Antibody Screening Test Research Articles

False-positive and indeterminate human immunodeficiency virus test results in pregnant women.

Guidelines from the Centers for Disease Control and Prevention, Atlanta, Ga, recommend that all pregnant women be offered human immunodeficiency virus (HIV) testing to ensure that they have the opportunity to use currently available therapeutic interventions to reduce the risk infecting their offspring with HIV. These recommendations have resulted in an increased number of low-risk women being tested and a significant rise in the percentage of false-positive results from HIV antibody screening tests and ambiguous (indeterminate) findings from confirmatory tests. Women receiving such results are generally in emotional turmoil yet must make treatment choices if they prove to be infected. This article provides guidelines to help general medical practitioners to understand the nature of HIV testing, to assess a woman's infection status when initial tests are ambiguous, and to determine when treatment is appropriate.

Optimal blood donation screening annotation.

Optimal blood donation screening annotation.

False Positivity in a Cyto-ELISA for Anti-Endothelial Cell Antibodies Caused by Heterophile Antibodies to Bovine Serum Proteins

ELISAs with fixed endothelial cells or cell lines are widely used screening tests for anti-endothelial cell antibodies (AECAs), but spurious increases occur. We examined interferences by heteroantibodies and means to eliminate them. AECAs were measured by ELISA on fixed layers of the human endothelial cell line, EA.hy 926, in a panel of 60 patient serum samples diluted in bovine serum albumin. Heteroantibodies against fetal calf serum (FCS) proteins were demonstrated and characterized in an ELISA-the interference assay-that used FCS-coated plates and Tween 20-containing buffer as blocking agent and sample diluent, as well as by immunoblotting. In 12 of 60 patient serum samples, spurious increases of AECA titers were produced by endogenous antibodies reacting with FCS proteins from culture medium that were coated onto the solid-phase at the time of cell plating. This mechanism of interference was supported experimentally by exposing extracellular matrix, varying cell density, and incubating wells with FCS alone. The heterophile antibodies were mainly IgG and IgA, and in inhibition experiments, they recognized serum proteins from goat, sheep, and horse. Washing cells free of FCS before plating, or adding FCS (100 mL/L) to the patient sample diluent eliminated spurious signals from all 30 tested sera, but the latter method had practical advantages. Antibodies against animal serum proteins are a frequent cause of erroneous results in cyto-ELISAs. The interference can be eliminated by simple antibody absorption in FCS-containing dilution buffer.

Large-scale use of red blood cell units containing alloantibodies

Abstract Many transfusion services are reluctant to accept red blood cell (RBC) units containing antibodies. We evaluated the impact of accepting routine shipments of our region’s inventory of alloantibody-positive RBC units over a 4-month period. All patients’ samples received up to 30 days after transfusion of such units were evaluated for the presence of passively acquired antibody, and labor and reagent costs were determined. During the study period, we received 259 alloantibody-containing RBC units, and 253 of these were transfused to 187 patients. Follow-up samples were received on 99 of these187 patients, and 10 of these patients had detectable passive antibody in posttransfusion antibody screening tests. Two patients had anti-C and -D and eight patients had anti-D. Due to our negotiation of a small discount for antibody-containing units and the use of 20 units based on labeled phenotype rather than antigen typing in our laboratory, we experienced a net savings of $3814 over the 4-month period. This savings was achieved despite some additional costs incurred, including costs of data entry and additional testing on patients’ samples. We concluded that large-scale use of RBC units from donors with alloantibodies is safe and likely to have a minimal impact on a busy transfusion service’s workload and costs. Furthermore, nationwide use of such units would help alleviate projected blood shortages. Immunohematology 2000;16:120–123.

Comparison of tube and gel techniques for antibody identification

There are several methods for antibody detection and each technique has advantages and limitations. We compared the performance of the tube (polyethylene glycol–indirect antiglobulin test [PEG-IAT]) and gel test technique for antibody identification. From January to May 1999, we performed antibody screening tests by gel and tube techniques on 10,123 random blood samples submitted to our reference laboratory. Six hundred and twentyeight (6.2%) reactive samples were tested for antibody specificity by both methods. One hundred and ninety-six were reactive only by gel: 25 anti-D, 33 anti-C, 76 anti-E, 13 anti-c, 5 anti-e, 18 anti-K, 7 anti-Jka, 2 anti-Dia, 3 anti-S, 8 combination Rh antibodies (1 with anti-K), and 6 other antibody specificities. Two samples were reactive only by PEG-IAT: 1 anti-K and 1 anti-Dia. Four hundred and thirty were positive by the two methods: 156 anti-D, 9 anti-C, 68 anti-E, 15 anti-c, 6 anti-e, 61 anti-K, 12 anti-Jka, 17 anti-Dia, 5 anti-S, 73 combination Rh antibodies (2 with anti-K), and 8 other antibody specificities. Based on this study, the gel test is more sensitive (p <.01) than the tube test for identifying potentially clinically significant antibodies. Immunohematology 2000; 16:138–141.

Micro‐Column Affinity Test and Gel Test: Comparative Study of Two Techniques for Red Cell Antibody Screening

Abstract Background and Objectives: We describe the results of a comparative evaluation of a gel test (ID Micro Typing) and a micro‐column affinity test (MCAT, Cellbind Screen) for red cell antibody screening and identification under routine conditions. Materials and Methods: 3,000 serum samples of patients from the Mannheim University Hospital were tested in parallel by means of the gel test and the MCAT, using the low‐ionic‐strength‐saline indirect antiglobulin test and the protein G affinity technique, respectively. Test cells used were the same in all tests. In addition, we performed titration studies with all detected antibodies as well as with 59 frozen sera containing antibodies of known specificity. Results: A total of 154 antibodies (5.1%) were detected, 149 by gel test and 147 by MCAT. The overall sensitivity and specificity of the gel test was 96.8 and 96.5% and of the MCAT 95.5 and 97.2%. No significant differences between the gel test and MCAT were found when the titer scores of all 213 (fresh and frozen) antibodies were used to check the results. The mean scores for the gel test and the MCAT were 26.8 and 28.5, respectively. For anti‐Fya and anti‐Kell, a significantly higher titration score could be obtained in the MCAT, whereas anti‐Lua showed a significantly higher score with the gel test. Conclusion: For the screening of unexpected red blood cell antibodies, the MCAT is as sensitive as the gel indirect antiglobulin test. The sensitivity and specificity of the two systems are more or less the same although it seems that lgM antibodies are better detected by the gel test.

Micro–Column Affinity Test and Gel Test: Comparative Study of Two Techniques for Red Cell Antibody Screening

Background and Objectives: We describe the results of a comparative evaluation of a gel test (ID Micro Typing) and a micro–column affinity test (MCAT, Cellbind Screen) for red cell antibody screening and identification under routine conditions. Materials and Methods: 3,000 serum samples of patients from the Mannheim University Hospital were tested in parallel by means of the gel test and the MCAT, using the low–ionic–strength–saline indirect antiglobulin test and the protein G affinity technique, respectively. Test cells used were the same in all tests. In addition, we performed titration studies with all detected antibodies as well as with 59 frozen sera containing antibodies of known specificity. Results: A total of 154 antibodies (5.1%) were detected, 149 by gel test and 147 by MCAT. The overall sensitivity and specificity of the gel test was 96.8 and 96.5% and of the MCAT 95.5 and 97.2%. No significant differences between the gel test and MCAT were found when the titer scores of all 213 (fresh and frozen) antibodies were used to check the results. The mean scores for the gel test and the MCAT were 26.8 and 28.5, respectively. For anti–Fy^a and anti–Kell, a significantly higher titration score could be obtained in the MCAT, whereas anti–Lu^a showed a significantly higher score with the gel test. Conclusion: For the screening of unexpected red blood cell antibodies, the MCAT is as sensitive as the gel indirect antiglobulin test. The sensitivity and specificity of the two systems are more or less the same although it seems that IgM antibodies are better detected by the gel test.

A rapid latex agglutination test for detection of leptospiral antibodies

A rapid semi-quantitative latex agglutination test (LAT) has been standardized for the detection of leptospiral antibodies in serum samples of man and animals. The efficacy of the LAT was compared with the plate enzyme linked immunosorbent assay (ELISA). A total of 276 human serum samples were analyzed by both LAT and ELISA and percentage positives were 84.8 and 85.9%, respectively. Similarly, of 65 animal samples tested, 63.1 and 69.2% positivity were observed in LAT and ELISA, respectively. Even though the ELISA test was slightly more sensitive than LAT, the rapidity, simplicity and economics of the LAT were found to fulfill the requirements of a screening test for leptospiral antibodies.

Screening Tests for Antinuclear Antibodies (ANA): Selective Use of Central Nuclear Antigens as a Rational Basis for Screening by ELISA

Rational, fully automated ELISA screening tests for ANA have become accessible for routine use. Full length, recombinant or purified naturally expressed antigens can be selected to deliver well defined screening tests, designed to detect ANAs of established clinical significance, while unknown specificities with no clear biological impact are omitted. By comparing results of ANA screening by immunofluorescence (IIF) on tissue section with HEp-2 cells, a correlation of 88% was revealed, while 86% of HEp-2-positive sera bound tissue sections. Eighty-nine percent of HEp-2 ANA-positive sera bound in ANA ELISA I. Seventy-five percent of ANAs detected in ELISA I also bound in ELISA II. These correlations were statistically significant. ANAs detected in ANA ELISA I were all detected upon retesting in both ANA screening ELISA systems, and also by antigen-specific ELISAs. Specific ANAs defined by ELISA, immunodiffusion or Crithidia tests were detected in both ANA ELISA tests. These data demonstrate that most ANAs detected by immunofluorescence tests contain a dominating repertoire of specificities covered by the ANA ELISA systems. The sensitivity of the different ELISA tests can easily be adjusted to internationally defined consensus levels, and screening for ANA using both ELISA systems detects expected ANA specificities in ongoing international quality assessment programs.

Revisiting the issue: can the reading for serologic reactivity following 37 degrees C incubation be omitted?

Omitting the 37 degrees C reading from screening tests for unexpected antibodies results in failure to detect some Rh, K, and Jk agglutinins of potential significance (wanted positives). However, this measure avoids unwanted positive tests due to cold agglutinins. Using data from prior publications, actual risk calculations (ARCs) were made to predict the risk of eliminating the 37 degrees C reading, pretransfusion direct antiglobulin test (DAT), and routine indirect antiglobulin crossmatch (IAT-XM). ARCs used the equation: wanted positives missed x 0.34 (or 0.80) x 5 x percent antigen-positive, where 0.34 = percent of patients transfused (ARCs for 37 degrees C reading and DAT); 0.80 = percent of crossmatched patients transfused (ARCs for IAT-XM); 5 = average number of units transfused. Following elimination of the 37 degrees C reading, the impact of this change on patient care was monitored. Antibody detection and identification data and transfusion reaction reports for 6 months after the change were reviewed. Recently transfused patients with new antibodies were evaluated for immune hemolysis by review of clinical and laboratory data. The findings were compared with those from the same dates of the preceding year. The risk of transfusing incompatible blood by eliminating the DAT, IAT-XM, and 37 degrees C reading is approximately 1:13,000, 1:2,000, and 1:2,400 units transfused, respectively. The cumulative risk from eliminating all three tests is approximately. 1 :1,000 units. With respect to the 37 degrees C reading, there were no differences between the pre-change and post-change study periods in the incidence of reported transfusion reactions or cases of immune hemolysis associated with newly formed antibodies. However, unwanted positive tests decreased from 162 to 61 following elimination of the 37 degrees C reading. This represents a decrease of 20 percent in the number of samples requiring antibody identification annually. Eliminating the 37 degrees C reading from pretransfusion antibody screening tests imposes less risk than omitting the routine IAT-XM, and it avoids the time and costs of evaluating unwanted positive tests, thus reducing expenditures and delays in patient care.

Detection of Rare Cases of HTLV-I and -II Infections and High Numbers of HTLV-Seroindeterminate Results in Bavarian Blood Donors

Background: In order to evaluate the prevalence of human T-cell lymphotropic virus type I and II (HTLV-I/-II) infections in Germany, the Bavarian blood donor population was screened. Material and Methods:Between 1991 and 1994 around 1.5 million donations from about 375,000 blood donors of the Bavarian Red Cross (BRK) were tested for HTLV-I/-II in an antibody screening test. Sera repeatedly reactive in the screening test at the BRK blood bank were further assayed in additional enzyme-linked immunosorbent assays (ELISA), Western blot (WB) and radioimmunoprecipitation assay (RIPA). Selected donors were analyzed by polymerase chain reaction (PCR). Results:Only 4 HTLV-I/-II infections could be confirmed by WB and by RIPA, indicating a seroprevalence of 0.001%. Three positive donors were American soldiers and the fourth one was a German woman. Out of 609 sera reactive in at least two antibody screening tests, only 4 could be confirmed in WB as HTLV-I or -II positive. However, reactivity of these sera appears not to be related to an HTLV-I or -II infection, as shown by selected samples testing negative by RIPA and PCR. Conclusions:HTLV-I/-II seroprevalence in Bavarian blood donors is very low which implies that a general testing of all blood donations should not be recommended. However, donors with sexual partners from HTLV-endemic regions should be tested. Concerning serological diagnosis, we would suggest to modify the WHO-based interpretation criteria in countries with low HTLV prevalences: Only sera with antibodies to 1 or 2 Gag andthe 2 recombinant Env proteins should be considered HTLV positive.

Prevalence Rate of Red Blood Cell Antibodies during Gravidity in the Federal Province of Salzburg

Background: One of the aims of maternity care is the timely recognition of the risk of hemolytic disease of the newborn (HDN) by specific screening for antibodies. Although the antibody screening test (ABST) is recommended as an obligatory measure during gravidity in the draft of the Austrian guidelines for blood group serology and transfusion medicine part IV, the Austrian ordinance concerning the mother-child screening card provides for merely a confirmation of the blood group, though no screening for antibodies. Material and Methods:Over a period of 46 months (January 1, 1994 to October 31, 1997) the ABSTs of 24,538 (19,285 D-positive and 5,253 D-negative) pregnancies were evaluated in the province of Salzburg. Results:The prevalence of antibodies in pregnancies of D-positive women amounted to a total of 0.47%, that of D-negative women to 2.41%. HDNs being in need of transfusion were found in 0.25% of the children with D-negative and in 0.02% of children with D-positive mothers.

抗ＨＩ抗体による寒冷凝集素症にＩＴＰを合併したＥｖａｎｓ症候群の１例

A 70-year-old female was admitted with anemia and thrombocytopenia. Her blood type was B Rho (+). Her RBC was 250×104/μl, Hb7.8g/dl, Ht 23.2%, Retic. 55‰, WBC 2900/μl, T. bil 0.3mg/dl, LDH 917U/L, and Haptoglobin <10mg/dl. Cold agglutinin titer was×1024, direct Coombs test (-), indirect Coombs test (4+). Antibody screening test in saline revealed serum agglutinated adult O cells (4+) (×512), adult i cells (+) (×64), cord cells (-) and B cells (-), leading to an antibody diagnosis of anti-HI antibody. She subsequently developed thrombocytopenia (16×103/μl) and PAIgG was 54.8ng/107 platelets, giving a diagnosis of idiopathic thrombocytopenic purpura together with cold agglutin disease. The presence of cold agglutinin disease due to anti-HI antibody and development of ITP indicated this to be a case of Evans syndrome. Hemolytic anemia due to anti HI antibody is very rare, as is the association of ITP with cold agglutination disease.

Clinical evaluation of a solid-phase test for red cell antibody screening of pregnant women.

The aims of this study were to evaluate the results of a new solid-phase screening test for detecting atypical red cell (RBC) antibodies in a large number of pregnant women and to compare these results to the clinical outcome of the newborn. A total of 38,700 infants born in Stockholm were studied retrospectively. Of these infants, 18,500 were born to pregnant women screened with the solid-phase test. Data were collected on all newborns with a positive direct antiglobulin test (DAT) and on infants requiring an exchange transfusion or a blood transfusion. These data were correlated to the screening results for the mothers. Of 409 DAT-positive newborns, a serologic explanation for the positive DAT was found in 349. Three hundred four cases were due to ABO incompatibility between mother and child; 19 of these infants needed an exchange transfusion. Forty-two cases were due to unexpected maternal RBC antibodies; 11 of these infants were given an exchange transfusion. All 11 were identified before birth. Three other infants had DAT-positive tests due to ABO incompatibility and to unexpected maternal RBC antibodies. ABO incompatibility is a major indication for exchange transfusion in DAT-positive newborns. There was no evidence that the solid-phase screening test had failed to detect any clinically significant RBC antibodies. Finally, the results of this study do not indicate a need for routine screening of D+ women more than once during each pregnancy.

Effects of maternal dietary avoidance during lactation on allergy in children at 10 years of age

This study investigated the long-term effects of maternal dietary avoidance during lactation on the occurrence of atopic symptoms, development of immunoglobulin E (IgE) antibodies to food and inhaled allergens and occurrence of positive skin-prick tests (SPT) in 65 children with a family history of atopy whose mothers adhered to a diet devoid of eggs, cow's milk and fish during the first 3 months of lactation (D group) and in a matched group of 50 children with mothers not practising such a diet (ND group). The diets of the D and ND children were similar. All children attended 7 follow-ups from the age of 3 months to the age of 10 y. After the first follow-up there was a 100% retention of participants. The results of the seventh follow-up at 10 y are presented. Total IgE values and IgE antibodies to seven food and seven inhaled allergens were determined by the Phadebas IgE CAP and the Phadebas RAST, respectively. SPT were conducted for five food and seven inhaled allergens. High rates of atopic symptoms occurred in both groups, but there were no differences between the groups. Sensitization to the three foods avoided by the mothers during lactation was similar, but the overall test reactivity to foods was lower in the D group. Sensitization to inhaled allergens was similar in the two groups. During the 10 y of follow-up, there was no difference between the groups in the occurrence of indoor furred animals, tobacco smoking, changes in heredity for atopy or development of total IgE, but a higher rate of maternal sensitization was found in the ND group, as judged by a screening test for IgE antibodies to inhalants (Phadiatop). The results do not support general recommendations to implement prophylactic maternal dietary avoidance during lactation in allergy-prone families.

Comparison of the enzyme‐linked immunosorbant assay III, recombinant immunoblot third generation assay, and polymerase chain reaction method in the detection of hepatitis C virus infection in Haemodialysis patients

Hepatitis C virus (HCV) serotyping assays have evolved from simple antibody screening tests to complex RNA-based qualitative and quantitative methods. The objective of this study was to compare the HCV screening results from 161 patients in long-term maintenance haemodialysis (HD) as assessed by the recently developed Enzyme Linked Immunosorbant Assay III (ELISA III), confirmed by the Recombinant Immunoblot 3rd generation assay (RIBA 3rd) and determined by the qualitative HCV reverse transcription polymerase chain reaction (RT-PCR) method. One hundred sixty-one HD patients were tested for the presence of anti-HCV antibodies by the ELISA III and confirmed by the RIBA 3rd. HCV RNA was determined by an HCV RT-PCR method. All reported results that were designated as discrepant, anti-HCV (+) and/or HCV RNA (+) were further investigated by means of a quantitative HCV RT-PCR assay. Reported results obtained from ELISA III and qualitative RT-PCR assays were HCV positive for 16/161 patients (9,93%) and these were designated as anti-HCV (+)/HCV RNA (+). Subsequently, these 16 anti-HCV positive/161 HD patients were confirmed by the RIBA 3rd. Three individuals anti-HCV (–)/RIBA (+)/ HCV RNA (–)], the viral load that was reported from the quantitative RT-PCR was less than the assay detection level (< 2,000 viral copies/ml). In view of previous observations, our findings suggest that ELISA III remains still a highly reliable and valuable assay. However, despite the cost, the combination of both ELISA III and qualitative RT-PCR allows a definitive classification on HCV diagnosis. J. Clin. Lab. Anal. 13:122–125, 1999. © 1999 Wiley-Liss, Inc.

Comparison of the enzyme-linked immunosorbant assay III, recombinant immunoblot third generation assay, and polymerase chain reaction method in the detection of hepatitis C virus infection in Haemodialysis patients

Hepatitis C virus (HCV) serotyping assays have evolved from simple antibody screening tests to complex RNA-based qualitative and quantitative methods. The objective of this study was to compare the HCV screening results from 161 patients in long-term maintenance haemodialysis (HD) as assessed by the recently developed Enzyme Linked ImmunosorbantAssay III (ELISA III), confirmed by the Recombinant Immunoblot 3rd generation assay (RIBA 3rd) and determined by the qualitative HCV reverse transcription polymerase chain reaction (RT-PCR) method. One hundred sixty-one HD patients were tested for the presence of anti-HCV antibodies by the ELISA III and confirmed by the RIBA 3rd. HCV RNA was determined by an HCV RT-PCR method. All reported results that were designated as discrepant, anti-HCV (+) and/or HCV RNA (+) were further investigated by means of a quantitative HCV RT-PCR assay. Reported results obtained from ELISA III and qualitative RT-PCR assays were HCV positive for 16/161 patients (9,93%) and these were designated as anti-HCV (+)/HCV RNA (+). Subsequently, these 16 anti-HCV positive/161 HD patients were confirmed by the RIBA 3rd. Three individuals anti-HCV (-)/RIBA (+)/HCV RNA (-)], the viral load that was reported from the quantitative RT-PCR was less than the assay detection level (< 2,000 viral copies/ml). In view of previous observations, our findings suggest that ELISA III remains still a highly reliable and valuable assay. However, despite the cost, the combination of both ELISA III and qualitative RT-PCR allows a definitive classification on HCV diagnosis.

Seroprevalence of HTLV-I and HTLV-II among a cohort of HIV-infected women and women at risk for HIV infection. Women's Interagency HIV Study.

To determine the seroprevalence of, and risk factors for, HTLV-I and HTLV-II infection among HIV-infected women and women at high risk for HIV infection. Cross-sectional analysis of baseline data for women enrolled in the prospective Women's Interagency HIV Study (WIHS). From October 1994 through November 1995, 2657 women from five metropolitan areas in the United States (Chicago, Los Angeles, New York City [two sites], Northern California, and Washington DC) were enrolled in WIHS. An interview-based survey collected data on demographics, behavior, and medical history. HTLV-I and HTLV-II determinations were made using a combined HTLV-I/HTLV-II indirect immunofluorescent antibody (IFA) screening test, an IFA titration specificity test, and individual HTLV-I and HTLV-II confirmatory Western blots. Fisher's exact tests and logistic regression were used to determine univariate and multivariate independent predictors for HTLV-II infection. Of 2625 women enrolled in WIHS with confirmed HIV results, 2487 (95%) were tested for HTLV-I and HTLV-II. Of these, 241 (10%) were HTLV-II-seropositive and 13 (0.5%) were HTLV-I-seropositive. On multivariate analysis, independent predictors of HTLV-II infection included injection drug use (OR = 5.2; p < .001), black race (OR = 3.6; p < 0.001), age >35 years (OR = 3.3; p < .001) and a history of sex with a male injecting drug user (OR = 1.9; p < .001). Among women infected with HIV, the seroprevalence of HTLV-II was 11% compared with 6% for women at risk for HIV but not infected (p < .001). However, HIV was not an independent predictor of HTLV-II infection in multivariate analysis. This cross-sectional analysis confirms that HTLV-II is found commonly in HIV-infected women and uninfected women at risk for HIV in major urban areas throughout the United States and that HTLV-II is far more common than HTLV-I in these populations. Although injecting drug use is most strongly associated with HTLV-II infection, sexual transmission likely contributes to the high HTLV-II seroprevalence in this cohort.

Effects of HLA matching on the results of kidney transplantation (81 case reports).

Human leukocyte antigen (HLA) allo-immunization is caused by various events such as blood transfusions, pregnancies, or organ transplantations, which can lead to sensitization. In this retrospective study, we evaluated different sensitization models and their effects on panel-reactive antibody (PRA) profiles of renal transplantation candidates.Anti-HLA class I/II antibody screening tests were performed in 906 renal transplantation candidates with the use of a microbead-based assay (Luminex).Two hundred ninety-seven (32.8%) of the patients were determined as positive in terms of PRA, and 609 (67.2%) were negative. Sensitized and non-sensitized patients were compared separately in terms of each sensitization type. The anti-HLA class I, II, and I+II positivity rates in patients sensitized only by blood transfusion were 13.1%, 6.3%, and 14.1%, the rates with pregnancy sensitization were 35.5%, 29%, and 45.2%, and rates with previous transplantation sensitization were 15.6%, 34.4%, and 38.9%, respectively. Prevalence of PRA positivity was significantly higher in patients with previous pregnancy than with transplantation and transfusion (odds ratio, 1.003; 95% confidence interval, 0.441–2.281; P = .031). The risk of developing HLA class I antibodies was higher in pregnancies (P < .001), and the risk of developing anti-HLA class II antibodies was higher in patients who had undergone a previous transplantation (P < .001). The rate of developing HLA-B antibodies in patients sensitized by pregnancy were significantly higher compared with sensitization after transfusion (P = .015), as was the rate of developing HLA-DQ antibodies in patients sensitized by previous transplantation compared with sensitization through pregnancy (P = .042).In patients who are waiting for kidney transplantation, sensitization by pregnancy and transplantation have a significant impact on development of HLA class I and class II antibodies.

SCREENING TESTS FOR COELIAC DISEASE IN INDIAN CHILDREN

F30 Coeliac disease is a treatable cause of chronic diarrhoea and failure to thrive and is not restricted to developed countries. In this study patients suspected of having coeliac disease who presented to the All India Institute of Medical Sciences, New Delhi, were investigated using antibody screening tests (ELISA - IgA/IgG anti-gliadin antibody [AGA]. Immunofluorescence (for IgA) endomesial antibody [EMA] using monkey oesophagus [MO] and human umbilicus (HU), & antireticulin antibody [ARA] in small intestinal biopsy. Thirty four cases 23M:11F, median age 6 years, range 2 - 12) were studied over a 13 month period. 16 were EMA +ve using MO of which 15 (94%) were +ve on HU; -ve results were identical using either tissue. For these 16 cases- 14 (88%) were ARA +ve. IgA and IgG AGA were +ve in 12 (75%) and 13(81%) respectively. Of the 18 -ve EMA cases 1 was IgA and 2 were IgG AGA +ve, none were ARA +ve. Taking, the MO EMA as the gold standard the sensitivity/specificity of the other tests were 75%/94% for IgA AGA. 81%/89% for IgG AGA. 94% for HU EMA, and 88%/100% for ARA. Small intestinal biopsies were available in 17/34 cases of which 8 appeared typical for coeliac disease (2 were -ve for all antibody tests. 6 were EMA +ve. 4 IgA and 5 IgG AGA +ve) and 9 were normal or mildly abnormal(all EMA -ve. 1 IgA-AGA +ve, and 1 IgG AGA +ve). Thus, EMA using MO or HU appears to be a useful screening test for coeliac disease in Indian children. IgA and IgG AGA, although simple to use as an ELISA test, are not as sensitive as EMA. EMA opens the way for screening sections of the population who may otherwise not present to a paediatric gastroenterologist.