Platelet transfusions, main therapy of Glanzmann Thromboasthenia (GT), can induce an allo-immunization against human leucocyte antigen and integrin alphaIIbbeta3. We have investigated in our GT patients the rate of allo-immunization and of refractoriness to platelet transfusions. From 1975 until December 2005, we have followed 17 GT patients: 14 type 1, 3 variant type; nine females, eight males; median age at diagnosis 9.8 years (range 1-44.5); median age at the time of the study 35.5 years (range 23.6-68.5). In our patients, 121 bleeding episodes occurred (24 severe, 37 moderate, and 60 mild). Ten major and 22 minor surgical procedures have been performed. Two spontaneous deliveries and three caesarian sections with five live births were performed; moreover, one late foetal loss occurred, and one voluntary abortion was performed. Sixteen of 17 patients have been transfused at least once in life with platelets and/or red blood cells (RBC). All transfused patients have been investigated for the presence of anti-HLA and anti-integrin alphaIIbbeta3 allo-antibodies. The positiveness of allo-antibodies has been demonstrated in 4/16 transfused patients (25%): isolated for anti-HLA in two; isolated for anti-integrin alphaIIbbeta3 in one; and combined in one. In spite of the presence of allo-antibodies, platelet transfusions have always been effective and the haemostasis was not compromised.

Bleeding phenotype in factor XI (FXI)-deficient patients is variable, and not related to baseline FXI:Act. Aims of our study were to describe the characteristics and the management of surgery and deliveries in FXI-deficient patients, and to investigate the relationship between the haemorrhagic phenotype and the baseline FXI:Act. Ninety-five patients were diagnosed and followed in our centre for a median follow-up of 0.9 years (0.1-36.2); median FXI:Act of all patients: 38% (0.5-69%). Fifty-six patients (59%) experienced bleeding episodes not surgery-related. Prior to diagnosis, 64 patients underwent 132 surgeries, and after diagnosis, 23 patients underwent 36 surgeries. Globally 26 of 168 surgeries were prophylactically treated, whereas 142 of 168 were not. As regard as surgeries performed without prophylaxis, 30 bleeding events (21%) occurred in 21 patients. At diagnosis, the median FXI:Act of bleeding and non-bleeding patients was 28% and 37%, respectively, without statistically significant difference between the two groups (P = 0.26). As regard as surgeries performed under prophylactic treatment just 1 bleeding event occurred. Prior to diagnosis, 31 spontaneous deliveries (SD) and eight caesarian sections (CS) were performed without prophylaxis: 4 postpartum haemorrhages (10.5%) occurred (patients FXI:Act: 2%, 6%, 27%, 52.3% respectively). After diagnosis, four SD and five CS were performed with prophylaxis: no postpartum haemorrhages occurred. We confirm the wide bleeding phenotype variability in FXI-deficient patients, not related to the baseline FXI: Act levels. We highlight the importance of performing a correct diagnosis and follow-up, because a good management of prophylactic treatment, dramatically reduces the bleeding rate in case of surgery or deliveries.

Sequential use of the TPO-RAs romiplostim and eltrombopag in ITP patients failing either agent was retrospectively evaluated to assess efficacy and impact of clinical characteristics on outcome. Patients were grouped into 5 categories: efficacy issues: 1 TPO-RA failure; loss of response; non-efficacy issues: platelet fluctuations; patient's preference; adverse event development. Either one TPO-RA sequence was analyzed at 3 month and at last follow-up. 106/546 patients on TPO-RA underwent switch and 65% achieved, regained or maintained a short- term response independent of switch sequence, gender or age; lower response rates were associated with lines of previous therapy; disease duration lowers probability to respond. Clinically, patients switched for efficacy issue did not differ from those switched for non-efficacy issues. Response was achieved/regained in 57.8% of patients switched for efficacy issues, the lowest response rates were observed in non-responders to 1 TPO-RA; 80% of patients switched for non-efficacy issues maintained a response. Platelet fluctuation resolved in 44.4%. Of the 49 patients evaluable for long-term outcome, 27 were in response on therapy; 16 discontinued the TPO-RA for reasons other than efficacy, while only 6 were non responders. We confirm the efficacy of TPO-RA switch; once achieved, response to the 2 TPO-RA seems durable.

The efficacy and safety of thrombopoietin-receptor agonists (TRAs) in elderly patients with primary immune thrombocytopenia (ITP) is uncertain. In 384 ITP patients treated with TRAs when aged ≥60 years, we investigated TRAs response and switch, thrombotic/hemorrhagic risk, and sustained responses off-treatment (SROT). After 3 months, 82.5% and 74.3% of eltrombopag and romiplostim-treated patients achieved a response, respectively (p=0.09); 66.7% maintained the response (median follow-up: 2.7 years). Eighty-five (22.2%) patients switched to the alternative TRA; while no cross-toxicity was observed, 83.3% of resistant patients had a response after the switch. During TRA, 34 major thromboses (3 fatal) and 14 major hemorrhages (none fatal) occurred in 18 and 10 patients, respectively, and were associated with thrombosis history (SHR: 2.04, p=0.05) and platelet count <20x109/L at TRA start (SHR: 1.69, p=0.04), respectively. A recurrent event occurred in 15.6% of patients surviving thrombosis, in all cases but one during persisting TRA treatment (incidence rate: 7.7 per 100 patient-years). All recurrences occurred in the absence of adequate antithrombotic secondary prophylaxis. Sixty-two (16.5%) responding patients discontinued TRA; 53 (13.8%) patients maintained SROT, which was associated with TRA discontinuation in complete response (p<0.001). Very old age (≥75, 41.1%) was associated with more frequent TRAs start in persistent/acute phase but not with response or thrombotic/hemorrhagic risk. TRAs are effective in elderly ITP patients, with no fatal haemorrhages and with SROT in a significant portion of patients; in patients with thrombosis history caution is warranted and a careful risk/benefit balance should be carried out.

Hemophilia B (HB) is an X-linked bleeding disorder caused by deficiency of factor IX (FIX). Patients with the severe form (FIX <1%) account approximately for 30 to 45% of persons with HB and usually suffer from recurrent joint, soft-tissue, and muscle bleeds. The availability of safe plasma-derived and recombinant products has virtually abolished the risk of viral infections and the adoption of prophylactic regimens has attenuated the impact of hemophilic arthropathy. Therefore, the development of an inhibitor against FIX is currently the most serious complication that can still occur in the new generations of HB patients. The development of an inhibitor in HB is a rare event (1.5-3% of all patients) but is associated with a significant morbidity, related not only to the bleeding risk but also to the frequent occurrence of allergic/anaphylactic reactions and nephrotic syndrome. Due to the relative rarity of this event, few data exist about risk factors, pathophysiology, and clinical aspects of inhibitors in HB. The induction of immune tolerance is often unsuccessful and can be otherwise affected by many complications in patients with history of allergy or anaphylaxis. Therefore, alternative therapeutic strategies and new approaches are developing. The aim of this narrative review is to discuss current knowledge about risk factors, pathophysiology, and clinical aspects of this rare but serious complication.