Immunological and Viral Markers of Hiv Infection and Retinal Microangiopathy

The relationship between retinal microangiopathy and some features of human immunodeficiency virus (HIV) infection such as HIV antigenemia, antibodies to the viral proteins, T lymphocyte subsets, were studied in 71 patients with acquired immunodeficiency syndrome (AIDS). The absence of antibodies to the HIV p24 protein was significantly related to retinal microangiopathy (p = 0.0051) and more closely to retinal cotton-wool spots (p = 0.0007); the combination of positive antigenemia with the absence of antibodies to p24, which is typical of the later phases of HIV infection, was found in a larger percentage of patients with cotton-wool spots (p = 0.0013) than in subjects with every sign of microangiopathy (p = 0.0546). T-helper (CD4+) cells count below 200 cells/mm3 was also detected in a higher percentage of patients with HIV-related retinal microangiopathy (p = 0.009). These findings suggest that retinal microangiopathy and especially retinal cotton-wool spots are related to the progression of immunodeficiency.

A controlled trial of nevirapine plus zidovudine versus zidovudine alone in p24 antigenaemic HIV-infected patients. The Dutch-Italian-Australian Nevirapine Study Group

OBJECTIVES

Nevirapine is a non-nucleoside reverse transcriptase inhibitor of HIV-1 which exhibits synergy in vitro with zidovudine (ZDV) and also is active against ZDV-resistant HIV. We evaluated the activity and safety of nevirapine in combination with ZDV in patients receiving long-term ZDV therapy.

METHODS

We conducted a randomized, open-label, controlled 28-week study of nevirapine (200 mg daily for 2 weeks followed by 200 mg twice daily for 26 weeks) and continued ZDV (500-600 mg daily) versus continued ZDV alone in 49 HIV-1 p24 antigenaemic patients with CD4+ lymphocyte counts < 500 x 10(6)/l and who had been treated with ZDV for at least 6 months.

RESULTS

Addition of nevirapine to ZDV resulted in a significant and rapid reduction in circulating RNA load (mean, 0.65), a mean CD4+ lymphocyte rise of 34 x 10(6)/l, a reduction in serum beta 2-microglobulin and a median fall in immune complex dissociated p24 antigen levels of 69%. These changes remained statistically significant for 4, 4, 12 and at least 28 weeks, respectively. The principal adverse event due to nevirapine was a hypersensitivity reaction comprising rash with or without fever and mucositis in eight (32%) patients, which was dose-limiting in seven patients.

CONCLUSION

Nevirapine exhibits significant although transient anti-HIV activity in ZDV-pretreated patients but its use is frequently associated with a hypersensitivity reaction.

[Pancreatitis during treatment of leishmaniasis with n-methylglucamine antimoniate in a subject infected with HIV]

In this study the authors report the case of HIV patients with visceral leishmaniasis. He presented a pancreatitis with evident clinical signs and high increase of amilasis (9876 U/L) the twelfth day of treatment with meglumine antimoniate. The interruption of therapy was followed by a rapid disappearance of signs and symptoms and a normalization of amilasis. In accordance with the most recent studies, it is expedient, for every patients treated with antimonial drugs, to undergo an accurate amilasis monitoring.

Cerebrospinal fluid antiganglioside antibodies in patients with AIDS

In this study the presence of brain antiganglioside antibodies in the cerebrospinal fluid (CSF) of patients with HIV infection was analysed. CSF samples were collected from 45 patients with AIDS and from 45 anti-HIV negative subjects, 15 of whom presented aseptic meningitis. Nineteen AIDS patients had clinically well-documented encephalopathy. Thirteen of these patients had white matter lesions shown by magnetic resonance imaging (MRI). Both IgG and IgM antiganglioside antibodies were detected by immunostaining on thin layer chromatography plates in three CSF samples from AIDS patients with progressive encephalopathy with signs of a diffuse demyelination, as revealed by MRI. Two of these CSF samples reacted specifically with GM3, GM1 and GD1a and one with GD1a. In none of the HIV infected patients without demyelinating encephalopathy, but with opportunistic infections or cerebral lymphoma, nor in the anti-HIV negative control subjects were antiganglioside antibodies detected. No association with JCV DNA, CMV DNA, EBV DNA, detected by nested PCR, nor HIV antigen p24 was found. These findings show the presence of brain antiganglioside antibodies in the CSF of AIDS patients for the first time. However, the findings do not suggest relating the presence of these antibodies to HIV encephalopathy or particular viral agents, but indicate that the antibodies are detectable in subjects with progressive encephalopathy with a diffuse demyelination.

Cytomegalovirus encephalitis in two patients with AIDS receiving ganciclovir for cytomegalovirus retinitis

Cytomegalovirus (CMV) encephalitis has been reported with increasing frequency in patients with AIDS. Nevertheless, the management of CMV-related encephalitis appears to be problematic and data in the literature on the clinical efficacy of ganciclovir therapy is sparse and controversial. We describe two patients with AIDS who developed CMV encephalitis while receiving ganciclovir maintenance therapy for CMV retinitis. Moreover, there was no improvement in neurological status or virological and radiological response during a further induction course of ganciclovir. These observations suggest that the currently recommended therapeutic protocols with ganciclovir are not effective in the prevention and treatment of CMV encephalitis in patients with AIDS.

High cerebrospinal fluid and serum levels of tumor necrosis factor-alpha in asymptomatic HIV-1 seropositive individuals. Correlation with interleukin-2 and soluble IL-2 receptor

The relationship between tumour necrosis factor-alpha (TNF-alpha) and the interleukin-2 (ILL-2) system in HIV-1 infection is important in understanding the dynamics of early immune response before the development of acquired immunodeficiency syndrome. Levels of TNF-alpha, IL-2 and soluble IL-2 receptor (sIL-2R) in serum and cerebrospinal fluid (CSF) samples from 31 asymptomatic HIV-1 seropositive individuals were measured. High levels of TNF-alpha were detected in CSF of 17 (55%) and serum of 22 (71%) subjects, 15 (88%) of whom had elevated CSF IL-2 levels and 16 (94%) had high sIL-2R levels. Moreover, CSF levels of TNF-alpha significantly correlated with CSF levels of IL-2 and sIL-2R. TNF-alpha, IL-2 and sIL-2R seem to be released within the intrathecal compartment early in the course of HIV-1 infection. In view of the known cytotoxic effects of TNF-alpha, an early release may contribute to subsequent development of neurological complications.

Carnitine depletion in peripheral blood mononuclear cells from patients with AIDS: effect of oral L-carnitine

OBJECTIVE

Reduced levels of serum carnitines (3-hydroxy-4-N-trimethyl-ammonio-butanoate) are found in most patients treated with zidovudine. However, since serum carnitines do not strictly reflect cellular concentrations we examined whether a carnitine depletion could be found in peripheral blood mononuclear cells (PBMC) from AIDS patients with normal serum carnitine levels. In addition, we explored whether it was possible to relate the host's immunoreactivity to the content of carnitine in PBMC and whether carnitine levels can be corrected by oral supplementation of L-carnitine.

DESIGN

Immunopharmacologic study.

METHODS

Twenty male patients with advanced AIDS (Centers for Disease Control and Prevention stage IVCI) and normal serum levels of carnitines were enrolled. Patients were randomly assigned to receive either L-carnitine (6 g/day) or placebo for 2 weeks. At baseline and at the end of the trial, we measured carnitines in both sera and PBMC, serum triglycerides, CD4 cell counts, and the frequency of cells entering the S and G2-M phases of cell cycle following mitogen stimulation.

RESULTS

Concentrations of total carnitine in PBMC from AIDS patients was lower than in healthy controls. A significant trend towards the restoration of appropriate intracellular carnitine levels was found in patients treated with high-dose L-carnitine and was associated with an increased frequency of S and G2-M cells following mitogen stimulation. Furthermore, at the end of the trial we found a strong reduction in serum triglycerides in the L-carnitine group compared with baseline levels.

CONCLUSIONS

Our data indicate that carnitine deficiency occurs in PBMC from patients with advanced AIDS, despite normal serum concentrations. The increase in cellular carnitine content strongly improved lymphocyte proliferative responsiveness to mitogens. Because carnitine status is an important contributing factor to immune function in patients with advanced AIDS, we therefore believe that L-carnitine supplementation could have a role as a complementary therapy for HIV-infected individuals.

Intrathecal synthesis of interleukin-2 and soluble IL-2 receptor in asymptomatic HIV-1 seropositive individuals. Correlation with local production of specific IgM and IgG antibodies

The relationship between the interleukin-2 (IL-2) system and the humoral response against human immunodeficiency virus type-I (HIV-1) is important in understanding the immune reaction before the development of AIDS. Levels of IL-2 and soluble IL-2 receptor (sIL-2R) in serum and cerebrospinal fluid (CSF) samples from 31 asymptomatic HIV-1 seropositive individuals were measured and correlated with levels of anti-1 IgG and IgM antibodies. High IL-2 levels were detected in the CSF of 20 (65%) subjects, 18 (90%) of whom had evidence of intrathecal synthesis of HIV-1-specific IgM antibodies. Similarly, IgG antibodies were detected in 10 subjects who had elevated IL-2 levels in the CSF. Moreover, intrathecal levels of IL-2 and sIL-2R correlated with intrathecal synthesis of both IgG and IgM antibodies. Local release of IL-2 seems to play an important role in the initiation of the antibody response against HIV-1 in early stages of infection and may be utilised in devising effective therapeutic strategies.

Evaluation of vaginal microflora in patients infected with HIV

HIV infection is thought to exacerbate the virulence of normal saprophytic vaginal microflora. We studied the vaginal ecosystem of HIV patients to detect the quantitative and qualitative variation of vaginal microorganisms. 15 patients (5 with AIDS and 10 with ARC) were investigated. Vaginal candidiasis was more frequent in this group than in the control groups. Gardnerella was present in 60% of patients generally in association with anaerobic bacteria and Mycoplasma. Among anaerobia, Bacteroides sp and other Gram-negative rods were the most common bacteria. Neisseria gonorrhoeae was absent in all patients tested. Chlamydia trachomatis was recovered in two out of the 15 HIV-positive patients. Aerobic Gram-negative flora was 100-fold that of the control group and anaerobic Gram-negative flora 10-fold.

Clinical results of a multicenter study with sulbactam/ampicillin for the treatment of patients with lower respiratory and urinary tract infections

A total of 124 patients with lower respiratory tract (44) or urinary tract infections (80) were enrolled in an open, multicenter study to evaluate the efficacy and tolerability of sulbactam/ampicillin, administered at the dosage of 3 g/die by intramuscular route. Pretreatment pathogens from patients with lower respiratory tract infections included: Streptococcus alpha-haemolyticus in 8 cases, Streptococcus beta-haemolyticus in 2 cases, Staphylococcus albus in 7 cases, Haemophilus influenzae in 7 cases, Staphylococcus aureus in 6 cases, Klebsiella oxytoca in 5 cases, Staphylococcus epidermidis in 3 cases, Streptococcus pneumoniae in 3 cases, Escherichia coli in 2 cases; in one subject (2.75%), no microorganisms were isolated. In vitro, 36 isolates (84%) were sensitive to SA and 7 (16%) were resistant. At the end of therapy, all the causative pathogens sensitive to sulbactam/ampicillin were eliminated. In patients with urinary tract infections, pretreatment pathogens were: E. coli in 40 cases, S. albus in 16 cases, Proteus mirabilis in 8 cases, Enterobacter agglomerans in 6 cases, Proteus vulgaris in 3 cases, Streptococcus faecalis in 3 cases, Streptococcus liquefaciens in 2 cases, Pseudomonas aeruginosa in 2 cases. In vitro, 64 isolates (80%) were sensitive to sulbactam/ampicillin and 16 (20%) were resistant. At the end of therapy, 63 out of the 64 pathogens sensitive to sulbactam/ampicillin were eliminated; in one case the therapy was interrupted due to adverse effect. Clinical efficacy: in subjects with lower respiratory tract infections, sulbactam/ampicillin cured 32 patients (72.72%) and ameliorated the clinical status of 8 patients (18.18%); efficacy rate: 90.9%).(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar cell population in HIV infected patients

Alveolar lymphocytosis, in the face of blood lymphopenia, is a common finding among patients with AIDS. We studied by bronchoalveolar lavage (BAL), the alveolar cell profile of 43 human immuno deficiency virus (HIV) seropositive patients divided into three groups involving the advanced stages of the disease: group A (n = 9; CDC III), ambulatory individuals without systemic or respiratory symptoms; group B (n = 15; CDC IV) patients admitted for evaluation of fever of unknown origin (FUO) without pulmonary involvement; group C (n = 19; CDC IV), patients admitted for evaluation of an acute pulmonary condition. Sex, age and risk factor were comparable among the groups. Alveolar lymphocytosis was found in no group A patients, in 2 out of 15 group B patients (both with P. carinii lung infection) and in all group C patients, where pulmonary involvement was due to opportunistic infection or to nonspecific interstitial pneumonitis. Our findings suggest that in patients with advanced HIV infection alveolar lymphocytosis may be an expression of a concomitant process within the lungs either clinically manifest or inapparent, or possibly related to HIV primary lung involvement.

Alveolar cell population in HIV infected patients

Alveolar lymphocytosis, in the face of blood lymphopenia, is a common finding among patients with AIDS. We studied by bronchoalveolar lavage (BAL), the alveolar cell profile of 43 human immuno deficiency virus (HIV) seropositive patients divided into three groups involving the advanced stages of the disease: group A (n = 9; CDC III), ambulatory individuals without systemic or respiratory symptoms; group B (n = 15; CDC IV) patients admitted for evaluation of fever of unknown origin (FUO) without pulmonary involvement; group C (n = 19; CDC IV), patients admitted for evaluation of an acute pulmonary condition. Sex, age and risk factor were comparable among the groups. Alveolar lymphocytosis was found in no group A patients, in 2 out of 15 group B patients (both with P. carinii lung infection) and in all group C patients, where pulmonary involvement was due to opportunistic infection or to nonspecific interstitial pneumonitis. Our findings suggest that in patients with advanced HIV infection alveolar lymphocytosis may be an expression of a concomitant process within the lungs either clinically manifest or inapparent, or possibly related to HIV primary lung involvement.

Serum selenium concentration and disease progress in patients with HIV infection

The selenium concentration in the serum of 67 patients with HIV infection was measured to determine whether selenium deficiency occurred in the different stages of the disease. In the first stage of the study, patients were divided into four groups: symptom-free subjects, PGL (persistent generalized lymphadenopathy), ARC (AIDS related complex), and AIDS (acquired immunodeficiency syndrome). Selenium concentrations were normal in HIV antibody positive symptom-free subjects (1.18 +/- 0.27 mumol/L) and lower than normal in the other three groups (p less than 0.001). There was a significant correlation (p less than 0.001) between selenium levels and values of hemoglobin and erythrocyte sedimentation rate. Selenium deficiency was in no case associated with a lack of zinc in serum (also determined in all patients). In the second stage of the study, 12 patients were treated for a period of two months with low doses of selenium to assess whether such supplementation was able to restore their impaired immunological and hematological functions. The therapy increased serum selenium concentrations (from 0.77 +/- 0.23 to 1.44 +/- 0.41 mumol/L) and symptomatic improvements were noted. However, no changes were observed in the immunological and hematological parameters.

HBV and HIV expression in lymph nodes of HIV positive LAS patients: histology and in situ hybridization

The presence of hepatitis B virus (HBV) and human immunodeficiency virus (HIV) was investigated using hybridization in 15 lymph nodes and one Kaposi's sarcoma skin lesion obtained from HIV-positive patients. Cryostat tissue sections were hybridized with chemically modified DNA probes for HBV and HIV. HIV genome was mainly observed in the cytoplasm of cells present in 7/15 lymph nodes and in the Kaposi's sarcoma skin lesion, thus indicating the expression of HIV replication. Control samples hybridized with an HTLV I probe were negative. HBV genome was found in the cytoplasm of lymphoid mononuclear cells in 2/7 lymph nodes, obtained from HIV+ patients without serum markers of ongoing HBV infection. Lymph node positivity for HBV DNA also confirms that lymphoid cells may be a target for HBV. Since HBV infection seems to precede HIV infection in nearly all patients, it is possible that it may represent a factor facilitating the development of the HIV-related disease.

Spectrum of HIV infection and AIDS in a cohort of Italian hemophiliacs

A group of 173 subjects affected by congenital clotting factor deficiencies was evaluated with regard to the impact of HIV infection. On the whole, 78 patients (45%) were found to be HIV Ab-positive. As of March, 1988, of the seropositive patients, 63 (80.8%) had an asymptomatic HIV infection (Group II/CDC), three (3.8%) had a persistent generalized lymphadenopathy (Group III/CDC). The 12 (15.4%) remaining patients could be classified in Group IV of the CDC classification due to their symptoms and signs; in particular, 10 came under surveillance case definition for AIDS. Assay for the HIV antigen was positive in 14 (17.9%) seropositive hemophiliacs. With regard to the immunological features, our data clearly show that a sharp decline in the number of CD4+ cells was associated with symptomatic forms of the disease. An evaluation of the time elapsed from seroconversion to the appearance of the symptomatic clinical condition showed an average incubation of 37 months.

Influence of methisoprinol (isoprinosine) on HIV-infected human lymphocytes: in vitro immunological, virological, and ultrastructural studies

Methisoprinol (isoprinosine) is a synthetic compound with reported antiviral and immunomodulating properties. Results of the present study showed that methisoprinol at concentrations greater than or equal to 200 micrograms/ml reduces the p24 and gp120 viral antigen expression on the surface of human immunodeficiency virus (HIV)-infected lymphocytes and the reverse transcriptase levels. In addition, cell viability, the number of the CD4+ cells, and the CD4+/CD8+ cell ratio are higher in methisoprinol-pretreated cell suspensions than in untreated HIV-infected cell cultures. A quantitative freeze-fracture study on the density of the intramembranous particles (IMP) present on both fracture faces of the plasma membrane of lymphocytes has shown that pretreatment with methisoprinol induces a different molecular organization resulting in a nearly three times increase of IMP density.

Pharmacokinetics of zidovudine and concomitant inosine-pranobex in AIDS patients

3'-azido-3'-deoxythymidine (AZT) was administered orally to 8 AIDS patients at a dose of 100 mg every 6 hours for 14 days. On days 8 - 14 the patients were also given 1 g inosine-pranobex (INPX) every 6 hours. On day 7, while the subjects were taking AZT alone and on day 14 while they were receiving AZT + INPX, blood samples were obtained over a 6-hour dosing interval for measurement of AZT by a specific AZT radioimmunoassay. AZT levels on day 14 were significantly higher than the corresponding levels on day 7, resulting in a 2-fold increase of the area under the serum concentration-time curve (AUC) and a prolongation of the mean half-life of AZT (44 to 70 min) during the INPX treatment. INPX is an immunomodulatory drug with an inhibitory effect on HIV. The potential advantages of a combined treatment AZT + INPX are: 1) need for lower dose of AZT for maintaining a therapeutic anti-retroviral level; 2) a longer interval period between AZT treatments; 3) a potential to enhance immunological response resulting from INPX treatment; 4) reduced costs of care for patients.

In situ hybridization of human immunodeficiency virus (HTLV-III) in cryostat sections of lymph nodes of lymphadenopathy syndrome patients

The presence of human immunodeficiency virus (HIV, or HTLV-III) genome sequence was investigated by means of in situ hybridization in cryostat sections of lymph nodes from lymphadenopathy syndrome (LAS) patients. The technique employed involved the modification of the DNA probe by chemical insertion of an antigenic sulfone group in cytosine moieties and the visualization of DNA by a double-antibody immunohistochemical reaction. The hybrid formation was revealed in five out of ten cases: in all positive samples, HIV was mainly observed in the cytoplasm of lymph node cells. The method of in situ hybridization described in the present paper is specific and has some advantages if compared with other techniques based on the use of DNA probes labelled with radioisotopes or biotin by nick translation.

Ofloxacin: clinical evaluation in urinary and respiratory infections

40 patients with urinary tract (30 cases) or pulmonary infections (ten cases) caused by different agents were treated with ofloxacin in order to evaluate the efficacy and safety of this new quinolone derivative. Treatment was performed with a dose of 300 mg three times a day for nine to 26 days. Out of the 30 urinary tract infections, 22 were clinically and bacteriologically cured, six had a clinical improvement but the causative organism persisted, one suffered a reinfection with a different pathogen and one failed to respond. Clinical and bacteriological cure was achieved in eight of the ten pulmonary infections. The overall clinical response for the two groups of patients was 97% (cure and improvement): bacteriological cure was achieved in 75% of the patients treated. No serious side effects of ofloxacin therapy were observed in any of our patients.

Assessment of immunomodulating activity of ofloxacin and three other quinolones in human plasma

A time-dependent degree of immunosuppression or immunostimulation which may be correlated to pharmacokinetic variables was obtained by administering a single dose of ofloxacin, norfloxacin, pipemidic and piromidic acid to healthy volunteers. The plasma samples collected before drug administration and then at various time intervals were tested for their immunomodifying activity by employing a modified 2-way mixed lymphocyte reaction and a PMN chemotactic assay. Our results show that some of the quinolones tested--norfloxacin, pipemidic acid, piromidic acid--have an immunosuppressive activity.

Influence of ofloxacin on murine Peyer's patch lymphocytes

Several factors must be considered before the clinical impact of antimicrobials on the immune function can be determined. No data are available as yet on the influence of ofloxacin, a new fluoro-quinolone, on the lymphocytes of Peyer's patches. The present study offers evidence that murine Peyer's patches are influenced by ofloxacin administered by the oral route for seven days (15 mg/kg). No modifications of the percentage of the Thy 1,2 and SIg positive splenocytes and of the PHA and LPS-induced proliferative responses were observed studying cell suspensions from the spleen of the same animals. An immunotoxic effect of the compound on the cells of Peyer's patches or an impairment of their homing tendency has been postulated.

Human eosinophil heterogeneity

The aim of this review is to examine some of the most important findings pointing toward human eosinophil heterogeneity. Special importance is given to cell density, surface receptors, metabolism and response to biological products or synthetic compounds.

Influence of ofloxacin, norfloxacin, nalidixic acid, pyromidic acid and pipemidic acid on human gamma-interferon production and blastogenesis

Several new quinolone derivatives were investigated for their influence on human lymphocyte blastogenesis and gamma-interferon production following concanavalin A stimulation. All the antimicrobials induced inhibition of lymphocyte DNA synthesis. The gamma-interferon measurements showed that nalidixic acid and norfloxacin have a negative influence on lymphokine production and release.

Human eosinophils and parasitic diseases--III. Beta-interferon increases eosinophil IgG-Fc receptor expression and capacity

Eosinophilic granulocytes from the blood of patients with parasitic diseases were preincubated in the presence or absence of beta-interferon (beta-IFN). The number of cells bearing IgG-Fc receptors was determined by rosette formation with chicken erythrocytes coated with IgG antibodies. beta-IFN augmented the expression of IgG-Fc receptors on the cells within 1 h incubation. Treatment of beta-IFN with heat or acid did not abolish the activity. The doses of beta-IFN needed to induce the modulations of IgG-Fc receptors could also augment the eosinophil-mediated antibody-dependent cytotoxicity (ADCC) against chicken red blood cells which resulted most pronounced when the IgG antibodies were present in suboptimal amount. These data suggest the role of beta-IFN in the host resistance to parasitic diseases, mainly in the initial phases of parasitic infestation when the specific IgG antibody levels are very low.

Eosinophil-mediated cellular cytotoxicity induced by zymosan-activated serum

The aim of the present work was to develop an in vitro model of eosinophil cytotoxicity which mimics numerous in vivo situations characterized by complement activation through the alternative pathway. Our results demonstrate that eosinophilic granulocytes from patients with parasitic diseases and blood eosinophilia were able to damage chicken red blood cells when incubated with zymosan-activated serum (ZAS) as assessed by a 51Cr release assay. The phenomenon was independent of the presence of antibodies directed against the target cells and related to the quantity of ZAS added to the wells. As target cell lysis is totally or partially inhibited by catalase, sodium azide and potassium cyanide, an involvement of toxic oxygen derivatives as cytolytic mediators was suggested.

Human amoebiasis: the interaction of lymphocyte surface-bound immune complexes and PMNs impairs T cell proliferative responses to E. histolytica mitogen

In some of the sera from patients with amoebiasis circulating immune complexes are present which are thought to interact with lymphoid cells, enabling them to elicit a burst of oxygen consumption in PMNs. The intensity of chemiluminescence is related to the presence of C3+ and Fc IgG+ cells in the lymphoid cell suspensions employed. The generation and release of highly reactive oxygen derivatives from PMNs impair T lymphocyte proliferative responses to the E. histolytica mitogen. The Authors suggest that one of the mechanisms by which circulating immune complexes present in the sera of patients with amoebiasis may interfere with T cell-mediated immune responses, is through their binding to the surface of the C3+, Fc IgG+ cells with subsequent stimulation of the PMN oxidative metabolism.

The effect of NPT 15392, 9-(erythro-2-hydroxy-3-nonyl)-6-hydroxypurine, on the phytohemagglutinin of OKT3+, OKT4+, OKT8+, and OKM1+ cell-depleted and undepleted peripheral blood mononuclear cells

NPT 15392, 9-(erythro-2-hydroxy-3-nonyl)-6-hydroxypurine, has been reported to influence immunological responses involving different cell types. Herein data are obtained by studying the influence of NPT 15392 on the phytohemagglutinin (PHA)-induced proliferative responses of unfractionated peripheral blood lymphocytes (PBLs) and of cell suspensions, which have been depleted of the cell subsets recognized by the monoclonal antibodies OKT3, OKT4, OKT8, and OKM1, in an attempt to identify which cell types respond to NPT 15392 in the PHA-driven blast transformation assay. The proliferative responses of unfractionated peripheral blood lymphocytes are potentiated when the drug is employed at the concentration of 0.1 microgram/ml and inhibited when NPT 15392 is added to the cell suspensions at concentrations over 5 micrograms/ml. The data reported here suggest that this phenomenon is a composite effect, made up of a combination of the counteracting effects caused by the OKT4+ cells on the one hand, and the OKT8+ and OKM1+ cells on the other.

Pharmacokinetic assessment of immunosuppressive activity of antibiotics in human plasma by a modification of the mixed lymphocyte reaction

Antibiotics may impair the development and expression of specific or nonspecific immune responses. Prophylactic administration of antibacterial antibiotics is widely used in ICUs. We studied the immunosuppressive activities of cefotaxime, chloramphenicol, gentamicin, metronidazole, and rifamycin as a function of time after the administration of these drugs to ICU patients, finding that the last 4 drugs had an immunosuppressive activity detectable up to 8 h by a mixed lymphocyte reaction. When these antimicrobial agents were added to normal pooled plasma in concentrations similar to those obtained in vivo, a similar degree of inhibition was observed.

Evaluation of automatic antimicrobial susceptibility testing with the MS-2 system

We present the results of sensitivity of 191 Gram-negative bacteria towards the following antibiotics: aminoglycosides (amikacin, gentamicin, tobramycin, netilmicin), cephalosporines (moxalactam, cefotaxime, ceftazidime) and piperacilline obtained by agar diffusion method (Kirby-Bauer) versus automatic system MS 2 Abbott. Essential accord expressed in percentage is for amikacin 96%, for gentamicin 93%, for moxalactam 91%, for tobramycin 95%, for cefotaxime 92%, for piperacilline 89%, for netilmicin 90%, for ceftazidime 92. Full accord gives more discrepant results especially for cephalosporins. For aminoglycosides no significative differences were observed between the two methods. For cephalosporins the incidence of discordance was a little more high. A better sensitivity was obtained by Kirby-Bauer method versus automatic system, which can be considered a therapeutical tool as it furnishes rapidly (4 hours) MIC values, useful to establish antibiotic doses.

[Radial counter-immunoelectrophoresis in the determination of specific anti-hydatidosis antibodies. Preliminary observations]

Radial counter-immunoelectrophoresis was evaluated with sera from surgically-confirmed hydatidosis cases, patients with other parasitic diseases and healthy controls. Radial counter-immunoelectrophoresis was a sensitive as classic counter-immunoelectrophoresis based on the same positivity criterion and was equally specific for the immunodiagnosis of human hydatidosis. The procedure appears to be simple and rapid (the immunoprecipitation step requires just 5 minutes) and merits consideration.

Fractionation and characterization of hydatid fluid antigens with identification of an antigen similar to human serum albumin

Human and sheep hydatid fluids were separated by ultrafiltration, gel chromatography and immunoabsorption into several immunogenic fractions in which both parasite antigens and host substances were present. The immunological characterization of proteic antigens was carried out by immunodiffusion and immunoelectrophoresis with rabbit and ram antisera. A line of identity was observed between a human fraction (labelled as III) and a sheep fraction (labelled as 2B). Further evidence of the presence of a parasitic antigen in fraction III was given by its reaction against an antiserum from ram directed against sheep fraction 2B. The immunological characterization of fraction III indicated a close similarity between human serum albumin and parasitic antigens.

Anti-Ia reactivity in sera from subjects with Entamoeba histolytica infection

Sera from 15 patients with Entamoeba histolytica infection were tested for anti T-cell antibodies by assessing cross-reacting specificities with the antigens defined by an anti-Ia hybridoma antibody. T cells prepared by sheep erythrocyte rosetting were preincubated with the test sera and then with the anti-Ia antibody. Binding of the specific monoclonal antibody was assessed by rosetting with ox erythrocytes conjugated with goat anti-mouse IgG. Eight sera from amoebic patients were found to block the binding of monoclonal mouse hybridoma anti Ia-antibody to T cells. Blocking of anti-Ia binding was not due to Fc IgG receptor binding by immune complexes nor was it HLA-DR restricted. T cells pre-treatment with the amoebic sera positive for anti-Ia activity showed reduced activity when tested in the autologous mixed lymphocyte reaction (AMLR). The results of our study seem to suggest the existence of specific anomalies of immunoregulation during E. histolytica infection which may play a role in inducing immune disregulation in vivo.

Detection and partial characterization of circulating immune complexes in hydatid disease

Thirty sera from eight patients with disseminated or localized hydatid disease have been examined for the presence of circulating immune complexes (CICs) by the conglutinin-binding assay and for immunoglobulin levels. The highest levels of CICs were of the immunoglobulin A (IgA) class, with lower values of IgG-CIC and IgM-CIC; these results did not correlate, except for IgG, with the free immunoglobulin levels. Efforts to identify parasitic antigen(s) involved in the CIC formation with different methods have been unsuccessful. In the follow-up of each patient, CIC appeared to be better correlated to clinical conditions than to hemagglutination titers. We have concluded that the presence of CIC in hydatid disease is probably an expression of B-cell polyclonal activation and that these complexes are valuable in the clinical monitoring of the disease.

LDH isoenzyme distribution in human eosinophils

The lactate dehydrogenase (LDH) isoenzyme pattern has been determined in human eosinophils isolated from the peripheral blood of healthy donors and patients with parasitic diseases. Almost equal LDH1 and LDH5 values appear to be a characteristic of the eosinophils obtained from healthy subjects. Eosinophilic granulocytes which have been isolated from the peripheral blood of patients with eosinophilia due to parasitic infestations have reduced values of LDH5 accompanied by higher LDH1 as compared with eosinophils from healthy donors. Centrifugation of cells through multiple discontinuous gradients of polyvinylpyrrolidone-coated silica particles made it possible to isolate distinct eosinophil subpopulations of differing densities which showed differences in cell surface markers, K-cell activity and also LDH patterns. Analysis of the lactate dehydrogenase isoenzyme patterns showed that EAG+ and EAC+ eosinophilic leukocytes are characterized by very low values of LDH5.

Human peripheral eosinophils with receptors for IgM: demonstration and ultrastructural morphology

Receptors for IgM were detected on peripheral blood human eosinophils by a rosette technique with ox red blood cells coated with the IgM fraction of the specific immunserum. Between 14% and 43% (mean 27%) FcmuR positive cells were found after an overnight incubation period at 37 degrees C by using this technique. The specificity of the receptors for IgM was assessed by studying the inhibitory capacity of purified human IgM in the rosette assay. From an ultrastructural point of view, the EAM rosette-forming cells are mature eosinophilic granulocytes characterized by a nucleus with a variable number of lobes and a certain number of "first type" granules partially or totally devoid of their content.