Analysis of Risk Factors for a Low Immune Response to Messenger RNA COVID-19 Vaccine in Kidney Transplant Recipients and Differences Between Second and Third Dose.

BACKGROUND: The efficacy of the response to SARS-CoV-2 vaccination in kidney transplant recipients is low. The aim of our study was to evaluate the risk factors correlated with the low antibody response and whether there was an improvement between the second and the third dose. METHODS: A prospective study was conducted on 176 kidney transplant recipients who received the second and the third dose of the anti-SARS-CoV-2 mRNA Comirnaty vaccine. We evaluated the seroconversion process after administration of the second and the third dose and assessed a possible correlation with age, time between transplant and vaccination, and type of immunosuppressive therapy. RESULTS: A total of 98 of the 176 patients (55.7%) responded positively after the inoculation of the second dose and according to the multivariable logistic regression analysis the lack of seroconversion was independently associated with patient age ≥60 (P = .025; odds ratio [OR], 2.094), time since transplant of 1 to 3 months (P = .032; OR, 2.118), and triple therapy (P = .044; OR, 2.327). After the vaccine third dose, the seroconversion increased to 62.5%, and it was negatively influenced by calcineurin inhibitor use (12/21, 57.1% vs 71/78, 91.0%, P = .0006) and triple therapy (13/21, 61.9% vs 72/78, 92.3%, P = .0014). The median of antispike antibody response significantly increased from 18.5 IU/mL after the second dose to 316.9 IU after the third dose (P < .0001). CONCLUSIONS: We demonstrated a correlation between older age and shorter distance from the transplant and triple immunosuppressive therapy with the lack of seroconversion. We noticed a significant improvement in antibody response by a third dose of messenger RNA vaccine.

Influence of cytotoxic T-lymphocyte antigen-4 polymorphisms on acute rejection onset of cadaveric renal transplants.

We retrospectively examined in cadaveric renal transplants the association between acute rejection episodes (ARE) and single nucleotide polymorphisms (SNPs) localized in the cytotoxic T-lymphocyte antigen (CTLA)-4 promoter, -1147T/C and -318C/T, in exon 1 +49A/G and within the 3' untranslated region (UTR) CT60G/A. Each one of these SNPs may influence the cell surface expression of the CTLA-4 molecule. Seventy-two cadaveric renal transplant recipients with at least 6 month's follow-up were genotyped for CTLA-4 dimorphisms using direct sequencing of specific polymerase chain reaction products. Allele frequencies in both groups of patients with or without acute rejection (ARE and non-ARE) did not show significant differences in various nucleotide positions. At the level of genotype frequency we first noted a positive association to acute rejection of G/G genotypes (ARE af = 14.7%, non-ARE af = 5.9%) for the +49 (cod. 17), which was associated with decreased expression of the CTLA-4 full-length molecule. In contrast, the AG genotype seemed to be protective (61.8% vs 32.4%, P = .028; odds ratio [OR] = 0.2961). Regarding the CT60G/A dimorphism, noteworthy was the identification of a significantly higher incidence of CT60 A/A genotype in ARE compared with non-ARE group (29.7% vs 8.6%; Yates P = .035; OR = 4.51). Such association of protective AA genotype with ARE, as observed also in autoimmunity, was associated with an increased level of sCTLA-4 induced by the polymorphism, which blocks B7-flCTLA-4 interactions, enhancing T-cell reactivity by preventing transduction of inhibitory signals. Considering the various polymorphic sites in the haplotype, we observed a significant increase in ARE among patients of the CTLA4 +49A/CT60A (HF = 51.5% vs 29.5%; P = .014; OR = 2.545) and a reduction among the +49A/CT60G (17.6% vs 33.8%; P = .04; OR = 0.4193) 2-loci haplotype, As regards the -1147/-318/+49/CT60 CTLA-4 4-loci haplotypes, we observed a significantly higher frequency of the CCAA haplotype in ARE patients comparison with those free of rejection (HF = 51.8% vs 31.1%, P = .046 OR = 2.363). These findings are consistent with those observed in allogeneic stem cell transplantation, wherein patients with CT60 AA showed a major incidence of graft-versus-host disease. An association of protective AA genotype with ARE, as observed also in autoimmunity was associated with an increased level of sCTLA-4 induced by this polymorphism, which blocking the B7-flCTLA-4 interaction, would enhance T-cell reactivity by preventing transduction of inhibitory signals.

For anti-HLA-specific donor antibodies detection by flow cytometry cytotoxic crossmatches comparison of methods.

Anti-HLA-specific donor antibodies induce rapid, irreversible destruction of the transplant (hyperacute rejection) that today happens rarely due to immunologic studies-prospective crossmatch-of patients awaiting the kidney graft. The usual approach for pretransplant donor/recipient evaluation is based on 2 methods: (1) the cytotoxic complement crossmatch (CDC) and (2) the flow cytometric crossmatch (FCX). The CDC crossmatch is positive when complement-fixing antibodies are present, an absolute contraindication to kidney transplantation. The more sensitive FCX-positive crossmatch detects low concentrations of unable to fix performed antibodies complement. It is an "index" of possible damage due to accelerated rejection. The target of our study was to develop a cytotoxic flow cytometry crossmatch (cFCX) that detected cytotoxic antibodies move sensitively than the traditional CDC method and also was less subjective and more standardized for interpretation studying sera from 23 patients; the cFCX showed the requested efficiency characteristics even in an emergency. In addition, the new method permited one to calculate a cutoff for positivity (average value of the negative control + 2 standard deviations), assuring an "objective" interpretation of the results that agreed with the CDC but was more sensitive and accurate allowing solution of ambiguous results for cases of "doubt"-positive CDC crossmatch. Furthermore, our aim was to correlate the effect of the strength of the anti-HLA antibodies determined by mean fluorescence intensity value of LabScreen Single Antigen beads with results of CDC, cFCX, and FCX methods.

Identification of the novel HLA-B*50:18 allele variant in an Italian unrelated bone marrow donor.

The HLA-B*50:18 allele differs from the closest related B*50:01:01 by one nucleotide substitution at position 454 in exon 3.

Sequence-based typing identification of the novel HLA-A*24:135 variant in a Maldivian family with a bone marrow patient.

We describe the identification of the novel HLA-A*24:135 allele [nucleotide 397 (T→C) in exon 3, Phe→Leu at codon 109 in α2 domain, compared with A*24:02:01] by sequence-based typing (SBT).

Evaluation of serum sCD30 in renal transplantation patients with and without acute rejection.

Despite new immunosuppressive approaches, acute rejection episodes (ARE) are still a major cause of early kidney dysfunction with a negative impact on long-term allograft survival. Noninvasive markers able to identify renal ARE earlier than creatinine measurement include sCD30. We sought to establish whether circulating levels of sCD30 in pretransplantation and posttransplantation periods were of clinical relevance to avoid graft damage. Quantitative detection of serum sCD30 was performed using an enzyme-linked immunosorbent assay. Our results demonstrated that the mean concentrations of sCD30 were significantly higher in the sera of renal transplant recipients with ARE (30.04 U/mL) and in uremic patients on the waiting list (37.7 U/mL) compared with healthy controls (HC; 9.44 U/mL), but not nonrejecting patients (12.01 U/mL). Statistical analysis revealed a strong association between high sCD30 levels in posttransplantation sera and ARE risk. This study suggested that sCD30 levels were a reliable predictor of ARE among deceased-donor kidney recipients.

Interferon-alpha therapy and anti-human leukocyte antigen antibodies in hepatitis C virus-positive patient: case report.

Interferon-alpha (IFN-alpha) is currently the only treatment for patients with chronic hepatitis C. Yet it can induce acute renal transplantation rejection possibly by stimulating humoral responses. We tested patient sera for detection of donor-specific anti-human leukocyte antigen (HLA) antibodies observing an increased panel-reactive antibodies value after IFN-alpha therapy. Then, we also investigated whether antiviral treatment with IFN-alpha was related to an increased and/or different production of class I and class II anti-HLA antibodies. Patient sera analysis performed by a cytofluorimetric method using flow PRA tests showed the appearance of new HLA-antibody specificities. This study underlined that INF-alpha therapy modifies a patient's immune profile; hence, it is recommended to confirm HLA-antibody specificities after treatment in order to protect recipients from enhanced rejection risk owing to a false-negative donor-specific cross-match.

Genetic predisposition to rheumatoid arthritis in a Tuscan (Italy) ancient human remain.

Rheumatoid arthritis (RA) is currently believed to have originated in America, and after the discovery of this continent in 1492, to have been exported to the Old World. We evaluated the genetic predisposition to RA in the "Braids Lady" from Arezzo (Italy), a partially mummified woman's body dating back to the end of 1500 AD which presents the anatomical and pathological features of this disease. The study of the polymorphic HLA-DRB1 locus, which includes alleles strongly associated with RA onset, has received much attention over recent years, especially the loci codifying for the DR1 and DR4 antigens, widely represented in the Mediterranean population, and for DR14, widespread among Native Americans. Molecular analysis was performed on extracts of DNA from the mummy, firstly from histological bone sections and then from the whole bone. Two different HLA typing techniques, PCR-sequence-specific oligonucleotides (PCR-SSO) and PCR-sequence-specific primers (PCR-SSP), were employed to identify HLA-DRB alleles. Both genotyping methods showed that the "Braids Lady" carried the DRB1*0101 allele, the serological equivalent of the DR1 antigen. Although the possession of RA risk factor genes cannot be considered a diagnostic marker, the positive result of the Italian mummy for DRB1*0101 and the RA features present, support the idea that this pathology was present in the Old World from at least the mid-16th century. A pathogenetic hypothesis of RA which might well explain its worldwide diffusion is the "molecular mimicry", resulting from a cross-reactive antibody response between certain microbial antigens and shared epitopes of specific HLA-DR1, DR4 and DR14 susceptibility alleles, the frequency of which varies among different ethnic groups.

Waiting list for kidney transplants.

Medical and technological progress have made kidney transplants an effective, alternative therapy to dialysis for patients suffering from chronic kidney failure. Transplantation improves the quality of life of these patients significantly; however, waiting lists are long and this is because of the attitude of the general public to organ donation, not a lack of medical expertise. In fact, the only limiting factor in kidney transplant is the opposition to donation expressed by the deceased or family members. Herein we outline the distribution of patients on the kidney transplant waiting list in the Regional Transplant Centre for Abruzzo and Molise in L'Aquila, Italy, and highlight the reasons why patients are withdrawn from the list, the main reason being a deterioration in patient condition after long periods of dialysis.

Anti-HLA antibodies in kidney transplanted patients.

Anti-human leukocyte antibodies (HLA) play a central role in graft survival, particularly in kidney transplantation. The presence of preformed donor specific anti-HLA antibodies is always excluded before transplantation by performing crossmatches using current and historic recipient serum samples. Several recent studies have observed a correlation between HLA antibodies and graft rejection. It has been suggested that these antibodies should be monitored routinely after kidney transplant to predict graft failure. Here in report the results of a study of on serum samples from 111 kidney transplant recipients that were monitored for anti-HLA antibodies using flow cytometry. Anti-HLA antibodies were only detected in four pre-immunized patients and showed the same HLA specificity that was present before the transplantation (in two cases against previous graft antigens). Furthermore, only two patients with functioning grafts developed anti-HLA antibodies, at 1 month and 1 year after the transplantation. However, they were not donor specific, but probably related to posttransplant transfusions. In our study, none of the patients who suffered an adverse event during the first year (including two with histologically documented acute rejection) developed anti-HLA antibodies. These results are probably related to the use of mycophenolate mofetil, which may reduce the incidence of HLA antibodies. We cannot exclude the possibility that antibodies produced by some patients may not be detectable because they are attached to the graft.

Identification of the novel allele B*4427 and a confirmatory sequence (B*44022).

This report presents a novel allele, HLA-B*4427, which was identified in a bone marrow donor of Caucasian origin, and a confirmatory sequence (B*44022). Sequence analysis revealed the new allele differs from B*44021 by a single nucleotide exchange at position 668 (C-->T), which is located in exon 4. At the protein level, it is the only B*44 variant to produce an Ala in place of a Val at codon 199. Its structure suggests that it may have originated from a point mutation in B*44021 or by gene conversion with a variety of HLA-B alleles. Cloning and sequencing of the allele B*44022 revealed a sequence identical to B*44021 and B*44 exon 4, with the codon GTC (Val) in position 199.

Immunosuppressive molecules produced by Sertoli cells cultured in vitro: biological effects on lymphocytes.

In the present study we have analyzed the proteins secreted in vitro by murine Sertoli cells to identify immunosuppressive factors. Our data show that Sertoli cells secrete molecules capable to inhibit proliferation of lymphocytes activated in vitro. Cytophluorimetric analysis indicates that treated cells are arrested in the G1 phase of cell cycle. The inhibitory activity is specific for both B or T lymphocytes but not for other non-lymphoid cells and is associated to proteins, heat and freeze stable, with Mr of more than 30 kDa. Lymphocytes treated with Sertoli immunosuppressive proteins drastically reduce the secretion of interleukin-2.