[A case of posterior thyroid ophthalmopathy following neck irradiation]

OBJECTIVE

To report a case of a patient who developed a Graves' ophthalmopathy class III two weeks after receiving radiotherapy in the neck.

CASE HISTORY

He was a male of 51 years of age with a stage IIIB Hodgkin's disease who received chimio- and radio-therapy two weeks previous to the ophthalmopathy. The computed axial tomography showed retroorbital changes. The thyroid function tests, including the stimulation with thyrotropin releasing hormone and the microsomal and thyroglobulin antibodies were normal. The patient was treated with oral prednisone, followed by retroocular radiotherapy on the right eye. The exophthalmos improved and the diplopia disappeared.

Association of primary antiphospholipid syndrome with primary adrenal insufficiency

The association of primary adrenal insufficiency with antiphospholipid antibodies is usually reported in the context of adrenal thrombosis or hemorrhage. We describe a 35-year-old woman who developed a primary antiphospholipid syndrome (spontaneous abortion, thrombocytopenia, and cerebrovascular occlusion) in association with primary adrenal insufficiency without evidence of suprarenal hemorrhage or thrombosis.

Identification and characterization of a new major histocompatibility complex class I gene in carp (Cyprinus carpio L.)

In this study we report the finding of three representatives of a new group of major histocompatibility complex class I sequences in carp: Cyca-12 (Cyca-UA1*01), a full-length cDNA; Cyca-SP1 (Cyca-UAW1), a polymerase chain reaction (PCR) fragment from cDNA; and Cyca-G11 (Cyca-UA1*02), a partial genomic clone. Comparison of the amino acid sequences of Cyca-12, Cyca-SP1, and Cyca-G11 with classical and non-classical class I sequences from other species shows considerable conservation in regions that have been shown to be involved in maintaining the structure and function of class I molecules. The genomic organization of Cyca-12 has been elucidated by analysis of a partial genomic clone (Cyca-G11, in combination with PCR amplifications on genomic DNA of a homozygous individual. Although the genomic organization is similar to that found in class I genes from other species, the 3' untranslated region contains an intron which is unprecedented in class I genes, and intron 2 is exceptionally large (+/-14 kilobases). Southern blot analysis indicates the presence of multiple related sequences. In phylogenetic analyses, the Cyca-UA sequences cluster with class I genes from zebrafish and Atlantic salmon, indicating that the ancestral gene arose before the salmonid/cyprinid split, approximately 120-150 million years ago. The previously reported class I Cyca-Z genes from carp and Caau-Z genes from goldfish cluster as a completely separate lineage. A polyclonal antiserum (anti-Cyca12) was raised against a recombinant fusion protein containing most of the extracellular domains of Cyca-12. The antibodies showed substantial reactivity to the recombinant protein and an Mr 45000 protein in membrane lysates of spleen and muscle, as well as to determinants present on leucocytes in fluorescence-activated cell sorter analyses. Erythrocytes and thrombocytes were found to be negative.

Phylogenetic analysis of cichlid fishes using nuclear DNA markers

The recent explosive adaptive radiation of cichlids in the great lakes of Africa has attracted the attention of both morphologists and molecular biologists. To decipher the phylogenetic relationships among the various taxa within the family Cichlidae is a prerequisite for answering some fundamental questions about the nature of the speciation process. In the present study, we used the random amplification of polymorphic DNA (RAPD) technique to obtain sequence differences between selected cichlid species. We then designed specific primers based on these sequences and used them to amplify template DNA from a large number of species by the polymerase chain reaction (PCR). We sequenced the amplified products and searched the sequences for indels and shared substitutions. We identified a number of such characters at three loci--DXTU1, DXTU2, and DXTU3--and used them for phylogenetic and cladistic analysis of the relationships among the various cichlid groups. Our studies assign an outgroup position to Neotropical cichlids in relation to African cichlids, provide evidence for a sister-group relationship of tilapiines to the haplochromines, group Cyphotilapia frontosa with the lamprologines of Lake Tanganyika, place Astatoreochromis alluaudi to an outgroup position with respect to other haplochromines of Lakes Victoria and Malawi, and provide additional support for the monophyly of the remaining Lake Victoria haplochromines and the Lake Malawi haplochromines. The described approach holds great promise for further resolution of cichlid phylogeny.

Antigenic specificity of lymphocytes isolated from valvular specimens of rheumatic fever patients

T cell lines were established from both valvular specimens and peripheral blood lymphocytes from seven patients with well documented rheumatic heart disease. These cell lines were stimulated with either PHA or streptococcal antigens. Proliferation assays revealed that both valvular and peripheral blood T cell lines reacted to cell wall (CW) and cell membrane (CM) antigens obtained from rheumatic fever associated group A streptococci and not to nephritogenic strains. None of the cell lines reacted to M protein, myosin or other mammalian cytoskeletal proteins. The unique reactivity of rheumatic fever T cell lines only to cellular structures obtained from rheumatogenic strains suggests that these lines react to epitopes specific for antigens obtained from these strains.

Molecular cloning of major histocompatibility complex class II B gene cDNA from the Bengalese finch Lonchura striata

The only avian major histocompatibility complex (Mhc) genes thus far identified are from species of the relatively small order of Galliformes, while by far the largest order of Passeriformes (songbirds), containing some 60% of extant bird species, has not been studied at all in this regard. The Galliformes emerged more than 55 million years (my) ago, the Passeriformes some 25 my ago. Because of the potential for the use of Mhc genes as markers in the study of songbird populations, an attempt was made to clone class II B genes of a passeriform species, the Bengalese finch Lonchura striata acuticauda. Using a set of primers designed on the basis of known sequences, a probe corresponding to part of exon II was obtained by the polymerase chain reaction. The probe was then used to screen a Bengalese finch cDNA library and to isolate and sequence two nearly full-length clones. The sequences reveal the presence of one presumably functional class II B locus in this bird species.

Cloning and characterization of class I Mhc genes of the zebrafish, Brachydanio rerio

The zebrafish (Brachydanio rerio) offers many advantages for immunological and immunogenetic research and has the potential for becoming one of the most important nonmammalian vertebrate research models. With this in mind, we initiated a systematic study of the zebrafish major histocompatibility complex (Mhc) genes. In this report, we describe the cloning and characteristics of the zebrafish class I A genes coding for the alpha chains of the alpha beta heterodimer and thus complete the identification of all four classes and subclasses of the Mhc in this species. We describe the full class I alpha cDNA sequence as well as the exon-intron organization of the class I A genes, including intron sequences. We identify three families of class I A genes which we designate Brre-UAA, -UBA, and -UCA. The three families originated about the time of the divergence of cyprinid and salmonid fishes. All three families are members of an ancient lineage that diverged from another, older lineage also represented in cyprinid fishes before the radiation of teleost orders. The fish class I A genes therefore evolve differently from mammalian class I A genes, in which the establishment of lineages and families mostly postdates the divergence of orders.

Evidence for insertion of a new intron into an Mhc gene of perch-like fish

The evolution of the major histocompatibility complex (Mhc) has been studied to understand the origin of the immune system, of which it constitutes an essential part. In the present study, the Mhc is used to shed light on questions regarding the origin of introns and the phylogeny of fishes. The organization of the coding (exon) and non-coding (intron) regions of both class I and class II major histocompatibility complex (Mhc) genes is highly conserved in all vertebrate classes; the only variation observed until now is in the number of exons encoding the membrane-anchoring part. Moreover, there is a good correspondence between the exon-intron organization at the DNA level and the division into structurally and functionally defined domains at the protein level. Here we describe the first major exception to this uniformity. The immunoglobulin-like domain of the class II beta-chains in perch-like fishes (Percomorpha) is not encoded in one exon, as it is in all other vertebrates studied thus far, but in two exons. The length of the extra intron varies from gene to gene and from species to species, but is generally less than 200 base pairs (b.p.). Only one of the sequenced introns is about 500 b.p. long. In some of the genes, the intron contains a hexamer repeat. The repeat is present in the transcript at the site at which the intron interrupts exon 3 in the genomic DNA. The intron may therefore have arisen by repeated tandem duplication of this sequence.(ABSTRACT TRUNCATED AT 250 WORDS)

[Treatment with cyclosporine of refractory rheumatoid arthritis]

Cyclosporine may be useful in the treatment of rheumatoid arthritis refractory to other immunosuppressive agents, in doses of less than 10 mg/kg/day to minimize its nephrotoxic potential, that is enhanced with prolonged use or concomitant administration of anti-inflammatory drugs. We report 15 patients aged 50 +/- 12 years with erosive rheumatoid arthritis lasting 5 +/- 4 years and refractory to other immunosuppressive agents. They were studied during one year and received cyclosporine in initial doses of 2.5 mg/kg/day that were increased to 5 mg/kg/day, assessing clinical response, blood pressure and serum creatinine. Nine patients, that received a maximal dose of 3.4 +/- 0.7 mg/kg/day during 7 +/- 4 months, improved; a 30% increase in creatinine was observed in 3, blood pressure raised in six and two had hepatic toxicity. In the six patients that did not improve, the mean treatment lapse was 4 +/- 3 months and the maximal dose achieved was 2.7 mg/kg/day; creatinine increased in one and blood pressure increased in 4. It is concluded that although the clinical response to cyclosporine was good, only 4 patients completed one year of treatment, due to the frequent secondary effects of the drug.

Identification of major histocompatibility complex genes in the guppy, Poecilia reticulata

The guppy, Poecilia reticulata, a teleostean fish of the order Cyprinodontiformes, has been used extensively in studies of host-parasite interactions, courtship behavior, and mating preference, as well as in ecological and evolutionary genetics. A related species was among the first poikilotherm vertebrates to be used in the study of histocompatibility genes. All these studies could benefit from the identification and characterization of the guppy major histocompatibility complex (Mhc) genes. Here, both class I and class II genes of the guppy are described. The number of expressed loci, as determined by representation of clones in a cDNA library, sequencing, and Southern blot analysis, may be low in both Mhc classes: combined evidence suggests that there may be one expressed class II locus only and one or two expressed class I loci. The variability of aquaristic guppy stocks is very low: only three and two genes have been detected at the class I and class II loci, respectively, in the stocks examined. This genetic paucity is most likely the consequence of breeding practices employed by aquarists and commercial establishments. Limited sampling of wild guppy populations revealed extensive Mhc polymorphism at loci of both classes in nature. Comparison of guppy Mhc sequences with those of other vertebrates has revealed the existence of a set of insertions/deletions which can be used as characters in cladistic analysis to infer phylogenetic relationships among vertebrate taxa and the Mhc genes themselves. These indels are particularly frequent in the regions coding for the loops of alpha 1 and alpha 2 domains of class I proteins.

Organization of Mhc class II B genes in the zebrafish (Brachydanio rerio)

Using three genomic phage libraries, we isolated 26 clones from the zebrafish MHC class II B region. By restriction mapping, the clones could be arranged into six clusters, most clusters consisting of several overlapping clones. The combined clusters cover a total of 161 kb of the zebrafish class II region. Hybridization with specific probes demonstrated the presence in the clusters of two class II A and six class II B genes. Sequencing of the B genes revealed that they represented six different families of class II loci. Only two of the class II B and one of the class II A genes are complete; the others are truncated pseudogenes. Only one of the class II B loci shows extensive restriction fragment length polymorphism. This is also the only locus found to be transcribed in organs with large numbers of lymphoid or myeloid cells. The zebrafish class II genes have promoter regions with sequence elements found previously in mammalian genes and known to be involved in regulation of expression. The exon-intron organization of the zebrafish class II genes is similar to that of the mammalian genes, but the introns are characteristically short, ranging in length from 74 to 362 bp. The distances between A and B genes in a given pair are also short, but the distances between B genes are as long as or longer than those between mammalian class II B genes. All of the zebrafish class II B genes appear to have arisen by duplication and diversification of a single ancestral B gene after the separation of bony fishes from other vertebrate taxa.

Alu elements of the primate major histocompatibility complex

The chromosomal region constituting the major histocompatibility complex (MHC) has undergone complex evolution that is often difficult to decipher. An important aid in the elucidation of the MHC evolution is the presence of Alu elements (repeats) which serve as markers for tracing chromosomal rearrangements. As the first step toward the establishment of sets of evolutionary markers for the MHC, Alu elements present in selected MHC haplotypes of the human species, the gorilla, and the chimpanzee were identified. Restriction fragments of cosmid clones from the libraries of the three species were hybridized with Alu-specific probes, Alu elements were amplified by the polymerase chain reaction, and the amplification products were sequenced. In some cases, sequences of the regions flanking the Alu elements were also obtained. Altogether, 31 new Alu elements were identified, representing six Alu subfamilies. The average density of Alu elements in the MHC is one element per four kilobases (kb) of sequence. Alu elements have apparently been inserted steadily into the MHC over the last 65 million years (my). On average, one Alu element is inserted into the primate MHC every 4 my. Analysis of the human DR3 haplotype supports its origin by duplication from an ancestral haplotype consisting of DRB1 and DRB2 genes. The sharing of an old Alu element by the DRB1 and DRB2 genes, in turn, supports their divergence from a common ancestor more than 55 my ago.

The origin of the primate Mhc-DRB genes and allelic lineages as deduced from the study of prosimians

MHC class II genes of the DRB family were partially sequenced from 10 individuals representing six species of prosimians: Galago senegalensis, G. moholi, Otolemur garnetti, Loris tardigradus, Petterus (Lemur) fulvus, and Lemur catta. Altogether, 41 different genes were discerned, all distinct from genes identified previously. Comparative analysis of the sequences has led to the following conclusions. First, the DRB loci present in human populations diverged from one another before the divergence of prosimian and anthropoid primates. Second, major allelic lineages of the DRB1 locus, such as DRB1*03 (DRB1*13) and DRB1*04, were established more than 85 million years ago. Third, the DRB6 gene was inactivated before the separation of prosimians and anthropoids, and has remained a pseudogene for more than 85 million years. Fourth, the primate DRB region is structurally and functionally unstable. In Lemur catta, for example, all DRB genes have apparently been lost and their function taken over by DOB and/or DPB genes. DRB genes are, however, present in a related species, Petterus (Lemur) fulvus. Fifth, the prosimian DRB3 genes are all inactive; their function seems to have been taken over by new genes. Sixth, several of the prosimian DRB genes and pseudogenes have recently been duplicated. In Otolemur garnetti, for example, one chromosome carries at least three copies of the DRB3 pseudogene.

The origin of the primate Mhc-DRB genes and allelic lineages as deduced from the study of prosimians

MHC class II genes of the DRB family were partially sequenced from 10 individuals representing six species of prosimians: Galago senegalensis, G. moholi, Otolemur garnetti, Loris tardigradus, Petterus (Lemur) fulvus, and Lemur catta. Altogether, 41 different genes were discerned, all distinct from genes identified previously. Comparative analysis of the sequences has led to the following conclusions. First, the DRB loci present in human populations diverged from one another before the divergence of prosimian and anthropoid primates. Second, major allelic lineages of the DRB1 locus, such as DRB1*03 (DRB1*13) and DRB1*04, were established more than 85 million years ago. Third, the DRB6 gene was inactivated before the separation of prosimians and anthropoids, and has remained a pseudogene for more than 85 million years. Fourth, the primate DRB region is structurally and functionally unstable. In Lemur catta, for example, all DRB genes have apparently been lost and their function taken over by DOB and/or DPB genes. DRB genes are, however, present in a related species, Petterus (Lemur) fulvus. Fifth, the prosimian DRB3 genes are all inactive; their function seems to have been taken over by new genes. Sixth, several of the prosimian DRB genes and pseudogenes have recently been duplicated. In Otolemur garnetti, for example, one chromosome carries at least three copies of the DRB3 pseudogene.

Zebrafish Mhc class II alpha chain-encoding genes: polymorphism, expression, and function

Its small size and short generation time renders the zebrafish (Brachydanio rerio) an ideal vertebrate for immunological research involving large populations. A prerequisite for this is the identification of the molecules critical for an immune response in this species. In earlier studies, we cloned the zebrafish genes coding for the beta chains of the class I and class II major histocompatibility complex (Mhc) molecules. Here, we describe the cloning of the zebrafish alpha chain-encoding class II gene, which represents the first identification of a class II A gene in teleost fishes. The gene, which is less than 3 kilobases (kb) distant from one of the beta chain-encoding genes, is approximately 1.2 kb long and consists of four exons interrupted by very short (< 200 base pairs) introns. Its organization is similar to that of the mammalian class II A genes, but its sequence differs greatly from the sequence of the latter (36% sequence similarity). Among the most conserved parts is the promoter region, which contains X, Y, and TATA boxes with high sequence similarity to the corresponding mammalian boxes. The observed striking conservation of the promoter region suggests that the regulatory system of the class II genes was established more than 400 million years ago and has, principally, remained the same ever since. Like the DMA, but unlike all other mammalian class II A genes, the zebrafish gene codes for two cysteine residues which might potentially be involved in the formation of a disulfide bond in the alpha 1 domain. The primary transcript of the gene is 1196 nucleotides long and contains 708 nucleotides of coding sequence. The gene is expressed in tissues with a high content of lymphoid/myeloid cells (spleen, pronephros, hepatopancreas, and intestine). The analyzed genomic and cDNA sequences are probably derived from different loci (their overall sequence similarity in the coding region is 73% and their 3' untranslated regions are highly divergent from each other). The genes are apparently functional. Comparison of genes from different zebrafish populations reveals high exon 2 variability concentrated in positions coding for the putative peptide-binding region. Phylogenetic analysis suggests that the zebrafish class II A genes stem from a different ancestor than the mammalian class II A genes and the recently cloned shark class II A gene.

[Pharmacological modification of prolactinemia. Effects on cellular immune function in normal subjects]

Prolactin markedly influences cellular and humoral immunity in animals, but there is little information on its role in men. The aim of this work was to study the immune effects of pharmacological modification of prolactin levels in 5 healthy individuals. Peripheral blood mononuclear cell proliferative response to mitogens and antigens, interleukin-2 (IL-2) production, soluble and membrane IL-2 receptor expression in peripheral blood mononuclear cells and serum soluble IL-2 receptors were successively measured during normoprolactinemia, during bromocriptine induced hypoprolactinemia and during metoclopramide induced hyperprolactinemia. There was a significant increase in cellular proliferation during hypoprolactinemia when compared with hyperprolactinemia. No concomitant changes in soluble or membrane receptor expression or IL-2 production were observed. It is concluded that lymphocyte proliferative response to mitogens is dependent on prolactin levels in man and that this effects is not mediated by IL-2 or its receptors. These results may be potentially relevant in clinic since changes in serum prolactin have been described in different autoimmune diseases.

Conservative evolution of the Mbc-DP region in anthropoid primates

To determine the organization of the DP region in the Mbc of anthropoid primates, we constructed contig maps from cosmid clones of the chimpanzee and orangutan, representatives of the infraorder Catarrhini, as well as of the cotton-top tamarin, a representative of the infraorder Platyrrhini. We found the maps to be remarkably similar to each other and to the previously published map of the human DP region. In each of the four species, the DP region consists of four loci arranged in the same order (DPB2 . . . DPA2 . . . DPB1 . . . DPA1) and in the same transcriptional orientation (tail-to-tail). The regions in the four species are of approximately the same length and many of the restriction sites are shared between species. The inserts of most Alu elements, of a ribosomal protein pseudogene, and of an IgC epsilon-like pseudogene are found in corresponding positions in all four species. The data indicate that the human-type organization of the DP region was established before the divergence of the Catarrhini and Platyrrhini lines more than 37 million years ago and that it has remained principally intact since that time. This conservation of the DP region is in striking contrast to the evolutionary instability of certain other Mbc regions, in particular those occupied by the DRB or C4 and CYP21 loci. We interpret the stability of the DP region as an indication that the region is being phased out functionally.

Dating the primigenial C4-CYP21 duplication in primates

C4 and CYP21 are two adjacent, but functionally unrelated genes residing in the middle of the mammalian major histocompatibility complex (Mhc). The C4 gene codes for the fourth component of the complement cascade, whereas the CYP21 gene specifies an enzyme (cytochrome P450c21) of the glucocorticoid and mineralocorticoid pathways. The genes occur frequently in multiple copies on a single chromosome arranged in the order C4 ... CYP21 ... C4 ... CYP21. The unit of duplication (a module) is the C4-CYP21 gene pair. We sequenced the flanking regions of the C4-CYP21 modules and the intermodular regions of the chimpanzee, gorilla, and orangutan, as well as the intermodular region of an Old World monkey, the pigtail macaque. By aligning the sequences, we could identify the duplication breakpoints in these species. The breakpoint turned out to be at exactly the same position as that found previously in humans. The sequences flanking paralogous genes in the same species were found to be more similar to one another than sequences flanking orthologous genes in different species. We interpret these results as indicating that the original (primigenial) duplication occurred before the separation of apes from Old World monkeys more than 23 million years ago. The nature of the sequence at the breakpoint suggests that the duplication occurred by nonhomologous recombination. Since then, the C4-CYP21 haplotypes have been expanding and contracting by homologous crossing over which has homogenized the sequences in each species.(ABSTRACT TRUNCATED AT 250 WORDS)

Cloning of the beta 2-microglobulin gene in the zebrafish

The beta 2-microglobulin (beta 2m) is a protein found in the serum in a free form and on the cell surface in a form noncovalently associated with the alpha chain of the class I major histocompatibility complex (Mhc) molecules. In mammals, the beta 2m-encoding gene (B2m) is found on a chromosome different from the Mhc proper. We have isolated and characterized the B2m gene of the zebrafish, Brachydanio rerio, family Cyprinidae. We obtained both cDNA and genomic clones of the Brre-B2m gene. The cDNA clones contained the entire coding sequence, the entire 3' untranslated (UT) region, and at least part of the 5'UT region. The genomic clone contained the entire Brre-B2m gene. The coding sequence specifies 97 amino acid residues of the mature protein so that the zebrafish beta 2m is two residues shorter than human and one residue shorter than cattle, fowl, or turkey beta 2m (codons at positions 85 and 86 have been deleted in the Brre-B2m gene). The amino acid and nucleotide sequence similarities between zebrafish and human beta 2m (B2m) are 45% and 59%, respectively. Approximately 24% of the positions are invariant and an additional 9% show only conservative substitutions in comparisons which include all known beta 2m sequences (fish, avian, and mammalian). Most of the conserved positions are in the beta strands (some 47% of the beta-strand positions are conserved in the three vertebrate classes). The Brre-B2m gene consists of four exons separated by three introns. All of the introns are considerably shorter than the corresponding introns in the mammalian B2m genes. The coding sequences of the cDNA and the genomic clones are almost identical but the sequences of the 3'UT regions differ at 1.7% of the sites, suggesting that the genes borne by these clones might have diverged at least 0.7 million years (my) ago. In contrast to the human B2m gene, the Brre-B2m gene shows no bias in the distribution of the CpG dinucleotides: the dinucleotides are distributed evenly along the entire available sequence. The haploid genome of the zebrafish contains only one copy of the B2m gene.

Different modes of Mhc evolution in primates

The human major histocompatibility complex (Mhc) is a chromosomal segment approximately 4 million bp long that contains > or = 84 genes. Some of these genes code for the class I and class II molecules, while the remaining genes code for complement components, cytochrome P450, tumor necrosis factor, and many other, unrelated proteins. We demonstrate on three examples (DP, C4-CYP21, and DRB) that different regions of the Mhc have different evolutionary histories. The organization of the DP region, which in humans contains four genes, was established in the ancestral Anthropoidea or earlier and has not changed since. The duplication that generated the two C4-CYP21 modules occurred in the ancestral Catarrhini or earlier, but the region has been undergoing periodic homogenizations via unequal crossing-over, which make paralogous genes in the same species more similar to each other than to orthologous genes of different species. The eight or nine genes of the DRB region were also generated in the ancestral Catarrhini, but the region has since been subject to frequent rearrangements, which generated various DRB haplotypes. Not only the alleles but, in part, also the haplotype polymorphism is evolving transspecifically. The DRB region of the Platyrrhini has an origin different from that of the Catarrhini. The picture emerging from these studies is that of both stability in some regions of the Mhc and tremendous evolutionary instability in other regions.

Major histocompatibility complex class II genes of zebrafish

Twenty cDNA clones derived from beta-chain-encoding class II genes of the zebrafish (Brachydanio rerio) major histocompatibility complex (MHC) have been sequenced. They fall into three groups identifying three loci of expressed genes. The length and organization of these genes are similar to those of their mammalian homologs. Amplification by polymerase chain reaction and sequencing of genomic DNA from zebrafish collected at different locations in India indicate the existence of a fourth group of sequences (fourth locus). A high degree of polymorphism at the B. rerio MHC loci and concentration of variability to the putative peptide-binding region of the beta 1-domain-encoding part of the gene are also indicated. Large genetic distances between alleles suggest trans-specific evolution of fish MHC polymorphism. Zebrafish genes appear to be derived from a different ancestor than the various class II gene families of other vertebrates. In spite of great sequence divergence between fish and mammalian MHC genes, there seems to be a striking conservation in their overall organization.

Anticardiolipin antibodies in acute rheumatic fever

Recent reports describe the association of antiphospholipid antibodies (aPL) with chorea or severe heart valve lesions in systemic lupus erythematosus, lupus-like disease, or the primary antiphospholipid antibody syndrome. We conducted a case series and a case-control investigation of patients with rheumatic fever with Sydenham chorea or other manifestations of rheumatic fever for anticardiolipin antibodies (aCL) during the acute attack and disease remission. Eighty percent of patients were positive for aCL during the rheumatic fever attack vs 40% when inactive (p = 0.035); IgG and IgM aCL increased significantly with disease activity. Individuals with or without Sydenham chorea were equally positive for aCL (76 and 83%, respectively). A significant association was found between IgM aCL and carditis: All patients with valvulitis had IgM aCL (100%) vs 37% of patients without valvular involvement (p = 0.02). aPL may play a role in the pathogenesis of some clinical manifestations of acute rheumatic fever.