Interleukin-2 correction of defective in vitro T-cell mitogenesis in patients with common varied immunodeficiency

Seeking Relevant Biomarkers in Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is the most common symptomatic form of primary immunodeficiency. More than 50% of patients in some series suffer from autoimmune or inflammatory complications (the "CVID+" phenotype), and these are not adequately addressed by current treatments. Despite major advancements in genetics, the pathogenesis of the CVID+ phenotype has remained unexplained for most patients, necessitating the need for relevant biomarkers in both the clinic and research settings. In the clinics, reduced isotype-switched memory B cells (≤ 0.55% of B cells) and reduced T cells (CD4) can be utilized to identify those with increased complication risks. Additionally, condition-specific markers have also been suggested for lymphoma (normal or elevated IgM) and progressive interstitial lung disease (increased BAFF, normal or elevated IgM). Additional biomarkers have provided insights into disease pathogenesis, demonstrating wider systemic inflammation (increased LBP, sCD14, and sCD25; expanded ILC3), mucosal defects (increased zonulin, I-FABP), and perhaps reduced anti-inflammatory capability (reduced HDL) in CVID. Most recently, efforts have revealed elevated circulating bioactive bacterial DNA levels - marking microbial translocation and potentially linking the causation of multiple inflammatory changes previously observed in CVID. The implementation of high throughput profiling techniques may accelerate the search of relevant biomarker profiles in CVID and lead to better clinical risk stratification, revealing disease insights, and identifying potential therapeutic targets.

Non-infectious Complications of Common Variable Immunodeficiency: Updated Clinical Spectrum, Sequelae, and Insights to Pathogenesis

Non-infectious complications in common variable immunodeficiency (CVID) have emerged as a major clinical challenge. Detailed clinical spectrum, organ-specific pathologies and associated sequelae from 623 CVID patients followed in New York since 1974 were analyzed, and recent insights to pathogenesis were reviewed. Non-infectious manifestations were present in 68.1% of patients, and they do not tend to be present in isolation. They include autoimmunity (33.2%), chronic lung disease (30.3%), lymphoid hyperplasia/splenomegaly (20.9%), liver disease (12.7%), granulomas (9.3%), gastrointestinal disease (7.3%), lymphoma (6.7%), and other malignancies (6.4%). In the lungs, interstitial disease and bronchiectasis were the most common findings, with lymphoma at this site being a rare (n = 6), but serious, manifestation. Bronchiectasis was not a prerequisite for the development of interstitial disease. In the liver, granulomas and nodular regenerative hyperplasia were the most common. Gastrointestinal disease may affect any segment of the intestinal tract, with lymphoid infiltrations and villous blunting being the leading histologic findings. With progression of organ-specific diseases, a wide spectrum of associated sequelae was observed. Lymphoma was more common in females (P = 0.036)—all B cell types except in one subject. Solid organ transplantations (liver, n = 5; lung, n = 4; combined lung and heart, n = 2) and hematopoietic stem cell transplantations (for B cell lymphoma, n = 1) have rarely been performed in this cohort, with mixed outcomes. Recent identification of monogenic defects, in ~10–30% of various CVID cohorts, has highlighted the molecular pathways that can affect both antibody production and broader immune regulation. In addition, cellular defects in both innate and adaptive immune systems are increasingly recognized in this syndrome.

Common variable immune deficiency: Dissection of the variable

Starting about 60 years ago, a number of reports appeared that outlined the severe clinical course of a few adult subjects with profound hypogammaglobinemia. Puzzled by the lack of family history and adult onset of symptoms in most, the name "acquired" hypogammaglobinemia was given, but later altered to the current name common variable immune deficiency. Pathology reports remarked on the loss of lymph node architecture and paucity of plasma cells in lymphoid tissues in these subjects. While characterized by reduced serum IgG and IgA and often IgM, and thus classified among the B-cell defects, an increasing number of cellular defects in these patients have been recognized over time. In the early years, severe respiratory tract infections commonly led to a shortened life span, but the wide spread availability of immune globulin concentrates for the last 25 years has improved survival. However, chronic non-infectious inflammatory and autoimmune conditions have now emerged as challenging clinical problems; these require further immunologic understanding and additional therapeutic measures. Recent study of this phenotypic syndrome have provided an increasingly fertile ground for the identification of autosomal recessive and now more commonly, autosomal dominant gene defects which lead to the loss of B-cell development in this syndrome.

IgH sequences in common variable immune deficiency reveal altered B cell development and selection

Common variable immune deficiency (CVID) is the most common symptomatic primary immune deficiency, affecting ~1 in 25,000 persons. These patients suffer from impaired antibody responses, autoimmunity, and susceptibility to lymphoid cancers. To explore the cellular basis for these clinical phenotypes, we conducted high-throughput DNA sequencing of immunoglobulin heavy chain gene rearrangements from 93 CVID patients and 105 control subjects and sorted naïve and memory B cells from 13 of the CVID patients and 10 of the control subjects. The CVID patients showed abnormal VDJ rearrangement and abnormal formation of complementarity-determining region 3 (CDR3). We observed a decreased selection against antibodies with long CDR3s in memory repertoires and decreased variable gene replacement, offering possible mechanisms for increased patient autoreactivity. Our data indicate that patient immunodeficiency might derive from both decreased diversity of the naïve B cell pool and decreased somatic hypermutation in memory repertoires. The CVID patients also exhibited an abnormal clonal expansion of unmutated B cells relative to the controls. Although impaired B cell germinal center activation is commonly viewed as causative in CVID, these data indicate that CVID B cells diverge from controls as early as the pro-B stage, cell and suggest possible explanations for the increased incidence of autoimmunity, immunodeficiency, and lymphoma CVID patients.

Cytokines in common variable immunodeficiency as signs of immune dysregulation and potential therapeutic targets - a review of the current knowledge

Common variable immunodeficiency (CVID) is characterized by low levels of circulating immunoglobulins and compromised specific antibody response leading to frequent infections. Cytokines play an important role in the orchestration of the antibody response. Several previous studies have attempted to identify distinct cytokines responsible for the inflammatory changes and different manifestations of CVID, but there are conflicting results regarding the cytokine profiles in CVID patients. In light of this, an extensive review regarding the level of various cytokines and their potential therapeutic role in CVID patients was performed. This review delineates the contribution of interleukin (IL)-1, IL-2, IL-4, IL-5, IL-6, IL-7, IL-10, IL-12, IL-21, interferons, tumor necrosis factor (TNF)-α, IL-17, APRIL (a proliferation inducing ligand) and BAFF (B cell activating factor) in CVID disease and outline their potential therapeutic implications in these patients.

Characterization of immunologic defects in patients with common variable immunodeficiency (CVID) with intestinal disease

BACKGROUND

Common variable immunodeficiency (CVID) is a heterogeneous disorder commonly presenting with recurrent sinopulmonary infections. In all, 6%-10% of CVID patients develop an inflammatory bowel disease (IBD)-like disorder, making these patients a unique population to investigate immune-mediated gastrointestinal disease. This study examined whether defects in peripheral and/or intestinal lymphocytes are involved in disruption of the intestinal mucosa in CVID patients with inflammatory intestinal diseases.

METHODS

Peripheral blood (PB) T cells from healthy controls; CD or UC; CVID; and CVID with IBD were stimulated for 48 hours with anti-CD3+CD28 or phytohemagglutinin (PHA) + phorbol 12-myristate 13-acetate (PMA); cytokine production was measured by enzyme-linked immunosorbent assay (ELISA). Cytokine expression from unstimulated lamina propria lymphocytes (LPLs) was compared by real-time polymerase chain reaction (PCR). Immunohistochemistry of mucosal biopsies was performed. Cell populations were quantified by morphometry.

RESULTS

CVID/IBD PB T cells stimulated by anti-CD3+CD28 had trends for reduced IL-2, IL-10, IFN-γ, and TNF-α compared to controls. These differences were not apparent following stimulation by PHA/PMA. Constitutive production of inflammatory cytokines by LPLs was not detected. Histologically, CVID patients had reduced/absent plasma cells with reductions in intestinal IgM and IgA. CVID patients with and without gastrointestinal (GI) disease exhibited increased CD3+ T cells, specifically CD8+, in the colon compared to normal and IBD controls, suggesting immune dysregulation.

CONCLUSIONS

Intestinal inflammation in CVID patients with IBD-like disease may be mediated by abnormal cytokine production through a T-cell receptor-mediated pathway. However, the variability observed suggests multiple, rather than singular, mechanisms are involved. Histologic features such as reduced intestinal plasma cells and lack of intestinal immunoglobulins may be useful markers in diagnosing CVID in a patient with GI disease refractory to conventional therapies.

T-cell response to viral antigens in adults and children with common variable immunodeficiency and specific antibody deficiency

Several T cell abnormalities have been described in common variable immunodeficiency (CVID), a B cell disorder of mainly unknown origin. A subset of CVID patients suffers from frequent reactivations of herpes viruses. We studied T cell function in CVID [and in a subset of paediatric patients with specific antibody deficiency (SAD)] by measuring T cell proliferation and cytokine production in response to herpes virus-antigens in paediatric CVID patients (n=9) and paediatric SAD patients (n=5), in adult CVID patients (n=14) and in healthy controls. Paediatric CVID patients, but not SAD patients, displayed moderately increased CD8+ T cell proliferation in response to cytomegalovirus, human herpes virus type 6B (HHV6-B) and herpes simplex virus compared to controls. CD8+ T cell responses in adult CVID patients tended to be increased in response to cytomegalovirus and herpes simplex virus. In response to stimulation with herpes virus antigens, the proinflammatory cytokines interleukin (IL)-1beta, IL-6, tumour necrosis factor (TNF)-alpha and interferon inducible protein (IP)-10 were produced. Overall, no major differences were detected in cytokine production upon stimulation between patients and controls, although higher IL-10 and IL-12 production was detected in paediatric patients. In conclusion, cellular immunity against herpes virus antigens appears undisturbed in CVID patients, although defects in subpopulations of CVID patients cannot be excluded.

Gastrointestinal manifestations in primary immune disorders

The gastrointestinal tract is the largest lymphoid organ in the body containing T and B lymphocytes, macrophages, and dendritic cells. Despite the fact that these cells are constantly confronted with antigen primarily in the form of food and bacteria, immune responses in the gut are tightly regulated to maintain homeostasis. Without this balance of active immunity and tolerance, mucosal inflammation may ensue, and manifest as Crohn's disease, ulcerative colitis, pernicious anemia, or celiac sprue. Therefore, it is not unreasonable that inflammatory diseases of the gut are commonly encountered in patients with primary immune deficiencies. The exact pathogenesis of gastrointestinal diseases in the setting of primary immunodeficiency remains unknown, however, both humoral and cell-mediated immunity appear to play a role in preventing intestinal inflammation. Patients presenting with atypical gastrointestinal disease and/or failure to respond to conventional therapy should be evaluated for an underlying primary immune disorder in order to initiate appropriate treatment, such as immunoglobulin or in more severe cases bone marrow transplantation, to prevent long term complications.

Common variable immune deficiency: reviews, continued puzzles, and a new registry

BACKGROUND

Common variable immune deficiency (CVID) is a clinically and immunologically heterogenous primary immune deficiency first described more than 50 years ago. The main features are hypogammaglobulinemia, recurrent infections, and other complications. While CVID is considered as a genetic immune defect, and several genes have been reported as leading to the CVID phenotype, one of the most puzzling features of CVID is the sporadic inheritance pattern and the relatively late onset. In most cases, no other family members have any immune defect. The mean age at diagnosis is between 25 and 45 years of age. These features suggest the interplay between either several or numerous genes with or without potential environmental factors.

Combined decrease of defined B and T cell subsets in a group of common variable immunodeficiency patients

Common variable immunodeficiency disease (CVID) is a primary immune disorder affecting B cells and characterized by hypogammaglobulinemia and recurrent infections. To elucidate the clinical and immunological heterogeneity of this condition, we have studied B and T cell subsets in 25 CVID patients. In eleven of them, we observed a remarkable relative expansion of a B cell subpopulation (CD19(hi)/CD21(lo) cells) characterized by the absence of CD23 and the reduced expression of the chemokine receptors CXCR5 and CCR7. Our analyses demonstrated in these patients that the expansion of CD19(hi)/CD21(lo) cells correlates with a selective decrease of circulating naïve and CD21(hi) memory B lymphocytes. The same group of patients displayed a simultaneous severe reduction of naïve CD4+ T cells associated with decreased levels of T cell receptor excision circles. These observations suggest that a combined defect in generation of B and T subpopulations may account for the abnormal immunophenotype characterizing this subgroup of CVID patients.

TLR9 activation is defective in common variable immune deficiency

Common variable immune deficiency (CVID) is a primary immune deficiency characterized by low levels of serum immune globulins, lack of Ab, and reduced numbers of CD27+ memory B cells. Although T, B, and dendritic cell defects have been described, for the great majority, genetic causes have not been identified. In these experiments, we investigated B cell and plasmacytoid dendritic cell activation induced via TLR9, an intracellular recognition receptor that detects DNA-containing CpG motifs from viruses and bacteria. CpG-DNA activates normal B cells by the constitutively expressed TLR9, resulting in cytokine secretion, IgG class switch, immune globulin production, and potentially, the preservation of long-lived memory B cells. We found that CpG-DNA did not up-regulate expression of CD86 on CVID B cells, even when costimulated by the BCR, or induce production of IL-6 or IL-10 as it does for normal B cells. TLR9, found intracytoplasmically and on the surface of oligodeoxynucleotide-activated normal B cells, was deficient in CVID B cells, as was TLR9 mRNA. TLR9 B cell defects were not related to proportions of CD27+ memory B cells. CpG-activated CVID plasmacytoid dendritic cells did not produce IFN-alpha in normal amounts, even though these cells contained abundant intracytoplasmic TLR9. No mutations or polymorphisms of TLR9 were found. These data show that there are broad TLR9 activation defects in CVID which would prevent CpG-DNA-initiated innate immune responses; these defects may lead to impaired responses of plasmacytoid dendritic cells and loss of B cell function.

CD8+HLA-DR+ T lymphocytes are increased in common variable immunodeficiency patients with impaired memory B-cell differentiation

The recently proposed Piqueras classification of common variable immunodeficiency (CVID) patients is based on flow cytometric quantification of IgD class-switched and CD27 membrane-expressing mature blood B cells. But, many patients also have circulating T cells with immunophenotypic abnormalities, often associated with clinical complications, such as splenomegaly, autoimmune disease, lymphoid proliferation and/or granulomatosis. In 50 unselected CIVD patients, classified according to CD27 and IgD B-cell expression, we analyzed T-lymphocyte subsets according to their expression of HLA-DR and intracellular perforin and/or granzyme B in CD8+ T lymphocytes, CCR7 and CD45RA. CD3+DR+ T-lymphocyte percentages, predominantly CD8+DR+, were significantly higher in patients with clinical complications. MB0 classified patients, characterized by fewer CD27+ B cells, had higher percentages of CD8+DR+ T lymphocytes expressing perforin and/or granzyme with a differentiated effector (CCR7- and CD45RA+) phenotype. In contrast, MB2 patients (with normal CD27+ and IgD- B cells) were free of clinical complications and showed no signs of T-cell activation. MB1 patients (normal CD27+ numbers but fewer IgD- B cells) were either clinically normal or had complications. Combining the set of markers described herein might better define homogeneous groups of patients for etiological studies and clearly segregate patients with clinical complications.

Deficient IL-12 and dendritic cell function in common variable immune deficiency

Patients with common variable immune deficiency have reduced serum IgG, IgA, and/or IgM, defective antibody production, and many have cellular abnormalities, including proliferative defects, accelerated T cell apoptosis, and insufficient production of IL-2 and IL-10. Excess monocyte intracellular IL-12 leading to a polarized Th-1-type response which could prevent antibody production has been suggested. Here we found that dendritic cells (DCs) of CVID subjects have a significantly reduced capacity to secrete IL-12, as compared to DCs of normal subjects when cultured with physiologic simulators: LPS (P = 0.0005), TNF-alpha (P = 0.006), or CD40-L fusion protein (P = 0.0004). CVID TNF-alpha or CD40-Ligand matured DCs were also significantly impaired in antigen presentation in mixed lymphocyte culture. Deficient IL-12 production was closely correlated to lymphocyte functions in vitro and to the absolute numbers of CD4 T cells in peripheral blood. While CVID DCs appear morphologically similar to DCs of normal subjects, the lack of IL-12 production and defective antigen presentation demonstrate functional defects. Deficient DC function could lead to attenuated T cell activation and defective immunization, features characteristic of CVID.

Common variable immunodeficiency and the gastrointestinal tract

Common variable immunodeficiency (CVID) is the second most prevalent primary immunodeficiency disorder but clinically the most important. It causes a wide spectrum of symptoms and signs affecting many systems of the body. CVID is a combination of humoral and cell-mediated deficiency, which explains not only why so many systems are affected but also why standard therapy in the form of intravenous immunoglobulin is not always effective. The gastrointestinal tract is the largest immune organ in the body, and it is therefore expected that this immunodeficiency will affect it in some way. The gastrointestinal manifestations of CVID are variable and tend to mimic known diseases, such as celiac sprue, pernicious anemia, and inflammatory bowel disease, but show significant differences on the microscopic level. Many studies continue to confirm a high prevalence of inflammatory, malignant, and infectious gastrointestinal disorders in patients with CVID. The T-cell-mediated defects of this immunodeficiency disorder are thought to be the cause of the majority of the gastrointestinal disorders in CVID and not the antibody deficiency. Therefore, intravenous immunoglobulin alone may be ineffective. Combination therapy with immunomodulators, such as azathioprine and 6-mercaptopurine, may be needed to treat these gastrointestinal manifestations of CVID.

The Complex Genetics of Common Variable Immunodeficiency

Immunoglobulin (lg)A deficiency and common variable immunodeficiency (CVID) are the most common primary immunodeficiency disorders in North America and Europe. These diseases appear to comprise a familial spectrum of immunodeficiency that ranges from partial IgA deficiency to a complete absence of serum immunoglobulin. The CVID phenotype is typically acquired and can spontaneously revert to IgG and IgM sufficiency. Family studies suggest the presence of at least two susceptibility loci within the major histocompatibility complex on the short arm of chromosome 6: one located near the class II region and the other located near the junction between the class III and class I regions. Inheritance of these susceptibility genes may yield an additive risk for the development of immunodeficiency. First-degree family members of patients with CVID are at risk throughout their lives for the development of these diseases and should be monitored with a high index of suspicion.

Therapeutic strategies in common variable immunodeficiency

The treatment of common variable immunodeficiency (CVID) is currently based on the early recognition of the condition and replacement immunoglobulin combined with prompt treatment of infections and complications. The route of administration, dose and frequency of administration of immunoglobulin still vary between centres and countries. Other interventions aimed at overcoming the immunological defects in CVID such as interleukin-2 therapy are being studied but there is as yet insufficient evidence to support their routine use. The treatment of complications such as suppurative lung disease uses principles broadly similar to those used for cystic fibrosis, whereas the granulomatous complications involving the lungs and other organ systems are in need of much more research to define optimum therapies.

Le déficit immunitaire commun variable de l’adulte : étude clinique, biologique et immunologique chez 17 patients

PURPOSE

Common variable immunodeficiency (CVID) is an immune defect characterized by primary hypogammaglobulinemia. Most of the time, clinical manifestations that reveal CVID are recurrent bacterial infections, but auto-immune or granulomatous events may occur.

METHODS

This retrospective study was conducted on 17 patients fulfilling the classical CVID definition. Lymphocyte activation level was evaluated in 12 patients through HLA-DR expression on lymphocytes subsets.

RESULTS

This study includes 17 patients, 7 men and 10 women. The mean age at the first clinical manifestation is 23 years and the mean age at diagnosis is 39 years. Recurrent upper and lower bacterial respiratory tract infections are common to all patients. Abdominal infection due to Mycobacterium avium-intracellulare complex is found in one patient. Digestive events are dominated by chronic diarrhea caused by giardiasis, nodular lymphoid hyperplasia or villous atrophy. Seven patients developed auto-immune conditions (insulin dependent diabetes, idiopathic thrombocytopenic purpura (ITP), rheumatoid arthritis) and 7 patients have a splenomegaly. Non caseating granulomas in the spleen or in lymph node biopsies are found in 3 patients. Ten patients have a T lymphopenia, 2 have a B lymphopenia, 5 have a CD4/CD8 ratio <1, and 6 have T CD4(+) lymphocytes <400/mm(3). The study of HLA-DR expression on lymphocytes subsets shows that 7/12 patients have activated T CD4(+) and/or CD8(+) cells and these patients have auto-immune or tumoral manifestations. The other 5 patients do not have activated T lymphocytes but present with infectious events only.

CONCLUSIONS

Our study allows the separation of patients with CVID according to their T lymphocytes activation level. A patient's classification is necessary to define homogeneous groups of patients to perform genetic and functional studies which will probably reveal heterogeneous molecular abnormalities.

European surveillance of immunoglobulin safety--results of initial survey of 1243 patients with primary immunodeficiencies in 16 countries

A European multicenter study was conducted to obtain information on the current practices of immunoglobulin administration, the policies in use for the surveillance of the risk of hepatitis C virus (HCV) transmission, and the natural history of HCV infection in patients with hypogammaglobulinemia. Data from 1243 patients with primary immunodeficiencies in 16 countries demonstrated that 90% of patients with antibody deficiencies receive intravenous immunoglobulins in an inpatient setting, and 7% of patients are treated with subcutaneous immunoglobulins, mainly at home. Wide variations have been reported regarding the frequency and the type of tests monitored for the surveillance on the risk of viral hepatitis transmission. Only 60% of patients have been tested at least once for HCV RNA detection. Data from 71 HCV-infected patients demonstrated a rapid progression of HCV infection, with end-stage liver disease, in about 40% of patients. Ten percent of patients spontaneously cleared the virus, and about 30% are asymptomatic. Patients with CVID have a worse prognosis than patients with XLA.

Lymphomas of mucosal-associated lymphoid tissue in common variable immunodeficiency

Common variable immunodeficiency (CVID) is a primary immunodeficiency disease characterized by low serum immunoglobulins IgG, IgA, and usually IgM. The central immune deficiency is impaired secretion of immunoglobulins and lack of antibody production; however, T cell dysfunction and a variety of inflammatory complications suggest global immune dysregulation. A number of reports have documented the association of primary immunodeficiency diseases with the development of non-Hodgkin's lymphoma (NHL). In CVID, the risk has been estimated to lie between 1.4% and 7%. As for NHL arising in other immunodeficiency states, the lymphomas in CVID are extranodal and are usually B cell in type. Of 22 B cell lymphomas that have appeared over a period of 25 years in a cohort of subjects with CVID, five lymphomas, appearing in more recently studied subjects, that arose in mucosal sites would be classified as mucosa-associated lymphoid tissue (MALT) lymphomas. MALT lymphomas are low-grade B cell lymphomas that result from a proliferation of neoplastic marginal-zone related cells of lymphoid tissue and tend to occur in organs that have acquired lymphoid tissue due to long-term infectious or autoimmune stimulation. Lymphomas of this kind have not been described in patients with congenital immunodeficiency, although chronic mucosal antigen stimulation is an integral part of these immune deficiency states.

Interleukin-2 liposomes for primary immune deficiency using the aerosol route

This is the first report of aerosol interleukin 2 (IL-2) liposome administration to individuals with immune deficiency. Parenteral IL-2 therapy has shown beneficial effects in some patients with cancer, common variable immunodeficiency (CVID), and human immunodeficiency virus (HIV) but is problematic because of side effects including fever and malaise as well as local swelling (delayed type hypersensitivity like reaction) after each subcutaneous IL-2 injection. Provision of an IL-2:human albumin liposome formulation via the aerosol route had few side effects in a recent clinical trial in cancer patients. Details of good manufacturing practice (GMP) synthesis and analysis of IL-2 liposomes (N= 6 lots) made without albumin carrier protein and placebo liposomes (three lots) are presented. After centrifugation, IL-2 was closely associated with the liposome pellet (99%). Mean diameter of liposomes was 1.1 microm. Patient acceptance, safety, toxicity, and immune effects of IL-2 liposomes were studied in individuals with primary immune deficiency (N = 15) and subsequently, a larger cohort of patients with hepatitis C. Experience in the immune deficient patients is the subject of this report. Placebo liposomes (12 weeks) and IL-2 liposomes (12 weeks) were provided using a nebulizer. Aerosol placebo liposomes and IL-2 liposomes were well tolerated. No changes in chest X-ray or pulmonary function were seen. Since biologic activity of aerosol IL-2 liposomes has been seen in viral disease (hepatitis C), additional studies of aerosol IL-2 liposomes in individuals with hepatitis C and HIV are planned.

Common variable immunodeficiency

Common variable immunodeficiency (CVID) is a common primary immnodeficiency disease, the hallmark of which is hypogammaglobulinemia. Due to the lack of antibodies, patients usually have recurrent bacterial infections, but there are a number of other puzzling manifestations, including inflammatory conditions, autoimmune disease, and the development of lymphomas. Most patients are diagnosed as adults, and delay in the recognition of the antibody defect is common. A number of defects of T cell function and deficits in the memory B cell pool have been identified, but the underlying cause of this defect remains unknown.

Long-term low-dose IL-2 enhances immune function in common variable immunodeficiency

Common variable immunodeficiency (CVID) is a primary immunodeficiency disease characterized by hypogammaglobulinemia and lack of antibody production. Numerous T cell defects have been described, including reduced gene expression and production of IL-2. Since some of the T cell defects could be explained by lack of IL-2, we have been investigating the effects of in vivo IL-2 treatment. Here, a long-acting form of IL-2, PEG-IL-2, was given for 12-18 months to 15 randomly chosen CVID subjects, in comparison to 39 CVID subjects who served as controls. After 6 to 12 months of treatment, T cell proliferative responses to mitogens and to IL-2 were significantly enhanced; proliferative responses to tetanus and candida antigens increased up to 50-fold. Four of eight subjects immunized with the neoantigen bacteriophage &phi;X 174 displayed increased antibody responses after treatment. Treated subjects recorded reduced, but not overall statistically significant, days of bronchitis, diarrhea, and joint pain. These data indicate that IL-2 might serve as an adjuvant to therapy in some subjects with CVID, enhancing T cell functions and reversing T cell anergy in most.

Common variable immunodeficiency treated with a recombinant human IgG, tumour necrosis factor-alpha receptor fusion protein

Common variable immunodeficiency (CVI) is characterized by a failure in B-cell differentiation and impaired immunoglobulin secretion, but with a variable clinical presentation, including the development of sarcoidal granulomas and autoimmune diseases, as well as an increased incidence of malignancies. We present a 21-year-old white man who carried a diagnosis of juvenile rheumatoid arthritis and presented 6 years later with scarring alopecia showing sarcoidal granulomas. Further work confirmed the diagnosis of CVI, and with increasing systemic symptoms, it was elected to treat the patient with a tumour necrosis factor (TNF)-alpha antagonist, a TNF-alpha receptor IgG1 fusion protein. The patient showed improvement in his systemic symptoms and some hair regrowth after 3 months of therapy, and continued improvement in his systemic disease with only mild scalp hair thinning in the areas of prior involvement after almost 1 year of therapy. CVI and sarcoid may have overlapping clinical and immunological findings. Previous therapies for CVI, including intravenous immunoglobulin, have not altered the mortality of the disease. TNF-alpha is a primary cytokine and is elevated in CVI, and specific inhibition of TNF-alpha in this patient was effective in moderating his disease, including his skin disease.

Common variable immunodeficiency

Common variable immunodeficiency (CVI) is a heterogeneous immunodeficiency syndrome characterized by hypogammaglobulinemia, recurrent bacterial infections, and a variety of immunological abnormalities. In addition to recurrent infections, patients with this syndrome also suffer from an increased incidence of autoimmune disease and malignancy. Because the spectrum of associated diseases is broad, patients with CVI are seen by a variety of medical specialists. In this review, the pathogenesis, clinical manifestations, diagnosis, and treatment of CVI are discussed.

Characterization of the T cell receptor repertoire in patients with common variable immunodeficiency: oligoclonal expansion of CD8(+) T cells

Common variable immunodeficiency is characterized by an impairment in antibody production of at least two immunoglobulin isotypes, and abnormalities of both B and T cells have also been described. In this study, a profound alteration of the T cell receptor repertoire was noted, especially in CD8(+) T cells, in CVID patients when compared to a control group. However, the higher number of oligoclonally expanded populations seen in the patient group was not dependent on age, whereas in the control group an age-related accumulation of these populations was noted. Expansion of CD8(+) CD28(-) T cells in these patients is strongly correlated with T cell receptor repertoire restriction. Furthermore, analysis of cytokine production showed a statistically significant increase in IFN-gamma secretion in the patient group. Lastly, CD94 and perforin were expressed at increased frequencies on CD8(+) T cells in the patient group when compared to the control group. We speculate that these findings support the concept that CD8(+) T cells may play an important regulatory role in CVID.

Enhanced apoptosis of T cells in common variable immunodeficiency (CVID): role of defective CD28 co-stimulation

CVID is a primary immune disorder in which hypogammaglobulinaemia may be associated with a number of T cell defects including lymphopenia, anergy, impaired lymphocyte proliferation and deficient cytokine secretion. In this study we show that T cells of CVID subjects, in comparison with control T cells, undergo spontaneous apoptosis in culture and markedly accelerated apoptosis after gamma-irradiation. Although costimulation of the CD28 receptor following engagement of the TCR/CD3 receptor normally provides a second signal necessary for IL-2 secretion, CD28 costimulation in CVID does not significantly increase IL-2 production, nor does this combination of activators enhance the survival of irradiated CVID T cells, as it does for cultured normal T cells. Addition of IL-2 enhances CVID T cell survival, suggesting that the IL-2 signalling pathways are normal. CVID T cells have similar expression of Bcl-2 to control T cells. CD3 stimulation up-regulates T cell expression of bcl-xL mRNA for normal T cells, but anti-CD28 does not augment bcl-xL expression for CVID subjects with accelerated apoptosis. Defects of the CD28 receptor pathway, leading to cytokine deprivation and dysregulation of bcl-xL, could lead to poor T cell viability and some of the cellular defects observed in CVID.

Common variable immunodeficiency: clinical and immunological features of 248 patients

Common variable immunodeficiency (CVI) is a primary immunodeficiency disease characterized by reduced serum immunoglobulins and heterogeneous clinical features. In these studies we describe the clinical and immunological status of 248 consecutively referred CVI patients of age range 3-79 years who have been followed for a period of 1-25 years. The median age at the time of onset of symptoms was 23 years for males and 28 years for females; the mean age at which the diagnosis of CVI was made was 29 years for males and 33 years for females. Forty percent of patients had impaired T cell proliferation to one or more mitogens; lymphocyte transformation to mitogens was directly related to the level of the serum IgG. Females at all ages had higher levels of serum IgM than males. Survival 20 years after diagnosis of CVI was 64% for males and 67% for females, compared to the expected 92% population survival for males and 94% for females. Parameters associated with mortality in this period were lower levels of serum IgG, poorer T cell responses to phytohemagglutinin, and, particularly, a lower percentage of peripheral B cells (P < 0.006).

CD95 expression and function on lymphocyte subpopulations in common variable immunodeficiency (CVID); related to increased apoptosis

Apoptosis is now recognized as a central process of development and disease, and it has been proposed as one of the mechanisms that may account for the lymphopenia seen in some diseases. In this study we measured spontaneous apoptosis and CD95 expression on different cell subpopulations from CVID patients, using flow cytometric techniques. We divided our patients into two groups according to their CD4+ and CD4+CD45RA+ cell counts. Our results clearly show increased spontaneous apoptosis and CD95 expression on the CD4+ and CD4+CD45RA+ subsets from lymphopenic CVID patients compared with normal subjects and disease controls. Interestingly, our lymphopenic CVID patients presented a profound reduction in absolute counts, mainly affecting the CD4+CD45RA+ subpopulation. We also found a statistically significant direct correlation between absolute numbers of CD4+CD45RA+ T cells and spontaneous apoptosis on the same subset in CVID patients, but attempts to induce CD95-mediated apoptosis were unsuccessful despite increased CD95 expression on CD4+ T cells. These findings suggest that apoptosis could be one of the mechanisms implicated in the significant lymphopenia present in these patients.

Peripheral T cell lymphoma in a patient with common variable immunodeficiency disease: case report and literature review

This report documents the occurrence of a peripheral T cell lymphoma arising in the bone marrow and liver of a patient with common variable immunodeficiency disease. The T cell origin of this lymphoma was demonstrated by immunohistochemical phenotyping and gene rearrangement studies and was not associated with EBV infection of the lymphoma cells. The frequency and characteristics of lymphomas complicating CVID are reviewed.

IL-10 production in common variable immunodeficiency

Common variable immunodeficiency, (CVI) is a heterogeneous primary immunodeficiency disease in which there are T and B cell defects. Since IL-10 in conjunction with anti-CD40 promotes secretion of IgG, IgA, and IgM by CVI B cells, these studies were performed to investigate IL-10 production in CVI. Mitogen or anti-CD3 stimulated CVI peripheral blood mononuclear cells, or isolated T cells produced an insignificant amount of IL-10 over background levels. CVI monocyte IL-10 production was substantial and greater than that of normal controls. Anti-IL-10-neutralizing antibody strongly enhanced CVI T cell proliferative responses to PHA, but only to an insignificant extent, soluble antigens. IL-2 plus anti-IL-10 enhanced CVI proliferative responses to antigens significantly more over baseline than for cells of similarly tested normal controls. These data suggest that CVI T cell secretion of IL-10 is deficient, but that monocyte-derived IL-10, plus a relative lack of IL-2 production, could contribute to the defects of cell proliferation in this disorder.

Sarcoidosis and common variable immunodeficiency. Report of 8 cases and review of the literature

The true incidence of sarcoidosis in common variable immunodeficiency (CVID) is unknown. We report here 8 cases of sarcoidosis among 80 patients with CVID followed in our clinics, along with 22 well-documented cases reported in the literature. Sarcoidosis, therefore, represents an important entity to consider among patients with CVID who exhibit clinical, radiographic, laboratory, and biopsy findings compatible with sarcoidosis. Conversely, the diagnosis of CVID should be considered in patients with sarcoidosis who do not exhibit the characteristic hypergammaglobulinemia and who have a history of recurrent infections. Although many features of sarcoidosis are similar in patients with CVID to those in patients with sarcoidosis alone, there are many important differences. Patients with CVID in whom sarcoidosis develops present with hypogammaglobulinemia rather than hypergammaglobulinemia and have a higher prevalence of recurrent infections, thrombocytopenia, and splenic involvement. Steroids, in most cases, appeared helpful in reducing adenopathy and splenomegaly, improving uveitis, lowering serum alkaline phosphatase, and reversing hematologic abnormalities. The underlying pathophysiology responsible for the association of these 2 disorders in the same patient remains obscure. However, as more patients are identified, it may be possible to gain a better understanding of the immunologic defect responsible for the dual presentation of these 2 relatively uncommon diseases.

Analysis of a family containing three members with common variable immunodeficiency

BACKGROUND

Common variable immunodeficiency (CVID), a diverse immunodeficiency syndrome characterized by low immune globulin levels and recurrent infections, has been observed in families with the HLA A1 B8 DR3 haplotype.

METHODS

We report a two-generation family with three members affected by CVID. Immunoglobulin levels, antibody titers, lymphocyte marker analyses, T cell proliferation assays, and HLA typing were performed on the affected family members.

RESULTS

Studies of the affected patients revealed low levels of immunoglobulin G and A; normal tetanus, rubella and rubeola antibody titers; low B cell numbers; normal T cell numbers; normal CD4/CD8 ratios and normal lymphocyte proliferation studies. HLA typing did not reveal the HLA A1 B8 DR3 haplotype previously associated with familial CVID.

CONCLUSION

We report a family with a unique presentation of CVID involving possible genetic inheritance other than the HLA A1 B8 DR3 haplotype and possessing lymphocyte characteristics distinct from those usually seen in sporadic CVID.

Defects in antigen-driven lymphocyte responses in common variable immunodeficiency (CVID) are due to a reduction in the number of antigen-specific CD4+ T cells

T cells from patients with CVID have defects that may relate to the failure in vivo of B cell production of antibodies. Antigen-driven responses of T cells from CVID patients and normal subjects have been assessed by measuring DNA synthesis in vitro. Low density cells enriched for antigen-presenting dendritic cells were pulsed with purified protein derivative (PPD) and cultured with autologous T cells. Overall, T cells from CVID patients showed a significantly low mean response to PPD, although non-specific DNA synthesis induced in CVID T cells by IL-2 was within the normal range. However, mean PPD-specific T cell responses in CVID were not restored by IL-2 irrespective of the presence of monocytes. Depletion of CD8+ cells also failed to restore the mean PPD response of CVID CD4+ T cells. Limiting dilution analysis showed that in CVID there was a reduced frequency of antigen-specific cells within the T cell preparations. The mean frequency of the PPD-specific T cells in cultures from patients vaccinated with bacille Calmette-Guérin (BCG) was reduced to 1 in 109,000 T cells compared with 1 in 18,600 T cells in BCG-vaccinated normal donors. These data show that the reduced PPD-specific response in CVID is due to a partial peripheral loss of antigen-specific cells.

Immunologic effects of low-dose polyethylene glycol-conjugated recombinant human interleukin-2 in common variable immunodeficiency

Children or adults with the primary immunodeficiency disease, common variable immunodeficiency (CVI), have abnormally low levels of at least two of the three serum Ig isotypes. Although there appear to be intrinsic B cell defects, many have poor T cell proliferation and deficient secretion of IL-2, IL-4, IL-5 interferon-gamma, and B cell differentiation factor. Because the addition of various T cell factors can enhance Ig secretion in vitro in CVI, we have hypothesized that the B cells in this disease may be defective because they lack appropriate investigating the in vivo effects of recombinant IL-2 using a new biologic, polyethylene glycol-conjugated recombinant IL-2 (PEG-IL-2). In these studies, CVI patients were treated with weekly subcutaneous injections of PEG-IL-2. After 12 weeks, each patient had enhanced T cell proliferation, normal IL-2 production, boosted BCDF secretion, and B cells responsive to differentiation signals. During PEG-IL-2 treatment, four of five patients produced detectable serum antibody to keyhole limpet hemocyanin. These data suggest that CVI, which has the phenotype of B cell deficiency, may be caused by a lack of appropriate T cell signals for B cell maturation.

Breakthroughs in the understanding and therapy of primary immunodeficiency

In the 40 years since Ogden Bruton discovered agammaglobulinemia, more than 50 additional immunodeficiency syndromes have been described. Until recently, there was little insight into the fundamental problems underlying a majority of these conditions. Recently, however, the molecular bases of three X-linked immunodeficiency disorders have been reported. These include X-linked immunodeficiency with hyper IgM, X-linked agammaglobulinemia, and X-linked severe combined immunodeficiency. These remarkable accomplishments have been made possible through a combination of new knowledge of molecular signaling mechanisms between and within cells of the immune system and greatly improved approaches to disease loci mapping within the human genome. Improvements in the therapy of immunodeficiency diseases have been impressive, and the development of generally safe and effective intravenous immunoglobulin preparations and T cell depletion techniques that permit the use of non-HLA-identical bone marrow donors have been the most important advances over the past 14 years. The identification and cloning of the genes for several of the primary immunodeficiency diseases have obvious implications for potential future somatic cell gene therapy for these patients. The rapidity of these advances suggests that soon there will be many more to come.

Defective CD2 T cell pathway activation in common variable immunodeficiency (CVID)

Clonal T cell expansion requires simultaneous activation of the TCR and secondary signals, e.g. CD2, CD4, CD28. Interference of CD2/CD58 interaction with MoAbs abrogates the primary immune response and antibody production. Given this functional importance of CD2/CD58 interaction for the generation of specific immune responses, we demonstrate for the first time a defective CD2 pathway activation in patients with CVID (seven children and four adults). The costimulatory effect of monocytes upon CD2-triggered proliferation was significantly impaired in CVID patients: 4.080 ct/min versus 20.769 ct/min in controls (P < 0.05). Second, IL-1, which is a strong comitogenic factor for activation via CD2 in normal T cells, showed a defective amplifier function of the CD2 pathway in most patients (median 1.714 ct/min in patients versus 17.521 ct/min in controls; P < 0.05). In addition, by using a mitogenic combination of CD2 plus CD45 MoAb, median proliferation of T cells was severely depressed in patients: 10.577 ct/min versus 34.685 ct/min in controls (P = 0.005). In conclusion, the marked dysfunction seen in responsiveness to phytohaemagglutinin (PHA) (median 24.594 ct/min in patients versus 52.229 ct/min in controls; P < 0.001) and after CD2 triggering, together with the unaffected response to TCR-CD3, suggest that the T cell deficiency in CVID is in part due to deficiencies in the CD2 pathway. Since direct activation of protein kinase C(PKC) by phorbol ester restores defective T cell responses to normal, our results suggest that an early signal-transducing defect might exist at a step proximal to PKC activation in patients with CVID.

Failure in antigen responses by T cells from patients with common variable immunodeficiency (CVID)

Antigen-driven responses by T cells from patients with CVID and normal subjects have been assessed. Low-density cells enriched for antigen-presenting dendritic cells were cultured with T cells using a 20-microliters hanging drop system. T cells from all subgroups of CVID patients showed markedly reduced responses to the recall antigens purified protein derivative (PPD) or tetanus toxoid, whereas responses by cells from patients with X-linked agammaglobulinaemia, used as a disease control, were in the normal range. However, primary allo-stimulation of CVID T cells was normal. CVID cells from two patients failed to respond to stimulation with a neoantigen, an HIV env peptide, under conditions where normal T cells did respond. These data illustrate a profound defect in antigen-stimulated T cell proliferation in vitro in all groups of CVID patients, but do not distinguish whether the defect is in the presenting cell or in the T lymphocyte. In vivo, germinal centre B cells are thought to present antigen to primed T cells to obtain essential signals (e.g. CD40 ligand and IL-2) for B cell survival and progression to immunoglobulin secretion. A failure of antigen-specific T cell function in vivo in CVID would thus not provide the primed T cells needed for B cell rescue, and could be the primary defect leading to the low immunoglobulin production in this condition.

CD40 ligand expression is defective in a subset of patients with common variable immunodeficiency

Common variable immunodeficiency (CVI) is characterized by hypogammaglobulinemia and recurrent bacterial infections due to failure of CVI B cells to differentiate in vivo into immunoglobulin-secreting plasma cells. We hypothesized that T-cell dysfunction resulting in abnormal contact-mediated B-cell activation may play a prominent role in the failure of CVI B cells to produce specific antibody. We have previously shown that B-cell proliferation and IgE production after stimulation with anti-CD40 and interleukin (IL) 4 were normal in 22 CVI patients evaluated, indicating that CVI B cells respond to signals delivered via CD40. Here we report that CD40 ligand (gp39) mRNA expression by activated lymphocytes from CVI patients (n = 31) as a group was significantly depressed (P < 0.0001) compared with normal controls (n = 32). gp39 mRNA expression by activated lymphocytes from 13 CVI patients fell below the normal control range. T-cell surface expression of functional gp39 protein was correspondingly low in those patients with gp39 mRNA levels below normal control range and normal in patients with gp39 mRNA levels within normal control range. In CVI patients as a group, gp39 mRNA levels correlated with IL-2 mRNA levels (P < 0.002, r = 0.6) and production (P < 0.001, r = 0.7) but not with gene expression or production of other lymphokines evaluated, suggesting an as-yet-undetermined association between gp39 and IL-2 gene regulation. Of the 13 patients whose activated T cells exhibited gp39 mRNA expression below the normal control range, 2 had normal T-cell-derived lymphokine production, whereas the remaining 11 exhibited broader T-cell dysfunction, resulting in IL-2 deficiency, and in some patients deficient production of other lymphokines as well, reflecting a heterogeneity in the underlying mechanisms leading to depressed gp39 expression in these patients. The observation that both gene and surface expression of gp39 by activated T cells is depressed in a subgroup of CVI patients suggests that inefficient signaling via CD40 may be responsible, in part, for failure of B-cell differentiation in these patients.

Co-stimulation with anti-CD28 (Kolt-2) enhances DNA synthesis by defective T cells in common variable immunodeficiency

In normal T cells, an anti-CD28 MoAb (Kolt-2) will synergize with the mitogenic stimuli phytohaemagglutinin (PHA), anti-CD3 (OKT3) or a combination of anti-CD2 antibodies (OKT11 and GT2) in the induction of DNA synthesis. A subgroup of patients with common variable immunodeficiency (CVID) show a defect in DNA synthesis by T cells stimulated in vitro with the above mitogens. We have now investigated whether anti-CD28 will correct the defect. This strategy partially restored DNA synthesis, providing evidence that the CD28 co-stimulatory pathway in CVID T cells is normal. Ligation of CD28 acts through co-stimulating IL-2 secretion. The natural ligand (B7) for CD28 on antigen-presenting cells from CVID patients is expressed normally. We conclude that the defect in CVID T cells lies in pathways that lead to transcription of the IL-2 gene other than that induced by ligation of CD28 with Kolt-2.

Kinetics of hypogammaglobulinemia in patients with common variable immunodeficiency

We investigated the production of immunoglobulin (Ig) in six patients with common variable immunodeficiency and analyzed the courses of their levels of serum Ig for a period of 8-13 years. In all patients, levels of serum IgM, IgG and IgA were markedly low at the first examination, except for the IgM level in one patient. Improvement of serum Ig levels was observed in the patients in whom Ig production of non-T cells at the first examination and C mu gene expression had been detected to a slight degree, but serum Ig levels remained low in the patients in whom Ig production of non-T cells and C mu gene expression had not been detected. Our results suggest that some hypogammaglobulinemia in common variable immunodeficiency develops or improves with age.

Reduced interleukin-2 (IL-2) production in common variable immunodeficiency is due to a primary abnormality of CD4+ T cell differentiation

Common variable immunodeficiency (CVI) is a condition characterized by hypogammaglobulinemia and impaired antibody responses, resulting in recurrent bacterial infections in untreated patients. In addition, affected individuals exhibit an increased incidence of autoimmunity, malignancy, and certain viral infections, suggesting the presence of an underlying generalized immune dysregulation. We have previously described a subgroup of CVI patients in whom T cells within PBMC populations exhibit a selective defect in lymphokine production. IL-2, IL-4, and IL-5 mRNA production was impaired in these patients, while proliferation, IL-2R expression, and c-myc mRNA production were normal. In the present series of experiments, using highly purified CD4+ T cells prepared by negative selection, we show that this lymphokine production defect is a primary abnormality of CVI CD4+ T cells: whereas CD4+ T cells from CVI patients proliferate normally in response to stimulation by PHA, staphylococcal enterotoxin B (SEB), or anti-CD2 antibodies, these stimuli induce significantly less IL-2 production than observed with CD4+ T cells from normal individuals. Furthermore, we show that this IL-2 production defect is not due to an accessory cell abnormality, since it was seen in the presence of normal (allogeneic) accessory cells, and patient accessory cells supported normal amounts of IL-2 production by PHA-stimulated CD4+ T cells obtained from normal individuals. Of interest, we also found that while IL-2 production by CD4+ T cells from CVI patients induced by stimulation with immobilized anti-CD3 antibody was reduced compared to CD4+ T cells from normal control individuals, this reduction was not statistically significant. Furthermore, stimulation of both CVI patient and normal CD4+ T cells with either ionomycin+phorbol myristate acetate or a combination of immobilized anti-CD3 antibody plus anti-CD28 antibody resulted in a 50-fold increase in IL-2 production compared to stimulation with immobilized anti-CD3 antibody alone, and, under these conditions, CVI and normal CD4+ T cells produced equivalent amounts of IL-2. Finally, minor defects in interferon-gamma production by CD4+ T cells from CVI donors were observed, but these were less severe than the IL-2 production defects and were not statistically significant. We conclude that a primary abnormality of lymphokine production exists in the CD4+ T cells of a subset of patients with CVI.(ABSTRACT TRUNCATED AT 400 WORDS)

Increased IL-6 gene expression and production in patients with common variable immunodeficiency

We have studied IL-6 gene expression and production by in vitro stimulated peripheral blood mononuclear cells (PBMC) isolated from common variable immunodeficiency (CVI) patients. A strong hybridization signal for the IL-6 probe was observed in mRNA extracted from phytohaemagglutinin (PHA)- and PHA/phorbol myristate acetate (PMA)-stimulated PBMC from most of 12 CVI patients analysed. IL-6 production by PHA-stimulated PBMC from 28 CVI patients was evaluated in ELISA and found to be significantly (P < 0.0001) higher than in normal controls. IL-6 production, however, did not correlate with the lymphocyte populations examined, nor with the absolute number of monocytes. We have also showed that IL-6 was able to increase IgM secretion by several Epstein-Barr virus (EBV)-transformed cell lines derived from both normal donors and CVI patients, but it failed to modify substantially the amounts of IgM and IgG produced in vitro by PBMC derived from CVI patients and activated with pokeweed mitogen (PWM) or anti-IgM. Our data indicate that IL-6 gene expression and production is increased in CVI, but CVI cells do not respond to IL-6 with increased production of immunoglobulin.

An unusual T-cell surface phenotype in vivo correlates with the failure to proliferate and produce IL-2 in vitro in a patient with common variable immunodeficiency

Stimulation of T-lymphocytes derived from some patients with common variable immunodeficiency (CVID) syndrome results in defective proliferation. The underlying mechanism is related to the inability of stimulated cells to secrete IL-2 while the expression of IL-2 receptor (IL-2R) is normal. We have identified a patient whose peripheral T-cells failed to proliferate and secrete IL-2 upon stimulation. The addition of recombinant IL-2 restored proliferation. The defect did not seem to be caused by accessory cell failure since the patient's adherent cells produced IL-1 and IL-6, and addition of allogeneic irradiated cells did not induce proliferation. Stimulation of CVID T-cells with phorbol esters and Ca2+ ionophore induced both IL-2 secretion and proliferation, indicating the absence of a defect in the transcription and/or translation of the IL-2 gene. The patient's T-cells expressed high levels of CD3. The majority of T-cells expressed the CD38 molecule which is normally found on thymocytes or activated T-cells but not peripheral blood T-cells and HLA-DR, another activation marker. However, CD25 (the IL-2R) and CD1, a marker of more immature thymocytes, were not expressed. Finally, the patient's cells were sensitive to an in vitro corticosteroid treatment. The possibilities that this patient's T-cells represent anergic T-cells or not fully matured thymocytes are discussed.

Immunophenotypical alterations in a subset of patients with common variable immunodeficiency (CVID)

We investigated the expression of surface molecules on lymphocytes from 20 patients with CVID and 40 healthy subjects. Lymphocytes were analysed by dual colour flow cytometry. We identified a subset of patients (8 of 20) characterized by low CD4/CD8 ratio (less than 1.1), expansion of T cells co-expressing the activation marker HLA-DR and significant increase in CD8+ T cells co-expressing CD57. Expression of the adhesion molecules LFA-3 (CD58) and ICAM-1 (CD54) was significantly increased in this subgroup. In addition, within the CD4+ T cells the percentage of CD29+ (memory) cells was increased, while the CD45RA and LAM-1 (Leu-8) antigens were depressed. These results indicate that in a subgroup of CVID patients T cells are activated in vivo and the CD57+CD8+ lymphocyte subpopulation, supposed to comprise functional suppressor T cells, is expanded. We suggest a chronic viral infection in these patients, but it is not clear whether this is primary or secondary to the underlying defect.

Restoration of immunoglobulin secretion in vitro in common variable immunodeficiency by in vivo treatment with polyethylene glycol-conjugated human recombinant interleukin-2

Patients with common variable immunodeficiency (CVI) have decreased immunoglobulin levels resulting in frequent infections. Although previous studies have suggested that the B cell is intrinsically defective, numerous T cell deficiencies, including reduced interleukin-2 (IL-2) production, have been described. Since the addition of T cell cytokines to CVI B cells can increase Ig secretion in vitro, hypogammaglobulinemia in CVI may be due to defective T cell functions. To assess this possibility directly, we treated five CVI patients intravenously with a new biologic, human recombinant IL-2 conjugated to polyethylene glycol. Doses were 250,000 IU/m2 weekly for Weeks 1-4, 500,000 IU/m2 for Weeks 5-8, and 10(6) IU/m2 for Weeks 9-12. During and after treatment, B cells of all patients secreted 10- to 1000-fold more Ig in vitro. There was also a striking improvement in T cell helper activity since T cells of treated patients could induce 10- to 10,000-fold increases in Ig secretion by B cells from normal donors. No increase was seen in serum Igs during the study, but the anti-tetanus antibody of the IgG isotype could be detected in cell culture supernatants. Whether the effects of infused polyethylene glycol IL-2 are mediated through T or B cells, or both, is still unknown. However, these data reinforce the concept that CVI B cells may be competent, but, lacking essential T cell growth factors, in vivo maturation to Ig production does not occur.

Accelerated expression of secreted alpha-chain gene in anaphylactoid purpura

The mechanisms of the elevation of serum IgA levels in anaphylactoid purpura were investigated. Serum IgA levels were significantly elevated within 2 weeks (5 to 14 days for all 12 patients) after onset in patients with anaphylactoid purpura. Serum IgM and IgG were not elevated. Although the percentages of surface IgA-bearing cells were not increased in the patients, the numbers of IgA-secreting cells within 2 weeks after onset in the patients with anaphylactoid purpura were significantly higher than those of controls. In northern blot analysis on lymphocytes, the secreted alpha (alpha s)-chain gene was well expressed compared with the membrane-bound alpha (alpha m)-chain gene, within 2 weeks after the onset of anaphylactoid purpura. Therefore, stimulation by a certain agent or a certain immune response may accelerate expression of the alpha s-chain gene in anaphylactoid purpura.

Reduced secreted mu mRNA synthesis in selective IgM deficiency of Bloom's syndrome

Serum IgM concentrations were low although serum IgG and IgA concentrations were normal in both our patients with Bloom's syndrome. Although the percentages of surface IgM-bearing cells were not reduced, the numbers of IgM-secreting cells were markedly reduced. The membrane-bound mu (microns) and secreted mu (microseconds) mRNAs are produced from transcripts of a single immunoglobulin mu gene by alternative RNA processing pathways. The control of microseconds mRNA synthesis depends on the addition of poly(A) to microseconds C-terminal segment. In both patients, mu mRNA was well detected but microseconds C-terminal mRNA was scarcely detected, suggesting that microns mRNA was well transcribed but microseconds mRNA was not. There was, at least, no mutation or deletion in the microseconds C-terminal coding sequence, the RNA splice site (GG/TAAAC) at the 5' end of microseconds C-terminal segment and the AATAAA poly(A) signal sequence in both patients. Our results suggest that selective IgM deficiency in Bloom's syndrome is due to an abnormality in the maturation of surface IgM-bearing B cells into IgM-secreting cells and a failure of microseconds mRNA synthesis. Moreover, reduced microseconds mRNA synthesis may be due to the defect on developmental regulation of the site at which poly(A) is added to transcripts of the mu gene.