Some genetic aspects of systemic lupus erythematosus

Results and prognosis of kidney transplantation in lupus nephritis: Experience of an Argentine center

INTRODUCTION

Although RT has improved the survival of the population with ESRD due to all causes, renal outcomes in SLE are controversial. The objective of this study is to describe the characteristics and evolution of the patients and the kidney transplant in LN, and compare it with patients transplanted for other causes.

MATERIALS AND METHODS

Retrospective, observational, analytical, single-center study in which records of patients undergoing nephrotransplantation for LN were analyzed. They were compared with a group of patients transplanted at the same center for other causes of ESRD.

RESULTS

41 patients with kidney transplant due to SLE and 89 transplanted due to other causes of ESRD were registered. Graft loss occurred in 12 (29.26%) patients with LN and 34 (38.2%) patients in the comparison group (p = .428). Only one case (4.8%) presented reactivation of the LN in the graft, without graft loss. Median graft survival was 73.1 months in the LN group and 66.3 months in the comparison group (p = .221). A total of 8 (19.5%) patients with LN and 11 (12.4%) without LN died (p = .42), with infections being the main cause in both groups. There were no statistically significant differences between groups in graft and patient survival. In a sub-analysis of 28 patients with LN with aPL study, 4 thrombotic events were observed, in 3 different patients, in the aPL-positive group. There were no statistically significant differences in terms of causes of graft loss and graft survival (positive aFL 75.7 months vs negative aFL 72.7 months, p= .96). There were also no differences in mortality between the groups (p = .61).

CONCLUSION

Patients transplanted for LN did not differ from the control population in terms of graft and patient survival. Infections were the main cause of death, so prophylaxis and vaccination continue to be a fundamental pillar in the prevention of infections in immunocompromised patients.

Outcome and Prognosis of Patients With Lupus Nephritis Submitted to Renal Transplantation

This stydy aimed to evaluate the epidemiological and clinical profile and outcome of patients with lupus nephritis (LN) submitted to renal transplantation. Retrospective cohort study based on the records of 35 LN patients submitted to renal transplantation at a single center in Brazil between July 1996 and May 2016. The Kaplan-Meier method was used to estimate 6-month, 1-year and 5-year graft survival. The sample included 38 transplantations (3 of which retransplantations). The mean age at the time of SLE diagnosis was 23.7 ± 9.0 years. Most patients were female (94.7%) and 68.4% were non-Caucasian. Twenty-two (57.9%) underwent renal biopsy prior to transplantation. The mean time from SLE diagnosis to transplantation was 10.3 ± 6.4 years. The mean pre-transplantation dialysis time was 3.8 ± 3.7 years. The grafts came from living related (n = 11) or deceased (n = 27) donors. Three (7.9%) patients experienced acute rejection in the first year. Graft and patient survival rates were, respectively, 97.1% and 100% at 6 months, 84.9% and 96.9% at 1 year, and 76.3% and 92.5% at 5 years. One (2.6%) patient had SLE recurrence. Venous thrombosis (p = 0.017) and antiphospholipid syndrome (APS) (p = 0.036) were more prevalent in patients with graft loss. In our cohort of LN patients submitted to renal transplantation, the 5-year survival rate was high, and APS was an important predictor of poor renal outcome (graft loss).

MHC class II polymorphism is associated with a canine SLE-related disease complex

Nova Scotia duck tolling retrievers are predisposed to a SLE-related disease complex including immune-mediated rheumatic disease (IMRD) and steroid-responsive meningitis-arteritis (SRMA). IMRD involves symptoms that resemble those seen in systemic autoimmune rheumatic diseases, such as systemic lupus erythematosus, SLE, or SLE-related diseases, in humans. This disease complex involves persistent lameness, stiffness, mainly after resting, and palpable pain from several joints of extremities. The majority of affected dogs display antinuclear autoantibody (ANA)-reactivity. SRMA is manifested in young dogs with high fever and neck stiffness and can be treated with corticosteroids. We have investigated the possible role of MHC class II as a genetic risk factor in IMRD and SRMA etiology. We performed sequence-based typing of the DLA-DRB1, -DQA1, and -DQB1 class II loci in a total of 176 dogs including 51 IMRD (33 ANA-positive), 49 SRMA cases, and 78 healthy controls (two dogs were both IMRD- and SRMA-affected). Homozygosity for the risk haplotype DRB1*00601/DQA1*005011/DQB1*02001 increased the risk for IMRD (OR = 4.9; ANA-positive IMRD: OR = 7.2) compared with all other genotypes. There was a general heterozygote advantage, homozygotes had OR = 4.4 (ANA-positive IMRD: OR = 8.9) compared with all heterozygotes. The risk haplotype contains the five amino acid epitope RARAA, known as the shared epitope for rheumatoid arthritis. No association was observed for SRMA. We conclude that DLA class II is a highly significant genetic risk factor for ANA-positive IMRD. The results indicate narrow diversity of DLA II haplotypes and identify an IMRD-related risk haplotype, which becomes highly significant in homozygous dogs.

Anti-mannose binding lectin antibodies in sera of Japanese patients with systemic lupus erythematosus

Mannose-binding lectin (MBL) is a key element in innate immunity with functions and structure similar to that of complement C1q. It has been reported that MBL deficiency is associated with occurrence of systemic lupus erythematosus (SLE). We hypothesized that anti-MBL antibodies, if present, would affect the occurrence or disease course of SLE, by reduction of serum MBL levels, interference of MBL functions, or binding to MBL deposited on various tissues. To address this hypothesis, we measured the concentration of anti-MBL antibodies in sera of 111 Japanese SLE patients and 113 healthy volunteers by enzyme immunoassay. The titres of anti-MBL antibodies in SLE patients were significantly higher than those in healthy controls. When the mean + 2 standard deviations of controls was set as the cut off point, individuals with titres of anti-MBL antibodies above this level were significantly more frequent in SLE patients (9 patients) than in controls (2 persons). One SLE patient had an extremely high titre of this antibody. No associations of titres of anti-MBL antibodies and (i) genotypes of MBL gene, (ii) concentrations of serum MBL, or (iii) disease characteristics of SLE, were apparent. Thus, we have confirmed that anti-MBL antibodies are indeed present in sera of some patients with SLE, but the significance of these autoantibodies in the pathogenesis of SLE remains unclear.

A susceptibility locus for human systemic lupus erythematosus (hSLE1) on chromosome 2q

To identify chromosomal regions containing susceptibility loci for systemic lupus erythematosus (SLE), we performed genome scans in families with multiple SLE patients from Iceland, a geographical and genetic isolate, and from Sweden. A number of chromosomal regions showed maximum lod scores (Z) indicating possible linkage to SLE in both the Icelandic and Swedish families. In the Icelandic families, five regions showed lod scores greater than 2.0, three of which (4p15-13, Z=3.20; 9p22, Z=2.27; 19q13, Z=2.06) are homologous to the murine regions containing the lmb2, sle2 and sle3 loci, respectively. The fourth region is located on 19p13 (D19S247, Z=2.58) and the fifth on 2q37 (D2S125, Z=2.06). Only two regions showed lod scores above 2.0 in the Swedish families: on chromosome 2q11 (D2S436, Z=2. 13) and 2q37 (D2S125, Z=2.18). The combination of both family sets gave a highly significant lod score at D2S125 of Z=4.24 in favor of linkage for 2q37. This region represents a new locus for SLE. Our results underscore the importance of studying well-defined populations for genetic analysis of complex diseases such as SLE.

X-chromosome inactivation in monozygotic twins with systemic lupus erythematosus

The hypothesis that a low concordance rate in monozygotic (MZ) twins with systemic lupus erythematosus (SLE) may be accounted for by differences in X-chromosome inactivation was examined. Five MZ twin pairs, four discordant and one concordant, were recruited, zygosity confirmed by DNA fingerprinting, and their pattern of X-chromosome inactivation in DNA samples prepared from peripheral blood and buccal cells were examined. X-chromosome inactivation was assessed by the methylation status of the CpG region near trinucleotide repeats in exon 1 of the androgen receptor gene on X-chromosome after digestion with the methylation-sensitive enzyme HpaII or HhaI and PCR amplification. X-chromosome inactivation patterns were found to be the same between affected and non-affected twins in all four discordant twin pairs, with random patterns in two pairs and skewed patterns in the others. The concordant twins demonstrated the same random patterns. X-chromosome inactivation was also examined from buccal smear DNA and shown to have the same pattern as that noted from peripheral blood DNA in one informative twin pair. Differences in X-chromosome inactivation patterns were not observed in these five MZ twin pairs. The results could not support the hypothesis that differences in X-chromosome inactivation is the mechanism accounting for the low concordance rate noted in MZ twins with SLE.

Renal vascular lesions in lupus nephritis

We retrospectively studied the prevalence, histologic features, clinical correlations, and long-term outcome of the intrarenal vascular lesions of lupus nephritis (LN) in a series of 169 renal biopsies performed between 1980 and 1994 in 132 patients with systemic lupus erythematosus. The most common vascular lesions were nonspecific sclerotic changes, found in 37% of the biopsies (24% if only the cases with moderate to severe changes are considered). The other common vascular lesions were "immunoglobulin microvascular casts," found in 24% of the biopsies. Vasculitis and thrombotic microangiopathy were rare lesions and were seen in only 4 (2.4%) and 1 (0.6%) cases, respectively. Isolated sclerotic vascular changes were present in biopsies from older patients with a longer duration of LN, compared with the group with no vascular lesions, and were associated with a significantly higher prevalence of hypertension. Overall, however, the long-term renal and patient survival of this group did not differ significantly from that of the patients without vascular changes. Immunoglobulin microvascular casts (IMCs) ("lupus vasculopathy") were characterized by the presence of immunoglobulin deposition within the glomerular capillaries and small arterioles. In the present study we extensively investigated the morphologic and immunologic features of this lesion. The lesions were notable for the absence of endothelial or parietal vascular lesions and of fibrin, platelets, and leukocytes, which indicates that thrombosis is not involved in the vascular obstruction. According to our data immunoglobulin precipitation in the microvasculature seems to play a central role in the pathogenesis of this lesion, which is why we propose the term "immunoglobulin microvascular casts." In general, IMCs were associated with the most severe and active forms of diffuse proliferative lupus nephritis (World Health Organization [WHO] class IV). However our data show that, in contrast to previous studies, the long-term outcome of patients with IMCs is not worse than that of other patients with class IV LN. It may even be somewhat better, suggesting that this type of lesion may reverse with immunosuppressive therapy. In addition, we did not find any association between the presence of IMCs and the lupus anticoagulant, IgG anticardiolipin antibodies, or extrarenal vascular manifestations. Concerning vasculitis and thrombotic microangiopathy, our results confirm that their occurrence is quite rare in-lupus nephritis. The outcome of our 4 patients with vasculitis was not particularly poor, which could be related to early and/or aggressive treatment. Taken as a whole, our data confirm that the presence of active and severe forms of diffuse proliferative LN (WHO class IV) carries a worse prognosis compared with the other forms of LN. In our study, and in agreement with previous reports (23), the long-term renal survival of patients with class IV LN was significantly worse than that of patients with other forms of LN, with a 10-year renal survival of 70% compared with 85%, respectively. However our data do not support the conclusions of some previous studies that the presence of intrarenal vascular lesions is a marker of poor renal prognosis in lupus nephritis. More precisely, our data show that the somewhat poorer renal outcome observed in patients with IMCs is related to the fact that in most cases these lesions are associated with class IV lupus nephritis, and not related to the presence of the vascular lesion per se.

TNF microsatellite a2, b3 and d2 alleles are associated with systemic lupus erythematosus

We have investigated TNF microsatellite polymorphisms in SLE and their association with both HLA class II alleles and disease expression. A total of 91 Caucasoid SLE and 109 matched Caucasoid controls were recruited for this study. TNF microsatellites a, b and d were typed using fluorescent based semi-automated gene scanning. TNF a2, b3 and d2 allele frequencies were significantly increased in the SLE group compared to controls. These alleles were found to be part of an extended HLA-DRB1*0301 haplotype and have previously been associated with high TNF-alpha production. When the SLE group was analyzed according to presentation of certain clinical features, photosensitivity and Raynaud's phenomenon, the frequency of these alleles (TNF a2, b3 and d2) were also significantly increased. No significant increase in the allele frequencies of TNF a2, b3 and d2 was demonstrated in the group of patients with renal involvement. These data suggest that TNF microsatellite alleles are not independent of HLA associations in SLE and may be important in the expression of certain clinical features in SLE.

Mannose-binding protein gene polymorphism in systemic lupus erythematosus

OBJECTIVE

To determine whether an allelic form of mannose-binding protein (MBP) incapable of activating complement is associated with susceptibility to systemic lupus erythematosus (SLE).

METHODS

MBP allele frequencies were determined by amplification refractory mutation system-polymerase chain reaction in 102 white SLE patients and 136 controls.

RESULTS

The MBP allele that is unable to activate complement was present in 42 SLE patients (41%) and in 41 controls (30%) (P = 0.08, odds ratio [OR] = 1.6, 95% confidence interval [95% CI] 1.0-2.8). The gene frequency of this allele was 0.25 in SLE patients and 0.19 in controls (P = 0.08, OR = 1.5, 95% CI 1.0-2.3).

CONCLUSION

Our results suggest that this allele of the MBP gene represents a minor risk factor for SLE.

HLA-DP does not contribute towards susceptibility to systemic lupus erythematosus

OBJECTIVES

To determine whether HLA-DP genes are involved in determining susceptibility to systemic lupus erythematosus (SLE).

METHODS

HLA-DPA1 and DPB1 genes were amplified by PCR of DNA samples from a panel of patients with SLE and normal controls. Amplified DNA was blotted on to nylon filters and probed with sequence-specific oligonucleotide (SSO) probes.

RESULTS

No DPA1 or DPB1 allele was significantly associated with SLE, or with any immunological or clinical subset of SLE. Evidence was found for only limited linkage disequilibrium between HLA-DP and HLA-DQ/DR variants, and none between HLA-DP and the TAP2 gene.

CONCLUSIONS

These data indicate that HLA-DP genes do not contribute towards determining susceptibility to SLE.

Polymorphisms of the TAP2 transporter gene in systemic lupus erythematosus

OBJECTIVES

To determine whether the TAP2 transporter gene, which lies between HLA-DP and HLA-DQ, is involved in determining susceptibility to systemic lupus erythematosus (SLE).

METHODS

TAP2 types were determined by ARMS-PCR in 89 white patients with SLE and 156 control subjects.

RESULTS

No particular TAP2 dimorphism or allele was associated with SLE or with any clinical/immunological subgroup of SLE. Furthermore, there was no evidence for significant linkage disequilibrium between TAP2 and HLA-DQ/DR in SLE.

CONCLUSIONS

These data suggest that TAP2 is not a disease susceptibility gene for SLE and that the disease-predisposing haplotypes do not extend as far as TAP2. This indicates that any HLA-DP association with SLE must be independent of other class II (DQ/DR) associations.

Multiple clinical and biological autoimmune manifestations in 50 workers after occupational exposure to silica

OBJECTIVES

A self referred group of four workers from a factory producing scouring powder with a high silica content showed a surprisingly high number of features compatible with a connective tissue disease. Further subjects working at the same factory were subsequently studied to evaluate the relation between this exposure and the development of autoimmune processes.

METHODS

A total of 50 subjects (44 women, six men; mean (SD) age 43.7 (5.5) years; mean duration of employment 6.1 years) underwent a prospective study including clinical history and physical examination, an immunobiological study, HLA typing, radiological and functional oesophageal and respiratory examination, ophthalmological examination, and isotopic testing of salivary glands.

RESULTS

Symptoms of a systemic illness were present in 32 (64%) subjects: six with Sjögren's syndrome; five with the criteria for systemic sclerosis; three with systemic lupus erythematosus (SLE); five with an 'overlap syndrome'; and 13 with undifferentiated findings not meeting the criteria for a defined disease. Antinuclear antibodies were present in 36 (72%) subjects; four had antibodies to native DNA, including two subjects with SLE, one with systemic sclerosis associated with secondary Sjögren's syndrome, and one with overlap syndrome. Anticentromere antibodies were not detected. The frequency of HLA-DR3 was increased in the clinically affected subjects, but did not reach statistical significance.

CONCLUSIONS

This descriptive study emphasises the high probability of workers occupationally exposed to silica developing a multiple spectrum of clinical and serological autoimmune manifestations.

Analysis of clinical and laboratory profile in Indian childhood systemic lupus erythematosus and its comparison with SLE in adults

Data on the clinical and laboratory profiles of 83 children with SLE have been analysed and compared with data on 187 adults with the disease. The clinical features of childhood SLE are similar to those seen in adults, although clinical and laboratory parameters reflect propensity to a more severe form of the disease in the juvenile age group. However, in comparison to descriptions of childhood lupus from developed countries, in India the female-to-male ratio in this age group parallels that in adults. Renal involvement is noted to be more common, whereas gastro-intestinal and haematological abnormalities are less common. Interestingly, leucopenia, lymphopenia and nephritic type of renal involvement are commonly seen in boys with SLE, but these features are non-existent in men.

Diversity and pattern of inheritance of autoantibodies in families with multiple cases of systemic lupus erythematosus

The pattern of inheritance of autoantibodies in eight families chosen from a pool of 110 families of patients with systemic lupus erythematosus (SLE) is described. In all the eight families at least two members were already affected by SLE. In total, 19 patients and 43 first degree relatives were examined. The inheritance of a large set of antinuclear antibodies (for example, DNA, Sm, RNP, Ro, La, histones) and 16/6 idiotype seemed to be related to some unknown genetic factors but not related to HLA. The presence of numerous antinuclear autoantibodies in the serum of a subject was not necessarily associated with overt disease. The incidence of the 16/6 idiotype among patients and their relatives was low. It is not yet clear whether the 'autoantibody burden' is greater in families with multiple cases of SLE than in families with single cases.

The contribution of non-MHC genes to susceptibility to autoimmune diseases

Genetic studies of experimental models of autoimmune diseases, including systemic lupus-like syndromes and organ-specific autoimmunity, provide major information on genetic control of autoimmune diseases. In addition to genes known to be linked to the major histocompatibility complex (MHC), these studies point to multiple genes located outside the MHC that influence the onset and the progression of autoimmune diseases. Identification of these genes and of their interrelationships is now a major task that will be facilitated by recent progress in molecular biology and gene mapping. Among candidate genes, antigen-receptor genes (i.e., immunoglobulin- and T-cell receptor genes) most likely contribute an important part of the autoimmune susceptibility in several of these animal models. Available linkage data suggest a similar involvement of these antigen-receptor genes in several human autoimmune diseases. In addition to a better understanding of pathogenic mechanisms associated with autoimmunity, the knowledge of these disease-predisposing genes is expected to permit a better classification of often complex syndromes as well as the design of new treatments.

Stress proteins, autoimmunity, and autoimmune disease

At birth, the immune system is biased toward recognition of microbial antigens in order to protect the host from infection. Recent data suggest that an important initial line of defense in this regard involves autologous stress proteins, especially conserved peptides of hsp60, which are presented to T cells bearing gamma delta receptors by relatively nonpolymorphic class lb molecules. Natural antibodies may represent a parallel B cell mechanism. Through an evolving process of "physiological" autoreactivity and selection by immunodominant stress proteins common to all prokaryotes, B and T cell repertoires expand during life to meet the continuing challenge of infection. Because stress proteins of bacteria are homologous with stress proteins of the host, there exists in genetically susceptible individuals a constant risk of autoimmune disease due to failure of mechanisms for self-nonself discrimination. That stress proteins actually play a role in autoimmune processes is supported by a growing body of evidence which, collectively, suggests that autoreactivity in chronic inflammatory arthritis involves, at least initially, gamma delta cells which recognize epitopes of the stress protein hsp60. Alternate mechanisms for T cell stimulation by stress proteins undoubtedly also exist, e.g., molecular mimicry of the DR beta third hypervariable region susceptibility locus for rheumatoid arthritis by a DnaJ stress protein epitope in gram-negative bacteria. While there still is confusion with respect to the most relevant stress protein epitopes, a central role for stress proteins in the etiology of arthritis appears likely. Furthermore, insight derived from the work thus far in adjuvant-induced arthritis already is stimulating analyses of related phenomena in autoimmune diseases other than those involving joints. Only limited data are available in the area of humoral autoimmunity to stress proteins. Autoantibodies to a number of stress proteins have been identified in SLE and rheumatoid arthritis, but their pathogenetic significance remains to be established. Nevertheless, the capacity of certain stress proteins to bind to multiple proteins in the nucleus and cytoplasm both physiologically and during stress or injury to cells, suggests that stress proteins may be important elements in the "immunogenic particle" concept of the origin of antinuclear and other autoantibodies. In short, this fascinating group of proteins, so mysterious only a few years ago, has impelled truly extraordinary new lines of investigation into the nature of autoimmunity and autoimmune disease.

Absence of DRw15/3 and of DRw15/7 heterozygotes in Caucasian patients with systemic lupus erythematosus

Polymorphic MHC class II molecules determine immune responsiveness towards pathogens and also contribute to susceptibility or resistance to a number of different autoimmune diseases, including systemic lupus erythematosus (SLE). The HLA-DR and -DQ alleles of 52 patients with SLE were analyzed by serology and, for 42 patients, HLA-DRB1, -B3 and DQB1 allelic polymorphism was determined by oligotyping on PCR-amplified DNA. While we confirm the increase of DR3 (44.2% versus 16% in controls; p less than 0.001) reported by others, we observed a complete absence of DRw15(2)/DR3 and DRw15(2)/DR7 heterozygotes among Caucasian patients. Moreover HLA-DQB1 oligotyping revealed the absence of DQB1*0602/0201 heterozygotes in our panel of Caucasoid SLE patients. Since both DR3 and DR7 haplotypes share the same DQB1*0201-encoded DQ beta chain, and since DRw15 is known to be in linkage disequilibrium with DQA1*0102, it can be predicted that DQA1*0102/DQB1*0201 combinations are absent in Caucasian patients. We therefore propose that a DQA1*0201/DQB1*0201-encoded HLA-DQ trans-dimer formed in these heterozygotes might function as a suppressor-inducer molecule that confers resistance against SLE.

The origin of autoantibodies

Autoimmune diseases are characterized by the appearance of autoantibodies (autoAb) which may participate in their pathogenesis, but autoAb have also been found in normals with a variety of other conditions. The production of hybridomas from lymphocytes of unimmunized normal mice and healthy humans and analysis of the monoclonal autoAb (m-autoAb) obtained, showed that many had polyspecific autoAb reactivity, binding to many seemingly unrelated self-antigens, or to several organs. Most m-autoAb were of the IgM class and shared a common cross-reactive idiotype (CRI). Low levels of Ab with similar binding pattern and idiotype are continuously represented in the serum of mice and humans who have no evidence of autoimmune or other disease. Very similar Ab appear in autoimmune diseases. Studies of m-autoAb derived from lupus-prone mice and from patients with systemic lupus erythematosus (SLE) and other autoimmune diseases also revealed polyspecific binding, IgM isotype and CRI. Moreover, these CRI, which were almost identical with the idiotypes of natural autoAb in normals, may identify a group of pathogenic Ab in the lupus mice and SLE patients. Since the data clearly suggest that lymphocytes that make autoAb are common and are part of the normal B cell repertoire coded by widely dispersed germline genes, there remain the basic problems of the function of these autoAb in health, as well as the question of their regulation and activation in vivo. Several postulated functions and immunoregulatory mechanisms are discussed and the possible role of certain factors, especially viruses, in enhancing autoAb production and autoimmunity, is assessed.

Susceptibility genetics of systemic lupus erythematosus

The etiology of systemic lupus erythematosus (SLE) is determined in part by genetic factors which influence susceptibility to the disease. These factors presumably have a major role in determining the clinical and laboratory manifestations of SLE. Certain newer observations which may pertain to an understanding of the genetic basis of SLE will be critically reviewed in this chapter. These observations are based on advances in the analysis of human SLE and the increased knowledge provided by various murine models of human autoimmune processes. However, the specific genes involved and the mechanisms by which they exert their effect are at present still unknown. Special attention will be given newer insights into the role of genes of the major histocompatibility complex (MHC) and their relationship to the genes encoding the T cell antigen receptor. The role of classic immunoglobulin genes as well as more complex mechanisms involving preferential maternal or paternal genetic effects are also discussed. The contribution of genes encoding complement and complement receptors toward the expression of the disease state are discussed in brief.

[Acute systemic lupus erythematosus after thymectomy for myasthenia. Sequential study of lymphocyte subpopulations]

A 35 year-old woman developed severe systemic lupus erythematosus 9 years after thymectomy for myasthenia gravis. "Seric Thymic Factor" (STF) was low; T helpers subset, T helpers/T suppressors ratio and to a lesser extent T suppressors subset were decreased. Suppressor cell function investigated by Concanavaline A lymphocyte reactivity was low. Under cyclophosphamide, plasmapheresis and steroids all clinical and biological symptoms improved but STF remained low; T helpers, T suppressors subsets and T helpers/T suppressors ratio increased but did not reach the normal range. Statistical and immunological arguments suggest that the association between systemic lupus erythematosus and myasthenia gravis did not occur only by chance. Moreover, thymectomy might have played a role by decreasing the number and function of some subpopulations of lymphocytes.

Association of susceptibility to certain hematopoietic malignancies with the presence of Ia allodeterminants distinct from the DR series; utility of monoclonal antibody reagents

The Ia antigen allospecificities of individuals with either B type chronic lymphocytic leukemia or hairy cell leukemia resembled one another and differed significantly from those of a control population. In contrast, the Ia alloantigens of individuals with non-Hodgkin's lymphoma were distinctly different from those of the leukemic group but differed little from the control group. A monoclonal antibody, IVD12, directed to an MB3-like determinant reacted with the greatest proportion of the leukemic individuals and yielded the highest positive relative risk. A lower degree of positive association was found with the presence of the MT2 determinant. In contrast, the low observed frequency of the MT1/MB1 determinant among leukemic individuals was associated with the most significant negative relative risk. The relative risk associated with the presence of DR5 was positive, while among patients with chronic lymphocytic leukemia the relative risk associated with DR2 was negative. Among patients with Hodgkin's Disease the relative risk associated with the presence of DR5 was significantly increased.