Influence of gingival crevicular washing on the expression of polymorphonuclear leukocyte membrane receptors before and after periodontal therapy

Extensive data demonstrate that polymorphonuclear leukocytes (PMN) are the predominant cell type involved in periodontal disease and that gingival crevicular fluid constituents are influenced by the inflamed gingiva. The aim of the present study was to evaluate the ability of gingival crevicular washing (GCW) (a dilution of gingival crevicular fluid) from periodontal sites in different clinical conditions of modulating the PMN membrane receptors involved in motility, adhesion and phagocytosis before and after periodontal treatment. 10 patients affected by adult periodontitis (AP) were selected. From each patient, 2 test sites (TS) were chosen on the basis of a probing depth > 5 mm and attachment loss, and 2 control sites (CS) with probing depth < 3 mm without. Modifications of membrane receptor density of PMN from healthy donors incubated with GCW harvested from TS and CS was evaluated using fluorescent probes and flow cytometry. Compared to CS-GCW, TS-GCW before therapy increased the expression of the beta 2 integrin CD11b and the chemotactic receptor for the oligopeptide N-formyl methionyl leucyl phenylalanine (FMLP-R) while it reduced the expression of L-selectin. GCW collected from the same TS after the successful completion of periodontal treatment did not influence PMN receptors, indicating that the clinical improvement paralleled the disappearance of the PMN modulating capability contained in TS-GCW before therapy. In conclusion, the present data illustrate the relevant modifications occurring at PMN membrane in chronic adult periodontitis exerted by GCW obtained by a simple fluid collection technique. Thus, monitoring gingival crevicular fluid PMN activating capability may help disclose the presence of chronic periodontitis and may be useful in assessing successful treatment.

Response to hepatitis B vaccine in a cohort of Gambian children

In a cohort of 1000 Gambian children immunized with four doses of 10 micrograms of plasma-derived hepatitis B virus vaccine, 44 subjects (4.4%) showed no response (< 10 mIU/ml; 6 subjects) or low specific antibody response (10 to 99 mIU/ml; 38 subjects) to hepatitis B surface antigen. Serologic indices, potentially correlated with low immunologic response, were investigated in sera obtained from these children and in sex-, age- and village-matched controls who showed a normal response. The presence of circulating immune complexes in similar proportion of responding and poorly responding children together with a low prevalence of rheumatoid factors suggested that polyclonal B cell activation was not correlated with the subnormal humoral response. Concentrations of serum immunoglobulin (Ig) and IgG subclasses did not differ in the two groups. Some of the African prevalent Ig allotypes were determined, but no significant differences in the two groups were found. The humoral response to hepatitis B surface antigen did not correlate with the response to tetanus toxoid.

Humoral response to influenza hemagglutinin: oligoclonal spectrotype and failure of thymopentin as immunoadjuvant

Influenza remains a serious cause of illness and death among certain populations. Influenza vaccines in use at present are of limited effectiveness due to the high variability of the virus, and trials all over the world are in progress to enhance their immunogenicity. Conflicting results, in fact, have been reported about the immune response to influenza vaccination in diverse populations. In this paper we analyzed the antibody response to the hemagglutinin (HA) of the H3N2 A/Shangai 16/89 strain, which was included into the trivalent 1991-92 influenza vaccine, in four groups of subjects: 8 healthy young, 13 human immunodeficiency virus (HIV)-infected and 37 elderly healthy people, 9 of whom were treated with thymopentin (TP-5). Our results show levels of anti-HA IgG before vaccination in HIV-infected and elderly people significantly lower than those of normal young subjects. After vaccination, HIV-infected and elderly healthy people showed a significant increase of specific antibodies, whereas a failure in the specific response in normal young subjects was observed, thus differences among the groups were no longer present. Moreover, the spectrotypic analysis of antibody response, by isoelectric focusing and reverse blotting, showed oligoclonal but polymorphic pattern in the majority of subjects, irrespective of the group, and more frequently lack of expansion of the spectrotype after vaccination, thus demonstrating the lack of the recruitment of antigen-specific B cells. Finally, the treatment with TP-5 did not influence the outcome of the vaccination in the group of elderly people. These results further emphasize the limited immunogenicity of influenza vaccination and the inefficacy of TP-5 as immunoadjuvant, in this model of vaccination.

[Echographic monitoring of the endometrium with a transvaginal probe in the menopause. A clinical study of 185 women in the menopause]

The aim of our study was to verify the efficacy of transvaginal ultrasound scanning as an indicator of the endometrial status in healthy menopausal women. One hundred eighty five healthy women in natural menopause were examined by vaginal sonography; the endometrial patterns were analyzed and the influence on it of body weight, menopausal age, and hormonal therapy was considered. The presence of irregular and the endometrial histology were related to the ultrasound findings. 38% of the women assumed estrogen plus progestin replacement treatment since one-two years, for menopausal complaints. 17% of all patients reported irregular bleeding during the last month. The majority of women (90%), regardless of the hormone assumption, presented en endometrial thickness less than 10 mm. 10% of untreated and treated women had an endometrial thickness between 10 and 20 mm. Among the subjects with elevated menopausal age is more frequent the imaging of endometrial layer minor than 5 mm in comparison with women in early menopause. 4% of untreated and 10% of treated women without irregular bleeding had an endometrial thickness higher than 10 mm, while 67% of women with irregular bleeding presented an endometrial layer higher than 10 mm. In treated group all women with endometrial thickness greater than 10 mm had amenorrhoea. 86% of patients had endometrial atrophy detected by biopsy; hyperplastic endometrium or endometrial cancer was not demonstrated. In conclusion, vaginal sonography is a simple and reliable method in the study of the endometrial pattern in healthy menopausal women.

The role of complement in anti-bacterial defence

The complement system consists of several proteins present in human serum interacting among themselves and with the other compounds of the immune system in the host defence process. In particular, late complement component (C5, C6, C7, and C8) deficiencies (LCCD) are closely associated with Neisseria, mainly meningitidis, infections. The aim of our study was to verify this association in an Italian population by analyzing the complement profile in survivors of meningococcal meningitis. Ten out of the 59 (17%) subjects studied had homozygous LCCD (6 C8, 3 C7 and 1 C6). The meningococcal C strain was the most widely diffused (68%) and had infected all homozygous LCCD subjects. In addition meningococcal serogroup C seemed to be the least immunogenic when compared to serogroups A and B. These data confirm the close association between homozygous LCCD and meningococcal infections from common serogroups (A, B and C) in the Italian population. Anti-meningococcal vaccination is usually recommended for LCCD subjects because it increases, both quantitatively and qualitatively, the antibody component of anti-meningococcal immune defence. We therefore analyzed the levels of anti-polysaccharide (PS) A and PSC antibodies in the members of 4 families including normal subjects and subjects with homozygous and heterozygous C7, C8 or factor H defects, before and after vaccination with only PSA+C. Surprisingly, we found the highest levels of antibodies before vaccination in homozygous subjects, followed by heterozygous and normal controls, whereas, after vaccination, homozygous subjects showed the lowest increase of specific antibodies, indicating their relative incapacity to respond to meningococcal PS alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Lack of evidence for a superantigen in lymphocytes from HIV-discordant monozygotic twins

OBJECTIVE

An HIV-associated superantigen (SAg) has been hypothesized. Here we test whether an SAg is functionally detectable in peripheral blood mononuclear cells (PBMC) from monozygotic twins discordant for HIV infection.

DESIGN AND METHODS

The V beta selective T-cell depletion found in minor lymphocyte stimulation (Mls)-positive mice is caused by an SAg encoded by the mouse mammary tumour virus. Mls is a locus whose gene product stimulates a mixed lymphocyte reaction (MLR) in mice strains identical at the major histocompatibility complex locus. If an SAg is present in PBMC and/or sorted CD4+ cells from one HIV-infected monozygotic twin, it would stimulate PBMC from the corresponding healthy monozygotic twin in an MLR. In addition, if an SAg causes V beta-selective T-cell depletion in AIDS patients, a differential proliferation to a panel of staphylococcal enterotoxins (SE) of T lymphocytes from healthy and HIV-infected monozygotic twins should become measurable.

RESULTS

No positive MLR or significant differences in the SE-driven proliferation between the healthy and the HIV-infected twins were observed.

CONCLUSIONS

Our results suggest that PBMC from the two HIV-infected twins do not express a functionally detectable SAg.

Incidence of hepatitis B virus infection among an Italian military population: evidence of low infection spread

In 1990, a prospective serological survey to estimate the rate of clinical and inapparent infection with hepatitis B virus was performed in a cohort of 1324 soldiers, 18-24 years old, during an eight-month period in Italy. At the time of enrollment the prevalence of hepatitis B markers was 4.6% (0.7% subjects positive for hepatitis B surface antigen [HBsAg], 3.0% positive for antibody to hepatitis B surface antigen [anti-HBs], and 0.9% positive for antibody to hepatitis B core antigen [anti-HBc] alone. Among the 1263 susceptible subjects who were followed-up, only 2 (0.24/100 person-years of exposure) had seroconversion for HBV markers, none of which was associated with clinical illness. Among the 9 subjects HBsAg-positive at the time of enrollment, 1 (11.2%) had lost HBsAg at the end of follow-up. These data show a low spread of HBV infection among Italian young generations.

Incidence of hepatitis A virus infection among an Italian military population

In 1990, a prospective serological survey to estimate the rate of clinical and inapparent infection with hepatitis A virus (HAV) was performed in a cohort of 1,268 soldiers, 18-24 years old, during an 8 month period in the Campania region in Italy. At the time of enrollment 318 (25%) of the 1,268 soldiers were positive for total antibodies to HAV (anti-HAV). None of them was positive for IgM anti-HAV. Among the 950 susceptible subjects who were followed up for 8 months, eight (0.8%) later seroconverted to anti-HAV positivity. This figure corresponds to an incidence of 1.3/100 person/years (eight seroconversions during 633.3 years of observation). There were two clinical (with presence of IgM-anti-HAV) and six inapparent infections. The clinical/subclinical HAV ratio was 1:3. These findings indicate that the risk of HAV infection among soldiers residing in this area is not negligible.

Evaluation of the overall degree of sensitization to airborne allergens by a single serologic test: implications for epidemiologic studies of allergy

In most epidemiologic studies of respiratory allergy, the overall degree of sensitization is usually measured by indices based on skin prick test reactions to a panel of relevant airborne allergens. In the present study we used a single assay (CAP-Phadiatop, Pharmacia, Uppsala, Sweden), which is based on the reaction between serum-specific IgE and a mixture of locally relevant inhalant allergens to measure the degree of sensitization to inhalants in the sera of 1815 young Italian men, in whom a complete diagnostic workup for respiratory allergy was performed in parallel. The intensity of reaction in the CAP-Phadiatop assay was highly correlated with: (1) an allergy index (p < 0.005), based on skin prick test reactivity to seven relevant inhalant allergens (Dermatophagoides pteronyssinus, mixed grass pollens, cat epithelium, Parietaria judaica, Olea europaea, Artemisia vulgaris, Alternaria tenuis); (2) the concentration of specific IgE to the same allergens, measured by CAP-RAST (p < 0.001), in both monosensitized and polysensitized subjects; (3) the rate of respiratory allergic diseases (p < 0.0001). Therefore CAP-Phadiatop intensity of reaction is a reliable indicator of the overall degree of sensitization to inhalant allergens. Furthermore, as demonstrated by relative operating characteristic analysis, it has an acceptable detectability power in identifying subjects with symptomatic expression of the atopy status [P(A) = 0.948]. The evaluation of the degree of sensitization to inhalants by a single and semiautomated assay represents a step forward in the standardization of procedures for epidemiologic studies of inhalant allergic diseases and for mass screening programs, which are aimed at identifying predictive markers of disease susceptibility.

Quantitative and qualitative analysis of anti-tetanus toxoid antibody response in the elderly. Humoral immune response enhancement by thymostimulin

In order to explore the humoral primary and secondary response to tetanus toxoid (TT), and to define the possible immunopotentiating effect of the thymic hormone thymostimulin, we studied 13 elderly people, selected according to the Senieur Eurage protocol, vaccinated against TT, an antigen never encountered before. Six of them were treated with thymostimulin before and during the immunization protocol. Specific anti-TT antibody level measurement and spectrotypic analysis were performed on the sera collected from the subjects at different times over the immunization protocol. In addition, spontaneous in vitro production of anti-TT antibodies as well as cutaneous delayed hypersensitivity reactions were also studied. Only one patient showed a detectable humoral immune response after the first immunization. After the booster, four of six thymostimulin-treated individuals, compared with only two of seven controls, showed in vivo anti-TT humoral response; at the same time, spontaneous anti-TT production was detected in peripheral blood mononuclear cells from five of six thymostimulin-treated individuals but only three of seven untreated controls. These differences were highly significant (p < 0.0001). In addition, only in thymostimulin-treated subjects were the levels of serum anti-TT antibodies 14, 21 and 28 days after the booster significantly (p < 0.05) higher than the baseline values. The spectrotypic analysis of anti-TT antibodies performed by isoelectric focusing and reverse blotting showed total agreement with the results from enzyme-linked immunosorbent assay.(ABSTRACT TRUNCATED AT 250 WORDS)

The changing epidemiology of hepatitis A in Italy

In 1990, the prevalence of antibodies to hepatitis A virus infection (anti-HAV) was assayed by the ELISA method on a national sample of 1000 recruits aged 18-24 years. The overall prevalence was 29.4% (22.4% in the northern and central regions, 32.2% in the south and islands; p < 0.01). Compared with a similar study conducted in 1981, the results show a marked reduction in anti-HAV prevalence (from 66.3% to 29.4%; p < 0.01). These findings reflect the improved sanitation standards in Italy and indicate that the proportion of non-immune adults is increasing, with a higher risk of symptomatic infection in the near future.

Antibody response to meningococcal polysaccharides A and C in patients with complement defects

Patients with defects of terminal complement components are particularly exposed to the risk of developing neisserial infections and seem to respond poorly to meningococcal capsular polysaccharide (PS) C via natural immunization. The sole meningococcal PSC is, on the other hand, an excellent immunogen in normal people. Considering the great importance of vaccine prophylaxis for the prevention of meningococcal infections in patients with complement defects, it is crucial to study the antibody response to the sole meningococcal PS in these patients. We therefore analysed the levels of anti-PSA and PSC antibodies in the members of four families including patients with homozygous and heterozygous defects of C7, C8 or factor H, before and after vaccination with the sole PSA + C. Surprisingly, we found the highest levels of antibodies before vaccination in homozygous subjects, followed by heterozygous and normal controls, whereas, after vaccination, homozygous subjects showed the lowest increase of specific antibodies, indicating their relative incapability to respond to sole meningococcal PS. In conclusion, this study demonstrates (1) the capacity to respond to meningococcal PS via natural immunization by patients with total complement defects, and (2) the low responsiveness to meningococcal PS via vaccine immunization by the same patients. We propose that vaccination should be given to patients lacking specific antibodies and their serological response should be assessed. In addition this study confirms previous observations on a likely lower immunogenic power of meningococcal serogroup C via natural immunization compared with the better immunogenicity of the sole PSC.

Clinical and immunological response to typhoid vaccination with parenteral or oral vaccines in two groups of 30 recruits

The clinical and immunological responses to typhoid vaccination with parenteral and oral vaccines in two groups of 30 adult male subjects were studied. Specific anti-Salmonella typhi cell-mediated immunity and total or specific anti-lipopolysaccharide faecal immunoglobulin (Ig) A titres in vaccinated subjects were monitored. Cellular antibacterial activity was significantly increased only in orally vaccinated subjects. Serum arming activity and inhibition experiments suggested an IgA-dependent cellular cytotoxicity in those orally vaccinated. In these subjects, a total and anti-lipopolysaccharide faecal IgA increase was observed lasting up to 8 months after completion of the vaccination schedule. In parenteral vaccinated subjects, an early onset transitory increase of IgM rheumatoid factor was observed. Oral vaccine was well tolerated and free of side effects, whereas 65% of parenterally vaccinated subjects reported side effects such as fever, headache, malaise and local tenderness in the injection site.

Prevalence of hyperimmunization against tetanus in Italians born after the introduction of mandatory vaccination of children with tetanus toxoid in 1968

Systematic mandatory immunization of children against tetanus was started in Italy in 1968. Prevalence of tetanus hyperimmunization (> 5 IU/ml) was assessed among 214 immune subjects born after 1968 and found to be 17.3%. This figure is significantly higher (p < 0.01) than the 10.8% found in a previous study of subjects born before 1968. This increase is statistically significant in the Center (p < 0.01) and in the South (p < 0.05) of Italy, but not in the North. Hyperimmunization is not associated with family size (odds ratio 2.16; C. I. 95% = 0.5-7.6) or the father's years of education (odds ratio 1.83; C. I. 95% = 0.6-5.3). No difference was found between urban and rural areas of residence. Indiscriminate administration of booster doses of tetanus vaccine in hyperimmune subjects in some areas could result in unnecessary vaccinations, which can cause hypersensitivity reactions.

Dramatic reduction of meningococcal meningitis among military recruits in Italy after introduction of specific vaccination

Meningococcal meningitis is still a serious infectious disease with a mortality rate that can be as high as 10% even in developed countries. Military recruits are generally a high-risk group for meningococcal disease, with a reported incidence of four to ten times greater than that of the general population. In Italy the results of the National Meningitis Surveillance Programme showed a high attack rate of the disease among recruits in 1985 as well as in 1986, with 92 and 95% of the cases, respectively, caused by serogroup C and thus preventable. These findings led to the authorities' decision to make vaccination against meningococcal disease mandatory for recruits starting from January 1987. After almost 5 years from the introduction of meningococcal vaccination, we here sum up the epidemiological and immunological effects of the vaccination. From the epidemiological point of view we have observed a dramatic reduction of the prevalence of the disease. In 1987, the year in which we had 150,000 unvaccinated and 150,000 vaccinated recruits, the protective efficacy was 91.2%. From the immunological point of view, vaccination is highly effective, as seroconversion against polysaccharide (PS) A and C is 84 and 91%, respectively. The spectrotypic analysis of the sera before and after vaccination shows that the type of response is mainly oligoclonal, like the majority of the responses to PSs, and the antibodies induced by a sole PS are not qualitatively different from the antibodies induced by natural immunization. In addition, the efficacy is not modified by environmental factors like hypoxia, as demonstrated during permanence at 16,174 feet for 20 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of stress on lymphocyte subset distribution--a flow cytometric study in young student pilots

Stressors can induce sizable modifications on immunocompetent cells. Major circulating lymphocyte subsets were quantitated in Italian Air Force student pilots undergoing intensive training and continuous evaluation, a stressful situation both physically and psychologically. Instructor pilots matched for age and assayed in parallel were used as controls. A typical flight training session was not able per se to induce immediate significant modifications of the lymphocyte subset distribution either in the students or instructors, although it did affect plasma levels of stress-related hormones such as growth hormone, prolactin and cortisol in the former. Irrespective of the time of flying, however, the percentage of CD4+ lymphocytes and the CD4/CD8 ratio were lower in students than in instructors, and the absolute number of CD8+ lymphocytes was higher in students than in instructors. In a second series of experiments, 30 student pilots were tested at the beginning and at the end of a flight course (duration 30 days). Although the percentage of CD29+ lymphocytes comprised in the CD8+ subset was reduced at the end of the course in all individuals, such a reduction was more evident in those students who failed to pass the final examination, an additional cause of psychological stress. In light of the functional significance of the lymphocyte subsets investigated, it is suggested that the present stress-induced alterations may have practical implications.

Oxygen administration increases plasma digoxin-like substance and renal sodium excretion in chronic hypoxic patients

Despite the absence of cardiac or renal pathologies, edema and mild hyponatremia may often occur in patients affected by chronic obstructive pulmonary disease (COPD). Therefore, it has been suggested that hypoxia may influence the release of different hormones regulating renal sodium handling. To evaluate the effect of hyperoxia and O2 removal on plasma digitalis-like substance (DLS) levels, 9 patients affected by COPD and 7 normal subjects were studied. After 1 h in supine position, O2 was administered for 3 h by a tight-fitting face-mask. Blood samples for plasma DLS were taken at time 0, 60, 180 min and then for 3 h after O2 removal. In normal subjects, plasma DLS did not vary after O2 administration (from basal values of 162.25 +/- 8.59 to 107.75 +/- 6.65 pg/ml at 180 min; NS), and O2 removal (143.7 +/- 16.87 pg/ml after 3 h from O2 removal; NS). On the contrary, in patients affected by COPD, plasma DLS levels increased during O2 administration (from basal values of 138.98 +/- 8.31 to 202.14 +/- 8.21 pg/ml at 180 min; p < 0.05), and returned to baseline levels (142.59 +/- 8.28 pg/ml) 3 h after O2 removal. In the same patients, DLS increase was accompanied by a rise in Na+ excretion (from 0.08 +/- 0.01 at time 0 to 0.16 +/- 0.02 mEq/min after 3 h of O2 administration; p < 0.05). In conclusion, our findings showed an oxygen-related increase in plasma DLS levels and in urinary Na+ excretion in patients affected by COPD. This phenomenon could promote Na+ urinary loss during prolonged O2 therapy in these patients and should be taken into account in their management.

Tetanus immunity among Italians born after the introduction of mandatory vaccination of children

In Italy systematic mandatory tetanus immunization of children started in 1968. In a national sample of 241 young males born after 1968 the prevalence of non-immune subjects was 11.2% (5.5% in the North-Centre, 15.9% in the South-Islands; p < 0.02). Comparing these data with the corresponding figure obtained in a previous study of subjects born before 1968 a significant decrease (11.2% versus 32.6%; p < 0.01) is observed. The prevalence of non-immune subjects born after 1968 is significantly (p < 0.01) lower than that observed in subjects born before 1968 by geographical area as well as by area (urban/rural) of residence. These findings indicate that the introduction of compulsory tetanus vaccination for all newborns has favourably affected the immune status of younger Italian men. However, more efforts should still be addressed to decrease regional inequalities in the delivery of health care.

Effects of high altitude exposure on plasma and urinary digoxin-like immunoreactive substance

Six young healthy subjects underwent a 20 day exposure to altitude, at 4930 m (16,174 ft), to evaluate possible plasma and urine digoxin-like immunoreactive substance (DLIS) changes accompanying the altered water and electrolyte balance induced by hypoxia. We studied DLIS, plasma renin activity (PRA), aldosterone, atrial natriuretic peptide (ANP), and arginine vasopressin (ADH) in serial blood and urine samples. An increase in DLIS in plasma (P less than .005) and urine (P less than .01) was found, while aldosterone was decreased (P less than .02). PRA, ADH, and ANP did not change significantly. A trend to a greater loss of sodium through urinary excretion, correlated with urinary DLIS values (r = 0.47, P less than .01), was observed. Data suggest a possible important role of DLIS in adaptive response of human organism to high altitude.

Presentation of superantigen by human T cell clones: A model of T-T cell interaction

Superantigens (SAg) interact with T lymphocytes bearing particular V beta sequences as part of their T cell receptor (TcR). The interaction, however, requires the presence of major histocompatibility complex (MHC) class II molecules on antigen-presenting cell (APC). In peculiar circumstances, MHC class II+ T cell clones (TCC) have been shown to present peptides and selected antigens interacting with antigen-specific TCC in the absence of APC. In this report we studied the capacity of SAg to mediate a T-T cell interaction, investigating the TCC ability to present a panel of staphylococcal enteroxins (SE) independently of the presence of added APC. Upon exposure to a broad range of SE concentrations, MHC class II+ TCC showed an intense proliferative response even in the absence of professional APC. Diverse SE optimally stimulated responder TCC at different concentrations. The proliferation was inhibited by anti-DR monoclonal antibodies, both in the presence and in the absence of APC. The SE activation of TCC in the absence of APC induced the same series of phenotypic variations as that observed following the TCC stimulation with APC. Irradiated TCC efficiently presented membrane-bound SE to responder TCC as well as professional APC. These results show that a single cell of a given clone effectively presents the SE to other cells of the same clone, and provide evidence that SAg can efficiently mediate T-T cell interaction. In addition, the possibility also exists that one cell of the clone can actually undergo an auto-stimulation via SAg-mediated interactions between its own TcR and MHC class II molecule. It has recently been suggested that the V beta-selective depletion of T cells observed in acquired immunodeficiency syndrome (AIDS) patients might be a consequence of the interaction between a human immunodeficiency virus (HIV)-encoded SAg and T cells expressing a SAg complementary V beta. We suggest that the hypothesized HIV-encoded SAg might mediate T-T cell interactions that could play a relevant role in the V beta-selective depletion of T lymphocytes observed in HIV-infected patients.

Multiparametric flow cytometric analysis of the kinetics of surface molecule expression after polyclonal activation of human peripheral blood T lymphocytes

In this report we have analysed the kinetics of modulation of human peripheral blood T lymphocyte membrane molecules upon activation with optimal amounts of phytohaemagglutinin (PHA) and concanavalin A (ConA). The following activation-related and differentiation/adhesion molecules were selectively and concomitantly investigated on CD4+ and CD8+ subsets by dual colour flow cytometry: CD69, CD25 and CD71; CD2, CD45RA and L-selectin. Cultures were assayed after 24, 48, 72, 120 and 168 h of incubation with PHA and ConA. This approach allowed a comprehensive evaluation of membrane phenomena occurring during activation of normal resting human T lymphocytes. Data show that the kinetics of expression of these molecules follows a precise and consistent time-course with no major differences between CD4 and CD8 subsets. CD69 expression peaked at 24 h, whereas CD25 and CD71 expression peaked at 48/72 h with some differences between PHA and ConA activation. L-selectin expression started an evident decrease in step with culture time whose magnitude was dependent on the lectin used, being higher with PHA than with ConA. Conversely, the expression of CD45RA remained stable for 72 h and then briskly decreased with no major differences between PHA and ConA activation. CD2 molecules increased with time in number and density, although the percentage of positive cells remained essentially constant (greater than 85%). After 48/72 h of stimulation about 10% of cells co-expressed CD4 and CD8 molecules. To ascertain whether the phenomenon was restricted to cells in a particular activation state, the phenotype of cells in the diverse phases of the cell cycle was established. Results obtained show that only actively proliferating cells, that is cells in S and G2-M phases, co-expressed the two molecules, suggesting that such a phenomenon reflects a momentary dysregulation of the normal sequence of gene expression. The present data are also discussed in the light of the dynamic role of T lymphocyte activation and adhesion molecules in regulating cell-cell interactions, tissue localization and eventual immunological function.

Complement deficiency and antibody profile in survivors of meningococcal meningitis due to common serogroups in Italy

A collaborative survey was carried out in Italy on a group of 59 subjects with a past history of meningococcal meningitis. The aim was to evaluate the prevalence of complement deficiencies, the serogroup of meningococci responsible for the disease and other possible immune abnormalities associated with the infection. Complement analysis allowed the detection of 10 cases (17%) with deficiencies of the terminal components, and in particular six cases of C8 beta, three of C7 and one of C6 defect. Half of the subjects with complement deficiencies had recurrences of meningitis and developed the infection at an older age in comparison with the control group with normal complement activity. The meningococcal C strain was the most diffuse (68%) and infected all the complement-deficient subjects. Evaluation of the antibody response to meningococcal capsular polysaccharides (PS) showed that only 42.5% of the individuals with group C had antibodies as opposed to 83% and 100% of the patients with meningitis due to group A and B, respectively. In all 59 subjects serum Ig as well as IgG subclasses were present, at normal levels for the age. Vaccination of seven out of the 24 subjects without detectable anti-meningococcal PS antibodies with the sole PS A+C induced a normal response in six of them, including a subject with complement defect. In the subject who did not respond to the antigen, the antibodies against the ubiquitous pneumococcal PS type 14 were also lacking, whereas anti-tetanus toxoid (TT) antibodies were normally present. From these data we may conclude the following: (1) the high prevalence (17%) of late complement components defect among survivors of meningococcal meningitis is also confirmed in the Italian population; (2) the serogroup C, responsible for the infections in all the cases with late complement components defect, is highly recirculating in Italy and apparently less immunogenic; (3) specific vaccination with meningococcal PS is a valid prophylaxis in subjects with lack of specific antibodies as well as in subjects with complement defect.

Changing epidemiology of hepatitis B in Italy: public health implications

In Italy, a dramatic decline of hepatitis B infection occurred in recent years as a result of nonmedical and medical factors. The national type-specific surveillance system shows that the age of maximum incidence changed from early childhood, when the risk of becoming a chronic carrier after infection is very high, to late adolescence. Data of several seroepidemiologic studies are consistent with this picture, but could not be compared with previous data on similar age groups. In 1981, a seroepidemiologic study on a national sample of 5,005 recruits showed a high prevalence of serologic markers of hepatitis B infection among young adults in Italy. In 1990, the authors replicated that original study on a national sample of 4,993 recruits. The adjusted prevalence of hepatitis B core antibodies among Italian male recruits dropped from 16.8% to 5.8% in 9 years. The authors anticipate a substantial reduction in the rate of production of chronic carriers and the rates of liver cirrhosis and primary liver carcinoma in Italy in the next decades. Vaccination campaigns, especially if combined with nonimmunologic preventive measures, will further reduce the rate of hepatitis B infection in Italy.

The effects of hypobaric hypoxia on specific B cell responses following immunization in mice and humans

In order to get some insight on the physiology of the immune system during prolonged exposure to hypobaric hypoxia we evaluated the effects of high altitude on the in vivo immune response to a T-independent antigen. A group of 18 men who participated in a scientific project EV-K2-CNR to Mount Poumori, Nepal for 20 d at 4,930 m (16,174 ft) were immunized with a single subcutaneous dose of antimeningococcal vaccine Menpovax A + C (Sclavo) containing 50 micrograms of polysaccharide A (PsA) and 50 micrograms of polysaccharide C (PsC) of N. meningitidis. A group of 18 men of comparable age were vaccinated at sea level. Antibody titers against both polysaccharides were determined by enzyme-linked immunosorbent assay (ELISA) before and 18 d after vaccination. All subjects examined developed a good antibody response and no statistically significant differences were observed between the two groups. Spectrotypic analysis of antibody response to PsC was also performed by isoelectric focusing. No qualitative differences in the antibody response to PsC were found in the hypoxia-exposed group with respect to the control group. A group of 10 BALB/c inbred mice were kept in a hypobaric chamber at 5,500 m (18,000 ft) for 30 d. After 10 d, the mice were vaccinated with 1 micrograms of Menpovax A + C. Anti-PsA and anti-PsC antibodies were quantified by ELISA in sera collected at day 0 and 30. A control group of 10 mice of the same strain underwent the same study protocol but at sea level. Both groups developed a good antibody response to both polysaccharides and no significant differences were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Lack of specificity in the mechanisms involved in the enhancement of the concanavalin A driven human T lymphocyte stimulation by beta-endorphin: studies on activation marker expression, cell cycle and interleukin release

We report on the effects of a physiological concentration of Beta-Endorphin (BE) (10(-12)M) on Concanavalin A (ConA) stimulated human peripheral blood T-lymphocytes and monocytes. We evaluated the effect of timing of BE addition to the culture medium on thymidine uptake, the kinetics of expression of activation markers (CD69, CD25 and CD71) on CD4+ and CD8+ lymphocytes, and of class II MHC antigens on CD14+ cells (monocytes), the kinetics of interleukin-1 (IL-1), interleukin-2 (IL-2) and interferon gamma (IFN-gamma) release, and the cell cycle. Data show that BE is able to influence T lymphocyte only when added together with ConA at the beginning of culture, suggesting its major activity is on the early phases of the T cell response. BE did not increase the amount of class II MHC antigens on monocytes and did not preferentially stimulate CD69, CD25 and CD71 antigen expression on either CD4+ or CD8+ lymphocytes. After 24 hours, the relative proportions of CD4+ and CD8+ lymphocyte in S and G2-M phases were not affected by BE, although the opioid did augment the number of cells in the proliferative compartments of the cell cycle, S and G2-M, indicating an actual increase in the number of cells committed to proliferation. BE did not consistently influence the amount of IL-1, IL-2 and IFN-gamma found in the supernatant of ConA stimulated cultures. The mechanism of the enhancing effect on the proliferative response of normal human lymphocytes to ConA by BE, does not seem to be selective for or unique to specific lymphocyte subsets.

Clonotypic analysis of human antibodies specific for Neisseria meningitidis polysaccharides A and C in adults

Serum antibodies to the capsular polysaccharides A and C (PSA and PSC) of N. meningitidis in healthy adults before and after vaccination with the sole polysaccharides were analysed by isoelectric focusing (IEF). Before vaccination, 49% and 28% had naturally acquired antibodies against PSA and PSC, respectively, whereas 18 days after vaccine administration 84% and 91%, respectively, showed a detectable spectrotypic pattern. Oligoclonality appeared to be the main feature of naturally acquired and vaccine-induced antibodies for both polysaccharides. In all subjects the anti-PSA response, showing dominant bands at the same pH position, was more homogeneous than anti-PSC one. Most subjects with naturally acquired antibodies (25 out of 38 for PSA and 20 out of 22 for PSC) showed a spectrotypic pattern after vaccination, similar to that observed before vaccination (any differences were just related to band intensity), suggesting that PSA and PSC are able to recruit the same B cell clones previously primed with a T-dependent form of the antigen, i.e. the whole bacterium. However, in one-third of subjects with naturally acquired anti-PSA antibodies, the appearance of new alkaline bands after vaccination was observed. Furthermore, in subjects with absence of detectable natural antibodies, the vaccine-induced antibody response started in correspondence of alkaline pH areas, subsequently extending to neutral and acidic areas. Therefore, it may be hypothesized that alkaline antibody-secreting B cell clones are the first to be recruited. The final spectrotype in these subjects was similar to that observed in subjects with naturally acquired antibodies. This observation, together with the above reported data, allow us to conclude that natural (T-dependent pathway) and vaccine (T-independent pathway) immunization induce the expression of the same antibody repertoire, for both meningococcal PSA and PSC.

Fetal echocardiography using transvaginal and transabdominal probes during the first period of pregnancy: a comparative study

The authors compare the diagnostic possibilities of fetal transabdominal echocardiography versus transvaginal echocardiography. A larger diagnostic capacity is verified in different gestation ages with transvaginal probe between the 11th and 14th week of gestation. The results are emphasized by colour Doppler.

Peripheral T-cell subset imbalance in patients with vitiligo and in their apparently healthy first-degree relatives

Twenty-two patients with vitiligo had lesions stable for at least 1 year and 23 apparently healthy first-degree relatives were studied for T-cell subpopulations using monoclonal antibody technique. High levels of CD4+ lymphocytes and high CD4/CD8 ratios were found in both patients and their relatives, as compared with normal age-matched and sex-matched controls. This immunologic abnormality, together with the presence of autoantibodies previously reported in the apparently normal relatives, seems to be the hallmark of the disease. Further support of this interpretation comes from the observation that two out of the 23 apparently healthy relatives went on to develop vitiligo in a 2-year follow-up.

Antibacterial polysaccharide antibody deficiency after allogeneic bone marrow transplantation

Allogeneic bone marrow-engrafted adults immunized with meningococcal types A and C and pneumococcal type 14 polysaccharide antigens showed only low antibody titers of the IgM class, no antibody titers of the IgG or IgA classes, and no bactericidal activity in vitro. The analytical isoelectrofocusing showed the appearance of a restricted pattern of clonotypes in a minority of subjects. These observations are consistent with the hypothesis that B cells in bone marrow transplant patients express some characteristics of neonatal B cells and suggest that polysaccharide-protein conjugates, rather than isolated polysaccharide, might be utilized in the setting of bone marrow transplantation.

The use of Phadiatop in mass-screening programmes of inhalant allergies: advantages and limitations

The validity of Phadiatop as a tool in the mass screening for inhalant allergies was investigated. Seventy-nine out of 600 recruits (13.2%) were classified as allergic to inhalant allergens (68 oculorhinitis; 11 asthma) on the basis of positive history, confirmed by skin testing and/or RAST for the seven most common aero-allergens in Italy. Another 74 subjects had positive RAST and/or skin tests, yet had never experienced allergic symptoms. Phadiatop was positive in 145/600: in 78 out of 79 allergics and in 67 RAST-positive non-allergics. Correlation between Phadiatop and RAST was statistically significant, though higher for grass pollens (r = 0.85, P less than 0.001) than for Dermatophagoides pteronyssinus (r = 0.68, P less than 0.01). PRIST (cut-off 220 IU/ml) identified 36/79 allergics (45.6% sensitivity, whereas that of Phadiatop was 98.7%). As the high percentage of cases in the unselected population had specific serum IgE against inhalant allergens and no allergic symptomatology, the Phadiatop-positive predictive value falls to 53.7%, thus creating the need for Phadiatop-positive subjects to undergo further investigation for an appropriate diagnosis. Given this limitation, Phadiatop appears to be an important step forward in the field of mass-screening programmes for inhalant allergies.

Flow cytometric evaluation of nitro blue tetrazolium (NBT) reduction in human polymorphonuclear leukocytes

Oxidative metabolic burst of activated human polymorphonuclear leukocytes (PMN) is most commonly investigated in clinical practice by evaluating nitroblue tetrazolium (NBT) reduction at the single cell level. Reduced NBT precipitates where the redox reaction has taken place and can be visualized as PMN-associated dark blue granules of formazan in light microscopy. Although widely used and not technically demanding, this method remains subjective and labor intensive, especially when large numbers of samples need to be investigated. We developed a new flow cytometry technique in which PMN membrane was rendered fluorescent by a short incubation with fluorescein-conjugated Concanavalin A. PMN were then incubated with NBT and increasing doses of a suitable stimulus, such as phorbol myristate acetate (PMA). Formazan has a distinct peak of absorption at 520 nm that represents the peak of emission of fluorescein. As a consequence, formazan quenches the PMN-associated fluorescence. Data show that a dose-dependent reduction of fluorescence can be obtained using graded amounts of PMA in normal PMN cultures. PMN-associated fluorescence remains unchanged in control patients with chronic granulomatous (CGD) disease, a disorder characterized by a selective impairment of PMN oxidative metabolism. Electronic cell size increases upon PMA incubation in normal PMN, irrespective of the presence of NBT. Conversely, forward light scatter intensity decreases in the presence, but not in the absence, of NBT indicating that the phenomenon is due to the capacity of formazan to absorb/scatter the incident light. The present method for easily detecting NBT reducing activity at single cell level by flow cytometry makes use of commonly available, inexpensive reagents and standard instrumentation. It could become a useful test for clinical purposes.

Prevalence of HBV markers in the Italian Armed Forces and HBV vaccination

Hepatitis B (HBV) markers were studied in 710 subjects who had been on active duty for over 6 months in the Italian Armed Forces. The prevalence of HBsAg carriers was found to be 4.4%, while 31.6% of the subjects were positive for various HBV antibodies. A total of 137 subjects were vaccinated with an anti-HBV vaccine (HB-VAX, MSD). The percentages of non-responders and low responders were 13.86% and 13.14%, respectively. Boosters administered 3 months post-vaccination schedule, with or without immunostimulatory treatment, resulted in seroconversions and/or substantial increases in HBsAb levels in 50% of these subjects.

A new test for specific IgE to inhalant allergens (Phadiatop) in the screening of immediate respiratory hypersensitivity states

Three hundred recruits were classified as either allergic or nonallergic to inhalant allergens on the basis of history, physical examination, skin testing, and RAST. Forty-nine (16.3%) were classified as allergic as they were affected by oculorhinitis and/or asthma. This diagnosis was compared with results obtained with PRIST and with a new commercially available multi-RAST test for inhalant allergy, Phadiatop (Pharmacia). Sixty subjects (20%), including all 49 allergic subjects, scored positive in the Phadiatop assay (100% sensitivity) while PRIST (cut-off 220 IU/mL) identified only 20/49 allergics (40.8% sensitivity). The correlation between RAST and Phadiatop was excellent. Phadiatop is much more sensitive than PRIST; furthermore, Phadiatop is easier, less expensive, and as reliable as RAST for use in mass screening programs.

Complement activation is associated with the presence of specific human immunodeficiency virus (HIV)-anti-HIV immune complexes in patients with acquired immunodeficiency syndrome-related complex or lymphoadenopathy syndrome

The complement system was examined in a group of eight patients (six with lymphoadenopathy syndrome (LAS); two with acquired immunodeficiency syndrome (AIDS)-related complex (ARC], who were found to be human immunodeficiency virus (HIV)-positive, for the presence of specific HIV-anti-HIV complexes. A significant impairment of the classical and/or alternative pathway was found associated with the presence of cleavage fragments of C3 and/or B and a significant reduction in the complement factors studied. Ultracentrifugation fractions of serum samples obtained from one of the patients were assessed for the detection of specific HIV-anti-HIV (GP41-anti-GP41) complexes and were incubated with normal human serum to determine their complement activation capacity. A clear complement activation was found with the fraction in which a clear peak of HIV-anti-HIV (GP41-anti-GP41) immune complexes was present. The results demonstrate that specific immune complexes and complement activation are sometimes concomitantly present in patients with AIDS-related disease and that specific immune complexes may be one of the causal factors of the pathogenesis of complement activation in these patients. Possible consequences for the severe immune regulation with relevance to the dramatic failure in treating the virus effectively are discussed.

A comparative in vitro study of low pH and enzyme treated immunoglobulin preparation for intravenous use

Three not yet commercially available immunoglobulin preparations, intended for intravenous administration, were tested for their purity, physical integrity and in vitro functional activity. Preparations had been factory treated either at pH 4 and with insolubilized pepsin or at pH 4.25 only. Nephelometry revealed a high degree of isotypic purity (IgG greater than 99%). Gel filtration and SDS-PAGE analysis showed only trace amounts of aggregates and/or contaminants, particularly in one of the pepsin treated preparations. Protein A binding inhibition test and phagocytosis of Candida albicans by normal human polymorphonuclear leukocytes, after opsonization of the yeast with different concentrations of immunoglobulin preparations, showed the functional integrity of both the Fc and F(ab)2 regions in the three IgG preparations. Compared to previously reported methods of preparation which produce structural alterations of the Ig molecule, present data indicate the suitability of preparative methods aimed at preserving the integrity of the Ig molecule. Preparation and storage at pH 4.25 without any other treatment appear to be sufficient to obtain pure, aggregate free and in vitro functionally active Ig preparations.

Intravenous immunoglobulin preparations: a comparative in vitro study of Fc mediated functions

An ideal immunoglobulin (Ig) preparation intended for clinical use should be safe and efficacious. Efficacy depends on suitable levels of protective antibodies against pathogens and the functional integrity of the Ig molecule. In the present paper, the functional integrity of the Ig molecule was investigated in eight intravenous Ig preparations commercially available in our country and compared to an intramuscular preparation. The experimental approach included protein A and rheumatoid factor binding, complement activation and opsonic activity. Ultracentrifugation profiles were obtained for all Ig preparations in order to ascertain the presence of components other than the expected 7S monomeric IgG. Immune complexes were investigated with C1q solid phase and conglutinin assays. Results show that chemical treatments such as sulfonation or reduction-alkylation, and enzymatic treatment such as plasmin digestion, variably but consistently impair Fc-mediated functions. The present data emphasize the use of in vitro tests for assessing the suitability of Ig preparations for intravenous administration.

New, simple flow cytometry technique to discriminate between internalized and membrane-bound particles in phagocytosis

This report describes a new flow cytometry technique to measure phagocytic activity and discriminate simultaneously between internalized and membrane-bound particles. Fluorescein-conjugated heat-killed Candida albicans (F-Ca) are opsonized with purified antibodies or normal human serum and used as targets for human polymorphonuclear granulocytes (PMN). The procedure is based on the observation that F-Ca lose their green fluorescence and acquire red fluorescence upon incubation with ethidium bromide (EB) through the resonance energy-transfer phenomenon occurring between the two fluorochromes. PMN are incubated with opsonized F-Ca particles for 20 min at 37 degrees C or, as a control, at 4 degrees C and in the presence of cytochalasin B, an inhibitor of the phagocytic process that does not affect membrane binding of F-Ca. EB is added, and green and red fluorescence associated with PMN is evaluated using a mercury-lamp-powered instrument. Because EB does not penetrate intact cell membranes, internalized particles are not affected by EB and remain green, whereas membrane-bound particles assume an intense red stain. By means of contour plot analysis, the number of PMN containing and/or binding F-Ca particles can be readily assessed. The method described here allows precise quantitative analysis of the phagocytic process on the part of human PMN in a single, one-step assay that does not require sophisticated instrumentation or reagents and should prove to become a test suitable for clinical purposes.

Hydatid disease: analysis of parasite antigens in circulating immune complexes and in preformed hydatid antigen-antibody complexes

Fifty-three sera from 29 patients with hydatid disease, all but one positive for specific anti-parasite antibodies and all negative for specific circulating antigens, were studied for the presence of circulating immune complexes (CIC) by conglutinin binding-assay (KgBA). Fourteen serum samples (26%) from eight patients (27%) were positive. These positive sera were pooled for each patient and the eight samples were PEG-precipitated and analysed for the presence of specific Echinococcus granulosus antigens in the CIC using a human anti-human-hydatid cyst fluid antiserum capable of recognizing the major antigenic systems of the parasite namely, antigens 4 and 5. The assays utilized for detecting antigen in CIC were: (a) blotting on nitrocellulose paper after sodium dodecil sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and specific immunological detection; (b) ultracentrifugation in acid buffer and subsequent detection of antigens by a sandwich-radioimmuno assay (RIA); (c) protein separation by isoelectric focusing (IEF) and specific immunological recognition. In addition, all positive sera were analysed for the presence of antigen in the CIC by a modified KgBA and by polyethylenglicol (PEG)-precipitation in acid buffer followed by immunological recognition of antigen. All tests gave negative results with the patients' samples, but were positive with preformed in vitro complexes between parasite antigens and corresponding antibodies. Failure to detect antigen in the CIC could be due to: 1) insufficient sensitivity of the assays used to detect hydatid antigens in CIC; 2) rapid clearance of antigen or CIC from the circulation; 3) presence of parasite antigen not recognized by the antiserum employed; 4) production of CIC as a result of polyclonal B-cell activation. This last hypothesis is supported by the demonstration of IgM-rheumatoid factor (RF) and anti-F(ab')2 antibodies respectively in 11 (44%) and 13 (52%) out of 25 patients.

Spectrotypic analysis of humoral response in human hydatidosis

The spectrotypic patterns of anti-Echinococcus granulosus and anti-F(ab')2 antibodies were analysed in 13 patients with different forms of hydatidosis by means of isoelectric focusing (IEF). Specific anti-echinococcus antibodies and specific echinococcus antigens were obtained by crossed affinity chromatography between patient serum and cyst fluid, as previously described (D'Amelio et al., 1985). A wide spectrotype in the pattern of anti-Echinococcus antibodies was observed, with strong homologies among the different sera mainly at acid and neutral pH. One serum displayed faint, nearly inapparent bands. Conversely, the pattern of anti-F(ab')2 antibodies in the six patients in whom they were positive was limited but heterogeneous, ranging from monoclonal through oligoclonal to polyclonal. A predominant clone was identified in the patient with a polyclonal pattern. A correlation between qualitative IEF spectrotypic patterns and the quantitative results of immunoenzymatic assays was observed for both types of antibodies.

Comparative analysis of immunological responses to oral (Ty21a) and parenteral (TAB) typhoid vaccines

The clinical and immunological responses to typhoid vaccination with parenteral (TAB) and oral (Ty21a) vaccines in two groups of 30 adult male subjects were studied. Parameters monitored included specific anti-Salmonella typhi cell-mediated immunity and total and specific antilipopolysaccharide fecal immunoglobulin A (IgA) titers in Ty21a-vaccinated subjects. Peripheral blood lymphocytes antibacterial activity was significantly increased only in Ty21a-vaccinated subjects. Serum arming activity and results of human F(ab')2 anti-IgG and -IgA inhibition tests suggest antibody-dependent cellular cytotoxicity mediated by IgA in those vaccinated with Ty21a. Interestingly enough, the cells of TAB-vaccinated subjects were able to mediate IgG-dependent cellular cytotoxicity, as was observable from the results of blocking experiments. Moreover, total and specific antilipopolysaccharide fecal IgA levels were observed to be significantly increased with Ty21a, up to 8 months post-vaccination schedule. An early-onset, transitory increase in serum IgM rheumatoid factor was also found, exclusively in subjects treated with TAB, and was no longer detectable on day 240. Ty21a was well tolerated and free of side effects, whereas 65% of subjects administered TAB reported fever, headache, malaise, and local tenderness at the injection site. Our data show that the two typhoid vaccines induce different cell-mediated specific immune responses. The role of these responses in protection against Salmonella infection, however, requires further investigation.

Rapidly progressive periodontitis. Neutrophil chemotaxis inhibitory factors associated with the presence of Bacteroides gingivalis in crevicular fluid

In the last few years several bacteriological and immunological studies have investigated the role of bacteria and immune defects in order to establish the etiopathogenesis of periodontal disease. With regard to the immune system, a defect in polymorphonuclear neutrophil (PMN) chemotaxis has been frequently reported in patients with rapidly progressive or juvenile periodontitis. The purpose of this study was to investigate in five patients with rapidly progressive periodontitis and normal chemotaxis of peripheral blood PMNs the presence of chemotaxis inhibitory activity in gingival fluid and to relate such activity to three types of bacteria, often involved in rapidly evolving periodontal lesions, that are able to inhibit in vitro PMN chemotaxis: Bacteroides gingivalis, Capnocytophaga sp., and Actinobacillus actinomycetemcomitans. We found strong inhibitory activity in three of these patients. This activity was consistently associated with the finding of B. gingivalis in gingival pockets. We cannot rule out, however, that other substances not of bacterial origin could be responsible for such inhibitory activity. The strict association with B. gingivalis, known to secrete blocking factors, is highly suggestive, although this data must be considered preliminary.

Evaluation of the presence of RF-like activities in immunoglobulin preparations for intravenous use. I. IgG anti-IgE in intravenous Ig

We have studied the IgG anti-IgE antibody content of 8 IgG preparations for intravenous administration that we use in our Day Hospital as replacement therapy for patients with hypogammaglobulinemia. In all preparations we found the presence of both IgE and IgG anti-IgE as monomers and oligomers after fractionation with ultracentrifugation on sucrose gradient. This RF-like activity seem to be an essential constituent of low m.w. aggregates, disappearing at acid pH. We suggest that its presence could be responsible for the enrichment of IgE in Ig preparations for therapeutic use and perhaps for immediate and long-term adverse reactions.

Characterization of specific immune complexes in HIV-related disorders

Eighty-seven seropositive subjects with HIV (human immunodeficiency virus) infection together with 20 normal controls with no history of any illness were investigated for the presence of circulating immune complexes (CIC) by the conglutinin binding assay (KgBA) and further studied for isotype characterization of CIC. Six out of 87 patients showing very high values for immune complexes (CIC) were studied for the presence of free antigen. In 3 out of 6 (1, IVc1; 1, III; 1, IVa) we could detect by ultracentrifugation analysis the presence of specific HIV (p15) anti-HIV (anti-p15) and gp41-anti-gp41 CIC. Evidence in favour of this finding is supported by: the presence of specific CIC (p15-anti-p15 or gp41-anti-gp41) seen only at pH 7.2; the apparent presence of free antigen and specific HIV antibodies were only at pH 4.0. The relevance of this finding lies in the attempt to explain the occurrence of false seronegativity seen occasionally in symptomatic patients. Thus, the presence of CIC might perhaps interfere in the routine assay (i.e. ELISA) making the diagnosis difficult. All these considerations will have to be taken into account in the future handling of this disease.