Objective: To analyze the causes and distribution characteristics of leukopenia in apheresis platelet donors, and to formulate effective pre-donation intervention measures. Methods: The data of apheresis platelet donors with leukopenia in Dongguan Central Blood Station during the entire year of 2021 were collected. Combined with the results of peripheral blood smear examination, the related factors that may cause leukopenia were analyzed. Results: There were 57 apheresis platelet donors with leukopenia in peripheral blood, with an incidence of 1.53% (57/3 726). The rate of leukopenia showed no significant difference between male and female apheresis platelet donors (χ =0.627, P>0.05), and was not related to the frequency of platelet donation (χ =1.48, P>0.05). However, there were statistically significant differences in the rate of leukopenia across seasons (χ =10.13, P<0.05), highly significant differences among different age groups (χ =22.98, P<0.001), and a significant association with the number of apheresis platelet donations (χ =7.80, P<0.05). Multivariate logistic regression analysis showed that age (36-55 years old), number of donations (≥26 times), and season (first and fourth quarters) were independent risk factors for leukopenia in apheresis platelet donors, while gender had no significant independent effect on leukopenia. Peripheral blood smear examination was performed on all apheresis platelet donors with leukopenia, and primary malignant hematological diseases infiltrated into peripheral blood were excluded. Among them, two cases of peripheral blood smear showed left shift of granulocyte nucleus with increased and thickened granules, whereas the other 55 cases only showed decreased peripheral blood nucleated cell counts without obvious morphological abnormalities. Conclusion: Leukopenia in apheresis platelet donors mainly occurred in young and middle-aged people and those with ≥26 donations, with high incidence in winter and spring, and more common in males. Blood routine examination combined with blood smear examination can facilitate the detection of conditions that are not suitable for blood donation, including hematological malignant diseases and infection-related leukopenia. Strengthening health consultation before blood donation is an important measure to identify blood donors with leukopenia.

Objective: To identify the mimicking autoantibodies using papain-enhanced erythrocyte agglutination in a case of repeated red blood cell transfusion refractoriness, aiming to explore the immune hematological methods for identifying mimicking alloantibodies, autoantibodies and alloantibodies, and to develop a safe and effective blood transfusion strategy based on the results. Methods: ABO, RhD and RhEeCc blood groups were detected using routine blood group serological method. The unexpected antibodies in plasma were screened and identified, followed by identification using a two-step papain-treated indirect antiglobulin test (enzyme-IAT). The cause of transfusion refractoriness of red blood cells was analyzed and summarized, and the prognosis was followed up. Results: The patient's blood type was type A, CCDee. The direct antiglobulin test (DAT) was positive. Unexpected antibody screening and identification using saline tube method, polybrene method, IAT were negative, and the release fluid (acid release) IAT identification was negative. Mimicking anti-e antibodies in plasma was identified by enzyme-ITA. The cause of red blood cell transfusion refractoriness in patients was autoimmune hemolysis caused by mimicking anti-e antibodies. After choosing to avoid antibodies corresponding to antigen-positive red blood cells, the patient's hemoglobin (Hb) increase value is in line with theoretical expectations, indicating effective red blood cell transfusion. Conclusion: Mimicking antibodies can cause immune destruction of red blood cells by non-specific binding to their own red blood cells and specific binding to red blood cells, resulting in red blood cell transfusion refractoriness.