[Characteristics of bone marrow compensatory erythropoiesis in hereditary spherocytosis]

Objective: To reveal the compensatory features of bone marrow (BM) erythropoiesis in hereditary spherocytosis (HS) and to explore the effect of diferent hemoglobin levels on this compensation. Methods: Clinical and laboratory data of patients with HS were collected, and the peripheral blood absolute reticulocytes counts value was taken as the surrogate parameter to evaluate the ability of erythropoiesis compensation. BM erythropoiesis compensation in HS with diferent degrees of anemia were evaluated. Results: ①Three hundred and two patients were enrolled, including 115 with compensated hemolytic disease, 74 with mild anemia, 90 with moderate anemia, and 23 with severe anemia. ②Hemoglobin (HGB) was negatively correlated with serum erythropoietin in the decompensated hemolytic anemia group (EPO; rs=-0.585, P<0.001) . ③The median absolute reticulocyte count (ARC) of HS patients was 0.34 (0.27, 0.44) ×10(12)/L, up to 4.25 times that of normal people. The maximum ARC was 0.81×10(12)/L, about 10 times that of normal people. The median ARC of patients with compensated hemolytic disease was 0.29 (0.22, 0.38) ×10(12)/L, up to 3.63 times that of normal people. The median ARC of patients with hemolytic anemia was 0.38 (0.30, 0.46) ×10(12)/L, which was significantly higher than the patients with compensated hemolytic disease, up to 4.75 times that of normal people (z=4.999, P=0.003) . ④ ARC was negatively correlated with HGB in the compensated hemolytic disease group (rs=-0.177, P=0.002) and positively correlated with HGB in the decompensated hemolytic anemia group (rs=0.191, P=0.009) . There was no significant difference in the ARC among patients with mild, moderate, and severe anemia (χ(2)=4.588, P=0.101) . ⑤The median immature reticulocyte production index of the mild, moderate, and severe anemia groups was 13.1% (9.1%, 18.4%) , 17.0% (13.4%, 20.8%) , and 17.8% (14.6%, 21.8%) , respectively; the mild anemia group had lower index values than the moderate and severe anemia groups (P(adj) values were both<0.05) , but there was no significant difference between the latter groups (P(adj)=1.000) . The median immature reticulocyte count of patients in the mild, moderate, and severe groups was 5.09 (2.60, 7.74) ×10(10)/L, 6.24 (4.34, 8.83) ×10(10)/L, and 7.00 (3.07, 8.22) ×10(10)/L, respectively; there was no significant difference among the groups (χ(2)=3.081, P=0.214) . Conclusion: HGB can be maintained at a normal level through bone marrow erythropoiesis, while red blood cells are reduced in HS. However, once anemia develops, the bone marrow exerts its maximum erythropoiesis capacity and does not increase, regardless of anemia aggravation or serum EPO increase.