Observing many researchers using the same data and hypothesis reveals a hidden universe of uncertainty

This study explores how researchers' analytical choices affect the reliability of scientific findings. Most discussions of reliability problems in science focus on systematic biases. We broaden the lens to emphasize the idiosyncrasy of conscious and unconscious decisions that researchers make during data analysis. We coordinated 161 researchers in 73 research teams and observed their research decisions as they used the same data to independently test the same prominent social science hypothesis: that greater immigration reduces support for social policies among the public. In this typical case of social science research, research teams reported both widely diverging numerical findings and substantive conclusions despite identical start conditions. Researchers' expertise, prior beliefs, and expectations barely predict the wide variation in research outcomes. More than 95% of the total variance in numerical results remains unexplained even after qualitative coding of all identifiable decisions in each team's workflow. This reveals a universe of uncertainty that remains hidden when considering a single study in isolation. The idiosyncratic nature of how researchers' results and conclusions varied is a previously underappreciated explanation for why many scientific hypotheses remain contested. These results call for greater epistemic humility and clarity in reporting scientific findings.

P–695 Establishing predictors of the mode of conception in fertility patients presenting with a clinical pregnancy

Study question

What are the predictors for pregnancies conceived spontaneously (SC), by ovulation induction+/-insemination (OI±IUI) or via In-Vitro Fertilization(IVF), and what proportion of pregnancies were conceived with each method?

Summary answer

Pregnancies were conceived by SC(27.7%), OI±IUI(33%) or IVF(39.2%).Unexplained infertility positively-predicted SC and OI±IUI-conceptions. Male factor-infertility demonstrated the opposite trend, positively predicting IVF. Endometriosis negatively-predicted SC.

What is known already

Spontaneous conception (SC) occurs regularly among infertility patients. Most studies have evaluated predictors of pregnancy among women with infertility who were trying to conceive. Few studies have addressed the role of different factors on the mode of conception in infertility patients who were pregnant. Factors found in some studies to be related with a SC were younger female age, shorter duration of infertility, fewer failed IVF cycles, and diagnosis of unexplained-infertility.

Study design, size, duration

We conducted a retrospective cohort study at a University fertility-center over a six-month period in 2019 and 2020. We reviewed viability scans of 285-patients. Mode of conception was recorded as Spontaneous, OI±IUI, or IVF. Patients’ demographics, obstetric and fertility diagnosis as well as base-line hormones and ovarian reserve testing were extracted to calculate predictors for the mode of conception. Pregnancy was defined as an intra-uterine fetal sac on a transvaginal ultrasound in the 1st-trimester.

Participants/materials, setting, methods

Parametric analysis was done using ANOVA and Tukey’s post-hoc test. Nonparametric analysis was performed using the chi-square test. Predictors of the mode of conception were calculated by multivariate regression analysis using the variables not in the equation model including the following parameters: male and female age, gravidity, parity, ectopic-pregnancies, infertility diagnosis, baseline serum: FSH, estradiol, TSH, AMH, and AFC. Data is presented as mean ±SD or percentage. P < 0.05 was significant. IRB approval was obtained.

Main results and the role of chance

79 (27.7%) of pregnancies were SC, 94 (33%) resulted from OI±IUI, and 112 (39.2%) from IVF. Demographics didn’t differ between the groups including: female age(p = 0.06), male age(p = 0.79), gravidity (p = 0.47), parity(p = 0.7), ectopic-pregnancies(p = 0.07), baseline serum FSH(p = 0.29), estradiol(p = 0.65), TSH(p = 0.56), AMH(p = 0.42), and AFC(p = 0.06). Infertility diagnoses differed when comparing SC, OI±IUI and IVF conceptions respectively: Unexplained (22.7%, 22.3%, 15.1%, p = 0.03), Male-Factor(MF) (25%, 27.6%, 42.8%, p = 0.042), Tubal-factor (2.5%, 2.1%, 13.4, p = 0.002) and Ovulation-disorders/PCOS (24%, 32%, 12.5% p = 0.002). Endometriosis trended higher in women with IVF (p = 0.09).

A positive predictor for SC was unexplained infertility(p = 0.0001). A negative predictor was endometriosis(p = 0.005). SC was sub-significantly less likely in the presence of MF (p = 0.057). Unexplained-infertility was a positive predictor for OI±IUI pregnancies(p = 0.047), whereas MF was a negative predictor(p = 0.0001). As for IVF-conceptions, MF was a positive predictor(p = 0.008), while unexplained-infertility negatively predicted conception by IVF(p = 0.018). Ovulation-disorders/PCOS trended lower in women with IVF (p = 0.052). While baseline serum estradiol levels were similar between groups (means 194–218pmol/L), multivariate regression showed it to be a predictor for OI±IUI and IVF conceptions. The clinical significance of this finding is not clear. Interestingly, female age and ovarian reserve were not found to predict one type of conception over another. Other possible predictors in the model were not significant.

Limitations, reasons for caution

This retrospective cohort may hide underlying bias. Clinical pregnancies were evaluated and not live birth. Our cohort represents patients that conceived and do not offer information about the entire sub-fertile population that is treated in our center, which is also a strength as it’s a novel way of evaluating predictors.

Wider implications of the findings: Among patients that conceived spontaneously, advanced age and ovarian reserve did not play a negative role. Predictors of pregnancy were confirmed as expected with the majority of unexplained infertility conceptions occurring spontaneously or with OI+/-IUI, patients with Male factor infertility often conceived by IVF, and ovulation disorders by OI+/-IUI.

Trial registration number

NA

Variations in storm-induced bed level dynamics across intertidal flats

Hydrodynamic forces on intertidal flats vary over a range of temporal and spatial scales. These spatiotemporal inhomogeneities have implications for intertidal flat morphodynamics and ecology. We determine whether storm events are capable of altering the long-term morphological evolution of intertidal flats, and unravel the contributions of tidal flow, wind-driven flow, waves, and water depth on inhomogeneities in bed level dynamics (bed level changes over ~days) across these areas. We complement decades of bed level measurements on eight intertidal flats in two estuaries in the Netherlands with an extensive 1-month field campaign on one of those flats. Across this intertidal flat, the hydrodynamics and morphodynamics of a storm event were captured, including the post-storm recovery. We show that individual events can persistently alter the morphological evolution of intertidal flats; magnitudes of some bed level changes are even comparable to years of continuous evolution. The morphological impacts of events are largely controlled by the relative timing of the forcing processes, and not solely by their magnitudes. Spatiotemporal variations in bed level dynamics of intertidal flats are driven by a combination of: (1) the inhomogeneous distributions of the hydrodynamic forcing processes (including the under-explored role of the wind); and (2) the linear proportionality between bed level dynamics and the local bed slope.

Levels of CEACAM6 in Peripheral Blood Are Elevated in Patients with Plasma Cell Disorders: A Potential New Diagnostic Marker and a New Therapeutic Target?

INTRODUCTION

The prognosis of multiple myeloma is still unfavorable due to inherent characteristics of the disease and the often-delayed diagnosis due to widespread and unspecific symptoms such as back pain and fatigue. Therefore, a simple diagnostic blood test would be helpful to speed up the diagnostic procedure in such patients (pts.). Here, we evaluated the diagnostic value of plasma levels of carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) in the peripheral blood and bone marrow of pts. with plasma cell disorders and in healthy controls.

MATERIALS AND METHODS

Immunoreactive CEACAM6 was determined in the peripheral blood and bone marrow (n = 95/100) of pts. with monoclonal gammopathy of unknown significance (MGUS: 28/37), newly diagnosed multiple myeloma (NDMM: 42/40), and relapsed/refractory multiple myeloma (RRMM: 25/23) by sandwich ELISA.

RESULTS

Median CEACAM6 levels in the peripheral blood of pts. with plasma cell disorders were significantly higher than those of healthy controls (healthy controls: 15.2 pg/ml (12.1-17.1); MGUS: 19.0 pg/ml (16.4-22.5); NDMM: 18.0 pg/ml (13.4-21.2); and RRMM: 18.9 pg/ml (15.2-21.5); p < 0.001). Plasma levels of CEACAM6 discriminated healthy subjects from MGUS/NDMM pts. (AUC = 0.71, 95% CI: 0.6-0.8); i.e., a CEACAM6 level > 17.3 pg/ml has an 82% (95% CI: 70-90) predictive probability for the identification of MGUS or NDMM. Moreover, CEACAM6 levels in the bone marrow were significantly higher in RRMM pts. than in NDMM pts. (p = 0.04), suggesting a role of this molecule in disease progression.

CONCLUSION

CEACAM6 plasma levels can noninvasively identify pts. with a plasma cell disorder and should be evaluated prospectively as a potential diagnostic marker. Moreover, due to high CEACAM6 levels in the bone marrow in RRMM pts., this adhesion molecule might be a therapeutic target in multiple myeloma pts.

Morphohistological analysis and histochemistry of Feijoa sellowiana somatic embryogenesis

Morphohistological analysis and histochemical studies were carried out during the induction and development of Feijoa sellowiana somatic embryos. Zygotic embryos were cultured on LPm medium containing 2,4-dichlorophenoxyacetic acid (20 microM) and glutamine (8 mM). Somatic embryogenesis could be induced from embryogenic cells that originated in meristematic centers or from clusters of cells. The presence of few starch grains and abundant protein bodies was observed in the globular and early torpedo stages, while in torpedo and cotyledonary-stage somatic embryos an enhanced synthesis of starch grains was associated with the accumulation of reserves to be used in the conversion of the embryos to plantlets. Proteins were predominantly observed in protoderm cells, as well as in the meristematic apical region of torpedo and cotyledonary-stage somatic embryos.

Novel HLA-A locus alleles including A*01012, A*0306, A*0308, A*2616, A*2617, A*3009, A*3206, A*3403, A*3602 and A*6604

This paper describes 10 novel HLA-A alleles that have been characterized by DNA sequencing. Seven alleles, A*0308, A*2616, A*3009, A*3206, A*3403, A*3602 and A*6604 carry motifs observed in other HLA-A alleles, suggesting that gene conversion has created this diversity. The remaining three alleles, A*01012, A*0306 and A*2617, contain polymorphisms not previously found in any "classical" class I allele. All alleles were identified due to unexpected probe hybridization patterns during routine SSOP typing. Exons 2 and 3 of each allele were subsequently characterized by DNA sequencing.

Twelve novel HLA-B*15 alleles carrying previously observed sequence motifs are placed into B*15 subgroups

Twelve new B*15 alleles are described. All of the known B*15 alleles are divided into subgroups based on serologic assignments and/or nucleotide sequence polymorphisms. These groups might be used as a reference for DNA-based testing at an intermediate (i.e. "serologic") level of resolution.

DRB3 alleles with variations in the annealing sites of commonly used amplification primers

New HLA alleles are often identified initially from observing uncommon patterns found in low-resolution typing performed via polymerase chain reaction using sequence-specific oligonucleotide probes (PCR-SSOP). Recently, the HLA-DR oligotyping analysis of two Caucasian, one Caucasian/American Indian and two African American individuals resulted in the identification of three novel DRB3 alleles. Using DRB-specific primer sets commonly employed in amplification-based typing, all four individuals were originally characterized as DRB3 negative. Direct sequencing identified DRB3*0104 (variation at codon 8, TCG instead of TTG), and DRB3*0101202 (variation at intron (-13), G instead of C). One individual appeared to carry a DR52-associated DRB1 allele without an associated DRB3 allele. Lack of conservation at the junction of intron 1 and exon 2 of the DRB3 gene suggests that commonly used DRB-specific primer sets may need to be modified.

The relationship between HLA-B45 and B* 5002 in the five major U.S. population groups

The antigen encoded by B*5002 differs in sequence from that encoded by B*5001 only at amino acid residue 167 (consensus tryptophan vs. serine) which results in B45 serologic reactivity. To search for B*5002, the frequencies of alleles encoding the serologically defined B45 antigen were determined by sequence-based typing in 5 major U.S. populations: Caucasians, African Americans, Asians/Pacific Islanders, Hispanics, and Native Americans. The percent of serologically defined B45-positive individuals in the 5 populations ranged from 0.7-9.0%. Thirty-two B45-positive individuals were randomly chosen, when available, for sequence-based typing from each ethnic group from a database of 82,979 consecutively typed unrelated individuals. The B*5002 allele was most prevalent in Hispanic (22%) and Caucasian (9%) individuals, while conspicuously absent in African Americans. In addition, a new allele associated with the B45 antigenic specificity, B*4502, has been identified from an African American individual of Middle Eastern descent. In light of the continuing need to reconcile differences between relationships determined by the sequence homologies among alleles and relationships based on the serologic determinants carried by allelic products when determining the level of HLA match for hematopoietic stem cell transplantation, it is suggested that B*5002 be recognized individually from other B*50 alleles when reporting HLA-B typings for clinical purposes.

Seventeen more novel HLA-A locus alleles

This paper describes seventeen novel HLA-A locus alleles: A*0106, *0235, *0236, *0237, *1105, *2302, *2303, *24032, *2422, *2424, *2503, *2613, *3007, *3203, *3204, *6809 and *6810. All alleles were identified due to unexpected probe reaction patterns during routine SSOP typing. Exons 2 and 3 of these alleles were subsequently characterized by DNA sequencing. The alleles represent a shuffling of sequence motifs, likely by interallelic conversion, expanding the diversity of the HLA system.

Methods of hydration in palliative care patients

A strong and often polarized debate has taken place during recent years concerning the consequences of dehydration in the terminally ill patient. When a patient has a severely restricted oral intake or is found to be dehydrated, the decision to administer fluids should be individualized and made on the basis of a careful assessment that considers problems related to dehydration, potential risks and benefits of fluid replacement, and patients' and families' wishes. This review discusses the assessment of hydration status in the terminal cancer patient and the options for fluid administration in the cases where evaluation of the patients' condition has led to this indication. These include different modes of hypodermoclysis, intravenous hydration, use of the nasogastric route, and proctoclysis. Arguments for and against rehydration have been previously addressed by other authors and fall outside the scope of this review.

Novel HLA-A and HLA-B alleles

Nine novel HLA-A and HLA-B alleles are described: A*2609, A*6803, A*6806, B*1539, B*1540, B*2712, B*4103, B*5109, and B*5603. Most appear to have arisen by gene conversion events. B*5603 appears to have arisen by a reciprocal recombination event joining exon 2 of a B*55/ *56 allele with exon 3 of a B*15 allele. Serologically, the antigen encoded by this allele types with broad B22- and Bw6-specific alloantisera. Also unique, the antigen encoded by B*2712 does not react with B27-specific alloantisera but does react with Bw6-specific alloantisera.

Clarification of HLA-B serologically ambiguous types by automated DNA sequencing

Assignment of HLA-B types can be hampered by ambiguous reactivity of the typing sera resulting in inaccurate HLA-B assignments. In this study, 19 Korean samples exhibiting ambiguous serologic reactivities were characterized by DNA sequencing. Alleles identified from 7 samples were previously undetected in this population (B*1517, B*4101, B*4701, B*5001, and B*5106) and from 9 samples were common alleles in this population (B*4002, B*4003, B*4006, B*1501, B*1401, B*67012, and B*5401). Three samples were putative HLA-B homozygotes. Three major factors causing serologic ambiguity were identified: weak or false negative reactivity of typing sera (52.4%); cross or false positive reactivity of the sera (38.1%); and absence of information on the reaction patterns due to the lack of appropriate sera in the typing kit (e.g. B*4101 encoded molecule) or to the presence of recently characterized molecules (e.g. B*5106 encoded molecule) (9.5%). Overall, sequencing was helpful in clarifying ambiguous serologic reaction patterns improving the HLA typing for the Korean population.

Sequence of an HLA-B56 variant (B*5604) identified in the Korean population

Three alleles encoding molecules with the B56 serologic specificity have been reported thus far. This study characterized an additional allele encoding a B56 molecule from two unrelated Korean individuals. The novel allele, B*5604, differs from B*5602 by a single nucleotide substitution at codon 103 (CTG-->GTG) resulting in an amino acid change from leucine to valine. The putative haplotype associated with the novel allele was A2-B*5604-Bw6-Cw7-DRB1*15-DRB5*02-DQA1*01-DQB 1*05.

Characterization of an HLA-B62 variant (B*1538) exhibiting an additional B52 serologic reactivity

Antigens bearing the B62 serologic specificity are a heterogeneous group being encoded by at least 10 alleles and are widespread in most populations including the Korean population (10.5%). This study characterized a new allele encoding a B62 molecule with extra B52 serologic reactivity from a Korean family and unrelated individuals. Based on the DNA sequence, it appears that the single nucleotide substitution at codon 171 (TAC-->CAC), resulting in an amino acid change from tyrosine to histidine, is responsible for creating the extra reactivity. B*1538 was confirmed by PCR-SSP using a primer annealing to codon 171 in two additional unrelated individuals also exhibiting the same serologic reaction pattern. The haplotype associated with the novel allele, A31-B*1538-Bw6-Cw3-DRB1*1101-DRB3*02-DQB1*0301, was identified in the family members and two unrelated individuals. The novel B*1538 allele and its associated haplotype adds to the HLA diversity in this population.

Analysis of HLA-A and -B serologic typing of bone marrow registry donors using polymerase chain reaction with sequence-specific oligonucleotide probes and DNA sequencing

Unrelated volunteer donors (69) recruited by the National Marrow Donor Program were HLA typed by DNA-based methods for both the HLA-A and -B loci. Each donor had been previously typed by serology by at least two independent laboratories. Of the 69 samples, all serologic laboratories were in concordance for HLA-A in 62 typed samples and for HLA-B in 48 typed samples. Of the serologically concordant samples, 5 samples typed for HLA-A and 7 samples typed for HLA-B received DNA and serology types differing in their level of resolution. One sample typed for HLA-A and 3 samples typed for HLA-B by DNA methods gave different results from their serologic assignments. Of the samples exhibiting disparities among the different serologic typing laboratories, the DNA-defined types of 7 samples typed for HLA-A and 18 samples typed for HLA-B were consistent with at least one of the serologic assignments. The DNA types for the remaining 3 HLA-B typed samples did not agree with the serologic assignments and their alleles were subsequently sequenced. One of these sequences was a previously undefined allele, B*1537. Sharing of polymorphic sequences among HLA allelic products creates difficulties for consistent serologic assignments of some types complicating the process of identifying potential donors from bone marrow registries. Thus, the use of DNA-based typing techniques for characterization of donor class I types should allow a more consistent definition of types and should speed the donor selection process.

HLA-B alleles associated with the B15 serologically defined antigens

Cells expressing HLA molecules in the B15 family were identified by serologic typing in routine testing of volunteer donors of various ethnic backgrounds for a bone marrow registry. DNA sequencing was used to identify HLA-B15 alleles associated with each serologic type and to examine the diversity within the B15 antigen family. Alleles which appeared predominantly in each B15 serologic cluster included: B15 with no defined serologic subdivision (B*1501), B62 (B*1501), B63 (B*1516, B*1517), B75 (B*1502, B*1521), and B76/77 (B*1513). Other B*15 alleles were also found associated with the serotypes and some of these alleles (e.g., B*1501 and B*1516) were found in two or more serologic clusters illustrating the complexity of this family. The B15 unsplit and B75 groups were the most complex exhibiting 16 and 7 alleles, respectively, within each serotype. Five new B*15 alleles (B*1530, B*1531, B*1533, B*1534, B*1535) and 5 other new HLA-B alleles (B*38022, B*3910, B*4010, B*51012, and B*5108) were also identified.

Visual-field measurements and driving eligibility

BACKGROUND

A 50-year-old black man with an ocular history of open-angle glaucoma was seen for a vision rehabilitation examination, with goals of improving his vision for work and determining his eligibility for driving. He was referred to the clinic through state services for the visually impaired.

METHODS

A low-vision evaluation was performed and baseline information was obtained, including distance- and near-visual acuities, visual fields, and subjective refraction. This information was used to determine if he was eligible for services and if any low-vision devices would benefit him.

RESULTS

The patient demonstrated moderately decreased visual acuity in the right eye (6/15) and very reduced visual acuity in the left eye (6/120). His visual fields varied depending on the test performed, ranging from 85 degrees to 140 degrees horizontal diameter. He was able to remove his spectacles and perform near tasks quite well.

CONCLUSIONS

The patient was counseled that if he used one of the field tests he could qualify for services, but if he chose the other test he would qualify for driving and not qualify for services. The ramifications of using different field tests and understanding their parameters when assessing eligibility for services and benefits can be significant.

Diversity and evolution of the DRB1*03 family: description of DRB1*03022,*0307,*0308

Three previously unreported DRB1*03 alleles are described, adding to the diversity of the DRB1 family of alleles. DRB1*03022 contains a silent substitution at codon 77. DRB1*0307 differs from DRB1*03011 by a substitution at codon 26 resulting in a predicted change from tyrosine to phenylalanine. DRB1*0308 is almost identical to DRB1*03011 differing at codon 58 which specifies the glutamic acid residue commonly found in DRB1*11 alleles. The new alleles (DRB1*03022,*0307,*0308) may have arisen by gene conversion-like events and add to the increasing complexity of the HLA system.

Novel HLA-B alleles, B*8201, B*3515 and B*5106, add to the complexity of serologic identification of HLA types

Three class I alleles, B*8201, B*3515 and B*5106, have been described using DNA and cDNA sequencing. The B*8201 allele is most structurally related to B*5602, differing from it by 14 nucleotide substitutions resulting in 5 amino acid differences. The other two alleles, B*3515 and B*5106, differ from their most closely related HLA-B alleles by 2-3 nucleotide substitutions resulting in 1-2 amino acid substitutions, respectively. The majority of nucleotide substitutions marking these new alleles are observed in other HLA-B alleles suggesting that gene conversion and/or reciprocal recombination have created this diversity. All of the amino acid substitutions are predicted to alter the antigen binding site of the HLA-B molecule. The newly defined HLA-B allelic products were originally defined by their unusual serologic reactivity patterns. The B*8201 allelic product is serologically typed as a B "blank" or as a variant of B22 or B45. These patterns and the serologic reactivity of the other newly described allelic products are consistent with the protein sequence homology among specific HLA-B molecules. While serology remains a powerful tool for detecting HLA diversity, alleles generated by events resulting in the sharing of HLA sequence polymorphisms among alleles at a locus will continue to create complexity in the interpretation of typing results.

Cellular crossreactivity. Implications for solid organ transplantation matching

This study evaluates the cellular crossreactivity among DR11, DR13, and DR8 molecules using TLC reagents generated in reciprocal priming combinations where the responder and stimulator cells express different microvariants of DR11. The large majority of T lymphocyte clones (TLC) derived from such stimulation detect not only the product of the specific DR11 allele expressed by the stimulator but also detect subsets of DR molecules that span serologic specificities. Thus, TLC generated in response to DR(alpha,beta1*1102) detect DR(alpha,beta1*1103) and products of specific DR13, DR8, DR2 and DR4 alleles. Whereas, TLC generated in response to DR(alpha,beta1*1104) detect DR(alpha,beta1*1101), DR(alpha,beta1*1103), and products encoded by specific DR8 and DR2 but not DR13 or DR4 alleles. Since DR11 microvariants cannot be identified serologically, this type of mismatch certainly occurs frequently between DR11 serologically matched donors and recipients. Particularly affected are populations, such as the African American population, that exhibit extensive HLA diversity and exhibit different frequencies of HLA alleles compared with those of the majority of serologically matched cadaveric donors. Rapid methods of DNA-based HLA typing now makes it feasible to utilize this methodology for allele level identificaiton of recipient and donor alleles. Based on the strength of the alloproliferative responses and on the recognition patterns of the TLC reported here, we suggest that retransplant patients might benefit by excluding subsequent donors expressing DR molecules that in vitro demonstrate strong cellular crossreactivity with DR molecules expressed by the previous donor(s) as well as those DR molecules shared with the previous donor(s). Since such a matching schema has the potential to improve retransplant allograft survival, particularly in patients from minority population groups, it should be evaluated clinically.

Novel alleles HLA-B*7802 and B*51022: evidence for convergency in the HLA-B5 family

We have characterized two novel HLA-B alleles, B*7802 and B*51022. The Caucasian-derived variant B*7802 most resembles the African-derived variant B*7801, from which B*7802 differs by two nucleotides. Only one of these modifications, however, is translated: a tyrosine for aspartate substitution occurs at residue 74 in B*7802, while the second nucleotide difference reflects a proximal synonymous substitution in codon 23. A second variant, B*51022, differs synonymously only at codon 23 from B*51021. Comparative analysis of the B5 CREG demonstrates that other pairs of B5 alleles differ synonymously only at codon 23 or synonymously at codon 23 and non-synonymously at a second more distal location. Contrary to the genesis of like pairs of B5 alleles via introduction of coordinate yet distant mutagenic events onto a single B5 progenitor, we postulate that synonymously different B5 progenitor molecules, B5ATT and B5ATC, are evolving in convergence to generate homologous B5 allele pairs differing silently at codon 23. Our finding that B*7802 is a single amino acid away from complete convergence with B*7801 and that B*51022 and B*51021 are in complete convergence is exemplary of such evolution.

Differences in peptide binding of DR11 and DR13 microvariants demonstrate the power of minor variation in generating DR functional diversity

The influence of subtle HLA diversification on antigen binding was explored using murine L-cell transfectants expressing alleles in the DR11/DR13 family and a panel of peptides. The levels of binding among this family of DR microvariants were as diverse as the levels of binding among distantly related DR molecules. Even a single amino acid difference between allelic products had a profound effect on peptide binding. Specific amino acid substitutions, generated using site-directed mutagenesis to alter polymorphic residues at DR beta 32, 37, 57, 58, 67, 71, 86, demonstrated that a specific change within the context of a single DR molecule differed in its effect on the binding of specific peptides. In addition, a specific amino acid substitution had a differential effect on the binding level of a peptide to different DR molecules. Each polymorphic amino acid appeared to play a role in the binding of some peptide. Studies using the amino-terminal portion of the invariant chain CLIP peptide suggested that this peptide may offer varying degrees of competition in the binding of the cellular peptide pool in cells expressing different DR molecules. Finally, the results obtained with two strain-specific peptides from an immunodominant region of a malarial parasite show differential binding to two DR13 molecules, suggesting that immune pressure may promote parasite diversity. A dynamic interaction may exist between pathogens and the immune system shaping the HLA profile in a population. Thus even subtle diversification of the HLA molecules, possibly pathogen driven, can have a substantial effect on peptide binding and immune recognition.

A description of a new DR allele, DRB1*1113

We have discovered a previously unpublished HLA-DRB1 allele, observed in a patient (SB), his mother, and one sibling. The undefined allele gave sporadic positive reactions with sera in the DR52-associated group. SSOPH analysis utilizing both generic and group specific primers and probes also gave ambiguous results. SB typed clearly as a DRB1*0301 (paternal allele) but the DNA from SB also bound probes specific for DRB1*14 and DRB1*11. Sequencing revealed that the undefined allele was similar to a DRB1*14 allele with a segment of sequence found in DRB1*11 alleles. The patient was MLC reactive with donors who express DRB1*0301, *1401 and *0301, *11 and was nonreactive solely to DRB1*0301 (Dw3) homozygous typing cells.

[Predictive factors of resistance to treatment of neuropathic pain]

The aim of this retrospective study was to examine factors related to symptomatic pain treatment in 992 hospitalized patients referred to the pain clinic. These patients accounted for 1440 different pains (1.5 pains/patient), of nociceptive (59%), or neuropathic (24%) origin, a combination of both (16%) and of unidentified (1%) origin. Patients resistant to therapy did not differ from nonresistant patients (62%) in terms of age, sex, or number of pains. Although recommended pharmacological treatments were pursued, the neuropathic origin of pain was a factor in resistance to treatment. Among the neuropathic pains resistant to treatment (42%) a central nervous origin is more frequently found. Resistance to pain was more frequently encountered after strokes, primitive tumor of the central nervous system or traumatic plexopathy, whereas peripheral lesions of the nervous system were more easily controlled by symptomatic treatment. This study shows that central neuropathic pain is more frequently associated with resistance to recommended pharmacological symptomatic treatments. This observation underlines the limits of conventional medical therapy.

[Reproduction data in breeding mares, diseases and losses among suckling foals and preventive husbandry in German stud farms]

By means of a survey, the reproductive rate of mares and the foal losses in ten Thoroughbred, Saddlebred and Pony studs in Germany, mainly from North-Rhine-Westfalia, were collected and evaluated. Data for the survey were recorded for 1985-1990. The study also examined the hygienic management in the surveyed studs, and the morbidity rate of suckling foals was obtained for 1990. In addition to the survey questionnaire each stud was visited once. Two studs of each horse group were visited several times every week from March to August in order to evaluate as exactly as possible the husbandry and morbidity of the suckling foals. The main results were: The abortion rate in Thoroughbred and Saddlebred horses was about 4.5%, of the Ponies 1%. After the 299th day of gestation, fetal mortality ranged from 3.2 to 3.5%. In the more intensively observed studs 33% of Thoroughbred foals, 42% of Saddlebred foals and 11% of Pony foals became ill. Saddlebred foals were more frequently affected by respiratory disease while Thoroughbred and Pony foals were mainly afflicted by diarrhea. The scope of husbandry measures was broader and more intensive in the Thoroughbred and Pony studs compared to the Saddlebred studs.

Nonrandom T cell receptor usage in the allorecognition of HLA-DR1 microvariation

Microvariation within the DR1 Ag family has created two DR molecules which differ only at beta-chain residues 85 (Val/Ala) and 86 (Gly/Val). TCR utilized by human alloproliferative T lymphocyte clones which can distinguish between these microvariants have been characterized by cDNA sequencing. The alpha- and beta-chain cDNA utilize a diverse set of variable (V) gene segments although the same V segment may be used by different individuals suggesting that V segment usage by the alloreactive T lymphocyte clones is nonrandom. There appears to be no difference in the repertoire of V segments utilized by T lymphocytes that preferentially recognize specific DR1 allelic products (DR(alpha,beta 1*0101) or DR(alpha,beta 1*0102)) and T lymphocytes that recognize both DR1 molecules. In contrast, the junctional regions of both alpha- and beta-chains are diverse in length and sequence although some common elements can be observed among TCR which share V gene segments. Two TCR which share V alpha and V beta gene segments differ in fine specificity for specific DR1 allelic products implicating the junctional regions of alpha- and beta-chains in the recognition of differentially bound peptides and/or in recognition of DR beta-chain residues 85 and 86. The stimulation of many diverse TCR by the limited allelic variation between DR(alpha,beta 1*0101) and DR(alpha,beta 1*0102) molecules suggests that the effect of DR microvariation on human immune responsiveness may be substantial.

Nonrandom T cell receptor usage in the allorecognition of HLA-DR1 microvariation

Microvariation within the DR1 Ag family has created two DR molecules which differ only at beta-chain residues 85 (Val/Ala) and 86 (Gly/Val). TCR utilized by human alloproliferative T lymphocyte clones which can distinguish between these microvariants have been characterized by cDNA sequencing. The alpha- and beta-chain cDNA utilize a diverse set of variable (V) gene segments although the same V segment may be used by different individuals suggesting that V segment usage by the alloreactive T lymphocyte clones is nonrandom. There appears to be no difference in the repertoire of V segments utilized by T lymphocytes that preferentially recognize specific DR1 allelic products (DR(alpha,beta 1*0101) or DR(alpha,beta 1*0102)) and T lymphocytes that recognize both DR1 molecules. In contrast, the junctional regions of both alpha- and beta-chains are diverse in length and sequence although some common elements can be observed among TCR which share V gene segments. Two TCR which share V alpha and V beta gene segments differ in fine specificity for specific DR1 allelic products implicating the junctional regions of alpha- and beta-chains in the recognition of differentially bound peptides and/or in recognition of DR beta-chain residues 85 and 86. The stimulation of many diverse TCR by the limited allelic variation between DR(alpha,beta 1*0101) and DR(alpha,beta 1*0102) molecules suggests that the effect of DR microvariation on human immune responsiveness may be substantial.

[Epidemiological and virological research on influenza and viral respiratory infections in the southeastern region of Romania in the cold season of 1991-1992]

Investigations pointed out the high level of respiratory diseases and pneumonias in children, especially in the youngest ones (0-1 year-old) during all the surveyed period. An influenza outbreak during the second half of February was registered in the infantile population--school and low-age children--which gave most of the cases. Serology and isolations incriminated an influenza virus related to the A/Beijing 353/89 (H3N2) strain. Isolations worked out after the influenza epidemics pointed out circulation of parainfluenza and adenoviruses. The necessity is emphasized of the anti-influenza vaccination of low-age children.

[Complex studies of virology, microbiology, biochemistry and epidemiology in the adults of a semi-closed community vaccinated against influenza with the inactivated NIVGRIP vaccine intranasally]

A study was conducted on the specific and non specific immunomodulator effects of the inactivated vaccine NIVGRIP. The results revealed the seroconversion of HAI antibodies against influenza and mumps viruses and the reduction of viral and microbial flora of the pharynx. The kinetics of some proteins specific to the acute stage (siderophiline antitrypsin, microglobulin, complement C1q and C2 factors, C reactive protein and fibronectin) was also investigated and significant quantitative modifications were noticed in vaccinated subjects. The mean illness duration (acute respiratory disease) was three times as short in vaccinated subjects as in controls.

[The possibility of the vertical intrapartum transmission of the HIV and HB viruses]

A study was performed on 756 serum samples collected from the umbilical cord of newborn infants. HBV markers were found in 4.63% of the tested subjects. Of these samples, 291 were tested for the HIV markers and 0.34% were found positive (versus 0 in the controls, most of them men from the same region). Results confirmed the possibility of vertical transmission of both viruses, HBV and HIV, in Romania.

[The incidence of viral and microbial antigens and the serum interferon titer in certain forms of rheumatism]

The presence of some viral and inframicrobial antigens in peripheral leukocytes was investigated by the indirect immunofluorescence technique in 120 patients with different forms of rheumatism and 50 clinically healthy controls. Mycoplasma pneumoniae and type 3 para-influenza virus were detected most frequently. The determination of serum interferon titer revealed a rise of this product in rheumatic patients.

[The virological study of a certified focus of acute respiratory diseases in a half-closed community]

An acute respiratory disease outbreak appeared during February and March 1988 in a half-closed community. Virologic investigations were conducted and an influenza virus type B strain was isolated, antigenically like B/Victoria 2/87. Administration of the anti-influenza vaccine in the fifth day of the outbreak evolution led to considerable reduction of the new cases and to outbreak extinction after 48 hours.

DQ polymorphism: an analysis of DQw4 alpha and beta membrane proximal regions

The complete coding sequences of cDNA clones encoding the DQw4 alpha and beta polypeptides have been determined from two individuals expressing the DRw18(3), DQw4 haplotype. Although the first domain nucleotide sequence of the DQ alpha cDNA is very similar to the DQw2 alpha sequence, the sequence of the membrane proximal region (encoding second domain, transmembrane, and cytoplasmic segments) is more similar to DQw3-like alpha-gene sequences. The nucleotide sequence of the membrane proximal region of the DQw4 beta gene is identical to the DQw8 sequence in contrast to the extensive differences in the region encoding the first domains of these polypeptides. These sequences have been used to determine the evolutionary relationships among DQ alpha and beta genes.

The DR3(w18),DQw4 haplotype differs from DR3(w17),DQw2 haplotypes at multiple class II loci

The polymorphism of HLA class II molecules in man is particularly evident when comparisons between population groups are made. This study describes a DR3 haplotype commonly present in the American black population. Unlike the Northern European population, in which almost all DR3 individuals are DQw2, approximately 50% of DR3-positive American blacks express a DQw4 allelic product. This study characterizes the DR subregion of that haplotype. cDNA sequence analysis has revealed a DR beta gene which differs at several positions from previously described DR3 beta 1 genes. It is postulated that a gene-conversion-like event with a DRw52 beta gene as donor has generated some of these differences. The haplotype carries a DRw52a allele as defined by oligonucleotide hybridization studies. DNA restriction fragment analysis using a family and several unrelated individuals has allowed us to identify DR alpha and beta fragments associated with the DR3(w18),DQw4 haplotype. The most striking observation is that the DR3(w18),DQw4 haplotype differs from DR3(w17),DQw2 haplotypes at multiple class II loci. Several genetic mechanisms including reciprocal recombination, gene conversion, and point mutation were involved in generating the differences between these haplotypes. Once established, the DR3(w18),DQw4 haplotype appears to be relatively stable in the population.