Complete RH and Kell matching related to low alloimmunisation risk in sickle cell disease: prevalence and risk factors of alloimmunisation in a Spanish Tertiary Care National Reference Centre.

BACKGROUND: Red blood cell (RBC) transfusion remains an essential part of sickle cell disease (SCD) management but it can lead to alloimmunisation, with an increased incidence in this population. Prevention is based on RBC antigen phenotype matching, with complete RH and Kell matching being a standard of care. MATERIALS AND METHODS: We performed a retrospective, single-centre study analysing alloimmunisation prevalence and risk factors in a cohort of transfused SCD patients. RESULTS: Eighty-seven patients (96.5% of paediatric age) received 1,781 RBC units (RBCu). Complete RH and Kell matched RBCu represented a median of 100% among total transfusions per patient. Of the 87 patients, 52 (59.8%) underwent chronic transfusion therapy, whereas 35 (40.2%) were only episodically transfused. Seven patients were alloimmunised (8.4%) and eleven antibodies were detected (alloimmunisation rate: 0.62/100 units transfused). 54.6% of these antibodies corresponded to RH-Kell despite the high accomplishment of the RH-Kell matching transfusion protocol. Alloimmunised patients had a median of 90.9% RH-Kell matched transfusions vs 100% in non-alloimmunised patients, but no statistical differences were observed (p=0.127). Number of transfused RBCu (19 vs 7; p=0.023), number of episodic RBCu (8 vs 2; p=0.006), episodic to chronic RBCu ratio (0.57 vs 0.09; p=0.045), number of vaso-occlusive crises (VOC) (4 vs 2; p=0.011), and autoantibody presence (57.1 vs 0%; p<0.001) were all statistically related to alloimmunisation. DISCUSSION: We report a low alloimmunisation prevalence (8.4%) related to a high grade of RH-Kell matching. However, deviation from 100% translates into alloimmunisation, with >50% of alloantibodies corresponding to RH-Kell. Alloimmunisation risk increases with transfusion burden, particularly during acute complications, and in patients with a higher number of VOC, probably reflecting underlying inflammation and disease severity. Further studies will be needed to elucidate additional risk factors and help prevent alloimmunisation in these patients.

Weber-Christian disease with ileocolonic involvement successfully treated with infliximab.

Weber-Christian disease (WCD) is an inflammatory disease whose main histological feature is lobular panniculitis of adipose tissue. The location of panniculitis determines the clinical presentation, being the subcutaneous adipose tissue the most frequent one, followed by liver, spleen, bone marrow and mesenteric adipose tissue. Systemic corticosteroids are first line treatment, but other options should be considered if systemic symptoms are observed or in case of refractory clinical situation. We report herein a case with WCD showing orbital, mesenteric and ileocolonic involvement, which required surgical treatment and also developed postoperative recurrence. Symptoms were resolved by administration of thalidomide and, afterwards, infliximab. To our knowledge, this is the first report of Weber-Christian disease with luminal ileocolonic involvement, treated with infliximab.