The Algerian Experience in Enhancing Kidney Transplant Safety and Eligibility via Combined Crossmatch Techniques

Crossmatch testing detects donor-specific anti -HLA antibodies to stratify immunological risk before living -donor kidney transplant, preventing antibody -mediated rejection. This study optimized a tiered strategy combining complement -dependent cytotoxicity, flow cytometry, and Luminex single antigen assays for precise pathogenicity assessment of donor -specific antibodies in resource -constrained Algerian centers lacking routine deceased -donor programs.

This prospective ongoing study (initiated in 2021 ) enrolled 90 sensitized patients (mean age 35 years; range, 9 -61 years; sex ratio: 0.6 ) at Bab El Oued and Batna University Hospitals. Sensitizing events included transfusions (41 %), pregnancy (13 % ), prior transplant (6 % ), and unknown (40 % ). Full 3 -assay stratification was applied to 45 patients: category 1 (all positive tests ) were excluded from transplant; category 2 (negative complement -dependent cytotoxicity crossmatch /positive flow cytometry crossmatch /positive Luminex single antigen assay ) underwent desensitization to achieve negative flow cytometry crossmatch; category 3 (negative complement -dependent cytotoxicity crossmatch/negative flow cytometry crossmatch /positive Luminex single antigen assay ) were subdivided into categories 3a (Luminex single antigen mean fluorescence intensity >3000, preventive desensitization ) and 3b (mean fluorescence intensity <3000, direct transplant ); and category 4 (all assays negative ).

Stratification was as follows: 1 patient in category 1, 4 patients in category 2 (1 transplanted after desensitization, others ongoing ), 9 patients in category 3a, 24 patients in category 3b, and 7 patients in category 4. Of 31 transplanted patients, 90 % reached 3 -month and 60 % reached 12 -month follow -up, with mean serum creatinine of 1.4 mg /dL. Donor -specific antibody cleared in 80 % (category 3b ); 20 % had persistent low mean fluorescence intensity donor-specific antibodies. No patients had acute antibody-mediated rejection on 12 -month protocol biopsies.

Integrated crossmatch assays enabled safe transplant in 84 % (categories 3b /4 ), reducing desensitization needs amid absent deceased -donor programs and rare paired exchange.