P1583: TRANSFUSIONS IN AUTOIMMUNE HEMOLYTIC ANEMIA: FREQUENCY AND CLINICAL SIGNIFICANCE OF ALLOIMMUNIZATION

• DOI: 10.1097/01.hs9.0000973208.19974.a4
• Publication Date: 2023-08-09T03:03:59Z
• Authors: Francesco Versino; Nicoletta Revelli; Stefania Villa; Loredana Pettine; Anna Zaninoni; Daniele Prati; Wilma Barcellini; Bruno Fattizzo
• Keywords: Coombs test; Transfusion medicine; Single Center

Topic: 31. Transfusion medicine Background: Autoimmune hemolytic anemia (AIHA) is a rare and heterogeneous disease, ranging from mild to very severe forms; the latter may present acutely require transfusion support. There are several concerns regarding risk of reactions alloimmunization, reported in about 1/3 cases historical series. However, data on their clinical impact lacking, especially considering evolving blood selection strategies last decades. Aims: To evaluate policy rate alloimmunization patients with AIHA. Methods: 103 AIHA who received at least one transfusion, series 408 followed single center Milan Italy 1997 2022, were included. Patients classified as warm (wAIHA), cold (cAIHA), mixed or atypical (negative direct antiglobulin test, DAT, IgA positive AIHA). Clinical laboratory features, indirect test (IAT), auto alloantibody specificity retrospectively registered. Number red cell (RBC) transfusions, hematologic parameters pre post well recorded. Results: We included median age 62 years (19-94), slight female predominance, follow up 64 months (range 1-305). Most diagnosed wAIHA (54%), by cAIHA (33%) mixed/atypical (13%). The number RBC units (RBCU) transfused was 4 (1 – 55, two heavily due subsequent diagnosis myelodysplasia). Median pre-transfusion Hb 6.8 g/dL (2.7-8.6), LDH 441U/L (125-2875), reticulocytes 153x10^9/L (3-354). Eight febrile (7%) registered, none hemolytic. Figure 1 depicts trend frequency among along time: transfusions progressively decreased 53% 20% over time, particularly after 2010. Moreover, steadily gradually dropping 30% 6%. Overall, anti-RBC alloantibodies found 20 (19%). showed higher burden compared non-alloimmunized (median 10 vs 3 RBCU, p = 0.01). Furthermore, they lower increase [0.9 (0.2 3.5) 1.5 (0 - 7.1) g/dL, 0.05]. This even more significant for those before 2010 [0.7 -1.7) 1.8 (0.4 4.5) p=0.03] but not decade (> 2010), possibly improved quality unit allocation. Notably, alloimmunized group had significantly (20 4%, 0.04). Relapsed/refractory also increased [median relapses allo patients: [2 (0-13) (0-8), Finally, similar distribution sex, age, type ABORh noted. Summary/Conclusion: These show that lead 1g/dL Hb, generally safe, less than 10% experiencing reactions. frequent subjects developing alloantibodies, reduced increase. we observed decrease decades, likely linked adoption pre-storage leukoreduction, use restrictive thresholds, implementation molecular typing donors.Keywords: Blood (AIHA), outcome, Antibody