Donor-Derived Cell-Free DNA at 1 Month after Kidney Transplantation Relates to HLA Class II Eplet Mismatch Load.

Kidney transplantation is the preferred therapeutic option for end-stage renal disease; however, the alloimmune response is still the leading cause of renal allograft failure. To better identify immunologic disparities in order to evaluate HLA compatibility between the donor and the recipient, the concept of eplet load has arisen. Regular kidney function monitoring is essential for the accurate and timely diagnosis of allograft rejection and the appropriate treatment. Donor-derived cell-free DNA (dd-cfDNA) has been proposed as a potential biomarker of acute rejection and graft failure in kidney transplantation. The proportion of plasma dd-cfDNA was determined in forty-two kidney patients at 1 month after transplantation. A total of eleven (26.2%) patients had a dd-cfDNA proportion of ≥1.0%. The only pretransplant variable related to dd-cfDNA > 1.0% was the HLA class II eplet mismatch load, mainly the HLA-DQB1 eplet mismatch load. Furthermore, dd-cfDNA was able to discriminate the patients with antibody-mediated rejection (AbMR) (AUC 87.3%), acute rejection (AUC 78.2%), and troubled graft (AUC 81.4%). Increased dd-cfDNA levels were associated with kidney allograft deterioration, particularly rejection, as well as a greater HLA class II eplet mismatch load. Consequently, combining dd-cfDNA determination and HLA eplet mismatch load calculation should improve the assessment of the risk of short- and long-term allograft damage.

Clinical Features, Immunological Characteristics, and Treatment Outcomes of Campylobacter spp. Infections in Patients With Common Variable Immunodeficiency.

BACKGROUND: Campylobacter infection usually causes a self-limited clinical illness lasting 5 to 7 days, resolving without antimicrobial treatment in immunocompetent subjects. However, an inadequate immune response can lead to a prolonged and severe disease requiring antibiotics and more aggressive therapeutic approaches. OBJECTIVE: To comprehensively describe Campylobacter spp. infections in patients with common variable immunodeficiency (CVID). METHODS: A retrospective cohort of 14 CVID patients with Campylobacter infection and 95 CVID controls attending the immunology clinic at a large tertiary hospital was assessed. Immunological, clinical, and microbiological parameters were measured with median follow-up over 20 years in both cohorts. Patients were treated according to a novel algorithm for Campylobacter in antibody-deficient patients. RESULTS: Campylobacter patients had a higher proportion of CD21lowCD38low and transitional B cells (median 38.0% vs 14.2% and 5.4% vs 3.2%) and lower long-term average CD19+ B cells (median 0.06 vs 0.18 × 109/L) and CD4+ T cells (0.41 vs 0.62 × 109/L) in comparison with the controls. Similarly, Campylobacter patients showed a decline in B cells (median 0.02 vs 0.14 × 109/L), CD4+ T cells (0.33 vs 0.59 × 109/L), CD8+ T cells (0.26 vs 0.62 × 109/L), and natural killer cells (0.08 vs 0.18 × 109/L) over time. Antimicrobial resistance, especially to macrolides and fluoroquinolones, was common. Bacterial clearance with associated clinical improvement was obtained after a median of 20 and 113 days for acute Campylobacter (resolution within 3 mo of onset) and chronic Campylobacter (>3 mo) infections, respectively. Seven received first-line treatment (azithromycin or chloramphenicol), 4 second-line (neomycin), and 3 third-line (combination of tigecycline, chloramphenicol, and ertapenem; 1 received gentamicin owing to resistance to carbapenems). CONCLUSIONS: Our study highlights immunological and clinical characteristics of recurrent Campylobacter infections in patients with CVID. Our treatment algorithm was successful and should be evaluated in a larger cohort.

CD64 expression on neutrophils as a potential biomarker for bacterial infection in ascitic fluid of cirrhotic patients.

BACKGROUND: CD64 expression on neutrophils surface (CD64N) by flow cytometry has been validated as a rapid biomarker for bacterial infections in both peripheral blood and other biological fluids. Ascites is a common complication in cirrhotic patients that a variety of factors can cause, including bacterial infections. Manual counting of polymorphonuclear (PMN) cells in ascitic fluid and microbiologic culture are essential for its diagnosis. We aimed to validate the determination of CD64N by flow cytometry in ascitic fluid and assess its potential usefulness in the rapid identification of bacterial infections. MATERIALS AND METHODS: A prospective unicentre study was conducted. Flow cytometry was used to analyse the expression of CD64N in 77 ascitic fluid samples from the initial paracentesis of 60 cirrhotic patients in different admission episodes from November 2021 to December 2022. RESULTS: Seventeen samples were diagnosed with bacterial infection based on a positive microbiologic culture or by PMN count (>250 PMN/mm3 in ascitic fluid). The median of CD64N MFI was significantly increased in the bacterial infection group (3690.5 MFI [1635.23-6521.18] vs. 1105.9 MFI [737.3-2048.2], p < 0.001). The CD64 MFI ratio of granulocytes to lymphocytes was elevated in the bacterial infection group (13.06 [6.38-24.58] vs. 5.01 [3.38-7.36], p < 0.001). A CD64N ratio higher than 9.9 identified those patients with bacterial infection with 70.6 and 86.7% sensitivity and specificity, with an area under the curve (AUC) of 79.4%. CONCLUSION: The CD64N determined by flow cytometry on ascitic fluid could help quickly identify bacterial infections in ascites patients, allowing early antibiotic treatment.

Combined novel homozygous variants in both SGPL1 and STAT1 presenting with severe combined immune deficiency: case report and literature review.

Background: Sphingosine phosphate lyase insufficiency syndrome (SPLIS) is associated with biallelic variants in SGPL1, comprising a multisystemic disease characterized by steroid resistant nephrotic syndrome, primary adrenal insufficiency, neurological problems, skin abnormalities and immunodeficiency in described cases. Signal transducer and activator of transcription 1 (STAT1) plays an important role in orchestrating an appropriate immune response through JAK-STAT pathway. Biallelic STAT1 loss of function (LOF) variants lead to STAT1 deficiency with a severe phenotype of immunodeficiency with increased frequency of infections and poor outcome if untreated. Case presentation: We report novel homozygous SGPL1 and STAT1 variants in a newborn of Gambian ethnicity with clinical features of SPLIS and severe combined immunodeficiency. The patient presented early in life with nephrotic syndrome, severe respiratory infection requiring ventilation, ichthyosis, and hearing loss, with T-cell lymphopenia. The combination of these two conditions led to severe combined immunodeficiency with inability to clear respiratory tract infections of viral, fungal, and bacterial nature, as well as severe nephrotic syndrome. The child sadly died at 6 weeks of age despite targeted treatments. Conclusion: We report the finding of two novel, homozygous variants in SGPL1 and STAT1 in a patient with a severe clinical phenotype and fatal outcome early in life. This case highlights the importance of completing the primary immunodeficiency genetic panel in full to avoid missing a second diagnosis in other patients presenting with similar severe clinical phenotype early in life. For SPLIS no curative treatment is available and more research is needed to investigate different treatment modalities. Hematopoietic stem cell transplantation (HSCT) shows promising results in patients with autosomal recessive STAT1 deficiency. For this patient's family, identification of the dual diagnosis has important implications for future family planning. In addition, future siblings with the familial STAT1 variant can be offered curative treatment with HSCT.

DQA1 Eplet Mismatch Load As an Independent Risk Factor of CLAD After Lung Transplantation.

Lung transplantation remains the treatment of choice for end-stage lung diseases, and recipient selection is currently based on clinical urgency, ABO compatibility, and donor size. The risk of allosensitization is classically based on HLA mismatch, but eplet mismatch load is increasingly seen to be important in long-term outcomes in solid organ transplantation. Chronic lung allograft dysfunction (CLAD) is relatively common and relevant, affecting almost 50% of patients 5 y after transplantation and being the first cause of death from the first year after transplantation. The overall class-II eplet mismatch load has been associated with CLAD development. Methods: Based on clinical data, 240 lung transplant recipients were eligible for CLAD, and HLA and eplet mismatch was analyzed using the HLAMatchmaker 3.1 software. Results: A total of 92 (38.3%) lung transplant recipients developed CLAD. The time free-of-CLAD was significantly decreased in patients with presence of DQA1 eplet mismatches (P = 0.015). Furthermore, when other previously described CLAD risk factors were studied in a multivariate analysis, the presence of DQA1 eplet mismatches was found to be independently associated with the early onset of CLAD. Conclusions: The concept of epitope load has arisen as a new tool to better define donor-recipient immunologic compatibility. The presence of DQA1 eplet mismatches potentially would increase the likelihood of developing CLAD.

Estimation of Antibody-Verified Eplet Mismatch Load, 2-Field HLA Resolution vs Imputation in a Large Cohort of European Donors.

BACKGROUND: The assessment of class II eplet mismatch load is useful to determine the risk of chronic rejection in solid organ transplantation. However, high-resolution (2-field) HLA typing is mandatory to accurately define eplet mismatches. The imputation of the most frequent allele has been used in retrospective studies. Here, we sought to investigate the concordant of antibody-verified (AbV) eplet load in different class II alelles between real 2-field HLA typing and HLA imputed by most frequent allele in a large White cohort. MATERIALS AND METHODS: The allelic frequency of the different HLA class II loci was calculated using a database of high-resolution typing of 23,628 voluntary Spanish bone marrow donors obtained from the Spanish Registry of Bone Marrow Donors, managed by the Josep Carreras Foundation. The AbV eplet count in the different class II alleles was performed using the HLA-Matchmaker v3.1 algorithm. RESULTS: The probability of imputing the correct allele compared to the most frequent for DRB1 and DQB1 loci was 69.3% and 53.0%, respectively. However, studying the less frequent alleles, the same AbV eplet load was observed in 82.22% and 76.15%, respectively. CONCLUSIONS: Our data show that despite the potential error in the imputation of class II HLA typing, the number of AbV eplets is not significantly over- or underestimated in our population. Until high-resolution typing is widely established for solid organ transplantation, retrospective studies of AbV eplet mismatch load with imputed high-resolution types provide an acceptable outcome in White people.

Non-HLA Antibodies and Their Role in Highly Sensitized Patients.

BACKGROUND: The role of non-HLA antibody is gaining special attention in solid-organ transplantation and in highly sensitized (HS) patients because of its potential involvement in graft loss (GL) and/or antibody-mediated rejection (ABMR). The identification of non-HLA antibodies while listed may provide deeper information about the increased immunologic risk prior to transplant. We aimed to identify non-HLA antibodies pretransplant that could involve GL in HS patients. METHODS: Nineteen pretransplant samples from HS patients who underwent transplant at the Marqués de Valdecilla University Hospital were studied for both HLA antibodies and a panel of 39 non-HLA antigens analyzed based on Luminex platform. RESULTS: Eleven patient (57.9%) maintained the graft (KT group), whereas 8 (42.1%) had a GL within a median of 30 days. The median fluorescent intensity (MFI) of the 39 non-HLA antigens were compared within the groups, obtaining a statistically significant differences in protein tyrosine phosphatase receptor type N (P < .04) with a MFI mean of 1408 vs 4931 for KT and GL groups, respectively. However, no significant differences were observed in non-HLA MFI between ABMR and non-ABMR KT recipients. CONCLUSIONS: The presence of non-HLA antibodies in HS is high. The levels of anti-protein tyrosine phosphatase receptor type N before transplant could indicate a potential risk of GL, although longitudinal studies with large number of cases are needed to define anti-non-HLA profiles of risk of ABMR.

Analysis of Serum Proteome after Treatment of Osteoporosis with Anabolic or Antiresorptive Drugs.

The aim of the study was to explore new markers in serum proteome associated with the response to antiosteoporosis drugs, namely teriparatide and denosumab. We obtained serum samples from 14 patients with osteoporosis, both at baseline and after 6 months of treatment with teriparatide (n = 10) or denosumab (n = 4). Samples were analyzed by nanoliquid chromatography coupled to high-resolution mass spectrometry on a QTOF 5600 (SCIEX) apparatus. The spectrometry data were analyzed with Mascot against the UniProtKB base and then several quality-control filters were applied for the identification of peptides (false discovery rate, FDR q < 0.02) and their quantification (FDR q < 0.05). In the group treated with teriparatide, 28 proteins were identified with significant differences before and after treatment. A pathway analysis by using the Reactome database revealed significant enrichment in the Insulin Like Growth Factor 1 (IGF-I) (FDR q 4 × 10−2) and innate immune system (FDR q 2 × 10−3) pathways. Among patients treated with denosumab, we observed significant differences in the levels of 10 proteins, which were also enriched in the pathways related to the innate immune system (FDR q 3 × 10−2). These results suggest that the innate immune system may be involved in the response to antiosteoporosis drugs.

Deletion in the BCL11B Gene and Intellectual Developmental Disorder with Speech Delay, Dysmorphic Facies, and T-cell Abnormalities - a Case Report.

Herein we described a retrospective analysis of a 13-year-old female patient with facial dysmorphia and immune disorder caused by BCL11B gene mutation. The patient upon physical examination presented a particular face (thin eyebrows, small mandible, and widened eye distance), delayed language and motor development. Supplementary examination showed expansion of CD8+, absence of type 2 Innate Lymphoid Cells, increased IgG and altered distribution of T cells. Genetic testing revealed a heterozygous frameshift variation in exon 4 of the BCL11B gene; c.1887_c.1893delCGGCGGG (p.Gly630Glyfs*91). Finally, a BCL11B gene mutation could lead to abnormal development of the nervous and immune systems, therefore, it is necessary to consider this syndrome in patients with the clinical and immunological phenotype described below.

Immune Checkpoint Inhibitors: The Emerging Cornerstone in Cholangiocarcinoma Therapy?

BACKGROUND: Cholangiocarcinoma (CCA) encompasses a heterogeneous group of malignant tumors with dismal prognosis and increasing incidence worldwide. Both late diagnosis due to the lack of early symptoms and the refractory nature of these tumors seriously compromise patients' welfare and outcomes. SUMMARY: During the last decade, immunotherapy and, more specifically, modulation of immune checkpoints-mediated signaling pathways have been under the spotlight in the field of oncology, emerging as a potential therapeutic approach for the treatment of several cancers, including CCA. Generally, high expression levels of immune checkpoints in patients with CCA have been associated with worse clinical outcomes, particularly with shorter overall survival and relapse-free survival. Thus, immune checkpoint inhibitors (ICIs), which mainly constitute different monoclonal antibodies, have been developed in order to hamper the immune checkpoint-mediated pathways. Interestingly, chemotherapy may increase the expression of immune checkpoints, while other therapeutic approaches such as ablative and targeted therapies may enhance their antitumor activity. In this sense, several clinical trials evaluated the safety and efficacy of ICIs for CCA, both as a monotherapy and in combination with other ICIs or loco-regional and systemic therapies. Additionally, many other clinical trials are currently ongoing and results are eagerly awaited. Here, we summarize the key aspects of immune checkpoint molecules as prognostic factors and therapeutic targets in CCA, highlighting the most recent advances in the field and future research directions. KEY MESSAGES: (1) Effective therapeutic approaches for CCA are urgently needed. (2) Expression levels of immune checkpoints in patients with CCA have been proposed to be related with clinical outcomes. (3) Combination of different ICIs may outperform the efficacy of ICI monotherapy for CCA treatment. (4) Recent studies point toward the combination of ICIs and other common therapies, especially chemotherapy, as a promising strategy for treatment of CCA patients.

Immune Assessment of BNT162b2 m-RNA-Spike Based Vaccine Response in Adults.

Vaccine efficacy is based on clinical data. Currently, the assessment of immune response after SARS-CoV-2 vaccination is scarce. A total of 52 healthcare workers were immunized with the same lot of BNT162b2 vaccine. The immunological response against the vaccine was tested using a T-specific assay based on the expression of CD25 and CD134 after stimulation with anti-N, -S, and -M specific peptides of SARS-CoV-2. Moreover, IgG anti-S2 and -RBD antibodies were detected using ELISA. Furthermore, the cell subsets involved in the response to the vaccine were measured in peripheral blood by flow cytometry. Humoral-specific responses against the vaccine were detected in 94% and 100% after the first and second doses, respectively. Therefore, anti-S T-specific responses were observed in 57% and 90% of the subjects after the first and second doses of the vaccine, respectively. Thirty days after the second dose, significant increases in T helper 1 memory cells (p < 0.001), peripheral memory T follicular helper (pTFH) cells (p < 0.032), and switched memory (p = 0.005) were observed. This study describes the specific humoral and cellular immune responses after vaccination with the new mRNA-based BNT162b2 vaccine. A mobilization of TFH into the circulation occurs, reflecting a specific activation of the immune system.

Validation of a Quick Flow Cytometry-Based Assay for Acute Infection Based on CD64 and CD169 Expression. New Tools for Early Diagnosis in COVID-19 Pandemic.

Objectives: Several parameters aid in deciphering between viral and bacterial infections; however, new tools should be investigated in order to reduce the time to results and proceed with an early target-therapy. Validation of a biomarker study, including CD64 and CD169 expression, was conducted. Material and Methods: Patients with active SARS-CoV-2 infection (ACov-2), bacterial infection (ABI), healthy controls, and antiretroviral-controlled chronic HIV infection were assessed. Whole blood was stained and, after lysing no-wash protocol, acquired by flow cytometry. The median fluorescence intensity (MFI) of CD64 and CD169 was measured in granulocytes, monocytes, and lymphocytes. The CD64 MFI ratio granulocytes to lymphocytes (CD64N) and CD169 MFI ratio monocytes to lymphocytes (CD169Mo) were evaluated as biomarkers of acute bacterial and viral infection, respectively. Results: A CD64N ratio higher than 3.3 identified patients with ABI with 83.3 and 85.9% sensitivity and specificity, with an area under the curve (AUC) of 83.5%. In contrast, other analytic or hematological parameters used in the clinic had lower AUC compared with the CD64N ratio. Moreover, a CD169Mo ratio higher than 3.3 was able to identify ACov-2 with 91.7 and 89.8 sensitivity and specificity, with the highest AUC (92.0%). Conclusion: This work confirms the previous data of CD64N and CD169Mo ratios in an independent cohort, including controlled chronic viral HIV infection patients as biomarkers of acute bacterial and viral infections, respectively. Such an approach would benefit from quick pathogen identification for a direct-therapy with a clear application in different Health Care Units, especially during this COVID pandemic.