ELP protocol: an original approach for the mitigation of anti-CD38 interference.

BACKGROUND: Transfusion medicine is facing new challenges from therapies which interfere with pre-transfusional tests, such as monoclonal antibodies targeting blood-cell antigens. Anti-CD38 monoclonal antibodies, widely used to treat multiple myeloma, cause panreactivity of indirect antiglobulin test; this can be resolved by treating cells with dithiothreitol to disrupt the CD38 disulphide bonds expressed on red blood cell surfaces. Interference mitigation strategy with dithiothreitol, however, has some drawbacks: it entails losing the traceability of results and the denaturation of blood group systems sensitive to reducing agents; it takes time to perform and quality controls are lost. MATERIALS AND METHODS: Panels were treated with 0.2 mol/L dithiothreitol and stored for 30 days with a commercial preservative solution. On day 30, we measured the hemolysis indices and ability to eliminate daratumumab and isatuximab interference in the treated cells using indirect antiglobulin test. We also tested the stability of erythrocyte antigenic structure by screening 42 samples with known antibodies; tests were repeated on day 1, 7, 15 and 30. All indirect antiglobulin testing was performed on gel card. RESULTS: After 30 days from treatment, panels preserved in preservative solution showed hemolysis indices comparable to untreated panels: all cases of interference by anti-CD38 in pre-transfusional tests were successfully mitigated. All antibodies were detected after 30 days, except for KEL system antibodies, as expected, although there was a detectability of anti-Kell antibodies in high titer samples (the first detection in dithiothreitol-treated cells since 1983). DISCUSSION: We propose the Extended Lifetime Protocol; a simple card-based method which is cheap and traceable, that combines the strengths of anti-CD38 mitigation strategies. It makes it possible to treat and store, at the same time, a sufficient volume of red blood cells, that can be used for the following 30 days, to avoid any delay in transfusional requests.

Evans syndrome secondary to chronic lymphocytic leukaemia: presentation, treatment, and outcome.

Evans syndrome (ES) is defined by the combination (either simultaneous or sequential) of immune thrombocytopenia (ITP) and autoimmune haemolytic anaemia (AIHA). When related to secondary conditions, ES may arise in patients with chronic lymphocytic leukaemia (CLL), which is frequently associated to autoimmune cytopenias (AIC). We analysed 25 patients with ES secondary to CLL, which were identified from a large series of consecutive patients with CLL, diagnosed and followed up in two institutions. They represented 2.9 % of the whole series. Thirteen patients presented with concurrent ITP and AIHA (simultaneous ES), while others developed the two AIC sequentially. Occurrence of ES was associated with unfavourable biological prognostic factors like ZAP-70 expression, unmutated immunoglobulin heavy chain variable region gene status, 17-p13 deletion and TP53 gene mutations. Of note, the majority of patients with ES (66 %) had stereotyped B cell receptor configuration. Most patients had short-lasting remissions and required second-line treatments to control the autoimmune manifestations of ES. Patients with ES were associated with inferior survival compared to patients not developing AIC, especially when ES developed early in the course of CLL, although the reduced survival was not confirmed by multivariate analysis. In conclusion, ES secondary to CLL is a difficult-to-treat complication, characterised by adverse biological features and clinical outcome.