Severe Immunodeficiency Research Articles

CD4:CD8 lymphocyte ratio as a quantitative measure of immunologic health in HIV-1 infection: findings from an African cohort with prospective data.

In individuals with human immunodeficiency virus type 1 (HIV-1) infection, CD4:CD8 lymphocyte ratio is often recognized as a quantitative outcome that reflects the critical role of both CD4+ and CD8+ T-cells in HIV-1 pathogenesis or disease progression. Our work aimed to first establish the dynamics and clinical relevance of CD4:CD8 ratio in a cohort of native Africans and then to examine its association with viral and host factors, including: (i) length of infection, (ii) demographics, (iii) HIV-1 viral load (VL), (iv) change in CD4+ T-lymphocyte count (CD4 slope), (v) HIV-1 subtype, and (vi) host genetics, especially human leukocyte antigen (HLA) variants. Data from 499 HIV-1 seroconverters with frequent (monthly to quarterly) follow-up revealed that CD4:CD8 ratio was stable in the first 3 years of infection, with a modest correlation with VL and CD4 slope. A relatively normal CD4:CD8 ratio (>1.0) in early infection was associated with a substantial delay in disease progression to severe immunodeficiency (<350 CD4 cells/μl), regardless of other correlates of HIV-1 pathogenesis (adjusted hazards ratio (HR) = 0.43, 95% confidence interval (CI) = 0.29-0.63, P < 0.0001). Low VL (<10,000 copies/ml) and HLA-A*74:01 were the main predictors of CD4:CD8 ratio >1.0, but HLA variants (e.g., HLA-B*57 and HLA-B*81) previously associated with VL and/or CD4 trajectories in eastern and southern Africans had no obvious impact on CD4:CD8 ratio. Collectively, these findings suggest that CD4:CD8 ratio is a robust measure of immunologic health with both clinical and epidemiological implications.

Can HIV-1-Specific ADCC Assist the Clearance of Reactivated Latently Infected Cells?

Combination antiretroviral therapy (cART) has transformed the outcome of human immunodeficiency virus-1 (HIV-1) infection from a severe immunodeficiency syndrome to a chronic clinically manageable disease. However, patients require lifelong therapy and are at risk of developing non-AIDS complications (1, 2). Despite viral suppression in patients on cART, HIV-1 persists via the establishment of a latent reservoir. The adverse aspects and burden of lifelong cART together with the establishment of HIV-1 latency substantiate the need for an HIV-1 cure. A cure will either require complete eradication of the latent HIV-1 reservoir (termed “sterilizing cure”), or a sufficient reduction of HIV-1 levels wherein long-term viral suppression can be achieved without cART (termed “functional cure”). A key barrier to an HIV-1 cure is the persistence of latent replication-competent HIV-1 within long-lived resting CD4+ T cells (3). Without active HIV-1 replication or antigen expression, these latently infected cells are hidden from cART and are not eliminated by immune responses.

Prevalence of malnutrition among HIV-infected children in Central and West-African HIV-care programmes supported by the Growing Up Programme in 2011: a cross-sectional study.

BackgroundThe burden of malnutrition among HIV-infected children is not well described in sub-Saharan Africa, even though it is an important problem to take into account to guarantee appropriate healthcare for these children. We assessed the prevalence of malnutrition and its associated factors among HIV-infected children in HIV care programmes in Central and West-Africa.MethodsA cross-sectional study was conducted from September to December 2011 among the active files of HIV-infected children aged 2–19 years old, enrolled in HIV-care programmes supported by the Sidaction Growing Up Programme in Benin, Burundi, Cameroon, Côte d’Ivoire, Mali, Chad and Togo. Socio-demographics characteristics, anthropometric, clinical data, and nutritional support were collected. Anthropometric indicators, expressed in Z-scores, were used to define malnutrition: Height-for-age (HAZ), Weight-for-Height (WHZ) for children < 5 years and BMI-for-age (BAZ) for children ≥5 years. Three types of malnutrition were defined: acute malnutrition (WHZ/BAZ < -2 SD and HAZ ≥ -2 SD), chronic malnutrition (HAZ < -2 SD and WHZ/BAZ ≥ -2 SD) and mixed malnutrition (WHZ/BAZ < -2 SD and HAZ < -2 SD). A multinomial logistic regression model explored associated factors with each type of malnutrition.ResultsOverall, 1350 HIV-infected children were included; their median age was 10 years (interquartile range [IQR]: 7–13 years), 49 % were girls. 80 % were on antiretroviral treatment (ART), for a median time of 36 months. The prevalence of malnutrition was 42 % (95 % confidence interval [95% CI]: 40-44 %) with acute, chronic and mixed malnutrition at 9 % (95% CI: 6–12 %), 26 % (95% CI: 23–28 %), and 7 % (95% CI: 5–10 %), respectively. Among those malnourished, more than half of children didn’t receive any nutritional support at the time of the survey. Acute malnutrition was associated with male gender, severe immunodeficiency, and the absence of ART; chronic malnutrition with male gender and age (<5 years); and mixed malnutrition with male gender, age (<5 years), severe immunodeficiency and recent ART initiation (<6 months). Orphanhood and Cotrimoxazole prophylaxis were not associated with any type of malnutrition.ConclusionsThe prevalence of malnutrition in HIV-infected children even on ART remains high in HIV care programmes. Anthropometric measurements and appropriate nutritional care of malnourished HIV-infected children remain insufficient and a priority to improve health care of HIV-infected children in Africa.

Novel Genome-Editing Tools to Model and Correct Primary Immunodeficiencies.

Severe combined immunodeficiency (SCID) and other severe non-SCID primary immunodeficiencies (non-SCID PID) can be treated by allogeneic hematopoietic stem cell (HSC) transplantation, but when histocompatibility leukocyte antigen-matched donors are lacking, this can be a high-risk procedure. Correcting the patient’s own HSCs with gene therapy offers an attractive alternative. Gene therapies currently being used in clinical settings insert a functional copy of the entire gene by means of a viral vector. With this treatment, severe complications may result due to integration within oncogenes. A promising alternative is the use of endonucleases such as ZFNs, TALENs, and CRISPR/Cas9 to introduce a double-stranded break in the DNA and thus induce homology-directed repair. With these genome-editing tools a correct copy can be inserted in a precisely targeted “safe harbor.” They can also be used to correct pathogenic mutations in situ and to develop cellular or animal models needed to study the pathogenic effects of specific genetic defects found in immunodeficient patients. This review discusses the advantages and disadvantages of these endonucleases in gene correction and modeling with an emphasis on CRISPR/Cas9, which offers the most promise due to its efficacy and versatility.

Surface Plasmon Resonance Analysis Shows an IgG-Isotype-Specific Defect in ABO Blood Group Antibody Formation in Patients with Common Variable Immunodeficiency.

Common variable immunodeficiency (CVID) is the most common clinically severe primary immunodeficiency and comprises a heterogeneous group of patients with recurrent severe bacterial infections due to the failure to produce IgG antibodies after exposure to infectious agents and immunization. Diagnostic recommendations for antibody failure include assessment of isoagglutinins. We have readdressed this four decades old but still accepted recommendation with up to date methodology. Anti-A/B IgM- and IgG-antibodies were measured by Diamed-ID Micro Typing, surface plasmon resonance (SPR) using the Biacore(®) device and flow cytometry. When Diamed-ID Micro Typing was used, CVID patients (n = 34) showed IgG- and IgM-isoagglutinins that were comparable to healthy volunteers (n = 28), while all XLA patients (n = 8) had none. Anti-A/B IgM-antibodies were present in more than 2/3 of the CVID patients and showed binding kinetics comparable to anti-A/B IgM-antibodies from healthy individuals. A correlation could be found in CVID patients between levels of anti-A/B IgM-antibodies and levels of serum IgM and PnP-IgM-antibodies. In contrast in CVID patients as a group ABO antibodies were significantly decreased when assessed by SPR, which correlated with levels of switched memory, non-switched memory and naïve B cells, but all CVID patients had low/undetectable anti-A/B IgG-antibodies. These results indicate that conventional isoagglutinin assessment and assessment of anti-A/B IgM antibodies are not suited for the diagnosis of impaired antibody production in CVID. Examination of anti-A/B IgG antibodies by SPR provides a useful method for the diagnosis of IgG antibody failure in all CVID patients studied, thus indicating an important additional rationale to start immunoglobulin replacement therapy early in these patients, before post-infectious sequelae develop.

289. Safe and Effective Gene Therapy for Wiskott – Aldrich Syndrome Using an Insulated Lentiviral Vector

Wiskott–Aldrich Syndrome (WAS) is a severe X-linked immunodeficiency disorder characterized by recurrent infection, thrombocytopenia, and autoimmunity resulting from mutations within the WAS gene. The encoded gene product, WAS protein (WASp), is a scaffold protein important for activation of the actin cytoskeleton downstream of multiple hematopoietic receptors. Development of safe and effective hematopoietic stem cell (HSC) gene therapy for WAS would provide a valuable treatment alternative to allogeneic bone marrow transplantation. Of critical importance for such an approach is the capacity to achieve sufficient WASp expression in relevant lineages to correct the multiple deficits, while avoiding development of autoimmune disease. We previously tested a panel of self-inactivating (SIN) lentiviral (LV) vectors expressing human WAS via alternative internal promoters and observed optimal expression and rescue using the modified γ-retroviral derived LTR, MND. To improve the potential safety and stability of expression, we incorporated a 650bp chimeric insulator from the chicken β-globin locus into this LV. Using in vitro assays the insulated LV exhibited minimal LMO2 transactivation and no evidence for immortalization of cultured HSC. Next, we generated a stable high-titer producer clone expressing this candidate clinical LV, CL20-i650–MND-WAS. Here, we evaluate the efficacy and safety of the insulted vs uninsulated LV (CL20-MND-WAS) in a large cohort of primary and secondary transplanted Was/- mice. Both vectors enabled stable engraftment of WASp expressing cells in all hematopoietic lineages, positive selection of WASp+ cells, and rescued functional and developmental T and B cell defects without evidence for toxicity. Inclusion of the insulator allowed for higher expression levels at lower numbers of viral integration per cell; a feature that was further exaggerated in secondary recipients. Finally, in parallel, we evaluated CL20-i650–MND LV expressing a fluorescent marker using CD34+ autologous HSC transplants in a non-human primate model (Macaca nemestrina) and observed long term stable polyclonal engraftment of LV expressing hematopoietic cells for up to 2 yr. Based on these extensive pre-clinical and toxicity studies we anticipate that CL20-i650–MND-WAS LV will provide sustained rescue of platelet and lymphocyte development and function in vivo (facilitated, in part, via the insulator) without evidence of toxicity. We plan to directly test this hypothesis in an upcoming WAS LV clinical trial.

Differences in antigen-specific CD4+ responses to opportunistic infections in HIV infection.

HIV-infected individuals with severe immunodeficiency are at risk of opportunistic infection (OI). Tuberculosis (TB) may occur without substantial immune suppression suggesting an early and sustained adverse impact of HIV on Mycobacterium tuberculosis (MTB)-specific cell mediated immunity (CMI). This prospective observational cohort study aimed to observe differences in OI-specific and MTB-specific CMI that might underlie this. Using polychromatic flow cytometry, we compared CD4+ responses to MTB, cytomegalovirus (CMV), Epstein-Barr virus (EBV) and Candida albicans in individuals with and without HIV infection. MTB-specific CD4+ T-cells were more polyfunctional than virus specific (CMV/EBV) CD4+ T-cells which predominantly secreted IFN-gamma (IFN-γ) only. There was a reduced frequency of IFN-γ and IL-2 (IL-2)-dual-MTB-specific cells in HIV-infected individuals, which was not apparent for the other pathogens. MTB-specific cells were less differentiated especially compared with CMV-specific cells. CD127 expression was relatively less frequent on MTB-specific cells in HIV co-infection. MTB-specific CD4+ T-cells PD-1 expression was infrequent in contrast to EBV-specific CD4+ T-cells. The variation in the inherent quality of these CD4+ T-cell responses and impact of HIV co-infection may contribute to the timing of co-infectious diseases in HIV infection.

Missense mutation in immunodeficient patients shows the multifunctional roles of coiled-coil domain 3 (CC3) in STIM1 activation

Store-operated Ca(2+) entry (SOCE) is a universal Ca(2+) influx pathway that is important for the function of many cell types. SOCE occurs upon depletion of endoplasmic reticulum (ER) Ca(2+) stores and relies on a complex molecular interplay between the plasma membrane (PM) Ca(2+) channel ORAI1 and the ER Ca(2+) sensor stromal interaction molecule (STIM) 1. Patients with null mutations in ORAI1 or STIM1 genes present with severe combined immunodeficiency (SCID)-like disease. Here, we describe the molecular mechanisms by which a loss-of-function STIM1 mutation (R429C) in human patients abolishes SOCE. R429 is located in the third coiled-coil (CC3) domain of the cytoplasmic C terminus of STIM1. Mutation of R429 destabilizes the CC3 structure and alters the conformation of the STIM1 C terminus, thereby releasing a polybasic domain that promotes STIM1 recruitment to ER-PM junctions. However, the mutation also impairs cytoplasmic STIM1 oligomerization and abolishes STIM1-ORAI1 interactions. Thus, despite its constitutive localization at ER-PM junctions, mutant STIM1 fails to activate SOCE. Our results demonstrate multifunctional roles of the CC3 domain in regulating intra- and intermolecular STIM1 interactions that control (i) transition of STIM1 from a quiescent to an active conformational state, (ii) cytoplasmic STIM1 oligomerization, and (iii) STIM1-ORAI1 binding required for ORAI1 activation.

Role for Artemis nuclease in the repair of radiation-induced DNA double strand breaks by alternative end joining.

Exposure of cells to ionizing radiation or radiomimetic drugs generates DNA double-strand breaks that are processed either by homologous recombination repair (HRR), or by canonical, DNA-PKcs-dependent non-homologous end-joining (C-NHEJ). Chemical or genetic inactivation of factors involved in C-NHEJ or HRR, but also their local failure in repair proficient cells, promotes an alternative, error-prone end-joining pathway that serves as backup (A-EJ). There is evidence for the involvement of Artemis endonuclease, a protein deficient in a human radiosensitivity syndrome associated with severe immunodeficiency (RS-SCID), in the processing of subsets of DSBs by HRR or C-NHEJ. It is thought that within HRR or C-NHEJ Artemis processes DNA termini at complex DSBs. Whether Artemis has a role in A-EJ remains unknown. Here, we analyze using pulsed-field gel electrophoresis (PFGE) and specialized reporter assays, DSB repair in wild-type pre-B NALM-6 lymphocytes, as well as in their Artemis(-/-), DNA ligase 4(-/-) (LIG4(-/-)), and LIG4(-/-)/Artemis(-/-) double mutant counterparts, under conditions allowing evaluation of A-EJ. Our results substantiate the suggested roles of Artemis in C-NHEJ and HRR, but also demonstrate a role for the protein in A-EJ that is confirmed in Artemis deficient normal human fibroblasts. We conclude that Artemis is a nuclease participating in DSB repair by all major repair pathways.

Déficit complet en adénosine-désaminase-1 : une erreur innée du métabolisme responsable d’un déficit immunitaire combiné sévère

Severe combined immune deficiencies (SCIDs) are a heterogeneous group of severe cellular immunodeficiencies. Early diagnosis is essential to allow adapted care before life-threatening systemic infections or complications associated with live vaccines. Adenosine deaminase 1 deficiency (ADA1) is an inborn error of metabolism leading to severe lymphopenia and characteristic bone lesions. Herein, we present the typical case of a child in whom ADA SCID was diagnosed at 2 months of life, revealed by lung involvement and extreme lymphopenia. Immune restoration in terms of peripheral lymphocyte count with enzyme replacement therapy, namely pegylated bovine ADA, is satisfactory so far. The search for a compatible donor is underway. Correcting the genetic defect by gene transfer is also being considered. The phenotype of this very rare condition is described. A severe peripheral lymphopenia in a young child is a finding of utmost importance for the diagnosis of a primary cellular immunodeficiency.

Neonatal Levels of T-cell Receptor Excision Circles (TREC) in Patients with 22q11.2 Deletion Syndrome and Later Disease Features.

Newborns with severe T-cell lymphopenia, including those with 22q11.2 deletion syndrome (DS), have low numbers of T-cell receptor excision circles (TRECs). The aim of this study was to determine a possible correlation between neonatal TRECs in 22q11.2DS and the development of different phenotypes to elucidate the prognostic value of TREC in this disease. In this national survey including 46 patients with 22q11.2DS born after 2005, TREC levels were determined using stored newborn screening blood spots on filter cards. Patients were grouped into quartiles according to their TREC values, except the two infants with thymus aplasia. The two patients with thymic aplasia had no detectable TREC. The rest had no severe clinical immunodeficiency. There was a significant correlation between low TRECs and the proportion of patients with CD3(+)CD4(+)T-cells below the 5th percentile of healthy infants (p = 0.027) as well as the proportion with an abnormal thymus feature either no thymus or remnant thymus as observed during heart surgery (p = 0.022). Significantly lower TRECs (p = 0.019) were found in patients with cardiac defects compared to no such defects. Patients within the lowest quartile of TREC values (<71 TRECs/μL, n = 11) had more frequent severe cardiac defects than the other quartiles (p = 0.010). Eight of these patients in the lowest quartile needed an operation/intervention within two weeks after birth or died because of a cardiac defect. The low TREC values not only correlate with decreased T-cell immunity, but also with the occurrence of heart defects in the patients.

B-cell reconstitution after lentiviral vector–mediated gene therapy in patients with Wiskott-Aldrich syndrome

BackgroundWiskott-Aldrich syndrome (WAS) is a severe X-linked immunodeficiency characterized by microthrombocytopenia, eczema, recurrent infections, and susceptibility to autoimmunity and lymphomas. Hematopoietic stem cell transplantation is the treatment of choice; however, administration of WAS gene–corrected autologous hematopoietic stem cells has been demonstrated as a feasible alternative therapeutic approach.ObjectiveBecause B-cell homeostasis is perturbed in patients with WAS and restoration of immune competence is one of the main therapeutic goals, we have evaluated reconstitution of the B-cell compartment in 4 patients who received autologous hematopoietic stem cells transduced with lentiviral vector after a reduced-intensity conditioning regimen combined with anti-CD20 administration.MethodsWe evaluated B-cell counts, B-cell subset distribution, B cell–activating factor and immunoglobulin levels, and autoantibody production before and after gene therapy (GT). WAS gene transfer in B cells was assessed by measuring vector copy numbers and expression of Wiskott-Aldrich syndrome protein.ResultsAfter lentiviral vector-mediated GT, the number of transduced B cells progressively increased in the peripheral blood of all patients. Lentiviral vector-transduced progenitor cells were able to repopulate the B-cell compartment with a normal distribution of B-cell subsets both in bone marrow and the periphery, showing a WAS protein expression profile similar to that of healthy donors. In addition, after GT, we observed a normalized frequency of autoimmune-associated CD19+CD21−CD35− and CD21low B cells and a reduction in B cell–activating factor levels. Immunoglobulin serum levels and autoantibody production improved in all treated patients.ConclusionsWe provide evidence that lentiviral vector-mediated GT induces transgene expression in the B-cell compartment, resulting in ameliorated B-cell development and functionality and contributing to immunologic improvement in patients with WAS.

Coincidental loss of DOCK8 function in NLRP10-deficient and C3H/HeJ mice results in defective dendritic cell migration

Dendritic cells (DCs) are the primary leukocytes responsible for priming T cells. To find and activate naïve T cells, DCs must migrate to lymph nodes, yet the cellular programs responsible for this key step remain unclear. DC migration to lymph nodes and the subsequent T-cell response are disrupted in a mouse we recently described lacking the NOD-like receptor NLRP10 (NLR family, pyrin domain containing 10); however, the mechanism by which this pattern recognition receptor governs DC migration remained unknown. Using a proteomic approach, we discovered that DCs from Nlrp10 knockout mice lack the guanine nucleotide exchange factor DOCK8 (dedicator of cytokinesis 8), which regulates cytoskeleton dynamics in multiple leukocyte populations; in humans, loss-of-function mutations in Dock8 result in severe immunodeficiency. Surprisingly, Nlrp10 knockout mice crossed to other backgrounds had normal DOCK8 expression. This suggested that the original Nlrp10 knockout strain harbored an unexpected mutation in Dock8, which was confirmed using whole-exome sequencing. Consistent with our original report, NLRP3 inflammasome activation remained unaltered in NLRP10-deficient DCs even after restoring DOCK8 function; however, these DCs recovered the ability to migrate. Isolated loss of DOCK8 via targeted deletion confirmed its absolute requirement for DC migration. Because mutations in Dock genes have been discovered in other mouse lines, we analyzed the diversity of Dock8 across different murine strains and found that C3H/HeJ mice also harbor a Dock8 mutation that partially impairs DC migration. We conclude that DOCK8 is an important regulator of DC migration during an immune response and is prone to mutations that disrupt its crucial function.

Detection of impaired IgG antibody formation facilitates the decision on early immunoglobulin replacement in hypogammaglobulinemic patients.

Hypogammaglobulinemia (serum IgG lower than 2 SD below the age-matched mean) and clinical symptoms such as increased susceptibility to infection, autoimmune manifestations, granulomatous disease, and unexplained polyclonal lymphoproliferation are considered to be diagnostic hallmarks in patients with common variable immunodeficiency (CVID), the most frequent clinically severe primary immunodeficiency syndrome. In the present study, we investigated patients with hypogammaglobulinemia and no clinical or immunological signs of defective cell-mediated immunity and differentiated two groups on the basis of their IgG antibody formation capacity against a variety of different antigens (bacterial toxins, polysaccharide antigens, viral antigens). Patients with hypogammaglobulinemia and intact antibody production (HIAP) displayed no or only mild susceptibility to infections, while CVID patients showed marked susceptibility to bacterial infections that normalized following initiation of IVIG or subcutaneous immunoglobulin replacement therapy. There was a substantial overlap in IgG serum levels between the asymptomatic HIAP group and the CVID patients examined before immunoglobulin treatment. HIAP patients showed normal levels of switched B-memory cells (CD19+CD27+IgD−), while both decreased and normal levels of switched B-memory cells could be found in CVID patients. IgG antibody response to a primary antigen, tick-borne encephalitis virus (TBEV), was defective in CVID patients, thus confirming their substantial defect in IgG antibody production. Defective IgG antibody production against multiple antigens could also be demonstrated in an adult patient with recurrent infections but normal IgG levels. To facilitate early treatment before recurrent infections may lead to organ damage, the antibody formation capacity should be examined in hypogammaglobulinemic patients and the decision to treat should be based on the finding of impaired IgG antibody production.

Variable phenotype of severe immunodeficiencies associated with RMRP gene mutations.

Mutations in RMRP primarily give rise to Cartilage Hair Hypoplasia (CHH), a highly diverse skeletal disorder which can be associated with severe immunodeficiency. Increased availability of RMRP mutation screening has uncovered a number of infants with significant immunodeficiency but only mild or absent skeletal features. We surveyed the clinical and immunological phenotype of children who have undergone allogeneic haematopoietic stem cell transplantation for this condition in the UK. Thirteen patients with confirmed RMRP mutations underwent allogeneic stem cell transplantation (SCT) at two nationally commissioned centres using a variety of donors and conditioning regimens. Records were retrospectively reviewed. Median time from clinical presentation to diagnosis was 12 months (range 1 to 276 months), with three infants diagnosed with severe combined immunodeficiency (SCID) without radiographical manifestations of CHH. A total of 17 allogeneic procedures were performed on 13 patients including two stem-cell top-ups. The median age at transplant was 32.4 months (range 1.5 to 125 months). Of the eleven surviving patients, median follow-up was 50 months (range 21.6 to 168 months). RMRP mutations can cause short stature and significant immunodeficiency which can be corrected by allogeneic SCT and the diagnosis should be considered even in the absence of skeletal manifestations.

Immunodeficiency and Immunomonitoring

Abstract Immunological diagnostics is a rapidly developing area in laboratory medicine. Most recently, major developments in the area of immunodeficiency and the monitoring of chronic inflammatory diseases have been observed. Regarding immuno-monitoring, recently a consensus panel for basic flow cytometry has been published together with age-related reference values. In the USA, the search for severe inherited immunodeficiency diseases (such as severe combined immunodeficiency disease, SCID) is part of neonatal screening procedures. Recently, several US states published first results which are based on the measurement of T-cell receptor excision circles (TRECs). Furthermore, age-dependent reference values for the measurement of IgG subclasses and subclass-specific vaccination antibodies have been published. Monitoring of chronic inflammatory disease focuses on asthma. A novel classification based on the cellular distribution of neutrophils versus eosinophils in induced sputum has been developed. Furthermore, novel biomarkers, such as periostin, are currently under evaluation. Such novel approaches of phenotyping are now the basis of individualized therapeutic approaches in patients with (severe) asthma, who respond to certain biologicals.

Lack of antiviral antibody response in koalas infected with koala retroviruses (KoRV)

Many wild koalas are infected with the koala retrovirus, KoRV, some of which suffer from lymphoma and chlamydial disease. Three subgroups, KoRV-A, KoRV-B and KoRV-J, have so far been described. It is well known that other closely related gammaretroviruses can induce tumours and severe immunodeficiencies in their respective hosts and a possible role for KoRV infection in lymphoma and chlamydial disease in koalas has been suggested. In many wild koalas, KoRV-A has become endogenised, i.e., it is integrated in the germ-line and is passed on with normal cellular genes. In this study, sera from koalas in European zoos and from wild animals in Australia were screened for antibodies against KoRV-A. These naturally infected animals all carry endogenous KoRV-A and two zoo animals are also infected with KoRV-B. The antibody response is generally an important diagnostic tool for detecting retrovirus infections. However, when Western blot analyses were performed using purified virus or recombinant proteins corresponding to KoRV-A, none of the koalas tested positive for specific antibodies, suggesting a state of tolerance. These results have implications for koala vaccination, as they suggest that therapeutic immunisation of animals carrying and expressing endogenous KoRV-A will not be successful. However, it remains unclear whether these animals can be immunised against KoRV-B and immunisation of uninfected koalas could still be worthwhile.

Immunodeficiency in children starting antiretroviral therapy in low-, middle-, and high-income countries.

The CD4 cell count or percent (CD4%) at the start of combination antiretroviral therapy (cART) is an important prognostic factor in children starting therapy and an important indicator of program performance. We describe trends and determinants of CD4 measures at cART initiation in children from low-, middle-, and high-income countries. We included children aged <16 years from clinics participating in a collaborative study spanning sub-Saharan Africa, Asia, Latin America, and the United States. Missing CD4 values at cART start were estimated through multiple imputation. Severe immunodeficiency was defined according to World Health Organization criteria. Analyses used generalized additive mixed models adjusted for age, country, and calendar year. A total of 34,706 children from 9 low-income, 6 lower middle-income, 4 upper middle-income countries, and 1 high-income country (United States) were included; 20,624 children (59%) had severe immunodeficiency. In low-income countries, the estimated prevalence of children starting cART with severe immunodeficiency declined from 76% in 2004 to 63% in 2010. Corresponding figures for lower middle-income countries were from 77% to 66% and for upper middle-income countries from 75% to 58%. In the United States, the percentage decreased from 42% to 19% during the period 1996 to 2006. In low- and middle-income countries, infants and children aged 12-15 years had the highest prevalence of severe immunodeficiency at cART initiation. Despite progress in most low- and middle-income countries, many children continue to start cART with severe immunodeficiency. Early diagnosis and treatment of HIV-infected children to prevent morbidity and mortality associated with immunodeficiency must remain a global public health priority.

Serum ferritin levels in human immunodeficiency virus infected children and its relation with severe immunodeficiency

Background: Ferritin is an acute phase protein which is often elevated in acute and chronic inflammation. In adults with human immunodeficiency virus (HIV) infection, elevated serum ferritin levels indicate advanced or progressive disease. In the present study, ferritin levels were evaluated in HIV infected children to find out its relation with the immune deficiency. Methods: The children who were HIV positive (confirmed by ELISA for HIV-1 and HIV-2), and attending the OPD of ART Centre and of tertiary care center during period of one year were included in the study. The study population consisted of 47 patients, belonging to both sexes and age of 18 months to 19 years. Detailed history was taken and full clinical examination done in all cases. Blood sample for Complete blood count, serum ferritin and CD4 count was taken. Absolute CD4 count of each patient was obtained and immunological staging was done on the basis of WHO immunological staging criteria. Serum ferritin level 7-140 ngm/mL was considered normal. Results: Hyperferritenimia (&gt;140 ngm/ mL) is a feature of advanced stages of HIV infection. 11.1% patients of stage 3 and 40.0% patients of stage 4 are showing hyperferritinemia (r = 0.890), irrespective of anemia. Low serum ferritin level (&lt;7 ngm/mL) is an unusual feature in HIV infected children. Conclusions: High Serum ferritin levels are not uncommon in children with HIV disease and they are related with immunological progression of the disease.

Antibody response to VZV vaccination in HIV infected children

AimTo evaluate the effectiveness of varicella vaccination based on the presence of VZV antibodies in HIV-infected children and to establish factors influencing vaccination response. BackgroundVZV vaccination is recommended in HIV-infected children without severe immunodeficiency. This group of children may not produce sufficient immunologic response. Materials and methodsPost vaccination antibodies were evaluated in 21 HIV-infected children who received 2 doses of varicella vaccine. VZV antibodies were checked after the second vaccine dose using VIDAS Varicella-Zoster IgG ELFA technique. All patients have been receiving combined antiretroviral treatment (cART). The analyzed factors included: age at HIV diagnosis, age when receiving the first vaccine dose, Centers for Disease Control and Prevention (CDC) classification at diagnosis, at time of vaccination and at evaluation. ResultsPost-vaccination VZV antibodies were present in 52% of patients. HIV infection was diagnosed at the mean age of 13 months (range 1 month to 4.5 years). Prior to evaluation 11/21 children had experienced moderate to severe HIV symptoms. Six children experienced severe immunodeficiency, 6 were moderate immunodeficient in the past, 46% of them responded to vaccination. At time of vaccination all the children were immunocompetent. At the time of the antibodies evaluation 20 children were classified N1/A1, one received C1 classification due to HIV encephalopathy. The subjects who had VZV protective antibody titers had shorter time since vaccination and were less likely to have prior immunodeficiency. No children developed varicella during the mean 3.5 years of follow-up. ConclusionSerological immune response to varicella vaccination in HIV-infected children was insufficient.