Association Between HLA Antibodies and Different Sensitization Events in Renal Transplant Candidates

Ageing on the impact of distribution about preformed anti-HLA and anti-MICA antibody specificities in recipients prior to initial HSCT from East China

BACKGROUND

With the development of Hematopoietic Stem Cell Transplantation (HSCT) technology, increasing numbers of elderly patients were undergoing allogeneic HSCT and elderly patients with hematologic malignancies could benefit most from it. Preformed donor-specific human leukocyte antigen (HLA) antibodies (DSA) were associated with graft failure in HLA-mismatched allogeneic HSCT and the absence of DSA was the main criterion of selecting the donor. Except for sensitization events such as transfusion, pregnancy or previous transplantation, ageing affects the humoral immune response both quantitatively and qualitatively. To evaluate the prevalence and distribution of anti-HLA and antibodies of MHC class I chain related antigens A (MICA) specificities in different age groups before initial HSCT would provide HLA and MICA specific antibody profiles under the impact of ageing, which could provide meaningful information in the process of selecting suitable HLA-mismatched donors by avoiding preformed DSA.

RESULTS

There were no significant differences in the distribution of anti-HLA class I, class II and anti-MICA antibodies among the three age groups in this study except that a significant lower negative ratio of anti-HLA class I, class II antibodies and higher positive rate of MICA antibodies with maximum mean fluorescent intensity (MFI) > 5000 in the elderly than in young age group. The distribution of antibody specificities against HLA -A, -B, -C, -DR, -DQ, -DP and MICA antigens in the three age groups were generally consistent. The anti-HLA class I antibody specificities with higher frequencies were A80,A68;B76,B45;Cw17, which were unlikely to become DSA in Chinese. Anti-HLA class II antibody specificities were more likely to become potential DSA than class I.DR7, DR9, DQ7, DQ8 and DQ9 were most likely to become potential DSA.

CONCLUSIONS

The prevalence of anti-HLA and anti-MICA antibodies increased slightly as age increased. While ageing had a small impact on the distribution of antibody specificity frequencies against HLA-A, -B, -C, -DR,-DQ, -DP and MICA antigens in recipients awaiting initial HSCT from East China. The risk of developing preformed DSA was basically consistent in the three age groups and the elderly group might be more favorable in HLA-mismatched HSCT due to higher positive rate of anti-MICA antibody.

The correlation of results of panel reactive antibody, identification, and single antigen beads in detection of anti-HLA antibodies: Istanbul Faculty of Medicine, tissue typing laboratory experience

BACKGROUND

We have performed a retrospective analysis of anti-HLA class I MHC and class II MHC antibodies measured using a single antigen bead (SAB) assay and a panel reactive antibody (PRA) assay.

MATERIAL AND METHODS

A group of 256 patients with end-stage renal disease (ESRD) was tested for anti-HLA antibodies in the tissue typing laboratory between 2017 and 2020. In the cohort, the serum samples of patients waiting for transplantation were tested. Both the PRA and SAB tests of these patients were analyzed using the Luminex (Immucor) method. The threshold of positivity was accepted as median fluorescence intensities (MFI) ≥1000 for PRA screening and MFI ≥750 for SAB screening.

RESULTS

Overall, antibodies to HLA antigens were detected in 202 (78.9%) out of 256 patients in the PRA study. Antibodies against both class I/II antigens were detected only in 15.6% of these patients, whereas antibodies against only against class I HLA in 31.3% and only against class II HLA in 32.0%. By comparison, the SAB study found that 66.8% of patients were positive for HLA antigens. Furthermore, donor-specific antibodies (DSA) were detected in 52.0% of PRA-positive patients and 52.6% of SAB-positive patients. It was shown that 168 patients (83.2%) out of 202 PRA-positive patients were found to be SAB-positive. In addition, 51 patients negative in the SAB assay (94.4%) were also negative in the PRA assay. Statistical analysis established a significant correlation between the PRA and SAB positivity (p > 0.001). It was also shown that MFI ≥3000 PRA positivity for class I HLA antigens (p = 0.049) and MFI ≥5000 PRA positivity for class II antigens (p < 0.001) correlated with the SAB positivity in patients.

CONCLUSION

Our results showed the importance of both PRA and SAB assays to define the status of sensitization in patients.

COVID-19 infection and vaccination rarely impact HLA antibody profile in waitlisted renal transplant Candidates- a multicenter cohort

Although rare, infection and vaccination can result in antibodies to human leukocyte antigens (HLA). We analyzed the effect of SARS-CoV-2 infection or vaccination on HLA antibodies in waitlisted renal transplant candidates. Specificities were collected and adjudicated if the calculated panel reactive antibodies (cPRA) changed after exposure. Of 409 patients, 285 (69.7 %) had an initial cPRA of 0 %, and 56 (13.7 %) had an initial cPRA > 80 %. The cPRA changed in 26 patients (6.4 %), 16 (3.9 %) increased, and 10 (2.4 %) decreased. Based on cPRA adjudication, cPRA differences generally resulted from a small number of specificities with subtle fluctuations around the borderline of the participating centers' cutoff for unacceptable antigen listing. All five COVID recovered patients with an increased cPRA were female (p = 0.02). In summary, exposure to this virus or vaccine does not increase HLA antibody specificities and their MFI in approximately 99 % of cases and 97 % of sensitized patients. These results have implications for virtual crossmatching at the time of organ offer after SARS-CoV-2 infection or vaccination, and these events of unclear clinical significance should not influence vaccination programs.

Effect of panel reactive antibodies on T cell immunity reinstatement following renal transplantation

BACKGROUND

Chronic kidney disease is associated with immunological disorders, presented as phenotypic alterations of T lymphocytes. These changes are expected to be restored after a successful renal transplantation; however, additional parameters may contribute to this process.

AIM

To evaluate the impact of positive panel reactive antibodies (PRAs) on the restoration of T cell phenotype, after renal transplantation.

METHODS

CD4CD28null, CD8CD28null, natural killer cells (NKs), and regulatory T cells (Tregs) were estimated by flow cytometry at T0, T3, and T6 which were the time of transplantation, and 3- and 6-mo follow-up, respectively. Changes were estimated regarding the presence or absence of PRAs.

RESULTS

Patients were classified in two groups: PRA(-) (n = 43) and PRA(+) (n = 28) groups. Lymphocyte and their subtypes were similar between the two groups at T0, whereas their percentage was increased at T3 in PRA(-) compared to PRA(+) [23 (10.9-47.9) vs 16.4 (7.5-36.8 μ/L, respectively; P = 0.03]. Lymphocyte changes in PRA(-) patients included a significant increase in CD4 cells (P < 0.0001), CD8 cells (P < 0.0001), and Tregs (P < 0.0001), and a reduction of NKs (P < 0.0001). PRA(+) patients showed an increase in CD4 (P = 0.008) and CD8 (P = 0.0001), and a reduction in NKs (P = 0.07). CD4CD28null and CD8CD28null cells, although initially reduced in both groups, were stabilized thereafter.

CONCLUSION

Our study described important differences in the immune response between PRA(+) and PRA(-) patients with changes in lymphocytes and lymphocyte subpopulations. PRA(+) patients seemed to have a worse immune profile after 6 mo follow-up, regardless of renal function.

Effects of different sensitization events on HLA alloimmunization in renal transplant cases; a retrospective observation in 1066 cases

BACKGROUND

Patients awaiting solid organ transplantation may develop anti-HLA antibodies after sensitization events such as transfusions, pregnancies, or previous transplantations. However, the effects of a particular sensitization event on HLA alloimmunization have not been well studied in parallel using cell-based assays and solid-phase assays. In this study, we evaluated and compare how different sensitization events affect the HLA antibody screening (HLA-Ab) and donor specific antibody (DSA) status in solid renal organ transplantation patients.

METHODS

HLA antibody (HLA-Ab) screening tests like complement-dependent cytotoxicity crossmatch (CDC-XM), flow cytometry crossmatch (FC-XM) & Luminex panel-reactive antibody (L-PRA) were performed in all 1066 patients (635 males and 431 females). If any of these tests turned out to be positive, a Luminex single antigen bead (L-SAB) assay was performed for DSA identification. Test positive rates and antibody strengths were analyzed according to the different sensitization events and gender.

RESULTS

In this study, HLA-Ab screening tests positive rates (L-PRA, FC-XM and CDC-XM) were significantly higher in patients with previous transplantation (73.91%, 86.95% and 56.52% p < 0.001), previous pregnancy (57.46%, 70.14% and 18.85% p < 0.001) or blood transfusion (27.33%, 35.55% and 7.33% p < 0.001) compared with patients without a sensitizing event (6.17%, 13.58% & 1.09). In this study, re-transplantation group showed significantly stronger antibody strength (DSA) than non sensitized group (class I & II MFI 11418.04, 17,837.78 vs class I & II MFI 2659, 3329; P < 0.001) and those with single sensitization events of transfusion (class I & II MFI 11418.04, 17,837.78 vs class I & II MFI 5598.82, 5436.12; P < 0.001) or pregnancy (class I & II MFI 11418, 17,837 vs class I & II MFI 8580.12, 7556.08; P < 0.001).

CONCLUSIONS

Pregnancy and blood transfused had high allo-immunization rate for class I HLA antigens. While re-transplantation patients had high allo-immunization rate for both the HLA classes (HLA- class I & HLA- class II). Re-transplantation group showed significantly stronger antibody strength, followed by pregnancy and then transfusion.

Prevalence and risk factors of antibodies to HLA according to different cut-off values of mean fluorescence intensity in haploidentical allograft candidates: A prospective study of 3805 subjects

The importance of anti-HLA antibodies in transplantation settings, such as HLA-mismatched or haploidentical hematopoietic stem cell transplantation and platelet refractoriness, is widely recognized. In previous reports, it was mentioned that several cut-off values of donor-specific anti-HLA antibodies mean fluorescence intensity (MFI) were related to graft rejection in the environment of HLA mismatched stem cell transplantation and the aim of this study was to investigate the prevalence and risk factors of anti-HLA antibodies according to those cut-off values of MFI. A total of 3805 patients with hematologic disease were prospectively enrolled and analyzed. When using MFI of anti-HLA antibodies ≥500, ≥1000, ≥1500, ≥2000, ≥5000, and ≥ 10,000 as cut-off values for positivity, the prevalence of class I or II anti-HLA antibodies ranged from 4.6% to 20.2% in all cases. When the MFI cut-off value was ≥500 for positivity, multivariate analysis indicated that platelet transfusion, underlying disease, and pregnancy were the most important risk factors for the presence of anti-HLA antibodies for the total patients. Subgroup analysis according to age, gender, and underlying disease showed that pregnancy was the most important risk factor for the presence of anti-HLA antibodies. For all patients (n = 3805), when anti-HLA antibody positivity was defined according to different MFI cut-off values, including ≥1000, ≥1500, ≥2000, ≥5000, and ≥ 10,000, an association of platelet transfusion and pregnancy with anti-HLA antibodies was also demonstrated. Our results suggest that pregnancy and platelet transfusion are the main risk factors for the prevalence of anti-HLA antibodies in haploid allograft candidates, providing evidence for guiding the evaluation of anti-HLA antibodies and helping donor selection for HLA-mismatched transplant candidates.

The Impact of Panel Reactive Antibodies and Different Desensitization Methods on Pediatric Allogeneic Hematopoietic Stem Cell Transplantation Outcomes

INTRODUCTION

In highly sensitized patients who have panel reactive antibodies (PRAs) before hematopoietic stem cell transplantation, primary graft failure risk may increase. In this study, we aimed to determine the association of PRA with engraftment, and graft versus host disease (GVHD) in pediatric patients.

MATERIALS AND METHODS

Forty-three PRA-positive and 42 PRA-negative patients were taken into study. Both groups were compared in terms of graft failure, acute GVHD, viral infection and survival rates. PRA-positive group was also divided into 2 according to treatment modality (steroid-only group/combination therapy) and compared for the same parameters.

RESULTS

There was no difference in PRA-positive and negative patients in terms of graft failure, acute GVHD and viral infections. Analysis of the PRA-positive group in itself showed that there was also no difference in terms of graft failure and viral infection frequency. The only difference is that acute grade 3 to 4 GVHD was higher in the steroid-only group. The 100-day overall survival was 90.2% and 90.4% for the PRA-positive and negative groups, respectively.

CONCLUSIONS

Different treatment strategies like plasmapheresis, steroid, rituximab, or combination therapies can be used for the desensitization of PRA-positive patients before hematopoietic stem cell transplantation. Patient-specific treatment modality for sensitized patients before transplant can increase the success rate.

Characteristics and Sensitization Risk Factors in Kidney Transplant Wait List Candidates: Panel Reactive Antibodies Status Is Crucial for Successful Kidney Allocation Systems in Turkey

OBJECTIVES

Kidney transplant is the treatment of choice for end-stage renal disease. Because of the insufficient supply of donor organs for transplant, the number of patients on the transplant wait list is increasing. We analyzed demographic and clinical factors including sensitization status of patients on the kidney transplant wait list in our center.

MATERIALS AND METHODS

Patients on the kidney transplant wait list at Ankara University School of Medicine by July 2018 were evaluated. Data on demographics, comorbidities, treatment characteristics, and immunologic properties were collected.

RESULTS

The study included 528 kidney transplant candidates whose mean time on the deceased donor organ wait list was 57 ± 47 months. Enlisted patients were aged 53 ± 13 years, and 95% of them were on dialysis. Dialysis vintage was longer and percentage of patients who had anti-HLA antibodies was higher in women than men (P = .004 and P < .001, respectively). Levels for median fluorescence intensity were higher in women compared with men (class I, P < .001; and class II, P = .011). Transfusion (P < .001), pregnancy (P = .001), transplant (P < .001), longer dialysis vintage (P = .021), and longer time on wait list (P = .001) were associated with anti-HLA antibody positivity. Multiple regression analysis revealed that a history of transplant and blood transfusion were independent risk factors of a positive panel reactive antibodies.

CONCLUSIONS

In our kidney transplant candidates on the wait list, sensitization by transplant has a significant impact on development of anti-HLA antibodies. Updates of the organ allocation system to consider sensitized candidates and strategies to expand the deceased donor organ pool and donation rates are needed to increase the rate of deceased donor kidney transplant in Turkey.

Perioperative risks of bariatric surgery among patients with and without history of solid organ transplant

Bariatric surgery is effective among patients with previous transplant in limited case series. However, the perioperative safety of bariatric surgery in this patient population is poorly understood. Therefore, we assessed the safety of bariatric surgery among previous-transplant patients using a database that captures >92% of all US bariatric procedures. All primary, laparoscopic sleeve gastrectomy and Roux-en-Y gastric bypass procedures between 2017 and 2018 were identified from the MBSAQIP dataset. Patients with previous transplant (n = 610) were compared with patients without previous transplant (n = 321 447). Primary outcomes were 30 day readmissions, surgical complications, medical complications, and death. Multivariable logistic regression with predictive margins was used to compare outcomes. Previous transplant patients experienced higher incidence of readmissions (8.0% vs 3.5%), surgical complications (5.0% vs 2.7%), and medical complications (4.3% vs 1.5%). There was no difference in incidence of death (0.2% vs 0.1%). Among individual complications, there no statistical differences in intraabdominal leak, unplanned reoperation, myocardial infarction, or infectious complications. Baseline estimated glomerular filtration rate was found to be a strong moderator of primary outcomes, with the highest risk of complications occurring at the lowest baseline estimated glomerular filtration rate. Given the many long-term benefits of bariatric surgery among patients with previous transplant, our findings should not preclude this patient population from operative consideration.

Anti-human Leukocyte Antigen Immune Sensitization Effects of Cryopreserved Allograft and Blood Transfusion

Vascularized composite allotransplantation (VCA) is the most advanced reconstructive technique available to patients who suffer devastating burns to the limbs or face. However, VCA requires donor-recipient matching. Burn patients have been reported to experience sensitization, or the development of anti-human leukocyte antigen antibodies, during resuscitation and wound coverage, potentially precluding them from future VCA. This study sought to investigate the contributions of both blood and allograft to sensitization in burn patients. Four groups were compared: burn patients who received blood products and allograft (group 1), burn patients who received blood products only (group 2), trauma patients who received blood products only (group 3), and healthy volunteer controls (group 4). The average calculated panel-reactive antibody (indicating sensitization) was higher in group 1 compared to group 4 (P = .035). Additionally, the incidence of severe sensitization was higher in group 1 relative to the other groups (P = .049). When comparing groups of patients who had no sensitization, mild sensitization, moderate sensitization, and severe sensitization, there were no significant differences in age, sex, blood products received, total body surface area burned, or allograft used between groups, though severely sensitized patients tended to have greater total body surface area involvement and received more units of packed red blood cells and allograft (P = .079, P = .196, and P = .072, respectively). We therefore conclude that while burn patients who received allograft and blood demonstrated a higher incidence of anti-human leukocyte antigen sensitization relative to healthy controls, this difference cannot solely be attributed to either allograft use or transfusion.

Association of prior sensitizing events with anti-human leukocyte antigen antibodies: An analysis of renal transplant recipients in a tertiary care centre in South India

Traditionally, sensitizing events such as previous pregnancies, previous transfusions and prior transplants result in the production of anti-Human Leukocyte Antigen (HLA) antibodies. However, it has been observed that, anti-HLA antibodies have been detected in many patients with no prior history of sensitizing events. This retrospective study analysed the most recent 100 consecutive Single Antigen Bead (SAB) assay results performed on 100 patients. The SAB assay is used routinely to detect anti-HLA antibodies in transplant recipients. Results of the SAB assay were analyzed and subsequently studied to see if a correlation existed between sensitizing events, the type of events and presence of antibody. Analysis showed that 77% (77/100) had anti-HLA antibodies. 61 out of 100 patients had prior sensitizing events while the remaining 39 had none. Both these groups showed an almost equal percent of patients with anti-HLA antibodies 77% (47/61) and 76.9% (30/39) respectively. A single sensitizing event was seen in 54.1% (33/61) patients including previous transfusions in 29.5% (18/61), pregnancies in 11.4% (7/61) and prior transplant in 13.1% (8/61). Our study suggests that irrespective of whether patients have prior sensitizing events or not, patients run the risks of alloimmunization, and therefore appropriate screening tests should be included in the pre-transplant compatibility algorithm.

Anti-HLA Class II Antibodies Correlate with C-Reactive Protein Levels in Patients with Rheumatoid Arthritis Associated with Interstitial Lung Disease

The pathogenesis of Rheumatoid Arthritis (RA) is not fully understood, probably influenced by genetic and environmental factors. Interstitial Lung Disease (ILD) is an extra-articular manifestation of RA, which contributes significantly to morbidity and mortality. The identification of anti-HLA antibodies has been useful in the transplantation field; however, its contribution to autoimmune diseases as RA has not been fully studied. We aimed to determine the presence of anti-HLA antibodies in RA patients with and without ILD and its possible association with clinical and biochemical markers. One-hundred and forty-seven RA patients, of which 65 had ILD (RA-ILD group), were included. Sera samples for Anti-HLA Class II LABScreen panel-reactive antibodies (PRA) were analyzed. In both groups, women predominated, and lung function was worse in patients with ILD. The anti-CCP+ (UI/mL) was higher in the RA group in comparison to RA-ILD (p < 0.001). Expositional risk factors (tobacco smoking and biomass-burning smoke) were higher in RA-ILD patients. PRA+ was identified in ~25% RA-ILD patients, while ~29% in the RA group. The CRP levels have a positive correlation with the percentage of reactivity (%PRA, p = 0.02, r² = 0.60) in the RA-ILD group. In conclusion, anti-HLA antibodies correlate with C-reactive protein levels in RA patients with ILD.

Prevalence and risk factors of having antibodies to class I and II human leukocyte antigens in older haploidentical allograft candidates

The effect of donor-specific anti-human leukocyte antigen (HLA) antibodies (DSAs) has been recognized as a factor in graft failure (GF) in patients who underwent umbilical cord blood transplantation (UBT), matched unrelated donor transplantation (MUDT), or haploidentical stem cell transplantation (haplo-SCT). Presently, we know little about the prevalence of and risk factors for having anti-HLA antibodies among older transplant candidates. Therefore, we analyzed 273 older patients with hematologic disease who were waiting for haplo-SCT. Among all patients, 73 (26.7%) patients had a positive panel-reactive antibody (PRA) result for class I, 38 (13.9%) for class II, and 32 (11.7%) for both. Multivariate analysis showed that females were at a higher risk for having a PRA result for class II (P = 0.001) and for having antibodies against HLA-C and HLA-DQ. Prior pregnancy was a risk factor for having a PRA result for class I (P < 0.001) and for having antibodies against HLA-A, HLA-B and HLA-DQ. Platelet transfusions were risk factors for the following: having a positive PRA result for class I (P = 0.014) and class II (P < 0.001); having antibodies against HLA-A, HLA-B, HLA-C, HLA-DP, HLA-DQ, and HLA-DR; and having higher mean fluorescence intensity (MFI) of PRA for class I (P = 0.042). In addition, previous total transfusions were at high risk for having higher numbers of antibodies to specific HLA loci (P = 0.005), and disease course (7.5 months or more) (P = 0.020) were related to higher MFI of PRAs for class I. Our findings indicated that female sex, prior pregnancy, platelet transfusions and disease courses are independent risk factors for older patients with hematologic disease for having anti-HLA antibodies, which could guide anti-HLA antibody monitoring and be helpful for donor selection.

Pretransplant Kinetics of Anti-HLA Antibodies in Patients on the Waiting List for Kidney Transplantation

BACKGROUND

Patients on organ transplant waiting lists are evaluated for preexisting alloimmunity to minimize episodes of acute and chronic rejection by regularly monitoring for changes in alloimmune status. There are few studies on how alloimmunity changes over time in patients on kidney allograft waiting lists, and an apparent lack of research-based evidence supporting currently used monitoring intervals.

METHODS

To investigate the dynamics of alloimmune responses directed at HLA antigens, we retrospectively evaluated data on anti-HLA antibodies measured by the single-antigen bead assay from 627 waitlisted patients who subsequently received a kidney transplant at University Hospital Zurich, Switzerland, between 2008 and 2017. Our analysis focused on a filtered dataset comprising 467 patients who had at least two assay measurements.

RESULTS

Within the filtered dataset, we analyzed potential changes in mean fluorescence intensity values (reflecting bound anti-HLA antibodies) between consecutive measurements for individual patients in relation to the time interval between measurements. Using multiple approaches, we found no correlation between these two factors. However, when we stratified the dataset on the basis of documented previous immunizing events (transplant, pregnancy, or transfusion), we found significant differences in the magnitude of change in alloimmune status, especially among patients with a previous transplant versus patients without such a history. Further efforts to cluster patients according to statistical properties related to alloimmune status kinetics were unsuccessful, indicating considerable complexity in individual variability.

CONCLUSIONS

Alloimmune kinetics in patients on a kidney transplant waiting list do not appear to be related to the interval between measurements, but are instead associated with alloimmunization history. This suggests that an individualized strategy for alloimmune status monitoring may be preferable to currently used intervals.

Heart Failure in Adult Congenital Heart Disease: From Advanced Therapies to End-of-Life Care

There is mounting recognition that some of the most urgent problems of adult congenital heart disease (ACHD) are the prevention, diagnosis, and management of heart failure (HF). Recent expert consensus and position statements not only emphasize a specific and pressing need to tackle HF in ACHD (ACHD-HF) but also highlight the difficulty of doing so given a current sparsity of data. Some of the challenges will be addressed by this review. The authors are from 3 different centres; each centre has an established subspeciality ACHD-HF clinic and is able to provide heart transplant, multiorgan transplant, and mechanical support for patients with ACHD. Appropriate care of this complex population requires multidisciplinary ACHD-HF teams evaluate all possible treatment options. The risks and benefits of nontransplant ACHD surgery, percutaneous structural and electrophysiological intervention, and ongoing conservative management must be considered alongside those of transplant strategies. In our approach, advanced care planning and palliative care coexist with the consideration of advanced therapies. An ethos of shared decision making, guided by the patient's values and preferences, strengthens clinical care, but requires investment of time as well as skilled communication. In this review, we aim to offer practical real-world advice for managing these patients, supported by scientific data where it exists.

Opportunistic parasitoses among Egyptian hemodialysis patients in relation to CD4+ T-cell counts: a comparative study

Background

Some reports are available on the prevalence of opportunistic parasitoses among hemodialysis (HD) patients, yet there is a paucity of data on the association of CD4+ T-cell counts with such infections. Therefore, this study aimed to determine the prevalence of intestinal parasites and Toxoplasma gondii in relation to CD4+ counts among HD patients in Alexandria, Egypt.

Methods

A comparative cross-sectional study was conducted on 120 HD patients and 100 apparently healthy individuals between December 2014 and January 2016. Data and samples (stool and blood) were collected from the participants after obtaining their informed consent. Stool samples were examined for parasites after concentration and staining, EDTA-blood samples were used for CD4+ counting by flow cytometry, and sera were analyzed for anti-Toxoplasma IgM and IgG antibodies.

Results

A significantly higher prevalence rate of intestinal parasitoses was found among HD patients compared to apparently healthy individuals (52.5% vs. 12.0%, respectively), with absence of helminths. Cryptosporidium species (32.5%), B. hominis(24.2%) and microsporidia (11.7%) were the most frequent parasites among HD patients, while B. hominis (13.0%), Cryptosporidium species (11.0%) and G. lamblia (4.0%) were the most frequent parasites among their counterparts. Statistically significant differences in parasite infection rates between patients and their counterparts were found for Cryptosporidium species, B. hominis and microsporidia. However, parasite species were not significantly associated with diarrhea. On the other hand, the overall T. gondii seroprevalence rate among HD patients was significantly higher than that among their counterparts (33.3% vs. 8%, respectively). HD patients with CD4+ counts < 200 cells/μl were twice more exposed to intestinal parasitoses compared to those with counts ≥200 cells/μl, but the difference was not statistically significant. However, low CD4+ counts were significantly associated with higher rates of Cryptosporidium species, microsporidia and T. gondii.

Conclusions

Intestinal parasitoses and T. gondii infection rates are significantly higher among Egyptian HD patients compared to apparently healthy individuals, with Cryptosporidium species, B. hominis, microsporidia and T. gondii being the most frequent parasites. CD4+ counts < 200 cells/μl are significantly associated with Cryptosporidium species, microsporidia and T. gondii among HD patients. Therefore, regular screening of HD patients for opportunistic parasites is recommended.

Pretransplant Immune Interplay Between Donor and Recipient Influences Posttransplant Kidney Allograft Function

BACKGROUND

Renal transplant candidates present immune dysregulation caused by chronic uremia, and deceased kidney donors present immune activation induced by brain death. Pretransplant donor and recipient immune-related gene expression were examined in the search for novel predictive biomarkers crosslinking recipient and donor pretransplant immune status with transplant outcome.

MATERIALS AND METHODS

This study included 33 low-risk consecutive renal transplant recipients and matched deceased donors. The expression of 29 genes linked to tissue injury, T-cell activation, cell migration, and apoptosis were assessed in postreperfusion kidney biopsies, as well as 14 genes in pretransplant peripheral blood of the kidney recipients. Gene expression was analyzed with real-time polymerase chain reaction on custom-designed low-density arrays.

RESULTS

Donor MMP9 expression was related to delayed graft function occurrence (P = .036) and short term kidney allograft function (14th day r_s = -0.44, P = .012; 1st month r_s = -0.46, P = .013). Donor TGFB1 expression was associated with short- and long-term graft function (14th day r_s = -0.47, P = .007; 3rd month r_s = -0.63, P = .001; 6th month r_s = -0.52, P = .010; 12th month r_s = -0.45, P = .028; 24th month r_s = -0.64, P = .003). Donor TGFB1 expression was not related to donor age (r_s = 0.32, P = .081), which was also an independent factor influencing the outcome. Recipient gene expression was not related to graft function but determined the acute rejection risk. Recipient IFNG and, to a lesser extent, IL18 expression were protective against acute rejection (area under the curve [AUC] 0.84, P < .001, and AUC 0.79, P < .001, respectively).

CONCLUSION

Kidney transplant outcome depends on the interplay between donor-related immune factors, which mostly affect allograft function and recipient immune milieu, influencing an alloreactive response.

Kidney Transplantation: The Challenge of Human Leukocyte Antigen and Its Therapeutic Strategies

Kidney transplantation remains the treatment of choice for end-stage renal failure. When the immune system of the recipient recognizes the transplanted kidney as a foreign object, graft rejection occurs. As part of the host immune defense mechanism, human leukocyte antigen (HLA) is a major challenge for graft rejection in transplantation therapy. The impact of HLA mismatches between the donor and the potential recipient prolongs the time for renal transplantation therapy, tethered to dialysis, latter reduces graft survival, and increases mortality. The formation of pretransplant alloantibodies against HLA class I and II molecules can be sensitized through exposures to blood transfusions, prior transplants, and pregnancy. These preformed HLA antibodies are associated with rejection in kidney transplantation. On the other hand, the development of de novo antibodies may increase the risk for acute and chronic rejections. Allograft rejection results from a complex interplay involving both the innate and the adaptive immune systems. Thus, further insights into the mechanisms of tissue rejection and the risk of HLA sensitization is crucial in developing new therapies that may blunt the immune system against transplanted organs. Therefore, the purpose of this review is to highlight facts about HLA and its sensitization, various mechanisms of allograft rejection, the current immunosuppressive approaches, and the directions for future therapy.