Population and family studies of three disease-related polymorphic genes in systemic lupus erythematosus

The contribution to systemic lupus erythematosus (SLE) of three lupus-associated polymorphisms (involving the C4A2 complement component, Humhv3005 and the T cell antigen receptor alpha chain gene) are investigated in 81 individuals from 14 multiplex SLE families, 41 unrelated lupus patients, and 88 unrelated healthy controls. The results show a strong association between C4A deletion and SLE in these families. While the current study confirms the previously reported association between hv3005 deletion and sporadic SLE, the study fails to support this association in familial SLE patients. Moreover, no correlation is detected between the occurrence of hv3005 deletion and C4A null alleles in lupus patients, suggesting that the effects of these genetic polymorphisms on predisposition to lupus are independent. The previously reported lupus-associated T cell receptor (TCR) alpha chain polymorphism is not detected in any of the individuals studied here. The combined data suggest that C4A null alleles predispose strongly to development of lupus, whereas the influence of hv3005 deletion is relatively weak. The results also suggest that contributions of weak susceptibility genes such as hv3005 to disease predisposition may be obscured by the effects of stronger genetic factors and thus need to be examined in patients lacking these factors.

Immunochemical and flow cytometric analysis of androgen receptor expression in thymocytes

A variety of evidence suggests that the cells of the immune system are targets for the actions of gonadal steroids. Experiments in both normal animals and in autoimmune disease models have established that androgens exert immunomodulatory effects at the level of the thymus. We have attempted to define precisely the potential target cells for androgen action in the thymus using recently developed antibodies to the androgen receptor. We report here that these antibodies reveal AR expression in all classes of thymocytes defined by surface markers CD4 and CD8. The highest levels of AR expression were observed in the CD4-CD8+ and CD4-CD8- subsets that include the most immature cells. These experiments establish that thymocytes are potential targets for direct actions of androgens. The data further suggest AR expression in thymocytes may be developmentally regulated in these cells, and that androgen effects early in the process of thymocyte selection may contribute to the sexual dimorphism of immune responsiveness.

Castration alters peripheral immune function in normal male mice

While it is generally recognized that females show enhanced cell-mediated and antibody responses to antigenic stimulation, the physiological basis for this observed sexual dimorphism of the immune response is not well understood. We report here studies on the effects of androgen deficiency on the peripheral immune system. Intact male mice were compared to animals castrated 3-4 months previously. Phenotypic characterization of thymocyte and lymphocyte subpopulations was carried out using dual-colour flow cytometry. In vitro production by spleen cells of interleukin-2 (IL-2), IL-4 and interferon-gamma (IFN-gamma), and levels of total immunoglobulin and autoreactive antibodies was measured by specific immunoassays. In addition to thymic hypertrophy, castrated animals showed significant splenic enlargement, which was largely owing to expansion of the B-cell population. The castrated spleens contained relatively fewer mature T cells than intact controls (P < or = 0.001), but culture supernatants from these spleen cells contained higher levels of IL-2 and IFN-gamma than control cultures (P < 0.04). Levels of in vitro antibody synthesis (IgM, IgG, IgA) were not higher in castrated animals compared to controls, but the castrate spleen cell cultures showed increased levels of production of two autoreactive antibodies, anti-IgG (rheumatoid factor) and anti-thyroglobulin. These data suggest that androgen deprivation results in a relative decrease in the number of mature peripheral T cells, but those which reach the spleen have functional characteristics suggestive of enhanced activation. Dysregulation in the B-cell compartment may be the result of altered effects of T-cell-mediated control.

Use of magnetic resonance imaging and P-31 magnetic resonance spectroscopy to detect and quantify muscle dysfunction in the amyopathic and myopathic variants of dermatomyositis

OBJECTIVE

To investigate the use of magnetic resonance imaging (MRI) and P-31 magnetic resonance spectroscopy (MRS) in characterizing the metabolic and functional status of muscles in patients with amyopathic dermatomyositis (DM) and to compare the findings with those in patients with classic myopathic DM.

METHODS

Nine patients with amyopathic DM, 11 patients with myopathic DM, and 11 normal individuals were studied. MRI images of thigh muscles were obtained, and T1 and T2 relaxation times were calculated. Biochemical status was quantitated with P-31 MRS, by determining concentrations of phosphate metabolites during rest and exercise.

RESULTS

Patients with amyopathic DM showed no muscle inflammation, and MRS data obtained during rest were normal. During exercise at 25% and 50% maximum voluntary contractile force, the MRS data revealed significant differences between amyopathic DM patients and control subjects indicating inefficient metabolism. In contrast, muscles of patients with myopathic DM showed inflammation and metabolic abnormalities even during rest.

CONCLUSION

Metabolic deficiencies in patients with amyopathic DM were unmasked by exercise, suggesting that the 2 DM syndromes may share muscle abnormalities. MRI/MRS may be useful in diagnosis and optimization of treatment.

Associations of IgA and IgA-rheumatoid factor with disease features in patients with rheumatoid arthritis

In previous studies we have shown that levels of IgM-rheumatoid factor (RF) in plasma and peripheral blood mononuclear cell supernatants are correlated with disease activity and response to second-line therapy in patients with rheumatoid arthritis (RA). The present studies were designed to examine whether IgA-RF levels are also correlated with clinical features of this disease. Two groups of RA patients were studied. Group I consisted of 87 patients in whom extensive clinical data had been collected. Group II included nine patients beginning treatment with gold or methotrexate who were studied during the first year of therapy. Measurement of IgM, IgA, IgM-RF and IgA-RF in culture supernatants and plasma was done by an ELISA method. These data were examined for correlations with clinical and laboratory features. Levels of IgA-RF in supernatants and plasma were found not to be correlated with disease features in the cross-sectional analysis of Group I patients, while IgM-RF and total IgA levels did show significant clinical correlation. Treatment of Group II patients with gold or methotrexate was associated with significant decreases in plasma levels of total IgA and IgM-RF as well as a small but statistically significant decrease in plasma IgA-RF. Plasma levels of total IgM were not altered during therapy. These findings suggest that production of IgA but not IgA-RF is correlated with disease status in patients with RA.

Vascular permeability factor/endothelial growth factor (VPF/VEGF): accumulation and expression in human synovial fluids and rheumatoid synovial tissue

Vascular permeability factor (VPF, also known as vascular endothelial growth factor or VEGF), is a potent microvascular permeability enhancing cytokine and a selective mitogen for endothelial cells. It has been implicated in tumor angiogenesis and ascites fluid accumulation. Since development of the destructive synovial pannus in rheumatoid arthritis (RA) is associated with changes in vascular permeability (synovial fluid accumulation), synovial cell hyperplasia, and angiogenesis, we examined synovial fluids (SFs) and joint tissue for the expression and local accumulation of VPF/VEGF. VPF/VEGF was detected in all of 21 synovial fluids examined and when measured by an immunofluorimetric assay, ranged from 6.9 to 180.5 pM. These levels are biologically significant, since < 1 pM VPF/VEGF can elicit responses from its target cells, endothelial cells. Levels of VPF/VEGF were highest in rheumatoid arthritis fluids (n = 10), with a mean value (+/- SEM) of 59.1 +/- 18.0 pM, vs. 21.4 +/- 2.3 pM for 11 SFs from patients with other forms of arthritis (p = 0.042). In situ hybridization studies that were performed on joint tissues from patients with active RA revealed that synovial lining macrophages strongly expressed VPF/VEGF mRNA, and that microvascular endothelial cells of nearby blood vessels strongly expressed mRNA for the VPF/VEGF receptors, flt-1 and KDR. Immunohistochemistry performed on inflamed rheumatoid synovial tissue revealed that the VPF/VEGF peptide was localized to macrophages within inflamed synovium, as well as to microvascular endothelium, its putative target in the tissue. Together, these findings indicate that VPF/VEGF may have an important role in the pathogenesis of RA.

Magnetic resonance imaging and P-31 magnetic resonance spectroscopy provide unique quantitative data useful in the longitudinal management of patients with dermatomyositis

OBJECTIVE

To evaluate the utility of magnetic resonance imaging (MRI) and P-31 magnetic resonance spectroscopy (MRS) in the longitudinal management of patients with dermatomyositis (DM).

METHODS

The study group consisted of 11 patients, including 3 children, all of whom had a clinical diagnosis of DM. A control group of 8 subjects was studied simultaneously. MRI included images as well as calculations of T1 and T2 relaxation times. The P-31 MRS protocol evaluated metabolic status (i.e., inorganic phosphate/phosphocreatine ratios and phosphocreatine and ATP levels) during rest, exercise, and recovery.

RESULTS

T2-weighted images of the thigh muscles showed inflammation even when serum creatine phosphokinase levels were in the normal range. Metabolic abnormalities, which were accentuated with exercise, were found in 10 patients. In some individuals, bioenergetic defects preceded other changes and persisted after resolution of inflammation. In general, clinical impressions correlated with MRI/MRS data.

CONCLUSION

MRI and MRS provide unique data which are quantitative and which cannot be obtained from routine laboratory tests. These MR evaluations appear to be of value in assessing the status of DM patients during treatment with steroids and immunosuppressive drugs.

Anti-centromere antibodies (ACA) in systemic sclerosis patients and their relatives: a serological and HLA study

Autoantibody reactivity to centromere proteins CENP-A, CENP-B and CENP-C was examined in 58 patients with systemic sclerosis (SSc), 218 first degree relatives and 22 spouses. HLA class II typing for HLA-DRB1 and HLA-DQA1 was performed by restriction fragment length polymorphism (RFLP) analysis in 50 families, and HLA-DRB1, HLA-DQA1 and HLA-DQB1 typing was performed by olignucleotide typing in 44 families. Eleven probands and two relatives had ACA. The two relatives with ACA also had SSc. One relative was an identical twin sister of a proband with ACA and the other relative was a sister of a proband with ACA. All ACA-positive probands and relatives were female, and all recognized CENP-A, CENP-B and CENP-C. The presence of at least one HLA-DQB1 allele not coding for leucine at position 26 of the first domain appeared necessary, although not sufficient for the generation of ACA. Therefore within SSc families ACA is strongly associated with female gender and disease phenotype, and is at least in part genetically determined.

Induction of immature thymocyte proliferation after castration of normal male mice

The physiological basis and immunological significance of thymic enlargement in castrate male animals is not known. We used normal male C57 Bl/6 mice to examine the contribution of in situ thymocyte proliferation to castration-induced enlargement of the thymus. Animals castrated at 8-10 weeks of age were compared to normal intact males. Thymocytes were examined 4-120 days after castration using flow cytometry to determine DNA content and thus the number of cells in active phases of the cell cycle. These properties were examined in unseparated thymocytes and in phenotypic subpopulations defined by expression of CD3, CD4, and CD8. For thymocytes obtained from intact control glands, a mean of 11.0 +/- 1.0% were in active phases of the cell cycle. The percentage of cycling thymocytes was increased to a mean of 22.5 +/- 1.9% in the week after castration (P < 0.001). This change occurred in the absence of significant thymic enlargement. At 8-10 days after castration, thymic weight increased abruptly to a new steady state which was double that of intact controls (78.0 +/- 4.1 vs. 39.1 +/- 2.6 mg; P < 0.001). In these enlarged glands, only 9.9 +/- 0.8% of cells were cycling, which was not significantly different than controls (P > 0.3). Proliferating cells identified in fixed thymus tissue sections after in vivo administration of bromodeoxyuridine were located in the subcapsular cortex and medulla. Analyses of thymocyte subpopulations indicated that most cycling cells had immature phenotypes (CD4+CD8+, CD4-CD8+, and CD3lo or CD3-). Castrate glands studied in the steady state period 8-120 days after surgery contained significantly fewer CD3+ cells than intact controls (P < or = 0.045). The findings suggest an intrathymic role for androgens in affecting generation of the mature T cell repertoire.

Variability of immunologic and clinical features in patients with rheumatoid arthritis studied over 24 hours

Disease activity measures in patients with rheumatoid arthritis (RA) are influenced by many factors. Bedrest has been long recognized to effect decreased disease activity. In addition, most patients note maximal levels of pain and stiffness in the early morning hours with improvement in the afternoon. Cytokines and hormones with circadian rhythms may also contribute to variability in disease status during the day. Our purpose was to investigate variability of clinical and immunologic measures over a 24-h period of hospitalization in patients with RA. Production of rheumatoid factors and immunoglobulins, joint counts and questionnaire evaluations were measured 3 to 6 times over a 24-h period of hospitalization in 10 patients with RA who were not receiving steroids or second line drugs. Total joint counts were significantly decreased as soon as 4 h after admission, and continued to decrease during the 24-h period of observation. Significant decreases in mononuclear cell proliferation and antibody synthesis were also observed. Our findings are consistent with the presence of decreased levels of immunostimulatory mediators in hospitalized patients especially during late afternoon or evening hours.

Testosterone induces expression of transforming growth factor-beta 1 in the murine thymus

Castration of adult male mice results in enlargement of the thymus and diminution of peripheral suppressor T cell function. Replacement therapy with physiologic doses of androgens reverses these phenomena. Although the mediators involved are unknown, these effects of androgens on the thymus and peripheral immune system are reminiscent of those reported for transforming growth factor-beta (TGF-beta 1). We examined expression of TGF-beta 1 mRNA and bioactive protein in thymuses from castrate and androgen-replaced animals. Steady-state levels of thymic TGF-beta 1 mRNA fell slightly after castration, but rose 2.3-fold after testosterone replacement. Bioactive TGF-beta 1 production by cultured thymic explants also fell following castration to approx. 50% of the levels observed in intact animals. Following 1 week of testosterone replacement in castrate animals, TGF-beta 1 bioactivity produced in culture was restored to levels indistinguishable from those observed with explants from intact animals. Reverse transcription/polymerase chain reaction amplification of RNA revealed that thymocytes are a source of the androgen-modulated TGF-beta 1. These results suggest that TGF-beta 1 may mediate effects of androgens on the immune system.

Effects of administration of an anti-CD5 plus immunoconjugate in rheumatoid arthritis. Results of two phase II studies. The CD5 Plus Rheumatoid Arthritis Investigators Group

OBJECTIVE

To evaluate the safety and activity of an immunoconjugate of ricin A chain and anti-CD5 monoclonal antibody (anti-CD5 IC), with and without concomitant methotrexate and/or azathioprine, in the treatment of rheumatoid arthritis (RA).

METHODS

Seventy-nine patients with active RA were enrolled in 2 prospective open-label protocols.

RESULTS

Using composite criteria, response rates were 50-68% at 1 month and 22-25% at 6 months. Transient depletion of CD3/CD5 T cells was observed on days 2 and 5 of treatment, with reconstitution on day 15 or day 29. Treatment-associated adverse effects were common but resolved rapidly without sequelae.

CONCLUSION

These findings suggest activity of anti-CD5 IC in active RA and warrant confirmation in a multicenter randomized study (currently underway).

In vivo T cell depletion in rheumatoid arthritis is associated with increased in vitro IgM-rheumatoid factor synthesis

T cell depletion has been demonstrated to have therapeutic potential in patients with rheumatoid arthritis and several agents which deplete or inactivate T cells are currently being evaluated in clinical trials. We treated six patients with active rheumatoid arthritis with one such agent, the murine IgG1 anti-CD5 immunoconjugate CD5 Plus, as part of a multicenter trial. Measurement of in vitro synthesis of IgM and IgM-rheumatoid factor by peripheral blood mononuclear cells obtained from patients before, during, and after treatment, was performed using enzyme-linked immunoassays. Subsets of T and B lymphocytes were measured by flow cytometry. Significant T cell depletion was observed on Days 2 and 5 during the treatment period and was associated with increased in vitro rheumatoid factor (RF) production on Days 5 and 8 in 4 of the 5 patients with significant pretreatment levels of RF synthesis. No apparent relationship to serum RF levels or clinical responses was noted. These results implicate a role for T cells in the control of IgM-RF production in patients with rheumatoid arthritis.

Schistosoma mansoni: mortality, pathophysiology, and susceptibility differences in male and female mice

In parallel studies of Schistosoma mansoni infections in male and female CBA/J mice, major sex-related differences are seen in the development of infection and disease. Upon equal subcutaneous exposures to 45 cercariae female mice present a more severe clinical course with consequent higher mortality than male mice. By 12 weeks of infection, more than 80% of female mice die, while less than 20% of infected males succumb to infection. This greater index of mortality is apparently due to the higher susceptibility of female mice to the development of adult worms. Exposed to 45 cercariae, virtually all females develop patent infections, but 8-34% of male mice do not do so. Also, the recovery rate of adult worms per cercariae from female mice is much higher than that from males, indicating that schistosomula are more successful in developing into adult worms in female mice. Additional studies indicate that this dichotomy of schistosomiasis in the sexes is not restricted to mice of the CBA/J strain, but also occurs in C57BL/6 and outbred CF1 strain mice.

Lymphocyte-derived adrenocorticotropin is insufficient to stimulate adrenal steroidogenesis in hypophysectomized rats

Cells of the immune system can produce and respond to peptide hormones associated with the endocrine system. However, the physiological significance of these endocrine-immune interactions is not known. It has been postulated that cells of the immune system, when stimulated with viruses that induce interferon-alpha, produce sufficient levels of ACTH to stimulate adrenal steroidogenesis and, thus, function as an auxiliary source of ACTH that may have a role in the response to stress. However, we have confirmed that levels of ACTH-related peptides produced by immunocompetent cells are far lower than those produced by the pituitary, raising questions about the ability of lymphocyte-derived ACTH to stimulate adrenal function. Furthermore, we have rigorously examined this issue using intact and hypophysectomized rats treated with Newcastle disease virus. Although high levels of interferon-alpha were produced by both intact and hypophysectomized rats, and the plasma corticosterone concentration increased dramatically in intact animals, corticosterone remained undetectable in hypophysectomized rats. The lack of a corticosterone response in these animals was not due to adrenal insensitivity to ACTH, as shown by a normal rise in corticosterone following Cosyntropin injection 8 h after hypophysectomy. The findings demonstrate that levels of ACTH produced by nonpituitary sources in response to viral infection are not sufficient to stimulate adrenal steroidogenesis.

Androgen deprivation induces phenotypic and functional changes in the thymus of adult male mice

The functional immunological consequences of thymic regeneration after castration were studied in adult male C57Bl/6 mice. Phenotypic profiles of thymocytes present in the enlarged thymuses of castrate animals demonstrated a significant decrease in the proportion of thymocytes positive for the suppressor/cytotoxic phenotype (CD4-CD8+; P = 0.005). Thymic enlargement in castrate animals was accompanied by increased capacity of thymocytes to incorporate thymidine in response to Concanavalin A in vitro. Spleens from castrate mice also were enlarged, and in vitro generation of functional suppressor cells by splenocytes from castrate animals was decreased. Testosterone replacement resulted in thymic regression, with a shift toward expression of mature thymocyte phenotypes, a decrease in the double-positive phenotype (CD4+CD8+), and a relative predominance of the CD4-CD8+ suppressor/cytotoxic phenotype over the CD4+CD8- helper phenotype. Unstimulated thymidine incorporation by thymocytes from androgen-treated animals was decreased compared to controls (P = 0.050). Spleen size was not altered by androgen administration. These findings suggest that in the adult animal, changes in androgen status effect alterations in thymocyte phenotypic profiles and thymocyte function, with removal of androgens shifting the T cell balance toward the CD4 helper subset and administration of androgens changing the balance toward CD8 suppressor/cytotoxic T cell predominance.

HLA-DPB1*0301 is a major risk factor for rheumatoid factor-negative adult rheumatoid arthritis

HLA-DPB1 alleles were determined using the polymerase chain reaction and allele-specific oligonucleotide probes in Caucasoid patients with rheumatoid arthritis (RA) and in healthy controls. DPB1*0301 was found to be increased in seronegative patients (50.0% versus 10.8% in controls; relative risk = 8.3, P less than 0.0001). With our previous finding that DPB1*0301 is increased in seronegative children with polyarticular-onset arthritis, the results suggest a relationship between this disease and seronegative RA in adults.

IgM-rheumatoid factor and responses to second-line drugs in rheumatoid arthritis

We have examined the relationship between IgM-rheumatoid factor (RF) and responses to second-line drugs in patients with rheumatoid arthritis (RA). Patients with active RA who were beginning treatment with gold, methotrexate or both were studied. Clinical responses were assessed with ESR, joint count, grip strength and activities of daily living questionnaire scores. Production of IgM-RF by peripheral blood mononuclear cells in vitro and plasma levels of IgM-RF were measured by ELISA. Overall, 31 of 44 patients completing more than 6 months treatment improved including 10 treated with gold, 12 with MTX and 9 with both. Production of IgM-RF by peripheral blood mononuclear cells was decreased by 59% in patients who improved on treatment, but increased 2-fold in the unimproved group. Plasma levels of IgM-RF were decreased from 121 to 66 micrograms/ml in the improved group after 6 months of treatment, with similar decreases seen for each of the three treatments. In contrast, plasma IgM-RF levels in the unimproved group did not decrease until 1 year of treatment was completed. Nine patients converted to seronegativity, and all but one of these were in the improved group. The results suggest that IgM-RF is correlated with responses to second-line drug in RA patients.

Molecular basis of an autoantibody-associated restriction fragment length polymorphism that confers susceptibility to autoimmune diseases

Recently, combined serological and molecular studies of autoantibodies have revealed that these antibodies play an important role in the normal function of the immune system and in the development of the B cell repertoire. Accordingly, we hypothesized that a homozygous deletion of a critical autoantibody-associated Ig variable (V) gene may alter the immune system and thus predispose the host to autoimmune disorders. Initial experiments revealed several restriction fragment length polymorphisms (RFLP) of the Humhv3005 gene, that is likely to encode heavy chains of rheumatoid factors, and the closely related 1.9III gene. By probing EcoR1-digested DNA with the Humhv3005/P1 probe, we found that one of the four major hybridizing bands was missing in approximately 20% of patients with either rheumatoid arthritis or systemic lupus erythematosus, but only 2% of normal subjects. To delineate the genetic basis of this polymorphism, we have now employed the PCR to amplify and analyze hv3005, 1.9III, and homologous genes in individuals with characteristic RFLP genotypes. Our results indicate that the human Vh gene repertoire contains several hv3005- and 1.9III-like genes, and that a complete deletion of the hv3005-like genes is relatively restricted to a subset of autoimmune patients. These findings provide initial evidence for deletion of developmentally regulated autoreactive V genes in autoimmune diseases.

Immunogenetics of autoantibodies and autoimmune diseases

The genetic contribution to the development of autoimmune disease is most likely complex. Along with loci controlling histocompatibility antigens and T-cell receptor proteins, genes that encode autoreactive immunoglobulins may have an important role in the pathogenesis of rheumatoid arthritis and related autoimmune diseases. Although much previous work in this area has concentrated on human monoclonal paraproteins and autoimmune mouse strains, the studies reviewed here examine immunoglobulin genes in the normal human population and normal mouse strains as well as in patients with autoimmune disease. Taken together, these studies suggest that genetic control of the expression of autoimmunity in rheumatoid arthritis and related autoimmune disorders is complex and most likely involves multiple gene loci.

Transforming growth factor beta 1 (TGF-beta 1) induced neutrophil recruitment to synovial tissues: implications for TGF-beta-driven synovial inflammation and hyperplasia

We have studied the consequences of introducing human recombinant transforming growth factor beta 1 (hrTGF-beta 1) into synovial tissue of the rat, to begin to better understand the significance of the fact that biologically active TGF-beta is found in human arthritic synovial effusions. Within 4-6 h after the intra-articular injection of 1 microgram of hrTGF-beta 1 into rat knee joints, extensive recruitment of polymorphonuclear leukocytes (PMNs) was observed. Cytochemistry and high resolution histological techniques were used to quantitate the influx of PMNs, which peaked 6 h post-injection. In a Boyden chamber assay, hrTGF-beta 1 at 1-10 fg/ml elicited a chemotactic response from PMNs greater in magnitude than that evoked by FMLP, establishing that TGF-beta 1 is an effective chemotactic agent for PMNs in vitro as well as in vivo. That PMNs may represent an important source of TGF-beta in inflammatory infiltrates was strongly suggested by a demonstration that stored TGF-beta 1 was secreted during phorbol myristate acetate-stimulated degranulation in vitro. Acid/ethanol extracts of human PMNs assayed by ELISA contained an average of 355 ng of TGF/beta 1 per 10(9) cells potentially available for secretion during degranulation of PMNs. [3H]Thymidine incorporation in vivo and autoradiography of tissue sections revealed that widespread cell proliferation was triggered by TGF-beta 1 injection. Synovial lining cells and cells located deep within the subsynovial connective tissue were identified as sources of at least some of the new cells that contribute to TGF-beta 1-induced hyperplasia. Our results demonstrate that TGF-beta is capable of exerting pathogenic effects on synovial tissue and that PMNs may represent a significant source of the TGF-beta present in synovial effusions.

Studies of immunological function in mice with defective androgen action. Distinction between alterations in immune function due to hormonal insensitivity and alterations due to other genetic factors

The presence of androgen receptors in thymocytes and the well-described effects of exogenous androgens on thymus size suggest a role for androgenic hormones in thymocyte growth and maturation. Testicular feminization (Tfm/Y) mice which bear a heritable defect in the androgen receptor protein were studied to investigate how androgens might influence immune phenotype and function. These mice were compared to two types of controls; their Tabby/Y normal male littermates and male mice of the C57 Bl/6 strain from which the Tabby and Tfm mice were derived. Thymuses and spleens from Tfm/Y mice were larger than both types of controls. Phenotypic differences in thymocyte and splenocyte subpopulations identified by the T-cell markers CD3, CD4 and CD8 suggested that T-cell maturation was altered in the androgen-resistant animal. However, both Ta/Y and Tfm/Y were found to be high producers of interleukin-4 (IL-4) by both spleen and thymus cells, while cells from the C57 mice produced predominantly IL-2. These findings suggest that some immunological features of the Tfm/Y mouse may be related to its defect in androgen action, but that high levels of IL-4 production are probably related to other genetic changes in the C57 background.

Clinical correlations with serum C1q levels in patients with rheumatoid arthritis

Previous studies have suggested that serum C1q levels measured during the first 5 years of rheumatoid arthritis (RA) may be predictive of the extent of subsequent joint damage. To further evaluate the clinical significance of this marker in RA, levels of C1q were measured by radial immunodiffusion in serum samples from 107 well-characterized patients with RA. Mean levels of C1q were higher in patients with a disease duration less than or equal to 5 years (173 micrograms/ml) than in patients with a disease duration greater than 5 years (148 micrograms/ml) (P = 0.032). Serum C1q levels were correlated with total joint counts and activities of daily living scores, but no correlation was observed with erythrocyte sedimentation rates or with radiographic scores. The results suggest that C1q may be a useful early marker of disease activity in patients with RA.