Retrospective and Prospective Study of Childhood Autoimmune Hemolytic Anemia. a Preliminary Report from the Red Cell Working Group of the Paediatric Hemato-Oncology Italian Associations (AIEOP)
Authors: Ladogana Saverio , Colombatti Raffaella , Perrotta Silverio , Maggio Angela , Maruzzi Matteo , Ciliberti Andrea , Samperi Piera , Casale Maddalena , Giordano Paola , Del Vecchio Giovanni Carlo , Perillo Teresa , Boscarol Gianluca , Notarangelo Lucia Dora , Casini Tommaso , Miano Maurizio , Fasoli Silvia , Paola Corti , Guarina Angela , Arcioni Francesco , Sau Antonella , Giona Fiorina , Palumbo Giuseppe , Saracco Paola , Petrone Angela , Verzegnassi Federico , Piccolo Chiara , Cesaro Simone , Russo Giovanna 
Published: February 2020

Autoimmune hemolytic anemia (AIHA) is an uncommon disease of childhood caused by the premature destruction of erythrocytes by autoantibodies. In this rare disease both diagnostic criteria and therapeutic approaches are not well standardized. The Red Cell Working Group of the Pediatric Italian Hematogy and Oncology Association (AIEOP) developed specific recommendations to help Physicians for AIHA management. The document is available on the AIEOP website since November 1st 2013.
The Italian Pediatric AIHA Group began an observational, retrospective and prospective study in order to monitor the management of children with AIHA diagnosed from 2010 to 2018, and to assess whether the availability of AIEOP recommendations had an impact on the clinical management of such patients in AIEOP Centers.
We collected a national cohort of 159 children with AIHA from 21 AIEOP Centers; 48 patients were diagnosed before November 2013 and 111 patients after that date.
Gender was 56% males and 44% females; median age at diagnosis was 47 months, with 11.9% under 12 months of age; 8.2% of children were born prematurely and 3.9% showed congenital malformations. 23.2 % of patients had a familiar history of immunological, hematological or oncological diseases.
The median hemoglobin level at diagnosis was 6.1 gr/dL.
Table 1 reports the distribution of our cases, according to the different type of autoantibodies.
The comparison between the retrospective and prospective study did not reveal significative differences in clinical and biological presentation.
The cold IgM forms were mainly post infective (38.4%) or primary forms (53.8%), only one patient had a secondary form due to a primitive immunodeficiency. These patients did not develop other diseases during follow up (median follow up: 28,6 months).
The preliminary results of treatment and follow up of the 146 patients with warm antibody AIHA revealed the following:
The treatment with conventional dose of steroids (median dose 2 mg/Kg, range 0.7- 3.5 mg/Kg) was started in 94.4% of patients, in 53% of cases on the same day of diagnosis.
A high number of children used additional treatment: red blood cell transfusions (51.4%), high dose Prednisolone (59.7%), high dose i.v. Immunoglobulin (49.7%) and Plasma Exchange (1.4%).
9.5% of patients, with poor responsive disease, needed alternative drugs during the first four weeks of therapy.
Response criteria were so defined: a complete response was defined as the achievement of an Hb concentration greater than or equal to the lower normal limit for age with no signs of haemolysis, i.e. normal reticulocyte count and bilirubine concentration. A partial response was defined as an increase of Hb &gt;2 g/dL without the Hb concentration reaching a normal value for the patient age and no response as an increase of Hb&lt; 2 g/dL and/or dependence on transfusion.
A complete response was reached by 62.5%, 79.3%, 85.1% at 3, 4, 6 weeks respectively.
14.9% of patients had either a partial response or a resistant disease at 6 weeks.
IgG/IgG+C3d positivity was a negative prognostic factor, as compared to positivity to C3d only, with the need of a second line treatment (prevalently Mabthera or Mycophenolate Mofetil) in 31.7% vs 0, respectively (p 0.009).
Currently 6.1% of the patients were lost to follow up, 1.3% died, 55,8% are in Complete Response without events and 21.9% of the patients are still on treatment .
At the last follow up, in the whole "cohort" of warm AIHA, 58% have a Primary form, 15.7% an isolated post infective form and 27.7% a Secondary form (56% Evans Syndrome).
The management of the patients diagnosed after November 2013 was mostly in agreement with our recommendations, whose comprehensive therapeutic algorithm is reported in table 2, with prolonged steroid tapering in order to extend the treatment for at least 6 months. The most important difference between the retrospective and prospective study was the duration of first line treatment: 6 months or more, for steroid dependence, in 71.6% of patients in the prospective study versus 52.3% of the retrospective (p 0.031) and, more importantly, the percentage of relapsed patients: 8.3% in the prospective study versus 29.8% of the retrospective (p 0.001), these data need a longer follow up (median follow up: 24 months in the prospective study versus 63 in the retrospective)

Disclosures
Colombatti: Global Blood Therapeutics: Consultancy; Novartis: Consultancy; AddMedica: Consultancy.