The primary immunodeficiencies

Periodic fever syndromes

Human autoinflammatory diseases (except for the periodic fever, adenopathy, pharyngitis, aphthae syndrom) are a heterogeneous group of genetically determined diseases characterized by seemingly unprovoked inflammation, in the absence of autoimmune or infective causes. Tremendous advances in the understanding of these disorders have been seen in the last decade. This article discusses hereditary autoinflammatory syndromes that are associated with recurrent fevers.

Exogenous leptin restores in vitro T cell proliferation and cytokine synthesis in patients with common variable immunodeficiency syndrome

Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by hypogammaglobulinemia. Leptin has been implicated as an antiapoptotic compound as well as a stimulant of the immune response. Leptin administration is capable of reversing the immune deficiency that occurs upon starvation. We investigated a possible role for leptin in CVID; a condition associated with lowered plasma leptin levels. Thirty-eight patients were studied. Addition of leptin to the tissue culture media of PBMC from CVID patients increased the proliferative response of lymphocytes to mitogens and decreased activation-induced apoptosis of these cells. IL-2 and specially IL-4 production also increased significantly upon addition of leptin to the PBMC cultures. Our results suggest that leptin may be involved in some of the cellular defects observed in CVID and indicate a novel therapeutic strategy to improve immune function in these patients.

Déficit immunitaire commun variable avec manifestations auto-immunes : étude de neuf observations ; intérêt d’un immunophénotypage spécifique des lymphocytes B circulants chez sept patients

PURPOSE

Autoimmune manifestations (AIM) are associated to common variable immunodeficiency (CVI) in about 20 to 25% of the cases. This study presents the clinical, biological characteristics and the evolution of nine patients developing CVI and AIM. A peripheral B-cell compartment analysis has been performed in seven cases.

METHOD

This multicenter retrospective study analyses nine patients, six men and three women, within a population of 32 CVI.

RESULTS

The mean age was 27 years at the time of diagnosis of AIM and 30 years at the time of diagnosis of CVI. The diagnosis of AIM preceded the diagnosis of CVI in five cases. Thirteen AIM of different types were observed: autoimmune hemolytic anemia (AHA, 3), immune thrombocytopenic purpura (ITP, 2), Evan's syndrome (2), primary biliary cirrhosis (1), rheumatoid arthritis (1), alopecia totalis (1), myasthenia gravis (1). The peripheral B-cell compartment was investigated in seven patients: five patients with autoimmune cytopenia presented with a diminution of memory B cells (CD27+IgD-) and immature B cells (CD21-) levels; the patient with primary biliary cirrhosis and myasthenia gravis had only a diminution of memory B cells level; the last patient with ITP presented with a normal level of memory B cells. Five among the seven patients with autoimmune cytopenia required a specific treatment using corticosteroids, high dosages of intravenous immunoglobulin, then splenectomy after failure of the medical management, with severe infectious complications in one case.

CONCLUSION

The association of AIM and CVI is not fortuitous. The most common AIM is autoimmune cytopenia. The peripheral B-cell compartment analyses show that a majority of patients have a defect in memory B-cells. Treatment regimens are not standardized and splenectomy increases the risk of infectious complications.

HIV-mediated Expression of Btk in Hematopoietic Stem Cells is not Sufficient to Restore B Cell Function in X-linked Immunodeficient Mice

Mutations of Bruton's tyrosine kinase (Btk), which is critical for B cell development and function, cause X-linked agammaglobulinemia (XLA) in humans and X-linked immunodeficiency (xid) in mice. Although the severity of the clinical phenotype differs between the two species, xid mice are considered useful for evaluating treatment strategies for XLA patients. Hematopoietic stem cells (HSCs; 1 approximately 3 x 10(5))from xid mice were transduced with an HIV vector containing the human Btk (hBtk) gene under the control of the internal murine stem cell virus (MSCV) promoter and injected into 4-week-old xid mice. Thirty weeks later, the copy number of the integrated HIV vector was over 0.2 per cell in both bone marrow and spleen, but serum concentrations of IgM and IgG3 and the antibody response to nitrophenol (NP)-Ficoll challenge were not restored. The number of differentiated B cells (IgM(low)IgD(high)) was increased, while the peritoneal B1 cell count remained low. These results indicate that HIV-mediated expression of hBtk in bone marrow stem cells partially promotes B cell development, but is not sufficient for the restoration of B cell function in xid mice.

Bruton's tyrosine kinase is essential for human B cell tolerance

Most polyreactive and antinuclear antibodies are removed from the human antibody repertoire during B cell development. To elucidate how B cell receptor (BCR) signaling may regulate human B cell tolerance, we tested the specificity of recombinant antibodies from single peripheral B cells isolated from patients suffering from X-linked agammaglobulinemia (XLA). These patients carry mutations in the Bruton's tyrosine kinase (BTK) gene that encode an essential BCR signaling component. We find that in the absence of Btk, peripheral B cells show a distinct antibody repertoire consistent with extensive secondary V(D)J recombination. Nevertheless, XLA B cells are enriched in autoreactive clones. Our results demonstrate that Btk is essential in regulating thresholds for human B cell tolerance.

[Common variable immunodeficiency and celiac disease]

Variable immunodeficiency is frequently associated with subtotal villous atrophy, unchanged by gluten free diet. We report two cases of common variable immunodeficiency associated with chronic symptoms of malabsorption due to total villous atrophy. Symptoms of malabsorption disappeared and histological abnormalities improved after a gluten free diet. The association between celiac disease and common variable immunodeficiency should not be considered as fortuitous. Clinicians should be aware of this association and of the low sensitivity of serologic testing in this setting.

Natural antibodies sustain differentiation and maturation of human dendritic cells

The differentiation and maturation of dendritic cells (DCs) is governed by various signals in the microenvironment. Monocytes and DCs circulate in peripheral blood, which contains high levels of natural antibodies (NAbs). NAbs are germ-line-encoded and occur in the absence of deliberate immunization or microbial aggression. To assess the importance of NAbs in the milieu on DC development, we examined the status of DCs in patients with X-linked agammaglobulinemia, a disease characterized by paucity of B cells and circulating antibodies. We demonstrate that the in vitro differentiation of DCs is severely impaired in these patients, at least in part because of low levels of circulating NAbs. We identified NAbs reactive with the CD40 molecule as an important component that participates in the development of DCs. CD40-reactive NAbs restored normal phenotypes of DCs in patients. The maturation process induced by CD40-reactive NAbs was accompanied by an increased IL-10 and decreased IL-12 production. The transcription factor analysis revealed distinct signaling pathways operated by CD40-reactive NAbs compared to those by CD40 ligand. These results suggest that B cells promote bystander DC development through NAbs and the interaction between NAbs and DCs may play a role in steady-state migration of DCs.

Acute respiratory failure in a patient with sarcoidosis and immunodeficiency--an unusual presentation and a complicated course

Pulmonary sarcoidosis is usually a chronic, insidious disease resulting from granuloma formation in the lung parenchyma. The epithelioid non-caseating granulomata of sarcoidosis are the result of a T-helper1-mediated immune reaction to an unknown self or foreign antigen. We describe the case of a patient with sarcoidosis and a coexistent common variable immunodeficiency who presented with rapidly progressive respiratory failure. This unusual presentation was followed by a complicated course with recurrent pneumoccocal infections, which could be explained by the coexistence of common variable immunodeficiency. Physicians should be alert to the possibility of sarcoidosis even when the clinical presentation is of acute respiratory distress syndrome (ARDS) since early treatment with steroids can be lifesaving. The detection of accompanying hypogammaglobulinemia is also crucial, as treatment with intravenous immunoglobulins (IVIG) together with steroids can improve the patient's outcome.

Common variable immunodeficiency patient classification based on impaired B cell memory differentiation correlates with clinical aspects

Common variable immunodeficiency (CVID) is a very heterogeneous syndrome defined by impaired immunoglobulin production. The functional classification of CVID patients on the basis of in vitro immunoglobulin production is time consuming and has never shown any predictive value. We propose a classification based on the quantitative repartition of naive/memory B cells according to the dual expression of IgD and CD27. Fifty-seven patients were categorized into three groups: Group MB2 (11 patients, 19%) with normal memory B cells; Group MB1 (19 patients, 33%) with defective switched memory (IgD-CD27+) but normal nonswitched memory B cells (IgD+CD27+); Group MB0 (27 patients, 47%) with almost no memory B cells. In addition, a downexpression of activation markers (CD25, CD21, CD80, CD86) on B cells characterized the group MB1 patients and was associated with an upexpression of activation markers (HLA-DR, CD95, CD57) on T cells. This classification correlates with some clinical aspects showing a higher prevalence of splenomegaly (16/27, 59%), lymphoid proliferation (13/27, 48%) and granulomatous disease (12/27, 44%) in group MB0. Splenomegaly was also frequent in group MB1 (8/19, 42%). In contrast, autoimmunity was observed with similar prevalence in all three groups. Moreover, by analyzing B cell phenotype, immunoglobulin transcript expression, and somatic mutations, we propose different putative mechanisms responsible for impaired B cell activation and memory differentiation in this syndrome.

Malignant solid tumors associated with congenital immunodeficiency disorders

This objective of this study was to evaluate patients with immunodeficiency syndromes who had developed malignant solid tumors and to examine survival rates and prognosis with respect to type of immunodeficiency disease. Twenty-two patients who were diagnosed with malignant solid tumors and immunodeficiency syndromes between January 1972 and February 2003 were analyzed retrospectively. There were 12 (55%) patients with non-Hodgkin lymphoma, 8 (37%) with Hodgkin disease, 1 (5%) with mucinous adenocarcinoma of the colon, and 1 (5%) with brain stem glioma. Fifteen (68%) patients had ataxia-telangiectasia, 3 (14%) had common variable immunodeficiency disease, 2 (9%) had Bloom syndrome, 1 (5%) had combined immunodeficiency, and 1 (5%) had selective immunoglobulin A deficiency. Out of the 15 patients with ataxia-telangiectasia 9 patients had non-Hodgkin lymphoma, 5 had Hodgkin disease, and 1 had brain stem glioma. Two patients with common variable immunodeficiency disease had non-Hodgkin lymphoma and 1 had Hodgkin disease. One of the patients with Bloom syndrome had Hodgkin disease and 1 had colon carcinoma. The overall survival for the whole group was 24%. Overall survival rates in non-Hodgkin lymphoma, Hodgkin disease, colon carcinoma, and brain stem glioma were 17, 44, 0, and 0% (p =.25), respectively. Overall survival in ataxia-telangiectasia patients was 20%. In this series, most of the patients had ataxia-telangiectasia (68%). The survival rates of the malignant diseases were very poor in immunodeficiency. Overall survival in non-Hodgkin lymphoma patients was relatively worse than Hodgkin disease patients.

Autoimmune manifestations in common variable immunodeficiency

Common variable immunodeficiency (CVID) is a disorder characterized by decreased serum immunoglobulin concentrations and increased incidence of recurrent infections. Interestingly 20-25% of patients with CVID develop clinical features suggestive of an autoimmune disease. Although this association is well established, the immunodeficiency background of CVID patients manifesting autoimmune disorders is often overlooked. This study describes three CVID patients displaying a variety of autoimmune manifestations. The pathophysiologic mechanisms of autoimmunity in CVID are also reviewed.

[Feasibility of administering Tegeline at home. Retrospective study of efficacy, safety and tolerance]

OBJECTIVE

To demonstrate the feasibility of administration Tegeline at home from a point of view of efficacy, safety, tolerance, to validate the pertinence of the selection and the training of patients who could benefit from this type of administration and to assess the long term efficacy and safety.

METHOD

This retrospective study was conducted in patients exhibiting primary immune deficiency and formerly treated with intravenous immunoglobulins at least six months in hospital settings, trained by the centre for the training of children in the home (Centre de formation au traitement à domicile de l'enfant--CFTDE) and having received at least one administration of Tegeline at home from January 1st 2000. Tegeline contains a mean of 97.6% of whole IgG (58.8% of IgG1, 34.1% of IgG2, 5.4% of IgG3 and 1.7% of IgG4).

RESULTS

Two hundred and eighteen follow-up sheets were completed by 13 patients in whom all the eligibility criteria were fulfilled. The total number of infusions per patient ranged from 4 to 41. No difficulty in administration was reported in 10 patients, difficulties in placing the needle were encountered in 3 other patients and motivating their return to the hospital for treatment (after 6 and 10 months) in 2 cases. The infusion flow rate was usually of 2 to 3 ml/kg/h. During the follow-up period, no episode of infection was noted in 5 patients and 8 presented infections that were treated with antibiotics. Regarding safety, the security 'kits' (corticosteroids, adrenalin) that were supplied to each patient were never used. Over time, the median duration of the infusions at home was of 5 years and 6 months.

CONCLUSION

In trained and selected patients, this study demonstrated the efficacy, safety and tolerance to the administration of Tegeline at home.

Failure to clear persistent vaccine-derived neurovirulent poliovirus infection in an immunodeficient man

BACKGROUND

Individuals who chronically excrete neurovirulent poliovirus of vaccine-origin are of considerable concern to the Global Polio Eradication programme. Chronic infection with such polioviruses is a recognised complication of hypogammaglobulinaemia.

METHODS

We did a series of in-vitro and in-vivo therapeutic studies, with a view to clearing persistent neurovirulent poliovirus infection in an individual with common variable immunodeficiency, using oral immunoglobulin, breast milk (as a source of secretory IgA), ribavirin, and the anti-picornaviral agent pleconaril. We undertook viral quantitation, antibody neutralisation and drug susceptibility assays, and viral gene sequencing.

FINDINGS

Long-term asymptomatic excretion of vaccine-derived neurovirulent poliovirus 2 was identified in this hypogammaglobulinaemic man, and was estimated to have persisted for up to 22 years. Despite demonstrable in-vitro neutralising activity of immunoglobulin and breast milk, and in-vitro antiviral activity of ribavirin, no treatment was successful at clearing the virus, although in one trial breast milk significantly reduced excretion levels temporarily. During the course of study, the virus developed reduced susceptibility to pleconaril, precluding the in-vivo use of this drug. Sequence analysis revealed the emergence of a methionine to leucine mutation adjacent to the likely binding site of pleconaril in these isolates.

INTERPRETATION

Chronic vaccine-associated poliovirus infection in hypogammaglobulinaemia is a difficult condition to treat. It represents a risk to the strategy to discontinue polio vaccination once global eradication has been achieved.

Simultaneous Nonparotid Cranial Mucosa-Associated Lymphoid Tissue Lymphoma and Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is a condition characterized by low levels of immunoglobulin (Ig) G and either IgA or IgM in the presence of recurrent infections. This disorder is associated with an increased risk of malignancy. Mucosa-associated lymphoid tissue (MALT) lymphoma is a recently recognized form of non-Hodgkin's lymphoma that is not often present in the head. MALT lymphoma in patients with CVID is rare, and until now, it has not been reported in a cranial location outside of the parotid gland. We report the cases of 2 patients who had CVID and cranial MALT lymphoma outside of the parotid gland, and we describe their successful treatment with chemotherapy.

Species comparison of anatomical and functional immune system development

The components of the immune system have not been traditionally emphasized as potential target organs in standard developmental and reproductive toxicity (DART) protocols. A number of workshops have been organized in recent years to examine scientific questions that underlie developmental immunotoxicity tests, and the interpretation of results as they relate to human risk assessment. A key question that must be addressed is to determine the most appropriate species and strains to model the developing human immune system. The objective of this review is to compare the anatomical and functional development of the immune system in several species important to either preclinical studies for drug development or safety assessments for chemicals, with what is known in humans. The development of the immune system in humans will be compared to what is known in mice, rats, dogs and nonhuman primates.

Thymopoiesis and T cell development in common gamma chain-deficient dogs

Our laboratory has identified an X-linked severe combined immunodeficiency (XSCID) in dogs that is the result of mutations in the common gamma chain (gammac) subunit of the interleukin-2 (IL-2), IL-4, IL-7, IL-9, IL-15, and IL-21 receptors. Canine XSCID, unlike genetically engineered gammac-deficient mice, has a clinical and immunologic phenotype virtually identical to human XSCID, suggesting species-specific differences exist in the role of the gammac and its associated cytokines in mice in comparison to their role in humans and dogs. This review compares and contrasts thymopoiesis and postnatal T cell development in gammac-deficient (XSCID) dogs raised in a conventional environment, with gammac-deficient dogs raised in a gnotobiotic environment. Therapy to accelerate T cell regeneration following hematopoietic stem cell transplantation or gene therapy is also discussed.

Identifying undiagnosed primary immunodeficiency diseases in minority subjects by using computer sorting of diagnosis codes

BACKGROUND

Primary immunodeficiency diseases occur in all populations, but these diagnoses are rarely made in minority subjects in the United States.

OBJECTIVE

We sought to develop and validate a method to identify patients without diagnoses but with immunodeficiency in an urban hospital with a substantial minority patient population.

METHODS

We developed a scoring algorithm on the basis of International Classification of Disease, Ninth Revision (ICD-9) codes to identify all hospitalized patients age 60 years or less who had been given a diagnosis of 2 or more of 174 ICD-9-coded complications associated with immunodeficiency. Codes were weighted for severity and expressed as a sum for all admissions between October 1, 1995, and December 31, 2002. Patients with, for example, cancer or HIV or those after transplantation or major surgery were excluded. Demographic features of subjects with aggregated ICD-9 codes suggestive of immunodeficiency were compared with those of other inpatients; 59 computer-selected subjects were then tested for immune defects.

RESULTS

The computer-identified group contained 533 patients (0.4% of all inpatients), who had been hospitalized 2683 times. The median age was 6.6 years. Sixty-five percent were African American or Hispanic, and 61% were insured by Medicaid, which is significantly more than other inpatients younger than 60 years of age (median age, 32.6 years; 37% minority, 27% insured by Medicaid; P<.0001). Primary immunodeficiency was found in 17 (29%) of the 59 subjects tested. Thirteen other patients had secondary immune defects, and 86% of immunodeficient subjects were Hispanic or African American.

CONCLUSIONS

An ICD-9-based scoring algorithm identifies patients demographically different from other hospitalized subjects who have multiple illnesses suggestive of immunodeficiency. This group contains undiagnosed minority patients with immunodeficiency.

Common Variable Immunodeficiency and Breast Cancer

We describe two women with early onset breast cancer (at ages 31 and 38) who were found to have common variable immunodeficiency (CVID). Both women had a history of frequent and unusual bacterial infections. The incidence of breast cancer in young women and of CVID are both low, and the coincident diagnosis in two patients from a relatively small population base suggests the possibility of a pathophysiologic or causal relationship.

Granulomas in common variable immunodeficiency: A diagnostic dilemma

A 60-year-old man with common variable immunodeficiency presented with a 7-year history of violaceous plaques and papules on the thighs, arms and trunk. In the preceding 2 years he had developed new lesions on both hands. He had been previously diagnosed with sarcoidosis on the basis of skin and visceral histology, but subsequent opinion was that these were sarcoid-like granulomas rather than being representative of true sarcoidosis. Biopsy of the hand lesions showed necrotizing granulomas, and a single acid-fast bacillus (AFB) was identified on Wade-Fite stain. Subsequent repeat tissue biopsies for histology, culture and polymerase chain reaction testing failed to confirm the presence of mycobacterial organisms and it was felt that the organism was a contaminant introduced during tissue processing. The hand lesions responded well to intralesional injections of triamcinolone acetonide 10 mg/mL and oral tetracycline 500 mg b.d. was later introduced with a good clinical response. The diagnostic dilemma of finding granulomatous inflammation in a patient with common variable immunodeficiency, and the significance of a single AFB on histology are discussed. The treatment of sarcoid-like granulomas with tetracycline therapy is also commented on.

Nonmyeloablative hematopoietic stem cell transplant for X-linked hyper-immunoglobulin m syndrome with cholangiopathy

OBJECTIVE

X-linked hyper-immunoglobulin M (X-HIM) syndrome is a rare genetic immunodeficiency syndrome caused by mutations in the gene encoding CD40 ligand (CD40L, CD154). Allogeneic hematopoietic stem cell transplantation (HSCT) offers the prospect of immune reconstitution in X-HIM syndrome. Standard HSCT using high-dose chemoradiotherapy can be followed by serious hepatic problems, including veno-occlusive disease, graft-versus-host disease, and/or drug-induced hepatotoxicity. In patients whose liver function is compromised before HSCT, such as in X-HIM syndrome caused by cholangiopathy and hepatitis related to opportunistic infections, there is a higher likelihood of hepatotoxicity. We explored nonmyeloablative HSCT in 2 patients with X-HIM syndrome. Nonmyeloablative HSCT without liver transplant for X-HIM syndrome, to our knowledge, has not been described previously.

METHODS

Two children with X-HIM syndrome and persistent infections had documented cholangiopathy on liver biopsy. Both children underwent nonmyeloablative HSCT from HLA-matched siblings with fludarabine, busulfan, and anti-thymocyte globulin as their preparative regimen. Graft-versus-host disease prophylaxis consisted of cyclosporine.

RESULTS

Both children are >2 years after their HSCT. One remains a mixed chimera, and the other shows 100% donor chimerism. Both children are now free of infections and are no longer dependent on intravenous gammaglobulin. Both show response to immunizations. Both have had resolution of their cholangiopathy.

CONCLUSIONS

Nonmyeloablative HSCT from HLA-matched siblings can offer immune reconstitution without hepatotoxicity in patients with X-HIM syndrome and preexisting cholangiopathy. Even with stable mixed chimerism after allogeneic HSCT, patients may be able to enjoy a normal phenotype. Nonmyeloablative HSCT warrants additional study in X-HIM syndrome.

Current applications of flow cytometry in the diagnosis of primary immunodeficiency diseases

CONTEXT

To review the applications of flow cytometry in the diagnosis and management of primary immunodeficiency disease.

DATA SOURCES

Articles describing the use of flow cytometry in the diagnosis of several primary immunodeficiency diseases were obtained through the National Library of Medicine database.

STUDY SELECTION

Publications that described novel and known applications of flow cytometry in primary immunodeficiency disease were selected. Review articles were included. Articles describing the different immunodeficiency diseases and methods of diagnosis were also selected.

DATA EXTRACTION

Approximately 100 data sources were analyzed, and those with the most relevant information were selected.

DATA SYNTHESIS

The diagnosis of many primary immunodeficiency diseases requires the use of several laboratory tests. Flow cytometry has become an important part of the workup of individuals suspected to have such a disorder. Knowledge of the pathogenesis of many of these diseases continues to increase, hence we acquire a better understanding of the laboratory tests that may be helpful in diagnosis.

CONCLUSIONS

Flow cytometry is applicable in the initial workup and subsequent management of several primary immunodeficiency diseases. As our understanding of the pathogenesis and management of these diseases increases, the use of many of these assays may become routine in hospitals.

Cutaneous sarcoid-like granulomas in a patient with X-linked hyper-IgM syndrome

We describe a 5-year-old boy with red-pink, firm, nodular lesions, with central resolution and prominent borders, localized to the face, backs of the hands, extensor surfaces of the arms and legs, and the buttocks. He also had recurrent bacterial respiratory infections. Quantitative immunoglobulin levels revealed hypogammaglobulinemia and increased IgM levels. Histopathologic examination of a nodular lesion revealed perivascular and periadnexal granulomas composed of epithelioid cells surrounded by a mantle of lymphocytes; three cultures for fungi and acid-fast bacilli were negative. Clinical, histopathologic, and immunologic studies supported a diagnosis of hyper-IgM (HIM) syndrome. The boy was treated with pulsed-dose antibiotics and intravenous gamma globulin every 3 weeks, with improvement of clinical symptoms. Skin lesions were treated with topical corticosteroids, with immediate recurrence upon cessation of therapy. To the best of our knowledge, this is the first description of cutaneous granulomas in HIM syndrome.

Susceptibility to fungal infections of nails in patients with primary antibody deficiency

Primary antibody deficiencies are rare diseases, which require early treatment with intravenous immunoglobulins to prevent fatal infections. The cell mediated immunity in patients with those immunodeficiencies remains unimpaired and usually they do not develop fungal infections. The aim of the study was to determine the susceptibility to fungal infections of nails in children with X-linked agammaglobulinaemia (XLA) and common variable immunodeficiency (CVID). Nail plate fragments collected from five patients with XLA and five with CVID were experimentally infected with a Candida albicans and Trichophyton mentagrophytes strains. The same procedures were carried out with the nails from a control group of 10 healthy volunteers. The intensity of the infection was evaluated on the basis of hyphae ingrown into the nail fragments. The main finding of the study was the increased susceptibility of antibody deficient patients to experimental nail infection with C. albicans and T. mentagrophytes.

Bruton's tyrosine kinase defect in dendritic cells from X-linked agammaglobulinaemia patients does not influence their differentiation, maturation and antigen-presenting cell function

X-linked agammaglobulinaemia (XLA) is a primary immunodeficiency disease characterized by very low levels or even absence of circulating antibodies. The immunological defect is caused by deletions or mutations of Bruton's tyrosine kinase gene (Btk), whose product is critically involved in the maturation of pre-B lymphocytes into mature B cells. Btk is expressed not only in B lymphocytes but also in cells of the myeloid lineage, including dendritic cells (DC). These cells are professional antigen presenting cells (APC) that play a fundamental role in the induction and regulation of T-cell responses. In this study, we analysed differentiation, maturation, and antigen-presenting function of DC derived from XLA patients (XLA-DC) as compared to DC from age-matched healthy subjects (healthy-DC). We found that XLA-DC normally differentiate from monocyte precursors and mature in response to lipopolysaccharide (LPS) as assessed by de novo expression of CD83, up-regulation of MHC class II, B7.1 and B7.2 molecules as well as interleukin (IL)-12 and IL-10 production. In addition, we demonstrated that LPS stimulated XLA-DC acquire the ability to prime naïve T cells and to polarize them toward a Th1 phenotype, as observed in DC from healthy donors stimulated in the same conditions. In conclusion, these data indicate that Btk defect is not involved in DC differentiation and maturation, and that XLA-DC can act as fully competent antigen presenting cells in T cell-mediated immune responses.

Efficacy, tolerability, safety and pharmacokinetics of a nanofiltered intravenous immunoglobulin: studies in patients with immune thrombocytopenic purpura and primary immunodeficiencies

BACKGROUND AND OBJECTIVES

A nanofiltration step with the capacity to reduce blood-borne pathogens was introduced into the manufacturing process of intravenous immunoglobulin (IVIG). In order to demonstrate the efficacy, safety and pharmacokinetics of the modified product, we conducted Phase II/III studies comparing the nanofiltered IVIG (IVIG-N) with its parent product, Sandoglobulin, in patients with chronic immune thrombocytopenic purpura (ITP) and primary immunodeficiencies (PID).

MATERIALS AND METHODS

Patients with ITP (n = 27) with platelet counts of < 20 x 10(9)/l were treated with Sandoglobulin or IVIG-N infusions at a dose of 0.4 g/kg body weight on five consecutive days. The primary efficacy end-point was the number of patients with an increase in platelet counts to > 50 x 10(9)/l. Secondary end-points were time to and duration of response, and regression of bleeding. Patients with PID (n = 36) were treated for 6 months with Sandoglobulin or IVIG-N at doses of 0.2-0.8 g/kg, infused at 3- or 4-week intervals. The primary end-point was the number of days absent from school/work. Secondary end-points were hospitalization, use of antibiotics and feeling of well-being. In both studies, tolerability was assessed by recording of adverse events and laboratory determinations. Viral safety was ascertained by serology supplemented with nucleic acid detection methods. Pharmacokinetics were analysed in patients with PID using serum concentration-time data for immunoglobulin G (IgG), and IgG antibodies to hepatitis B surface antigen (anti-HBsAg).

RESULTS

In the ITP study, the primary end-point was met by 12/16 patients on IVIG-N and by 10/10 patients on Sandoglobulin (P = 0.123). A shift towards lesser bleeding intensity was seen in both groups. In the PID study, seven of 18 patients on IVIG-N and six of 16 patients on Sandoglobulin missed days at work/school, with monthly mean absences of 0.4 and 0.5 days (P = 0.805). The feeling of well-being was comparable in both groups. In the ITP study, adverse events with a causal relationship to medication were suspected in six patients on IVIG-N and in seven on Sandoglobulin. In the PID study, three patients on IVIG-N and two on Sandoglobulin experienced possible drug-related adverse events. In both studies, serological and polymerase chain reaction (PCR) tests gave evidence for virus safety. Pharmacokinetics showed constant peak and trough serum IgG levels in all patients, indicating almost steady-state conditions for both formulations. The overall half-life (t1/2) for total IgG was 33 +/- 17 days in the IVIG-N arm and 25 +/- 16 days in the Sandoglobulin arm; for anti-HBsAg t1/2, values were 17 +/- 7 and 17 +/- 9 days, respectively.

CONCLUSIONS

IVIG-N is efficacious, well tolerated and safe in patients with ITP and PID. Its pharmacokinetic properties were comparable to those of Sandoglobulin.

Successful unrelated cord blood transplantation in two children with severe combined immunodeficiency syndrome

We describe the successful unrelated cord blood transplantation in two patients affected by a Zap-70 deficiency and an Omenn-like syndrome, respectively. The patients were hospitalised for recurrent infections at the age of 13 and 2 months, respectively. An unrelated cord blood unit was found for each. The conditioning regimen was cyclophosphamide, busulfan and antithymocyte globulin. The total number of infused cells was 15.1 x 10(7)/kg and 17 x 10(7)/kg, respectively. Neutrophil engraftment was achieved on days +15 and +23, and platelet count >50 x 10(9)/l was achieved on days +21 and +52, respectively. One patient presented acute Graft-versus-host disease (GVHD) grade I and the other grade III. Chimerism was mixed and full donor. Normal lymphoproliferative response to mitogens and alloantigens was detectable at 6 months for both. No chronic GVHD was observed in either. The patients are alive and well at 53 and 15 months after transplantation. In conclusion, umbilical cord blood represents a valid alternative source of haemopoietic stem cells.

The rat as a model in developmental immunotoxicology

Evidence is presented to demonstrate that the rat is a sensitive rodent species for developmental immunotoxicity testing of chemicals. A battery of immune function assays was performed in adult rats, which were exposed perinatally (i.e., during gestational, lactational, and/or juvenile development) to three different classes of environmental chemicals. The chemicals employed were the following: the organotins di-n-octyltindichloride (DOTC) and tributyltin oxide (TBTO); the polyhalogenated aromatic hydrocarbon 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD); and the organochlorine pesticides methoxychlor (MXC) and heptachlor (HEP). Suppression of immune function was observed in adult rats exposed to each of these chemicals during immune system development. The duration of immune function suppression in the rats so exposed ranged from three weeks (i.e., DOTC and MXC) to 19 months (i.e., TCDD) after the last exposure to the chemical.

Obsessive-compulsive disorder and immunocompetence

OBJECTIVE

A postinfectious, autoimmune response may be associated with the development of pediatric obsessive-compulsive disorder (OCD). According to this model, antistreptococcal antibodies cross-react with basal ganglia neurons following streptococcus infection. This autoimmune reaction disrupts a basal ganglia-thalamocortical circuit and generates obsessive-compulsive symptoms. One implication of this model is that prolonged immunologic stress may be a risk factor for OCD. That is, immunologic stress may compromise the blood-brain barrier and permit the influx of antistriatal antibodies into the central nervous system. This article explores one part of this putative relationship by investigating whether adult OCD patients, compared to members of other psychiatric groups, demonstrate a higher incidence of recurrent infections and other conditions suggestive of compromised immune function.

METHOD

To test this hypothesis, we conducted a medical records review of 100 consecutive patients evaluated at a private psychiatric clinic specializing in the treatment of anxiety disorders. Sixty-five patients met diagnostic criteria for an Axis-I syndrome. Primary diagnoses included OCD, posttraumatic stress disorder, social anxiety disorder, generalized anxiety disorder, panic disorder with agoraphobia, and dysthymic disorder. Each medical record was reviewed for the presence of target syndromes or presenting symptoms suggestive of compromised immune function.

RESULTS

Chart review revealed an increased rate of immune-related symptoms and syndromes among OCD patients in comparison to other anxiety and mood disorder groups. Groups did not differ significantly in the incidence of non-immune symptoms and syndromes.

CONCLUSION

Adult OCD patients appear to have an increased rate of immune-related diseases above and beyond that seen in other psychiatric disorders.

A case of common variable immunodeficiency presenting with furunculosis

Common variable immunodeficiency (CVID) is the most prevalent of the primary immunodeficiencies, and is characterised by low IgG and IgA, and sometimes IgM. There is some evidence of genetic susceptibility, with 20% of patients having a dominantly inherited disorder with variable expression. It is a heterogeneous disorder with protean manifestations, and as a result diagnosis is often delayed until the second or third decade, with resultant irreversible organ damage, in particular bronchiectasis. Effective treatment is available with regular 3-4-weekly infusions of immunoglobulin. The mechanism of the immunodeficiency has not yet been fully elucidated. The majority of patients present with recurrent sinopulmonary infection, however, this is a multisystem disorder and thus presents to physicians in diverse specialties including dermatology. Other clinical features of the disorder include gastrointestinal problems, granulomatous inflammation, cutaneous features, unusual presentations of enteroviral and mycoplasma infection, an increased incidence of autoimmunity, and a predisposition to lymphoma and stomach cancer. Therefore a knowledge of the disorder and appropriate suspicion by all clinicians of the possibility of such rare problems and a consequent low threshold for performing relevant investigations is imperative in allowing early recognition and instituting effective treatment. We describe a case of CVID identified when the patient developed widespread skin infection, fever and malaise. This case is an important example of a possible presentation of CVID within the dermatology clinic and demonstrates that maintaining a high level of clinical suspicion is essential for the diagnosis of the rare primary immunodeficiencies.

Immune consequences of mutations in the human common gamma-chain gene

A mutation (c.878T>A) in the common gamma chain (gamma(c)) causes an X-linked combined immunodeficiency (XCID) in a large kindred of British origin. In the disease, gamma(c) is expressed, but its binding to Jak3 is reduced. The immune deficiencies and clinical course were less marked in toddlers and school age children with XCID(L293Q) than in severe combined immunodeficiency (SCID). However, affected newborns were profoundly deficient in thymic size and T cells. In some affected infants, thymic size and numbers of T cells gradually increased during the first year. Their clinical course was relatively benign. In affected infants of one lineage, the number of blood T cells failed to increase substantially. They succumbed to opportunistic infections. T cell deficiencies in XCID(L293Q) progressively worsened during adolescence. Decreased thymic function, failure to rescue T cells from apoptosis, and replication senescence were possible causes. Blood T cells with the phenotype CD45RA(+)CD62L(+) (unstimulated T cells) were most depressed. CD4(+) T cells were also deficient in a specific marker of recent thymic emigrants, episomal DNA deletion circles created during TcR gene rearrangements. Apoptosis of T cells was increased, but neither apoptosis nor cell death was age-related. In contrast, telomere shortening in T cells increased with age. Unlike murine gamma(c) gene deletions, gamma delta T cells were prominent in affected adolescents and young adults. Furthermore, T cells with a V delta 2/V gamma 9 specificity declined with age and were replaced in the oldest male with a V delta 1 specificity. Thus, the mutation provides many insights concerning the role of gamma(c) in the biology of T cells.

A founder mutation in Artemis, an SNM1-like protein, causes SCID in Athabascan-speaking Native Americans

Athabascan SCID (SCIDA) is an autosomal recessive disorder found among Athabascan-speaking Native Americans and is manifested by the absence of both T and B cells (T(-)B(-)NK(+) SCID). We previously mapped the SCIDA gene to a 6.5-cM interval on chromosome 10p. SCIDA fibroblasts were found to have defective coding joint and reduced, but precise signal joint formation during V(D)J recombination. After excluding potential candidate genes, we conducted a combined positional candidate and positional cloning approach leading to the identification of nine novel transcripts in the refined SCIDA region. One of the transcripts showed significant homology with the mouse and yeast SNM1/PSO(2) and was recently reported (Artemis) to be responsible for another T(-)B(-)NK(+) SCID condition (radiation sensitive SCID) in 13 patients of primarily European origin. In our evaluation of this gene, we have identified a unique nonsense mutation in 21 SCIDA patients that is closely correlated to the founder haplotypes that we had previously identified. This nonsense founder mutation results in the truncation of the deduced protein product. The wild-type construct of the primary transcript can effectively complement the defective coding joint and reduced signal joint formation in SCIDA fibroblasts. The above results indicate that this SNM1-like gene (Artemis) is the gene responsible for SCIDA. We also discovered three additional alternative exons and detected at least six alternatively spliced SCIDA variants (SCIDA-V1, 2, 3, 4, 5, and 6) coexisting with the primary transcript in trace amounts. Finally, we found that the SCIDA primary transcript (Artemis) encodes a nuclear protein.

Neutropenia associated with primary immunodeficiency syndromes

The primary immunodeficiency diseases are a heterogeneous group of more than 75 disorders characterized by intrinsic defects in the functions of the immune system. Many are associated with abnormalities of hematopoiesis as well. This article will review those primary immunodeficiency syndromes in which neutropenia is a prominent finding, including X-linked agammaglobulinemia (XLA), hyper IgM syndrome, common variable immunodeficiency (CVID), IgA deficiency, cartilage-hair hypoplasia (CHH), and reticular dysgenesis, with regards to pathophysiologic findings and treatment.

[Gastrointestinal alterations in a female patient with common variable immunodeficiency]

We present the case of a 33-year-old woman who complained of intermittent diarrhea over the previous 8 years and who was diagnosed with common variable immunodeficiency. The woman presented antral atrophic gastritis, partial atrophy of the duodenal villi, nodular lymphoid hyperplasia of the small intestine and lymphocytic colitis. We also review the literature.

Herpes simplex virus lymphadenitis: case report and review of the literature

Localized or regional necrotizing lymphadenitis is an extremely uncommon manifestation of herpes simplex virus (HSV) infection. We report a case of necrotizing HSV lymphadenitis in a patient with both common variable immunodeficiency and natural killer cell deficiency and review the literature on this unusual complication of HSV infection.

Linking cellular activation to cytoskeletal reorganization: Wiskott-Aldrich syndrome as a model

The Wiskott-Aldrich syndrome is an inherited X-linked disorder characterized by immune deficiency, eczema, and thrombocytopenia with small platelets. The mutated protein, Wiskott-Aldrich syndrome protein, is an activator of actin cytoskeletal reorganization in hematopoietic cells. Members of the Wiskott-Aldrich syndrome protein family are being shown to be key integrators of cell signalling and cytoskeletal organization in many eukaryotic cell types. This review focuses on recent discoveries that reveal in increasing detail how Wiskott-Aldrich syndrome protein and its related proteins operate.

Blood gammadelta T cells and gammadelta TCR V gene specificities in a single missense mutation (L-->Q271) in the common gamma chain gene

The numbers of blood CD4+, CD8+, and CD4-CD8- T cells bearing alphabeta T-cell receptor (TCR) or gammadelta TCR molecules in males with a single missense mutation (L-->Q271) in the common gamma chain gene (gamma(c)) were investigated by flow cytometry. Virtually all XCIDL-->Q271 blood T cells that were CD4+ or CD8+ displayed alphabeta TCR but no gammadelta TCR. In contrast, CD4-CD8- T cells from affected males usually displayed gammadelta TCR, but no alphabeta TCR. The gammadelta TCR specificities were also studied. Except for the oldest subject, there was a direct relationship between blood CD3+ T cells that displayed gammadelta TCR and Vgamma9 and Vdelta2a specificities. Relative frequencies of CD3+ blood T cells that were Vgamma9+ or Vdelta2a+ were inversely related to age. In the oldest patient, the only detected gammadelta TCR specificity was Vdelta1. Thus, in contrast to mice with no gamma(c), XCIDL-Q271 blood T cells that bear gammadelta TCR with Vgamma9/Vdelta2a specificities develop but then decline in late childhood and thereafter. TCR with the Vdelta1 specificity then appear in older survivors with XCIDL-->Q271.

Genesis of progressive T-cell deficiency owing to a single missense mutation in the common gamma chain gene

Patients with a moderate X-linked combined immunodeficiency (XCID) owing to a single missense mutation in the common gamma chain (gammac) gene (L-->Q271) were found to have a progressive T-cell deficiency. Blood T cells from four older subjects with XCIDL-->Q271 were studied to ascertain the basis of that progression. Few CD4+ T cells displayed the phenotype (CD45RA+ CD62L+) or deletion circles from T-cell receptor (TCR) Vbeta-gene rearrangements found in recent thymic emigrants. These deficiencies were more severe in older males with XCIDL-->Q271. Relative frequencies of fresh CD4+ and CD8+ T cells that bound annexin V, an early indicator of programmed cell death, or propidium iodide, an indicator of cell necrosis, were greater in XCIDL-->Q271 T cells than in normal fresh T cells. The binding of annexin V and propidium iodide to XCIDL-Q271 T cells increased marginally after stimulation with anti-CD3, but binding by fresh or stimulated XCIDL-Q271 T cells exceeded that found in normal stimulated T cells. Also, telomeres from XCIDL-->Q271 CD4+ T cells were shortened in these patients compared to normal young adults. It therefore appears that the thymus is dysfunctional and that mature T cells are not effectively rescued from apoptosis or replication senescence via gamma-mediated pathways in XCIDL-->Q271.

Host defense in respiratory infections

Respiratory defenses against infection involve a diverse and complex system. Mechanical barriers limit exposure of the respiratory tract to potential pathogenic organisms, whereas the mucociliary apparatus and cough reflexes work to expel any microbes that may bypass the initial defenses. When microorganisms have gained entry to the lower respiratory tract, the alveolar macrophage and recruited phagocytes may eliminate the culprits before active infection can be established. Only after the failure of the innate immune defenses is a specific immune response mounted. Examination of clinical defects in host defense allows one to understand the importance of the multitude of components of the lung's immune defense system.

Residual expression of functional MHC class II molecules in twin brothers with MHC class II deficiency is cell type specific

We examined major histocompatibility complex (MHC) class II expression in B cells, peripheral blood monocytes, activated T cells, epidermal Langerhans cells, monocyte-derived dendritic cells, dermal microvascular endothelial cells (DMEC) and fibroblasts of twin brothers with MHC class II deficiency. Although residual human leucocyte antigen (HLA)-DR expression was found on a subpopulation of epidermal Langerhans cells and a subset of peripheral blood monocyte-derived dendritic cells, the patients' B cells, monocytes and activated T cells were HLA-DR negative. After treatment with interferon-gamma (IFN-gamma), the patients' DMEC expressed HLA-DR but not -DP and -DQ at the protein and mRNA level, whereas IFN-gamma failed to induce HLA-DR expression on dermal fibroblasts. The patients' monocyte-derived dendritic cells were capable of processing and presenting tetanus toxoid to autologous T cells, and patient-derived DMEC induced the proliferation of allogeneic CD4(+) T cells in an MHC class II-restricted fashion, indicating that the observed residual MHC class II surface expression was functional. The findings reported show that the defect encountered in these patients is not necessarily expressed to the same extent in different cell lineages, which is relevant for the understanding of the patients' phenotype and also illustrates that only small amounts of MHC class II are needed to mount a functional cellular immune response in vivo.

Direct inhibition of Bruton's tyrosine kinase by IBtk, a Btk-binding protein

Bruton's tyrosine kinase (Btk) is required for human and mouse B cell development. Btk deficiency causes X-linked agammaglobulinemia (XLA) in humans and X-linked immunodeficiency in mice. Unlike Src proteins, Btk lacks a negative regulatory domain at the COOH terminus and may rely on cytoplasmic Btk-binding proteins to regulates its kinase activity by trans-inhibitor mechanisms. Consistent with this possibility, IBtk, which we identified as an inhibitor of Btk, bound to the PH domain of Btk. IBtk downregulated Btk kinase activity, Btk-mediated calcium mobilization and nuclear factor-kappaB-driven transcription. These results define a potential mechanism for the regulation of Btk function in B cells.

Transplacentally acquired maternal T lymphocytes in severe combined immunodeficiency: a study of 121 patients

A study in 121 infants with severe combined immunodeficiency (SCID) was performed to determine the prevalence of an engraftment by transplacentally acquired maternal T cells and to explore clinical and immunological findings related to this abnormality. Each newly diagnosed patient with SCID presenting with circulating T cells was evaluated for chimerism by performing selective HLA typing of T cells and non-T cells. In patients with engraftment, maternal T cells were characterized phenotypically and functionally, and results were correlated with clinical findings in the patients. Maternal T cells were detected in the circulation in 48 patients; these cells ranged from fewer than 100/microL in 14 cases to more than 2000/microL in 4 cases (median, 415/microL). Clinical signs of graft-versus-host disease (GVHD) were absent in 29 patients. In the other cases, manifestations of GVHD were present, involving the skin and in 14 cases also the liver. Skin GVHD was mild in 8 patients. In these patients, as well as in patients with no signs of GVHD, maternal T cells were predominantly CD8(+) and, with one exception, failed to respond to mitogen stimulation. In 9 patients, manifestations of skin GVHD were prominent. T cells in these cases were predominantly CD4(+) and responded, with one exception, to mitogen stimulation. In 8 of the cases with prominent skin GVHD, the underlying SCID variant was characterized by the absence of B cells. In this study, further understanding is provided of a phenomenon that is responsible for the significant heterogeneity of clinical and immunological findings in SCID.