Red cell alloimmunization is associated with development of autoantibodies and increased red cell transfusion requirements in myelodysplastic syndrome.

Up to 90% of patients with a myelodysplastic syndrome require red blood cell transfusion; nevertheless, comprehensive data on red cell alloimmunization in such patients are limited. This study evaluates the incidence and clinical impact of red cell alloimmunization in a large cohort of patients with myelodysplastic syndrome registered in the statewide South Australian-MDS registry. The median age of the 817 patients studied was 73 years, and 66% were male. The cumulative incidence of alloimmunization was 11%. Disease-modifying therapy was associated with a lower risk of alloimmunization while alloimmunization was significantly higher in patients with a revised International Prognostic Scoring System classification of Very Low, Low or Intermediate risk compared to those with a High or Very High risk (P=0.03). Alloantibodies were most commonly directed against antigens in the Rh (54%) and Kell (24%) systems. Multiple alloantibodies were present in 49% of alloimmunized patients. Although 73% of alloimmunized patients developed alloantibodies during the period in which they received their first 20 red cell units, the total number of units transfused was significantly higher in alloimmunized patients than in non-alloimmunized patients (90±100 versus 30±52; P<0.0001). In individual patients, red cell transfusion intensity increased significantly following alloimmunization (2.8±1.3 versus 4.1±2.0; P<0.0001). A significantly higher proportion of alloimmunized patients than non-alloimmunized patients had detectable autoantibodies (65% versus 18%; P<0.0001) and the majority of autoantibodies were detected within a short period of alloimmunization. In conclusion, this study characterizes alloimmunization in a large cohort of patients with myelodysplastic syndrome and demonstrates a signficant increase in red cell transfusion requirements following alloimmunization, most probably due to development of additional alloantibodies and autoantibodies, resulting in subclinical/clinical hemolysis. Strategies to mitigate alloimmunization risk are critical for optimizing red cell transfusion support.

A practical guide to laboratory investigations at diagnosis and follow up in Waldenström macroglobulinaemia: recommendations from the Medical and Scientific Advisory Group, Myeloma Australia, the Pathology Sub-committee of the Lymphoma and Related Diseases Registry and the Australasian Association of Clinical Biochemists Monoclonal Gammopathy Working Group.

Waldenström macroglobulinaemia (WM) is an indolent non-Hodgkin lymphoma which usually presents with symptoms related to infiltration of bone marrow or other tissues like lymph nodes, liver or spleen and has certain unusual clinical manifestations, e.g., renal and central nervous system (CNS) involvement. It also has an array of laboratory features including hypersecretion of IgM, cryoglobulinaemia, increased plasma viscosity and identification of mutated MYD88L265P in more than 90% of cases. In this review, we aim to provide a guide to the laboratory investigations recommended for WM at initial diagnosis and at follow-up. A discussion on the nuances of diagnosis and differential diagnoses is followed by bone marrow (BM) assessment, measurement of paraprotein and other ancillary investigations. Recommendations are provided on laboratory work-up at diagnosis, in the asymptomatic follow-up phase, and during and post-treatment. Finally, we briefly discuss the implications of laboratory diagnosis in regard to recruitment and monitoring on clinical trials.