Monitoring the T-Cell Receptor Repertoire at Single-Clone Resolution

The adaptive immune system recognizes billions of unique antigens using highly variable T-cell receptors. The αβ T-cell receptor repertoire includes an estimated 10(6) different rearranged β chains per individual. This paper describes a novel micro-array based method that monitors the β chain repertoire with a resolution of a single T-cell clone. These T-arrays are quantitative and detect T-cell clones at a frequency of less than one T cell in a million, which is 2 logs more sensitive than spectratyping (immunoscope), the current standard in repertoire analysis. Using T-arrays we detected CMV-specific CD4+ and CD8+ T-cell clones that expanded early after viral antigen stimulation in vitro and in vivo. This approach will be useful in monitoring individual T-cell clones in diverse experimental settings, and in identification of T-cell clones associated with infectious disease, autoimmune disease and cancer

Complement activation during OKT3 treatment: A possible explanation for respiratory side effects

Complement activation during OKT3 treatment: A possible explanation for respiratory side effects. Respiratory side effects that sometimes occur during treatment with anti-CD3 MAb OKT3 might result from pulmonary sequestration of activated neutrophils. Therefore, we studied complement activation in relation to activation and pulmonary sequestration of neutrophils during antirejection treatment with OKT3. In each of nine patients studied, plasma C3a-desarg and C4b/c levels increased compared with pretreatment values already in the first sample taken 15 minutes after the first dose of OKT3 (P < 0.05), with peak values at 15 and 30 minutes, respectively. Levels of neutrophil degranulation product elastase (complexed to α1-antitrypsin) also increased already at 15 minutes after the first dose of OKT3 (P < 0.05), which is before elevated levels of the cytokines TNFα, IL-6 or IL-8 were detectable. In contrast, upon subsequent OKT3 administrations or in the control group treated with methylprednisolone, neither complement activation, cytokine release nor neutrophil degranulation occurred. In five studied patients treated with OKT3, pulmonary sequestration of radiolabeled granulocytes was observed from 3 until 15 minutes after the first dose of OKT3, together with peripheral blood granulocytopenia, which lasted at least 30 minutes. In conclusion, we demonstrate a simultaneous activation of complement and pulmonary sequestration of activated granulocytes immediately following the first dose of OKT3. These phenomena may be involved in the development of respiratory side effects complicating this therapy

Eigenvalue asymptotics for weighted Laplace equations on rough Riemannian manifolds with boundary

Our topological setting is a smooth compact manifold of dimension two or higher with smooth boundary. Although this underlying topological structure is smooth, the Riemannian metric tensor is only assumed to be bounded and measurable. This is known as a rough Riemannian manifold. For a large class of boundary conditions we demonstrate a Weyl law for the asymptotics of the eigenvalues of the Laplacian associated to a rough metric. Moreover, we obtain eigenvalue asymptotics for weighted Laplace equations associated to a rough metric. Of particular novelty is that the weight function is not assumed to be of fixed sign, and thus the eigenvalues may be both positive and negative. Key ingredients in the proofs were demonstrated by Birman and Solomjak nearly fifty years ago in their seminal work on eigenvalue asymptotics. In addition to determining the eigenvalue asymptotics in the rough Riemannian manifold setting for weighted Laplace equations, we also wish to promote their achievements which may have further applications to modern problems

Ellipro scores of donor epitope specific HLA antibodies are not associated with kidney graft survival

In kidney transplantation, donor HLA antibodies are a risk factor for graft loss. Accessibility of donor eplets for HLA antibodies is predicted by the ElliPro score. The clinical usefulness of those scores in relation to transplant outcome is unknown. In a large Dutch kidney transplant cohort, Ellipro scores of pretransplant donor antibodies that can be assigned to known eplets (donor epitope specific HLA antibodies [DESAs]) were compared between early graft failure and long surviving deceased donor transplants. We did not observe a significant Ellipro score difference between the two cohorts, nor significant differences in graft survival between transplants with DESAs having high versus low total Ellipro scores. We conclude that Ellipro scores cannot be used to identify DESAs associated with early versus late kidney graft loss in deceased donor transplants.</p

Determination of the clinical relevance of donor epitope-specific HLA-antibodies in kidney transplantation

In kidney transplantation, survival rates are still partly impaired due to the deleterious effects of donor specific HLA antibodies (DSA). However, not all luminex-defined DSA appear to be clinically relevant. Further analysis of DSA recognizing polymorphic amino acid configurations, called eplets or functional epitopes, might improve the discrimination between clinically relevant vs. irrelevant HLA antibodies. To evaluate which donor epitope-specific HLA antibodies (DESAs) are clinically important in kidney graft survival, relevant and irrelevant DESAs were discerned in a Dutch cohort of 4690 patients using Kaplan–Meier analysis and tested in a cox proportional hazard (CPH) model including nonimmunological variables. Pre-transplant DESAs were detected in 439 patients (9.4%). The presence of certain clinically relevant DESAs was significantly associated with increased risk on graft loss in deceased donor transplantations (p &lt; 0.0001). The antibodies recognized six epitopes of HLA Class I, 3 of HLA-DR, and 1 of HLA-DQ, and most antibodies were directed to HLA-B (47%). Fifty-three patients (69.7%) had DESA against one donor epitope (range 1–5). Long-term graft survival rate in patients with clinically relevant DESA was 32%, rendering DESA a superior parameter to classical DSA (60%). In the CPH model, the hazard ratio (95% CI) of clinically relevant DESAs was 2.45 (1.84–3.25) in deceased donation, and 2.22 (1.25–3.95) in living donation. In conclusion, the developed model shows the deleterious effect of clinically relevant DESAs on graft outcome which outperformed traditional DSA-based risk analysis on antigen level.</p

Ellipro scores of donor epitope specific HLA antibodies are not associated with kidney graft survival

In kidney transplantation, donor HLA antibodies are a risk factor for graft loss. Accessibility of donor eplets for HLA antibodies is predicted by the ElliPro score. The clinical usefulness of those scores in relation to transplant outcome is unknown. In a large Dutch kidney transplant cohort, Ellipro scores of pretransplant donor antibodies that can be assigned to known eplets (donor epitope specific HLA antibodies [DESAs]) were compared between early graft failure and long surviving deceased donor transplants. We did not observe a significant Ellipro score difference between the two cohorts, nor significant differences in graft survival between transplants with DESAs having high versus low total Ellipro scores. We conclude that Ellipro scores cannot be used to identify DESAs associated with early versus late kidney graft loss in deceased donor transplants

Hyperexpression of the granzyme B inhibitor PI-9 in human renal allografts: A potential mechanism for stable renal function in patients with subclinical rejection

Hyperexpression of the granzyme B inhibitor PI-9 in human renal allografts: A potential mechanism for stable renal function in patients with subclinical rejection.BackgroundGranzyme B–positive T lymphocytes infiltrate renal allografts during acute cellular rejection and cause graft injury by inducing apoptosis of tubular cells. Protease inhibitor 9 (PI-9), an intracellular serpin that inhibits granzyme B, is known to protect cells from the action of cytotoxic T lymphocytes.MethodsExpression of granzyme B and PI-9 in transplant biopsies from patients with acute cellular rejection (N = 18), subclinical rejection showing a mononuclear cell infiltrate without deterioration of renal function (N = 15), or stable transplant function (N = 13) were studied. Immunohistochemical stainings were analyzed and scored semiquantitatively by two independent observers who were not aware of clinical results.ResultsGranzyme B was expressed by mononuclear cells in all biopsies with cellular infiltrates. PI-9 was diffusely expressed by tubular cells in the allografts of all patients with subclinical rejection. In contrast, PI-9 expression was only focally in the patients with clinical rejection or without rejection. Although no difference was observed in granzyme B levels between acute and subclinical rejection, in subclinical rejection tubular epithelial cells showed significantly stronger expression of PI-9 than in acute rejection (P = 0.011).ConclusionThese data suggest that a high expression of PI-9 by tubular epithelial cells can serve as one of the factors protecting renal allografts from rejection in spite of the presence of inflammatory cell infiltrates

Serum neopterin/creatinine values correlate with severity of symptoms caused by cytomegalovirus infection in renal transplant recipients

Serum neopterin/creatinine ratios were longitudinally measured in 86 renal transplant recipients from the day before transplantation until 4 months after transplantation, and the relationship to the clinical symptoms of cytomegalovirus (CMV) infection was studied. Infection with cytomegalovirus occurred in 23 patients, 11 cases of which were due to primary infection. Symptoms caused by CMV infection were more severe in male patients, in patients who had received prior antirejection treatment, and in patients with primary CMV infection. The measurement of serum neopterin/creatinine ratios proved to be a marker for the severity of symptoms caused by CMV infection, as peak values were significantly higher in eight patients with CMV disease than in patients with no or only mild symptoms of CMV infection (P<0.05). Moreover, in seven out of eight cases of CMV disease, serum neopterin/creatinine ratios started to rise up to 2 weeks before CMV infection was proven by serology

Clinicopathological characteristics of T-cell non-Hodgkin lymphoma arising in patients with immunodeficiencies: a single-center case series of 25 patients and a review of the literature

Whereas for B cell lymphomas it is known that they occur more frequently in immunocompromised patients, such a relation has thus far not been clearly established for T cell lymphomas. Of 251 patients that were diagnosed with a T cell non-Hodgkin lymphoma in our center between 1999 and 2014, at least 25 were identified in immunocompromised patients. Here, we retrospectively analysed the clinical and pathological characteristics of these 25 cases. In addition, we searched the literature and present an overview of 605 previously published cases. The actual number of patients with B cell chronic lymphocytic leukemia and patients on immunosuppressive drugs for inflammatory bowel disease or rheumatoid arthritis in the total cohort of 251 patients diagnosed with T cell non-Hodgkin lymphoma was much higher than the number of patients expected to have these diseases in this cohort based on their prevalence in the general population. This, together with the large number of additional cases found in the literature, suggests that the risk of developing T cell non-Hodgkin lymphoma is increased in immunocompromised patients. Compared to T cell non-Hodgkin lymphoma in the general population these lymphomas are more often located extranodally, present at a younger age and appear to have a poor outcome. The observations made in this study should raise awareness of the possible development of T cell non-Hodgkin lymphoma in immunodeficient patients and challenge the prolonged use of immunosuppressive drugs in patients who are in clinical remission of their autoimmune diseas