Clinical spectrum of immunodeficiency, centromeric instability and facial dysmorphism (ICF syndrome).

BACKGROUND: Immunodeficiency, centromeric instability and facial dysmorphism (ICF syndrome) is a rare autosomal recessive disease characterised by facial dysmorphism, immunoglobulin deficiency and branching of chromosomes 1, 9 and 16 after PHA stimulation of lymphocytes. Hypomethylation of DNA of a small fraction of the genome is an unusual feature of ICF patients which is explained by mutations in the DNA methyltransferase gene DNMT3B in some, but not all, ICF patients. OBJECTIVE: To obtain a comprehensive description of the clinical features of this syndrome as well as genotype-phenotype correlations in ICF patients. METHODS: Data on ICF patients were obtained by literature search and additional information by means of questionnaires to corresponding authors. RESULTS AND CONCLUSIONS: 45 patients all with proven centromeric instability were included in this study. Facial dysmorphism was found to be a common characteristic (n = 41/42), especially epicanthic folds, hypertelorism, flat nasal bridge and low set ears. Hypo- or agammaglobulinaemia was demonstrated in nearly all patients (n = 39/44). Opportunistic infections were seen in several patients, pointing to a T cell dysfunction. Haematological malignancy was documented in two patients. Life expectancy of ICF patients is poor, especially those with severe infections in infancy or chronic gastrointestinal problems and failure to thrive. Early diagnosis of ICF is important since early introduction of immunoglobulin supplementation can improve the course of the disease. Allogeneic stem cell transplantation should be considered as a therapeutic option in patients with severe infections or failure to thrive. Only 19 of 34 patients showed mutations in DNMT3B, suggesting genetic heterogeneity. No genotype-phenotype correlation was found between patients with and without DNMT3B mutations.

Long-term outcome of haematopoietic stem cell transplantation in autosomal recessive osteopetrosis: an EBMT report.

A retrospective analysis was made of 122 children who had received an allogeneic haematopoietic stem cell transplantation (HSCT) for autosomal recessive osteopetrosis between 1980 and 2001. The actuarial probabilities of 5 years disease free survival were 73% for recipients of a genotype HLA-identical HSCT (n=40), 43% for recipients of a phenotype HLA-identical or one HLA-antigen mismatch graft from a related donor (n=21), 40% for recipients of a graft from a matched unrelated donor (n=20) and 24% for patients who received a graft from an HLA-haplotype-mismatch related donor (n=41). In the latter group, a trend towards improvement was achieved at the end of the study period (17% before 1994, 45% after 1994, P=0.11). Causes of death after HSCT were graft failure and early transplant-related complications. Severe visual impairment was present in 42% of the children before HSCT. Conservation of vision was better in children transplanted before the age of 3 months. Final height was related to height at the time of HSCT and better preserved in children transplanted early. Most children attended regular school or education for the visually handicapped. At present, HSCT is the only curative treatment for autosomal recessive osteopetrosis and should be offered as early as possible.

Formation of non-resorbing osteoclasts from peripheral blood mononuclear cells of patients with malignant juvenile osteopetrosis.

The genetic defects that cause human infantile malignant osteopetrosis, a disease with recessive inheritance characterized by lack of bone resorption and the presence of large numbers of inactive osteoclasts, are only partially known. Studies of osteoclasts in vitro may help to identify or exclude candidate genes in this disorder. Here, we established co-cultures of peripheral blood mononuclear cells with mouse fetal bone rudiments to generate osteoclasts from three infants with malignant osteopetrosis. Osteoclasts generated in vitro displayed the same inability to form ruffled borders and resorb bone as seen in bone biopsies. This culture model may contribute to understanding the pathogenesis of this disease.

Unexpected and variable phenotypes in a family with JAK3 deficiency.

Mutations of the Janus kinase 3 (JAK3) have been previously described to cause an autosomal recessive variant of severe combined immunodeficiency (SCID) usually characterized by the near absence of T and NK cells, but preserved numbers of B lymphocytes (T-B+SCID). We now report a family whose JAK3 mutations are associated with the persistence of circulating T cells, resulting in previously undescribed clinical presentations, ranging from a nearly unaffected 18-year-old subject to an 8-year-old sibling with a severe lymphoproliferative disorder. Both siblings were found to be compound heterozygotes for the same deleterious JAK3 mutations: an A96G initiation start site mutation, resulting in a dysfunctional, truncated protein product and a G2775(+3)C mutation in the splice donor site sequence of intron 18, resulting in a splicing defect and a predicted premature stop. These mutations were compatible with minimal amounts of functional JAK3 expression, leading to defective cytokine-dependent signaling. Activated T cells in these patients failed to express Fas ligand (FasL) in response to IL-2, which may explain the accumulation of T cells with an activated phenotype and a skewed T cell receptor (TcR) Vbeta family distribution. We speculate that residual JAK3 activity accounted for the maturation of thymocytes, but was insufficient to sustain IL-2-mediated homeostasis of peripheral T cells via Fas/FasL interactions. These data demonstrate that the clinical spectrum of JAK3 deficiency is quite broad and includes immunodeficient patients with accumulation of activated T cells, and indicate an essential role for JAK3 in the homeostasis of peripheral T cells in humans.

Early VEP and ERG evidence of visual dysfunction in autosomal recessive osteopetrosis.

Autosomal recessive (AR) osteopetrosis has a rapid course and manifests in the first months of life. Visual loss occurs because of optic nerve compromise, and more rarely retinal dysfunction (which may be a part of a primary neurodegeneration). The only curative treatment currently available is bone marrow transplantation (BMT). It has been suggested that BMT is contraindicated if AR osteopetrosis is associated with a primary neurodegeneration. Visual impairment tends to be irreversible after BMT. The young age of the patients makes reliable, objective tests of visual function especially important. We have reviewed the flash electroretinograms (ERGs) and flash and pattern visual evoked potentials (VEPs) recorded without sedation from 15 patients with AR osteopetrosis, 11 of whom were recorded longitudinally. The most frequent, early indication of visual dysfunction was a delay in the pattern or flash VEP latency. This first affects the pattern reversal VEP to small checks. Importantly this often preceded fundal changes of optic disc pallor, and evidence of optic nerve compression on neuroimaging. Only two patients had ERG evidence of retinal dysfunction affecting both rods and cones. One of these patients had a distinctive fundal appearance, but did not have evidence of associated neuronal degenerative disease. The other patient was lost to follow-up. In the patients reviewed in this study successful BMT and optic nerve decompression did not result in VEP improvement. Fundoscopy, VEP and ERG testing are indicated when the diagnosis of AR osteopetrosis is suspected and provide a useful means of monitoring visual involvement.

Osteopetrosis: pathogenesis and rationale for the use of interferon-γ-1b.

Congenital osteopetrosis is a group of disorders resulting in decreased osteoclastic function and hence decreased bone resorption. Various medical treatments have been attempted to ameliorate the osteopetrotic condition. A calcium-deficient diet has limited further sclerosis in some patients. Prednisone therapy has improved haematological function in some patients, but has not resulted in a reduction in bone mass. Calcitrophic hormones, such as parathyroid hormone (PTH) infusions and oral calcitriol, stimulate osteoclastic activity, and calcitriol in particular has stimulated osteoclastic bone resorption in some patients with osteopetrosis. Bone marrow transplantation, although curative, is limited by paucity of donors, risk of graft-versus-host disease and relapse of the disease. The demonstration of defective leucocyte superoxide production in osteopetrotic patients and the premise that osteoclasts appear to arise from the granulocyte macrophage lineage have led to attempts at treating osteopetrosis with immunomodulators. Since treatment with recombinant interferon-γ-1b (interferon γ-1b, IFNγ-1b) has resulted in increased level of superoxide generation and clinical improvement in chronic granulomatous disease, a similar strategy has been employed using IFNγ-1b to treat patients with osteopetrosis. IFNγ-1b has been demonstrated to increase osteoclastic bone resorption and leucocytic function. Long term therapy with IFNγ-1b by subcutaneous injection 3 times weekly resulted in marked clinical improvement, a decreased incidence of infections, a decreased trabecular bone mass, and an increased marrow space resulting in improved haemopoiesis. The therapy has been associated with few adverse effects, mainly fever and diarrhoea which have been managed with a reduction in IFNγ-1b dosage. The low-calcium diet occasionally results in hypocalcaemic tetany, which may be corrected by increased dietary calcium intake. Thus, IFNγ-1b has a distinct place in the therapeutic armamentarium for patients with osteopetrosis and is a feasible treatment option in such patients.

Risk factors for developing EBV-related B cell lymphoproliferative disorders (BLPD) after non-HLA-identical BMT in children.

B cell lymphoproliferative disorders (BLPD) are relatively frequent after genotypically non-HLA-identical BMT. We performed univariate analysis to study which BMT-related variables were associated with an increased risk of developing BLPD. Sixty-five recipients of other than genotypically HLA-identical BM grafts were included in the study. Seventy-seven recipients of genotypically HLA-identical BM grafts served as a comparison group. BLPD occurred in nine of 65 children after non-HLA-identical BMT (14%) and in none of the 77 children after HLA-identical BMT (0%). In all cases, BLPD was proven to be EBV-related. Our data suggest that the combined use of Campath 1G and anti-LFA1 was associated with an increased risk of developing BLPD, particularly children who had received a T cell-depleted BM graft, using albumen density gradient sedimentation followed by E-rosetting, and who were conditioned with Ara-C, CY and TBL. In addition, T cell numbers below 50/microliters at 1 month and below 100/microliters at 2 months after BMT, respectively, were associated with an increased risk of developing BLPD. Longitudinal determination of T cell numbers after non-HLA-identical BMT is a simple method for identifying patients at risk of developing BLPD. In addition to monitoring levels of circulating EBV-infected lymphocytes, monitoring T cell numbers may allow early intervention to prevent progression of BLPD.

Follow-up of leucocyte and reticulocyte counts for the prediction of early graft failure after non-HLA-identical BMT in children.

Allogeneic BMT using a non-genotypically HLA-identical donor may be curative for children suffering from lethal haematological diseases, who lack a genotypically HLA-identical donor. Unfortunately, graft failures are often seen, especially after T cell depletion of the graft. We studied whether untimely decreased counts of leucocytes and reticulocytes in peripheral blood might predict graft failure at an early stage. Fifty-five recipients of a non-genotypically HLA-identical BM graft were included in the study; data from these children were compared with those of 77 recipients of a genotypically HLA-identical BM graft. Time-related reference values of peripheral blood leucocyte and reticulocyte counts were established in graft recipients with proven donor-origin recovery after BMT. Graft failure after nonHLA-identical BMT was observed in 16 out of 55 children (29%) and after HLA-identical BMT in one out of 77 (1.3%). With respect to early graft failure, the predictive value of granulocyte numbers falling below the lower limit of the reference values and a rapid decline of reticulocyte numbers after their appearance in peripheral blood was 100% (95% confidence intervals of 83-100% and of 80-100%, respectively). Early immunosuppressive intervention was applied in six patients and was successful in three of them.

Search for the antigen-specificity of homogeneous IgG components (H-IgG) after allogeneic bone marrow transplantation.

After allogeneic BMT, transient homogeneous Ig components (H-Ig) can be detected in the sera of most graft recipients. So far, data on the antigen-specificity and therefore the function of these H-Ig are not available. Such information may be important for our understanding of the underlying mechanisms that are responsible for these excessive clonal B cell expansions, and it may help to delineate the functional antibody repertoire after BMT. In the present study, sera of 98 paediatric BM graft recipients were investigated for the potential presence of H-Ig of IgG isotype (H-IgG) with specificity towards a panel of antigens, including vaccine and herpes virus antigens, auto-antigens and allo-antigens. The vast majority of H-IgG in sera of BM graft recipients were unreactive when tested for this panel of antigens. However, in four cases, antigen-specificity of H-IgG to tetanus toxoid could be demonstrated after vaccination with that antigen. An explanation for the negative findings may be either that a restricted antibody production had been elicited by other non-tested antigens, eg substances of colonizing and translocating bacteria or of food antigens, or that the H-IgG components may have anti-idiotype or anti-'self' specificity.

The origin of IgG production and homogeneous IgG components after allogeneic bone marrow transplantation.

Pediatric recipients (n = 25) of an allogeneic bone marrow (BM) graft were selected on the basis of informative IgG allotype (Gm) differences between the BM donor and the recipient. To investigate the kinetics of the appearance of IgG of donor origin and the disappearance of IgG of recipient origin, G1m and G2m allotype levels were quantified in sera obtained at regular intervals between 3 months and 5 years after BM transplantation (BMT). For this quantification, a dot immunobinding assay (DIBA) has been developed. In 19 of 22 informative recipients, the Gm allotype distribution had reached the range of values expected on the basis of the Gm phenotype of the donor within 6 months after BMT. Remarkably, IgG of recipient origin persisted in 15 of 18 informative recipients until last follow up, ie, for several years after BMT. In addition to the origin of total IgG production, the origin of homogeneous IgG components (H-IgG) appearing after BMT was investigated. H-IgG of donor origin could be detected as early as 3 weeks after BMT, but also H-IgG of recipient origin were present in 8 of 13 informative recipients for a period of up to 1 year after BMT. We conclude that host-type IgG-producing cells were not eradicated by the (myeloablative) conditioning regimen and persisted in a high number of graft recipients. It is our hypothesis that lack of graft-versus-host disease (GVHD) in the majority of these recipients results in the persistence of IgG-producing cells of host origin. These observations may be relevant for the evaluation of patients who received allogeneic BMT for the treatment of multiple myeloma.

Case-control analysis of allogeneic bone marrow transplantation versus maintenance chemotherapy for relapsed ALL in children.

In a retrospective study, the results of maintenance chemotherapy and allogeneic bone marrow transplantation (BMT) for children who reached a second complete remission (CR2) of their acute lymphoblastic leukemia (ALL) were compared. Case-control analysis was performed comparing 25 allogeneic transplant patients (cases) with 97 patients treated with maintenance chemotherapy (controls), who were matched for site of relapse, duration of CR1 and leukemia-free interval from onset of CR2. Until the first relapse, the children were treated according to standard protocols. The majority of patients suffered from a bone marrow relapse, mostly occurring more than 24 months after the onset of CR1. Remission reinduction treatment was heterogeneous. Patients treated with allogeneic BMT received high-dose chemotherapy and total body irradiation prior to BMT. Maintenance chemotherapy in controls was given for approximately 2 years. Following BMT, relapse rate was lower but the treatment-related mortality was higher compared with maintenance chemotherapy, resulting in leukemia-free survival rates at 4 years of 44% and 24%, respectively (not significant, NS). Case-control analysis of leukemia-free survival showed a hazard ratio of 0.756 in favor of BMT compared with chemotherapy (NS). If bone marrow relapses and central nervous system relapses were analyzed separately, a tendency to better leukemia-free survival was present after BMT compared with maintenance chemotherapy for patients with a relapse in the central nervous system, but for an isolated bone marrow relapse, no differences in leukemia-free survival were seen between the two groups of patients.

Relationship between patterns of engraftment in peripheral blood and immune reconstitution after allogeneic bone marrow transplantation for (severe) combined immunodeficiency.

We report the outcome of allogeneic bone marrow transplantation (BMT) as treatment for severe combined immunodeficiency disease (SCID) in 31 patients grafted from 1968 until 1992. The patients received a graft from an HLA-identical related (n = 10), an HLA-haplo-identical related (n = 19), or a closely HLA-matched unrelated (n = 2) donor that resulted in the long-term survival of 6 of 10, 9 of 19, and 0 of 2 children, respectively. Major complications included failure of engraftment and early death caused by respiratory failure. The chimerism pattern and immunologic reconstitution were evaluated in 15 children who survived more than 1 year with sustained engraftment. The pattern of engraftment was investigated within flow-sorted peripheral blood (PB) T- and B-lymphoid, natural killer (NK), and myelomonocytic cell populations using the amplification of variable number of tandem repeats by the polymerase chain reaction. The immunologic reconstitution was assessed by various in vitro and in vivo parameters. Although the number of PB T cells and the in vitro T-cell proliferative response was in the lower region of normal in the majority of cases and even subnormal in some, in all cases donor T-cell engraftment and reconstitution of T-cell immunity was observed. Residual host-type T cells (1% to 5%) were detected in eight cases at multiple occasions. All children showed normal serum IgM and IgG subclass levels and produced specific IgG antibodies after vaccination, irrespective of donor B-cell engraftment. However, three HLA haplo-identical graft recipients with host-type B lymphoid and myeloid cells have a persistent selective IgA deficiency. NK cells were either of donor, host, or mixed origin. Donor NK cell engraftment restored defective in vitro NK cell function of the recipient. We conclude that determination of lineage-specific engraftment patterns provides valuable information for the understanding of the immunologic reconstitution after allogeneic BMT for SCID.

Clonal dysregulation of the antibody response to tetanus-toxoid after bone marrow transplantation.

After bone marrow transplantation (BMT), a prolonged dysregulation of humoral immunity can be observed. In the present study, we investigated whether this is reflected in an abnormal production of specific antibodies (Ab) to the T-cell-dependent recall antigen tetanus-toxoid (TT). The study group consisted of children receiving transplants of an unmodified allogeneic graft and of adults receiving either a T-cell-depleted allogeneic or an unmodified autologous BM graft. Findings were compared with those in healthy controls. In pediatric graft recipients, who were routinely revaccinated early after BMT, the Ab response was quantitatively superior to that in adult graft recipients who did not receive early revaccination. In the majority of graft recipients, the time period after vaccination required to reach the peak level of antibodies was prolonged and the number of responding TT-specific B-cell clones was markedly decreased in comparison with controls. In controls, a low frequency of dominant B-cell clones may produce low quantities of homogeneous Ab components (H-Ab) against a heterogeneous background. However, in BM graft recipients, "overshooting" of Ab production by separate B-cell clones was observed, resulting in the development of H-Ab at a relatively high concentration. These abnormalities were present up to 10 years after BMT, irrespective of either the age of the recipient, the modulation of the graft, or the vaccination schedule used. It is hypothesized that the dysregulated Ab production is the consequence of activation of a restricted number of resting memory B cells, present in germinal centers, repopulating gradually after BMT. Our data show that routine revaccination early after BMT improves the humoral immune response. However, because of a clonally dysregulated Ab production, long-lasting qualitative defects may be present even after normalization of Ab titers.

Bone marrow transplantation for autosomal recessive osteopetrosis. A report from the Working Party on Inborn Errors of the European Bone Marrow Transplantation Group.

The outcomes of 69 patients who received allogeneic bone marrow grafts for autosomal recessive osteopetrosis in the period between 1976 and 1994 were analyzed retrospectively. Four patients received bone marrow transplants (BMT) without prior myeloablative conditioning; transient osteoclast function was demonstrated in one of them. Sixty-five patients received myeloablative pretreatment. Recipients of a genotypically human leukocyte antigen (HLA)-identical BMT had an actuarial probability for 5-year survival, with osteoclast function, of 79%; recipients of a phenotypically HLA-identical bone marrow graft from a related or unrelated donor, or one HLA-mismatched graft from a related donor, had an actuarial probability for 5-year survival, with osteoclast function, of 38%; patients who received a graft from an HLA-haplotype mismatched related donor had a probability for 5-year survival of only 13%. The main problems in haplotype-nonidentical BMT were graft failure and BMT-related complications such as sepsis, bleeding, and interstitial pneumonia. Osteoclast function developed in all patients with full engraftment. Recovery of osteoclast function was associated with severe hypercalcemia in 24% of the patients with engraftment, especially those older than 2 years of age. At the time of BMT, severe visual impairment was present in 35% of the patients; of the 15 patients who had visual impairment at the time that a successful BMT was performed, two had improvement after BMT (13%). Within the total group, one patient had neurodegeneration. Engraftment of healthy donor cells had no influence on the progression of that abnormality and BMT thus had no beneficial effect on this phenotype of osteopetrosis. In general, however, early BMT remains the only curative treatment for autosomal recessive osteopetrosis.

Autosomal recessive osteopetrosis: variability of findings at diagnosis and during the natural course.

OBJECTIVE: To determine the variability and the natural course of children suffering from autosomal recessive osteopetrosis to allow optimal counseling and decision making with respect to therapeutic intervention. DESIGN: Retrospective and longitudinal evaluation of clinical symptoms and natural course with emphasis on survival and sensoneurologic and hematologic findings. SETTING: Two large referral-based pediatric bone marrow transplantation units in Europe. PATIENTS: Thirty-three patients with autosomal recessive osteopetrosis admitted to units in Paris and Leiden between 1972 and 1988 were analyzed until last follow-up or the time at which bone marrow transplantation was performed. The great number of patients and unprecedented amount of data make this report one of the single largest clinical studies on autosomal recessive osteopetrosis. MAIN RESULTS: Ocular involvement occurring at a median age of 2 months was the symptom at initial examination in half of the patients. A striking variability between patients was found. Retinal degeneration was present in three patients and associated generalized neurodegeneration was present in two. The probability of survival until the age of 6 years was about 30% for the group as a whole. The cumulative risk of developing visual or hematologic impairment in the first year of life was about 75% and leveled off afterward. Patients with early hematologic impairment, ie, before 3 months of age, especially when combined with early visual impairment, had a very poor prognosis regarding life expectancy. CONCLUSIONS: Autosomal recessive osteopetrosis seems to be a variable disorder with a poor prognosis, especially in children with early visual and hematologic impairment. Allogenic bone marrow transplantation remains the only curative approach.

Ten years after acquiring an HIV-1 infection: a study in a cohort of eleven neonates infected by aliquots from a single plasma donation.

We present data from a 10-year follow-up study of 11 children who had been infected in the neonatal period by small aliquots of plasma from a single donation. Three of the children died within the first 2.5 years of life, 5 other children died between 6.2 and 11 years after infection and 3 are alive at present. The latter children are classified as P1B (asymptomatic), P2A (non-specific findings) and P2B (neurological changes). All infected children showed progressive decline of cellular immunity. Immunoglobulin levels in serum were increased in the majority of children for prolonged periods and homogeneous immunoglobulin components were present. The severity of the disease was related neither to the clinical condition of the infants in the neonatal period nor to the volume of transfused plasma, the interval between freezing and thawing of the plasma, gestational age at birth and age at transfusion. Coinciding infections with other viruses had no impact on disease progression during the follow-up period of 10 years.

Changes in cell and protein content of cerebrospinal fluid in children with acute lymphoblastic leukaemia after allogeneic bone marrow transplantation.

The material from 59 and 134 cerebrospinal fluid (CSF) samples, taken in the week prior to grafting and during the first 100 days after grafting respectively, were examined from 37 children undergoing allogeneic BMT. All CSF samples were obtained from lumbar punctures performed for regular administration of methotrexate (MTX). Prior to bone marrow transplantation (BMT) the increased protein levels and increased cell numbers noted in two children were probably caused by arachnoiditis from MTX administration 5 days earlier. After BMT, cell numbers increased in 54% of children and in 27% of children increased protein levels were found in the CSF. No correlation with clinical findings including neurological findings, infections and prior intrathecal MTX administration was found. The CSF changes observed are probably induced by the conditioning regimen (i.e. cyclophosphamide and total body irradiation). We conclude that the normal ranges for CSF components seen in healthy individuals do not apply in BMT recipients during the first 100 days after grafting.

Immunoglobulin levels and monoclonal gammopathies in children after bone marrow transplantation.

Bone marrow graft recipients suffer profound immunodeficiency during at least 3 months after transplantation. B-cell reconstitution following allogeneic bone marrow transplantation (BMT) in children was studied longitudinally by quantification of Ig (sub)class levels in serum and by investigation of numbers and characteristics of homogeneous Ig components (H-Ig); ie, monoclonal gammopathies (MG). For the latter purpose, a sensitive immunoblotting technique capable of detecting H-Ig of a concentration as low as 0.5 microgram/mL was used. Sera of 40 children grafted for a variety of diseases were investigated and followed up for 5 years. It was found that Ig (sub)classes reached normal levels from 3 months after BMT onward. The sequential increase of the different Ig isotypes was in accordance with that seen in normal ontogeny. This was especially clear following BMT for severe congenital immunodeficiency. H-Ig appeared from as early as 6 weeks after BMT in increasing numbers, beginning within IgM, IgG3, and IgG1, and afterward within other isotypes. After an initial increase of serum Ig levels, "overshooting" occurred accompanied by high frequency of H-Ig. H-Ig were still present at 5 years after BMT, when Ig levels normalized. Our data indicate that B-cell reconstitution after allogeneic BMT recapitulates normal ontogeny but in a clonally dysregulated fashion; that is, with overexpression of some clones and underexpression of others.