James McNamara

Changes in T-cell subsets identify responders to FcR-nonbinding anti-CD3 mAb (teplizumab) in patients with type 1 diabetes

The mechanisms whereby immune therapies affect progression of type 1 diabetes (T1D) are not well understood. Teplizumab, an FcR nonbinding anti‐CD3 mAb, has shown efficacy in multiple randomized clinical trials. We previously reported an increase in the frequency of circulating CD8+ central memory (CD8CM) T cells in clinical responders, but the generalizability of this finding and the molecular effects of teplizumab on these T cells have not been evaluated. We analyzed data from two randomized clinical studies of teplizumab in patients with new‐ and recent‐onset T1D. At the conclusion of therapy, clinical responders showed a significant reduction in circulating CD4+ effector memory T cells. Afterward, there was an increase in the frequency and absolute number of CD8CM T cells. In vitro, teplizumab expanded CD8CM T cells by proliferation and conversion of non‐CM T cells. Nanostring analysis of gene expression of CD8CM T cells from responders and nonresponders versus placebo‐treated control subjects identified decreases in expression of genes associated with immune activation and increases in expression of genes associated with T‐cell differentiation and regulation. We conclude that CD8CM T cells with decreased activation and regulatory gene expression are associated with clinical responses to teplizumab in patients with T1D.

Antibody Against the Human Immunodeficiency Virus in Commercial Intravenous Gammaglobulin Preparations

In a 6-month study, antibody levels against the human immunodeficiency virus (HIV) were determined in intravenous gammaglobulin preparations and 45 serum samples from 20 patients on gammaglobulin therapy. All 10 lots of a reduced and alkylated preparation and 4 of 8 lots of a pH4/pepsin-treated preparation were seropositive by enzyme-linked immunosorbent assay (ELISA). By Western blot analysis, 8 of 10 lots of the reduced and alkylated preparation and 3 of 8 lots of the pH4/pepsin-treated preparation were positive. Before gammaglobulin infusion, 2 of 45 preinfusion samples were seropositive by ELISA but seronegative by Western blot. After infusion, 15 of 45 samples were seropositive by ELISA, and 8 had antibody against p24 by Western blot. Seropositivity persisted for less than 1 month. Cultures of HIV-positive intravenous gammaglobulin lots were negative for reverse transcriptase activity or viral antigen expression. These results suggest that current methods of preparation either exclude or inactivate HIV.

Alpha-1 antitrypsin treatment of new-onset type 1 diabetes: An open-label, phase I clinical trial (RETAIN) to assess safety and pharmacokinetics

To determine the safety and pharmacokinetics of alpha‐1 antitrypsin (AAT) in adults and children.

Epstein-Barr Virus–Infected Marmoset Cells Do Not Form Lymphomas in Mice with Severe Combined Immunodeficiency

ABSTRACT: EBV has been associated with several malignancies in humans. EBV can also infect marmoset B lymphocytes, which, as opposed to human B cells, are permissive for lytic Epstein-Barr viral replication. Mice with a severe combined immunodeficiency phenotype (SCID mice) are extremely susceptible to EBV-induced lymphomagenesis when inoculated with EBV-infected lymphocytes. We inoculated SCID mice with human and marmoset lympho-blastoid cells infected with the same EBV isolates. The marmoset cells never gave rise to lymphomas, even after the administration of acyclovir or an anti-natural killer cell antibody and observation periods of up to 16 wk. In contrast, the human lymphoblastoid cells nearly always gave rise to lymphomas within 8 wk. Furthermore, human lymphoblastoid cells genetically engineered to permit lytic EBV replication also readily formed tumors in the SCID mouse. Thus, in this system, it is the cellular milieu that is crucial in determining whether a given lymphoblastoid cell will give rise to a tumor, not the EBV isolate harbored by the cell or whether the virus is permitted to undergo lytic replication.

Clinical Efficacy and Safety of Baminercept, a Lymphotoxin β Receptor Fusion Protein, in Primary Sjögren's Syndrome: Results From a Phase II Randomized, Double-Blind, Placebo-Controlled Trial Clinical Efficacy and Safety of Baminercept, a Lymphotoxin β Receptor Fusion Protein, in Primary Sjögren's Syndrome: Results From a Phase II Randomized, Double-Blind, Placebo-Controlled Trial St.Clair et al

OBJECTIVE To evaluate the clinical efficacy and safety of baminercept, a lymphotoxin β receptor IgG fusion protein (LTβR-Ig), for the treatment of primary Sjögrens syndrome (SS), and to explore the possible mechanisms of action of this treatment. METHODS In this multicenter trial, 52 patients with primary SS were randomized in a 2:1 ratio to receive subcutaneous injections of 100 mg of baminercept every week for 24 weeks or matching placebo. The primary end point was the change between screening and week 24 in the stimulated whole salivary flow (SWSF) rate. Secondary end points included the European League Against Rheumatism Sjögrens Syndrome Disease Activity Index (ESSDAI), as well as measurements of select chemokines and cytokines and enumeration of peripheral blood B and T cell subsets. RESULTS The change from baseline to week 24 in the SWSF rate was not significantly different between the baminercept and placebo treatment groups (baseline-adjusted mean change -0.01 versus 0.07 ml/minute; P = 0.332). The change in the ESSDAI during treatment was also not significantly different between the treatment groups (baseline-adjusted mean change -1.23 versus -0.15; P = 0.104). Although the incidence of adverse events was similar between the treatment groups, baminercept therapy was associated with a higher incidence of liver toxicity, including 2 serious adverse events. Baminercept also produced a significant decrease in plasma levels of CXCL13 and significant changes in the number of circulating B and T cells, consistent with its known inhibitory effects on LTβR signaling. CONCLUSION In this trial, treatment with baminercept failed to significantly improve glandular and extraglandular disease in patients with primary SS, despite evidence from mechanistic studies showing that it blocks LTβR signaling.

Two- and Four-Hour Tests Differ in Capture of C-Peptide Responses to a Mixed Meal in Type 1 Diabetes

Mixed-meal tolerance tests (MMTTs) are used in clinical trials to evaluate β-cell function in patients with new-onset type 1 diabetes (1,2). Some trials use a 4-h MMTT, whereas others use an abbreviated (2-h) protocol to reduce investigator and subject burden. In the T1DAL (Inducing Remission in Type 1 Diabetes With Alefacept) trial of patients with new-onset type 1 diabetes, the primary analysis using the 2-h test failed to reach statistical significance ( P = 0.065), but a 4-h test did ( P = 0.019) (3). We investigated the effect of abbreviating the test using data from 186 patients participating in three clinical trials conducted by the Immune Tolerance Network (3–5). Trials were approved by institutional review boards at the participating institutions. Written informed consent or assent was obtained. Each patient contributed up to three 4-h MMTTs, conducted yearly, for a total of 506 paired 2- and 4-h observations. For this analysis, the 4-h assessment, which captures more of the complete hormonal response, was selected as the reference. The percent of the total 4-h C-peptide area under the curve (AUC) captured in the first 2 h ranged from 28% to 72%. Mean AUCs (mAUCs) were computed as 2- or 4-h AUCs divided by duration, 120 or 240 min, respectively. The correlation between the 2- and 4-h mAUCs was 0.98. Generally, the variability of the 2-h test was greater than that of the 4-h test (Fig. 1 A ). After adjusting for baseline, however, the variability was similar. Figure 1 Analysis of 2- and 4-h C-peptide AUCs during MMTTs. The C-peptide …

2. Durable Efficacy of Alefacept in New-Onset Type 1 Diabetes: Evidence for Lasting Modulation of Effector and Regulatory T Cells (231-OR)

SamenvattingType 1 diabetes (T1D) results from destruction of pancreatic beta cells by autoreactive effector T cells. We hypothesized that a combination of targeted depletion and modulation of effector T cell activity by alefacept would result in prolonged preservation of endogenous insulin secretion in patients with newly diagnosed T1D. In a multicenter, randomized, double-blind, placebo-controlled trial we compared alefacept (two 12-week courses of 15 mg intramuscularly per week, separated by a 12-week pause) with placebo in patients with new-onset T1D. Endpoints assessed at 24 months included meal-stimulated C-peptide area under the curve (AUC), insulin use, hypoglycemic events, and immunologic responses.

Targeting effector memory T cells with alefacept in new onset type 1 diabetes: 12 month results from the T1DAL study

BACKGROUND Type 1 diabetes results from autoimmune targeting of the pancreatic β cells, likely mediated by effector memory T (Tem) cells. CD2, a T cell surface protein highly expressed on Tem cells, is targeted by the fusion protein alefacept, depleting Tem cells and central memory T (Tcm) cells. We postulated that alefacept would arrest autoimmunity and preserve residual β cells in patients newly diagnosed with type 1 diabetes. METHODS The T1DAL study is a phase 2, double-blind, placebo-controlled trial in patients with type 1 diabetes, aged 12-35 years who, within 100 days of diagnosis, were enrolled at 14 US sites. Patients were randomly assigned (2:1) to receive alefacept (two 12-week courses of 15 mg intramuscularly per week, separated by a 12-week pause) or a placebo. Randomisation was stratified by site, and was computer-generated with permuted blocks of three patients per block. All participants and site personnel were masked to treatment assignment. The primary endpoint was the change from baseline in mean 2 h C-peptide area under the curve (AUC) at 12 months. Secondary endpoints at 12 months were the change from baseline in the 4 h C-peptide AUC, insulin use, major hypoglycaemic events, and HbA1c concentrations. This trial is registered with ClinicalTrials.gov, number NCT00965458. FINDINGS Of 73 patients assessed for eligibility, 33 were randomly assigned to receive alefacept and 16 to receive placebo. The mean 2 h C-peptide AUC at 12 months increased by 0.015 nmol/L (95% CI -0.080 to 0.110) in the alefacept group and decreased by 0.115 nmol/L (-0.278 to 0.047) in the placebo group, and the difference between groups was not significant (p=0.065). However, key secondary endpoints were met: the mean 4 h C-peptide AUC was significantly higher (mean increase of 0.015 nmol/L [95% CI -0.076 to 0.106] vs decrease of -0.156 nmol/L [-0.305 to -0.006]; p=0.019), and daily insulin use (0.48 units per kg per day for placebo vs 0.36 units per kg per day for alefacept; p=0.02) and the rate of hypoglycaemic events (mean of 10.9 events per person per year for alefacept vs 17.3 events for placebo; p<0.0001) was significantly lower at 12 months in the alefacept group than in the placebo group. Mean HbA1c concentrations at week 52 were not different between treatment groups (p=0.75). So far, no serious adverse events were reported and all patients had at least one adverse event. In the alefacept group, 29 (88%) participants had an adverse event related to study drug versus 15 (94%) participants in the placebo group. In the alefacept group, 14 (42%) participants had grade 3 or 4 adverse events compared with nine (56%) participants in the placebo group; no deaths occurred. INTERPRETATION Although the primary outcome was not met, at 12 months, alefacept preserved the 4 h C-peptide AUC, lowered insulin use, and reduced hypoglycaemic events, suggesting efficacy. Safety and tolerability were similar in the alefacept and placebo groups. Alefacept could be useful to preserve β-cell function in patients with new-onset type 1 diabetes.Background Type 1 diabetes (T1D) results from autoimmune targeting of the pancreatic beta cells, likely mediated by effector memory T cells (Tems). CD2, a T cell surface protein highly expressed on Tems, is targeted by the fusion protein alefacept, depleting Tems and central memory T cells (Tcms). We hypothesized that alefacept would arrest autoimmunity and preserve residual beta cells in newly diagnosed T1D.

1040 ACUTE CHANGES IN CIRCULATING LYMPHOCYTE SUBSETS AND FUNCTION FOLLOWING SPLENECTOMY IN BETA THALASSEMIA MAJOR

In a prospective study of 23 children with Thalassemia Major we demonstrated a 3 fold increase in circulating B cells, and decreased lymphoproliferative responses to PHA and Candida albicans in nonsplenectomized patients of whom 92% were anergic. Splenectomized patients, however, had a 10 fold increase in B cells, as well as a 2 fold increase in T4 and T8 positive cells. This group was not anergic, and had higher in vitro responses to Candida albicans. We hypothesized that the difference between these two groups was related to splenectomy rather than the stage of the disease and/or its treatment. To test this, two patients have been followed prospectively. In comparison to their pre-splenectomy data, there was a 1½ and 5 fold increase in circulating number of B cells and a 2 and 3 fold increase in T cells and a marked increase in lymphocyte responses to Candida albicans and allogeneic lymphocytes. A 2 fold increase in circulating HLA-DR positive cells was noted. 92%. were B cells, less than 1% T cells. The mononuclear spleen cells were not as suppressive as the patients peripheral blood lymphocytes. Peripheral blood lymphocytes from patients were more suppressive than were control lymphocytes. These observations suggest (1) splenectomy is the cause of the increased number of circulating T and B lymphocytes, (2) the elevation in lymphocytes is secondary to redistribution rather than activation (3)increase lymphocyte response is due to a loss of suppressor cells atsplenectcomy.

1009 SELECTIVITY OF THE IMMUNOLOGICAL DISTURBANCES IN A ZINC DEFICIENT INFANT

An infant born prematurely (25wk;720g) presented at six months with acrodermatitis enteropathica. Despite adequate dietary zinc (zn), good weight gain and a normal stooling pattern, the serum zn level was 15 ug/dl (nl range 50-150 ug/dl). Lymphocyte response to the T cell mitogen PHA was normal, but the patient was anergic, and had abnormally high numbers of circulating B cells (1,847 cells/ul;nl 115/cells/ul). The serum IgG level was 140 mg/dl and IgA level was 6 mg/dl. No significant antibody to Tetanus, and no detectable antibody to Pertussis developed after primary immunization. Zn sulphate (2mg/kg/day) rapidly reversed the clinical condition, but immunological abnormalities responded slowly. After three months of zn replacement therapy (with adequate serum zn levels), the infant remained hypogammaglobulinemic, B cells in circulation remained elevated, and the response to the B cell mitogen Pokewood (PWM) was depressed. B cells, however, did respond in vitro to the T cell independent B cell mitogen Staph aureus Cowan (SAC). Responses to allogenic lymphocytes have shown consistent improvement. Overall, the absence of antigen specific responses, the decreased expression of the T3 marker, with normal proliferative responses to PHA and SAC, but not PWM, suggests that prolonged zn deficiency produces chronic disturbances in antigen presentation and/or T cell interactions that respond only slowly to zn replacement therapy. The selectivity of these immunological defects points to those areas of the immune system that may be critically zn dependent.