X-linked inhibitor of apoptosis (XIAP) deficiency: the spectrum of presenting manifestations beyond hemophagocytic lymphohistiocytosis.

X-linked inhibitor of apoptosis (XIAP) deficiency caused by mutations in BIRC4 was initially described in patients with X-linked lymphoproliferative syndrome (XLP) who had no mutations in SH2D1A. In the initial reports, EBV-associated hemophagocytic lymphohistiocytosis (HLH) was the predominant clinical phenotype. Among 25 symptomatic patients diagnosed with XIAP deficiency, we identified 17 patients who initially presented with manifestations other than HLH. These included Crohn-like bowel disease (n=6), severe infectious mononucleosis (n=4), isolated splenomegaly (n=3), uveitis (n=1), periodic fever (n=1), fistulating skin abscesses (n=1) and severe Giardia enteritis (n=1). Subsequent manifestations included celiac-like disease, antibody deficiency, splenomegaly and partial HLH. Screening by flow cytometry identified 14 of 17 patients in our cohort. However, neither genotype nor protein expression nor results from cell death studies were clearly associated with the clinical phenotype. Only mutation analysis can reliably identify affected patients. XIAP deficiency must be considered in a wide range of clinical presentations.

Successful SCT for Nijmegen breakage syndrome.

Nijmegen breakage syndrome (NBS) is characterized by chromosomal instability, radiation hypersensitivity, characteristic facial appearance, immunodeficiency and strong predisposition to lymphoid malignancy. Traditionally, NBS patients have not undergone hematopoietic SCT (HSCT) owing to concerns about increased toxicity. We therefore report on the HSCT experience in NBS patients in Europe. Six patients were transplanted either for resistant or secondary malignancy (four patients) or severe immunodeficiency (two patients). Five patients received reduced-intensity conditioning regimens. After a median follow-up of 2.2 years, five patients are alive and well. One patient who received myeloablative conditioning died from sepsis before engraftment. Acute GVHD grades I-II occurred in three of five patients, mild chronic GVHD in one. All five surviving patients exhibit restored T-cell immunity. The experience in these six patients suggests that HSCT in NBS is feasible, can correct the immunodeficiency and effectively treat malignancy. Acute toxicity seems to be reasonable with reduced-intensity conditioning regimens.

Rituximab for the treatment of autoimmune cytopenias in children with immune deficiency.

Autoimmune cytopenias are well recognised in patients with primary immune deficiency, but treatment may be difficult. We report eight children with autoimmune cytopenias (autoimmune haemolytic anaemia, autoimmune thrombocytopenia, autoimmune neutropenia) complicating immune deficiency states (common variable immunodeficiency, Wiskott-Aldrich Syndrome, autoimmune lymphoproliferative syndrome, combined immunodeficiency) treated with between 1 and 3 courses of rituximab (anti-CD20). Responses occurred for 90% of treatments but relapse rates (after a median of 53 weeks) were high (78%). We conclude that rituximab is an effective treatment for autoimmune cytopenias in children with immune deficiencies, but repeated courses of treatment may be needed.

Cutaneous and other lupus-like symptoms in carriers of X-linked chronic granulomatous disease: incidence and autoimmune serology.

The objective of this study was to determine the utility of anti-nuclear antibody (ANA) testing in the investigation of cutaneous and other lupus symptoms in female carriers of X-linked chronic granulomatous disease (CGD). We undertook a prospective study of 19 carrier mothers attending our institution, with direct questioning of carriers concerning symptoms and testing for anti-nuclear and anti-phospholipid antibodies. A total of 58% reported significant photosensitive skin rashes, 42% reported mouth ulcers and 37% complained of joint pains that could not be attributed to other known causes. Anti-nuclear antibody (ANA) testing was negative in 73% of all carriers. The five positive ANAs were of low titre (maximum 1 : 320 on Hep 2 cells in two women) and only one weak positive double-stranded DNA antibody and no extractable nuclear antibodies were found. Several of the mothers, despite negative serology, benefited from referral to a specialist, and in some cases to specific treatment. A history of skin rashes, joint pain, fatigue and mouth ulcers should be sought actively in the female relatives of X-CGD patients but negative lupus serology should not preclude referral to appropriate dermatology or rheumatology services. as symptoms may respond well to appropriate treatment.

Nijmegen breakage syndrome diagnosed as Fanconi anaemia.

BACKGROUND: Fanconi anaemia (FA) and Nijmegen breakage syndrome (NBS) are rare chromosomal instability disorders with overlapping clinical features. It has recently been shown that, like FA, NBS is also associated with increased chromosomal sensitivity to DNA cross-linking agents. PROCEDURE: We report a family that was initially diagnosed with FA on the basis of increased sensitivity to DNA cross-linking agents. They were atypical in that there were associated severe infection problems. In view of these features we performed immune function studies together with molecular analysis of the FA genes and subsequently the NBS1 gene. RESULTS: Two children in the kindred have died, one from sepsis, and the other with a plasma cell malignancy. A third child underwent bone marrow transplantation because of recurrent infections. All affected members had severe immunological abnormalities. The genetic defect was shown to be a novel mutation in the NBS1 gene, so the diagnosis was revised to that of NBS. CONCLUSIONS: This family illustrates the importance of awareness of the lack of specificity of DNA cross-linking agent tests for FA, particularly in situations where the clinical features are atypical. In addition, one of the cases represents the first use of bone marrow transplantation for NBS that we are aware of; this treatment may have a future role for other patients with the syndrome.

Immunological and genetic analysis of 65 patients with a clinical suspicion of X linked hyper-IgM.

BACKGROUND: X linked hyper-IgM (XHIM) is a primary immunodeficiency caused by mutations in the tumour necrosis factor superfamily 5 gene, TNFSF5, also known as the CD40 ligand (CD40L) gene. Patients often present with recurrent infections, and confirmation of a diagnosis of XHIM enables appropriate therapeutic interventions, including replacement immunoglobulin, antibiotics, and bone marrow transplantation. AIM: To review and optimise the institution's diagnostic strategy for XHIM. METHOD: Samples from 65 boys were referred to this centre for further investigation of suspected XHIM. The results, which included a flow cytometric whole blood assay for CD40L expression followed by mutation analysis in selected patients, were reviewed. RESULTS: Twenty one patients failed to express CD40L and TNFSF5 mutations were found in 20 of these patients. In contrast, no TNFSF5 mutations were found in 16 patients with weak expression of CD40L. Interestingly, one quarter of patients with confirmed XHIM who had TNFSF5 mutations had low concentrations of IgG, IgA, and IgM. Most of the remaining patients with XHIM had the classic pattern of normal or raised IgM with low concentrations of IgA and IgG. CONCLUSIONS: This study demonstrates the usefulness of the whole blood staining method as a rapid screen to select patients for subsequent TNFSF5 mutation analysis, and shows the benefits of a unified protein/genetic diagnostic strategy.

Follow up of patients with chronic granulomatous disease diagnosed since 1990.

Outcomes for children with chronic granulomatous disease (CGD) have historically been poor, but significant improvements have occurred with the use of effective antibacterial prophylaxis. The present study aimed to document the clinical course of a cohort of children diagnosed with CGD since 1990 in a single centre. Twenty-one patients were identified, with a median age at last assessment of 4 years and 5 months. A third of these children were diagnosed in infancy because of a positive family history. Of the remaining, there was a median delay between the onset of symptoms and diagnosis of 13 months. No invasive or fungal infections were documented after diagnosis, nor were there any deaths in this cohort. A variety of non-infectious complications were noted, which responded well to steroids. As a group, these children were thriving and weight and height distributions fell within the population norm. All patients were receiving antibacterial prophylaxis, 90% with co-trimoxazole, and all but one patient were receiving a prophylactic anti-fungal agent (itraconazole). Both drugs were well tolerated. In conclusion, this cohort of patients, diagnosed in the last decade, tolerated antibacterial and anti-fungal prophylaxis well and on this regimen have a significantly decreased incidence of infection when compared with historical cohorts. Careful follow up of patients who have had aggressive antibacterial and anti-fungal prophylaxis should continue. The data reported on this cohort of patients should inform the debate about the use of more aggressive treatments, such as bone marrow transplantation, in this disease.

Inflammatory mediators in human renal dysplasia.

BACKGROUND: Cytokines regulate many processes in the immune system and have recently been implicated in normal organogenesis. We previously demonstrated that the archetypal inflammatory cytokine tumour necrosis factor-alpha (TNF-alpha) is expressed in the murine metanephros, and exogenous TNF-alpha inhibits nephrogenesis and increases macrophage numbers in vitro (Cale et al., Int J Dev Biol 1998; 42: 663-674). The phenotype seen, with an arrest of ureteric bud branching and failure of mesenchymal to epithelial conversion, is similar to human renal dysplasia. Methods and results. In normal human fetal kidneys we demonstrated the presence of macrophages and T cells and also documented TNF receptor expression on ureteric bud derivatives. In contrast to normal tissues, TNF-alpha protein was detected in dysplastic kidneys. This factor was also detected in the urine of fetuses with obstructive uropathy and TNF receptors were expressed in dysplastic tubules. Furthermore, we noted a fetal distribution of macrophages and T cells in dysplastic tissues and persistent expression of the adhesion molecules neural cell adhesion molecule and intercellular adhesion molecule. CONCLUSIONS: We suggest that abnormal expression of cytokines early in renal development dysregulates normal patterns of adhesion molecule expression and inflammatory cells, and may contribute to the pathogenesis of renal dysplasia.

Cytokines and macrophages: implications for normal and abnormal renal development.

Work with transgenic animals and in vitro manipulation of organs in culture has highlighted an increasing number of genes that are important in the normal development of the kidney and whose disruption inhibits nephrogenesis. The phenotype seen with some agents resembles that of the congenital renal anomaly renal dysplasia, in which there appears to be an arrest of normal development. Such molecules include inflammatory cytokines, factors that have traditionally been described as intercellular messengers in the immune system. Although the mechanisms of action of cytokines in organogenesis have not yet been fully delineated, these may include alterations in normal expression patterns of adhesion molecules, modulation of extracellular matrix, influencing the levels of other cytokines and interactions with transcription factors. Furthermore, macrophages are among the first haematopoietic cells to be found in the kidney and other embryonic tissues. Their numbers and activation status are closely regulated by cytokines and evidence is accumulating that as well as scavenging cellular debris, macrophages themselves may induce cell death during organogenesis. Disruption of any of these carefully regulated and interdependent processes may cause disease.

Tumor necrosis factor-alpha inhibits epithelial differentiation and morphogenesis in the mouse metanephric kidney in vitro.

Tumor necrosis factor-alpha (TNF-alpha), an inflammatory cytokine, has diverse actions both within and outside the immune system and has been implicated in the etiology of a wide range of pathological conditions. Evidence is accumulating that it may also have important roles in the normal development of the embryo. In this study we demonstrated that the addition of recombinant TNF-alpha to metanephric organ culture induced a dose dependent and reversible decrease in growth and development, with inhibition of ureteric bud branching and nephron formation beyond the condensate stage and despite appropriate expression of the transcription factor pax-2. TNF-alpha also increased the point prevalence of apoptosis after only 1 day of culture. We also noted that macrophages were present in renal rudiments at the inception of nephrogenesis and their numbers significantly increased during the culture period. This effect was enhanced by TNF-alpha. We have also demonstrated expression of mRNAs for TNF-alpha and its receptors in whole mouse metanephroi from the inception of renal development. TNF-alpha protein was also detected, predominantly at mesenchymal/epithelial interfaces. In addition, TNF-alpha mRNA and protein were expressed by clonal renal mesenchymal cells in vitro, suggesting that these cells are a source of TNF-alpha in vivo.

Severe combined immunodeficiency with abnormalities in expression of the common leucocyte antigen, CD45.

Children presenting with disseminated viral infections should be carefully investigated because they almost invariably have an underlying immunodeficiency. A child is reported who had disseminated cytomegalovirus and a novel form of severe combined immunodeficiency with abnormal expression of the common leucocyte antigen, CD45.

Roles of growth factors in renal development.

The branching of the ureteric bud and the differentiation of renal mesenchyme into nephrons are interdependent processes. Experiments with organ culture and genetically engineered mice suggest that metanephric growth factors regulate these events. Renal mesenchyme produces glial cell line-derived neurotrophic factor, an essential molecule for ureteric bud growth, whereas multiple growth factors are required for nephron formation: these include fibroblast growth factor 2, Wnt4 and bone morphogenetic protein 7. Deregulation of growth factors may be implicated in the pathogenesis of congenital kidney malformations.