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F Décary

Publications and source records attributed to F Décary.

At least 37 records · Page 2Linked to original sources
PubMed1992

Alloimmunization to platelet antigen HPA-1a (PIA1) is strongly associated with both HLA-DRB3*0101 and HLA-DQB1*0201.

Antibodies to the platelet HPA-1a antigen can elicit in the newborn a condition known as neonatal alloimmune thrombocytopenic purpura (NAITP). Previous studies based on RFLP analysis showed that 100% of HPA-1a-negative women who produced anti-HPA-1a antibodies (responders) were HLA-DRw52a (DRB3*0101). However, this specificity could also be found in some HPA-1a-negative women not producing anti-HPA-1a antibodies (nonresponders). We have analyzed in detail by PCR-SSOP the HLA-DR, -DQ, and -DP loci of 36 responders and 10 nonresponders. We found that while the allele DRB3*0101 was present in the vast majority of responders (91%), there were exceptions. Furthermore, the DQB1*0201 allele was found to be present in almost all responders (94%), but again was also found in nonresponders. The risk of alloimmunization to HPA-1a in an HPA-1b homozygous mother significantly increases with the presence of either allele, the odds ratio being 39.7 for DQB1*0201 and 24.9 for DRB3*0101. Sequencing of exon 2 of these two alleles from responders indicated no sequence difference when compared with the consensus sequences. This indicates that they do not represent variants when compared with the same alleles found in some nonresponders.

Alleles↗
PubMed1991

Evaluation of pediatric transfusion practice using criteria maps.

Pediatric blood transfusion practice in a tertiary-care pediatric hospital was evaluated retrospectively by using the technique of criteria mapping. A total of 630 transfusion episodes involving red cell concentrates, frozen plasma (plasma frozen within 24 hours of collection), platelet concentrates, and albumin were reviewed: 243 (86.2%) were reviewed only by a technical assistant, and 87 (13.8%) required additional physician review. Of these, 138 were red cell concentrate transfusions: 79.7 percent of that group were considered appropriate, 11.6 percent of unknown benefit/risk ratio, 5.8 percent inappropriate, and 2.9 percent impossible to evaluate. Some 246 frozen plasma transfusions were reviewed: 42.3 percent were considered appropriate, 32.5 percent of unknown benefit/risk ratio, 17.5 percent inappropriate, and 7.7 percent impossible to evaluate. A total of 139 platelet concentrate transfusions were reviewed: 64.7 percent were considered appropriate, 16.5 percent of unknown benefit/risk ratio, 10.1 percent inappropriate, and 8.6 percent impossible to evaluate. Some 107 albumin transfusions were reviewed: 90.6 percent were considered appropriate, 1.9 percent inappropriate, and 7.5 percent impossible to evaluate. The criteria maps developed for this study were easy for the technical assistant to use, and areas of appropriate and inappropriate pediatric transfusion practice were clearly identified.

Adolescent↗
PubMed1991

The immune response to the HPA-1a antigen: association with HLA-DRw52a.

Antibodies to the HPA-1a antigen can elicit a condition in the new-born known as neonatal alloimmune thrombocytopenia (NAITP). Retrospective and prospective studies have shown that there is a strong correlation between the presence of HLA-DR3, HLA-DRw52 in the mother and the antibody response to HPA-1a. HLA Class II molecules play an important role in the initiation of the immune response and it has been postulated that HPA-1a antibody production could be determined by the presence of a specific HLA Class II molecule at the surface of the antigen-presenting cell. Thirty-one HPA-1a negative women with HPA-1a antibodies (responders) and nine HPA-1a negative women without HPA-1a antibodies (non-responders) were recruited. They were studied using serological HLA Class I and Class II typing and RFLP analysis with a DR beta probe. We found that all responders had the HLA-DRw52a sub-specificity confirming recently published data. Moreover, two of the nine non-responders were also found to be HLA-DRw52a. These results suggest that the HLA-DRw52a molecule is necessary for HPA-1a antibody responsiveness but not sufficient. The results also indicate that in HPA-1a negative women the absence of HLA-DRw52a is associated with a very low risk of being antibody producers and hence, is associated with a very low risk for NAITP in their new-borns.

Antigens, Human Platelet↗
PubMed1991

Adult Still's disease: manifestations, disease course, and outcome in 62 patients.

Clinical and laboratory manifestations, disease course, outcome, and HLA associations were studied in an inception cohort of 62 subjects with adult Still's disease (ASD) from 5 Canadian universities. Twenty-eight patients (45%) were female and the median age at disease onset was 24 years. In general, the clinical features observed in our patients were identical to those in other published series. However, significantly higher frequencies of sore throat (92%), weight loss (76%), lymphadenopathy (74%), pleuritis (53%), pneumonitis (27%), and abdominal pain (48%) were noted in our patients compared to those in a recent literature review. Liver involvement with hepatomegaly (44%) or abnormal liver function tests (LFTs) (76%) was common and was responsible for the 2 deaths attributed to Still's disease in our series. Severe liver failure always occurred in conjunction with aspirin or NSAID therapy. Therefore, whether or not aspirin or other NSAIDs are used, we recommend close monitoring of LFTs in patients with ASD, especially early in the disease course. Laboratory manifestations were similar to those already reported. Leukocytosis (greater than or equal to 15,000/mm3) was present in 50 patients (81%), a normochromic, normocytic anemia (hemoglobin less than or equal to 10 g/dl) in 42 (68%), and an elevated ESR in all. The mean follow-up of the 62 patients was 70 months (range, 2-163). Twenty-one patients (34%) had a self-limited disease course, 15 (24%) an intermittent course, and 22 (36%) a chronic disease course. Four patients (6%) died, and 2 of these deaths were attributed to Still's disease. For those patients who experienced a recurrence of ASD, the flares were usually of shorter duration and milder in severity than the initial episode. No initiating factor for disease exacerbation was identified in our patients. Although 22 of 62 patients (36%) had a chronic disease course, 52 (90%) were in ARA Functional Class I, and only 4 and 2 patients were in ARA Functional Class II and III, respectively. Patients with Still's disease had higher scores than the controls on the Pain (P less than 0.01) and Physical Disability (P less than 0.05) subscales of Arthritis Impact Measurement Scales health status questionnaire. Joint radiographs performed at the follow-up evaluation disclosed typical carpometacarpal and intercarpal involvement in 16 of 39 patients. In our series, HLA-B17, B18, B35, and DR2 were significantly associated with ASD. Three significant predictors of an unfavorable outcome, either a chronic disease course or a longer time to clinical remission, were identified.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1990

Alloimmunization to the PlA1 platelet antigen: results of a prospective study.

The natural history of alloimmunization to the PlA1 platelet antigen is uncertain. We followed 50 PlA1-negative pregnant women during pregnancy and for 6 months post-partum in order to determine this natural history. The cohort of PlA1-negative women was obtained by PlA1 typing 5000 women. Three PlA1-negative women formed anti-PlA1 antibodies during this prospective study, two in pregnancy and one in the immediate post-partum period. All three PlA1 antibody producers were HLA-DR3 positive, a histocompatibility phenotype that is strongly associated with alloimmunization to the PlA1 antigen. One of the three infants delivered to these mothers was thrombocytopenic (platelet count 9 x 10(9)/l). The remaining two infants had normal platelet counts at birth (160 and 174 x 10(9)/l). The HLA-A1, -B8, -DR3 and -DRw52 phenotype frequencies in the group of PlA1-negative women who did not form PlA1 antibodies (n = 47) was similar to that found in their husbands, and that expected in a normal Caucasian population. From our data we estimate that alloimmunization to the PlA1 antigen occurs in approximately one out of every 1000 pregnancies in a Caucasian population. It is important to recognize that not all pregnancies in which a mother has formed PlA1 alloantibodies will result in the delivery of a thrombocytopenic infant. These findings are relevant to programs designed to either prevent alloimmunization to the PlA1 antigen (through passive administration of anti-PlA1 immunoglobulin to at-risk PlA1-negative mothers), or to identify women at risk of delivery of thrombocytopenic infants (by antenatal screening to detect women alloimmunized to the PlA1 antigen).

ABO Blood-Group System↗
PubMed1989

HLA-DR beta, -DQ alpha, and -DQ beta restriction fragment length polymorphisms in multiple sclerosis.

Restriction fragment length polymorphism (RFLP) studies were performed on DNA from unrelated Caucasian patients with multiple sclerosis (MS) using cDNA probes to the HLA class II genes DR beta, DQ alpha, and DQ beta. In a study of 34 patients and 34 controls who were not matched for DR type, we found that the DQ beta allele-specific RFLP or allogenotype, termed DQ beta lb, which corresponds at the molecular level to the DQwl serotype, is preferentially associated with MS. A significant disease association with DR2 was demonstrated by serology but this was not confirmed using DR2/Dw2-specific RFLPs. We suggest that DQ beta lb is largely responsible for HLA-associated susceptibility to MS and that the apparent MS-DR2 serological association is due to the strong linkage disequilibrium between DR2 and DQ beta lb. Homozygosity of one of the two allelic bands of the DX alpha gene, usually termed the DX alpha lower (DX alpha L) band (which cross-hybridizes with the DQ alpha probe), correlated with reduced susceptibility to MS. Similarly a 5.3 kb band identified by the DQ alpha probe in Mspl digests showed a negative correlation with MS. In an analysis of 27 DR2+ controls and 26 DR2+ patients it was found that these individuals all had DR2/Dw2-specific RFLPs and all had identical DR2/Dw2-associated DQ beta (DQ beta lb) and DQ alpha (DQ alpha lb) allogenotypes. We detected no polymorphisms of DR beta, DQ alpha, or DQ beta genes among the DR2+ MS patients which distinguished them from normals.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1989

[Delayed hemolytic transfusion reaction caused by an anti-U].

Delayed hemolytic transfusion reactions due to anti-U are rare, only two (2) cases having been reported in the literature. We now report a third case: a multiparous black woman without any transfusion history was admitted to hospital for severe microlytic anemia (31 g/l). The patient was group AB negative, the direct antiglobulin test was negative and an anti P1 cold allo-antibody was present in her serum. Five A, Rh negative, P2 packed red cells were cross-marched with the sample obtained at admission on January 8, 1988. She was transfused on January 8, 9, 10, 11 and 12. On the 12th of January her hemoglobin level reached 125 g/l. On January 13, the patient presented clinical signs of hemolysis and her hemoglobin fell to 60 g/l within 24 hours. On January 15, the direct antiglobulin test was positive and an antibody found in her serum was reactive with all the red cells of the commercial panel. The sample was referred to our red cell serology reference laboratory. The phenotype of the pre-transfusion sample was found to be Fy(a-b-) M, N, S-s-U-. An anti-U was detected in the eluate and the serum. The patient was transfused with two (2) units of O-P2, U-red cells obtained from the American Red Cross, Syracuse, and her hemoglobin reached 90 g/l within 48 hours. This is the third reported case of a delayed hemolytic transfusion reaction due to anti-U. This case illustrates the need to perform cross-matches with samples obtained within 48 hours of the scheduled transfusion for patients who have been transfused with blood in the preceding 3 months. Also, this case emphasises the need to recruit U negative blood donors for the Canadian rare donor file.

Anemia↗
PubMed1987

Use of platelet concentrate in eastern Ontario.

To better understand the reasons for the increasing use of platelet concentrate in Canada, we undertook a 4-month study of platelet concentrate transfusion in six eastern Ontario hospitals in 1985. A total of 4801 units of platelet concentrate were transfused on 687 occasions to 303 patients; the average number of transfusions per patient was 2.3, the average number of units per transfusion 7.0 and the average number of units per patient 15.8. The cardiovascular service used the largest proportion of units (28%), aortocoronary bypass grafting being the most common procedure. The mean pretransfusion platelet count for the medical and oncology services was about 30.0 X 10(9)/L, compared with 155.5 X 10(9)/L for the cardiovascular service. An increment in platelet count 1 hour after transfusion was noted with 238 (75%) of the transfusions for which the data were available; the average increment was 3.4 X 10(9)/L per unit of platelet concentrate transfused. When the data for patients who did not respond were excluded, the average increment was 6.9 X 10(9)/L. Single-donor platelet concentrate was requested for only half of the transfusions to which no response was detected. The current medical literature supports the appropriate use of platelet concentrate in patients with thrombocytopenia due to chemotherapy, but prophylactic platelet transfusion for patients undergoing cardiovascular bypass procedures is being questioned. We advise continued surveillance of the use of these products and re-evaluation of the aims of platelet transfusion therapy.

Blood Transfusion↗
PubMed1987

Airways disease in rheumatoid arthritis patients. One element of a general exocrine dysfunction.

Airflow limitation is a frequent finding in patients with rheumatic diseases. We have previously suggested that it is associated with autoimmune exocrinopathy in Sjögren's syndrome. To compare clinical features of patients with and without airways dysfunction and to further test the hypothesis of a link between airways disease and exocrinopathy, we prospectively studied 2 groups of 15 lifetime nonsmoker female patients with seropositive rheumatoid arthritis (RA). The 2 groups were similar in their clinical and immunologic features, but differed in terms of airways function. Salivary, lacrimal, and sweat gland dysfunction were significantly more prevalent or severe in the group with airways disease. Antinuclear antibodies were also more prominent in the patients with airways disease, but antibodies against RNP, SS-A, SS-B, and double-stranded DNA were not present in these patients. HLA-DR4 was found in 80% of the RA patients with airways disease and in 57% of those without airways disease. HLA-B8 and DR3 were equivalently distributed in both groups. This prospective study further documents the existence of small airways disease in RA and supports the view that autoimmune exocrinopathy predisposes to its expression.

Adult↗
PubMed1987

Clinical and sleep laboratory study of narcoleptic symptoms in multiple sclerosis.

Seventy white patients with a diagnosis of MS and typed for their HLA-A, B, C, and DR were studied. A clinical interview and a questionnaire were used to evaluate the presence of narcoleptic symptoms. The prevalence of sleep attacks, cataplexy, and sleep paralysis was significantly elevated among these patients. However, no difference was seen between DR2 and non-DR2 subjects with regard to the incidence of narcoleptic symptoms. Nine DR2 patients complaining of both sleep attacks and cataplexy were studied in the sleep laboratory for five consecutive naps, but no polygraphic evidence of narcolepsy was found.

Adult↗
PubMed1986

HLA antigens in narcolepsy and idiopathic central nervous system hypersomnolence.

Several studies have shown familial incidence of narcolepsy and idiopathic central nervous system (CNS) hypersomnia. HLA antigen studies performed in mongoloid and caucasoid narcoleptic patients on the A, B, and C loci have yielded conflicting results. The aim of this study is to document a possible association between the HLA system, including the DR locus and excessive daytime somnolence. Thirty-one narcoleptic patients and 10 idiopathic hypersomniac patients were selected and typed for 54 HLA antigens. A family with narcoleptic members in 3 generations was also studied. HLA-DR2 was found in 100% of narcoleptic patients. The frequency of HLA-A3 and B7, which are in linkage disequilibrium with DR2 was also increased in this group. Idiopathic hypersomniac patients showed an increase of HLA-Cw2, DR5, and B27, three antigens known to be in linkage disequilibrium. In the family study, narcoleptic patients were also HLA-DR2; moreover, 3 subjects, one of whom was narcoleptic, were HLA-DR2 as a result of recombination (i.e., genetic crossing-over). These results locate the hypothetic gene associated with narcolepsy more precisely, and indicate that narcolepsy and idiopathic CNS hypersomnolence are two different entities.

Adult↗