We report the case of a 60-year-old man who initially presented in October 2021 with a history of recurrent itchy skin lesions across exposed areas of his body such as the neck and extremities. As per history and clinical examination, the lesions were initially interpreted as an insect bite reaction for which the patient was provided with symptomatic treatment. Despite the treatment, the patient continued to experience recurrent skin lesions. Histopathologic exam of a skin biopsy showed eosinophil-rich superficial and deep inflammatory infiltrates which supported the diagnosis of a cutaneous reaction to an insect bite or another hypersensitivity-type reaction which further made the diagnosis challenging. In 2024, he developed systemic symptoms such as dizziness, vomiting, and generalized lymphadenopathy. Laboratory tests revealed significant leukocytosis with persistent lymphocytosis, mild anemia, and thrombocytopenia. A peripheral smear was done and showed mature lymphocytosis with smudge cells. Flow cytometry identified a clonal B-cell population expressing CD5, CD23, CD200, and lambda light-chain reaction, supporting a diagnosis of chronic lymphocytic leukemia. Positron emission tomography-computed tomography (PET-CT) demonstrated hypermetabolic lymphadenopathy above and below the diaphragm and hepatosplenomegaly. Cutaneous manifestations resembling different benign dermatologic conditions, such as an insect bite reaction, may rarely precede systemic symptoms of an underlying hematologic malignancy. This case emphasizes the significance of reassessment and follow-up in patients with recurrent and evolving dermatological findings.

As the frequency and significance of bone marrow (BM) infiltration in enzootic bovine leukosis (EBL) remain unclear, this study evaluated BM involvement and its relationship with peripheral blood (PB) findings in 11 cattle with EBL using PB evaluation, and BM aspiration cytology. BM infiltration was identified in 5 of 11 (45%) EBL cases based on BM smears. All EBL cases showed circulating atypical lymphocytes, although BM infiltration was not consistently present. Two cases with extreme PB lymphocytosis showed BM infiltration. Cytopenia was variably observed and was most severe in cases with extensive BM involvement. This study provides combined assessment of PB and BM changes in EBL cattle and suggests that such evaluation enables a more comprehensive characterization of hematological alterations.

Monoclonal gammopathy of undetermined significance (MGUS), monoclonal B-cell lymphocytosis (MBL), and clonal hematopoiesis (CH) of indeterminate potential represent highly prevalent, age-associated precursor states characterized by detectable serological, cellular, or genetic alterations in otherwise asymptomatic individuals. The advent of high-sensitivity technologies, including mass spectrometry, multiparametric flow cytometry, and next-generation sequencing, has revealed that these conditions are far more widespread than previously appreciated, yet only a minority of affected individuals progress to overt malignancies such as multiple myeloma, chronic lymphocytic leukemia, or myeloid neoplasms. Across these entities, a unifying paradigm is emerging in which malignant transformation is governed not simply by the presence of driver lesions, but by dynamic clonal evolution shaped by intrinsic fitness, temporal acquisition of alterations, and selective pressures imposed by the aging microenvironment. In CH, mutation-specific growth kinetics and inflammation-driven selection define both hematologic and systemic risks. In MBL, antigenic stimulation, immune dysfunction, and genetic complexity modulate progression to CLL. In MGUS, disease evolution reflects a gradual co-evolution between plasma cell clones and a progressively permissive niche. Aging-associated inflammation and tissue remodeling act as common denominators, fostering a competitive landscape that selectively advantages aberrant clones while suppressing normal hematopoiesis. In turn, these clones actively remodel their microenvironment, establishing feed-forward loops that sustain clonal expansion and malignant potential. Integrating insights across CH, MBL, and MGUS highlights shared biological principles and supports a shift toward "precision prevention" strategies aimed at intercepting high-risk trajectories while minimizing unnecessary surveillance in low-risk individuals.

A 70-year-old male with CLL presented with dengue fever complicated by AKI. A diagnostic challenge arose from overlapping features. Investigations showed leukocytosis, lymphocytosis, anemia, thrombocytopenia, positive Anti-Dengue IgM, and renal impairment. Managed with supportive care, ibrutinib, and monitoring, with improvement. At the 3-month follow-up, he remained stable, highlighting the importance of multidisciplinary management.

Aeromonas hydrophila is a major zoonotic bacterial pathogen responsible for haemorrhagic septicemia, substantial economic losses in aquaculture and increasing antimicrobial resistance among field isolates. It is also one of the main bacterial species associated with mortality outbreaks in pirapitinga, Piaractus brachypomus, culture in the Amazon region of Latin America. Therefore, this study evaluated the immunogenicity and protective efficacy of the first autogenous vaccine against A. hydrophila developed for P. brachypomus, formulated with or without a Montanide adjuvant. A total of 150 fish were vaccinated by intraperitoneal injection with a formalin-inactivated homologous bacterin and, at 35 days post-vaccination, challenged with a homologous strain of A. hydrophila at the median lethal dose (LD50). Following bacterial challenge, biological samples were collected at 24 h post-challenge, and survival was monitored for 15 days (50-day trial period). The vaccinated groups showed enhanced immune responses, characterized by increased ROS levels, lysozyme activity, agglutinating antibody titers and IgM levels, particularly in the fish vaccinated with the adjuvant. Haematological evaluation revealed lymphocytosis and, morphologically, lower lesion severity and preservation of renal architecture in vaccinated groups. In contrast, infected non-vaccinated fish exhibited leukopenia, tubular disorganization, intense mononuclear inflammatory infiltrates, glomerular alterations and lesions suggestive of tissue necrosis. These findings were reflected in enhanced protection following the bacterial challenge, with relative percent survival (RPS) values of 76.19% for fish vaccinated without the adjuvant and 85.71% for those vaccinated with the adjuvant. Overall, the autogenous vaccine was safe, immunogenic and provided effective protection against Aeromonas hydrophila infection in Piaractus brachypomus.

Early infancy represents a critical window of immune system maturation during which transient dysregulation may result in atypical inflammatory or autoimmune-like phenotypes. Distinguishing such self-limited processes from true systemic autoimmune disease remains a major clinical challenge. We report an infant presenting with prominent cutaneous manifestations, markedly elevated inflammatory markers, hypocomplementemia, and broad high-titer autoantibody positivity including antinuclear, anti-dsDNA, extractable nuclear antigen, and antineutrophil cytoplasmic antibodies. Despite a laboratory profile strongly suggestive of systemic autoimmune disease, the patient remained clinically stable without evidence of organ involvement, including renal, neurological, or cardiopulmonary systems. Immunophenotyping demonstrated lymphocytosis with expansion of CD19+ B cells, while T-cell subsets and natural killer cells remained within expected ranges. Interferon signature analysis was negative, and whole-exome sequencing did not identify a causative monogenic disorder. All immunological abnormalities resolved spontaneously without immunosuppressive therapy. During follow-up, the patient developed transient neutropenia and atopic dermatitis, both with a self-limited course. This case highlights a transient systemic immune phenotype characterized by expansion of the CD19+ B-cell compartment, broad humoral immune activation and complement consumption in early infancy, followed by complete restoration of immune homeostasis. Recognition of such self-limited immune dysregulation is essential to avoid unnecessary immunosuppressive therapy and provides insight into mechanisms of immune tolerance during early human development.

The tyrosine kinase inhibitor dasatinib is prescribed as a first-line treatment for Philadelphia chromosome-positive leukemias and is increasingly used in other clinical settings. While dasatinib is effective and generally well tolerated, patients often experience a transient lymphocytosis attributable to a dasatinib-induced spleen contraction and an acute mobilization of splenocytes, as we have recently demonstrated in murine models and human patients. In contrast, the impact of dasatinib on lymphocyte surveillance of other secondary lymphoid organs, such as peripheral lymph nodes (LNs), has remained unclear. Here, we report that while dasatinib treatment selectively disrupted in vitro chemotaxis of B but not T cells, it caused a substantial, transient reduction of the in vivo interstitial motility in both subsets. The broad in vivo inhibition of T and B cell motility correlated with dasatinib-induced vasoconstriction of blood vessels and increased hypoxia within LNs. Pharmacological inhibition of the contraction-promoting factor Rho-associated coiled-coil kinase (ROCK) reversed dasatinib-induced LN hypoxia and rescued CD8+ T cell motility. Last, dasatinib treatment delayed but did not inhibit dendritic cell-mediated CD8+ T cell activation and proliferation within LNs. Overall, our findings uncover a dasatinib-induced transient disruption of the local adaptive immune system, which is distinct from the previously observed spleen contraction. From a clinical point of view, the disruption-recovery cycle of physiological immune surveillance induced by daily dasatinib treatment does not appear to cause a substantial impairment of key pathways underpinning CD8+ T cell activation.

Increasing multiple anthelmintic resistance in Haemonchus contortus has been reported worldwide, highlighting the need for alternative strategies to mitigate the damage caused by this nematode. In this study, we developed and evaluated an immunotherapy protocol based on specific antibodies against the ES24 antigen of H. contortus. Purified and biologically active immunoglobulins were successfully produced through the immunization of sheep donors. The purified immunoglobulins were pooled, evaluated for specific anti-ES24 levels of IgG, IgM and IgA isotypes by indirect ELISA, presenting reduced larval infectivity in vitro. In vivo, immunotherapy-treated lambs showed reduced worm development and fecundity following experimental H. contortus infection. Immunotherapy administration also significantly reduced inflammatory responses, as demonstrated by lower peripheral monocyte counts and reduced neutrophilic infiltration in the abomasal lamina propria compared to untreated infected lambs. Furthermore, treated lambs exhibited enhanced innate and adaptive immune responses, characterized locally by increased expression of TLR4 and GAL11, and systemically by lymphocytosis, particularly in female lambs. Overall, the proposed immunotherapy protocol represents a promising immunotherapy to reduce the impact of haemonchosis on sheep production, targeting antigens with low probability of developing resistance.

A healthy 20-year-old woman presented with high fever and fatigue. Laboratory findings included normal complete blood counts and the absence of atypical lymphocytes. The patient had markedly elevated C-reactive protein, hyperferritinemia, and coagulation abnormalities consistent with disseminated intravascular coagulation, while imaging studies and extensive infectious and autoimmune workups were unremarkable. Serological testing and polymerase chain reaction confirmed a primary cytomegalovirus (CMV) infection. The administration of ganciclovir followed by corticosteroid therapy resulted in the improvement of the patient's clinical symptoms and laboratory findings. Clinicians should consider primary CMV infection in the differential diagnosis of severe coagulation abnormalities associated with a hyperinflammatory state, even in immunocompetent patients without atypical lymphocytosis.