be confirmed by genetic testing, which would permit the provision of appropriate clinical management.

Post-Natal Ontogenesis of the T-Cell Receptor CD4 and CD8 Vβ Repertoire and Immune Function in Children with DiGeorge Syndrome

DiGeorge syndrome (DGS) is a congenital disorder characterized by typical facial features, hypoparatyroidism, conotruncal cardiac defects and thymic hypoplasia. Although there are some reports addressing lymphocytes counts and function in DGS children over time, few data have been reported on the T-cell receptor Vβ (TCRBV) repertoire in relation to disease progression. The aim of this study was to evaluate the degree and nature of immunodeficiency and to investigate a possible correlation to clinical findings.We used third complementary region (CDR3) size spectratyping as a tool for monitoring T-cell repertoire diversity in 7 DGS’s children. The rate of thymic output, the phenotype and function of peripheral T-cells and the humoral immunity were also investigated. At baseline a profound alteration of the TCR repertoire was noted, mainly in the CD8+ T-cells, in DGS patients when compared to a control group. Furthermore, analysis of thymic output showed a significant decrease in TCR rearrangement excision circles (TRECs) levels in the patient group. Immunoglobulin abnormalities were also detected. The observed TCR repertoire alterations, although not statistically significant, may suggest an increased susceptibility to infections. A parallel increase in the TCR repertoire diversity and clinical improvement occurred during the follow-up. Our results confirm that the extent of immunodeficiency is highly variable and could improve through childhood, and indicate that TCR repertoire may be a useful marker to clinically monitor thymic function in this primary immunodeficiency.

Kinetics of the T-cell receptor CD4 and CD8 Vβ repertoire in HIV-1 vertically infected infants early treated with HAART

ObjectivesTo determine the kinetics and the relationship between the T-cell receptor Vβ (TCRBV) complementary determining region 3 length, the CD4 T-cell count and HIV viral load changes in HIV-1 infected infants treated early with highly active antiretroviral therapy (HAART) during 1 year of follow-up. DesignTwo HIV-1 vertically infected infants, two HIV-1 vertically exposed uninfected and two healthy controls were analysed by spectratyping. Evaluation of viral load, CD4 naive and memory cell counts and a proliferation test were also carried out. MethodsTwenty-six families and subfamilies of the TCR on CD4 and CD8 T cells were analyzed by spectratyping. Flow cytometric analysis on peripheral blood mononuclear cells for CD4CD45Ra, CD4CD45Ro, CD8CD38, proliferation tests and plasma viral load measurements were performed at baseline, 1, 6 and after 12 months of therapy. ResultsHAART induced a marked reduction of viral load in both HIV-1 infected infants and an increase to normal CD4 T-cell count in the symptomatic infant. At baseline the TCRBV family distribution in the majority of CD8 and a few of the CD4 T cells was highly perturbed, with several TCRBV families showing a monoclonal/oligoclonal distribution. During HAART a normalization of the TCR repertoire in both CD8 and CD4 subsets occurred. TCR repertoire normalization was associated with a good virological and immunological response. ConclusionThese results suggest that complete and early virus replication control as a result of early HAART leads to a marked reduction of T-cell oligoclonality and is an essential prerequisite to the development of a polyclonal immune response in HIV-1 infected infants.

Therapeutic DNA Vaccination of Vertically HIV-Infected Children: Report of the First Pediatric Randomised Trial (PEDVAC)

Subjects Twenty vertically HIV-infected children, 6–16 years of age, with stable viral load control and CD4+ values above 400 cells/mm3. Intervention Ten subjects continued their ongoing antiretroviral treatment (ART, Group A) and 10 were immunized with a HIV-DNA vaccine in addition to their previous therapy (ART and vaccine, Group B). The genetic vaccine represented HIV-1 subtypes A, B and C, encoded Env, Rev, Gag and RT and had no additional adjuvant. Immunizations took place at weeks 0, 4 and 12, with a boosting dose at week 36. Monitoring was performed until week 60 and extended to week 96. Results Safety data showed good tolerance of the vaccine. Adherence to ART remained high and persistent during the study and did not differ significantly between controls and vaccinees. Neither group experienced either virological failure or a decline of CD4+ counts from baseline. Higher HIV-specific cellular immune responses were noted transiently to Gag but not to other components of the vaccine. Lymphoproliferative responses to a virion antigen HIV-1 MN were higher in the vaccinees than in the controls (p = 0.047), whereas differences in reactivity to clade-specific Gag p24, RT or Env did not reach significance. Compared to baseline, the percentage of HIV-specific CD8+ lymphocytes releasing perforin in the Group B was higher after the vaccination schedule had been completed (p = 0.031). No increased CD8+ perforin levels were observed in control Group A. Conclusions The present study demonstrates the feasibility, safety and moderate immunogenicity of genetic vaccination in vertically HIV-infected children, paving the way for amplified immunotherapeutic approaches in the pediatric population. Trial registration clinicaltrialsregister.eu _2007-002359-18 IT

Safety and immunogenicity of a monovalent MF59®-adjuvanted A/H1N1 vaccine in HIV-infected children and young adults.

BACKGROUND This Phase IV study evaluated the safety and immunogenicity of a two-dose, MF59®-adjuvanted (Novartis Vaccines, Marburg, Germany), monovalent, A/H1N1 pandemic influenza vaccination schedule in Human Immunodeficiency Virus (HIV) positive children and young adults. METHODS A total of 83 children infected with HIV-1, and 37 non-immunocompromised, age-matched controls were enrolled. All participants received two vaccine doses administered three weeks apart. Antibody responses were assessed by haemagglutination assay at baseline, three weeks after each vaccine dose, and six months after immunization. Vaccines were evaluated according to European influenza vaccine licensure criteria. RESULTS The investigational vaccine was well tolerated. After the first vaccine dose, seroconversion rates were significantly lower in HIV-positive patients (60%) than controls (82%), with GMTs of 419 and 600, respectively. No significant differences in seroconversion rates were observed between the two study groups in response to the second vaccine dose. Persisting antibody titers were similar for both HIV-positive and non-infected controls, six months after immunization. CONCLUSION One dose of MF59-adjuvanted vaccine was sufficient to provide adequate levels of seroprotection against A/H1N1 influenza disease in HIV-positive children. However, a two-dose vaccination schedule may be optimal for this population.

Delayed early antiretroviral treatment is associated with an HIV-specific long-term cellular response in HIV-1 vertically infected infants

Antiviral T-cell immune responses appear to be crucial to control HIV replication. Infants treated before the third month of life with highly active antiretroviral treatment (HAART) did not develop a persistent HIV-specific immune response. We evaluated how delayed initiation of HAART after 3 months of age influences the development of HIV-1-specific T-cell responses during long-term follow-up in 9 HIV-1 vertically infected infants. These data suggest that a longer antigenic stimulation, due to a larger window for therapeutic intervention with HAART, is associated with the establishment of a persistent specific HIV immune response resulting in a long-term viral control of vertically infected infants.

Successful simplification of protease inhibitor-based HAART with triple nucleoside regimens in children vertically infected with HIV

Objective:To assess the virological, immunological and metabolic effects of switching from an efficacious first-line protease inhibitor (PI)-based HAART to a simplified triple nucleoside reverse transcriptase inhibitor (NRTI) regimen in children vertically infected with HIV. Design:Prospective, open-label, before–after study of 20 vertically infected children with at least 12 consecutive months of undetectable viral load under a PI-based HAART and no previous history of NRTI treatment. Methods:At study entry, HAART was shifted to a triple-NRTI combination. Results:The children were aged 2 to 18 years (median, 7.9) and were followed for 96 weeks. All were receiving a PI-based regimen for an average duration of 4 years before enrollment. At study entry, 12 patients (60%) switched to abacavir, 5 (25%) to lamivudine; 2 (10%) to zidovudine and 2 to didanosine (10%). All but one patient maintained plasma HIV RNA < 50 copies/ml during the entire follow-up. No immunological failure was observed at week 96. A trend of normalization (P < 0.001) of T cell receptor Vβ families of the CD8 cell subset was detected in 19/20 (95%), with an increased HIV-specific CD8 T cell response (P < 0.01) in 17/20 (85%). Dyslipidaemia significantly improved during the follow up (P < 0.001). No new cases of lipodystrophy were detected. Conclusions:Switching to triple-NRTI regimens in selected HIV-infected children with an extremely low likelihood of harbouring nucleoside-associated mutations maintains viral suppression and immunological function, improving metabolic abnormalities and the effort to take medication for up to 96 weeks.

Role of reduced intensity conditioning in T-cell and B-cell immune reconstitution after HLA-identical bone marrow transplantation in ADA-SCID

The treatment of choice for severe combined immunodeficiency is bone marrow transplantation from an HLA-identical donor sibling without conditioning. However, this may result in low donor stem cell chimerism, leading to reduced long-term immune reconstitution. We compared engraftment, metabolic, and T-cell and B-cell immune reconstitution of HLA-identical sibling bone marrow transplantation performed in 2 severe combined immunodeficiency infants with adenosine deaminase deficiency from the same family treated with or without a reduced intensity conditioning regimen (busulfan/fludarabine). Only the patient who received conditioning showed a stable mixed chimerism in all lineages, including bone marrow myeloid and B cells. The use of conditioning resulted in higher thymus-derived naïve T cells and T-cell receptor excision circles, normalization of the T-cell repertoire, and faster and complete B-cell and metabolic reconstitution. These results suggest the utility of exploring the use of reduced intensity conditioning in bone marrow transplantation from HLA-identical donor in severe combined immunodeficiency to improve long-term immune reconstitution.

Role of immunity in maternal—infant HIV-1 transmission

Factors influencing human immunodeficiency virus type 1 (HIV‐1) mother‐to‐child transmission include both immunological and virological parameters: higher viral loads have been associated with clinical stage of HIV‐1‐infected individuals as well as higher risk of mother‐to‐child transmission. Furthermore, we have shown that transmitting mothers more frequently harbour HIV‐1 isolates with rapid/high syncytium‐inducing (SI) biological phenotype than non‐transmitting mothers do. Genetically homogeneous virus populations have been found in HIV‐1‐infected children at birth, in contrast to the heterogeneous virus populations often found in their infected mothers. This observation suggests that a few virus variants are transmitted or initially are replicating in the child. By comparing the HIV‐1 gp120 V3 region of sequentially obtained samples from infected children with samples obtained from their mothers at delivery we found, however, that multiple variants of HIV‐1 with different outgrowth kinetics can be transmitted. In addition, we have obtained results indicating an impaired ability of the immune response to adapt to the sequence evolution of HIV‐1 in transmitting mothers, as assessed by measuring serum reactivities to peptides representing selected yet closely related V3 sequences. By analysing the presence of antibodies in maternal serum at delivery, which neutralize autologous isolates as well as other primary virus isolates, we have indications that a protective immunity in HIV‐1 mother‐to‐child transmission might exist. Immunotherapy has been assessed in infected adult individuals by passive immunization with a variety of HIV‐1‐specific antibody products. Data from these studies indicated a differential response to therapy according to the stage of the disease. Active vaccine strategies, including envelope glycoproteins, pursued so far in seronegative adult subjects have shown limitations because broadly neutralizing antibodies, such as can be found in infected individuals, have not been evoked. Further investigations are therefore needed to give support for the potential use of either passive and/or active immunization for the prevention of HIV‐1 mother‐to‐child transmission.

Switching from protease inhibitor-based-HAART to a protease inhibitor-sparing regimen is associated with improved specific HIV-immune responses in HIV-infected children.

To evaluate the effects of switching from successful long-term protease inhibitor (PI)-based HAART to a three nucleoside reverse transcriptase inhibitor PI-sparing regimen, viral load quantification, HIV-specific lymphoproliferative assay and T-cell receptor (TCR) spectratyping were performed during 96 weeks of simplification follow-up in 19 HIV-infected children. Our data showed that simplification of therapeutic strategies acts positively on immune competence in HIV paediatric patients. Our children maintained viral suppression, increased lymphoproliferative responses and normalized TCRBV repertoire on the CD8 subset.