The differences in T and B cell subsets in thyroid of children with Graves' disease and Hashimoto's thyroiditis

BACKGROUND

The differences between Graves' disease (GD) and Hashimoto's thyroiditis (HT) suggest that changes in the subsets of T cells may have an influence on the course of these reactions.

METHODS

This study included 90 children: 30 with GD, 30 with HT, and 30 healthy children as controls. After thyroidectomy, standard histological examinations and immunohistochemical reactions were performed in paraffin specimens with monoclonal antibodies against T cell markers CD3, CD4, CD8 as well as against CD79 alpha B cells. Ultrathin sections were examined under a transmission electron microscope.

RESULTS

Autoimmune reaction in GD consisted of an increased number of CD4+ T cells (3.17±4.27%) and plasma cells (22.89±8.61%) producing thyroidstimulating hormone-receptors and stimulating thyrocytes to activity. The number of CD8+ T cells was increased in children with HT (20.54±0.68%) as compared with the controls (0.65±0.30%). The autoimmune reaction in the HT children showed antibody dependent cytotoxicity with a low number of CD4+ T cells and an increased number of CD8+ T cells in the thyroid tissue in comparison with that in the GD children and the controls. Plasma cells (31.65±9.11%) in this situation produced the antibodies involved in cytotoxic reactions against thyrocytes.

CONCLUSIONS

Graves' disease is characterized by the increased number of CD4+ T cells and CD8+ T cells. Hashimoto's thyroiditis is characterized by the low number of CD4+ T cells and increased number of CD8+ T cells. CD8+ T cells have cytotoxic properties only in Hashimoto's thyroiditis.

Teleost fish mount complex clonal IgM and IgT responses in spleen upon systemic viral infection

Upon infection, B-lymphocytes expressing antibodies specific for the intruding pathogen develop clonal responses triggered by pathogen recognition via the B-cell receptor. The constant region of antibodies produced by such responding clones dictates their functional properties. In teleost fish, the clonal structure of B-cell responses and the respective contribution of the three isotypes IgM, IgD and IgT remain unknown. The expression of IgM and IgT are mutually exclusive, leading to the existence of two B-cell subsets expressing either both IgM and IgD or only IgT. Here, we undertook a comprehensive analysis of the variable heavy chain (VH) domain repertoires of the IgM, IgD and IgT in spleen of homozygous isogenic rainbow trout (Onchorhynchus mykiss) before, and after challenge with a rhabdovirus, the Viral Hemorrhagic Septicemia Virus (VHSV), using CDR3-length spectratyping and pyrosequencing of immunoglobulin (Ig) transcripts. In healthy fish, we observed distinct repertoires for IgM, IgD and IgT, respectively, with a few amplified μ and τ junctions, suggesting the presence of IgM- and IgT-secreting cells in the spleen. In infected animals, we detected complex and highly diverse IgM responses involving all VH subgroups, and dominated by a few large public and private clones. A lower number of robust clonal responses involving only a few VH were detected for the mucosal IgT, indicating that both IgM(+) and IgT(+) spleen B cells responded to systemic infection but at different degrees. In contrast, the IgD response to the infection was faint. Although fish IgD and IgT present different structural features and evolutionary origin compared to mammalian IgD and IgA, respectively, their implication in the B-cell response evokes these mouse and human counterparts. Thus, it appears that the general properties of antibody responses were already in place in common ancestors of fish and mammals, and were globally conserved during evolution with possible functional convergences.

[The immunocyte subsets and their clinical significance in the peripheral blood of 35 patients with immune thrombocytopenic purpura]

OBJECTIVE

To explore the clinical significance of immunocyte subsets before and after immunosuppressive therapy in the peripheral blood of patients with immune thrombocytopenic purpura (ITP).

METHODS

The percentages of immunocyte subsets in the peripheral blood of 35 patients with ITP and 20 healthy controls were detected by flow cytometry, including CD(3)(+), CD(4)(+), CD(8)(+), CD(+)(56), CD(19)(+) lymphocytes and CD(4)(+)/CD(8)(+).

RESULTS

The percentages of CD(3)(+) T lymphocyte (61.58 ± 6.45)%, CD(4)(+) T lymphocyte (28.38 ± 4.89)% and the ratio of CD(4)(+)/CD(8)(+) 0.99 ± 0.22 in patients with ITP were lower than those in healthy controls [(67.85 ± 4.68)%, (38.00 ± 3.37)%, 1.54 ± 0.13, all P < 0.05]. After immunosuppressive therapy, the percentages of CD(3)(+)T lymphocyte (69.41 ± 5.03)%, CD(4)(+)T lymphocyte (38.17 ± 3.18)% and the ratio of CD(4)(+)/CD(8)(+) 1.60 ± 0.15 recovered to control levels. The percentages of CD(8)(+)T lymphocyte (29.20 ± 4.50)% and CD(19)(+)B lymphocyte (17.74 ± 4.14)% were higher than those in healthy controls [(24.82 ± 2.93)% and (12.09 ± 3.51)%, all P < 0.05]. After the immunosuppressive therapy, the percentages of CD(8)(+)T lymphocyte (24.06 ± 3.02)% and CD(19)(+)B lymphocyte (10.90 ± 3.55)% recovered to control levels. There were no significant difference of the percentage of CD(56)(+) lymphocyte among ITP patients (15.80 ± 2.85)%, ITP patients after immunosuppressive therapy (15.16 ± 2.77)% and healthy controls (16.36 ± 2.75)%.

CONCLUSION

The aberrant immunocyte subsets are involved in the pathogenesis of ITP, and detection of immunocyte subsets might be helpful for the diagnosis and determination of therapeutic outcome of ITP.

Lymphocyte cell counts in middle age are positively associated with subsequent all-cause and cardiovascular mortality

BACKGROUND

There is an association between higher white blood cell counts and all-cause and cardiovascular disease (CVD) mortality. However, little is known about the prognostic significance of circulating lymphocyte and lymphocyte subset numbers.

AIMS

The present study examined the association between T-, CD4-, CD8- and B-cell numbers, and the CD4:CD8 ratio, and all-cause and CVD mortality.

METHODS

Lymphocyte and lymphocyte subset numbers were measured by flow cytometry in a cohort of 4256 male middle-aged Vietnam-era US veterans. Mortality was tracked for 15 years and cause of death was determined from death certificates.

RESULTS

In fully adjusted survival analyses, high circulating T-cells numbers were associated with increased risk of both all-cause [hazard ratio (HR)=1.75, 95% confidence interval (CI) 1.15-2.66] and cardiovascular (HR=3.57, 95% CI 1.53-8.33) mortality. The former association appeared to reflect an effect for high CD8-cells numbers, the latter an effect for high CD4-cell numbers. For all-cause mortality, a high CD4:CD8 ratio was protective (HR=0.58, 95% CI 0.41-0.81). Cardiovascular mortality was also predicted by high B-cells numbers (HR=1.87, 95% CI 1.10-3.17).

CONCLUSION

Circulating lymphocyte and lymphocyte subset numbers may have substantial prognostic significance for both all-cause and CVD mortality.

X‐Linked Agammaglobulinemia: A Survey of 33 Iranian Patients

In order to determine the clinical and laboratory features of X-linked agammaglobulinemia, the records of 33 male patients with XLA were reviewed during 22 years (1980-2002) in the Iranian referral center of primary immunodeficiency disorders. The patients' ages ranged from 20 to 360 months (median 113 months). The median age at the onset of the disease was 8 months and the median age of diagnosis was 48 months, with a median diagnosis delay of 33 months. Almost all of the patients presented common infectious diseases, which were: pneumonia, otitis, diarrhea, sinusitis, and arthritis. During the course of illness, infections in the respiratory tract, gastrointestinal tract, central nervous system, and musculoskeletal system were seen in 93.9%, 75.8%, 33.3%, and 21.2% of XLA patients, respectively. The most common complications of these patients were chronic infections in 75.8% of them, including: chronic otitis media, chronic sinusitis, chronic diarrhea, and bronchiectasis.

Increased serum levels of soluble CD30 in patients with common variable immunodeficiency and its clinical implications

Common variable immunodeficiency (CVID) is a heterogeneous group of disorders, characterized by hypogammaglobulinemia and increased susceptibility to recurrent pyogenic infections, autoimmunity, and malignancies. Twenty-five cases with CVID (18 male and 7 female) and 25 healthy volunteers were investigate in this study. Soluble CD30 (sCD30) serum levels of the subjects were measured and compared. Serum levels of sCD30 in the patients with CVID were significantly increased in comparison with controls (36.93 +/- 32.38 vs 5.27 +/- 1.32 U/ml, P < 0.001). The group of patients with splenomegaly and reversed ratio of CD3+CD4+ T cells/CD3+CD8+ T cells had the highest serum levels of sCD30 (66.01 +/- 43.34 U/ml) in comparison with other patients (P = 0.010). High levels of sCD30 in the CVID patients with splenomegaly and the presence of lymphoma in a patient with the highest level of sCD30 may suggest a soluble form of this marker as a prognostic tool in such diseases.

Toll-like receptor expression and responsiveness of distinct murine splenic and mucosal B-cell subsets

Background

Toll-like receptors (TLRs) are pattern recognition receptors that recognize pathogen associated molecular patterns and trigger innate immunity leading to initiation of adaptive immunity. TLR-mediated activation of dendritic cells (DCs) is known to be a critical event in the initiation of cellular and humoral immune responses. Recent work however suggests that B cells also express TLRs, and that they can be activated via TLR ligands. However, whether such B cell activation occurs only on memory B cells, or whether it can also occur on truly naïve B cells remains controversial. Furthermore, the expression and functional relevance of TLRs on distinct subsets of B cells, which are known to play differential roles in humoral responses is not known.

Methodology/Principal Findings

In this study, we investigated the expression pattern of different TLRs in distinct subsets of murine B cells (naïve, memory, follicular, marginal zone, B-1 and peyer's patch). In contrast to the reported restricted expression pattern of TLRs in human peripheral blood naïve B cells, murine splenic naïve B cells express a variety of TLRs with the exception of TLR5 and 8. Consistent with this relatively broad expression pattern, murine naive B cells proliferate and secrete antibody to a variety of TLR agonists in vitro, in the absence of B-cell receptor cross-linking. In addition, we observed subtle differences in the antibody secretion pattern of follicular, marginal zone, B-1 and peyer's patch B-cell subsets.

Conclusions/Significance

Thus various B cell subsets, including truly naïve B cells, express multiple TLRs, and signaling via such TLRs results in their robust proliferation and antibody secretion, even in the absence of dendritic cell activation, or T-cell help.

Infection by Ascaris lumbricoides and bronchial hyper reactivity: an outstanding association in Venezuelan school children from endemic areas

Asthma and other respiratory diseases have increased in the last years among Venezuelan children from helminthic endemic areas where the infection by Ascaris lumbricoides has been associated to bronchial airway inflammation in parasitized individuals. The aim of this work was to investigate the possible associations between the development of bronchial hyper reactivity and the immune response against A. lumbricoides in urban and rural children. We evaluated 470 school children from rural and urban communities. Pulmonary function tests were performed and >or=20% PC(20) changes were considered as a positive diagnostic of bronchial hyper reactivity. The prevalence and intensity of A. lumbricoides infection was determined by faecal examination. Specific serum IgE levels using a modified ELISA and skin prick tests against A. lumbricoides and the common allergen Dermatophagoides pteronyssinus were done. The number of circulating lymphocyte sub populations was determined by flow cytometry analysis. In rural children, bronchial hyper reactivity was associated with increased specific levels of anti-A. lumbricoides IgE (p<0.0001) and skin test positivity for A. lumbricoides (p<0.0001). The percentage of FEV1 predictive values correlated inversely (p<0.0001) with anti-A. lumbricoides IgE levels. Elevated numbers of circulating CD3+CD4+ and CD20+CD23+ cells were found in rural children with bronchial hyper reactivity compared to their asymptomatic counterparts. They correlated positively with anti-A. lumbricoides IgE levels (p<0.005 and <0.0001, respectively). In contrast, in urban children, bronchial hyper reactivity was associated with elevated anti-D. pteronyssinus IgE levels (p=0. 0089), skin hyper reactivity towards this aero allergen (p=0.003) and to an increase in the number of CD3+CD8+ (p<0.0001). Our results suggest that the IgE response against A. lumbricoides infection may be involved in the development of bronchial hyper reactivity among rural children from endemic areas and also that improved hygienic conditions in the urban environment is associated with increased responses to airborne allergens.

Decreased expression of Kruppel-like factors in memory B cells induces the rapid response typical of secondary antibody responses

Secondary antibody responses are characterized by the rapid kinetics of the responding cells, including the production of larger amounts of serum Ig compared with the primary response. Memory B cells, which are responsible for this phenomenon, undergo greater proliferation and differentiation into Ig-secreting plasma cells than naïve B cells. We have found that memory cells rapidly enter cell division, irrespective of extrinsic stimuli. Microarray analysis of human splenic B cells revealed that naïve cells express higher levels than memory B cells of Krüppel-like factor (KLF) 4, KLF9, and promyelocytic leukemia zinc finger (PLZF), transcription factors important in maintaining cellular quiescence. These genes were down-regulated after activation through CD40 and the B cell receptor. Enforced expression of KLF4, KLF9, and PLZF in memory B cells delayed their entry into division and reduced the number of proliferating cells, such that the behavior of transfected memory cells resembled that of naïve B cells. Thus, the accelerated response of memory B cells correlates with reduced expression of KLF4, KLF9, and PLZF and the subsequent regulatory effects they exert on the cell cycle.

The dynamics of the B follicle: understanding the normal counterpart of B-cell-derived malignancies

The repertoire of B cells secreting antibodies with unique antigen-binding specificities is produced at two stages: a primary B-cell repertoire is formed in the bone marrow through immunoglobulin gene rearrangements, whereas a secondary B-cell repertoire is generated in the peripheral lymphoid organs (spleen, lymph nodes and mucosa-associated lymphoid tissue) through somatic hypermutation and class-switch recombination upon antigen encounter. The latter events take place within highly specialized histological structures, designated B follicles, which are composed of distinct microanatomical compartments namely the follicle centre, lymphocytic corona and marginal zone. Each compartment comprises a particular subset of B cells, characterized by unique properties, thereby reflecting the complexity and variability in the spectrum of defence mechanisms against invading pathogens. The past years have spawned an avalanche of new data and information that encompasses both the structure and function of each compartment and its B cells. This review incorporates up-to-date information on peripheral B-cell differentiation into a challenging working model, thereby pointing to the structural and functional imprint of both the T-cell-dependent and T-cell-independent immune response on the B follicle. As such, this article aims to form an excellent base for a better understanding of the normal counterpart of B-cell-derived haematological malignancies (leukemias and lymphomas).

IL-10 regulation of lupus in the NZM2410 murine model

Multiple studies have reported high levels of IL-10 in SLE patients and in murine models of lupus. IL-10 is a regulatory cytokine mainly produced by B cells, which use this cytokine to support their proliferation, and by myeloid cells, which use IL-10 to reduce proinflammatory responses. IL-10 is also produced by a subset of CD4+ T regulatory cells. Various manipulations of IL-10 levels with repeated administrations of anti-IL-10 neutralizing antibodies, genetic ablation or injections of recombinant cytokine have shown contradictory results, which is likely to reflect the opposite effects of this cytokine on the two major effector arms of lupus pathologenesis, namely B cells and inflammation. We have investigated the role of IL-10 in a novel congenic model of lupus, B6.Sle1.Sle2.Sle3 (B6.TC), which consists of the three NZM2410-derived SLE susceptibility loci combined on a C57BL/6 background. We first investigated in this model the source of elevated IL-10 and shown that it results from a larger number of CD4+ T cells producing the cytokine, and from a greatly increased B1-a cell pool, which is the main IL-10 producing compartment. We have then used AAV-mediated skeletal muscle gene delivery to overexpress IL-10 in young B6.TC mice and follow disease marker expression up to 7 months of age. We show here that continuous overexpression of low levels of IL-10 significantly delayed antinuclear auto-antibody production and decreased clinical nephritis. B cell phenotypes were largely unaffected, while T-cell activation was significantly reduced. This highlighted the pivotal role played by T-cell activation in this model, and suggested that this pathway could be effectively targeted for therapeutic interventions. These results also reinforce the notion that IL-10 exerts multiple functions and commend caution in equating high levels of IL-10 and increased pathogenesis in systemic autoimmunity.

Immune defects in subjects with dysmorphic disorders

Patients with dysmorphic disorders seem to have frequent respiratory infections that may be attributed to associated anatomic or neurological abnormalities, but immune defects may contribute to their susceptibility to infections. We screened subjects with dysmorphic conditions for major hematologic, B-cell and T-cell defects. We studied 84 subjects with dysmorphic disorders: 29 with chromosomal disorders, 27 with single gene disorders, and 28 with unclassified dysmorphic disorders. They were evaluated by physical examination; medical history suggestive of possible immune deficiency; complete blood count; serum immunoglobulin G (IgG), IgA, and IgM levels; and lymphocyte subsets. Low laboratory values (less than fifth percentile for age) were detected in 54.8%; was highest in the chromosomal disorder group (79.3%) followed by the single gene disorder group (55.6%) and was lowest in the unclassified dysmorphic disorder group (28.6%). The most common low values were in the CD19 and CD16/56 lymphocyte subpopulations followed by IgG and IgA levels. None of the subjects had neutropenia or thrombocytopenia. History of significant recurrent infections was noted in five subjects, all of whom had abnormal laboratory values. The highest frequency of abnormal laboratory values was in Down syndrome followed by Turner syndrome and chromosome deletions. We concluded that patients with dysmorphic disorders, particularly those with chromosomal disorders, have a high frequency of various B-cell and T-cell defects that may be contributing to their susceptibility to infection. Studies are needed to further delineate the immunologic defects in that population and to investigate a possible genetic basis at the molecular level.

Novel RAG1 mutation in a case of severe combined immunodeficiency

OBJECTIVE

The recombination activating enzymes RAG1 and RAG2 are essential to the process of V(D)J rearrangement in B and T cells and thus to the development of normal immune function. Mutations in RAG1 or RAG2 can lead to a spectrum of disorders, ranging from typical (B-)(T-) severe combined immunodeficiency to Omenn's syndrome. We present a unique presentation of RAG1 deficiency.

PATIENT

We report on a 6-month-old girl who presented with severe respiratory distress, which continued to progress despite antibiotic therapy but seemed to respond to treatment with corticosteroids. The patient exhibited no erythroderma or eosinophilia, and her lymphoid organs were not enlarged.

RESULTS

Investigation of the immune system showed normal numbers of CD3+ T cells, which expressed either CD4 or CD8. Subsequent analysis of the T-cell receptor demonstrated that nearly all CD3+ T cells were clonal; one clone expressed CD4, whereas the other expressed CD8. The extremely restricted T-cell repertoire and the lack of circulating B cells prompted analysis of the RAG1 gene, which revealed a novel homozygous thymine to cytosine substitution at nucleotide position 2686.

CONCLUSIONS

This case underscores the importance of more extensive evaluation of the immune system even when widely available, standard, flow cytometric analysis shows normal numbers of T cells that express CD4 or CD8, especially in the absence of circulating B cells.

[Response to presurgical stress in outpatient surgery: effects on lymphocyte populations of psychological treatment to prevent surgical anxiety]

OBJECTIVE

To determine the effect of a psychological stress control intervention on lymphocyte populations in patients preparing for outpatient surgery.

PATIENTS AND METHODS

A prospective randomized controlled trial enrolling 74 patients scheduled for major outpatient surgery at the Hospital Universitario de Albacete in Spain. The patients were randomized to a control (n = 37) or experimental group (n = 37). Measurements were recorded at baseline (preoperative visit) and before entering the operating room (just before surgery). The experimental group received treatment in a psychological stress control program consisting of an interview, watching a video, provision of informative literature about the operation and techniques for controlling anxiety. Anxiety was measured with the State-Trait Anxiety Inventory. The General Health Questionnaire (Goldberg) was applied, and lymphocyte populations were assessed (total white cell count; CD3, CD4, CD4RA, CD4RO, CD8, CD56, CD19, and CD56 lymphocyte counts). Values were expressed as means (SD).

RESULTS

The group that received psychological stress prevention therapy had significantly lower CD19 (B lymphocyte) cell counts than did the control group just before surgery. No differences were found between the groups for any other variables.

CONCLUSIONS

Psychological stress control therapy prevents a decrease in B cell populations before outpatient surgery.

Immunohistological analysis of Tannerella forsythia-induced lesions in a murine model

Tannerella forsythia has been implicated as a defined periodontal pathogen. In the present study a mouse model was used to determine the phenotype of leukocytes in the lesions induced by subcutaneous injections of either live (group A) or nonviable (group B) T. forsythia. Control mice (group C) received the vehicle only. Lesions were excised at days 1, 2, 4, and 7. An avidin-biotin immunoperoxidase method was used to stain infiltrating CD4+ and CD8+ T cells, CD14+ macrophages, CD19+ B cells, and neutrophils. Hematoxylin and eosin sections demonstrated lesions with central necrotic cores surrounded by neutrophils, macrophages and lymphocytes in both group A and group B mice. Lesions from control mice exhibited no or only occasional solitary leukocytes. In both groups A and B, neutrophils were the dominant leukocyte in the lesion 1 day after injection, the numbers decreasing over the 7-day experimental period. There was a relatively low mean percent of CD4+ and CD8+ T cells in the lesions and, whereas the percent of CD8+ T cells remained constant, there was a significant increase in the percent of CD4+ T cells at day 7. This increase was more evident in group A mice. The mean percent of CD14+ macrophages and CD19+ B cells remained low over the experimental period, although there was a significantly higher mean percent of CD19+ B cells at day 1. In conclusion, the results showed that immunization of mice with live T. forsythia induced a stronger immune response than nonviable organisms. The inflammatory response presented as a nonspecific immune response with evidence of an adaptive (T-cell) response by day 7. Unlike Porphyromonas gingivalis, there was no inhibition of neutrophil migration.

[Clinical significance of lymphocyte subpopulations and cytokine-producing activity of blood cells in patients with primary myelodysplastic syndrome]

Lymphocyte subpopulation composition and spontaneous production of tumor necrosis factor-alpha (TNF-alpha) by blood cells were studied in 22 and 15 patients with myelodysplastic syndrome (MDS), respectively, who were under immunosuppressive therapy (IST). Patients with hematological response revealed a significantly increased cytotoxic CD8+ lymphocyte concentration and TNF-alpha production. A direct correlation between TNF-alpha production rate and CD8+ lymphocyte level was established. Maximum cytokine-producing activity of blood cells was identified in MDS patients with enhanced erythroid response. The study established a great diversity of MDS, its hypoplastic variants and the prognostic value of spontaneous production of tumor necrosis factor-alpha (TNF-alpha) by blood cells as marker of IST efficacy.

Effect of the B cell superantigen protein A from S. aureus on the early lupus disease of (NZBxNZW) F1 mice

The (NZBxNZW) F(1) mouse develops a spontaneous autoimmune disease process with striking similarities to human systemic lupus erythematosus (SLE). In female (NZBxNZW) F(1) mice, the production of IgG antinuclear antibodies, including antibodies to double-stranded DNA (dsDNA), is associated with the development of a severe immune complex-mediated glomerulonephritis that results in death from renal failure in virtually all animals by 12 months of age. Since B-1 and marginal zone (MZ) cells represent a potential source of pathogenic antibodies and because B cell superantigens have been demonstrated to reduce B-1 and MZ cells in vivo, we tested the effect of repeated injections of the superantigen protein A (SpA) from S. aureus on the disease of this lupus model. We found that weekly intraperitoneal injections of SpA delay the progression of serum anti-DNA IgG and reduce proteinuria early in young female (NZBxNZW) F(1) mice. This superantigen also induced a specific depression in the numbers of peritoneal B-1 cells, as compared to mice treated with a control protein. These results support the role of B-1 cells in the development of the autoimmune disease in this mouse model and suggest that B cell superantigens may be useful in the management of autoimmune conditions.

Lymphocyte subsets in Bell's palsy: immune pathogenesis and outcome prediction

The aim of this prospective study is to define the prognostic significance of lymphocyte subset analysis in children with Bell's palsy. Lymphocyte subgroup analysis in peripheral blood was performed in 17 children with Bell's palsy by using flow cytometry. Before a standard protocol of corticosteroid treatment, patients were categorized into two groups for facial nerve impairment on the basis of the clinical findings: Group 1 (mild to moderate impairment), 7 patients; and Group 2 (severe impairment), 10 patients. Outcome of the patients was evaluated at the end of 3 months follow-up and categorized as satisfactory recovery (n = 12) or unsatisfactory recovery (n = 5). Decreased percentages of B cells (CD19) and T helper/inducer (CD4) subsets were measured in patients with Bell's palsy compared with age-matched healthy control patients. Patients with severe impairment had significantly lower percentages of CD4 and CD19 subsets, whereas patients with mild to moderate impairment had only decreased percentage of CD19 subsets. There was no statistically significant difference in the percentage of lymphocyte subsets between the patients with satisfactory and unsatisfactory recovery. These results provide additional support for cell-mediated immunopathogenesis in patients with Bell's palsy, without any prognostic significance for the outcome.

Association between anticonvulsant hypersensitivity syndrome and human herpesvirus 6 reactivation and hypogammaglobulinemia

BACKGROUND

Anticonvulsant hypersensitivity syndrome (AHS) is a life-threatening, drug-induced, multiorgan system reaction. The identification of predisposing factors is clearly needed to predict the incidence and outcome of AHS; attention has recently been focused on reactivation of human herpesvirus 6 (HHV-6).

OBJECTIVE

To determine whether immunosuppressive conditions that can allow HHV-6 reactivation could be specifically detected in association with the onset of AHS.

DESIGN

We analyzed patients with AHS who were treated during 1997-2002. Two groups of patients receiving anticonvulsants served as controls.

SETTING

Department of Dermatology, Kyorin University School of Medicine, Tokyo, Japan. Patients Ten patients with AHS.

MAIN OUTCOME MEASURES

The results of serologic tests for antibody titers for various viruses, including HHV-6, HHV-6 DNA detection by real-time polymerase chain reaction, immunoglobulin levels by turbidimetric immunoassay, IgG subclass levels by nephelometry, and CD19(+) B-cell counts by flow cytometric analysis, were sequentially assessed.

RESULTS

Serum IgG levels (mean, 745 mg/dL) and circulating B-cell counts (mean, 88/ micro L) in patients with AHS were significantly decreased at onset compared with control groups (P<.001 and P =.007, respectively). These alterations returned to normal on full recovery. Reactivation of HHV-6 as judged by a greater than 4-fold increase in HHV-6 IgG titers was exclusively detected in most patients with AHS associated with decreased IgG levels and B-cell counts.

CONCLUSIONS

A decrease in immunoglobulin levels and B-cell counts can be associated with HHV-6 reactivation and the subsequent onset of AHS. These immunological alterations might be a useful predictor of the development of AHS.

[Importance of immunophenotyping in the diagnosis of B-cell lymphoproliferative diseases ]

The immunophenotyping of the lymphoproliferative diseases is considered to be an integral part of the diagnostic process pointing to the correct classification of the individual diseases and to the choice of the most suitable type of therapy. This article describes the immunophenotype of particular types of B-lymphoproliferative disorders included in the World Health Organization classification (WHO) and the prognostic importance of some markers. The panel of specific monoclonal antibodies directed to B-cell lineage used in our department is displayed.

The immunologic role of thymectomy in the treatment of myasthenia gravis: implication of thymus-associated B-lymphocyte subset in reduction of the anti-acetylcholine receptor antibody titer

BACKGROUND AND PURPOSE

Thymectomy is generally accepted as the major option of treatment for myasthenia gravis. To elucidate the biological role of thymectomy in the treatment of myasthenia gravis, the immunologic characteristics of the thymus was studied in association with the postoperative kinetics of the anti-acetylcholine receptor antibody titer.

MATERIALS AND METHODS

Thirty-four patients with nonthymomatous myasthenia gravis who had positive anti-acetylcholine receptor antibody titer and undergoing extended thymectomy were subjected to the study. Reduction of anti-acetylcholine receptor antibody titer was evaluated in terms of the proportion of anti-acetylcholine receptor antibody titer at 1 year after thymectomy to that before the operation. The numbers of B lymphocytes (CD19(+) cells) and the germinal center B lymphocytes (CD19(+)CD38(high) cells) present in 1 g of the thymic tissue were calculated by flow cytometry.

RESULTS

The proportion of anti-acetylcholine receptor antibody titer at 1 year after thymectomy ranged from 27.5% to 150%. The numbers of B lymphocytes and the germinal center B lymphocytes in 1 g of the thymic tissue ranged from 0.19 x 10(6)/g to 162.8 x 10(6)/g and from 0.09 x 10(6)/g to 33.4 x 10(6)/g, respectively. The proportion of anti-acetylcholine receptor antibody titer at 1 year after thymectomy had a significant inverted correlation with the number of B lymphocytes (P =.002) as well as that of the germinal center B lymphocytes (P =.007).

CONCLUSION

Effectiveness of thymectomy was dependent on predominance of B lymphocytes and the germinal center B lymphocytes in the thymus, suggesting that one of the biological roles of thymectomy in the treatment of myasthenia gravis is removing the thymus-associated germinal centers.

Death-associated protein kinase promoter hypermethylation in normal human lymphocytes

A high frequency of death-associated protein kinase (DAPK) promoter hypermethylation has been noted in B-cell malignancies, head and neck cancers, and other solid tumors, and it has been used as a tumor marker in molecular detection strategies. Low levels of DAPK promoter hypermethylation, ranging from 0.003 to 1.181%, were detected in peripheral blood cells from 75 of 143 (52%) normal subjects by quantitative methylation-specific PCR (Q-MSP). In 10 of 10 selected patients, MSP amplification of a portion of the DAPK promoter followed by PCR product sequencing confirmed dense hypermethylation of the CpG island in their peripheral blood cells. Q-MSP analysis of fluorescence-activated cell-sorted peripheral blood cells from three of these patients demonstrated that a significantly greater proportion of B cells (1.074-6.026%) were DAPK hypermethylated than were T cells, monocytes, or neutrophils, which were <0.06% hypermethylated. Further analysis after sorting of one subject's B cells into IgM+, IgM-, IgG+, and IgG- subpopulations demonstrated that DAPK hypermethylation was predominantly present in the IgM- compared with IgM+ B cells (3.338% versus 0.436%). DAPK promoter hypermethylation was found in IgM- B cells in normal individuals. The same hypermethylation identified in B-cell malignancies may reflect a clonal outgrowth of B cells arising from this compartment and may indicate a susceptibility to neoplastic transformation in a subset of B cells. Normal circulating lymphocytes with DAPK promoter hypermethylation may act as confounding factors in tumor detection based on DAPK hypermethylation.

Critical roles of Pten in B cell homeostasis and immunoglobulin class switch recombination

Pten is a tumor suppressor gene mutated in human cancers. We used the Cre-loxP system to generate a B cell-specific mutation of Pten in mice (bPten(flox/flox)mice). bPten(flox/flox) mice showed elevated numbers of B1a cells and increased serum autoantibodies. Among B2 cells in bPten(flox/flox) spleens, numbers of marginal zone B (MZB) cells were significantly increased while those of follicular B (FOB) cells were correspondingly decreased. Pten-deficient B cells hyperproliferated, were resistant to apoptotic stimuli, and showed enhanced migration. The survival kinase PKB/Akt was highly activated in Pten-deficient splenic B cells. In addition, immunoglobulin class switch recombination was defective and induction of activation-induced cytidine deaminase (AID) was impaired. Thus, Pten plays a role in developmental fate determination of B cells and is an indispensable regulator of B cell homeostasis.

Transitional type 1 and 2 B lymphocyte subsets are differentially responsive to antigen receptor signaling

Mature B-lymphocytes develop sequentially from transitional type 1 (T1) and type 2 (T2) precursors in the spleen. To elucidate the mechanisms that regulate the developmental fate of these distinct B cell subsets, we investigated their biochemical and biological responses following stimulation through the B-cell antigen receptor (BCR). As compared with the T1 subset, T2 cells are more responsive to BCR engagement, as evidenced by their robust induction of activation markers, expression of the prosurvival protein Bcl-x(L), and enhanced proliferation. BCR stimulation of T2 cells leads to the appearance of B cells with mature phenotypic characteristics, whereas T1 cells die. All of these T2 responses are dependent on the BCR signal transducer Bruton's tyrosine kinase, which is dispensable for the T1 to T2 transition. Furthermore, the serine/threonine kinases ERK, p38 MAPK, and Akt are predominantly activated in T2 compared with T1 B cells following BCR cross-linking. We conclude that T1 and T2 B cells respond differentially to BCR engagement via the induction of stage-specific signaling pathways. In turn, these signaling pathways probably govern the development and selection processes that are critical for the formation of the mature B cell compartment.