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James B Bussel

Publications and source records attributed to James B Bussel.

10 recordsLinked to original sources
PubMed2026

Anti-HPA-1a fetal-neonatal alloimmune thrombocytopenia: reframing diagnostics, pathophysiology, and management.

Maternal alloantibodies directed to human platelet antigen 1a (HPA-1a) on fetal platelets can induce fetal-neonatal alloimmune thrombocytopenia (FNAIT), which causes intracranial hemorrhage in 10% to 20% of fetuses/newborns. Presentation is usually unexpected and identified by neonatal bleeding. This review synthesizes advances in diagnosis, pathophysiology, and management that reshape understanding of anti-HPA-1a-mediated FNAIT. Genomic and serologic testing, together with cell-free fetal DNA for fetal HPA typing, allow accurate identification of at-risk pregnancies. HPA-1bb women who carry DRB3∗01:01 are at greatest risk of forming clinically significant anti-HPA-1a. Not only anti-HPA-1a levels but also structural features, particularly decreased Fc fucosylation enhancing Fc gamma receptor-mediated effector functions, more accurately determine disease severity. Furthermore, increased Fc galactosylation may contribute by enhancing complement activation. Fab-mediated effects affect platelets, megakaryocytes, trophoblasts, and endothelial cells. Overall, this explains why anti-HPA-1a levels and neonatal platelet counts alone do not reliably predict bleeding, including intracranial hemorrhage. Anti-HPA-1a also induces placental inflammation, increasing risks of fetal growth restriction and long-term neurodevelopmental impairment, for example, autism. Neonatal management involves random donor and matched platelet transfusions, and IV immunoglobulin (IVIG), if needed. Antenatal IVIG, with/without prednisone administered in an affected pregnancy typically increases fetal platelet counts, with management strategies varying internationally. Blocking neonatal Fc receptor has emerged as an alternative approach to both reduce maternal anti-HPAa-1a levels and inhibit its transplacental transfer. Whether antenatal treatment reduces placental inflammation requires further study. These developments support the importance of identifying predictive biomarkers of fetal risk to guide antenatal management and of preventing affected pregnancies ideally by screening all pregnancies followed by prophylaxis.

Humans↗
PubMed2003

Does Helicobater pylori initiate or perpetuate immune thrombocytopenic purpura?

To determine the prevalence of Helicobacter pylori (H pylori) infection in North American patients with immune thrombocytopenic purpura (ITP) and the effect of H pylori eradication on the platelet count, a prospective study was performed. Seventy-four patients aged 10 years and older (mean age of 41 years) with chronic ITP and a platelet count below 60 x 10(9)/L were enrolled. H pylori infection was found in 22% of patients by means of a breath test and could not be predicted by gastrointestinal symptoms. H pylori-positive patients (52.5 years of age) were older than H pylori-negative patients (38.5 years of age; P =.0035). Fifteen of the 16 H pylori-positive patients were treated and the bacteria was eradicated in 14 (93%). After 3 months, a significant response (platelet count > 50 x 10(9)/L and doubling the initial count) was observed in only one patient. After a median follow-up of 11.5 months, none of the 14 patients had responded. Ten H pylori-negative patients treated with the same regimen also did not increase their platelet counts. In conclusion, unlike several previous reports, this study does not implicate H pylori in the pathogenesis of ITP since the prevalence of H pylori infection was low and eradication of H pylori did not positively influence the course of the ITP.

Adult↗
PubMed2003

Long term follow-up after splenectomy performed for immune thrombocytopenic purpura (ITP).

Splenectomy is the only treatment of ITP known to have "curative" effects in a substantial fraction of patients. However, the true long-term outcome is uncertain and controversial because published series have not adjusted for the duration of follow-up. This IRB-approved retrospective study included all patients with ITP who underwent splenectomy between 1988-1993 at three major medical centers and required a minimum postoperative 5-year follow-up. Complete response (CR) was defined as all postsplenectomy platelet counts >150 x 10(9)/L without treatment; partial response (PR) as platelet counts > or =50 x 10(9)/L without treatment; and failure as platelet counts <50 x 10(9)/L or receiving therapy after splenectomy. Seventy-five patients identified with ITP underwent splenectomy from 1988 to 1993. Three patients died prior to 5-year follow-up, and 56 of the 72 patients (78%) were evaluable with follow-up for five years or longer, median 7.5 years. The immediate postoperative complete remission rate was 77%; 57% of patients have remained in prolonged CR. Thirty-seven patients (66%) have not required any therapy after splenectomy. Eight patients had platelet counts >150 x 10(9)/L for 4-8.5 years before relapsing; no clear plateau was attained in the remission curve. There was no operative mortality. Ten patients (18%) reported minor postoperative bleeding episodes. No life-threatening infections, significant heart disease, or pulmonary hypertension developed after splenectomy in the 434 patient-years of follow-up. This study helps to define the long-term results of splenectomy for ITP.

Adolescent↗
PubMed2003

21. Immunohematologic disorders.

Immunohematologic disorders are a broad group of entities in which hematologic diseases, usually cytopenias, are caused by immune reactions. These reactions lead to the development of hemolytic anemia, thrombocytopenia, or neutropenia, either separately or in combination. Common underlying mechanisms include immunodeficiency, systemic autoimmunity, and drug-induced reactions. Transplacental transfer of maternal alloantibodies can lead to fetal and neonatal cytopenias. Other immune reactions include antibodies to clotting factors, which result in both thrombosis and hemorrhage, and hemolytic and nonhemolytic reactions during transfusion of blood products.

Antibodies↗
PubMed2003

Comparison of thrombopoiesis during ITP and HIV-ITP and response to intravenous gammaglobulin treatment.

Immune thrombocytopenic purpura's diagnosis (ITP) is based on low platelet count and exclusion of clinical conditions rather than a specific diagnostic test. We used the reticulated platelet (RP) assay to study ITP and thrombocytopenia associated with HIV infection (HIV-ITP). Data from 96 ITP and 23 HIV-ITP patients showed low platelet counts (PC) with both high or low %RP suggesting that individuals have different degrees of thrombopoiesis. About 20% of ITP and 46% of HIV-ITP patients had %RP in the 'low' or 'normal' ranges. Grouped by platelet count <30x10(9)/L, 24% ITP and 36% HIV-ITP patients had 'low' to 'normal' %RP. The patient population did not show correlation between PC and %RP, but individuals showed an inverse relationship. Within a week of receiving IVIG, 18 ITP and 9 HIV-ITP patients' PC increased, %RP decreased. Patients with %RP measured within 24 h of IVIG treatment had lower %RP than expected, suggesting dilution by an older platelet population. ITP and HIV-ITP patients' responses to i.v. gammaglobulins were similar. Thrombopoietin levels of ITP patients did not correlate with PC, %RP, or RP count. Estimation of thrombopoiesis by RP assay provides useful information for differentiation among thrombocytopenias.

Adult↗
PubMed2003

Intracranial hemorrhage in immune thrombocytopenic purpura: a retrospective analysis.

PURPOSE: To ascertain characteristics of children with immune thrombocytopenic purpura (ITP) and intracranial hemorrhage (ICH). METHODS: The authors identified 75 published cases of ICH in children with ITP by review of the literature from 1954 to 1998. Data pertaining to the ICH was recorded for age, gender, time from diagnosis of ITP (to ICH), platelet count, head trauma or arteriovenous malformation, concomitant medications, associated infections, other bleeding manifestations, prior treatment, and outcome. RESULTS Sixty-two cases represented 6 months to 20 years of age; 65% of patients were female. The median time from the diagnosis of ITP to ICH was 32 days (range 0 days to 8 years). Fifty of 69 ICH cases (72%) occurred within 6 months of diagnosis, but only 7 (10%) occurred within 3 days of diagnosis. The platelet count was less than 10000/microL in 71.4% of the cases. Treatment prior to the ICH was primarily steroids but also included intravenous immune globulin (IVIG), splenectomy, and others (interferon, azathioprine, or vincristine). There was no difference in mortality of patients before (56%) or after (54%) 1980. CONCLUSIONS: A very low platelet count appears permissive but not sufficient for ICH to occur in children with ITP. ICH occurs more commonly in acute ITP but can occur years after diagnosis. A significant number of patients develop an ICH despite having already initiated steroid treatment of ITP.

Adolescent↗
PubMed2002

Genetic analysis of autoantibodies in idiopathic thrombocytopenic purpura reveals evidence of clonal expansion and somatic mutation.

Although idiopathic thrombocytopenic purpura (ITP) is the most common autoimmune hematologic disorder, little is known about the associated autoantibodies on a molecular level. Consequently, diagnostic assays and therapy for ITP lack specificity. To avoid technical limitations imposed by B-cell immortalization methods, we used repertoire cloning (Fab/phage display) to clone platelet autoantibodies and examine the relation between immunoglobulin (Ig) gene usage, clonality, and antigen specificity. Phage display libraries were constructed from splenocytes from 2 patients with chronic ITP, and competitive cell-surface selection was used to isolate several dozen unique IgG platelet-specific autoantibodies. Platelet-reactive Fabs in both patients were associated almost exclusively with rearrangements of a single Ig heavy-chain variable-region gene (V(H)3-30), despite an apparent diversity of antigen specificities. Comparative analysis of platelet-reactive Fab Ig gene rearrangements from each patient suggested that they evolved from a restricted number of B-cell clones through somatic mutation with high replacement-to-silent mutation ratios. Although V(H)3-30-encoded heavy chains were found with light chains encoded by several different Ig genes, molecular repairing experiments showed exquisite restriction on the specific heavy- and light-chain pairings that permitted platelet reactivity. Together, these data suggest that the development of platelet-reactive antibodies associated with ITP is driven by an encounter with diverse platelet antigens through the clonal expansion of B cells using genetically restricted and highly specific combinations of heavy- and light-chain gene products. The extraordinarily high usage of the V(H)3-30 heavy-chain gene in these patients has implications for the pathogenesis, diagnosis, and management of chronic ITP.

Adult↗
PubMed2002

Does treatment with intermittent infusions of intravenous anti-D allow a proportion of adults with recently diagnosed immune thrombocytopenic purpura to avoid splenectomy?

This study explored whether repeated infusions of intravenous anti-D could allow adults with recently diagnosed immune thrombocytopenic purpura (ITP) who had failed an initial steroid course to postpone and ultimately avoid splenectomy. Twenty-eight Rh(+), nonsplenectomized adults with ITP diagnosed within 1 to 11 months and platelet counts 30 x 10(9)/L (30 000/microL) or below were enrolled. Anti-D was infused whenever the platelet count decreased to 30 x 10(9)/L (30 000/microL) or below. "Response" was defined as a platelet increase of more than 20 x 10(9)/L (20 000/microL) to more than 30 x 10(9)/L (30 000/microL) within 7 days of treatment. Patients were a median 3.5 months from ITP diagnosis at enrollment and had received a median of 2 previous therapies, including prednisone in 26 of 28 cases. They were followed for a median 26 months. A total of 93% responded to their initial infusion of anti-D, and 68% repeatedly responded with counts maintained above 30 x 10(9)/L (30 000/microL) using anti-D alone. Currently, 12 (43%) of 28 patients have been off all treatment for more than 6 months without undergoing splenectomy, 6 maintaining counts above 100 x 10(9)/L (100 000/microL). Seven continue on treatment, 8 underwent splenectomy, and 1 was lost to follow-up at 10 months. One patient discontinued anti-D because of toxicity. Patients with platelet counts at least 14 x 10(9)/L (14 000/microL) at enrollment were more likely to discontinue treatment (P <.05). Anti-D was an effective maintenance treatment for two thirds of Rh(+), nonsplenectomized adults with ITP who had failed an initial steroid course. Intermittent infusions of intravenous anti-D allowed more than 40% of these adults to avoid splenectomy and to achieve stable platelet counts off all therapy, even after many months of treatment. Platelet count at study entry was the primary predictor of outcome.

Adolescent↗
PubMed2002

Elevated IgA and IgM anticardiolipin antibodies in acute Kawasaki disease.

There is marked activation of the endothelium and immune system in Kawasaki disease. Anticardiolipin antibodies (aCL) can cause activation of the endothelium. We measured aCL levels in acute Kawasaki disease patients and compared them to other febrile patients to see whether their aCL responses were different. Twenty-one patients with acute Kawasaki disease and 16 patients with an acute febrile illness were recruited. The aCL levels were measured in the sera of febrile patients and in Kawasaki disease patients prior to immunoglobulin therapy. There was no significant difference between the IgG aCL levels (p = 0.87) between the Kawasaki disease and febrile patients. However, the IgM (p = 0.01) and IgA (p = 0.03) aCL were significantly higher in patients with acute Kawasaki disease than in febrile children. Elevation of IgA aCL has been reported in association with other vasculitides and IgA-secreting plasma cells have been demonstrated in the vascular tissue in Kawasaki disease.

Acute Disease↗