RESUMO
Nephrogenic adenoma is a rare lesion that consists of epithelial cells arranged in tubular form, resembling tubules in the renal medulla, and is found usually in the urinary bladder although it can occur anywhere in the transitional epithelium of the lower urinary tract. The first case of nephrogenic adenoma of the urinary bladder was reported before the first kidney transplantation, and the lesion has been reported in patients with and without renal transplantation. The origin of cells in nephrogenic adenoma is debated and has been postulated to arise from cells of embryonic origin or from metaplasia secondary to chronic irritation or from implantation of allograft cells in patients with kidney transplantation. The long-term outcome and potential to convert into malignancy are not established, and therefore, there are no recommendations on how to follow up these patients. We present a case of a patient who was found to have nephrogenic adenoma of the urinary bladder during his second kidney transplantation from a cadaveric donor. He had undergone living donor kidney transplantation previously which subsequently failed. The patient did not manifest any symptoms of nephrogenic adenoma. During a follow-up period of 5 years, he has not manifested any symptoms related to nephrogenic metaplasia. Histopathological examination 5 years after the second transplantation did not show any malignant change. It can be concluded that nephrogenic adenoma is likely to behave in benign fashion post kidney transplantation.
RESUMO
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. However, it is becoming clear that the detection of the HLA antibodies by SAB is not absolutely perfect due to the variation in densities, conformations and orientations of the antigen coated beads. Unlike HLA-DR, the HLA-DQ antigens are made of two polymorphic chains, both (alpha and beta chains) can contribute to the process of immunization individually or jointly. Routine SAB testing approach, which assigns the specificities based on beta chains and ignores the contribution of the DQα chains, can lead to erroneous DQ-antibody assignments. Therefore, it is important to recognize both the peculiarity of the HLA-DQ antigens as well as the nature of the assay format used in order to reach the correct antibody assignments. Erroneous donor specific antibodies (DSA) assignment may lead to denial of an otherwise immunologically compatible organ transplant, or exposing transplant recipients to unnecessary investigations or immunosuppression. The following two patients presented with HLA-antibodies against DQ antigens (anti-DQ-Abs) highlight these two scenarios.