Severe Immunodeficiency Research Articles

Fetal MRI of hereditary multiple intestinal atresia with postnatal correlation

Hereditary multiple intestinal atresia (HMIA) is an extremely uncommon cause of congenital bowel obstruction. The morbidity and mortality of this disease differ significantly from those of isolated intestinal atresias and non-hereditary forms of multiple intestinal atresia. Most notably, despite successful operative repairs of the atresias found in this disease, HMIA maintains a 100% lethality rate from continued post-operative intestinal failure and an associated severe immunodeficiency. We present a case of HMIA evaluated with fetal MRI and subsequently diagnosed by a combination of corroborative postnatal imaging with surgical exploration and pathological examination.

Successful cure of C1q deficiency in human subjects treated with hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) is used to cure a number of primary immunodeficiency diseases but has never been attempted for patients with complement deficiencies because most complement factors are produced in the liver rather than the bone marrow. Inherited deficiency of the C1q component of the classical complement pathway is a severe autosomal recessive immunodeficiency disease associated with a high risk of death from either fulminant bacterial infections or systemic lupus erythematosus–like autoimmunity.

Brief report: A human induced pluripotent stem cell model of cernunnos deficiency reveals an important role for XLF in the survival of the primitive hematopoietic progenitors

Cernunnos (also known as XLF) deficiency syndrome is a rare recessive autosomal disorder caused by mutations in the XLF gene, a key factor involved in the end joining step of DNA during nonhomologous end joining (NHEJ) process. Human patients with XLF mutations display microcephaly, developmental and growth delays, and severe immunodeficiency. While the clinical phenotype of DNA damage disorders, including XLF Syndrome, has been described extensively, the underlying mechanisms of disease onset, are as yet, undefined. We have been able to generate an induced pluripotent stem cell (iPSC) model of XLF deficiency, which accurately replicates the double-strand break repair deficiency observed in XLF patients. XLF patient-specific iPSCs (XLF-iPSC) show typical expression of pluripotency markers, but have altered in vitro differentiation capacity and an inability to generate teratomas comprised of all three germ layers in vivo. Our results demonstrate that XLF-iPSCs possess a weak NHEJ-mediated DNA repair capacity that is incapable of coping with the DNA lesions introduced by physiological stress, normal metabolism, and ionizing radiation. XLF-iPSC lines are capable of hematopoietic differentiation; however, the more primitive subsets of hematopoietic progenitors display increased apoptosis in culture and an inability to repair DNA damage. Together, our findings highlight the importance of NHEJ-mediated-DNA repair in the maintenance of a pristine pool of hematopoietic progenitors during human embryonic development.

Candida albicans osteomyelitis in an infant

Skeletal infections secondary to Candida albicans are uncommon and described primarily in adults. Nearly all 22 pediatric cases of C. albicans osteomyelitis described to date have occurred in neonates with specific risk factors or in children with a severe immunodeficiency. We report an unusual presentation of C. albicans osteomyelitis and arthritis in a 1-year-old boy without an immunodeficiency, which led to a delayed diagnosis. He most likely developed C. albicans arthritis and osteomyelitis during the neonatal period with a subsequent indolent and subacute presentation. Our literature search found no prior or recent reviews of C. albicans osteomyelitis in pediatric patients. On the basis of this patient and the case reports previously published, we discuss an approach to the evaluation and management of pediatric patients with Candida osteomyelitis.

Anti‐tumour activity and store operated calcium entry: new roles in immunology

Ca2+ signalling plays a critical role in almost every cell type of the immune system—T cells, B cells, NK cells, macrophages and mast cells. Intracellular Ca2+ signals in immunology have importance in both the short term and long term function of these cells. Short term functions like release of cytotoxic granules with inflammatory mediators, immune synapse formations and long term functions like cell differentiation, expression and proliferation are all regulated to various degrees by intracellular Ca2+ signals. Store operated calcium entry (SOCE) is one of the critical modulators of the Ca2+ signals that control these processes. The importance of SOCE in normal immune physiology has already been demonstrated in families with mutations in STIM1, STIM2 and Orai1 who demonstrate a severe immunodeficiency that causes bacterial, viral and fungal infections (Picard et al, 2009). Alterations in the immune system due to changes in Ca2+ homeostasis has spiked interest in studying the role of SOCE in another critical function of the immune system—anticancer immunity. Relatively little is known about SOCE and its role in oncology and the evidence gathered so far seems to suggest that it is both important in tumour detection as well as tumour growth (Prevarskaya et al, 2011). Mouse models have shown that STIM1 and Orai1 expression is critical for breast cell tumour migration and metastasis (Yang et al, 2009). Other work in human prostate cancer cells has shown that normal expression of Orai1 and SOCE are critical in maintaining the rate of apoptosis and thus, resistance to prostate cancer (Flourakis et al, 2010). Given the conflicting nature of the research in the role of SOCE in cancer immunity, it is necessary to appreciate that Ca2+ regulates a variety of complex immune functions, not all of which are cancer protective. More importantly, delineating …

A Recessive Founder Mutation in Regulator of Telomere Elongation Helicase 1, RTEL1, Underlies Severe Immunodeficiency and Features of Hoyeraal Hreidarsson Syndrome

Dyskeratosis congenita (DC) is a heterogeneous inherited bone marrow failure and cancer predisposition syndrome in which germline mutations in telomere biology genes account for approximately one-half of known families. Hoyeraal Hreidarsson syndrome (HH) is a clinically severe variant of DC in which patients also have cerebellar hypoplasia and may present with severe immunodeficiency and enteropathy. We discovered a germline autosomal recessive mutation in RTEL1, a helicase with critical telomeric functions, in two unrelated families of Ashkenazi Jewish (AJ) ancestry. The affected individuals in these families are homozygous for the same mutation, R1264H, which affects three isoforms of RTEL1. Each parent was a heterozygous carrier of one mutant allele. Patient-derived cell lines revealed evidence of telomere dysfunction, including significantly decreased telomere length, telomere length heterogeneity, and the presence of extra-chromosomal circular telomeric DNA. In addition, RTEL1 mutant cells exhibited enhanced sensitivity to the interstrand cross-linking agent mitomycin C. The molecular data and the patterns of inheritance are consistent with a hypomorphic mutation in RTEL1 as the underlying basis of the clinical and cellular phenotypes. This study further implicates RTEL1 in the etiology of DC/HH and immunodeficiency, and identifies the first known homozygous autosomal recessive disease-associated mutation in RTEL1.

Myelosuppression grading of chemotherapies for hematologic malignancies to facilitate communication between medical and dental staff: lessons from two cases experienced odontogenic septicemia

BackgroundOdontogenic diseases can be a risk factor for life-threatening infection in patients with hematologic malignancies during chemotherapy that induces myelosuppression of variable severity. Previous studies noted the necessity of the elimination of all odontogenic foci before hematopoietic stem cell transplantation. To enable planning for the adequate dental intervention, the oral medicine team must understand the general status of patient and the intensity of the chemotherapy, which is sometimes difficult to be fully appreciated by dental staff. Therefore, a simplified grading would facilitate the sharing of information between hematologists, dentists and oral hygienists. This study aimed to introduce our myelosuppression grading of chemotherapies for hematologic malignancies and analyze the timing of occurrence of severe odontogenic infection.Methods37 patients having received various chemotherapies for hematologic malignancies were enrolled. The chemotherapy regimens were classified into four grades based on the persistency of myelosuppression induced by chemotherapy. Mild myelosuppressive chemotherapies were classified as grade A, moderate ones as grade B, severe ones as grade C, and chemotherapies that caused severe myelosuppression and persistent immunodeficiency (known as conditioning regimens for transplant) as grade D. The timing of occurrence of severe odontogenic infection was retrospectively investigated.ResultsTwo patients (5.4%) had severe odontogenic infections after grade B or C chemotherapy. One occurred after extraction of non-salvageable teeth; the other resulted from advanced periodontitis in a tooth that could not be extracted because of thrombocytopenia. Both were de novo hematologic malignancy patients. During grade D chemotherapy, no patients had severe odontogenic infections.ConclusionsThe simplified grading introduced in this study is considered a useful tool for understanding the myelosuppressive state caused by chemotherapy and facilitating communication between medical and dental staff. During the period around the primary chemotherapy, especially for de novo hematologic malignancy patients who often received grade B to C myelosuppression chemotherapy, caution should be exercised for severe odontogenic infection by the oral medicine team, irrespective of whether invasive treatment is to be performed.

Irgm1 (LRG-47), a Regulator of Cell-Autonomous Immunity, Does Not Localize to Mycobacterial or Listerial Phagosomes in IFN-γ–Induced Mouse Cells

The IFN-inducible protein Irgm1 (LRG-47) belongs to the family of immunity-related GTPases that function in cell-autonomous resistance against intracellular pathogens in mice. Irgm1 deficiency is associated with a severe immunodeficiency syndrome. The protein has been variously interpreted as a direct effector molecule on bacterial phagosomes or on other organelles or as an inducer of autophagy. In this study, we re-examined one of these claims, namely that Irgm1 targets mycobacterial and listerial phagosomes. We found no colocalization of endogenous Irgm1, using two immunofluorescent staining techniques, either in fibroblasts or in macrophages. We demonstrated the predicted existence of two protein isoforms of Irgm1 derived from differential splicing and described immunological reagents for their detection. Both Irgm1 isoforms localize to the Golgi apparatus and weakly to mitochondria; however, only the long Irgm1 isoforms can be detected on endolysosomal membranes. Together with the previous observation that the general immunodeficiency phenotype of Irgm1(-/-) mice is reversed in Irgm1/Irgm3 double-deficient mice, our results argue against a direct effector function of Irgm1 at the bacterial phagosome. We discuss these findings in the context of evidence that Irgm1 functions as a negative regulator of other members of the immunity-related GTPase protein family.

Expression and characterization of highly antigenic domains of chicken anemia virus viral VP2 and VP3 subunit proteins in a recombinant E. colifor sero-diagnostic applications

BackgroundChicken anemia virus (CAV) is an important viral pathogen that causes anemia and severe immunodeficiency syndrome in chickens worldwide. Generally, CAV infection occurs via vertical transmission in young chicks that are less than two weeks old, which are very susceptible to the disease. Therefore, epidemiological investigations of CAV infection and/or the evaluation of the immunization status of chickens is necessary for disease control. Up to the present, systematically assessing viral protein antigenicity and/or determining the immunorelevant domain(s) of viral proteins during serological testing for CAV infection has never been performed. The expression, production and antigenic characterization of CAV viral proteins such as VP1, VP2 and VP3, and their use in the development of diagnostic kit would be useful for CAV infection prevention.ResultsThree CAV viral proteins VP1, VP2 and VP3 was separately cloned and expressed in recombinant E. coli. The purified recombinant CAV VP1, VP2 and VP3 proteins were then used as antigens in order to evaluate their reactivity against chicken sera using indirect ELISA. The results indicated that VP2 and VP3 show good immunoreactivity with CAV-positive chicken sera, whereas VP1 was found to show less immunoreactivity than VP2 and VP3. To carry out the further antigenic characterization of the immunorelevant domains of the VP2 and VP3 proteins, five recombinant VP2 subunit proteins (VP2-435N, VP2-396N, VP2-345N, VP2-171C and VP2-318C) and three recombinant VP3 subunit proteins (VP3-123N, VP3-246M, VP3-366C), spanning the defined regions of VP2 and VP3 were separately produced by an E. coli expression system. These peptides were then used as antigens in indirect ELISAs against chicken sera. The results of these ELISAs using truncated recombinant VP2 and VP3 subunit proteins as coating antigen showed that VP2-345N, VP2-396N and VP3-246M gave good immunoreactivity with CAV-positive chicken sera compared to the other subunit proteins. Moreover, the VP2-396N and VP2-345 based ELISAs had better sensitivity (97.5%) and excellent specificity (100%) during serodiagnosis testing using a mean plus three standard deviations cut-off. The VP3-246M based ELISA showed a sensitivity of 85% and a specificity of 100% at the same cut-off value.ConclusionsThis is the first report to systematically assess the antigenic characteristics of CAV viral proteins for sero-diagnosis purposes. Purified recombinant VP2-396N and VP2-345N subunit proteins, which span defined regions of VP2, were demonstrated to have good antigenicity and higher sensitivities than VP3-246M and were able to recognize CAV-positive chicken serum using an ELISA assay. The defined antigenicity potential of these chimeric subunit proteins produced by expression in E. coli seem to have potential and could be useful in the future for the development of the CAV diagnostic tests based on a subunit protein ELISA system.

The Transmembrane Protein of the Human Endogenous Retrovirus - K (HERV-K) Modulates Cytokine Release and Gene Expression

Numerous copies of endogenous retroviruses are present in the genome of mammals including man. Although most of them are defective, some, e.g., the human endogenous retroviruses HERV-K, were found to be expressed under certain physiological conditions. For instance, HERV-K is expressed in germ cell tumours and melanomas as well as in the placenta. Most exogenous retroviruses including the human immunodeficiency virus HIV-1 induce severe immunodeficiencies and there is increasing evidence that the transmembrane envelope (TM) proteins of these retroviruses may be involved. We show here that HERV-K particles released from a human teratocarcinoma cell line, a recombinant TM protein and a peptide corresponding to a highly conserved so-called immunosuppressive domain in the TM protein of HERV-K inhibit the proliferation of human immune cells, induce modulation of the expression of numerous cytokines, and modulate the expression of cellular genes as detected by a microarray analysis. The changes in cytokine release and gene expression induced by the TM protein of HERV-K are similar to those found previously induced by the TM protein of HIV-1. These data suggest that the mechanism of immunosuppression may be similar for different retroviruses and that the expression of the TM protein in tumours and in the placenta may suppress immune responses and thus prevent rejection of the tumour and the embryo.

High Retention Among HIV-infected Children in Rwanda During Scale-up and Decentralization of HIV Care and Treatment Programs, 2004 to 2010

Efforts to scale-up HIV treatment in high burden countries have resulted in wider access to care, improved survival and decreased morbidity for HIV-infected children. The country of Rwanda has made significant achievements in expanding coverage of pediatric HIV services. We describe the extent of and factors associated with mortality and lost to follow-up (LTF) in children (<15 years) enrolled in HIV care at 39 ICAP-supported facilities across Rwanda from 2004 to 2010 by antiretroviral treatment (ART) status. We estimated the 1-year cumulative incidence of death and LTF among all children enrolled in care (pre-ART) and children on ART. Survival analysis was used to evaluate factors associated with death and LTF in both groups. Between January 2004 and June 2010, 3244 children with a median age of 5.7 years (interquartile range 2.8-9.6) enrolled in HIV care. One-year cumulative incidence for death and LTF among pre-ART children was 4% (95% confidence interval [CI]: 3-5%) and 5% (95% CI: 4-6%), respectively. Overall, 2035 (63%) children initiated ART, median age 6.3 years (interquartile range 3.3-10.4): 1-year Kaplan-Meier estimates of death and LTF were 3% (95% CI: 3-4%) and 1% (95% CI: 1-2%), respectively. Factors associated with an increased hazard for death among pre-ART children included being <18 months old versus ≥5 years (adjusted sub hazard ratio [aSHR] = 4.4, 95% CI: 2.9-6.8) and World Health Organization stage IV versus I (aSHR = 4.1, 95% CI: 2.0-8.4), whereas children entering care through prevention of mother-to-child transmission had lower hazard than those from voluntary counseling and testing (aSHR = 0.50, 95% CI: 0.25-1.0). Markers of advanced disease, including severe immunosuppression (aSHR = 0.25, 95% CI: 0.12-0.54), and enrollment in care in rural versus urban clinics (aSHR = 0.71, 95% CI: 0.53-0.97) were protective against LTF. For children on ART, factors associated with hazard of death included younger age (adjusted hazard ratio [aHR] <18 months versus ≥5 years = 2.1, 95% CI: 1.3-3.6), severe malnutrition versus not malnourished (aHR = 3.2, 95% CI: 1.3-8.1), advanced World Health Organization stage (aHR IV versus I = 9.8, 95% CI: 3.5-27.4) and severe immunodeficiency versus no evidence (aHR = 2.3, 95% CI: 1.7-3.3). No associations were observed with LTF among children on ART. The results demonstrate very high retention among children enrolled in HIV care in Rwanda. Younger children continue to be particularly vulnerable, underscoring the urgent need for early identification, rapid treatment initiation and long-term retention in care.

T-cell reconstitution during murine acquired immunodeficiency syndrome (MAIDS) produces neuroinflammation and mortality in animals harboring opportunistic viral brain infection

BackgroundHighly active antiretroviral therapy (HAART) restores inflammatory immune responses in AIDS patients which may unmask previous subclinical infections or paradoxically exacerbate symptoms of opportunistic infections. In resource-poor settings, 25% of patients receiving HAART may develop CNS-related immune reconstitution inflammatory syndrome (IRIS). Here we describe a reliable mouse model to study underlying immunopathological mechanisms of CNS-IRIS.MethodsUtilizing our HSV brain infection model and mice with MAIDS, we investigated the effect of immune reconstitution on MAIDS mice harboring opportunistic viral brain infection. Using multi-color flow cytometry, we quantitatively measured the cellular infiltrate and microglial activation.ResultsInfection with the LP-BM5 retroviral mixture was found to confer susceptibility to herpes simplex virus (HSV)-1 brain infection to normally-resistant C57BL/6 mice. Increased susceptibility to brain infection was due to severe immunodeficiency at 8 wks p.i. and a marked increase in programmed death-1 (PD-1) expression on CD4+ and CD8+ T-cells. Both T-cell loss and opportunistic brain infection were associated with high level PD-1 expression because PD-1-knockout mice infected with LP-BM5 did not exhibit lymphopenia and retained resistance to HSV-1. In addition, HSV-infection of MAIDS mice stimulated peripheral immune cell infiltration into the brain and its ensuing microglial activation. Interestingly, while opportunistic herpes virus brain infection of C57BL/6 MAIDS mice was not itself lethal, when T-cell immunity was reconstituted through adoptive transfer of virus-specific CD3+ T-cells, it resulted in significant mortality among recipients. This immune reconstitution-induced mortality was associated with exacerbated neuroinflammation, as determined by MHC class II expression on resident microglia and elevated levels of Th1 cytokines in the brain.ConclusionsTaken together, these results indicate development of an immune reconstitution disease within the central nervous system (CNS-IRD). Experimental immune reconstitution disease of the CNS using T-cell repopulation of lymphopenic murine hosts harboring opportunistic brain infections may help elucidate neuroimmunoregulatory networks that produce CNS-IRIS in patients initiating HAART.

Individualization of antibacterial therapy in severe community acquired pneumonia considering systemic inflammation and immune status

Individualization of antibiotic therapy (ABT) of patients with severe community-acquired pneumonia (CAP) is a key issue in the world. Today the role of various biomarkers in ABT individualization in patients with CAP, including markers of systemic inflammation and cellular immunity is vividly discussed. But their variability at different etiological factors of CAP according to the immunological reactivity of patients was not studied at all. That’s why the aim of our study was to evaluate the diagnostic value of marker of systemic inflammation procalcitonin (PCT) and marker of cellular immunity CD4+ in patients with severe CAP, considering etiological factor and their role in individualization of antibiotic preparation (ABP) choice in these patients. A study group consisted of patients with severe CAP without HIV and identified respiratory pathogen. Comparison group consisted of HIV-positive persons, who accounted nearly 17% of all the patients. According to the results of this work it was revealed that in all patients CAP was accompanied with marked inflammatory response (which is confirmed by 250 times higher than normal serum PCT (level) and severe immunodeficiency state, even in HIV absence. The markers changed depending on CAP etiology. In CAP caused by Gr(-) pathogens PCT levels was 500 times higher than normal, and the number of CD4+ was less than normal in all patients. Conclusions: 1) reduced number of CD4, less than 200 ml -1 in patients with severe CAP, accompanied by a sharp increase in serum PCT level is a marker of Gr(-) respiratory pathogen; 2) the imbalance between clinical symptoms and normal serum PCT level against a sharp decline in CD4+number is an indication to search for HIV and administration of the antipneumocystic therapy.

Epstein Barr virus DNA analysis in blood predicts disease progression in a rare case of plasmablastic lymphoma with effusion

BackgroundIn HIV-1-infected patients a long lasting CD4+ cell decline influences the host-EBV balance and thereby increases the risk for EBV related malignancies. In spite of a world-wide access to combination antiretroviral therapy (cART) there are still a considerable number of HIV-1-infected patients who will develop severe immunodeficiency. These undiagnosed HIV-1 infected patients, so called late testers, demonstrate an increased lymphoma risk, compared to patients diagnosed early. Consecutive individual screening for EBV DNA-load in late testers might be a useful predictor of emerging EBV-malignancy.MethodsPatient biopsies and ascites were analyzed morphologically, by immuncyto-histochemistry and in-situ hybridization. Viral DNA and RNA load were quantified by PCR. Cell lines from primary tumor and from ascites, were established in vitro and further analyzed.ResultWe here report on a case of EBV-positive lymphoma in an AIDS patient, first presenting with pleural effusion and ascites and was thus initially considered a primary effusion lymphoma (PEL) but was later diagnosed as a plasmablastic lymphoma (PBL). The patient had responded to cART with undetectable HIV-RNA and increased CD4 cell count one year prior to lymphoma presentation. At the time of lymphoma diagnosis the HIV-RNA values were <50 RNA-copies per mL blood (undetectable) and the CD4-positive cell count 170 ×106/L. The lymphoma was CD45-negative and weakly CD22- and CD30-positive. The patient had a history of Kaposi sarcoma and HHV-8 seropositivity. The lymphoma biopsies, and three cell lines derived on different occasions from the tumor cell effusion, were all EBV-positive but HHV-8 negative.A noticeable EBV-DNA load decline was observed during the remission of the lymphoma following CHOP-therapy. The EBV-DNA load increased dramatically at the time of recurrence.ConclusionEBV DNA load might be useful in monitoring the effect of lymphoma treatment as well as in estimating the risk of EBV-associated lymphoma in HIV-1 infected patients with pronounced immunosuppression.

Inhibitors of BTK and ITK: State of the New Drugs for Cancer, Autoimmunity and Inflammatory Diseases

BTK and ITK are cytoplasmic tyrosine kinases of crucial importance for B and T cell development, with loss-of-function mutations causing X-linked agammaglobulinemia and susceptibility to severe, frequently lethal, Epstein-Barr virus infection, respectively. Over the last few years, considerable efforts have been made in order to develop small-molecule inhibitors for these kinases to treat lymphocyte malignancies, autoimmunity or allergy/hypersensitivity. The rationale is that even if complete lack of BTK or ITK during development causes severe immunodeficiency, inactivation after birth may result in a less severe phenotype. Moreover, therapy can be transient or only partially block the activity of BTK or ITK. Furthermore, a drug-induced B cell deficiency is treatable by gamma globulin substitution therapy. The newly developed BTK inhibitor PCI-32765, recently renamed Ibrutinib, has already entered several clinical trials for various forms of non-Hodgkin lymphoma as well as for multiple myeloma. Experimental animal studies have demonstrated highly promising treatment effects also in autoimmunity. ITK inhibitors are still under the early developmental phase, but it can be expected that such drugs will also become very useful. In this study, we present BTK and ITK with their signalling pathways and review the development of the corresponding inhibitors.

P2.181 IL-4, IL-10 and TNF-A Profile in North-Eastern Ukrainian HIV-1 Infected Individuals with Different Level of Immunodeficiency

BackgroundAim of the study was to determine the IL-4, IL-10 and TNF-α profiles in plasma of north-eastern Ukrainian HIV-1 infected individuals with different CD4 T-cell levels.MethodsWe used a immunoassay method...

Inmunodeficiencias congénitas del receptor de antígeno de los linfocitos T

T-cell receptor (TCR) immunodeficiencies of humans are low-prevalence autosomal recessive diseases characterized by impaired surface TCR expression and selective T lymphopenia (milder in CD3γ, TCRα or CD247 deficiency, and severe in individuals lacking CD3δ or CD3ɛ). The congenital absence of TCR components has a differential impact on T-cell development and function depending on the affected TCR chain and on the species, with human patients being, in some cases, rather different from mouse counterparts.The study of the immunophenotype by flow cytometry, along with molecular analyses, provides essential information for diagnosis and treatment, which is still to date the transplant of hematopoietic progenitors in severe immunodeficiency associated cases.

SAP modulates B cell functions in a genetic background-dependent manner

Mutations affecting the SLAM-associated protein (SAP) are responsible for the X-linked lympho-proliferative syndrome (XLP), a severe primary immunodeficiency syndrome with disease manifestations that include fatal mononucleosis, B cell lymphoma and dysgammaglobulinemia. It is well accepted that insufficient help by SAP−/− CD4+ T cells, in particular during the germinal center reaction, is a component of dysgammaglobulinemia in XLP patients and SAP−/− animals. It is however not well understood whether in XLP patients and SAP−/− mice B cell functions are affected, even though B cells themselves do not express SAP. Here we report that B cell intrinsic responses to haptenated protein antigens are impaired in SAP−/− mice and in Rag−/− mice into which B cells derived from SAP−/− mice together with wt CD4+ T cells had been transferred. This impaired B cells functions are in part depending on the genetic background of the SAP−/− mouse, which affects B cell homeostasis. Surprisingly, stimulation with an agonistic anti-CD40 causes strong in vivo and in vitro B cell responses in SAP−/− mice. Taken together, the data demonstrate that genetic factors play an important role in the SAP-related B cell functions. The finding that anti-CD40 can in part restore impaired B cell responses in SAP−/− mice, suggests potentially novel therapeutic interventions in subsets of XLP patients.

Involvement of microglial CD40 in murine retrovirus-induced peripheral neuropathy

B6 mice infected with LP-BM5 develop severe immunodeficiency (termed murine acquired immunodeficiency syndrome (MAIDS)) and peripheral neuropathy. To determine whether microglial CD40 is involved in LP-BM5-induced peripheral neuropathy, B6-CD40 knockout (KO) mice and B6-CD40 KO mice adoptively transferred either total leukocytes or B cells were examined for behavioral sensitivity, tissue viral loads, cytokine responses, and the development of MAIDS. All three CD40 KO groups developed MAIDS, the severity of which was correlated with peripheral cytokine responses. CD40 KO mice displayed significantly reduced mechanical hypersensitivity post-infection compared to wild-type mice regardless of cell transfer. These findings support microglial CD40 involvement in LP-BM5-induced peripheral neuropathy.

Foetal presentation of cartilage hair hypoplasia with extensive granulomatous inflammation

Cartilage-hair-hypoplasia is a rare autosomal recessive metaphyseal dysplasia due to RMRP (the RNA component of the RNase MRP ribonuclease mitochondrial RNA processing complex) gene mutations. So far, about 100 mutations have been reported in the promoter and the transcribed regions. Clinical characteristics include short-limbed short stature, sparse hair and defective cell-mediated immunity. We report herein the antenatal presentation of a female foetus, in whom CHH was suspected from 23 weeks' gestation, leading to a medical termination of the pregnancy at 34 weeks gestation, and thereafter confirmed by morphological and molecular studies. Post-mortem examination confirmed short stature and limbs, and revealed thymic hypoplasia associated with severe CD4 T-cell immunodeficiency along with extensive non caseating epithelioid granulomas in almost all organs, which to our knowledge has been described only in five cases. Molecular studies evidenced on one allele the most frequently reported founder mutation NR_003051: g.70A>G, which is present in 92% of Finnish patients with Cartilage Hair Hypoplasia. On the second allele, a novel mutation consisting of a 10 nucleotide insertion at position −18 of the promoter region of the RMRP gene (M29916.1:g.726_727insCTCACTACTC) was detected. The founder mutation was inherited from the father, and the novel mutation from the mother. To our knowledge, this case report represents the first detailed foetal analysis described in the literature.