Mitsuo Homma

Importance of increased urinary calcium excretion in the development of secondary hyperparathyroidism of patients under glucocorticoid therapy

Parathyroid function and calcium metabolism were studied in 44 patients under glucocorticoid therapy (steroid group) and in 25 control subjects. Nephrogenous cAMP and serum immunoreactive parathyroid hormone levels in the steroid group were significantly higher than those in control subjects (p less than 0.001). Nephrogenous cAMP in the steroid group correlated positively with prednisolone dosage (r = 0.424, p less than 0.01), and most patients who showed obvious elevations of nephrogenous cAMP had received over 10 mg/day of prednisolone for at least 2 mo. Fasting urinary calcium in the steroid group [166.1 +/- 78.5 (+/- SD) mg/g creatinine] was about 2 times greater than that in control subjects (74.1 +/- 35.6) (p less than 0.001). Fasting urinary calcium in control subjects correlated negatively with nephrogenous cAMP (r = -0.486, p less than 0.02). In contrast, these values in steroid group showed significant positive correlation (r = 0.631, p less than 0.001), suggesting that increased urinary calcium excretion is an important factor in the development of secondary hyperparathyroidism. Elevated nephrogenous cAMP and serum immunoreactive parathyroid hormone levels decreased after the administration of trichlormethiazide and/or 1 alpha hydroxy-vitamin D3. We conclude that increased urinary calcium excretion plays an important role in the development of secondary hyperparathyroidism in patients under glucocorticoid therapy and that the administration of thiazide and/or vitamin D could improve the secondary hyperparathyroidism caused by glucocorticoid therapy.

Autoantibody reactive with three classes of RNA polymerases in sera from patients with systemic sclerosis.

We have identified a novel autoantibody reactive with all three classes of RNA polymerases, well-characterized nuclear enzymes, in sera from patients with systemic sclerosis (SSc). After incubation with [35S]methionine-labeled HeLa cell extracts, 14 of 275 SSc sera immunoprecipitated 12 or 14 proteins with similar molecular weights as those of several subunit proteins of eukaryotic RNA polymerases I, II, and III. Purified IgG from these two types of sera inhibited RNA transcription catalyzed by RNA polymerases I, II, and III in vitro. Immunoblot analysis using RNA polymerase-enriched fraction showed that the majority of these sera reacted with 42- or 25-kD protein. Anti-RNA polymerase antibody was highly specific to SSc, especially to diffuse cutaneous SSc. Clinical features associated with this antibody included a high frequency of heart and kidney involvement and a poor survival rate at 5 yr after first visit. These findings indicate that the autoantibody to three classes of RNA polymerases is a new marker for a unique subset of diffuse cutaneous SSc.

Characteristics of anti-T-cell antibodies in systemic lupus erythematosus: Evidence for selective reactivity with normal suppressor cells defined by monoclonal antibodies☆

Abstract Monoclonal antibodies have been produced to multiple human T-cell surface antigens. While some of these antibodies define antigens represented on all peripheral T cells (T3), others are restricted in their reactivity to the human inducer T-cell subset (T4) or reciprocal cytotoxic/suppressor subset (T5/T8). In the present study, the relationship of naturally occurring anti-T-cell antibodies found in patients with systemic lupus erythematosus (SLE) to these T-cell subsets was examined. T cells were purified by Sephadex G-200 anti-F(ab′)2 affinity chromatography and E rosetting techniques and subsequently, inducer or suppressor subsets eliminated with T4 or T8 and rabbit complement. Utilizing indirect immunofluorescence on the Fluorescence Activated Cell Sorter (FACS), it was found that the anti-T-cell antibodies from 10 patients with active systemic lupus erythematosus (SLE) reacted with approximately 80% of the suppressor-enriched (T4−)subset. In contrast, they were virtually unreactive with inducer-enriched (T8−)subset. In reciprocal studies, anti-T-cell antibody-reactive T cells (SLE+) were eliminated with SLE sera and the residual T cells reacted with monoclonal antibodies on the FACS. These studies showed that the T4+ inducer population was increased after elimination of the SLE+ T-cell subset whereas the T5+ suppressor population was diminished. Moreover, in functional studies, it was shown that when the SLE+ T-cell subset was removed, there was significant enhancement of pokeweed mitogen (PWM)-driven immunoglobulin synthesis by autologous normal B lymphocytes. In addition, lysis of this same SLE+ subset resulted in an increase in native DNA-driven Ig synthesis by B lymphocytes from patients with inactive SLE. These studies demonstrate that the anti-T-cell antibodies found in patients with active SLE are selectively reactive with the human suppressor T-cell population as defined by monoclonal antibodies.

Altered function of suppressor T lymphocytes in patients with active systemic lupus erythematosus--in vitro immune response to autoantigen.

Abstract Immunological reactivity in patients with systemic lupus erythematosus (SLE) was assessed by in vitro stimulation of Ig synthesis by peripheral blood lymphocytes in response to native DNA (n-DNA). Lymphocytes from patients with active SLE synthesized significantly larger amounts of Ig when stimulated with n-DNA than did lymphocytes from patients with inactive SLE or from normal controls. Lymphocytes from patients with active SLE and from normal controls were cocultured in the presence of n-DNA. Ig synthesis by B lymphocytes from patients with active SLE stimulated with n-DNA was suppressed by T lymphocytes from normal controls, whereas Ig synthesis by B lymphocytes from normal controls stimulated with n-DNA increased when cocultured with T lymphocytes from active SLE. We further examined the effect of Con A pretreatment of T lymphocytes on Ig synthesis. Pretreated T lymphocytes from normal controls and patients with inactive SLE significantly suppressed both PWM-stimulated Ig synthesis by peripheral blood lymphocytes from normal controls and n-DNA-stimulated Ig synthesis by lymphocytes from patients with active SLE. Con A-pretreated T lymphocytes from patients with active SLE failed to suppress either PWM-stimulated Ig synthesis by lymphocytes from normal controls or n-DNA-stimulated Ig synthesis by lymphocytes from other patients with active SLE. These results suggest that suppressor T lymphocyte function is lost in patients with active SLE.

Mononuclear cells enhance prostaglandin E2 production of polymorphonuclear leukocytes via tumor necrosis factor α

To clarify the interactions between mononuclear cells and polymorphonuclear leukocytes, and to identify the cytokine(s) that mediate the interaction, the effects of a culture supernatant of LPS-stimulated mononuclear cells on production of arachidonic acid metabolites of polymorphonuclear cells were studied. The culture supernatant of LPS-stimulated mononuclear cells increased production of prostaglandin E2 of polymorphonuclear cells. TNF alpha, but not IL-1, IL-2, IL-6, or IFN gamma, enhanced the prostaglandin E2 production when added in vitro. Additionally, an anti-rTNF alpha monoclonal antibody inhibited the stimulating activity of the culture supernatants. TNF alpha, produced by mononuclear cells, appears to play an important role in the development of inflammation, such as rheumatoid arthritis, by enhancing the arachidonic acid metabolism of the polymorphonuclear cells.

In vitro TNP-specific antibody formation by peripheral lymphocytes from patients with systemic lupus erythematosus.

Immunological reactivity in patients with systemic lupus erythematosus (SLE) was assessed by investigating in vitro trinitrophenyl (TNP)‐specific antibody formation by peripheral lymphocytes. Peripheral lymphocytes from 16 patients with SLE were cultured with TNP conjugated with horse erythrocytes (TNP–HRBC) in the presence of 2‐mercaptoethanol. The hemolytic plaque assay was used to detect hapten (TNP)‐specific antibody‐forming cells. Peripheral lymphocytes from normal individuals failed to produce antibody to TNP, whereas SLE lymphocytes produced a significant number of plaque‐forming cells. Co‐culture experiments with SLE and normal lymphocytes suggested that patients with SLE have a defect in T lymphocytes, leading to abnormal antibody production.

A Case of Unusual SLE Related Syndrome Characterized by Erythema multiforme, Angioneurotic Edema, Marked Hypocomplementemia, and Clq Precipitins of the Low Molecular Weight Type

Our patient and those of Agnello et al. had identical clinical symptoms such as erythema multiforme, arthralgias and angioneurotic edema and both differed from systemic lupus erthematosus in several important points, i.e., in spite of marked hypocomplementemia the nephropathy is not prominent and it needs high-dose steroids to eliminate the clinical and serological abnormalities. In addition to the features reported by Agnello et al. we found increased viral antibody titers in our patients sera.

In vitro immune response of SLE lymphocytes. The mechanism involved in B-cell activation

Peripheral blood lymphocytes from 26 patients with systemic lupus erythematosus (SLE) and six normal individuals were tested for IgG synthesis in the presence or absence of PWM. Lymphocytes from patients with active SLE synthesized increased amounts of IgG in the absence of PWM and reduced amounts of IgG in the presence of PWM. Serum from patients with active SLE had an enhancing effect on the in vitro IgG synthesis of normal lymphocytes. The IgG or F(ab′)2 fractions of SLE serum retained the enhancing effect on in vitro IgG synthesis, and the enhancing activity was absorbed by human spleen cells. As little as 4 h of incubation with SLE serum was needed for the enhancing activity of normal lymphocytes. Treatment of B lymphocytes appeared to be of main importance for an increase in the in vitro IgG synthesis of SLE serum‐treated lymphocytes. These results suggest that anti‐B‐lymphocyte antibodies from patients with active SLE are responsible in part for the hyperactive response of SLE B lymphocytes.

Studies of Anti-lymphocyte Antibody of Patients with Active SLE.: I. Cause of Loss of Suppressor T-Lymphocyte Function

Effect or anti‐lymphocyte antibody or active systemic lupus erythematosus (SLE) on lymphocyte function was examined. Lymphocytes from normal individuals treated with anti‐lymphocyte antibody and complement exhibited marked inhibition of response to concanavalin A (Con A). while the response of lymphocytes to phytohaemagglutinin M (PHA‐M) and pokeweed mitogen (PWM) was slightly affected. In mixed lymphocyte culture response, both stimulator and responder tells were insensitive to anti‐lymphocyte antibody. Treatment of sensitized lymphocytes with anti‐lymphocyte amibody and complement caused a dose‐dependent suppression of blaslo‐genic response to purified protein derivatives (PPD). No effect, however, was noted on migration‐inhibitory factor (MlF)‐producing cells. In PWM‐driven Ig synthesis, T lymphocytes lacking the anti‐lymphocyte antibody‐reactive T‐cell subset enhanced PWM‐driven Ig synthesis of autologous B lymphocytes. Con‐A‐induced suppressor function of lymphocytes was abolished by the treatment with unti‐lymphocytc antibody and complement. The present study demonstrated that lymphocytes from normal individuals after treatment with anti‐lymphocyte antibody and complement showed similar immunological reactivities with lymphocytes from active SLE, indicating that those anti‐lymphocyte antibodies could play an important role in defective suppressor cell function.

Relationship between Autoantibodies and Clinical Parameters in Sjögren's Syndrome

Glandular function as estimated by salivary function scintigraphy and extraglandular manifestations were compared among 174 Sjögrens syndrome (SS) patients according to their anti-Ro/SSA, anti-La/SSB, and anti-U1RNP autoantibody status, to clarify the relationship between these autoantibodies and clinical parameters in SS. These antibodies were detected by RNA-immunoprecipitation. Anti-La/SSB or only anti-Ro/SSA antibody was common in 84 primary SS (P-SS) patients, whereas the frequency of only anti-U1RNP was high in 90 secondary SS (S-SS) patients, especially in those with systemic lupus erythematosus (SLE). Antibody-negativity was common in SS with rheumatoid arthritis and was also found in 33% of P-SS. In P-SS, salivary gland dysfunction and parotid swelling were severe in patients who had serological abnormalities with anti-Ro/SSA and with or without anti-La/SSB. They were mild in antibody-negative patients who had mild extraglandular symptoms and in patients with only anti-U1RNP antibody who had Raynauds phenomenon, pulmonary fibrosis, and later disease onset. P-SS patients positive for both anti-Ro/SSA and anti-U1RNP had SLE-like features. SS could be classified clinically according to these autoantibodies.