Kikuchi syndrome, Hashimoto thyroiditis and lupus serology. Apropos of a case

Histiocytic necrotizing lymphadenitis (Kikuchi's disease) is an uncommon disease of the cervical lymph nodes occurring in young women, commonly associated with various auto-immune or infectious diseases. We describe the case of a 17 year-old girl who presented a Kikuchi's lymphadenitis occurring concomitantly with Hashimoto's thyroiditis and lupus serology as anti-nuclear, anti-DNA, anticardiolipid antibodies and hypocomplementemia. The patient was treated with prednisone and hydroxychloroquine. Thirty months after, she is doing well and hydroxychloroquine is continued.     

Evolution of MHC genetic diversity: a tale of incest, pestilence and sexual preference

Evidence from the house mouse (Mus) suggests that the extreme diversity of genes of the major histocompatibility complex (MHC) results from three different forms of selection involving infectious disease (pestilence), inbreeding (incest) and MHC-based mating (sexual) preferences. MHC-based disassortative mating preferences are presumed to have evolved because they reduce homozygosity throughout the genome, and particularly within loci linked to the MHC. Progeny derived from such disassortative matings would enjoy increased fitness because of both reduced levels of inbreeding depression and increased resistance to infectious disease arising from their increased MHC heterozygosity.     

Comparison of various Helicobacter pylori detection methods: serology, histology and bacteriology

A total of 3,184 paediatric patients with sporadic pharyngitis was studied at King Khalid University Hospital in Riyadh, Saudi Arabia. In addition, 478 children without pharyngitis who were matched for age and sex were included as controls. Group A beta-haemolytic streptococci (beta HS) were detected significantly more often among the children with pharyngitis than among the controls (8.4% vs 2.3%; p < 0.0001). In contrast, total non-group A and group C beta HS were isolated at lower frequency from the sick than control children (0.9% vs 2.5% and 0.2% vs 1.2% respectively; p < 0.01) while other non-group A beta HS such as groups B, G and F were each isolated in similar frequency from both the sick and control children. We conclude that non-group A beta HS appear not to be as important as aetiological agents of sporadic pharyngitis in these children.     

RT1-U: identification of a novel, active, class Ib alloantigen of the rat MHC

In common with other mammalian species, the laboratory rat (Rattus norvegicus) expresses MHC class I molecules that have been categorized as either classical (class Ia) or nonclassical (class Ib). This distinction separates the class Ia molecules that play a conventional role in peptide Ag presentation to CD8 T cells from the others, whose function is unconventional or undefined. The class Ia molecules are encoded by the RT1-A region of the rat MHC, while the RT1-C/E/M region encodes up to 60 other class I genes or gene fragments, a number of which are known to be expressed (or to be expressible). Here we report upon novel MHC class Ib genes of the rat that we have expression cloned using new monoclonal alloantibodies and which we term RT1-U. The products detected by these Abs were readily identifiable by two-dimensional analysis of immunoprecipitates and were shown to be distinct from the class Ia products. Cellular studies of these molecules indicate that they function efficiently as targets for cytotoxic killing by appropriately raised polyclonal alloreactive CTL populations. The sequences of these class Ib genes group together in phylogenetic analysis, suggesting a unique locus or family. The combined serological, CTL, and sequence data all indicate that these products are genetically polymorphic.     

Peptide-induced T cell clones: specificity, MHC restriction, proliferation and cytokine pattern as a function of different stimulations

CD4+ T cell clones were generated to tetanus toxin or to two tetanus toxin-derived peptides p2 (AA 830-834) and p30 (AA 947-976). 11 of the 24 p30-specific clones reacted to shorter p30 subunits (p301 or p302), and only 14 of the p2 or p30-specific clones reacted with TT presented by EBV-transformed B cell lines (B-LCL). The p30-specific clones were HLA-DP4 restricted. In contrast to autologous B cell lines, the majority of allogeneic, but HLA-DP4-positive cell lines failed to present p30 to the specific clones. We concluded that T cell clones are highly specific and that both, small alterations of the peptide length as well as discrete differences of the HLA-molecule may abrogate recognition of the peptide HLA complex by T cells. Moreover, use of peptides as stimulators of T cells may recruit and activate T cells which fail the "original" peptide, derived from normal antigen processing. Clones could usually be maintained in culture for 4-6 months, but with the help of freezing and thawing some clones are now available for over 2 years and still specific. Comparison of different autologous antigen-presenting cells, namely B-LCL and activated MHC class II-positive T cells revealed that not all clones were able to mount a proliferative response to peptide presentation by T cells, while all clones proliferated to B cells as APC. If stimulated with peptide and B-LCL, the clone proliferating to T cells as APC (so-called T responder clones) secreted a broad spectrum of cytokines (Th0-like) and were easier to maintain in culture. In contrast, clones which were unable to proliferate to peptide presentation, so-called T-nonresponder clones, showed a more restricted cytokine pattern and elevated or very low IL4/IFN gamma ratio upon antigen specific stimulation. However, all clones secreted at least small amounts of IL2, IL4, IFN gamma and TNF alpha, if stimulated by PMA and ionomycin. Thus, both chemical and antigen-specific stimulations should be considered if T cell clones are classified as Th1 or Th2, whereby those clones, which secrete a limited cytokine pattern after antigen stimulation only, might be named Th1 or Th2 like clones, while clones which even after PMA/ionomycin do not secrete all cytokines, might represent "real" Th1 or Th2 clones.     

The orientation of a T cell receptor to its MHC class II:peptide ligands

The TCR found on CD4 T cells recognizes peptides bound to self MHC class II molecules as well as non-self MHC class II molecules. We have used the receptor on a cloned T cell line called D10.G4.1 (D10) to perform a structure-function analysis of this interaction. The D10 T cell clone recognizes not only a peptide from conalbumin (CA-wt) bound to syngeneic I-Ak against which it was raised, but also the allogeneic MHC molecules I-A(b,v,p,q,d). In the present study, we show that residue 30 in complementarity-determining region 1 (CDR1) of the TCR alpha-chain interacts with the I-A alpha-chain at hvr2 (residues 52, 53, and 55). We also show that residue 51 in CDR2 of the TCR alpha-chain interacts with the peptide at peptide residue 2. Finally, we show that residue 29 in CDR1 of the TCR beta-chain affects recognition of the glutamic acid at residue 66 in the I-A beta-chain. These data suggest an orientation of TCR relative to its peptide:MHC class II ligands. We argue that this orientation will be shared by all CD4 TCRs, and that it is only subtly different from the common orientation proposed for receptors binding to MHC class I.     

Anti-HCV serology for screening, diagnosis and surveillance of hepatitis C: role of the immunoblot

Smoking is a major health hazard. Most cigarette smokers start by the age of 18 years. The purpose of this study was to assess the prevalence of the intention to smoke among the students of a metropolitan compared to a non-metropolitan high school. The influence of age, sex, demographic and socio-economic variables, and the role of smoking models of family members and friends, were examined. Nine hundred forty-five students (529 males and 416 females; mean age 15.8 +/- 1.5 years) attending a high school in Naples and 442 students (223 males and 219 females; mean age 16.1 +/- 1.6 years) in Capua, a small town 40 Km distant from Naples, filled in an extensive questionnaire on smoking. The prevalence of intention to smoke was 10.4% in Naples and 9.3% in Capua. It was related to age (p < 0.01) in Naples, but not in Capua. The prevalence of smokers was 24.2% in Naples (males 21.6%, females 27.6%; p = 0.038) and 24.1% in Capua (males 29.2%, females 19%; p = 0.017). As expected, in both cities intention to smoke was associated (p < 0.001) with the strength of existing smoking habit. Students smoking over 21 cigarettes/week were more likely to continue than students smoking less 21 cigarettes/week, both in Naples and in Capua. More than half of smoking students, in both cities, were irresolute about their habit in the subsequent year. In Naples, intention to smoke of male students was associated with mother's (p = 0.02) and siblings' (p < 0.0001) smoking habit; in female students intention to smoke was associated with father's (p = 0.02), mother's (p < 0.001), parents' (p < 0.01) and siblings' smoking habit (p = 0.0002). In Capua an association was evident, in male students, between intention to smoke and paternal smoking habit (p = 0.04); in female students, intention to smoke was associated with siblings' smoking habit (p = 0.03). In Naples and in Capua, for both sexes, intention to smoke was related to smoking habits of the best friend of the same sex (p < 0.0005), the best friend of the opposite sex (p < 0.00005) and friends (p < 0.00001). Multivariate analysis showed, in Naples, an independent relation between adolescent intention to smoke and age (p = 0.01), smoking status of student (p < 0.0001) and friends' smoking habit (p = 0.01). In male students intention to smoke was associated with age (p = 0.003), smoking habit of student (p < 0.0001), mother's (p = 0.02) and friends' (p = 0.02), whereas in females it was associated with smoking behavior of student (p < 0.0001). In Capua student intention to smoke was related to the smoking status of the student (p < 0.0001) and of the best friend of the opposite sex (p < 0.04); in male as in female students, intention to smoke was associated with smoking habit of the student (p < 0.0001). In conclusion, prevalence of adolescents' intention to smoke is similar in two distinct populations of high school students of a city and a small town. Smoking is at higher prevalence among females in the city and among males in the small town. Intention to smoke increases with age, in the great city, and is related to student's existing habit and peer models. More than half of smoking students, in both cities, were irresolute about their habit in the subsequent year. This study has identified some variables associated with adolescents' intention to smoke; we feel that these findings may contribute to a better understanding of smoking behavior among adolescents and may have preventive implications.     

Autoimmune diabetes: the role of T cells, MHC molecules and autoantigens

Type 1 diabetes (IDDM) is a T cell mediated autoimmune disease which in part is determined genetically by its association with major histocompatibility complex (MHC) class II alleles. The major role of MHC molecules is the regulation of immune responses through the presentation of peptide epitopes of processed protein antigens to the immune system. Recently it has been demonstrated that MHC molecules associated with autoimmune diseases preferentially present peptides of other endogenous MHC proteins, that often mimic autoantigen-derived peptides. Hence, these MHC-derived peptides might represent potential targets for autoreactive T cells. It has consistently been shown that humoral autoimmunity to insulin predominantly occurs in early childhood. The cellular immune response to insulin is relatively low in the peripheral blood of patients with IDDM. Studies in NOD mice however have shown, that lymphocytes isolated from pancreatic islet infiltrates display a high reactivity to insulin and in particular to an insulin peptide B 9-23. Furthermore we have evidence that cellular autoimmunity to insulin is higher in young pre-diabetic individuals, whereas cellular reactivity to other autoantigens is equally distributed in younger and older subjects. This implicates that insulin, in human childhood IDDM and animal autoimmune diabetes, acts as an important early antigen which may target the autoimmune response to pancreatic beta cells. Moreover, we observed that in the vast majority of newly diagnosed diabetic patients or individuals at risk for IDDM, T cell reactivity to various autoantigens occurs simultaneously. In contrast, cellular reactivity to a single autoantigen is found with equal frequency in (pre)-type 1 diabetic individuals as well as in control subjects. Therefore the autoimmune response in the inductive phase of IDDM may be targeted to pancreatic islets by the cellular and humoral reactivity to one beta-cell specific autoantigen, but spreading to a set of different antigens may be a prerequisite for progression to destructive insulitis and clinical disease. Due to mimic epitopes shared by autoantigen(s), autologous MHC molecules and environmental antigens autoimmunity may spread, intramolecularly and intermolecularly and amplify upon repeated reexposure to mimic epitopes of environmental triggers.     

The prevalence of campylobacters and arcobacters in broiler chickens

Chicken carcasses from a supermarket and from a poultry abattoir were examined using methods designed to isolate as many strains of campylobacters and related organisms as possible. Strains of arcobacter, but no campylobacters, were isolated from every carcass after enrichment. Campylobacter jejuni subsp. jejuni was isolated from all carcasses examined by direct plating and other Campylobacter-like strains were isolated from nine out of 15 abattoir carcasses by direct plating but not after enrichment. Only the Camp. jejuni subsp. jejuni strains could be identified to species level using a readily available identification scheme and/or a commercial identification kit. Examination of caecal contents from the 15 abattoir poultry yielded Camp. jejuni subsp. jejuni and Campylobacter-like strains from 15 and eight by direct plating, and from six and nine after enrichment, respectively. Four sites in the intestine of the abattoir birds (60 samples) were examined for arcobacters and only one strain was isolated. This indicates that arcobacters are probably not normal inhabitants of the poultry intestine. Poultry is a rich source of other campylobacteria besides the thermophilic Campylobacter spp.     

The comparative amino acid sequences, substrate specificities and gene or cDNA nucleotide sequences of some prokaryote and eukaryote amidinotransferases: implications for evolution

The amino acid sequences of the amidinotransferases and the nucleotide sequences of their genes or cDNA from four Streptomyces species (seven genes) and from the kidneys of rat, pig, human and human pancreas were compared. The overall amino acid and nucleotide sequences of the prokaryotes and eukaryotes were very similar and further, three regions were identified that were highly identical. Evidence is presented that there is virtually zero chance that the overall and high identity regions of the amino acid sequence similarities and the overall nucleotide sequence similarities between Streptomyces and mammals represent random match. Both rat and lamprey amidinotransferases were able to use inosamine phosphate, the amidine group acceptor of Streptomyces. We have concluded that the structure and function of the amidinotransferases and their genes has been highly conserved through evolution from prokaryotes to eukaryotes. The evolution has occurred with: (1) a high degree of retention of nucleotide and amino acid sequences; (2) a high degree of retention of the primitive Streptomyces guanine + cytosine (G + C) third codon position composition in certain high identity regions of the eukaryote cDNA; (3) a decrease in the specificities for the amidine group acceptors; and (4) most of the mutations silent in the regions suggested to code for active sites in the enzymes.     

The nucleotide sequences of 5S rRNAs from a rotifer, Brachionus plicatilis, and two nematodes, Rhabditis tokai and Caenorhabditis elegans

The nucleotide sequences of 5S rRNAs from a rotifer, Brachionus plicatilis, and two nematodes, Rhabditis tokai and Caenorhabditis elegans have been determined. The rotifer has two 5S rRNA species that are composed of 120 and 121 nucleotides, respectively. The sequences of these two 5S rRNAs are the same except that the latter has an additional base at its 3'-terminus. The 5S rRNAs from the two nematode species are both 119 nucleotides long. The sequence similarity percents are 79% (Brachionus/Rhabditis), 80% (Brachionus/Caenorhabditis), and 95% (Rhabditis/Caenorhabditis) among these three species. Brachionus revealed the highest similarity to Lingula (89%), but not to the nematodes (79%).     

General paralysis of the insane and AIDS in old age psychiatry: epidemiology, clinical diagnosis, serology and ethics--the way forward

While the incidence of general paralysis of the insane (GPI) has declined, AIDS (acquired immune deficiency syndrome) has emerged as a new illness. Today, in England and Wales, as many elderly people die from AIDS as from neurosyphilis, although both diagnoses are rare in this age group. Both are serious medical conditions with psychiatric manifestations. For both, serological tests may identify the disease, and treatment may be of benefit, but there is considerable social stigma attached to the diagnoses. Ethical guidelines for serological testing for HIV (human immunodeficiency virus) have been available for over a decade. In view of the similarities between the diseases, it may be unethical to test patients for syphilis routinely. Epidemiology, risk factors, neurological and neuropsychiatric features and ethics must be considered before testing for both syphilis and HIV.     

The tetraspan protein CD82 is a resident of MHC class II compartments where it associates with HLA-DR, -DM, and -DO molecules

In specialized APCs, MHC class II molecules are synthesized in the endoplasmic reticulum and transported through the Golgi apparatus to organelles of the endocytic pathway collectively called MHC class II compartments (MIICs). There, the class II-associated invariant chain is degraded, and peptides derived from internalized Ag bind to empty class II in a reaction that is facilitated by the class II-like molecule HLA-DM. An mAb raised to highly purified, immunoisolated MIICs from human B lymphoblastoid cells recognized CD82, a member of the tetraspan family of integral membrane proteins. Subcellular fractionation, immunofluorescence microscopy, and immunoelectron microscopy showed that CD82 is highly enriched in MIICs, particularly in their internal membranes. Coprecipitation analysis showed that CD82 associates in MIICs with class II, DM, and HLA-DO (an inhibitor of peptide loading that binds DM). Similar experiments showed CD63, another tetraspan protein found in MIICs, also associates with these molecules in the compartment and that CD82 and CD63 associate with each other. Preclearing experiments demonstrated that both CD82 and CD63 form complexes with DM-associated class II and DM-associated DO. The ability of CD82 and CD63 to form complexes with class II, DM, and DO in MIICs suggests that the tetraspan proteins may play an important role in the late stages of MHC class II maturation.     

The orientation and nature of the interaction between beef insulin-specific TCRs and the insulin/class II MHC complex

Recent crystallographic studies suggest that TCR interact with peptide/class I MHC complexes in a single preferred orientation. Although similar studies have not been performed for class II-restricted TCR, it has been proposed that T cell recognition of peptide/class II complexes has similar orientational restrictions. This study represents a functional approach to systematic analysis of this question. Twenty-one mutant A beta(d) molecules were produced by alanine scanning mutagenesis and assessed for their ability to present species variants of insulin to a panel of beef insulin-specific T cell hybridomas with limited TCR alpha- and/or beta-chain sequence differences. We demonstrate that all beef insulin-specific TCR have the same orientation on the insulin/Ad complex, such that the alpha-chain interacts with the carboxyl-terminal region of the A beta(d) alpha-helix, and the beta-chain complementarity-determining region 3 interacts with the carboxyl-terminal portion of the peptide, consistent with that observed for crystallized TCR-peptide/class I complexes. Despite this structural constraint, even TCR that share structural similarity show remarkable heterogeneity in their responses to the panel of MHC mutants. This variability appears to result from conformational changes induced by binding of the TCR to the complex and the exquisite sensitivity of the threshold for T cell activation.