Clinical Heterogeneity Of Autoimmune Hemolytic Anemia: A 35-Years Retrospective Study Of 157 Patients

The clinical presentation of autoimmune hemolytic anemia (AIHA) is greatly heterogeneous, from mild/compensated to life-threatening forms. The aim of this study was to correlate the clinical and serological characteristics of the disease, usually classified as warm (WAIHA), cold (CHD), and mixed, based on the thermal and isotype characteristics of the anti-RBC antibody (IgG, IgM or both, respectively). One-hundred fifty seven AIHA patients (61 M and 96 F, median age 57, range 5-95) referred to our institution from 1978 to September 2012 were investigated. They had been followed-up for a median of 26 months (range 12-271), and 50% were still in follow-up. As regards the thermal characteristics 40% of cases were WAIHA, 32% CHD, 19% mixed forms and 9% atypical (12 DAT negative and 1 DAT positive for IgA only). Considering the severity of anemia at onset 33% of cases had Hb levels<6 g/dl, 34% Hb 6-8 g/dL, 18% Hb 8-10 g/dL, and 15% Hb>10 g/dL. The most severe AIHA cases were mainly mixed (18/30, 60% p=0.001) and atypical (6/13, 46%) forms, whereas only a small fraction of CHD was characterized by a severe onset (8/51, 16% p=0.002). Reticulocytopenia (<100.000 mmc) was more frequently observed in cases with severe onset (14/52, 27%), possibly contributing to the clinical picture. Eleven patients experienced an acute event at the onset of hemolysis and the majority of them (7/11, 63% ) were WAIHA; we recorded 4 deep venous thrombosis (with 2 subsequent pulmonary embolisms), 1 disseminated intravascular coagulation, 3 cardiac ischemic events, 2 acute renal failure and 4 acute infection (3 pneumonias and 1 sepsis); 18 patients died because of AIHA during the follow up. As regard therapy, we considered steroids, splenectomy, cytotoxic drugs and rituximab: 45% of cases (mostly WAIHA) were treated with steroids only, 23% with 2 lines, 10% with 3, and 6% with 4 or more lines; splenectomy was performed in 20 cases, mostly mixed and severe forms (p=0.001); 23 patients were treated with various cytotoxic drugs, and 33 with rituximab (the latter was more frequently administered in clinically severe cases, and in mixed and atypical forms, p=0.009). On the whole, the most severe patients were those who underwent 3 or more lines of therapy, compared with the other cases (14/52 versus 11/105, p=0.015). Finally, 16% of cases have never been treated, mostly CHD with mild anemia. Transfusions were performed in 65 cases, plasma-exchange in 3 (all with Hb<6 g/dL), and erythropoietin administered in 6 cases. Of note, the presence of an Hb value lower than 6 g/dL at onset was a risk factor for the requirement of 3 or more lines of therapy (odds ratio 3.148, CI 95% 1.312-7.552). Response rates to steroid therapy were similar in warm, cold, mixed and atypical AIHAs (on average 70%). Responses to rituximab were similar in cold and other AIHA forms (70-80%). Splenectomy, was ineffective in the 2 CHD who underwent surgery, whereas response rates were 63% in WAIHA and 80% in mixed and atypical cases. In conclusion, AIHAs showed a marked clinical heterogeneity, 1/3 of cases with a severe onset and with life threatening complications. These cases are frequently mixed or atypical forms and refractory to different therapies.