CD34-expressing human thymocyte precursors proliferate in response to interleukin-7 but have lost myeloid differentiation potential

CD34 is a marker for pluripotent stem cells also present on lineage-committed hematopoietic progenitors from bone marrow and a subpopulation of immature thymocytes. To characterize these early immature thymocytes, we have studied 24 pediatric thymus samples for CD34/7 expression. Three subpopulations could be defined from these T-cell receptor (TcR-) immature thymocytes: CD34+7++ (12.0 +/- 5.8), CD34-7++ (12.6 +/- 8.6), and CD34-7+ (71.5 +/- 17.0%). CD7++ represents upregulation of this antigen and is expressed by cells of a blast-like morphology. Three-color flow cytometric analysis of these three subsets suggests the following ordered differentiation sequence: CD34+7++1-4-8-45RA+-->CD34+7++1+ 4+8-45RA+/- -->CD34-7++1+4+8-+45RO+-->CD34-7+1++4+8+45RO+. Early immature thymocyte cell division is essential in the thymus to generate a large number of precursors before the initiation of the selection process. We observed that both CD2 as well CD28 activation pathways were inefficient to serve as costimulant with phorbol ester 12-O-tetradecanoyl phorbol 13-acetate or interleukin-2 (IL-2) to induce the proliferation of the three CD34/7 subsets isolated by cell sorting. However, whereas IL-1, IL-2, IL-3, IL-4, granulocyte colony-stimulating factor, and granulocyte-macrophage colony-stimulating factor were ineffective, IL-7 was a potent cytokine, alone or in synergy with stem cell factor (SCF) to induce immature thymocyte proliferation. The proliferation induced by IL-7 or IL-7 + SCF is restricted to the CD34+ cells and, after 4 or 8 days of culture with IL-7, some CD34+7++ acquire the expression of CD4 and/or CD8, but remain CD3/TcR-. We also tested the myeloid differentiation capacity of these CD34 immature thymocytes. Using two different approaches, myeloid colony formation in methylcellulose and limiting dilution analysis in the presence of myeloid growth factors, we were unable to detect myeloid differentiation capacity from CD34+ early thymocytes, whereas CD34+7+ from bone marrow contained about 10% of the clonogenic cells present in the CD34+7- fraction. Together, these data support the concept that thymic CD34+7++ represents the earliest thymic subset of fully committed T-lineage cells, capable of proliferating specifically to IL-7.

Post-transfusional anti-HCV-negative, non-A, non-B hepatitis. (I) a prospective clinical and epidemiological survey

Despite the identification of hepatitis C virus (HCV) and the detection of anti-HCV antibodies in the serum of infected individuals, a sizeable proportion of patients who develop transfusion-associated acute non-A, non-B hepatitis following surgery do not develop anti-HCV antibodies. The cause of this disease remains unknown. To assess the role of homologous blood transfusion in anti-HCV-positive and -negative, non-A, non-B hepatitis following surgery, patients receiving homologous blood, autologous blood alone, or no transfusions were prospectively studied. Consumption of potentially hepatotoxic drugs was also quantified. Anti-HCV antibodies were tested retrospectively when commercial assays became available. Of the 181 patients who received homologous blood which tested negative for surrogate markers of infectivity, 19 (10.5%) developed non-A, non-B hepatitis, associated with anti-HCV seroconversion in three cases. Of the 90 autologous blood recipients, non-A, non-B hepatitis developed in one (1.1%), who did not seroconvert to anti-HCV. Of the 64 untransfused patients, non-A, non-B hepatitis developed in one (1.6%), who was anti-HCV-positive before surgery. Logistic regression analysis showed that the occurrence of non-A, non-B hepatitis was associated with homologous blood transfusion, but not with the consumption of potentially hepatotoxic drugs. The 16 homologous-blood recipients who developed anti-HCV-negative, non-A, non-B hepatitis had received blood from 70 donors, none of whom had detectable anti-HCV antibodies but six of whom had minimal elevations of serum aminotransferase activity. Anti-HCV-negative, non-A, non-B hepatitis is mainly transfusion-transmitted in the surgical setting. Known hepatotropic agents may be involved despite the absence of usual serum markers, but our results are also consistent with the involvement of an unidentified non-A, non-B, non-C agent.

[Allergy to cockroaches in a Swiss population with asthma and chronic rhinitis]

Cockroach extracts are known to contain powerful allergens. In some parts of the world the majority of asthmatics have been shown to be allergic to cockroaches. We have evaluated the prevalence of sensitization to the cockroaches Blattella germanica and Trogoderma angustum in a Swiss population with chronic, non-seasonal asthma and rhinitis. The sera of 110 patients were screened for specific IgE by the RAST technique. We found 10 positive RAST (class 1 to 2). 7 of the 110 patients were sensitized to cockroaches (6.3%). 3 patients had positive RASTs for both species of cockroach. 2 patients had no other detectable allergy (= 5% of those who were considered as non-allergic before the study). These results suggest that allergy to cockroaches is uncommon in Switzerland but can sometimes be detected. We conclude that in Switzerland, screening for hypersensitivity to cockroaches should not be included in routine allergic investigations.

Clinical and microbiologic features of urethritis in men in Toulouse, France

On hundred twenty-six men who attended a hospital microbiology laboratory and 99 men who attended a private laboratory in Toulouse, France, for symptoms of urethritis were examined during 1988, for evidence of urethral pathogens. The following incidences were found: Neisseria gonorrhoeae: 24 (10.7%); Chlamydia trachomatis: 58 (25.8%); Ureaplasma urealyticum: 46 (20.4%); Gardnerella vaginalis: 21 (9.3%); Haemophilus parainfluenzae: 21 (9.3%); Streptococcus agalactiae: 15 (6.7%); Candida albicans: 10 (4.4%); and Trichomonas vaginalis: 4 (1.8%). The prevalence of these microorganisms was similar in the two groups of patients. No pathogen was isolated from 71 patients (31.6%). Mixed infections with at least two pathogens were found in 49 men (21.8%). Another goal of this study was to determine the relative prevalence of urethral pathogens in relation to clinical findings. N. gonorrhoeae was isolated significantly more often in patients who had a urethral discharge (P less than .05) that contained five or more polymorphonuclear cells per high-power field (PMN/HPF) (P less than .001). G. vaginalis was isolated significantly more often in patients who did not have an urethral discharge (P less than .05) and in men with less than five PMN/HPF (P less than .05). Isolation of C. albicans was significantly associated with pruritus (P less than .05) and balanitis (P less than .001). Like the clinical features, the gram-stained urethral smear was of limited value in diagnosis and therapeutic decision-making regarding non-gonococcal urethritis. In contrast, this study underlines the importance of full identification of urethral isolates in the management of urethritis in men.

Ceftriaxone plus amikacin in neutropenic patients: a report on 100 cases

100 febrile patients with chemotherapy-induced neutropenia (less than 0.5 x 10(9)/l) were empirically treated by ceftriaxone (2 g daily in adults, 50 mg/kg daily in children, as a once daily injection) and amikacin (15-20 mg/kg daily). The mean age was 41 years (range 8-72). 51 patients had acute leukemia, 29 non-Hodgkin's lymphoma, 12 Hodgkin's disease, 8 other disorders. 23 febrile episodes were bacteriologically documented (gram-positive: 13 patients; gram-negative: 8 patients; Candida: 2 patients) including 13 cases of bacteremia; 10 were clinically documented, and 67 remained of undetermined origin. Apyrexia was obtained in 39 patients by ceftriaxone plus amikacin alone (success), in 36 patients after the addition of vancomycin and/or amphotericin B (improvement), whereas in the remaining 25 patients it was necessary to substitute the study drug. The failure rate was correlated to the duration of neutropenia: 0/13 when neutropenia less than 6 days; 3/41 (7%) when 6-10 days; 22/46 (48%) when greater than 10 days. Only 2/20 (10%) of patients with neutropenia greater than 20 days were treated with ceftriaxone plus amikacin alone. 9 of the 23 bacteriologically documented episodes were successes (including 6 of the 11 cases due to Staphylococcus), 7 were improvements and 7 were failures (including the 3 cases due to Pseudomonas). No side effects were seen. Ceftriaxone plus amikacin is an effective firstline antibiotic combination in the treatment of febrile neutropenic patients.

Proliferation of early human myeloid precursors induced by interleukin-1 and recombinant soluble CD23

Low affinity Fc epsilon receptors (Fc epsilon RII/CD23) or their soluble fragments have various biologic effects on B- and T-cell lineages. In this study, we have assessed the effect of recombinant soluble CD23 (rsCD23) on the proliferation of human bone marrow (BM)-derived myeloid precursors with or without recombinant interleukin-1 (rIL-1) addition. Non-adherent CD2- or CD34+ BM cell subsets were used as target cells. Our results show that rsCD23 in synergy with rIL-1 displays an interleukin-3-like activity as it promotes the proliferation of multipotential marrow precursors. This effect was abolished by anti-CD23 addition to these cultures, but was not affected by anti-IL-3 monoclonal antibody. Furthermore, sequential study indicates that rIL-1 induces bone marrow cell responsiveness to rsCD23.

Stage specific phosphoinositides turnover capacity of human intrathymic T cells following CD2-triggering

Triggering of distinct CD2 epitopes on human T lymphocytes increases their phosphatidylinositol (PI) cycle-related metabolism. In this work, we investigated the relationship between this signal transduction pathway following surface CD2 antigen triggering and intrathymic T cell development. Therefore, various thymocyte subsets were incubated with co-mitogenic CD2I+III mAb. The cells were then tested for their various phosphoinositides levels as well as their ability to proliferate in response to recombinant interleukin-2 (rIL-2). Our results indicate that immature CD4- CD8- cells have high PI metabolism while more mature CD4+CD8+ and unfractionated thymocytes display significantly lower PI-turnover. Mature CD4+CD8- and CD4-CD8+ thymocytes regain this transduction capacity. Thus, PI-turnover following CD2- triggering is linked to the developmental fate of thymocyte subclasses.

Ambulatory computer system for recording and controlling locomotion

Description of an original miniature computer system capable of recording biomechanical parameters during locomotion, providing auditory signals which can be used in biofeedback locomotor learning, and triggering functional electrical stimulation of nerves and muscles at preselected moments in the locomotor cycle. The system, which is worn on the patient's back, is connected to appropriate gauges with which it is possible to measure knee angle and to record the time of heel contact with the ground. The relevant data are stored in the system memory and can be transferred to a microcassette and later displayed as a function of time on a video screen or printed on paper. The same data can be used on-line to provide a patient with a sound signal as a basis for biofeedback training. This kind of training has been successfully used to correct knee hyperextension during locomotion in hemiplegic patients. The system can also be used to trigger a stimulator and thus constitutes a valuable tool for investigations and treatments involving functional electrical stimulation. Many other applications may be developed, both in basic research and in various fields where motor training is required.

Phenotypic heterogeneity of B- and T-cell differentiation antigens in B-CLL

Peripheral blood from 38 B-CLL patients was studied by flow cytometry with 25 clustered or non-clustered monoclonal antibodies (moAbs) in order to characterize the cell surface phenotype of lymphoid cells. All moAbs chosen detected B or CD1-8 T-cell differentiation antigens or MHC class II antigens. The results showed a heterogeneity in the leukemic cell reactivity with the various moAbs and between patients. The restricted B-cell antigens recognized by BL14, Y2955 and anti-class II moAbs were constantly expressed in leukemic cells, while B-cell antigens reacting with FMC7 and BL13 moAbs were variably detected. In addition to CD5 antigens, other T-cell markers, including several epitopes of the CD1 group, were also found to be present on the leukemic cell surface in several cases. The relationship between the various clinical and/or biological features of the disease and the cell surface phenotype was studied. Our results indicated a correlation between the lymphoid cell reactivity with M241 (CD1) and BL13 (CD21) and the severity of the disease.

Lower genital tract infections in women: comparison of clinical and epidemiologic findings with microbiology

We screened 392 women attending the Laboratory of Microbiology of Toulouse Purpan Hospital for symptoms of lower genital tract infection for six microorganisms. Rates of isolation of Neisseria gonorrhoeae, Chlamydia trachomatis, Candida albicans, Mycoplasma hominis, and Gardnerella vaginalis were 1%, 7.7%, 29.8%, 23.8%, and 37.5%, respectively. Trichomonas vaginalis was detected by direct examination in specimens from 3.1% of patients. Another goal of this study was to determine the relative prevalence of these microorganisms in relation to clinical and epidemiologic findings. C. trachomatis was isolated significantly more often from patients under 25 year old (P less than 0.001), from those who use oral contraceptives (P less than 0.01), from those who have a male sexual partner with symptoms of sexually transmitted disease (P less than 0.001), and from those who present signs of cervicitis (P less than 0.05). Isolation of C. albicans was significantly associated with vulvar pruritus (P less than 0.01), vulvitis (P less than 0.01), and vaginitis (P less than 0.001). G. vaginalis and M. hominis are significantly associated with bacterial vaginosis (P less than 0.001). This syndrome was diagnosed clinically in 27.2% of our study population and was highly correlated with use of an intrauterine device (P less than 0.05).

A T chronic lymphocytic leukemia with large granular lymphocytes. Phenotype and functions of leukemic cells under in vitro treatment by differentiation inducers

We reported the morphologic, phenotypic and functional characteristics of leukemic cells with natural killer (NK) properties in a case of T chronic lymphocytic leukemia with large granular lymphocytes. These cells were cytologically and cytochemically characterized as phosphatase acid positive large granular lymphocytes (LGL), and presented parallel tubular arrays at the ultra structural level. They displayed a CD2, CD3, CD8, CD11, Leu 7, and Leu 11 positive phenotype while they lacked B cell markers including surface immunoglobulins. In addition, they expressed human leukocyte antigens (HLA) Class I, but no Class II antigens. These phenotypic studies were also performed after cells were cultured in vitro with 12-0-tetradecanoyl phorbol 13-acetate, gamma interferon, 5-azacytidine, sodium butyrate, phytohemagglutinin, and interleukin 2 (IL2). The cell surface markers underwent several significant changes. Among them we noted a higher percentage of labeled cells with anti-CD6 and CD7 monoclonal antibodies (moAbs), and a positivity with an anti-CD19 (B4) moAb. The leukemic LGL spontaneously developed a NK activity on K 562 tumor cells, which was not affected under the various T and B cells growth factors because they became more sensitive to IL2; but they were also stimulated by a 50-kilodalton (KD) B cell growth factor (BCGF) factor devoid of any T cell proliferation activity. Together these results gave a better characterization of azurophilic granules containing T chronic lymphocytic leukemia, and enabled the documentation of the differentiation of LGL with NK activity.

Sickness absence at the French National Electric and Gas Company

The certified sickness absence of workers in the French National Electric and Gas Company was studied for 12 months and has been described according to the demographic and occupational characteristics of the employees. The results showed that the principal factors affecting absence are sex, job, and salary. The high percentage of absent women was explained by neither the type of occupation nor family status. Respiratory diseases, accidents, and musculoskeletal and psychiatric disorders were the leading diagnostic categories. Indices of severity, duration, and frequency were calculated and compared between groups. The duration of absence increased with the severity of the medical cause of absence and with the patient's age.

CD 1-8 antigens on human diphtheria toxoid T lymphocyte clones: expression and modulation by TPA, sodium butyrate, and 5-azacytidine

The modulation of antigen expression on the surface of TLC by different differentiation inducers as well as the inhibition of the TLC proliferative response by specific MoAbs may lead to a clarification of the role of various surface molecules studied in antigen-specific T-cell response. We investigated the expression of CD 1-8 antigens on the surface of diphtheria toxoid or varidase specific TLC with a series of MoAb. CD1 and CD8 antigens were not expressed on the proliferative TLC. CD2, CD3, CD4, and CD5 antigens were homogeneously expressed on all TLC in contrast to CD6 and CD7 antigens which were present on only a fraction of the cells in a given TLC. In functional assays, anti-CD2, anti-DR VI-15C, and anti-CD25 MoAbs blocked the proliferative response to DT and anti-CD3, anti-CD4, anti-D44 MoAbs had intermediate inhibition effects. Anti-CD5, anti-CD6, and anti-CD7 MoAbs did not inhibit the proliferative response. Surface marker analysis revealed that the expression of CD2 to CD7 antigens (and also CD25) may be modified following incubation of the TLC with TPA or sodium butyrate but not with 5-azacytidine. TPA greatly decreased the expression of CD3 and CD4 antigens after a 6-hr exposure. Preincubation of TLC cells with TPA inhibited the mitogenic effect of anti-CD3 MoAbs on TLC cells in proliferative assays, but did not inhibit their capacity to proliferate in response to DT despite low levels of CD3 and CD4.

Expression of MHC class II and Tac antigens on IL2-activated human T cell clones that can stimulate in MLR, AMLR, PLT and can present antigen

The expression of interleukin 2 (IL2) receptor and HLA-DR, DQ, and DP antigens on the surface of four diphtheria toxoïd (DT)-specific T lymphocyte clones (TLC) and two TLC specific for an allogeneic EBV-transformed cell line was investigated with the use of monoclonal antibodies (MoAbs) that recognize defined molecules or epitopes. Incubation of a resting TLC with IL2 resulted in a 10- to 30-fold increase in the level of DR, DQ, and Tac antigen expression. On the other hand, incubation of an activated TLC with IL2 decreased for 1 to 6 hr the level of expression of these three antigens. Anti-FA MoAbs did not react with any of the TLC tested suggesting that the expression of DR, DQ, and DP antigens is dissociated on activated TLC. Surface-marker analysis with anti-DR MoAbs indicated that DR epitopes were differently expressed at some activation stages of the TLC. Functional studies showed that activated TLC can stimulate in MLR, AMLR, and PLT. These proliferative responses were inhibited by preincubating the TLC with anti-DR MoAbs suggesting that the stimulatory determinants were predominantly DR molecules. In addition, some TLC can act as antigen presenting cells in DT-specific proliferative responses. These results indicate that MHC class II molecules on activated T lymphocytes may be relevant for the control of specific immunologic responses in vivo.

Differences in carbohydrate specificities and complement-activating capacity of guinea pig and human antibodies to neuraminidase-treated autologous erythrocytes

Guinea pig erythrocytes desialated by treatment with neuraminidase from Vibrio cholerae were lyzed in autologous serum through a natural-antibody-dependent activation of the classical complement pathway. Lysis was inhibited when a mannose, glucose, galactose or N-acetyl-glucosamine was added to the incubation mixture. Methyl-alpha- or -beta-D-galactopyranosides were poorly effective and N-acetyl-D-galactosamine was not effective at all. Inhibition of lysis by the carbohydrates was due neither to an anti-complementary effect nor to a modification of the osmotic pressure since: (a) they did not alter the total complement haemolytic activity of guinea pig serum, and (b) they did not inhibit lysis of desialated guinea pig erythrocytes in human serum through activation of the alternative complement pathway. The presence of mannose, glucose, galactose or N-acetyl-glucosamine in the incubation mixture resulted in an impaired fixation of natural auto-antibodies on antigenic sites, namely the T-antigen (Thomsen-Friedenreich), which were unmasked following membrane sialic acid removal. When tested under the same conditions, only small percentage of the normal human population showed the phenomenon of lysis of desialated erythrocytes in autologous serum. Lysis was not due to a particular susceptibility of erythrocytes from these individuals to complement-mediated lysis but to the presence in their serum of complement-activating anti-T antibodies. As expected, the activity of human anti-T antibodies was inhibited by galactose and N-acetyl-galactosamine, which are the immunodominant sugars of the human T-antigen. Mannose and glucose had no effect, and methyl- alpha- or - beta-D-galactopyranosides were almost as effective as galactose. The heterogeneity of the human population with regard to the complement-activating capacity of anti-T antibodies could be of significance for the individual response of the host to an infection by a neuraminidase-producing microorganism. That the immunodominant sugars of the T-antigen were different between humans and guinea pigs was further assessed by absorption experiments. We have demonstrated that guinea pig anti-T antibodies were not removed during contact with desialated human red cells which do not have the mannose specificity, whereas human antibodies were almost entirely retained on desialated guinea pig red cells which, beside mannose, express galactose. These results also suggest that guinea pig antibodies are mostly directed towards mannose and glucose.

Critical analysis of T cell subset and function evaluation in patients with persistent generalized lymphadenopathy in groups at risk for AIDS

In order to determine whether there exists a distinct immunological profile that discriminates between healthy homosexual men and those expressing persistent generalized hyperplastic lympadenopathy GHL and which of the observed abnormalities in GHL would be most indicative of patients who would eventually develop AIDS, we evaluated T lymphocyte subset and in vitro proliferative responses. The respective profiles of 44 symptom free homosexual men (HC), 42 patients with GHL and 30 cases of AIDS were compared to that of blood bank volunteers (BBV) and to each other, using stepwise discrimination analysis. HC, GHL and AIDS patients demonstrated upon their first investigation varying degrees of the same type of abnormal immunological characteristics. The percentage of OKT4+ cells was the most discriminant variable between BBV and HC, GHL or AIDS. GHL was distinguished from HC primarily by a higher percentage of OKT8+ cells and from AIDS by higher T lymphocyte counts, while the OKT4+ cell count discriminated between AIDS and HC. However, none of these major discriminant variables could classify correctly more than 71% within the HC and the two patient groups. Thus, there exists a continuity between GHL and AIDS in the range of observed immunological abnormalities without clearcut boundaries. This, together with the existence of abnormal background values in HC will not permit a single investigation of T lymphocyte immune parameters to provide substantial diagnostic and prognostic evidence.

Impaired IgG synthesis in patients with the nephrotic syndrome

Immunoglobulin synthesis by pokeweed mitogen-stimulated lymphocytes from 62 nephrotic patients and 18 healthy controls was studied. Defective IgG production was observed in patients with the nephrotic syndrome related to minimal change disease, mebranous glomerulonephritis and membranoproliferative glomerulonephritis. The mean values of in vitro IgG synthesis were 20%, 61% and 32%, respectively, of that obtained in the control group. At the same time, serum IgG levels were significantly decreased in each group of patients. In minimal change disease, reduced IgG production and serum levels were fully reversible after recovery (off steroid therapy). The data indicate that a cellular defect of antibody production is a common and eventually transitory phenomenon associated with the acquired hypogammaglobulinemia found in patients with a variety of glomerulopathies.