Determination of the percentage of pra positivity in male patients with chronic kidney disease by using flow cytometry technique

Kidney transplantation is the most effective treatment method for the end-stage renal disease. The antibodies directed against HLA molecules, which play a crucial role in allograft histocompatibility, are called anti-HLA antibodies. Anti-HLA antibodies against foreign HLA molecules may be present in patients with chronic kidney disease even before transplantation. PRA test is routinely used in patients waiting for kidney transplantation in order to assess their immunological sensitivity to foreign HLA molecules and to evaluate the diversity of the anti-HLA antibodies in their blood, along with the level of this diversty. Multipara pregnancies, previously allograft transplantations and blood transfusions are the major known causes that make PRA test positive. Apart from these, anti-HLA antibodies may also be detected in male patients who have not received any blood transfusion or organ transplant before. And these anti-HLA antibodies are thought to occur against cross-reactive epitopes found on microorganisms and allergens. There are limited number of studies about the PRA levels in patients undergoing dialysis or in patients who have chronic kidney disease in Turkey. In this study, it is aimed to determine the PRA values and the percentage of PRA positivity of the Turkish male patients with chronic kidney disease, who have not been sensitized by the major known causes (those with no history of organ or tissue transplantation, those with no history of blood transfusion), who have not been diagnosed with any autoimmune diseases and who have not been under immunosuppressive treatment. The study included 60 male patients, who have chronic kidney disease, who have not been sensitized by major known causes (those with no history of organ or tissue transplantation, those with no history of blood transfusion), who have not been diagnosed with any autoimmune diseases and who have not been under immunosuppressive treatment. All the patients were over 18 years old. 20 of the all patients were receiving dialysis treatment due to end-stage renal disease. The percentages of the PRA levels were detected and analysed by flow cytometry technique to the blood samples of the patients. Of the 60 patients included in the study, 25% showed PRA positivity. 28.3% of the all patients were found to be positive for anti-HLA class I antibodies and 26.7% of the all patients were found to be positive for anti-HLA class II antibodies in the separate analysis for anti-HLA class I and anti-HLA class II antibody positivity. When the patients were categorized as PRA negative and PRA positive in two groups, there were no differences between the groups in terms of mean age, the percentage of hemodialysis patients, the percentage of peritoneal dialysis patients and the presence of accompanying chronic diseases (such as hypertension, type 2 diabetes mellitus, hyperlipidemia, nephrolithiasis, coronary artery disease). In addition to this, the comparison of GFR levels showed that the PRA positive group contained a significantly higher percentage of end-stage renal disease patients (GFR <15 ml/min/1.73 m2) as compared to the PRA negative group. A detailed analysis into the percentages of the PRA levels in the PRA positive patients, which was carried out to determine the degree of sensitization, showed that the PRA values were over 80% in the 11.77% of the patients positive for anti-HLA class I antibodies. The PRA values were below 80% in all of the patients positive for anti-HLA class II antibodies and those positive for both anti-HLA class I and class II antibodies. The intergroup comparisons to investigate any possible factors related with the percentage of the PRA level showed that none of the factors including hemodialysis, peritoneal dialysis, presence of accompanying chronic diseases (hypertension, nephrolithiasis, coronary artery disease, type 2 diabetes mellitus) and GFR levels were related with the percentage of the PRA level. In conclusion, it should be kept in mind that anti-HLA antibodies may be present in patients with chronic kidney disease and transplant candidates with end-stage renal disease, even if they have no history of exposure to any foreign HLA antigens or they have no autoimmune disease. Therefore, panel-reactive antibody levels of the candidates for kidney transplant should always be measured to assess their state of sensitization before transplantation, even though they have no risk factors known to cause anti-HLA antibody development.