The humoral immune response to the BNT 162B2 vaccine in pediatrics on renal replacement therapy.

Introduction: Since the start of the COVID-19 pandemic, data published on the immunogenicity of the SARS-CoV-2 BNT 162B2 vaccine in pediatric patients receiving renal replacement therapy are scant. Our primary objective is to study this population's humoral immune response to the COVID-19 vaccine.

Methods: Pediatric kidney transplant recipients (PKTRs) and hemodialysis recipients (HR) at our center who received two doses of the SARS-CoV-2 BNT 162B2 vaccine were included.

Impact of COVID-19 pandemic on transplant laboratories: How to mitigate?

A positive flow cytometry crossmatch (FCXM) due to donor specific antibodies (DSA) constitutes a risk for kidney transplantation; such a finding may indicates an unacceptable donor for this patient. However, positive FCXM in the absence of DSA is considered discordant and need further investigations. During COVID-19 pandemic, we observed 22% discordant results out of 445 FCXM performed during eight months period in our laboratory and another 7% were invalid due to high background negative control (NC).

Severe delayed graft function in a living-related kidney transplant recipient due to combination of alloimmunity, autoimmunity, and heterologous immunity: A case report.

Background: Delayed graft function is a manifestation of acute kidney injury unique to transplantation usually related to donor ischemia or recipient immunological causes. Ischemia also considered the most important trigger for innate immunity activation and production of non-HLA antibodies. While ischemia is inevitable after deceased donor transplantation, this complication is rare after living transplantation.

Detection of SARS-CoV-2 antibodies in pediatric kidney transplant patients.

Background: The seroprevalence of SARS-CoV-2 infection has been studied in immunocompetent children. However, data in the pediatric kidney transplant population (PKT) are lacking.

Methods: Using two commercial immunoassays that measured IgG antibodies against SARS-CoV-2 spike protein and IgG against the nucleocapsid (N) protein, we screened 72 PKT recipients who attended the outpatient clinic for routine blood work.

The novel allele, HLA-A*32:148, identified by next generation sequencing in a Saudi individual.

A single nucleotide substitution in exon 4 of HLA-A*32:01:01:01 results in novel HLA-A*32:148 allele.

Discrepant Antibody Testing Results: Which One to Believe?

The impact of solid-phase immunoassay for HLA antibody detection on the field of transplantation has been extremely significant by providing the most sensitive and precise method for characterization of HLA antibodies. However, despite all the benefits, technical limitations and inherent artifacts represent significant challenges, particularly with Luminex-based single-antigen bead (SAB) assay. Discordant results between antibody detection (screening assay) and identification (SAB) is not uncommon.

The dilemma of DQ HLA-antibodies.

Accurate identification of antibody reactivity against HLA-DQ antigens was difficult by using the old serological assays because of the strong linkage disequilibrium between HLA-DR and HLA-DQ (the usual inheritance of a certain HLA-DR molecule that ties together with the same DQ molecule within a racial group). The accurate and precise identifications of anti-HLA-antibodies of DQ specificities were made possible with the introduction of multiplex-bead arrays (Luminex), using single antigen bead (SAB) assay. The SAB assay is also considered today to be the most sensitive and specific method for alloimmunization assessment even for the low titer anti-HLA-antibodies.

How common is celiac disease in Eastern Saudi Arabia?

Background: In contrast to its prevalence in Europe, celiac disease (CD) is considered rare in non-Caucasian populations. We aimed to estimate the prevalence of CD in clinically suspicious celiac disease patients and in patients with disorders known to be associated with CD, such as autoimmune diseases, using serological assay for IgA-endomysial antibodies (EMA) on inexpensive human tissue substrate.

Patients And Methods: IgA-endomysial and IgA-reticulin antibodies (ARA) were evaluated by indirect immunofluorescence (IIF) study using human umbilical cord (HUC) and rat tissues, respectively, in the following groups: group 1, 145 patients with clinical suspicion of CD; group 2, 80 with autoimmune diseases; group 3, 20 patients with inflammatory bowel disease (IBD); and group 4, 100 healthy blood donors.