Rapid and accurate Bayesian diagnosis of heparin-induced thrombocytopenia.

Prompt diagnostic evaluation of suspected heparin-induced thrombocytopenia (HIT) is critical for guiding initial patient management. We assessed the performance of 3 immunoassays detecting anti-platelet factor 4 (PF4)/heparin antibodies, derived a diagnostic algorithm with a short analytical turnaround time (TAT), and prospectively validated the algorithm. Plasma samples were analyzed by Zymutest-HIA-IgG, HemosIL-AcuStar-HIT-IgG, and ID-H/PF4-PaGIA in retrospective (n = 221) and prospective (n = 305) derivation cohorts. We calculated likelihood ratios of result intervals and cutoff values with 100% negative (NPV) and positive (PPV) predictive values for a positive gold standard functional assay (heparin-induced platelet activation [HIPA]). A diagnostic algorithm was established based on the Bayesian combination of pretest probability and likelihood ratios of first- and second-line immunoassays. Cutoffs with 100% PPV for positive HIPA were >3.0 U/mL (HemosIL-AcuStar-HIT-IgG) and titer ≥16 (ID-H/PF4-PaGIA); cutoffs with 100% NPV were <0.13 U/mL and ≤1, respectively. During the prospective validation of the derived algorithm (n = 687), HemosIL-AcuStar-HIT-IgG was used as unique testing in 566 (82.4%) of 687 cases (analytical TAT, 30 minutes). In 121 (17.6%) of 687 unresolved cases, ID-H/PF4-PaGIA was used as second-line testing (additional TAT, 30 minutes). The algorithm accurately predicted HIT in 51 (7.4%) of 687 patients and excluded it in 604 (87.9%) of 687 patients, leaving only 20 (2.9%) cases unresolved. We also identified 12 (1.7%) of 687 positive predictions not confirmed by HIPA: 10 patients with probable HIT despite negative HIPA and 2 possible false-positive algorithm predictions. The combination of pretest probability with first- and second-line immunoassays for anti-PF4/heparin antibodies is accurate for ruling in or out HIT in ≥95% of cases within 60 minutes. This diagnostic approach improves initial management of patients with suspected HIT.

[The role of splenectomy in fever of unknown origin : a literature review based on a case report]. / Place de la splénectomie dans la fièvre d'origine indéterminée - Revue de la littérature à partir d'un cas.

The management fever of unknown origin (FUO) is a situation often encountered in internal medicine and remains considered a challenge despite advances in the medical field. Defined as a persisting fever despite extensive investigation, cases of FUO often require hospitalization and invasive diagnostic procedures. The role of PET-CT in FUO has been well described in recent years. However, the literature concerning the role of splenectomy in the diagnostic workup is scarce and no standard protocol has been established. Based on a case report, we describe a situation where splenectomy was key in the investigation of a case of FUO, leading to the diagnosis of a high-grade B cell lymphoma. We performed a non-systematic review of the literature to assess the relevance, utility, and risks of splenectomies in the investigation of fever of unknown origin.

La prise en charge d'une fièvre d'origine indéterminée (FOI) est une situation souvent rencontrée en médecine interne. Définie comme une fièvre persistante sans étiologie malgré plusieurs investigations, elle requiert souvent une hospitali sation et des examens parfois invasifs. La place du PET-CT dans la FOI a bien été décrite ces dernières années. Cependant, la littérature concernant l'utilité de la splénectomie dans la recherche étiologique de la FOI est peu abondante. À partir d'un cas clinique, nous décrivons une situation dans laquelle la splénectomie a été l'élément clé dans l'investigation d'une FOI menant au diagnostic de lymphome à cellules B. Nous avons réalisé une revue non systématique de la littérature pour évaluer la pertinence, l'utilité et les risques de la splénectomie dans l'investigation d'une FOI.

Successful treatment with rituximab and mycophenolate mofetil of refractory autoimmune hemolytic anemia post-hematopoietic stem cell transplant for dyskeratosis congenita due to TINF2 mutation.

AIHA following allogeneic HSCT is appearing more frequently in the literature. It occurs as a result of donor cell-derived antibodies targeting donor red cell antigens. Little guidance exists on the management of such patients, particularly in the pediatric setting. First-line conventional treatment is corticosteroids and/or immunoglobulin therapy with monoclonal antibody therapy reserved for treatment failure. We report our experience of a child refractory to immunoglobulin and steroid therapy who required several infusions of rituximab and immunomodulatory therapy to obtain a clinically significant response.

A multi-centre retrospective study of rituximab use in the treatment of relapsed or resistant warm autoimmune haemolytic anaemia.

This retrospective analysis assessed the response, safety and duration of response to standard dose rituximab 375 mg/m(2) weekly for four weeks as therapy for patients with primary or secondary warm autoimmune haemolytic anaemia (WAIHA), who had failed initial treatment. Thirty-four patients received rituximab for WAIHA in seven centres in the Republic of Ireland. The overall response rate was 70·6% (24/34) with 26·5% (9/34) achieving a complete response (CR). The time to response was 1 month post-initiation of rituximab in 87·5% (21/24) and 3 months in 12·5% (3/24) of patients. The median duration of follow-up was 36 months (range 6-90 months). Of the patients who responded, 50% (12/24) relapsed during follow up with a median time to next treatment of 16·5 months (range 6-60 months). Three patients were re-treated with rituximab 375 mg/m2 weekly for four weeks at relapse and responded. There was a single episode of neutropenic sepsis. Rituximab is an effective and safe treatment for WAIHA but a significant number of patients will relapse in the first two years post treatment. Re-treatment was effective in a small number of patients, suggesting that intermittent pulse treatment or maintenance treatment may improve long-term response.

A novel base change leading to Hb Vanderbilt [ß89(F5)Ser→Arg, AGT>AGA].

We describe a high oxygen affinity hemoglobin (Hb) variant (Hb Vanderbilt) as a result of a heterozygous novel base change from T to A at codon 89 (AGT>AGA) leading to an amino acid change from serine to arginine.

Fibrin clot properties to assess the bleeding phenotype in unrelated patients with hypodysfibrinogenemia due to novel fibrinogen mutations.

Congenital hypodysfibrinogenemia is a rare fibrinogen disorder, defined by decreased levels of a dysfunctional fibrinogen. We present the functional and structural characterization of two new fibrinogen variants. A duplication of 32 bases in FGA exon 5, p.Ser382GlyfsTer50 was identified in a patient (P1) with history of hemoptysis and traumatic cerebral bleeding. A missense mutation in FGG exon 8, p.Ala353Ser was identified in two siblings (P2 and P3) with tendency to bruising and menorrhagia. Fibrin polymerization was studied in plasma and in purified fibrinogen by turbidimetry. Fibrin structure was studied by a permeability assay, laser scanning confocal microscopy (LSCM) and scanning electron microscopy (SEM). In both plasma and purified fibrinogen samples, all patients had an abnormal polymerization characterized by a decreased maximal absorption compared to controls. The permeation constant (Ks) was markedly increased in all patients: 31 ± 9 × 10-9 cm2 in P1, and 20 ± 0.1 × 10-9 cm2 in P2 and P3, compared to 6 ± 2 × 10-9 cm2 in the control (p < 0.05). The presence of very large pores that accounts for the increased Ks was confirmed by LSCM and SEM patients' clots images. By SEM, the patients' fibrin fibers diameters were thicker: 90 ± 25 nm in P1, 162 ± 64 nm in P2 and 132 ± 46 nm in P3 compared to 74 ± 25 nm in control (p < 0.0001). In conclusion, both new causative fibrinogen mutations altered clot structure by forming thick fibers, diminishing fiber branching, and increasing pore filling space. These structural changes to clots explain the patients' bleeding phenotypes.

Mutational Epidemiology of Congenital Fibrinogen Disorders.

BACKGROUND: Numerous mutations in FGA, FGB or FGG lead to congenital fibrinogen disorders (CFDs), but their epidemiology is not well characterized. The aim of this study was to evaluate the molecular epidemiology of CFD and to develop a genotyping strategy. METHODS: Genetic data from 266 unrelated CFD patients genotyped at our laboratory and from a CFD open access database (n = 1,142) were evaluated. We developed a step-wise screening strategy for the molecular diagnosis of CFD and prospectively tested this strategy on 32 consecutive CFD probands. RESULTS: We identified 345 mutated alleles overall, among 187 heterozygous, 63 homozygous and 16 compound heterozygous individuals. Afibrinogenemia was almost always caused by null mutations (98.6%), mainly in FGA (85%). Hypofibrinogenemia was mainly caused by missense mutations of FGB or FGG (54.2%). Dysfibrinogenemia was almost always caused by heterozygous missense mutations (99.3%) in FGA and FGG. Hotspot mutations were prevalent among quantitative (33.1%) and qualitative fibrinogen disorders (71.1%). The mutational cluster at our laboratory was similar with that reported in the CFD open access database. The proposed step-wise genetic screening strategy proved efficient in both the development and validation samples for CFD: the screening of FGA exons 2, 4, 5 and FGG exon 8 and search for the 11 kb deletion of FGA led to the identification of approximately 80% of mutated alleles, including 15 new mutations. CONCLUSION: The described molecular epidemiology of CFD is complex. The proposed step-wise genetic screening strategy may provide an efficient way to identify causative mutations analysing a minimal number of exons.

Safety of trastuzumab (Herceptin) during pregnancy: two case reports.

We report on two cases of women on trastuzumab therapy for breast cancer who became pregnant and delivered healthy live infants. At the time of reporting the children are growing and developing normally (ages 3 and 2).