Department of Pediatric, Azadi Teaching Hospital, Kirkuk, Iraq


Background: Inhibitor formation is a major complication of hemophilia treatment that interferes with clinical response to factor infusion and results in significant morbidity. It is estimated to occur in up to (15–25%) of hemophilia A patients treated with factor VIII. 
Aim of the study: The objective of this study is to assess factors associated with inhibitor development in patients less than15 year old with hemophilia A in children welfare teaching hospital in medical city/ Baghdad. 
Patients and methods: A retrospective descriptive study that had been performed by reviewing patients files & interviewed with those who visited the hemophilia ward in children welfare teaching hospital ,medical city , Baghdad , from the 1st of August 2008 to the 1st of September 2012. Detection of inhibitors was done by mixing study for the (258) patients with hemophilia A less than 15 year old & then Bethesda assay for those with not corrected mixing study. Then data were collected from patients with positive test for inhibitors according to a pre-constructed forma which contained clinical, laboratory finding & treatment regimens. 
Results: it was found that, from (285) hemophilia A treated patients less than 15 year old only (27 ,10.47%) patients had inhibitors, from these; the majority (26) patients (96.3%) of them had severe hemophilia A while one patient (3.7%) had moderate hemophilia A. Twenty two patients (81.5%) were high responders while three patients (11.1%) were low responders. the majority (22 ,81.5%) of our studied patients received blood and blood products transfusion before they developed inhibitor. 
Conclusion: Understanding the environmental (modifiable) risk factors responsible for increased risk of inhibitor development is essential to identify patient’s risk profile and to allow tailoring of treatment on an individual basis (thus reducing inhibitor formation risk and obtaining optimal benefit). Recommendations: The avoidance/minimization of intense FVIII exposure (possibly through early prophylaxis, and furthermore, delayed surgical procedure when possible) during the first year of life. Further research is necessary to establish the efficacy of such an approach and to ascertain further measures that may be implemented to reduce the likelihood of inhibitor development in the high-risk patients.