Characterization of the primary structure of T cell receptor beta chains in cells infiltrating the salivary gland in the sicca syndrome of HIV-1 infection. Evidence of antigen-driven clonal selection suggested by restricted combinations of V beta J beta gene segment usage and shared somatically encoded amino acid residues

Infection with HIV-1 occasionally results in a sicca syndrome, termed the diffuse infiltrative lymphocytosis syndrome, characterized by infiltration of the salivary glands with a predominance of CD8 T cells. This response is strongly associated with certain MHC class I and class II alleles. To define the salivary gland T cell receptor (TCR) repertoire, the primary structure of the TCR beta-chains was determined using in situ cDNA synthesis followed by the "anchored" polymerase chain reaction. The sequences of 59 beta-chains from five individuals with diffuse infiltrative lymphocytosis syndrome shared structural features suggesting antigenic clonal selection. Certain combinations of V beta J beta gene segments were selectively overrepresented in the repertoire sample, demonstrating a common restricted usage of certain V beta and J beta gene segments. The beta-chains derived from these overrepresented V beta J beta combinations revealed a preference for specific amino acids at position 97 in the third complementarity-determining region, a residue postulated to contact peptide antigen. Moreover, the nucleotides encoding this position were not germline in origin. TCR beta-chains in nonoverrepresented V beta J beta combinations did not exhibit preferential usage of selected somatically encoded residues. The pattern of TCR beta-chains expressed in the salivary gland of a control person with primary Sjögren's syndrome was considerably more heterogeneous and different from that found in diffuse infiltrative lymphocytosis syndrome.

Tissue infiltration in a CD8 lymphocytosis syndrome associated with human immunodeficiency virus-1 infection has the phenotypic appearance of an antigenically driven response

HIV-1 infection may initiate to an HLA-associated response designated diffuse infiltrative lymphocytosis syndrome, characterized by increased numbers of circulating CD8 T cells that infiltrate salivary glands, lungs, gastrointestinal tract, and kidneys. Since this response could either be an antigenically driven process induced by HIV-1 or a lymphoproliferation of cells with neoplastic or unusual features, we sought to define the phenotype of the cellular populations, the nature of tissue derangement, and the tissue localization of virus in diffuse infiltrative lymphocytosis syndrome. Circulating CD8 T cells were greatly increased while CD4 T cell numbers remained in the range found in asymptomatic seropositive persons. The majority of CD8 and CD4 T cells in both blood and tissues had the memory phenotype of CD29+ (beta 1 integrin) and CD11a+/CD18 (beta 2 integrin) expression, but lacked markers of recent activation. A proportion of the circulating CD8 T cells also expressed CD57 (Leu 7) but not other markers of natural killer cells. HIV-encoded proteins were identified in tissue macrophages located in periacinar areas of the salivary glands. CD54 (intercellular adhesion molecule-1), a ligand for the CD11a integrin, was strongly expressed on postcapillary venule endothelium within lymphoid foci, and HLA-DR molecules were found on limited regions of ductular epithelium adjacent to lymphoid aggregates. These findings suggest that (a) the visceral lymphocytic infiltration in diffuse infiltrative lymphocytosis syndrome is an antigen-driven, and MHC-determined, host immune response to an element associated with HIV-1 infection, and (b) that the specific adhesive molecule interactions mediating the cellular influx, as well as the subsequent tissue damage, reflect altered patterns of gene expression in tissues undergoing an immune response.

Alteration of synoviocytes by inflammation--the source of a persistent non-immunologic drive in synovitis: analysis of levels of mRNA expression by a simple multi-gene assay

A solid phase hybridization assay was developed to assess simultaneously the level of transcription of multiple genes in inflammatory tissues and in derivative cell lines. It involves binding of a labelled cDNA probe to plasmids containing cDNAs of the genes of interest in excess concentration applied to a nylon membrane in a dot blot format. After hybridization under stringent conditions, the blot is washed and counts enumerated. Levels of mRNA are compared between different samples by normalization to GAPDH. The results indicate that mesenchymal cells isolated from inflammatory synovia exhibit alterations in the pattern of gene expression which distinguish them from similarly isolated and cultured cells from non-inflammatory synovia. These patterns are sustained through multiple passages in tissue culture, suggesting that this may reflect a persistently altered state of fibroblast differentiation induced by exposure to an inflammatory milieu.

Diffuse infiltrative lymphocytosis syndrome: a disorder occurring in human immunodeficiency virus-1 infection that may present as a sicca syndrome

Certain adults and children infected with the human immunodeficiency virus(HIV)-1 developed a disorder termed diffuse infiltrative lymphocytosis syndrome (DILS) that, although having certain similarities to classic Sjögren's syndrome, manifests distinctive clinical, serologic, immunologic, and immunogenetic characteristics. DILS is characterized by circulating CD8 lymphocytosis and apparently antigen-driven CD8 T-cell infiltration of salivary and lacrimal gland, pulmonary, renal, gastrointestinal, and breast tissues. The disproportionately greater degree of salivary gland enlargement and extraglandular disease, as well as the low frequency of autoantibodies and differing HLA associations, serve to distinguish DILS from classic Sjögren's syndrome.

Constitutive production of inflammatory and mitogenic cytokines by rheumatoid synovial fibroblasts

Conditioned media obtained from fibroblasts cultured from rheumatoid and certain other inflammatory synovia were observed to stimulate [3H]thymidine incorporation in an indicator murine fibroblast line. Synovial fibroblasts derived from the joints of patients with osteoarthritis did not display this property. This effect persisted in culture for many weeks and occurred in the absence of co-stimulatory immune cells. Antibody neutralization studies implicated a role for basic fibroblast growth factor (bFGF), transforming growth factor beta (TGF-beta), granulocyte/macrophage colony-stimulating factor (GM-CSF), and interleukin 1 beta (IL-1 beta) in the increased proliferative activity of synovial fibroblast-conditioned media. Synovial cell synthesis of bFGF, TGF beta 1, GM-CSF, IL-1 beta, and IL-6 was confirmed by 35S-methionine labeling and immunoprecipitation. The constitutive production of inflammatory and mitogenic cytokines by synovial fibroblasts may represent the result of long-term, phenotypic changes that occurred in vivo. Persistent cytokine production by synovial fibroblasts may play an important role in the continued recruitment and activation of inflammatory cells in chronic arthritis and in the formation of rheumatoid pannus.

An approach to the human immunodeficiency virus-positive patient with a spondyloarthropathic disease

One of the unanticipated consequences of infection with the human immunodeficiency virus (HIV) is the appearance of various rheumatic syndromes that traditionally have been thought to result from inappropriate overactivity of the immune system. This distinctive spectrum of rheumatic syndromes has been well described; however, the therapeutics and specific patient management as well as the significance of these disorders for diagnostic classification of the rheumatic disorders have not received a great degree of attention. This article focuses on these areas with emphasis on (1) the nosology of the arthrocutaneous musculoskeletal syndromes with HIV, (2) clinical presentation of the various syndromes, (3) current concepts regarding the etiopathogenesis of the spondyloarthropathic form of arthritis in this setting, and (4) an approach to therapy.

Two pathways of CD11b/CD18-mediated neutrophil aggregation with different involvement of protein kinase C-dependent phosphorylation

The characteristics of homotypic neutrophil aggregation, mediated by the adhesion molecule CD11b/CD18, differ according to whether activation takes place via intracellular protein kinase C(PKC) inducers or chemoattractants. In response to diacylglycerol (DAG) analogues such as PMA and 1,2-dioctanoyl-sn-glycerol, a prolonged cellular aggregation occurs that is associated with intense phosphorylation of the CD18 beta-chain. In response to the chemoattractant FMLP, a more transient aggregation event results that is associated with minimal beta-chain phosphorylation. By using the PKC inhibitor staurosporine, we now show that these differences are likely to reflect two different pathways of activation. Both aggregation and phosphorylation induced by DAG analogues are completely abolished by staurosporine in a parallel dose-dependent manner. Conversely, FMLP-induced aggregation is enhanced and prolonged by staurosporine whereas the associated minimal phosphorylation event is further diminished by staurosporine. Accordingly, activation of neutrophil aggregation by DAG analogues is associated with and presumably due to phosphorylation of the CD18 beta-chain. This intense phosphorylation occurs via a staurosporine-sensitive kinase such as PKC. FMLP, on the other hand, appears to activate CD11b/CD18 by a distinct mechanism. This latter mechanism does not seem to be dependent on what may be a minor PKC-induced phosphorylation of the beta-chain, and indeed is enhanced by inhibition of PKC. Of note, staurosporine was also found to cause selective release of specific granules with concomitant increase in surface display of CD11b/CD18. These data further support previous observations that up-regulation of this adhesive molecule is not the primary event in the induction of cellular adhesiveness.

Two pathways of CD11b/CD18-mediated neutrophil aggregation with different involvement of protein kinase C-dependent phosphorylation

The characteristics of homotypic neutrophil aggregation, mediated by the adhesion molecule CD11b/CD18, differ according to whether activation takes place via intracellular protein kinase C(PKC) inducers or chemoattractants. In response to diacylglycerol (DAG) analogues such as PMA and 1,2-dioctanoyl-sn-glycerol, a prolonged cellular aggregation occurs that is associated with intense phosphorylation of the CD18 beta-chain. In response to the chemoattractant FMLP, a more transient aggregation event results that is associated with minimal beta-chain phosphorylation. By using the PKC inhibitor staurosporine, we now show that these differences are likely to reflect two different pathways of activation. Both aggregation and phosphorylation induced by DAG analogues are completely abolished by staurosporine in a parallel dose-dependent manner. Conversely, FMLP-induced aggregation is enhanced and prolonged by staurosporine whereas the associated minimal phosphorylation event is further diminished by staurosporine. Accordingly, activation of neutrophil aggregation by DAG analogues is associated with and presumably due to phosphorylation of the CD18 beta-chain. This intense phosphorylation occurs via a staurosporine-sensitive kinase such as PKC. FMLP, on the other hand, appears to activate CD11b/CD18 by a distinct mechanism. This latter mechanism does not seem to be dependent on what may be a minor PKC-induced phosphorylation of the beta-chain, and indeed is enhanced by inhibition of PKC. Of note, staurosporine was also found to cause selective release of specific granules with concomitant increase in surface display of CD11b/CD18. These data further support previous observations that up-regulation of this adhesive molecule is not the primary event in the induction of cellular adhesiveness.

Association of chronic Lyme arthritis with HLA-DR4 and HLA-DR2 alleles

BACKGROUND AND METHODS

A small percentage of patients infected with Borrelia burgdorferi have chronic Lyme arthritis that does not respond to antibiotic therapy. To learn whether genetically determined variations in the host immune response might account for such outcomes, we determined the immunogenetic profiles of 130 patients with various manifestations of Lyme disease.

RESULTS

Of the 80 patients with arthritis, 57 percent of those with chronic arthritis (12 to 48 months in duration) had the HLA-DR4 specificity; only 23 percent of those with arthritis of moderate duration (6 to 11 months) and only 9 percent of those with arthritis of short duration (1 to 5 months) had this specificity (P = 0.003). After the HLA-DR4-positive patients were excluded from each group, a secondary association was noted with HLA-DR2, which was found in 75 percent of the remaining patients with chronic arthritis and in 50 percent of those with arthritis of moderate duration, but in only 20 percent of those with arthritis of short duration (P = 0.023). Altogether, 25 of the 28 patients with chronic arthritis (89 percent) had HLA-DR2 or HLA-DR4, or both, as compared with 27 percent of those with arthritis of short duration (relative risk, 22; P = 0.00006). These HLA specificities appeared to act as independent, dominant markers of susceptibility. Nucleotide-sequence typing, performed in five patients with chronic arthritis, identified the HLA-DR2 allele as Dw2 (DR beta 1*1501), and the HLA-DR4 alleles as Dw4, Dw14, and Dw13 (DR beta 1*0401, DR beta 1*0404, and DR beta 1*0403, respectively). The presence of HLA-DR4 in patients with arthritis was associated with a lack of response to antibiotic therapy (P = 0.01).

CONCLUSIONS

Particular Class II major histocompatibility genes determine a host immune response to B. burgdorferi that results in chronic arthritis and lack of response to antibiotic therapy.

Effective separation of the 52 kDa SSA/Ro polypeptide from the 48 kDa SSB/La polypeptide by altering conditions of polyacrylamide gel electrophoresis

A method is described for the separation of the 52 kDa SSA/Ro polypeptide from the 48 kDa SSB/La polypeptide. These two proteins anomalously co-migrate with the same relative mass under conditions of conventional sodium dodecyl sulfate polyacrylamide gel electrophoresis according to Laemmli using a stock solution of acrylamide: bisacrylamide 30:0.8, ratio = 37.5. A higher ratio of monomer to cross-linker, ratio = 172.4 used in a 15% acrylamide solution, readily separates the two peptide chains. This method facilitates the detection of the 52 kDa SSA/Ro component which otherwise might have been incorrectly assigned as a 48 kDa SSB/La polypeptide.

A diffuse infiltrative CD8 lymphocytosis syndrome in human immunodeficiency virus (HIV) infection: a host immune response associated with HLA-DR5

STUDY OBJECTIVE

To describe the clinical, immunologic, and immunogenetic features of a diffuse infiltrative lymphocytic disorder resembling Sjögren syndrome in persons infected with human immunodeficiency virus (HIV).

DESIGN

Clinical case study.

SETTING

University-affiliated hospitals and outpatient clinics.

PATIENTS

Consecutive sample of 17 patients.

MEASUREMENTS AND MAIN RESULTS

All of the 17 patients had bilateral parotid gland enlargement; 14 had xerostomia and 6 had xerophthalmia. Of the 17 patients, 14 had generalized lymphadenopathy, 10 had histologically proved lymphocytic interstitial pneumonitis, 4 had neurologic involvement, and 3 had lymphocytic infiltration of the gastrointestinal tract. Gallium scanning in all of 11 tested patients showed abnormal salivary gland uptake. Minor salivary gland biopsies showed more than 2 lymphocytic foci per 4 mm2 tissue in all of 11 tested patients, the infiltrate consisting predominantly of CD8 cells. Fifteen patients had circulating CD8 lymphocytosis; the principal phenotype of these cells was CD8+ CD29+. Rheumatoid factor and antinuclear antibodies were infrequent, and none of the patients had anti-Ro/SS-A or anti-La/SS-B antibodies. HLA-DR5 was significantly more frequent in the black patients (10 of 12) compared with controls (13 of 45). Only one patient developed an opportunistic infection during 544 patient-months of study, and none has died of AIDS.

CONCLUSIONS

A distinct syndrome primarily characterized by parotid gland enlargement, sicca symptoms, and pulmonary involvement occurs in HIV infection. This disorder is associated with CD8 lymphocytosis and the presence of HLA-DR5, and appears to be a genetically determined host immune response to HIV.

Constitutive and induced phosphorylation of the alpha- and beta-chains of the CD11/CD18 leukocyte integrin family. Relationship to adhesion-dependent functions

We sought to determine whether the activation event which renders the CD11/CD18 leukocyte integrin/Leu-CAM glycoproteins capable of promoting cell to cell adhesion was associated with the induced posttranslational modification of phosphorylation. In neutrophils, two species of alpha-chains, a predominant CD11b 165-kDa subunit and a minor 150-kDa CD11c subunit were found to be constitutively phosphorylated. However, the 95-kDa CD18 common beta-chain was not phosphorylated in resting cells but became strongly phosphorylated in cells incubated with PMA. The beta-chain was phosphorylated in a dose-related manner within 1 min of the addition of PMA, reached maximal intensity between 4 to 10 min, and remained fully phosphorylated at 30 min. The similarities of the kinetics of homotypic aggregation induced by PMA to the time course of phosphorylation suggest that phosporylation may be relevant to at least this type of Leu-CAM-dependent adhesion. In contrast, in the presence of FMLP which induces aggregation with different kinetics than PMA, no phosphorylation of the common beta-chain was observed over a time interval of from 30 s to 10 min further emphasizing the apparent differences in the two modes of activation to an adhesive state. The phosphorylated species on neutrophils were readily detected by immunoprecipitation with each CD18 mAb and most but not all CD11b mAb which otherwise precipitated 125I-labeled CD11b species suggesting that the CD11b alpha-chain labelled with 32P may differ slightly from the 125I-labeled species in terms of its recognition by certain CD11b mAb. In mononuclear cells, similar constitutive phosphorylation of the CD11a and CD11c alpha-chains was observed that remained unchanged in the presence of either FMLP or PMA. As was demonstrated in neutrophils, phosphorylation of the CD18 beta-chains of mononuclear cells was not constitutive but was induced in the presence of PMA and not FMLP. Taken together these data suggest the existence of specific recognition sites on beta-chains for a regulatory kinase-phosphatase system.

Constitutive and induced phosphorylation of the alpha- and beta-chains of the CD11/CD18 leukocyte integrin family. Relationship to adhesion-dependent functions

We sought to determine whether the activation event which renders the CD11/CD18 leukocyte integrin/Leu-CAM glycoproteins capable of promoting cell to cell adhesion was associated with the induced posttranslational modification of phosphorylation. In neutrophils, two species of alpha-chains, a predominant CD11b 165-kDa subunit and a minor 150-kDa CD11c subunit were found to be constitutively phosphorylated. However, the 95-kDa CD18 common beta-chain was not phosphorylated in resting cells but became strongly phosphorylated in cells incubated with PMA. The beta-chain was phosphorylated in a dose-related manner within 1 min of the addition of PMA, reached maximal intensity between 4 to 10 min, and remained fully phosphorylated at 30 min. The similarities of the kinetics of homotypic aggregation induced by PMA to the time course of phosphorylation suggest that phosporylation may be relevant to at least this type of Leu-CAM-dependent adhesion. In contrast, in the presence of FMLP which induces aggregation with different kinetics than PMA, no phosphorylation of the common beta-chain was observed over a time interval of from 30 s to 10 min further emphasizing the apparent differences in the two modes of activation to an adhesive state. The phosphorylated species on neutrophils were readily detected by immunoprecipitation with each CD18 mAb and most but not all CD11b mAb which otherwise precipitated 125I-labeled CD11b species suggesting that the CD11b alpha-chain labelled with 32P may differ slightly from the 125I-labeled species in terms of its recognition by certain CD11b mAb. In mononuclear cells, similar constitutive phosphorylation of the CD11a and CD11c alpha-chains was observed that remained unchanged in the presence of either FMLP or PMA. As was demonstrated in neutrophils, phosphorylation of the CD18 beta-chains of mononuclear cells was not constitutive but was induced in the presence of PMA and not FMLP. Taken together these data suggest the existence of specific recognition sites on beta-chains for a regulatory kinase-phosphatase system.

Aspects of the spectrum, prevalence and disease susceptibility determinants of Reiter's syndrome and related disorders associated with HIV infection

Arthrocutaneous disorders including Reiter's syndrome, psoriasiform rashes, and other forms of chronic arthritis and enthesopathy, such as psoriatic arthritis, occur with an increased prevalence in the setting of HIV infection. Herein we describe the spectrum and prevalence of musculoskeletal and allied skin disorders as they occur in the setting of HIV infection. The role of genetic susceptibility in the development of these disorders is addressed. Based on the frequency of infectious agents capable of triggering reactive arthritis and the presence of HLA-B27 in 71% of these individuals, it is suggested that the disorder strongly resembles Reiter's syndrome as it occurs in the not HIV-infected group. Preliminary evidence indicates an enhanced penetrance for susceptibility among HLA-B27 individuals. In contrast, among HIV-infected patients with psoriasiform lesions there was no statistically significant association (P less than 0.05) between the presence of psoriasiform rash and the HLA alleles Cw6, B7, B17, Bw16, or Bw57 when compared with HIV-infected controls. These findings suggest that among HIV-infected individuals the development of Reiter's syndrome involves an immune recognition event primarily dependent upon HLA-B27 molecules in which an unknown antigen in the context of HLA-B27 is presented to CD8 lineage suppressor/cytotoxic cells. In contrast, the pathogenesis of psoriasiform lesions in HIV patients, despite their similarity to certain lesions in Reiter's syndrome, proceeds by distinct pathways that do not involve events influenced by specific polymorphic class I molecules.

A novel association of DQ alpha and DQ beta genes in the DRw10 haplotype. Determination of a DQw1 specificity by the DQ beta-chain

The association of the class II genes of the DRw10 haplotype from a cell line, NASC, initiated from a member of a well characterized family, was analyzed by sequencing cDNA clones corresponding to DR beta I, DQ alpha, and DQ beta genes. An identical haplotype was also identified in the Raji cell line. In addition to typing as DRw10 and DQw1 with HLA typing sera both, the NASC and Raji cell lines were shown to react strongly with the monoclonal antibodies 109d6 (specific for DRw10 beta 1 and DRw53 beta 2 gene products) and Genox 3.5.3 (specific for DQw1) and exhibited the restriction fragment length polymorphism indicative of a DRw10, DQw1 haplotype. The DR beta 1 gene corresponding to the DRw10 specificity was found to have a first domain sequence different from all other DR beta I genes. Sequence analysis of the 3'-untranslated region of this DR beta-chain gene showed a significant divergence from the 3' untranslated region of the DRw53 family of haplotypes and a lesser divergence from that of the DRw52 and DR1/DR2 families. The sequence of the DQ beta genes corresponding to the DQw1 specificity in the DRw10 haplotype was found to be identical to the DQ beta gene from a DR1, DQw1 haplotype. Surprisingly, however, the DQ alpha gene did not resemble other DQw1-like DQ alpha genes, but was identical in sequence to the DQ alpha gene found in DR4 haplotypes. The novel association of DQ alpha and DQ beta genes in the DRw10 haplotype revealed in these studies may result from a double recombinational event. More consequentially, these studies strongly suggest that the DQw1 specificity recognized by Genox 3.5.3 is determined by the DQ beta chain and is not affected by the DQ alpha-chain.

A novel association of DQ alpha and DQ beta genes in the DRw10 haplotype. Determination of a DQw1 specificity by the DQ beta-chain

The association of the class II genes of the DRw10 haplotype from a cell line, NASC, initiated from a member of a well characterized family, was analyzed by sequencing cDNA clones corresponding to DR beta I, DQ alpha, and DQ beta genes. An identical haplotype was also identified in the Raji cell line. In addition to typing as DRw10 and DQw1 with HLA typing sera both, the NASC and Raji cell lines were shown to react strongly with the monoclonal antibodies 109d6 (specific for DRw10 beta 1 and DRw53 beta 2 gene products) and Genox 3.5.3 (specific for DQw1) and exhibited the restriction fragment length polymorphism indicative of a DRw10, DQw1 haplotype. The DR beta 1 gene corresponding to the DRw10 specificity was found to have a first domain sequence different from all other DR beta I genes. Sequence analysis of the 3'-untranslated region of this DR beta-chain gene showed a significant divergence from the 3' untranslated region of the DRw53 family of haplotypes and a lesser divergence from that of the DRw52 and DR1/DR2 families. The sequence of the DQ beta genes corresponding to the DQw1 specificity in the DRw10 haplotype was found to be identical to the DQ beta gene from a DR1, DQw1 haplotype. Surprisingly, however, the DQ alpha gene did not resemble other DQw1-like DQ alpha genes, but was identical in sequence to the DQ alpha gene found in DR4 haplotypes. The novel association of DQ alpha and DQ beta genes in the DRw10 haplotype revealed in these studies may result from a double recombinational event. More consequentially, these studies strongly suggest that the DQw1 specificity recognized by Genox 3.5.3 is determined by the DQ beta chain and is not affected by the DQ alpha-chain.

Susceptibility to rheumatoid arthritis--the conformational equivalence hypothesis

The occurrence of the inappropriate immune response of rheumatoid arthritis is likely controlled by several alleles of class II DR beta chain genes of the major histocompatibility complex (MHC). These include certain of those that encode the serologically distinct DR1 and DR4 specificities. In a manner analogous to a segregation analysis, advantage was taken of ethnic differences in susceptibility associated with different alleles and parallel differences in the organization of the class II haplotypes that specify either similar or divergent serologic specificities. This permitted mapping of this disease susceptibility into a single equivalent polymorphic alpha helical conformation shared by each DR beta allelic product. This suggests that rheumatoid arthritis originates from a unitary immune recognition event initiated by particular class II MHC molecules.

A sicca syndrome in HIV infection: association with HLA-DR5 and CD8 lymphocytosis

A sicca syndrome with parotid enlargement, pulmonary insufficiency, and lymphadenopathy was seen in 12 patients infected with human immunodeficiency virus (HIV), only 1 of whom has had an opportunistic infection during 304 patient months of study. There was a striking increase in numbers of circulating CD8 lymphocytes and the prevalence of HLA-DR5 was greatly increased. In patients with this diffuse infiltrative lymphocytosis syndrome (DILS) the CD8 lymphocytosis, which probably depends on histocompatibility antigen status, may influence disease progression in HIV infection.

Acquired congenital heart block. Pattern of maternal antibody response to biochemically defined antigens of the SSA/Ro-SSB/La system in neonatal lupus

The molecular basis of autoantibody reactivity with components of the SSA/Ro-SSB/La particle exhibited by sera of mothers of infants with severe and permanent manifestations of neonatal lupus (NLE) was investigated using immunoblotting and immunoprecipitation. The characteristics of NLE that were studied included congenital complete heart block (CCHB), second degree heart block, and hepatic fibrosis. Antibodies specific for one or more components of the SSA/Ro-SSB/La particle were found in sera from all 20 mothers of permanently affected infants. However, no antibody specific for a single peptide of this particle was common to all sera. Using tissue extracts from a human cell substrate, 80% of these sera had antibodies to one or more components of the SSA/Ro particle demonstrable by immunoblotting. The predominant antibody response in the NLE group was to the newly recognized 52-kD SSA/Ro peptide component. In contrast, antibodies to the 60-kD SSA/Ro component although present, were the least represented and not significantly increased in frequency among mothers of these infants, compared with a group of 31 mothers with autoimmune diseases such as systemic lupus erythromatosus (SLE) but who had healthy offspring. Antibodies directed to the 48-kD SSB/La antigen were demonstrated in 90% of the NLE mothers often accompanying antibodies against the 52-kD SSA/Ro component. The combination of antibodies to 48- and 52-kD structures was significantly increased in the NLE group, with an odds ratio of 35. The type of cell or tissue substrate was shown to influence detectability of antibodies. The 52-kD SSA/Ro peptide and the 48-kD SSB/La peptide were abundant in cardiac tissues from fetuses aged 18-24 wk, further supporting the possible relevance of these peptides to heart block.

DNA sequence analysis of the HLA-DRw12 allele

The complete DNA sequence of a DR beta chain cDNA encoding the DRw12 allele has been determined. The sequence of this DRB1 allele reveals a structural relationship to the group of other DRB1 genes found on DRw52 haplotypes, such as DR3, -w11, -w13, -w14, and -w8. The structural similarities among this group of alleles are particularly evident in the first hypervariable as well as in the 3' untranslated region. The second hypervariable region contains a unique sequence not identified in any other DRB1 allele. The third hypervariable region appears to have arisen by gene conversion events involving two DRB1 chain genes, DR7 and DR1 or DR2/Dw21.