Paweł Poznański

Kidney transplantation is the optimal treatment for end-stage renal disease, yet long-term graft survival remains limited by allograft rejection. While T and B cells and donor-specific antibodies (DSA) have been the main focus, accumulating evidence indicates that natural killer (NK) cells play a significant dual role in both graft injury and immune adaptation, including in DSA-negative rejection. This narrative review summarizes current knowledge on the dual role of NK cells in kidney transplantation, with emphasis on antibody-independent mechanisms, adaptive NK-cell subsets, and their potential as biomarkers of graft outcome. NK cells are highly heterogeneous, consisting of CD56 ^bright and CD56 ^dim CD16 subsets. Cytomegalovirus infection promotes expansion of adaptive NKG2C ⁺ CD57 ⁺ cells with memory-like features. In rejection, NK cells act through both antibody-dependent cellular cytotoxicity and antibody-inde-pendent pathways, such as “missing-self” recognition via killer immunoglobulin-like receptors (KIR)/human leukocyte antigen (HLA) mismatch and release of the killer-specific secretory protein of 37 kDa (Ksp37). Specific NK subsets are associated with microvascular inflammation and graft loss even in the absence of DSA. In contrast, NK cells support tolerance by killing donor dendritic cells and activated T cells, producing interleukin (IL)-10 and transforming growth factor-β (TGF-β), and undergoing reeducation, gradually shifting from a cytotoxic to a regulatory phenotype. NK cells exert a dual, often opposing role in kidney transplantation, mediating both allograft injury and immune tolerance. Better understanding of their plasticity may enable new biomarkers and NK-targeted therapies to improve long-term graft survival.

Autoimmune nephrological and rheumatological diseases involve macrophage-driven inflammation, yet disease activity is often assessed using invasive or non-specific measures. Soluble CD163 (sCD163), released from activated monocytes and macrophages, is emerging as a biomarker of macrophage-mediated inflammation in these conditions. This narrative review summarizes current evidence on the diagnostic, prognostic, and disease-monitoring potential of sCD163 measured in blood, urine, and synovial fluid in autoimmune nephrological and rheumatological diseases. This review is based on a narrative analysis of selected publications investigating the clinical utility of sCD163 in autoimmune kidney and rheumatic diseases, with emphasis on correlations with disease activity, histopathological findings, and clinical outcomes. Urinary sCD163 shows excellent diagnostic accuracy for active lupus nephritis (area under the receiver operating characteristic [AUROC] 0.89–0.998), correlates with histological activity index (but not chronicity), and distinguishes ongoing inflammation from chronic damage during treatment. In IgA nephropathy, it predicts remission failure and greater benefit from corticosteroids. In ANCA-associated vasculitis, it identifies active renal involvement (AUROC 0.95 in multicenter cohorts). In rheumatoid arthritis (RA), serum sCD163 correlates with early disease activity, predicts radiographic progression, and detects subclinical macrophage activation in remission. In spondylarthritis, synovial fluid sCD163 reflects a disease-specific M2-polarized macrophage phenotype distinct from RA. Utility is compartmentalized: urinary levels indicate intrarenal macrophage activation, synovial fluid local joint inflammation, and serum systemic activation. sCD163 is a promising macrophage-specific biomarker across autoimmune diseases, but its compartmentalized nature requires context-specific measurement. Before clinical implementation, assay standardization, multicenter validation, and interventional trials showing the benefit of sCD163-guided management are needed.

Background/Objectives: The goal of reconstructive hand surgery is to achieve both functional and aesthetic restoration. The primary aim of this study is to perform a detailed, practice-oriented evaluation of perforator-based and local flaps for soft-tissue reconstruction of the hand and digits, focusing specifically on their functional reliability, anatomical consistency, complication profile, and aesthetic integration in a real-world, high-complexity referral population. Methods: This retrospective single-center study included 37 patients with soft tissue defects of the hand that required flap coverage between September 2021 and September 2024. The study assessed patient demographics, defect characteristics, flap selection, surgical techniques, and outcomes including satisfactory soft tissue coverage, functional results and occurrence of complications. Various perforator flaps were analyzed, including the dorsal metacarpal artery flap, reverse radial forearm flap, reverse posterior interosseous artery flap, reverse homodigital and heterodigital island flaps, and the thenar flap. Results: Satisfactory soft tissue coverage was achieved in 35 out of 37 patients. One case involved partial distal flap necrosis, and another presented with Foucher flap failure. The remaining flaps demonstrated stable integration, preserved perfusion, and durable soft-tissue coverage with satisfactory contour and pliability. Functional outcomes were favorable, with restoration of joint mobility and absence of secondary deformities. Conclusions: This study supports the continued use of perforator and local flaps in upper extremity reconstruction, emphasizing the need for individualized planning to optimize the outcomes.

Background: There is a great deal of knowledge regarding the development of polyomavirus-associated nephropathy and polyomavirus-associated hemorrhagic cystitis in transplant recipients with active BKPyV infection. However, recent studies have revealed a potential association between BKPyV reactivation and certain malignancies, including transitional cell carcinoma, malignant melanoma, colorectal cancer, and prostate cancer. This study aimed to identify a potential link between BKPyV infection and oncogenic transformation in kidney transplant recipients. Methods: Presentation of a case series of kidney transplant recipients diagnosed with polyomavirus-associated nephropathy who developed neoplasms after transplantation. Results: Positive immunohistochemical reactions confirmed the presence of polyomavirus large T antigen in tissue samples from all three patients’ cancers. Furthermore, a case of chromophobe renal cell carcinoma presenting BKPyV proteins in cancer cells was observed for the first time in the literature. Conclusions: BKPyV reactivation was found to be associated with the development of both urothelial cancer, which originates directly from the BKPyV-infected site, and colorectal cancer.

Background/Objectives: The risk of post-transplantation lymphoproliferative disorder (PTLD) varies according to the type of transplanted organ. To investigate the factors contributing to PTLD development and treatment outcomes, we established a multicenter registry that included patients diagnosed with PTLD within a population of 13,263 kidney, liver, and lung transplant recipients (KTRs, LTRs, and LngTRs, respectively), observed in a period between 2000 and 2023. Methods: The chi-squared test was used to analyze differences in group composition. Univariate and multivariate Cox regression were applied to determine the impact of factors upon PTLD onset and patient survival. Results: Our registry included 58 out of 9432 KTRs, 40 out of 3500 LTRs, and 5 out of 331 LngTRs. The median time to PTLD onset was significantly longer among KTRs (117 months post-transplant) than among LTRs (49 months, p < 0.001) and LngTRs (5 months, p < 0.001). LTRs treated with tacrolimus developed PTLD later compared to LTRs treated with cyclosporin (p = 0.042). In multivariate analysis, older age at first transplantation correlated with earlier disease development in SOTRs (HR = 1.03, p = 0.006) and KTRs (HR = 1.04, p = 0.003). Older age at first transplantation was also associated with worse survival among KTRs (p = 0.045). Conclusions: We identified clear differences in the factors affecting PTLD onset and survival between KTRs and LTRs. Organ-specific analyses are needed to improve our understanding of PTLD risk factors, treatment choices, and clinical outcomes.

DOI: 10.20452/pamw.16816, Published online: August 01, 2024, Authors: Julia Janeczko, Agata Góral, Paweł Poznański, Aleksandra Zgryźniak, Dorota Kamińska, Magdalena Krajewska

Background: The ability of hemoglobin to bind and dissociate oxygen is crucial in delivering oxygen to tissues and is influenced by a range of physiological states, compensatory mechanisms, and pathological conditions. This may be illustrated by the oxyhemoglobin dissociation curve (ODC). The key parameter for evaluating the oxygen affinity to hemoglobin is p50. The aim of this study was to evaluate the impact of hemodialysis on p50 in a group of patients with chronic kidney disease (CKD). An additional goal was to assess the correlation between p50 and the parameters of erythropoiesis, point-of-care testing (POCT), and other laboratory parameters. Methods: One hundred and eighty patients (106 male, 74 female), mean age 62.5 ± 17 years, with CKD stage G4 and G5 were enrolled in this cross-sectional study. Patients were divided into two groups, including 65 hemodialysis (HD) patients and 115 patients not receiving dialysis (non-HD). During the standard procedure of arteriovenous fistula creation, blood samples from the artery (A) and the vein (V) were taken for POCT. The causes of CKD, as well as demographic and comorbidity data, were obtained from medical records and direct interviews. Results: The weekly dose of erythropoietin was higher in HD patients than in non-HD patients (4914 ± 2253 UI vs. 403 ± 798 UI, p < 0.01), but hemoglobin levels did not differ between these groups. In the group of non-HD patients, more advanced metabolic acidosis (MA) was found, compared to the group with HD. In arterial and venosus blood samples, the non-HD group had significantly lower pH, pCO₂ and HCO₃⁻. This group had a higher proportion of individuals with MA with HCO₃⁻ < 22 mmol/L (42% vs. 24%, p < 0.01). The absolute difference of p50 in arterial and venous blood was determined using the formula Δp50 = (p50-A) − (p50-V). Δp50 was significantly higher in the HD group in comparison to non-HD (0.08 ± 2.05 mmHg vs. −0.66 ± 1.93 mmHg, p = 0,02). There was a negative correlation between pH and the p50 value in arterial (pH-A vs. p50-A, r = −0.56, p < 0.01) and venous blood (pH-V vs. p50-V, r = −0.45, p < 0.01). In non-HD patients, hemoglobin levels correlated negatively with p50 (r = −0.29, p < 0.01), whereas no significant relation was found in HD patients. Conclusions: The ODC in pre-dialysis CKD (non-HD) patients is shifted to the right due to MA, and this is an additional factor influencing erythropoiesis. Hemodialysis restores the natural differences in hemoglobin’s dissociation characteristics in the arterial and venous circulation.

DOI: 10.20452/pamw.16702, Published online: March 15, 2024, Authors: Zuzanna Dybko, Paweł Poznański, Oktawia Mazanowska, Maciej Guziński, Magdalena Krajewska, Dorota Kamińska

Aim of the study: Rapid emergence and transmission of SARS-CoV-2 significantly impacted mental health. Restrictions, lockdowns and quarantines issued during the wait for vaccines resulted in additional psychological distress in most populations. We aim to describe the impact of perceived stress related to the pandemic and sociodemographic determinants on sleep disturbances in the population of patients with chronic medical conditions, such as psoriasis, kidney transplant recipients and undergoing dialysis.Subject or material and methods: During the cross-sectional survey conducted between May and October 2020, we enrolled 270 patients with three different chronic medical conditions. Study sample was examined regarding the reported sleep complaints (Insomnia Severity Index), occurrence of psychopathological symptoms (General Health Questionnaire 28) and their perceived levels of stress related to pandemic (Perceived Stress Scale).Results: We observed 25,2% prevalence of ISI scores indicative of clinical insomnia in the group of chronically-ill patients during the first phase of the pandemic. ISI scores were found to be strongly correlated with GHQ28 and moderately correlated with PSS-10 scores. The profiles of reported complaints varied significantly between groups.Discussion: There are varied outcomes related to sleep disturbances measured with ISI in the general population depending on the country and phase of pandemic with most of them ranging from 11.5 to 20% .Conclusions: Findings of our study suggest that population of patients with chronic conditions, with special emphasis on those who have a simultaneous history of psychiatric or psychological treatment, requires additional attention in order to objectivize and maintain sleep disorders during occurrence of severe stress conditions such as the COVID-19 pandemic.

DOI: 10.20452/pamw.16472, Published online: March 30, 2023, Authors: Aleksandra Szczygieł, Katarzyna Logoń, Paweł Poznański, Magdalena Koszewicz, Magdalena Krajewska, Dorota Kamińska