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Biomedical subjects

Etienne Vilmer

Publications and source records attributed to Etienne Vilmer.

At least 19 recordsLinked to original sources
PubMed2006

The prognostic significance of CDKN2A, CDKN2B and MTAP inactivation in B-lineage acute lymphoblastic leukemia of childhood. Results of the EORTC studies 58881 and 58951.

BACKGROUND AND OBJECTIVES: Deletion and methylation of the 9p21 chromosomal region are frequent in childhood acute lymphoblastic leukemia (ALL) but the prognostic significance is controversial. They inactivate CDKN2A, a gene encoding both p16INKa and p14ARF and, in some cases, contiguous genes that may influence chemosensitivity, such as CDKN2B encoding p15INKb or MTAP encoding methylthioadenosine phosphorylase. DESIGN AND METHODS: CDKN2A inactivation by deletion or methylation was studied using gene dosage and methyl-specific polymerase chain reaction. RESULTS: Bi-allelic and mono-allelic inactivation were found in, respectively, 38 (17%) and 31 (14%) of 227 children with B-lineage ALL enrolled in EORTC trials. Although CDKN2A inactivation was more often associated with poor prognostic features in B-lineage ALL, it failed to influence the outcome of the patients significantly. Bi-allelic CDKN2B and MTAP co-inactivation were found in 36 (16%) and 24 (11%) of patients, respectively, and did not influence the 6-year event-free survival rate either, even when the analysis was restricted to CDKN2A inactivated ALL. INTERPRETATION AND CONCLUSIONS: In this study of 227 cases of childhood B-lineage ALL, inactivation of CDKN2A, CDKN2B and MTAP did not influences the patients' outcome.

Adolescent↗
PubMed2005

Efficacy and safety of rituximab in B-cell post-transplantation lymphoproliferative disorders: results of a prospective multicenter phase 2 study.

B-cell posttransplantation lymphoproliferative disorder (B-PTLD) is a rare but severe complication of transplantation, with no consensus on best treatment practice. This prospective trial, the first to test a treatment for PTLD, was designed to evaluate the efficacy and safety of rituximab in patients with B-PTLD after solid organ transplantation (SOT). Forty-six patients were included and 43 patients were analyzed. Patients were eligible if they had untreated B-PTLD that was not responding to tapering of immunosuppression. Treatment consisted of 4 weekly injections of rituximab at 375 mg/m2. At day (d) 80, 37 (86%) patients were alive, and the response rate was 44.2%, including 12 complete response/unconfirmed complete response (CR/CRu). The only factor predictive of a response at d80 was a normal lactate dehydrogenase level (P = .007, odds ratio [OR] = 6.9). At d360, responses were maintained in 68% of patients, and 56% of patients were alive. The overall survival rate at 1 year was 67%. We conclude that rituximab is effective and safe in PTLD, with stable responses at 1 year. The response rate and overall survival might be improved by combining rituximab with other treatments.

Adolescent↗
PubMed2005

Improvement in bone mineral density and body composition in survivors of childhood acute lymphoblastic leukemia: a 1-year prospective study.

OBJECTIVES: Abnormalities in bone mineral density (BMD), body composition, and bone metabolism have been reported in children who were treated for acute lymphoblastic leukemia (ALL) during and after completion of therapy. However, these studies are cross-sectional, and no longitudinal data are available in a large group of patients after completion of therapy. In the present study, 1-year longitudinal changes in BMD, body composition, and bone metabolism were evaluated in children with ALL during the first 3 years after completion of therapy without cranial irradiation. METHODS: BMD of total body (TB; g/cm(2)), areal and apparent volumetric lumbar spine (L2-L4), lean body mass, and percentage of body fat were measured by dual-energy x-ray absorptiometry in 37 children (median age: 7.9 years; range: 4.7-20.6 years) who were treated for ALL at a median age of 3.3 years (range: 1.1-16.6 years), after a median time of 2.2 years after the completion of treatment, and after a 1-year follow-up period. Two control subjects (n = 74) who were matched for gender, age, and pubertal stage were also longitudinally investigated for body composition for 1 year. Usual serum biochemical markers of calcium metabolism and bone turnover were measured in patients during the study period. RESULTS: A slight decrease in TB BMD was found after a median time of 2.2 years after the completion of therapy for ALL in childhood. Patients showed a significantly lower median TB BMD when evaluated <1.5 years as compared with those at >or=1.5 years since completion of therapy. At the time of first evaluation, the percentage of body fat mass was significantly higher and patients were physically less active than their matched control subjects. Although, as expected, during the 1 year of follow-up both groups showed an annual increment in their BMD measurements, a significantly higher increase in TB BMD was observed in patients in comparison with control subjects. During this same period, the increase in the percentage of body fat mass was slightly lower in ALL patients as compared with control subjects. At the end of the follow-up year, BMD, body-composition parameters, and physical activity of ALL patients were similar to those observed in matched control subjects. Serum biochemical markers of bone turnover were normal at both evaluations. CONCLUSIONS: A significant increase in TB BMD and a tendency to a lesser increase in percentage of body fat mass were observed during the study period in ALL patients as compared with chronological age-, gender-, and pubertal stage-matched control subjects. These findings suggest a positive effect of long-term completion therapy and increase in physical activity on BMD, body composition, and bone metabolism in patients who have been treated for ALL.

Absorptiometry, Photon↗
PubMed2005

Post-transplant lymphoproliferative disorder in children: incidence, prognosis, and treatment options.

Post-transplant lymphoproliferative disorder (PTLD) after solid organ or hematopoietic stem cell transplantation in children is a serious complication that has been responsible for high mortality rates over recent years. PTLDs are part of a clinically and histologically heterogeneous group of B-lymphocyte proliferations mostly induced by Epstein-Barr virus (EBV) in a context of immunosuppression. Major risk factors for PTLDs in solid organ transplantation are the EBV serostatus mismatch and the intensity, duration, and type of immunosuppression. T-cell depletion and the HLA-mismatched donor and recipient are the main risk factors following hematopoietic stem cell transplantation. For a long time, the only safe and effective therapeutic approach to PTLD was reduction of immunosuppression, with a risk of graft rejection. Based on a better knowledge of the pathophysiology and risk factors for PTLD, preventive and pre-emptive strategies have been recently proposed to control PTLD. New treatment modalities, such as anti-B-cell antibodies, cytokine inhibitor therapy, or anti-EBV cytotoxic T lymphocytes are promising and may improve the outcome of PTLD. These therapeutic approaches need to be further evaluated, especially in the context of pre-emptive strategies adapted to predictive markers of EBV-induced PTLD.

Anti-Bacterial Agents↗
PubMed2005

Analysis of risk factors for myelodysplasias, leukemias and death from infection among patients with congenital neutropenia. Experience of the French Severe Chronic Neutropenia Study Group.

BACKGROUND AND OBJECTIVES: The two main complications of severe chronic neutropenia are fatal sepsis and myelodysplasia/acute leukemia (MDS/AL). Granulocyte colony-stimulating factor (G-CSF) therapy has significantly reduced the frequency and severity of infections, but its possible influence on the risk of malignancy is not known. DESIGN AND METHODS: The French Severe Chronic Neutropenia (SCN) Registry has prospectively collected data since 1994 on 231 patients with various forms of SCN, namely severe congenital neutropenia (n=101), cyclic neutropenia (n=60), glycogen storage disease type Ib (GSDIb) (n=15) and Shwachman-Diamond syndrome (SDS)(n=55). The median overall follow-up is 11.1 years. Parameters of exposure to G-CSF therapy, such as the time averaged dose, follow up after first use of G-CSF, and the cumulative dose, have been recorded. RESULTS: Eight septic deaths occurred, of which 6 among patients with severe congenital neutropenia and 2 in patients with cyclic neutropenia; none of these 8 patients was receiving G-CSF therapy. No septic deaths occurred during G-CSF therapy. Thirteen cases of MDS/AL were recorded. The cumulative incidence of MDS/AL was 2.7% (SD 1.3%) at 10 years and 8.1% (SD 2.7%) at 20 years. INTERPRETATION AND CONCLUSIONS: Risk factors for MDS/AL were the diagnostic category, the severity of neutropenia, younger age at diagnosis, and strong exposure to G-CSF. MDS/AL only occurred in patients with severe congenital neutropenia and SDS. Owing to their particular susceptibility to infections, patients with severe congenital neutropenia had the strongest exposure to G-CSF; the risk of leukemia increased with the degree of G-CSF exposure in this subgroup.

Acute Disease↗
PubMed2004

Autoimmune lymphoproliferative syndrome with somatic Fas mutations.

BACKGROUND: Impaired Fas-induced apoptosis of lymphocytes in vitro is a principal feature of the autoimmune lymphoproliferative syndrome (ALPS). We studied six children with ALPS whose lymphocytes had normal sensitivity to Fas-induced apoptosis in vitro. METHODS: Susceptibility to Fas-mediated apoptosis and the Fas gene were analyzed in purified subgroups of T cells and other mononuclear cells from six patients with ALPS type III. RESULTS: Heterozygous dominant Fas mutations were detected in the polyclonal double-negative T cells from all six patients. In two patients, these mutations were found in a fraction of CD4+ and CD8+ T cells, monocytes, and CD34+ hematopoietic precursors, but not in hair or mucosal epithelial cells. CONCLUSIONS: Somatic heterozygous mutations of Fas can cause a sporadic form of ALPS by allowing lymphoid precursors to resist the normal process of cell death.

Adolescent↗
PubMed2003

Munc13-4 is essential for cytolytic granules fusion and is mutated in a form of familial hemophagocytic lymphohistiocytosis (FHL3).

Secretion of cytolytic granules content at the immunological synapse is a highly regulated process essential for lymphocyte cytotoxicity. This process requires the rapid transfer of perforin containing lytic granules to the target cell interface, followed by their docking and fusion with the plasma membrane. Defective cytotoxicity characterizes a genetically heterogeneous condition named familial hemophagocytic lymphohistiocytosis (FHL), which can be associated with perforin deficiency. The locus of a perforin (+) FHL subtype (FHL3), observed in 10 patients, was mapped to 17q25. This region contains hMunc13-4, a member of the Munc13 family of proteins involved in vesicle priming function. HMunc13-4 mutations were shown to cause FHL3. HMunc13-4 deficiency results in defective cytolytic granule exocytosis, despite polarization of the secretory granules and docking with the plasma membrane. Expressed tagged hMunc13-4 localizes with cytotoxic granules at the immunological synapse. HMunc13-4 is therefore essential for the priming step of cytolytic granules secretion preceding vesicle membrane fusion.

Amino Acid Sequence↗
PubMed2003

Clinical significance of HOX11L2 expression linked to t(5;14)(q35;q32), of HOX11 expression, and of SIL-TAL fusion in childhood T-cell malignancies: results of EORTC studies 58881 and 58951.

In a series of 153 children with T-cell malignancies enrolled in 2 consecutive European Organization for Research and Treatment of Cancer (EORTC) trials, we assessed the HOX11L2 expression and/or the presence of a t(5;14)(q35;q32). Additionally, in 138 of these patients, HOX11 expression and SIL-TAL rearrangement were also assessed. These alterations were mutually exclusive, and their frequency was 23% (n = 35), 7% (n = 10), and 12% (n = 17), respectively. HOX11L2/t(5;14) positivity was more frequent in acute lymphoblastic leukemia (ALL) with cortical T immunophenotype and in children aged between 6 and 9 years. In contrast with previously reported data, patients positive and negative for HOX11L2/t(5;14) were comparable with regard to clinical outcome as well as to the response to a 7-day prephase treatment or to residual disease at completion of induction therapy. The 3-year event-free survival (EFS) rate (+/- SE percentage) for patients positive and negative for HOX11L2/t(5;14) was 75.5% (+/- 8.1%) and 68.3% (+/- 5.0%), respectively; the hazard ratio was 0.84 (95% confidence interval, 0.40-1.80). Patients with HOX11-high expression and those with SIL-TAL fusion had low levels of residual disease at the end of induction and a favorable prognosis: the 3-year EFS rate was 83.3% (+/- 8.5%) and 75.3% (+/- 12.6%), respectively. The results obtained in HOX11L2/t(5;14) patients in this study do not confirm the unfavorable prognosis reported in previous studies.

Adolescent↗
PubMed2003

CDKN2A, CDKN2B, and MTAP gene dosage permits precise characterization of mono- and bi-allelic 9p21 deletions in childhood acute lymphoblastic leukemia.

Deletion of the 9p21 chromosomal region is frequently found in childhood acute lymphoblastic leukemia (ALL). The target of these deletions is CDKN2A, a gene encoding both p16(INK4a) and p14(ARF). However, contiguous genes such as CDKN2B, encoding p15(INK4b), or MTAP, encoding methylthioadenosine phosphorylase, can be included in the deletions. Gene dosage by use of real-time PCR has recently been proposed as a promising technical option for the diagnosis of deletions. However, its reliability and its capacity to detect mono-allelic deletions in tumor samples are controversial. To evaluate the frequency and extent of deletions in 284 children with ALL, we devised a real-time PCR assay for CDKN2A, CDKN2B exons 1beta and 3, and MTAP gene dosage and validated it by comparison with loss-of-heterozygosity analysis. We show that, if several controls and adjustments are performed, real-time PCR can provide a reliable test for mono- and bi-allelic deletions in ALL. We propose a strategy that overcomes the major caveats of such a dosage in tumor samples: aneuploidy and contamination by normal cells. By use of this assay, we found bi-allelic deletions in 58 and 17% of T- and B-lineage ALL, respectively. Mono-allelic deletion was observed in about 15% of cases, stressing the importance of their detection in ALL. CDKN2B and/or MTAP co-deletions were highly variable in both T- and B-lineage ALL, making ALL with 9p21 a rather heterogeneous group. Because proteins encoded by these genes might influence the response to treatment, the prognosis of 9p21-deleted ALL could vary according to the extent of the deletion.

Adolescent↗
PubMed2003

Family history of autoimmune thyroid disease and childhood acute leukemia.

The association between a familial history of autoimmune disease and childhood acute leukemia was investigated in a French case-control study that, overall, was designed to assess the role of perinatal, infectious, environmental, and genetic factors in the etiology of childhood acute leukemia. Familial histories of autoimmune disease in first- and second-degree relatives were compared in 279 incident cases, 240 cases of acute lymphocytic leukemia (ALL) and 39 cases of acute non-lymphoblastic leukemia (ANLL), and 285 controls. Recruitment was frequency matched by age, gender, hospital, and ethnic origin. Odds ratios (OR) were estimated using an unconditional regression model taking into account the stratification variables, socioeconomic status, and familial structure. A statistically significant association between a history of autoimmune disease in first- or second-degree relatives and ALL (OR, 1.7; 95% confidence interval (CI), 1.0-2.8) was found. A relationship between thyroid diseases overall and ALL (OR, 2.0; 95% CI, 1.0-3.9) was observed. This association was more pronounced for potentially autoimmune thyroid diseases (Grave's disease and/or hyperthyroidism and Hashimoto's disease and/or hypothyroidism) (OR, 3.5; 95% CI, 1.1-10.7 and OR, 5.6; 95% CI, 1.0-31.1, respectively for ALL and ANLL), whereas it was not statistically significant for the other thyroid diseases (thyroid goiter, thyroid nodule, and unspecified thyroid disorders) (OR, 1.6; 95% CI, 0.7-3.5 and OR, 1.3; 95% CI, 0.2-7.0, respectively, for ALL and ANLL). The results suggest that a familial history of autoimmune thyroid disease may be associated with childhood acute leukemia.

Adolescent↗
PubMed2002

Immune reconstitution without graft-versus-host disease after haemopoietic stem-cell transplantation: a phase 1/2 study.

BACKGROUND: Allogeneic haemopoietic stem-cell transplantation (HSCT) is the treatment of choice for many haematological malignancies and inherited disorders. When stem cells for transplantation come from a human leucocyte antigen matched unrelated donor, or from a partly mismatched related donor, ex-vivo T-cell depletion of the graft can prevent development of graft-versus-host disease, but lead in turn to a delay in immune reconstitution and a concordant increase in incidence of opportunistic infections and leukaemic relapses. We aimed to infuse T cells selectively depleted in allogeneic T cells that cause graft-versus-host disease using an ex-vivo procedure designed to eliminate alloactivated donor T cells, with an immunotoxin that reacts with a cell surface activation antigen, CD25. METHODS: We did a phase 1/2 study, in which 1-8 x 10(5) allodepleted T cells/kg were infused between days 15 and 47 into 15 paediatric patients who had acquired or congenital haemopoietic disorders and who received HSCT on day 0. Occurrence of graft-versus-host disease and time to immune reconstitution were assessed. No treatment for graft-versus-host disease was given. FINDINGS: Less than 1% residual anti-host alloreactivity was recorded in 12 of 16 procedures. Other immune responses were preserved by the allodepletion procedure in 12 cases. No cases of severe (greater than grade II) graft-versus-host disease arose. Evidence for early T-cell expansion was shown in three patients with continuing viral infections. Specific antiviral responses, such as strong cytolytic activity, were noted. INTERPRETATION: Our results show that ex-vivo selective depletion of T cells that cause graft-versus-host disease is efficient and feasible, even in haploidentical settings.

Case-Control Studies↗
PubMed2002

Outcome of treatment in childhood acute lymphoblastic leukaemia with rearrangements of the 11q23 chromosomal region.

BACKGROUND: The prognosis and optimum treatment of childhood acute lymphoblastic leukaemia (ALL) with abnormalities of chromosomal band 11q23 are controversial. We aimed to identify prognostic factors that might help in planning future therapy, and to assess the effectiveness of haemopoietic stem-cell transplantation in patients with the t(4;11) translocation, which is associated with a particularly poor outcome. METHODS: We reviewed data on 497 children and young adults who had ALL with various 11q23 abnormalities, including the translocations t(4;11), t(9;11), and t(11;19). All patients were treated with intensive chemotherapy, with or without haemopoietic stem-cell transplantation in first complete remission, by 11 study groups and single institutions from 1983 to 1995. FINDINGS: Age was the most important prognostic factor. In a Cox's proportional-hazard model stratified by 11q23 abnormalities, infants younger than 1 year fared significantly worse than patients 1 year of age or older (hazard ratio for event-free survival 1 84 [95% CI 1 38-2 47], p=0 0001). Among infants, any category of 11q23 abnormality conferred a dismal outcome, whereas in older patients, t(4;11) and t(9;11) were associated with a worse outcome than were other 11q23 changes. In the largest subgroup--256 patients with t(4;11)--any type of transplantation was associated with significantly worse disease-free survival (1 61 [1 10-2 35], p=0 014) and overall survival (1 76 [1 08-2 45], p=0 004) compared with chemotherapy only. Even transplantation with stem cells from HLA-matched related or HLA-matched unrelated donors tended to be associated with a worse outcome than chemotherapy alone. INTERPRETATION: The prognosis of acute lymphoblastic leukaemia with an 11q23 abnormality is particularly dismal in infants. Allogeneic transplantation with haemopoietic stem cells from an HLA-matched related donor does not seem to improve the clinical outcome in patients with t(4;11)-positive leukaemia.

Age Distribution↗
PubMed2002

Comparison of Escherichia coli-asparaginase with Erwinia-asparaginase in the treatment of childhood lymphoid malignancies: results of a randomized European Organisation for Research and Treatment of Cancer-Children's Leukemia Group phase 3 trial.

Asparaginase is an enzyme used in the treatment of acute lymphoblastic leukemia and lymphoblastic lymphoma in children. It has minimal bone marrow toxicity. Its major side effects are anaphylaxis, pancreatitis, diabetes, coagulation abnormalities, and thrombosis, especially intracranial. It is derived from 2 different sources: Escherichia coli and Erwinia chrysanthemi. Nonrandomized clinical studies have suggested a similar efficacy of these 2 types of asparaginases and a lower toxicity for Erwinia-asparaginase. The European Organisation for Research and Treatment of Cancer-Children's Leukemia Group (EORTC-CLG) 58881 trial randomized 700 children with acute lymphoblastic leukemia or lymphoblastic lymphoma to either E coli- or Erwinia-asparaginase at the same dosage of 10 000 IU/m(2) twice weekly to compare toxicity and efficacy. Coagulation abnormalities were more frequent in the E coli-asparaginase than in the Erwinia-asparaginase arm of the study (30.2% versus 11.9%, P <.0001). The incidence of other toxicity was not significantly different. In the Erwinia-asparaginase arm, more patients failed to achieve complete remission (4.9% versus 2.0%; P =.038) and the relapse rate was higher, leading to shorter event-free survival (hazard ratio,1.59; 95% CI, 1.23-2.06; P =.0004). The estimate of event-free survival rate (SE) at 6 years was 59.8% (2.6%) versus 73.4% (2.4%). Overall survival rate at 6 years was also lower in the Erwinia-asparaginase arm at 75.1% (2.3%) versus 83.9% (2.0%), P =.002. With the dose scheduling used in this protocol, E coli-asparaginase induced more coagulation abnormalities but was superior to Erwinia-asparaginase for the treatment of childhood lymphoid malignancies.

Adolescent↗
PubMed2002

Hydroxyurea corrects the dysregulated L-selectin expression and increased H(2)O(2) production of polymorphonuclear neutrophils from patients with sickle cell anemia.

Impaired polymorphonuclear neutrophil (PMN) functions during sickle cell anemia (SCA) may have a pathogenic role in the onset of vasoocclusive events. We used flow cytometry to study, in whole blood, the adhesion molecule expression and respiratory burst of PMNs from children with SCA. Three different clinical groups were studied: (1) patients with no history of vasoocclusive events (n = 15); (2) patients with a history of vasoocclusive events (n = 17); and (3) patients receiving hydroxyurea therapy for severe vasoocclusive events (n = 9). Unstimulated PMNs showed decreased L selectin expression and increased H(2)O(2) production whatever the severity of the disease, reflecting PMN activation. This could contribute to endothelial activation reflected by abnormal plasma levels of soluble adhesion molecules (soluble intercellular adhesion molecule-1, sE selectin, and sL selectin). After stimulation with bacterial N-formyl peptides (N-formyl-methionyl-leucyl-phenylalanine [fMLP]), PMNs from untreated patients with a history of vasoocclusive events showed dysregulated L selectin shedding and increased H(2)O(2) production. Furthermore, in these patients, tumor necrosis factor priming followed by fMLP stimulation induced an H(2)O(2) production significantly higher than in the other patient groups and controls. These impairments could immobilize PMNs on the endothelium, thereby inducing reduced blood flow and fostering microvascular occlusion and vascular damage. In contrast, children treated with hydroxyurea showed near-normal basal and poststimulation H(2)O(2) production as well as normal L selectin shedding after stimulation but no change in plasma levels of soluble adhesion molecules. To our knowledge, this is the first report showing major qualitative changes of PMN abnormalities upon hydroxyurea treatment in SCA patients. This strongly suggests that PMNs are a primary target of this drug.

Adolescent↗
PubMed2002

Molecular analysis of nonrandom 8q12 deletions in acute lymphoblastic leukemia: identification of two candidate genes.

Acute lymphoblastic leukemia is the most common malignancy in childhood. High-resolution allelotyping performed in our laboratory showed new chromosomal sites of nonrandom deletions. We have focused our work on 8q12 deletions, which we have found in about 4% of patients (eight of 205 informative cases). These deletions were of small size (less than 1 Mb) in all but one patient, and the deleted region common to all patients was delineated between two microsatellite markers (D8S1113 and D8S1763). This region was sequenced entirely from two overlapping bacterial artificial chromosomes. The common deleted region (120 kb) had a low GC content (37%), was composed more than 50% of LINE sequences, and contained only two candidate genes. The centromeric deletion borders were clustered within an interval of 33 kb between two microsatellite markers. This interval contains the first exon of an HMG-1-related gene (KIAA0808) and a putative gene, DL8q12, predicted to encode a protein with 231 amino acid residues with no homolog in protein databases. Analysis of the available mRNA from lymphoblastic cells of two patients with 8q12 deletions using common polymorphisms in the 3' UTR of KIAA0808 showed monoallelic expression of this gene. Identification of a biallelic polymorphism in the first exon of DL8q12 showed that this gene was deleted in two of four informative cases. Sequencing of the exons of both genes from all patients with 8q12 deletions did not show any mutation, which suggests that neither of these genes behaves as a classic tumor suppressor gene.

Adolescent↗
PubMed2002

Severe autoimmune hemolytic anemia caused by a warm IgA autoantibody directed against the third loop of band 3 (RBC anion-exchange protein 1).

BACKGROUND: Autoimmune hemolytic anemia associated with only IgA autoantibodies reacting optimally at 37 degrees C (WAIHA) is exceedingly rare. When identified, warm IgA autoantibodies specificities are usually directed to antigens of the Rh system. However, like IgG autoantibodies, the specificity of the majority of these antibodies is not identified. CASE REPORT: A case of a 3-year-old boy in whom a life-threatening IgA WAIHA occurred suddenly is reported. Following initial RBC transfusions and treatment with steroids at a dose of 3 mg per kg, which was slowly tapered, stabilization to a state of compensated hemolysis was achieved, persisting 4 months before complete resolution. There was no recurrence within a 16-month follow-up. STUDY DESIGN AND METHODS: The standard DAT in a gel column method with anti-IgG and anticomplement reagents was negative. However, the same method with an anti-IgA was strongly positive. RESULTS: The serum and the eluate obtained after acid elution reacted with all normal RBCs tested. Enzymatic treatment of panel RBCs by alpha-chymotrypsin and pronase abolished the reactivity. The reaction was completely inhibited by RBC incubation with four different MoAbs directed against the third extracellular loop of band 3, the RBC anion-exchange protein 1 (AE1), whereas MoAbs against other specificities showed no effect. CONCLUSIONS: This is the first report of an IgA autoantibody directed against the band 3 (AE1) protein and, more specifically, against the third loop. Moreover, this case underlines the importance of including IgA research in the initial diagnostic evaluation when a hemolytic anemia is suspected to be autoimmune and when IgG and complement are not detected on the patient's RBCs.

Agglutination Tests↗