Immunodeficiency, autoinflammation and amylopectinosis in humans with inherited HOIL-1 and LUBAC deficiency.

We report the clinical description and molecular dissection of a new fatal human inherited disorder characterized by chronic autoinflammation, invasive bacterial infections and muscular amylopectinosis. Patients from two kindreds carried biallelic loss-of-expression and loss-of-function mutations in HOIL1 (RBCK1), a component of the linear ubiquitination chain assembly complex (LUBAC). These mutations resulted in impairment of LUBAC stability. NF-κB activation in response to interleukin 1ß (IL-1ß) was compromised in the patients' fibroblasts. By contrast, the patients' mononuclear leukocytes, particularly monocytes, were hyper-responsive to IL-1ß. The consequences of human HOIL-1 and LUBAC deficiencies for IL-1ß responses thus differed between cell types, consistent with the unique association of autoinflammation and immunodeficiency in these patients. These data suggest that LUBAC regulates NF-κB-dependent IL-1ß responses differently in different cell types.

Long-term outcome and lineage-specific chimerism in 194 patients with Wiskott-Aldrich syndrome treated by hematopoietic cell transplantation in the period 1980-2009: an international collaborative study.

In this retrospective collaborative study, we have analyzed long-term outcome and donor cell engraftment in 194 patients with Wiskott-Aldrich syndrome (WAS) who have been treated by hematopoietic cell transplantation (HCT) in the period 1980- 2009. Overall survival was 84.0% and was even higher (89.1% 5-year survival) for those who received HCT since the year 2000, reflecting recent improvement of outcome after transplantation from mismatched family donors and for patients who received HCT from an unrelated donor at older than 5 years. Patients who went to transplantation in better clinical conditions had a lower rate of post-HCT complications. Retrospective analysis of lineage-specific donor cell engraftment showed that stable full donor chimerism was attained by 72.3% of the patients who survived for at least 1 year after HCT. Mixed chimerism was associated with an increased risk of incomplete reconstitution of lymphocyte count and post-HCT autoimmunity, and myeloid donor cell chimerism < 50% was associated with persistent thrombocytopenia. These observations indicate continuous improvement of outcome after HCT for WAS and may have important implications for the development of novel protocols aiming to obtain full correction of the disease and reduce post-HCT complications.

Transplantation of hematopoietic stem cells and long-term survival for primary immunodeficiencies in Europe: entering a new century, do we do better?

BACKGROUND: Hematopoietic stem cell transplantation remains the only treatment for most patients with severe combined immunodeficiencies (SCIDs) or other primary immunodeficiencies (non-SCID PIDs). OBJECTIVE: To analyze the long-term outcome of patients with SCID and non-SCID PID from European centers treated between 1968 and 2005. METHODS: The product-limit method estimated cumulative survival; the log-rank test compared survival between groups. A Cox proportional-hazard model evaluated the impact of independent predictors on patient survival. RESULTS: In patients with SCID, survival with genoidentical donors (n = 25) from 2000 to 2005 was 90%. Survival using a mismatched relative (n = 96) has improved (66%), similar to that using an unrelated donor (n = 46; 69%; P = .005). Transplantation after year 1995, a younger age, B(+) phenotype, genoidentical and phenoidentical donors, absence of respiratory impairment, or viral infection before transplantation were associated with better prognosis on multivariate analysis. For non-SCID PID, in contrast with patients with SCID, we confirm that, in the 2000 to 2005 period, using an unrelated donor (n = 124) gave a 3-year survival rate similar to a genoidentical donor (n = 73), 79% for both. Survival was 76% in phenoidentical transplants (n = 23) and worse in mismatched related donor transplants (n = 47; 46%; P = .016). CONCLUSION: This is the largest cohort study of such patients with the longest follow-up. Specific issues arise for different patient groups. Patients with B-SCID have worse survival than other patients with SCID, despite improvements in each group. For non-SCID PID, survival is worse than SCID, although more conditions are now treated. Individual disease categories now need to be analyzed so that disease-specific prognosis may be better understood and the best treatments planned.

Clinical and immunologic outcome of patients with cartilage hair hypoplasia after hematopoietic stem cell transplantation.

Cartilage-hair hypoplasia (CHH) is a rare autosomal recessive disease caused by mutations in the RMRP gene. Beside dwarfism, CHH has a wide spectrum of clinical manifestations including variable grades of combined immunodeficiency, autoimmune complications, and malignancies. Previous reports in single CHH patients with significant immunodeficiencies have demonstrated that allogeneic hematopoietic stem cell transplantation (HSCT) is an effective treatment for the severe immunodeficiency, while growth failure remains unaffected. Because long-term experience in larger cohorts of CHH patients after HSCT is currently unreported, we performed a European collaborative survey reporting on 16 patients with CHH and immunodeficiency who underwent HSCT. Immune dysregulation, lymphoid malignancy, and autoimmunity were important features in this cohort. Thirteen patients were transplanted in early childhood ( approximately 2.5 years). The other 3 patients were transplanted at adolescent age. Of 16 patients, 10 (62.5%) were long-term survivors, with a median follow-up of 7 years. T-lymphocyte numbers and function have normalized, and autoimmunity has resolved in all survivors. HSCT should be considered in CHH patients with severe immunodeficiency/autoimmunity, before the development of severe infections, major organ damage, or malignancy might jeopardize the outcome of HSCT and the quality of life in these patients.

A single-center experience in 20 patients with infantile malignant osteopetrosis.

Infantile malignant osteopetrosis (IMO) includes various genetic disorders that affect osteoclast development and/or function. Genotype-phenotype correlation studies in IMO have been hampered by the rarity and heterogeneity of the disease and by the severity of the clinical course, which often leads to death early in life. We report on the clinical and molecular findings and treatment in 20 consecutive patients (11 males, nine females) with IMO, diagnosed at a single center in the period 1991-2008. Mean age at diagnosis was 3.9 months, and mean follow-up was 66.75 months. Mutations in TCIRG1, OSTM1, ClCN7, and TNFRSF11A genes were detected in nine, three, one, and one patients, respectively. Six patients remain genetically undefined. OSTM1 and ClCN7 mutations were associated with poor neurologic outcome. Among nine patients with TCIRG1 defects, six presented with hypogammaglobulinemia, and one showed primary pulmonary hypertension. Fourteen patients received hematopoietic cell transplantation; of these, nine are alive and eight of them have evidence of osteoclast function. These data may provide a basis for informed decisions regarding the care of patients with IMO.

Single-center analysis of long-term outcome after hematopoietic cell transplantation in children with congenital severe T cell immunodeficiency.

We review clinical outcome and immune reconstitution in a consecutive series of 74 infants with severe T cell immunodeficiency who received hematopoietic cell transplantation (HCT) from January 1991 to May 2003. Fifty-three patients (71.6%) are alive. Results were significantly better for recipients of HCT from HLA-matched related donors (100% survival) and unrelated donors (86.4%) than from mismatched related donors (51.6%). A detailed analysis of immune reconstitution and clinical status was performed in 49 surviving patients, most of which have attained robust T and B cell reconstitution and are in very good clinical conditions. No cases of late deaths or of chronic graft-versus-host disease (GvHD) have been observed. However, infections and autoimmunity at >1 year after HCT have been observed in a significant number of patients. Persistence of a low number of circulating naive T cells and long-term requirement for intravenous immunoglobulin were associated with a higher incidence of clinical events.

Variability of clinical and laboratory features among patients with ribonuclease mitochondrial RNA processing endoribonuclease gene mutations.

BACKGROUND: Cartilage hair hypoplasia is an autosomal recessive type of metaphyseal chondrodysplasia, caused by mutations in the ribonuclease mitochondrial RNA processing (RMRP) gene. Typical features of cartilage hair hypoplasia include short stature, a predisposition to malignancy, and a variable degree of impairment of cellular immunity. OBJECTIVE: We sought to describe the heterogeneity of clinical and immunologic phenotype in 12 consecutive patients with RMRP mutations who were referred to 2 different institutions for immunologic evaluation. METHODS: We have retrospectively analyzed the clinical and laboratory features in 12 patients with molecular defects in the RMRP gene. T-cell repertoire was investigated by quantitating Vbeta families' expression and analyzing their diversity. T-cell receptor excision circle analysis was used to study thymic output. RESULTS: All 12 patients had significant immune abnormalities, leading to severe immune deficiency in 9. CD8 lymphocytopenia was identified as a novel phenotype associated with RMRP mutations. Significant, even intrafamilial, phenotypic heterogeneity was observed. In 3 cases, severe immunodeficiency was the only phenotypic manifestation associated with RMRP mutations, a novel finding. Mutations leading to significant immune defects were most often located in the promoter, and the first case of a compound heterozygote for 2 such mutations is reported. CONCLUSION: This report broadens the spectrum of phenotypes associated with RMRP mutations and suggests that mutations in this gene should be considered when evaluating patients with combined immune deficiency, regardless of the presence of other manifestations.

Human osteoclast-poor osteopetrosis with hypogammaglobulinemia due to TNFRSF11A (RANK) mutations.

Autosomal-Recessive Osteopetrosis (ARO) comprises a heterogeneous group of bone diseases for which mutations in five genes are known as causative. Most ARO are classified as osteoclast-rich, but recently a subset of osteoclast-poor ARO has been recognized as due to a defect in TNFSF11 (also called RANKL or TRANCE, coding for the RANKL protein), a master gene driving osteoclast differentiation along the RANKL-RANK axis. RANKL and RANK (coded for by the TNFRSF11A gene) also play a role in the immune system, which raises the possibility that defects in this pathway might cause osteopetrosis with immunodeficiency. From a large series of ARO patients we selected a Turkish consanguineous family with two siblings affected by ARO and hypogammaglobulinemia with no defects in known osteopetrosis genes. Sequencing of genes involved in the RANKL downstream pathway identified a homozygous mutation in the TNFRSF11A gene in both siblings. Their monocytes failed to differentiate in vitro into osteoclasts upon exposure to M-CSF and RANKL, in keeping with an osteoclast-intrinsic defect. Immunological analysis showed that their hypogammaglobulinemia was associated with impairment in immunoglobulin-secreting B cells. Investigation of other patients revealed a defect in both TNFRSF11A alleles in six additional, unrelated families. Our results indicate that TNFRSF11A mutations can cause a clinical condition in which severe ARO is associated with an immunoglobulin-production defect.

Long-term outcome following hematopoietic stem-cell transplantation in Wiskott-Aldrich syndrome: collaborative study of the European Society for Immunodeficiencies and European Group for Blood and Marrow Transplantation.

Wiskott-Aldrich syndrome (WAS) is a rare X-linked immunodeficiency with microthrombocytopenia, eczema, recurrent infections, autoimmune disorders, and malignancies that are life-threatening in the majority of patients. In this long-term, retrospective, multicenter study, we analyzed events that occurred in 96 WAS patients who received transplants between 1979 and 2001 who survived at least 2 years following hematopoietic stem-cell transplantation (HSCT). Events included chronic graft-versus-host disease (cGVHD), autoimmunity, infections, and sequelae of before or after HSCT complications. Three patients (3%) died 2.1 to 21 years following HSCT. Overall 7-year event-free survival rate was 75%. It was lower in recipients of mismatched related donors, also in relation with an older age at HSCT and disease severity. The most striking finding was the observation of cGVHD-independent autoimmunity in 20% of patients strongly associated with a mixed/split chimerism status (P < .001), suggesting that residual-host lymphocytes can mediate autoimmune disease despite the coexistence of donor lymphocytes. Infectious complications (6%) related to splenectomy were also significant and may warrant a more restrictive approach to performing splenectomy in WAS patients. Overall, this study provides the basis for a prospective, standardized, and more in-depth detailed analysis of chimerism and events in long-term follow-up of WAS patients who receive transplants to design better-adapted therapeutic strategies.

Lack of iNKT cells in patients with combined immune deficiency due to hypomorphic RAG mutations.

Hypomorphic mutations of the RAG genes in humans are associated with a spectrum of clinical and immunologic presentations that range from T(-) B(-) severe combined immune deficiency (SCID) to Omenn syndrome. In most cases, residual V(D)J recombination activity allows for development of few T-cell clones, which expand in the periphery and infiltrate target organs, resulting in tissue damage. Invariant natural killer T (iNKT) cells play an important immunoregulatory role and have been associated with protection against autoimmunity. We now report on 5 unrelated cases of combined immune deficiency due to hypomorphic RAG mutations, and demonstrate the absence of iNKT cells in all 5 patients. These findings suggest that lack of this important immunoregulatory cell population may contribute to the pathophysiology of Omenn syndrome.

Long-term immune reconstitution and clinical outcome after stem cell transplantation for severe T-cell immunodeficiency.

BACKGROUND: Currently, hematopoietic stem cell transplantation allows long-term survival in a high proportion of infants with congenital severe T-cell immunodeficiency. However, relatively little is known of their long-term quality of life. OBJECTIVE: We sought to assess the long-term immune reconstitution and clinical status in children treated with stem cell transplantation for severe T-cell immunodeficiency. METHODS: Immune function and clinical status have been analyzed in a cohort of 40 patients with severe T-cell immunodeficiency who are alive at a follow-up of at least 5 years after transplantation. RESULTS: Most patients have attained normal T- and B-cell function. Weight and height were normal at last follow-up in most patients. Endocrine and severe neurologic abnormalities have been observed in 17.5% and 10% of the patients, respectively. CONCLUSIONS: These data indicate that with current management strategies, stem cell transplantation can lead to long-term survival and good quality of life in the majority of patients with severe T-cell immunodeficiency. CLINICAL IMPLICATIONS: Prompt recognition of congenital severe T-cell immunodeficiency, followed by stem cell transplantation, allows excellent perspectives of long-term survival and good quality of life for these otherwise fatal disorders.

Genetic causes of bronchiectasis: primary immune deficiencies and the lung.

Primary immune deficiencies (PID) comprise a heterogeneous group of genetically determined disorders that affect development and/or function of innate or adaptive immunity. Consequently, patients with PID suffer from recurrent and/or severe infections that frequently involve the lung. While the nature of the immune defect often dictates the type of pathogens that may cause lung infection, there is substantial overlap of radiological findings, so that appropriate laboratory tests are mandatory to define the nature of the immune defect and to prompt appropriate treatment. At the same time, the recent identification of a large number of PID-causing genes now allows early, even presymptomatic diagnosis, thus representing an essential tool for prevention of lung damage. This review article describes the most common forms of PID, their cellular and molecular bases, and the associated lung abnormalities, and reports on available treatment.

The Wiskott-Aldrich syndrome: from genotype-phenotype correlation to treatment.

Development of patient-tailored prognostic and therapeutic strategies remains a major, yet largely unmet, goal of medicine. Studies performed in patients who carry mutations in the Wiskott-Aldrich syndrome protein (WASP) gene have indicated the feasibility, but also the limitations, of this approach. In this review, we discuss the importance of specific WASP mutations, and their effects on protein expression and function in determining the spectrum of clinical phenotypes associated with WASP defects. The array of currently available and foreseeable therapeutic options is reviewed in this context as a model for other more common genetic disorders.

Stem cell transplantation in primary immunodeficiencies.

PURPOSE OF REVIEW: To review indications and outcomes of haematopoietic stem cell transplantation in primary immunodeficiencies, in light of recent advances in the field. RECENT FINDINGS: Remarkable improvements in the outcome of haematopoietic stem cell transplantation in primary immunodeficiencies have recently been reported. This is a result of the successful use of alternative donors and more effective strategies to prevent and treat complications. These advances have now permitted the indications for haematopoietic stem cell transplantation to be extended in primary immunodeficiencies. SUMMARY: The optimal results of haematopoietic stem cell transplantation in primary immunodeficiencies have long been obtained with related human leukocyte antigen-identical donors, an option limited to a minority of patients. Transplantation from mismatched related donors has been used with good results mainly in infants with severe combined immune deficiency, but has been associated with significantly delayed or incomplete immune reconstitution. Recent data indicate that transplantation from matched unrelated donors and cord blood transplantation represent valid alternatives, which can be used in all forms of severe primary immunodeficiencies. This, along with careful monitoring of infections, coupled with preemptive treatment, has resulted in a significant improvement in the outcome of haematopoietic stem cell transplantation for severe forms of primary immunodeficiencies.

Bone marrow transplantation for severe combined immune deficiency.

CONTEXT: Bone marrow transplantation (BMT) using stem cells obtained from a family-related, HLA-identical donor (RID) is the optimal treatment for patients with severe combined immune deficiency (SCID). In the absence of an RID, HLA-mismatched related donors (MMRDs) are often used. However, compared with RIDs, use of MMRDs for BMT is associated with reduced survival and inferior long-term immune reconstitution. Use of HLA-matched unrelated donors (MUDs) represents another potential alternative for BMT. OBJECTIVE: To compare outcomes and immune reconstitution in a large cohort of patients with SCID who received RID, MUD, or MMRD BMT. DESIGN, SETTING, AND PATIENTS: Retrospective study of medical records from 94 infants diagnosed as having SCID who received BMT between 1990 and 2004 at 1 Canadian and 1 Italian pediatric referral center. Thirteen, 41, and 40 patients received RID, MUD, and MMRD BMT, respectively. MAIN OUTCOME MEASURES: Survival and graft failure, along with incidence of graft-vs-host disease, infections, and other complications; immune reconstitution was assessed in children who survived for more than 2 years after BMT. RESULTS: Survival after RID BMT was highest. Twelve (92.3%) of 13 patients who received RID BMT, 33 (80.5%) of 41 who received MUD BMT, and 21 (52.5%) of 40 patients who received MMRD BMT survived. Compared with MMRD BMT, survival was significantly higher with RID (P = .008) or with MUD (P = .03). Graft failures and need for repeat BMT were more common in patients receiving MMRD BMT than in those who underwent MUD BMT. Long-term reconstitution of a full T-cell repertoire was achieved more frequently following MUD BMT (94.7%) than after MMRD BMT (61.1%) (P = .02). Acute graft-vs-host disease was documented in 73.1% of patients following MUD BMT but in only 45% after MMRD BMT (P = .009). Conversely, interstitial pneumonitis was observed more frequently after MMRD BMT (14 [35.0%] of 40) than after MUD BMT (3 [7.3%] of 41; P = .002). CONCLUSION: Our study suggests that in the absence of a relative with identical HLA, MUD BMT may provide better engraftment, immune reconstitution, and survival for patients with SCID than MMRD BMT.

Cytokine-mediated signalling and early defects in lymphoid development.

PURPOSE OF REVIEW: The aim of the review is to report on recent advances in cytokine-mediated signalling, as illustrated by the study of natural human mutants. In particular, the role of cytokines and cytokine-mediated signalling in human T-cell development is analysed in detail, and currently available forms of treatment including experimental trials are described. RECENT FINDINGS: Defects of the cytokine/JAK/STAT axis have been recently described as responsible for human Severe Combined Immune Deficiency. In particular, defects in gammac, JAK3 and IL7RA have been analysed in terms of development of novel diagnostic tools as well as of new therapeutic agents for the treatment of autoimmune diseases and graft-versus-host disease. SUMMARY: Dissection of the genetic defects underlying the various forms of Severe Combined Immune Deficiency has helped develop new and more accurate diagnostic assays and novel forms of treatment.

AIRE deficiency in thymus of 2 patients with Omenn syndrome.

Omenn syndrome is a severe primary immunodeficiency with putative autoimmune manifestations of the skin and gastrointestinal tract. The disease is caused by hypomorphic mutations in recombination-activating genes that impair but do not abolish the process of VDJ recombination, leading to the generation of autoreactive T cells with a highly restricted receptor repertoire. Loss of central tolerance in genetically determined autoimmune diseases, e.g., autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy, is associated with defective expression by medullary thymic epithelial cells of AIRE, the transcription activator that induces thymic expression of tissue-specific antigens. Analysis of AIRE expression in the thymi of 2 Omenn syndrome patients and 1 SCID patient, by real-time RT-PCR and immunohistochemistry, demonstrated a profound reduction in the levels of AIRE mRNA and protein in patients as compared with a normal control subject. Lack of AIRE was associated with normal or even increased levels of keratin and lymphotoxin-beta receptor mRNAs, while mRNAs of the self-antigens insulin, cytochrome P450 1a2, and fatty acid-binding protein were undetectable in thymi from immunodeficiency patients. These results demonstrate that deficiency of AIRE expression is observed in severe immunodeficiencies characterized by abnormal T cell development and suggest that in Omenn syndrome, the few residual T cell clones that develop may escape negative selection and thereafter expand in the periphery, causing massive autoimmune reactions.