[A study of epidemiology and fetal effects of human parvovirus B19 infection]

The risk of human parvovirus B19(B19) infection in pregnant women, the relationship between B19 and early spontaneous abortion, and the pathogenesis of non-immune hydrops fetalis (NIHF) due to B19 infection were studied. 1) After the period of prevalence of erythema infectiosum(EI) between 1986 and 1987, the positive rate of anti B19 IgG antibody by sandwich ELISA in the sera from subjects aged 15-34 years old was 17-26%. This indicates that about 80% of pregnant women could be at the risk of B19 infection in future EI prevalence within ten years. 2) IgM antibody assayed by capture ELISA was positive in 1.4% of the sera from pregnant women during the period of EI prevalence. 3) B19 DNA could not be detected by in situ hybridization (ISH) in any chorionic tissues from 105 early spontaneous abortuses during the period. B19 infection could not be proven as one of the causes of early spontaneous abortion. 4) B19 DNA was localized by ISH in erythroblasts but not in myocardial cells of two fetuses out of 11 NIHF. Therefore, NIHF following B19 infection could take place due to anemia following B19 infection of erythroblasts and their destruction.

Prognostic significance of transforming growth factor-alpha in human esophageal carcinoma. Implication for the autocrine proliferation

BACKGROUND

The authors recently used immunostaining to demonstrate that patients with epidermal growth factor receptor (EGFR) overexpression have poor survival after surgery. However, the clinical significance of transforming growth factor (TGF)-alpha, one of the ligands of EGFR, has not been demonstrated in esophageal carcinoma.

METHODS

Immunohistochemical study for TGF-alpha and EGFR was performed on 57 esophageal squamous cell carcinomas using monoclonal antibodies.

RESULTS

TGF-alpha expression was positive in 35% of the tumors, and EGFR overexpression, defined as stronger staining in cancer cells than in normal epithelium, was positive in 43% of the tumors, according to the authors' arbitrary criteria. The incidence of TGF-alpha positivity was relatively higher in patients with the EGFR overexpression (EGFR+) than in the patients with non-overexpression (EGFR-). The survival rate was significantly lower in patients with TGF-alpha(+) than in those with TGF-alpha(-) (P < 0.01) and in patients with EGFR(+) than in patients with EGFR(-) (P < 0.01), respectively. Considering TGF-alpha and EGFR expression simultaneously, the survival rate of the patients with TGF-alpha(+)/EGFR(+) tumors was the lowest of the four subgroups, with statistically significant differences noted. These relationships between the immunoreactivities and survival curves were observed in the analysis within patients with node-positive disease. In addition, a multivariate statistical analysis demonstrated that TGF-alpha was the only significant variable, whereas EGFR and nodal status provided no additional information regarding postoperative survival.

CONCLUSION

The results presented suggest that TGF-alpha may act as an autocrine growth factor through hyperproducing EGFR and that its expression and EGFR overexpression may prove useful as a valuable prognostic indicator for patients with esophageal carcinoma.

Usefulness of thallium-201 re-injection method for the evaluation of myocardial viability

Areas of the heart which are supposedly absent of myocardial viability due to persistent thallium defect in exercise thallium myocardial scintigraphy sometimes recover ventricular wall motion through coronary revascularization. To avoid such underestimation of myocardial viability, a "re-injection method" was developed. At the peak of supine ergometer exercise in 51 patients with coronary artery disease, 111 MBq thallium was injected. Conventional exercise and 3 h-delay images were then obtained using single photon emission computed tomography. Subsequently, 55 MBq thallium was injected and a re-injection image was obtained 1 h later. Each image was divided into 12 segments and compared by left ventriculography and coronary angiography. Redistribution was found in 36 patients (71%) on the delayed images and in 44 patients (86%) on either the delayed or the re-injection images (p < 0.05). There were 127 redistribution segments (38%) on the delayed images and 163 (49%) on the re-injection images out of 336 defects on the exercise images (p < 0.001). In normokinetic segments with significant coronary stenosis and in hypokinetic segments, redistribution was found in 42% and 45% of the defects, respectively, on the delayed images, and in 65% and 62% of the defects, respectively, on the re-injection images (p < 0.01). However, no significant differences were observed between the delayed and either the delayed or re-injection images in the akinetic segments. These results suggest that the re-injection method is useful for avoiding underestimation of myocardial viability.

Expression of E-cadherin cell adhesion molecules in human breast cancer tissues and its relationship to metastasis

E-cadherin (E-cad) is a subclass of the cadherin family that plays a major role in maintenance of intercellular junctions in epithelial tissues. In order to explore the correlation between the expression of E-cad and cancer invasion and metastasis in vivo, we performed an immunohistochemical examination for E-cad expression in 120 patients with breast cancer using our specific anti-E-cad monoclonal antibody. In noncancerous epithelial cells, E-cad was strongly expressed on cell-cell boundaries, whereas various staining patterns were observed in tumors. Of these 120 tumors, 56 (47%) showed Pr type expression of E-cad, and 64 (53%) showed Rd type or negative expression. We found significant correlations between E-cad expression and clinicopathological features. The frequency of Rd type was significantly higher in invasive ductal carcinomas (58%, 56 of 97) and poorly differentiated carcinomas (84%, 21 of 25) than in noninvasive and well-differentiated carcinomas. Furthermore, a high frequency of Rd type was detected in the following advanced tumors: T3,4 tumors, 71% (22 of 31); tumors with extensive lymph node metastasis, 74% (29 of 39); and tumors with distant metastasis, 86% (19 of 22). These values were significantly higher compared with their counterparts. The expression of epidermal growth factor receptor tended to be positive in E-cad-positive tumors. However, no significant relationship was seen among E-cad expression, menopausal status, hormone receptor status, and DNA ploidy pattern. These results suggest that the reduction of E-cad expression may play an important role in invasion and metastasis of human breast cancer.

[Vasospasm and its outcome after early surgery for ruptured cerebral aneurysms: changing pattern of its incidence and outcome during this 9-year period]

The occurrence and outcome of vasospasm (VS) were analyzed in 240 patients who had aneurysm surgery within 7 days of a hemorrhage during 9-year period (1981-89). Occurrence of VS was evaluated by the appearance of ischemic symptoms, (A) with or (B) without CT evidence of infarcts. The surgical outcome was assessed by the Glasgow Outcome Scale 6 months postoperatively. The results in the first and the latter halves of the period were compared. The overall incidence of VS (A+B) was 34.8% (A: 23.5%, B: 11.3%) and 33.6% (A: 15.2%, B: 18.4%) in the first and the latter halves, respectively. Thus, VS leading to infarction showed a tendency to decrease in the latter half of the period, though the overall incidence of VS itself was almost identical in both the first and second halves of the period. The results were also analyzed according to preoperative grading based on the Glasgow Coma Scale (GCS). The tendency toward decreased severity of VS in the latter term was most remarkable in patients with GCS total scores between 14 and 13. The decreased incidence of severe VS proved to be reflected in decreased mortality and in increased rate of good outcome in the latter half of the period. In order to confirm whether the results obtained in our clinic are universal, we applied the same analysis for control groups in four cooperative double-blind clinical trials performed during this period in Japan. The study again showed that the rate of infarction has decreased significantly over the decade, resulting in the improved surgical outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Projections of the anterior coronal gyrus to the subthalamic nucleus in the cat: a combined retrograde and anterograde WGA-HRP study

In order to re-examine the corticosubthalamic projections in the cat, WGA-HRP was injected into the subthalamic nucleus (STN). Following WGA-HRP injections into the lateral STN, a small number of retrogradely labeled neurons were found in the anterior coronal gyrus (ACG) as well as the anterior sigmoid gyrus. To confirm the projection of the ACG to the lateral STN, which had not been reported previously, WGA-HRP was injected into the ACG. Anterogradely labeled fiber terminals were found in the dorsolateral part of the STN. These results indicate that the ACG influences the STN activity through its direct projections.

Regulation of human B cell responsiveness by interferon-alpha: interferon-alpha-mediated suppression of B cell function is reversed through direct interactions between monocytes and B cells

Previous studies have revealed that interferon-alpha (IFN-alpha) suppresses the B cell responses stimulated with Staphylococcus aureus (SA) + IL-2 in the complete absence of monocytes but enhances the responses of B cells contaminated with monocytes. The current studies therefore examined in detail the combined effects of IFN-alpha and monocytes on the B cell responses induced by SA + IL-2. Monocytes overcome the suppressive effects of IFN-alpha on the IgM production induced by SA + IL-2. Thus, in the presence of monocytes, IFN-alpha enhanced the IgM production by B cells stimulated with SA + IL-2. IFN-alpha still enhanced the IgM production induced by SA + IL-2 in the presence of monocytes and indomethacin. The IFN-alpha-mediated suppression of B cell responsiveness was not overcome by addition of factors generated from SA-activated monocytes, or any of IL-1 beta, IL-6, and TNF-alpha. Of note, the IFN-alpha-mediated suppression of B cell responsiveness was overcome only when B cells and monocytes were allowed to contact with each other. This reversal of the IFN-alpha-mediated suppression of B cell function was not blocked by any of the mAb to CD11a, CD18, CD54, or monomorphic determinants of HLA-DR. These results indicate that IFN-alpha enhances the B cell responses induced by SA + IL-2 through direct interactions between monocytes and B cells that do not involve lymphocyte-function-associated-1 molecules, intercellular adhesion molecule-1, or HLA-DR antigens. Thus, the data demonstrate the presence of unique direct interactions between B cells and monocytes that regulate human B cell responsiveness.

Hepatic arterial and portal venous oxygen content and extraction in liver cirrhosis

We examined the oxygen content in the hepatic arterial, hepatic venous and portal venous blood to evaluate the oxygen supply to the liver and hepatic oxygen extraction in cirrhosis. The arterial-portal venous difference of the oxygen content was within the normal range in cirrhosis patients, although the oxygen content of the hepatic artery and portal vein was lower than in the control patients. The hepatic venous oxygen content was normal in the cirrhosis patients. The oxygen tension and saturation were always higher in the splenic vein than in the other branches of the portal system. Oxygen was supplied chiefly by the hepatic artery, and arterial oxygen extraction was normal in cirrhosis. In addition, there was no change in arterial extraction during oxygen inhalation by cirrhosis patients. Portal venous oxygen extraction was decreased in cirrhosis and was increased by oxygen inhalation. These findings indicate the autoregulation of hepatic oxygen through a mutual relationship between the hepatic arterial and the portovenous oxygen supply.

[Acute aneurysm surgery and the Glasgow Coma Scale: relationship with 6-month outcome]

A series of 610 patients who had aneurysm surgery within 7 days of the hemorrhage were analyzed as to the relationship between the preoperative Glasgow Coma Scale (GCS) score and the outcome assessed by using the Glasgow Outcome Scale (GOS) at 6 months after surgery. The patient distribution in accordance with the GCS scores in descending order from 15 to 3 was as follows: 265, 109, 44, 24, 17, 20, 25, 15, 18, 12, 16, 23, and 22 cases, respectively. In general, the larger the GCS score, the better the outcome. Thus, the overall results proved to be significantly correlated with the GCS score prior to surgery (r = 0.608, P < 0.01). As for demarcation levels along the GCS axis in terms of the GOS, a significant difference in the outcome was observed at the level of GCS scores between 15 and 14 (P < 0.0001, Wilcoxon test). However, no borderlines were evident at any GCS levels other than 15/14. The problems of applying the GCS to the grading system of aneurysmal subarachnoid hemorrhage are discussed.

[A case of adult onset hypophosphatemic vitamin D resistant osteomalacia]

A case of adult onset hypophosphatemic vitamin D resistant osteomalacia is described. A 40-year-old female who complained of thorax and lumbar pain and gait disturbance was admitted to our hospital on 7 November, 1988. The patient had hypophosphatemia with normal plasma calcium, parathyroid hormone and 25-hydroxy vitamin D3 concentrations, but had decreased tubular reabsorption of phosphate and decreased plasma 1, 25-dihydroxy vitamin D3 concentrations. The iliac crest bone biopsy showed osteomalacic changes. The 99mTc-MDP bone scintigram showed evidence of increased bone turnover with raised plasma alkaline phosphatase concentrations. After treatment with oral 1 alpha-hydroxy vitamin D3 (3-6 micrograms/day) and intravenous or oral phosphate supplement (0.47-1.74g/day), the subjective and clinical findings improved.

[Motility and mucosal hemodynamics of the lower esophagus after transabdominal esophageal transection for esophageal varices]

Lower esophageal motility and mucosal hemodynamics were investigated in 20 patients who underwent transabdominal esophageal transection for esophageal varices (ET), to evaluate their association with reflux esophagitis and variceal recurrence. In the manometric study with microtransducer catheter, maximum swallowing pressure in the lower esophagus of the patients was significantly lower than that of the healthy controls (20 cases) (26.1 +/- 20.5mmHg vs. 80.0 +/- 10.0mmHg: p < 0.01), while high pressure zone pressure did not differ between the two groups. In comparison between patients with and without esophagitis (E(+) and E(-)), maximum swallowing pressure of E(+) was statistically lower than that of E(-) (12.4 +/- 18.7mmHg vs. 31.0 +/- 19.1mmHg: p < 0.05). In the hemodynamic study by reflectance spectrophotometry, the index of esophageal mucosal blood volume (IHb) and the index of oxygen saturation of hemoglobin (ISo2) of E(+) and E(-) were no different from those in the patients with non-operated esophageal varices (10 cases). Although there was no correlation between the recurrence of RC-sign and mucosal microcirculation, the patients with larger varices tended to have a higher IHb and a patients with F1-varices had significantly lower ISo2 than the patients without varices. This study indicated that the poor clearance ability after ET may lead to reflux esophagitis and the patients with variceal recurrence had the congested mucosal microcirculation, compared to those without variceal recurrence.

[Establishment of EGF, EGF-R and FN-R positive human adenocarcinoma cell line (GAC-1)]

A human adenocarcinoma cell line designated as GAC-1, was established from ascites of the 56-year old male patient with rapidly progressive gastric cancer. The doubling time was about 18.5 hours in vitro, and cell cycle analysis using flow cytometry showed marked increase of S phase (46.1%). Immunohistochemical demonstration of GAC-1 cells revealed positive staining of TGF-alpha, EGF, EGF-R, FN-R, laminin and negative staining of fibronectin. Histogram of them indicated aneuploidy with modal number 57 and they formed tumors in nude mice.

Formation, characterization, and toxicity of the glutathione and cysteine conjugates of toxic heptapeptide microcystins

Microcystins LR, YR, and RR, cyclic heptapeptide hepatotoxins produced by cyanobacteria, were synthetically converted into glutathione (GSH) and cysteine (Cys) conjugates. Fast atom bombardment mass spectra showed [M + H]+ ions corresponding to GSH and Cys conjugates of microcystins LR, YR, and RR for the obtained compounds. 1H NMR spectral analyses revealed that two singlet signals of olefinic protons of N-methyldehydroalanine (Mdha) in microcystins disappeared in the conjugates, confirming that thiols of GSH and Cys added nucleophilically to the alpha, beta-unsaturated carbonyl of the Mdha moiety. On examination of the 50% lethal dose (LD50) with intravenous injection using mice, both GSH and Cys conjugates showed reduction in toxicity compared with microcystins, but their toxicity still remained. Microcystin LR and its GSH conjugate were separated and identified in a standard mixture by using a frit-fast atom bombardment liquid chromatography/mass spectrometry (Frit-FAB LC/MS) method. Obtained conjugates in the present study would be important compounds as the standard samples for study of metabolism of microcystins, and the Frit-FAB LC/MS method would be applicable to mass spectrometric identification of metabolites of microcystins.

Development of diabetic complications in a new diabetic strain of rat (WBN/Kob)

The development of ocular, renal, and neural lesions was examined in male diabetic WBN/Kob rats with endoexocrine pancreatic insufficiency. As for the ocular lesions, around 15 months of age, opacity of the lens began to appear. Opacity was first observed in the periphery of the lens, and then increased rapidly in severity, extending concentrically and centripetally, until total cataracts developed. The incidence of cataracts in male rats was gradually increased and reached almost 100% at 24 months of age. As for renal lesions, the 24-h urinary total protein began to increase at about 13 months of age and reached 50-300 mg/24 h at 13-28 month of age, which was significantly higher than in age-matched male Wistar rats (15-25 mg/24 h). Electrophoretic analysis revealed that the urinary protein was almost all albumin. Morphologically, an increased GBM thickness and glomeruli with segmental or global enlargement of mesangial areas were observed. As for neural lesions, a reduction in motor nerve conduction velocity was demonstrated electrophysiologically, and a marked decrease in density and diameter of myelinated fibers in the sciatic nerves were observed morphometrically. In conclusion, the WBN/Kob rat strain with slowly developing but severe lesions associated with pancreatopathy presents a suitable model for human diabetic complications.

Effect of hepatic collateral hemodynamics on gastric mucosal blood flow in patients with liver cirrhosis

The dependence of the gastric mucosal change in liver cirrhosis on the extrahepatic collaterals is still unknown. Therefore we studied the influence of these collateral hemodynamics on gastric mucosal blood flow and gastric mucosal lesions. The subjects were 23 cirrhotic patients and were divided into two groups by the findings of percutaneous transhepatic portography. The first group consisted of 14 cases whose extrahepatic collaterals were via esophageal varices (group I). The second group included 9 cases having collaterals other than esophageal varices (group II). Multiple red spots were observed in 13 of 14 cases in group I, and two of nine cases in group II. Gastric mucosal blood flow was 2.0 +/- 0.9 volts (mean +/- SD) in group I, 4.0 +/- 1.2 in group II. A statistically significant difference was observed between groups I and II. Gastric mucosal blood flow was not significantly correlated with portal venous pressure in group I. It is concluded that, in liver cirrhosis, gastric mucosal blood flow is changeable according to the types of the extrahepatic collaterals.

Structural characterization of bacitracin components by Frit-fast atom bombardment (FAB) liquid chromatography/mass spectrometry (LC/MS)

The structural characterization of minor components of bacitracin (BC) complex was carried out using a technique of liquid chromatography/mass spectrometry (LC/MS). Satisfactory total ion current chromatogram of BC complex and excellent mass spectra of many components were given by Frit-fast atom bombardment (FAB) LC/MS analytical system, and the structures of 13 minor components could be proposed. The 13 minor components were classified into two groups, bacitracin A (BC-A) related components and bacitracin F (BC-F) related components depending on their common N-terminal moieties. The structures of BC-A related components and BC-F related components were the same as those of BC-A and BC-F, respectively, except that one to three of isoleucine and leucine residues are replaced by valines. The BC-F related components were degradation products of BC-A related components through the same degradation process as that of BC-A.

Morphological features of cat thalamo-parietal projection fibers investigated by PHA-L immunohistochemistry and electron microscopy

Thalamo-parietal fibers originating from the ventroanterior-ventrolateral (VA-VL) complex in the cat were labeled with Phaseolus vulgaris leucoagglutinin (PHA-L) and examined by light and electron microscopy. PHA-L (2.5% aqueous solution) was injected iontophoretically through micropipets with anodal current pulses into the VA-VL complex. PHA-L-labeled terminals were distributed in the lateral and the suprasylvian gyri in the superficial and deep cortical layers. In layer I, horizontal varicose fibers and terminals were conspicuous in the upper one-third and were widely distributed. In the deeper cortical layers (layers III-V), varicose fibers and terminals were detected in moderate numbers. Electron microscopic examination revealed that the labeled terminals formed asymmetrical synapses on the dendritic spines of spiny neurons. These morphological findings appeared to be consistent with our previous intracellular recordings in this cortex.

[A case of dural sarcoidosis]

A 26 year-old man, who was treated for meningitis in our hospital previously, was rehospitalized 1 year later because he developed disturbance of consciousness, gait disturbance and urinary incontinence. Blood examination revealed accelerated ESR, elevated GPT, slight elevation of serum Ca, strong positive CRP, and a decrease in PHA and Con A. ACE was within normal range and tuberculin reaction was negative. Lumbar puncture revealed that the initial pressure was 310 mmH2O, cells were 152/3, and protein was 343 mg/dl. Bilateral hilar lymphadenopathy was absent in chest X ray film. Head CT revealed enlarged lateral ventricles and irregularly enhancing nodular lesions in the anterior half of the falx cerebri, and abnormally strong enhancement of the choroid plexus. Ventriculoperitoneal shunt was performed. As a diagnosis was difficult to obtain from the clinical data, biopsy of the nodular lesions was performed. The histopathologic diagnosis was sarcoidosis. Steroid hormone was administered thereafter, and the nodular lesions of the falx disappeared in the follow-up. In the literature, only 8 cases of sarcoidosis of the dura mater have been reported. Since intracranial sarcoidosis is a part of systemic sarcoidosis, its diagnosis is not difficult in most cases. However, in cases difficult to diagnose as in our case, biopsy may be necessary. When nodular lesion occurs in the dura mater, sarcoidosis must be included as a possibility in the differential diagnosis in addition to the usual meningioma, lymphoma, and metastatic brain tumor.

The medial dorsal nucleus is one of the thalamic relays of the cerebellocerebral responses to the frontal association cortex in the monkey: horseradish peroxidase and fluorescent dye double staining study

To reveal the thalamic relay nucleus of the cerebellocerebral responses in the frontal association cortex, simultaneous labeling of the cerebellothalamic (C-T) terminals and the thalamocortical (T-Cx) neurons was performed in three monkeys. Horseradish peroxidase (HRP) was injected into the deep cerebellar nuclei and small doses of HRP or fluorescent dye were injected into the prefrontal cortex. The distribution of anterogradely labeled C-T terminals and retrogradely labeled T-Cx neurons was examined in the same sections. In addition to being distributed in the ventral thalamic nuclei and nucleus X, as previously reported, anterogradely labeled terminals were distributed in the ventrolateral part of the medial dorsal (MD) nucleus where retrogradely labeled thalamo-frontal projection neurons were localized. This study revealed that the ventrolateral parts of the MD together (MDmf, MDpc and MDdc) form one of the thalamic relays of the cerebelloprefrontal responses.

[Intramedullary neurofibroma in the cervical spinal cord; a case report]

A 62-year-old woman was admitted complaining of clumsiness in both hands. On neurological examination, bilateral hand muscles were weak, both legs were spastic and hyperreflexic, all the extremities were hypoesthetic. Urological examination revealed detruser sphincter dyssynergia. Spinal CT scan demonstrated an iso density mass lesion in the cervical spinal cord, and it was markedly enhanced. On MRI, it was also markedly enhanced by Gd-DTPA. The operative finding was that an oval shaped tumor was buried in the spinal cord and was totally removed. Its histological diagnosis was neurofibroma. Intramedullary neurofibroma is rare and only 18 cases have been reported. In this case the tumor seemed to have arisen at the root entry zone and to have grown sub-pially.

Increase of migration of cultured endothelial cells by angiotensin-converting enzyme inhibitor derived from tuna muscle

The influence of angiotensin-converting enzyme (ACE) inhibitory octapeptide derived from tuna muscle (tuna AI) on the bovine aorta endothelial cell (BAEC) migration was investigated, as compared with captopril. BAEC migration was quantitated 6 d after release from contact inhibition by a teflon fence assay. The culture grown in the presence of tuna AI (1 and 10 microM) clearly exhibited an increase in migration, compared with the control. The media collected from tuna AI (1 and 10 microM)-stimulated BAECs significantly exhibited the interleukin (IL) -1 activity that was detected by the thymocyte costimulation assay with phytohemagglutinin. Although tuna AI was a weaker ACE inhibitor than captopril, the increasing effect of tuna AI on the migration and the IL-1 generation in BAECs was slightly greater than that of captopril. In quiescent BAECs, tuna AI (1 microM) apparently induced c-myc and platelet derived growth factor (PDGF) A-chain messenger ribonucleic acid (mRNA) expressions within 30 min, which persisted for 6 h. In contrast, captopril induced a very low expression of c-myc mRNA, and had no relation to PDGF A-chain mRNA expression. These results suggest that the increase of BAEC migration by tuna AI, unlike captopril, is likely related to the induction or activation of IL-1, and c-myc and PDGF mRNAs, in addition to the inhibition of the conversion of endogenous angiotensin I to angiotensin II.

Streptococcal-related antigens stimulate production of IL6 and interferon-gamma by T cells from patients with Behcet's disease

Greater attention has been recently paid to the role of certain strains of streptococcus as an etiologic agent of Behçet's disease, in which T cell abnormalities are considered to be involved. We therefore examined whether T cells from patients with Behçet's disease might to be stimulated by Streptococcus sanguis-related antigen (RRE KTH-1 antigens). T cells from 17 patients with Behcet's disease, but not those from 13 healthy individuals or from 13 patients with other rheumatic diseases, were stimulated to produce greater amounts of interleukin 6 (IL6) by addition of RRE KTH-1 antigens [stimulation index: 3.96 +/- 0.56 and 1.35 +/- 0.28 or 1.83 +/- 0.43 (mean +/- SEM), respectively]. The IL6 production by T cells required the presence of either fresh or paraformaldehyde-fixed monocytes. The enhancement of T cell IL6 production was not related to the presence of HLA-B51, which has been shown to be frequently associated with Behçet's disease. These results indicate that T cells from patients with Behçet's disease are stimulated by streptococcal antigens to produce IL6 through T cell-monocyte interactions in which binding of the antigens to monocytes, but not necessarily processing of the antigens by monocytes, is involved. Moreover, RRE KTH-1 antigens as well as Escherichia coli-derived antigens also enhanced the production of interferon-gamma by T cells from patients with Behçet's disease. The data thus suggest that T cell hypersensitivity to several bacterial antigens may play a central role in the pathogenesis of Behçet's disease.

Effects of interferon-alpha on human B cell responsiveness: biphasic effects in cultures stimulated with Staphylococcus aureus

Although interferon-alpha (IFN-alpha) has been found to be involved in the immune regulation in vivo, the effects of IFN-alpha on human B cells have not yet been clarified because of conflicting results in the literature. The present study therefore examined the effects of several subtypes of IFN-alpha (natural, alpha 1, alpha 2a, alpha 2b) on B cell responsiveness in detail by comparing different experimental conditions. Highly purified B cells from normal human individuals were cultured with Staphylococcus aureus (SA) + IL-2 or with immobilized anti-CD3-activated T4 cells in the presence or absence of IFN-alpha. IFN-alpha enhanced the immunoglobulin (Ig) production induced by immobilized anti-CD3-activated T4 cells. By contrast, IFN-alpha (5-50,000 IU/ml) suppressed the Ig production induced by SA + IL-2. The suppression by IFN-alpha was dependent on the concentration of SA. The inhibitory effects of IFN-alpha in SA-stimulated cultures were exerted in the first 72 hr of cultures and required the presence of IL-2, whereas IFN-alpha enhanced the maturation of B cells when it was added after 72 hr of cultures. The suppressive effects of IFN-alpha were overcome by addition of immobilized anti-CD3-preactivated T cells that had been treated with mitomycin C, but not by the addition of fresh T cells or soluble factors produced by activated T cells. Of interest, IFN-alpha did not inhibit the expression of IL-2R, but inhibited that of intercellular adhesion molecule-1 (ICAM-1) on B cells after stimulation with SA + IL-2, suggesting that the suppressive effects of IFN-alpha might be related to the regulation of B cell-B cell contacts through ICAM-1. There was no significant difference in effects on B cells among various subtypes of IFN-alpha. These results suggest that the effects of IFN-alpha on human B cell responsiveness may be different depending on the nature of stimulation. Moreover, the data indicate that IFN-alpha enhances the differentiation of activated B cells irrespective of the activation signals.