Effect of antimetabolite regimen on cellular and humoral immune response to SARS-COV-2 vaccination in solid organ transplant recipients.

OBJECTIVE: Novel mRNA-based vaccines have been proven to be powerful tools in combating the global pandemic caused by SARS-CoV-2 protecting individuals, especially the immunocompromised, from COVID-19. Still, it remains largely unknown how solid organ transplant and different immunosuppressive medications affect development of vaccine-induced immunity. METHODS: In this work, we monitored humoral and cellular memory responses after mRNA SARS-CoV-2 two-doses and booster doses vaccination in cystic fibrosis lung transplanted patients (CFT) and compared them with both cystic fibrosis patients without lung transplant (CF) and with kidney transplant recipients (KT). In particular, we investigated the effects of immunosuppressive regimens on immune memory to SARS-CoV-2 after mRNA SARS-CoV-2 vaccine in transplanted patients. RESULTS: Our results showed that immunocompromised transplanted patients displayed a weak cellular and humoral memory to SARS-CoV-2 mRNA vaccination. In addition, obtained data clearly demonstrate that immunosuppressive therapy regimen including antimetabolites, further reduces patients' ability to respond to vaccination at both humoral and cell-mediated level. Notably, patient treated with antimetabolites showed a lower humoral and cellular response also after a booster dose vaccination. CONCLUSION: These results, even if obtained on a small patient's cohort, question whether immunocompromised patients need interventions to improve vaccine SARS-CoV-2 mRNA vaccine response such as additional jab or modulation of immunosuppressive therapy.

HPLC and flow cytometry combined approach for HbF analysis in fetomaternal haemorrhage evaluation.

Introduction: Recently, a flow cytometric (FC) based test has been developed for detection of circulating fetal cells to replace the less accurate and reproducible Kleihauer-Betke test.FC test is easier to perform, it can distinguish the origin of fetal cells, but it is expensive and available in highly specialized laboratories. We evaluated the introduction of high-performance liquid chromatography (HPLC) approach as initial screening to identify patients who need an additional FC test to better discriminate the nature of haemoglobin-F (HbF) positive cells. Methods: Blood samples from 130 pregnant women suspected to have fetomaternal haemorrhage were analysed with HPLC and FC methods. The cut-off for HbF HPLC concentration was calculated. Statistical analyses for the evaluation of HPLC as a screening method were performed. The positivity cut-off of HbF to be used as decision-making value to continue the investigation was calculated. Results: An excellent agreement (R2 > 0.90) was observed between the percentage of HbF obtained by HPLC and the percentage of fetal cells detected by FC. Results obtained from each assay were compared to define the HPLC threshold below which it is not necessary to continue the investigations, confirming the maternal nature of the HbF positive cells detected. Our study demonstrated that a cut-off of 1.0 % HbF obtained by HPLC was associated with the lowest rate of false negative results in our patient cohort. Conclusions: This study provides a new FMH investigation approach that possibly leads to a reduction in times and costs of the analysis.

Presentation and progression of MPO-ANCA interstitial lung disease.

The association between MPO-ANCA-associated vasculitis (AAV) and interstitial lung disease (ILD) has been well established. Pulmonary fibrosis may coexist with, follow, or even precede the diagnosis of AAV, and its presence adversely affects the prognosis. The optimal approach to investigating ANCA in patients with ILD remains a subject of ongoing debate. Here we aim to describe presentation and progression of MPO-ANCA ILD. We conducted a retrospective evaluation of a cohort of individuals diagnosed with MPO-ANCA ILD, with or without accompanying renal impairment, at the Immunology and Cell Therapy Unit, Careggi University Hospital, Florence, Italy, between June 2016 and June 2022. Clinical records, imaging studies, pathologic examinations, and laboratory test results were collected. Among the 14 patients identified with MPO-ANCA ILD, we observed a significant association between MPO-ANCA titers assessed at the time of ILD diagnosis and renal involvement. Renal impairment in these cases often manifested as subclinical or slowly progressive kidney damage. Interestingly, complement C3 deposits were consistently found in all renal biopsy specimens, thereby suggesting the potential for novel therapeutic targets in managing renal complications associated with MPO-ANCA ILD. The presentation of MPO-ANCA vasculitis as ILD can be the first and only clinical manifestation. MPO-ANCA levels at ILD diagnosis could warn on the progression to renal involvement in patients with MPO-ANCA ILD, hence caution is needed because renal disease can be subclinical or smoldering.

Disseminated nocardiosis and anti-GM-CSF antibodies.

Infections that are unusually severe or caused by opportunistic pathogens are a hallmark of primary immunodeficiency (PID). Anti-cytokine autoantibodies (ACA) are an emerging cause of acquired immunodeficiency mimicking PID. Nocardia spp. are Gram-positive bacteria generally inducing disseminated infections in immunocompromised patients, but seldom also occurring in apparently immunocompetent hosts. Anti-GM-CSF autoantibodies are associated with autoimmune pulmonary alveolar proteinosis (PAP). In those patients, an increased incidence of disseminated nocardiosis and cryptococcosis has been observed. It is unclear whether the PAP or the autoantibodies predispose to the infection. We report an apparently immunocompetent woman presenting with disseminated nocardiosis without any evidence of PAP. Clinical data and radiological images were retrospectively collected. Lymphocyte populations were analyzed by flow cytometry. Anti-GM-CSF autoantibodies were measured by ELISA. A 55-year-old otherwise healthy woman presented with cerebral and pulmonary abscesses. Personal and familial history of infections or autoimmunity were negative. After extensive examinations, a final diagnosis of disseminated nocardiosis was made. Immunologic investigations including neutrophilic function and IFN-γ/IL-12 circuitry failed to identify a PID. Whole-exome sequencing did not find pathogenic variants associated with immunodeficiency. Serum anti-GM-CSF autoantibodies were positive. There were no clinical or instrumental signs of PAP. Trimethoprim-sulfamethoxazole and imipenem were administered, with progressive improvement and recovery of the infectious complication. We identified anti-GM-CSF autoantibodies as the cause of disseminated nocardiosis in a previously healthy and apparently immunocompetent adult. This case emphasizes the importance of including ACA in the differential diagnosis of PID, especially in previously healthy adults. Importantly, anti-GM-CSF autoantibodies can present with disseminated nocardiosis without PAP.

T lymphocytes-related cell network in the pathogenesis of juvenile idiopathic arthritis: a key point for personalized treatment.

PURPOSE OF REVIEW: Juvenile idiopathic arthritis (JIA) is a heterogeneous group of arthritis of unknown origin occurring in children under 16 years of age and persisting for at least 6 weeks. Given that JIA is an inflammatory disorder, treatment strategies, including also biologicals, are focused on suppressing excessive inflammation. The finding that different patients display different responses to biological drugs supports the concept that different pathogenic mechanisms can exist in JIA, with specific cellular and molecular mechanisms driving inflammation in each patient. The aim of this review is to highlight the most recent advances in understanding the role of immune cells in JIA pathogenesis. RECENT FINDINGS: This review encompasses the role of the different cell subsets involved in sustaining inflammation in JIA, with a particular emphasis on T cells, as they orchestrate both innate and adaptive auto-reactive immunity in affected joints. SUMMARY: The characterization of the cellular and molecular pathways supporting inflammation will be crucial to design novel therapeutic approaches in the context of personalized medicine.

Bendamustine impairs humoral but not cellular immunity to SARS-CoV-2 vaccination in rituximab-treated B-cell lymphoma-affected patients.

Background: Patients with B-cell lymphoma are a fragile category of subjects, particularly exposed to infections and characterized by an impaired vaccination response due to the disease itself and, even more, to the chemotherapy regimen. For this reason, extensive knowledge of the immune response status of these subjects is of fundamental importance to obtain possible indications for a tailored immunization strategy. Methods: We enrolled two cohorts of patients with B-cell lymphoma under rituximab treatment or 3-24 months after treatment. In all patients, we evaluated both humoral and cellular immunological memory toward SARS-CoV-2, after standard vaccination and upon one booster dose. Results: We observed no Spike-specific IgG production in patients (n = 25) under anti-CD20 treatment, whereas patients (n = 16) vaccinated after the completion of chemotherapy showed a higher humoral response. Evaluating SARS-CoV-2-specific T-cell response, we found that patients in both cohorts had developed robust cellular immunity after vaccination. Of the 21 patients (51%) that experienced a breakthrough SARS-CoV-2 infection, only six patients developed severe disease. Interestingly, these six patients had all been treated with rituximab plus bendamustine. Notably, we observed that Spike-specific IgG levels in patients treated with rituximab plus bendamustine were absent or lower compared with those in patients treated with rituximab plus other chemotherapy, whereas Spike-specific T-cell response was not different based on chemotherapy regiment. Discussion: Our results show that, in patients with B-cell lymphoma under rituximab therapy, anti-SARS-CoV-2 mRNA vaccination induces a weak or absent humoral response but a consistent T-cell response. In addition, chemotherapy regimens with bendamustine further reduce patients' ability to mount a Spike-specific humoral response even after a long time period from chemotherapy discontinuation. These results provide evidence that different chemotherapeutics display different immunosuppressive properties that could be taken in to account in the choice of the right drug regimen for the right patient. Moreover, they question whether immunocompromised patients, particularly those treated with bendamustine, need interventions to improve vaccine-induced immune response.