Background. We investigated the influence of killer cell immunoglobulin-like receptor (KIR) genes, based on the genotypes of inhibitory or activating KIR, in stem cell recipients with acute myelogenous leukemia and their human leukocyte antigen-matched sibling donors on acute graft-versus host disease (GVHD) after hematopoietic stem cell transplantation. Methods. We studied 53 consecutive donor–recipient pairs to determine the impact of KIR genotypes and their bidirectional KIR interactions. Results. All activating KIR genes in donors were important factors for determining outcome in a manner distinctive for each gene studied. Specifically, the 2DS2 gene and the 2DS4*003 allele were closely correlated with acute GVHD. The 2DS1 gene was associated with a better long-term survival, even if present only in the donor and not the recipient. The 2DS3–2DS5 dual genes were more often involved in a variety of transplant-related complications. Conclusions. In conclusion, these factors may help predict transplant outcomes and aid in our understanding of immunogenetic specificity.

An infection after allogeneic stem cell transplantation (SCT) can affect the activity of immune cells and increase the level of proinflammatory cytokines. Further, a post‐SCT infection may influence the milieu of the graft‐versus‐leukemia (GVL) effect and graft‐versus‐host disease (GVHD). We performed a retrospective study of patients with acute leukemia who had undergone allogeneic SCT using the same preparative regimens and bone marrow as the stem cell source to determine if early post‐transplant infection was associated with the risk of leukemic relapse and GVHD. The analysis revealed that patients who had a febrile infection (FI) before post‐transplant day 21 (FI group) had a lower actuarial probability of leukemic relapse (P < 0.001) and a higher relapse‐free survival rate (P = 0.012) than those patients who did not have a FI before post‐transplant day 21 (non‐FI group). The experience of early post‐transplant FI (HR = 0.316; 95% CI = 0.174–0.575; P < 0.001), together with the presence of chronic GVHD and high risk cytogenetics, were independent predictive factors for post‐transplant leukemic relapse. The FI group had a trend towards a higher lymphocyte count on post‐transplant day 21 than the non‐FI group (P = 0.063), despite the delayed recovery of the platelet count and a trend towards delayed recovery of the neutrophil count. These findings suggest that a change in the immunologic network by infectious diseases in the early post‐transplant period favors the milieu of the GVL effect. The specific immunologic change during FI, which can potentiate the GVL effect, remains to be determined. Am. J. Hematol., 2008.

Lymphoma is one of the most common cancers worldwide, categorized into Hodgkin lymphoma and non-Hodgkin lymphoma. ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG PET) has become an essential imaging tool for evaluating patients with lymphoma in terms of initial diagnosis, staging, prognosis, and treatment response assessment. Recent advancements in imaging technology and methodologies, along with the development of artificial intelligence, have revolutionized the evaluation of complex imaging data, enhancing the diagnostic and predictive power of PET in lymphoma. However, FDG is not cancer-specific, but it primarily reflects glucose metabolism, which has prompted the investigation of alternative PET tracers to address this limitation. Novel PET radiotracers, such as fibroblast activation protein inhibitors targeting the tumor microenvironment, have recently shown promising results in evaluating various malignancies compared to FDG PET. Furthermore, with the rapid advancements in immunotherapy and the favorable imaging properties of ⁸⁹Zr, immunoPET has emerged as a promising modality, offering insights into the functional and molecular status of the immune system. ImmunoPET can also facilitate the development of new antibody therapeutics and radioimmunotherapy by providing pharmacokinetic and pharmacodynamic data. This review provides comprehensive insights into the current clinical applications of FDG PET in lymphoma, while also exploring novel PET imaging radiotracers beyond FDG, discussing their mechanisms of action and potential impact on patient management.