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Background: Treatment with antithymocyte globulin (ATG) is a well-recognized risk factor for the development of post-transplant lymphoproliferative disorders (PTLD) after solid organ transplantation, but it is unknown how its use affects overall survival after PTLD. Methods: A total of 114 patients with PTLD and available data on immunosuppressive regimen were included from a nation-wide case series of solid organ transplant recipients in Sweden. Prior use of ATG was correlated to clinical features, PTLD subtype, and survival. Results: A total of 47 (41%) patients had received ATG prior to the diagnosis of PTLD. The ATG-treated patients were more likely to be recipients of hearts or lungs, and less likely of kidneys ( p  < 0.01). They had experienced more acute rejections ( p  = 0.02). The PTLDs arose earlier, median 2.0 vs. 6.6 years post-transplant ( p  = 0.002) and were more often situated in the allograft (32% vs. 7%, p  < 0.001) in patients with prior ATG vs. no ATG treatment. The PTLDs in the ATG group were more often Epstein-Barr virus-positive (80% vs. 40%, p  < 0.001). There were more polymorphic PTLDs (17% vs. 1.5%, p  = 0.004) and less T-cell PTLDs (4% vs. 19%, p  = 0.02) in the ATG group than in the no ATG group. Diffuse large B-cell lymphoma was equally common in patients with and without prior ATG therapy, but the non-germinal center subtype was more frequent in the ATG group ( p  = 0.001). In an adjusted Cox proportional hazards regression model, prior ATG treatment and better performance status were associated with superior overall survival, whereas older age, T-cell subtype of PTLD, presence of B symptoms, and elevated lactate dehydrogenase were associated with inferior overall survival. Patients receiving ATG solely as rejection therapy had superior overall survival compared with those receiving ATG as induction therapy or both ( p  = 0.03). Conclusions: ATG therapy, especially rejection therapy, prior to PTLD development is an independent prognostic factor for superior overall survival after PTLD diagnosis.

Background: Post-transplant lymphoproliferative disorder (PTLD) is a rare but life-threatening complication of transplantation. For refractory and relapsed PTLD new therapies are needed, such as the antibody-drug conjugate brentuximab vedotin that targets CD30. There is limited knowledge of CD30 expression in various subtypes of PTLD and its correlation to clinicopathological features. Therefore, we studied the expression of CD30 in PTLD following solid organ transplantation and correlated CD30 expression to PTLD subtype, Epstein-Barr virus (EBV)-status, intratumoral regulatory T-cells (Tregs), clinical features, and outcome. Methods: We included 50 cases of PTLD from a nation-wide study of PTLDs following solid organ transplantation in Sweden. The tumor biopsies were reevaluated, and clinical data were collected. CD30 expression on tumor cells was analyzed by immunohistochemistry with the clone Ber-H2. Thirty-one cases were stained with clone 236 A/E7 for detection of forkhead box protein 3 (FoxP3, a Treg biomarker). Results: The case series consisted of 6% polymorphic, 88% monomorphic, and 6% Hodgkin lymphoma-like PTLDs and 53% of the cases were EBV+. Overall, 70% (35/50) of the PTLDs were CD30+ (≥1% CD30+ tumor cells) and 30% (15/50) were CD30-. All polymorphic PTLDs ( n  = 3) and Hodgkin lymphomas ( n  = 3), 88% (14/16) of non-germinal center type of diffuse large B-cell lymphoma (DLBCL), and 75% (9/12) of T-cell PTLDs were CD30+ whereas all germinal center-type of DLBCL ( n  = 5) and Burkitt type PTLD ( n  = 2) were CD30-. CD30+ PTLD tended to be EBV+ more frequently ( p  = .07) and occurred earlier posttransplant (2.1 vs. 8.2 years, p  = .01) than CD30- PTLD. Type of transplant and localization of the tumor did not differ between the groups except that CNS engagement was more common in CD30- PTLD ( p  = .02). CD30-status was not associated with presence of intratumoral Tregs or overall survival. Conclusion: Expression of CD30 varied with PTLD subtype. There was no association between CD30 and survival, regardless of subtype.

We studied the expression of programed death 1 (PD-1) receptor and its ligands (PD-L1/-L2) by immunohistochemistry and its association with clinicopathological features in 81 posttransplant lymphoproliferative disorders (PTLDs) following solid organ transplantation. Overall, 67% (54/81) of the PTLDs were positive in any of the three immunostainings. PD-1 was detected on tumor-infiltrating cells in 41% (33/81) of the PTLDs. PD-L1 was expressed on ≥5% of the tumor cells in 50% (40/80) and PD-L2 in 32% (23/72) of the PTLDs. All Burkitt lymphomas were PD-L1 negative. Expression of PD-L1 tended to be associated with non-germinal center-type of diffuse large B-cell lymphoma (63% vs. 33% in GC-type, p = .14) and latent membrane protein-1+ PTLD (76% vs. 44% in LPM1-, p = .09). Heart recipients had more frequent PTLDs with PD-1+ microenvironment (p = .01). The frequent expression of PD-1 or -L1/-L2 in PTLD warrants further clinical evaluation of the efficacy and safety of PD-(L)1 inhibitors for refractory PTLD.

Background: The infiltration of regulatory T cells (Tregs) in lymphomas is associated with better prognosis for some types of lymphomas, but knowledge of their role in posttransplant lymphoproliferative disorders (PTLDs) is limited. We therefore investigated the association between the expression of the Treg marker forkhead box protein 3 (FoxP3) in biopsies of PTLDs and survival, PTLD subtype, and clinical characteristics., Methods: Seventy-four cases of PTLD after solid organ transplantation with sufficient material for further analysis were included from a population-based study of PTLDs in Sweden. The PTLD biopsies were reevaluated and stained with the 236A/E7 antibody to detect FoxP3 in lymphoma tissue. Detailed clinical data were collected retrospectively from medical records., Results: Based on a cutoff level of 29 FoxP3 cells per mm, most (80%) of the PTLDs were FoxP3. Forty-seven of 74 PTLDs displayed no FoxP3 cells at all. The frequency of FoxP3 cells did not influence median overall survival. The FoxP3 PTLDs were more frequently of T-cell phenotype (P = 0.04), located at the graft (P = 0.03), occurred earlier after transplantation (P = 0.04), were more likely to develop in lung recipients (P = 0.04), and in patients that had received anti-T-cell globulin as induction therapy (P = 0.02). The FoxP3 PTLDs were associated with hepatitis C seropositivity (P = 0.03). In multivariate analysis, B-cell PTLD and hepatitis C infection were independent predictors of FoxP3 positivity., Conclusion: Our findings suggest that intratumoral FoxP3 Tregs do not influence survival in patients with PTLD. FoxP3 Tregs are rare in PTLD, possibly because of heavy immunosuppression.

Background. Epstein-Barr virus (EBV) plays a major role in the development of post-transplant lymphoproliferative disorder (PTLD), but there is an increasing awareness of EBV-negative PTLD. The clinical presentation of EBV-negative PTLD has not been as well characterised as EBV-positive cases. Further, there is limited knowledge on the clinical importance of diffuse large B-cell lymphoma (DLBCL) cell of origin subtype post-transplant. Materials and methods. We studied the role of EBV, hepatitis C (HCV) and DLBCL subtype in clinical presentation and survival in 135 post-transplant lymphomas diagnosed 1980-2006 in a population-based cohort of 10 010 Swedish solid organ transplant recipients. The lymphomas were re-evaluated according to WHO 2008, examined for EBV, and clinical data were collected from medical records. Results. Lymphoma incidence rate was 159/100 000 person-years and is also reported by lymphoma subtype. EBV-negative lymphomas constituted 48% and were associated with HCV infection (p = 0.02), bone marrow involvement (p < 0.001), and T-cell phenotype (p = 0.002). Among DLBCL, 78% were of non-germinal centre subtype, which was associated with EBV-positivity (69%, p = 0.001), early occurrence (p = 0.03), heart/liver/lung/pancreas recipients (p = 0.02), anti-T-cell globulin (p = 0.001), and tacrolimus treatment (p = 0.02). DLBCL subtypes had similar overall survival. Five-year overall survival was 42% in all treated patients. Independent poor prognostic factors were older age, B symptoms, ECOG 2-4, kidney/pancreas/heart recipients, T-cell lymphoma, and HCV-infection. Conclusions. With long follow-up, a large part of PTLD is EBV-negative, due to a high proportion of T-cell lymphomas and low of polymorphic PTLD. EBV-negative PTLD have a different clinical presentation. HCV may play an aetiological role in late-onset PTLD and was revealed as a new prognostic factor for inferior survival that needs to be confirmed in larger studies. The heavier immunosuppression in non-kidney transplantations seems to play a role in the development of non-germinal centre DLBCL. DLBCL cell of origin subtype lacks prognostic importance in the transplant setting. [ABSTRACT FROM AUTHOR]

Background: Diffusion-weighted imaging (DWI) has become increasingly valuable in lymph node imaging, yet the clinical utility of this technique in the staging of lymphoma has not been established. Purpose: To compare whole-body DWI with FDG-PET/CT in the staging of lymphoma patients. Material and Methods: Thirty-one patients, eight with Hodgkin lymphoma (HL) and 23 with non-Hodgkin's lymphoma (18 aggressive and five indolent) underwent both whole-body DWI, whole-body MRI (T1W and T2W-STIR) and FDG-PET/CT. Lesions on whole-body DWI were only considered positive if they correlated with lesions on T1W and T2W-STIR images. The staging given by each technique was compared, according to the Ann Arbor staging system. Differences in staging were solved using biopsy results, and clinical and CT follow-ups as standard of reference. Results: The staging was the same for DWI and FDG-PET/CT in 28 (90.3%) patients and different in three (9.7%). Of the 28 patients with the same staging, 11 had stage IV in both techniques and 17 had stages 0-III. No HL or aggressive non-Hodgkin's lymphoma patients had different staging. Three indolent small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL) lymphoma had higher staging with DWI when compared with FDG-PET/CT. One small subcutaneous breast lymphoma was not seen but all other extranodal sites were detected by both techniques. Conclusion: Whole-body DWI is a promising technique for staging of both (aggressive and indolent) non-Hodgkin's lymphoma and HL. [ABSTRACT FROM AUTHOR]

Previous studies indicate that the inflammatory response in diffuse large B-cell lymphomas (DLBCL) is important for the clinical outcome. Mast cells are key regulators in this response; we investigated whether the number of tryptase-positive mast cells is correlated with clinical outcome. Patients with many mast cells had a significantly better event-free survival (EFS) compared to those with few mast cells ( P < 0·03 in both germinal centre (GC) and non-GC DLBCL. This supports the idea that the infiltration of mast cells is a reflection of the host inflammatory response and is related to a favourable outcome. [ABSTRACT FROM AUTHOR]

The etiology of classical Hodgkin lymphoma (cHL) is largely unknown. High serum CD30-levels are associated with increased risk of cHL. Epstein-Barr virus (EBV) is detectable in the tumor cells in 1/3 of cHL cases in the Western world. The PD-1 pathway (T-cell inflamed immune response) might contribute to the pathogenesis by enabling pre-malignant CD30+ or EBV + cells to evade immune surveillance. We aimed to investigate if high infiltrations of CD30+, PD-1+, PD-L1+ and EBV + cells in benign lymph nodes from patients that later develop cHL (cases) (n = 15) were associated with risk of cHL compared to controls (n = 45) with benign lymph nodes from patients that did not develop cHL. Pathology registries including 3500 cH L patients were screened. Lymph nodes were stained with immunohistochemistry and in situ hybridization and the risk for cHL calculated with logistic regression. High CD30-expression by B- and T-cells was associated with a decreased risk of cHL [(OR = 0.10, 95 % CI:0.03-0.39) and (OR = 0.13, 95 % CI:0.01-0.71), respectively], which remained significant for CD30 + B-cells (OR = 0.15, 95 % CI:0.03-0.60) in multivariate analyses. Amount of PD-1+, PD-L1+ and EBV + cells were not statistically significantly associated with risk of cHL. However, the amount of PD-L1+ leukocytes tended to be higher in cases later developing cHL (OR = 2.84, 95 % CI:0.61-12.61). High proportions of potential precursors to cHL, i.e. CD30 + B-cells in benign lymph nodes are not associated with an increased risk of cHL, while a tendency for a T-cell inflamed immune response, i.e. abundant PD-L1+ cells, was observed in biopsies taken prior to the cHL diagnosis. [ABSTRACT FROM AUTHOR]