Philip Wood

Frequency of Treg Cells Is Reduced in CVID Patients with Autoimmunity and Splenomegaly and Is Associated with Expanded CD21lo B Lymphocytes

IntroductionCommon variable immunodeficiency is a heterogeneous antibody deficiency syndrome with autoimmune and inflammatory complications in a significant proportion of patients. The study was designed to evaluate the role of T regulatory (Treg) cells in common variable immunodeficiency (CVID) patients with autoimmunity.MethodsThe number and frequency of Treg cells (CD4+, CD25hi, Foxp3+) were evaluated in patients and controls, and Foxp3 expression in different subgroups of CVID patients with common clinical manifestations was compared.ResultsCVID patients had significantly fewer Treg cells than controls, and low frequency of Treg cells was associated with expansion of CD21lo B cells in patients. Patients with autoimmunity had significantly reduced frequency but normal numbers of regulatory T cells, whilst patients with splenomegaly had significant reduction in frequency and number of regulatory T cells.ConclusionFoxp3 is useful on its own or as an adjunct to classify CVID patients although the possibility of reduction in Treg cells as a secondary phenomenon cannot be excluded.

CVID patients with autoimmunity have elevated T cell expression of granzyme B and HLA-DR and reduced levels of Treg cells

Aims Common variable immunodeficiency (CVID) is a primary antibody immunodeficiency with approximately 20% of patients reporting additional autoimmune symptoms. The primary aim of this study was to compare the levels of activated and regulatory T cells (Treg cells) in CVID patients in an attempt to clarify their possible interactions leading to the generation of autoimmunity. Methods Immunophenotyping of T cells was performed by flow cytometry using a whole blood approach. Surface expression of human leukocyte antigen HLA class II DR and intracellular levels of granzyme B in T cell subsets were assessed; Treg levels were measured using CD4 CD25, FOXp3 and CTLA-4. Results CVID patients had higher levels of granzyme B and HLA-DR on CD8+ T cells compared with control values (mean of 59% vs 30% and 45% vs 21%, respectively). Patients also had reduced levels of Treg cells compared with control values (con mean=3.24% vs pat=2.54%). Patients with autoimmunity (5/23) had a similar level of T cell activation markers to the rest of the patients but with lower Treg cells (mean of 1.1%) and reduced CD25 and CTLA-4 expression. Patients with autoimmunity had a higher ratio of activated to Treg cells compared with patients with no autoimmune symptoms. Conclusions These results highlight that reduced levels of Treg cells were associated with elevated levels of activated T cells, suggesting that reduced Treg cells in these patients may have functional consequences in allowing exaggerated T cell responses.

Inherited defects in the interferon-gamma receptor or interleukin-12 signalling pathways are not sufficient to cause allergic disease in children

T-helper (Th)2 cells, which produce the cytokines interleukins (IL)-4, IL-5 and IL-13, dominate T cell responses in allergic diseases. The Th1-type cytokines IL-12 and interferon-gamma (IFNγ) are important in down-regulating Th2 responses to allergens. Patients with defects in the IL-12 receptor (IL-12R) or IFNγ receptor (IFNγR) have abnormal responses to IL-12 or IFNγ and a failure to produce normal levels of IFNγ. Current paradigms of T-helper subset balance would predict a high prevalence of atopic illness in this group. We have studied a cohort of patients ( n =29) with defects in these pathways to assess the prevalence of allergic disease. A questionnaire based on those developed for the International Study of Asthma and Allergy in Childhood (ISAAC) was used in conjunction with analysis of total and specific IgE to common aeroallergens. The prevalence of asthma, eczema and rhino-conjunctivitis (13.7%, 17.5% and 6.8% respectively) in this group was no higher than in comparable populations where prevalences of 13.9%, 7.9% and 13.5% are reported for asthma, eczema and rhinoconjunctivitis respectively. Patients with IFNγR defects had higher rates of clinical atopic illness than control populations and patients with IL-12R defects, with 28.5% prevalences for asthma and eczema, respectively. None of the patients suffered from severe clinical atopic disease. Defects in interferon-gamma receptor/interleukin-12 receptor responses are not sufficient to cause clinical allergic disease. Patients with defects in the interferon-gamma receptor pathway have a higher prevalence of high IgE and clinical atopic illness compared to control populations, supporting the concept that interferon-gamma receptor signalling plays a role in down-regulating type-2 cytokine responses.

Immunotherapy for Primary Immunodeficiency Diseases

The 2 most commonly encountered primary immunodeficiency syndromes in adult practice are antibody deficiency disorders and hereditary angioedema.Immunologic therapy for these disorders has significantly improved patient management. Therapy with immunoglobulin leads to improvement in overall quality of life. With increasing survival rates and decreasing levels of life-threatening infections in patients with primary antibody deficiencies, disease complications are more commonly encountered. Treatment of these complications with monoclonal antibody therapy seems promising and is likely to increase in the future. More recently,several additional agents have become available, including novel drugs targeted at different elements of the disease process.

Downregulation of myeloma-induced ICOS-L and regulatory T cell generation by lenalidomide and dexamethasone therapy.

Multiple myeloma (MM) produces significant cellular and humoral immune defects. We have previously reported that MM induces CD4(+)CD25(+)FoxP3(+) cells (TRegs), via tumour expression of the immune checkpoint regulator, ICOS-L. We sought to define what impact the immunomodulatory drug lenalidomide, alone or with dexamethasone, has on TReg cell generation. Lenalidomide pre-treatment of MM cell lines reduced TReg generation and the concomitant TReg:TEff (CD4(+)CD25(+)FoxP3(-): effector T cells) ratio, as a consequence of reduced ICOSL transcription. Dexamethasone did not affect surface ICOS-L expression but did induce TReg cell apoptosis without impacting on TEff cell survival. Combined lenalidomide and dexamethasone significantly reduced both TReg induction and the TReg:TEff cell ratio. In vivo, serial analysis of the TReg:TEff ratio in MM patients on lenalidomide-dexamethasone therapy revealed a progressive reduction towards age-matched control values, though not complete correction. Our data demonstrate for the first time immune synergism to explain the observed immune-modulation associated with lenalidomide-dexamethasone therapy.

Perioperative reductions in circulating lymphocyte levels predict wound complications after excisional breast cancer surgery.

OBJECTIVE Postoperative wound complications after excisional surgery for primary breast cancer can result in patients requiring additional treatments and delay adjuvant therapy and are associated with worse prognoses.We investigated factors that might predispose patients to wound complications. BACKGROUND A number of patient characteristics have been associated with wound complications, but there is currently no quantitative measure of the risk of their occurrence. Our hypothesis was that wound complications are related, in part, to the immune status of patients. METHODS We recruited patients undergoing surgery for primary breast cancer and determined their circulating levels of various immune cells shortly before and after surgery as a measure of immune status. RESULTS One hundred seventeen patients were recruited; 16 (13.7%) developed wound complications. The following patient and tumor characteristics were associated with higher wound complication rates: diabetes (P = 0.02); larger tumors (T2/3 vs T1; P = 0.02); metastatic axillary nodes (P = 0.006). With respect to immune status, no significant differences in preoperative levels of circulating immune cells were detected between patients who developed wound complications and those who did not. However, patients who developed complications showed greater reductions in lymphocyte levels 4 hours postoperatively than those who did not (P <0.001). Multivariate analyses demonstrated that falls in lymphocyte levels of greater than 20% or 50% 4 hours postoperatively acted as a significant and independent predictor of wound complications (P < 0.005 and P < 0.0001,respectively). CONCLUSIONS Perioperative changes in lymphocyte levels could provide a practical predictive marker for wound complications on which selective antibiotic prophylaxis could be based.

Bialellic Mutations in Tetratricopeptide Repeat Domain 7A ( TTC7A ) Cause Common Variable Immunodeficiency-Like Phenotype with Enteropathy

TTC7A deficiency typically causes severe gastrointestinal manifestations such as multiple intestinal atresia or early-onset inflammatory bowel disease. In some cases, this is associated with severe combined immunodeficiency. Partial loss-of-function mutations appear to be associated with a milder phenotype resulting in common variable immunodeficiency-like condition with enteropathy.

Do defective B cells contribute to reduced Treg cells and autoimmunity in patients with Common Variable Immunodeficiency

Whilst the significance of regulatory T cells (Treg cells) is ell established and B cells with regulatory functions (Bregs) ave also been identified (reviewed in [1]), the possible interacions between regulatory populations of lymphocytes have just tarted to be explored [2]. A model has been recently proposed 3] in which T cell regulation is partially dependent on the activaion of regulatory B cells (defined as CD19hi, IgD+ CD38hi CD24hi D5hi) which act indirectly, via the induction of Foxp3+ reguatory T cells. One of the implications from this report is that atients with primary antibody deficiencies (caused by defects in ature B cell function or differentiation) may display failures of mmune regulation, potentially leading to autoimmunity. Comon Variable Immunodeficiency (CVID), the commonest primary ntibody immunodeficiency requiring treatment [4], provides a uitable human condition in which to test this assertion. It is haracterised by variable peripheral blood B cell numbers but ow serum Immunoglobulin G concentrations, often caused by efect(s) in B cell differentiation leading to recurrent infecions. Interestingly, from a regulatory viewpoint, approximately 0–30% of patients with CVID report additional autoimmune or nflammatory symptoms which are associated with low Foxp3 reg levels [5] suggesting that these patients suffer a partial reakdown of tolerance in addition to reduced antibody levls. As a preliminary investigation, we reviewed immunophenoyping data in 23 confirmed CVID patients (diagnosed using ESID uidelines) and 15 healthy controls using results obtained using ntibody staining and flow cytometry. Local ethics approval was btained. In addition to assessing the levels of Treg cells (CD4+ D25hi Foxp3+) in peripheral blood, we also measured the level f switched memory B cells (CD19+ CD27+ IgD−) as well as he percentage of B cells with a ‘regulatory’ phenotype (defined s CD19+ CD24hi CD38hi and CD19+ CD5+ CD1d+). The results ere compared between patients with and without autoimmuity and with controls. Statistical analysis was performed using he Student’s t-test with values less than 0.05 considered signifiant. Within the patient group, 5/23 patients had laboratory/clinically onfirmed autoimmunity. Of these 4/5 had autoimmune thromocytopenia, 1/5 had autoimmune haemolytic anaemia (both iagnosis based on laboratory tests following exclusion of other ossible causes). Two patients had biopsy proven inflammatory owel disease and ultrasound studies indicated enlarged spleens n 5 patients. We confirmed previous studies [5,6] demonstrating hat that CVID patients with autoimmunity had reduced levels of oxp3+ Treg cells compared to patients with no autoimmune sympoms (means of 1.1% vs 2.9%, p = 0.004) or healthy controls (3.8%) Table 1).