Costimulation of CD4+ and CD8+ T cells through CD26: the ADA-binding epitope is not essential for complete signaling.

It was previously shown that CD26 (DPP IV, EC 3.4.14.5) is a binding site for adenosine deaminase (ADA, EC 3.5.4.4) on T cells and that costimulation by some anti-CD26 monoclonal antibodies (mAbs) and anti-CD3 induces CD4+ T cell proliferation. The CD26 epitopes involved in costimulation, the precise sequence of the events preceding proliferation, and the response of CD8+ compared with CD4+ T cells to CD26 were not extensively studied. We therefore compared the effects of the novel TA5.9 anti-CD26 mAb, recognizing an ADA-binding epitope, and the clearly distinct anti-Ta1 reference anti-CD26 mAb for their costimulatory properties in various T cell subsets. Both purified CD4+ and CD8+ T cells proliferated upon costimulation with anti-CD3 and either anti-CD26 mAb, but anti-TA5.9 mAb induced a more potent response than anti-Ta1. Either anti-CD26 mAb, together with anti-CD3, caused a similar sequential up-regulation of CD69, CD25 (IL-2R alpha), and CD71 (transferrin receptor) expression on CD4+ and CD8+ T cells. The activation markers appeared faster on the CD45R0+ than on the CD45R0- subsets. After costimulation, CD4+ T cell cultures contained significant amounts of the Th1 cytokines IL-2, interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha (TNF-alpha). In CD8+ T cell cultures relatively more IFN-gamma and TNF-alpha but almost no IL-2 was measured after triggering of CD3 and CD26. Our data demonstrate that the recognition of the ADA-binding epitope is not a prerequisite for the costimulatory capacity of anti-CD26 mAbs. Both CD4+ and CD8+ T cells and their CD45R0- and CD45R0+ subsets are sensitive to various aspects of activation via CD26, but the magnitude and/or kinetics differ according to the anti-CD26 used and the T cell subset studied.

Expression of activation antigens, HLA-DR and CD38, on CD8 lymphocytes during HIV-1 infection.

OBJECTIVE: To study the expression of the activation markers human leukocyte antigen (HLA)-DR and CD38 antigen on CD8+ T-lymphocytes in HIV-infected subjects and HIV-negative controls. DESIGN: Two- and three-colour flow-cytometric analysis. METHODS: Fresh peripheral venous blood was obtained from 16 HIV-infected subjects, representing four different stages of HIV disease, and from six HIV-negative controls. Three-colour lymphocyte immunophenotyping was performed using peridinyl chlorophyll-A protein (PerCP)-conjugated anti-CD8 monoclonal antibody (MAb) in combination with anti-HLA-DR (phycoerythrin) and anti-CD38 (fluorescein isothiocyanate) MAb. RESULTS: The relative percentage of the lymphocyte populations thus defined differed between HIV-negative and HIV-positive subjects and between HIV-infected subjects at different clinical stages of disease. Simultaneous expression of HLA-DR and CD38 within the CD8 T-lymphocyte compartment increased from 8% in controls to 49% in asymptomatic HIV-infected subjects (P less than 0.005). Symptomatic patients differed from asymptomatic seropositives by a further increase in the HLA-DR+ CD38+ CD8 subset. In AIDS patients, the HLA-DR+ CD38- CD8 subset decreased (P less than 0.05) and the HLA-DR- CD38+ CD8 subset increased (P less than 0.05), compared with the other HIV disease stage patients. CONCLUSION: There is a stage-associated pattern of HLA-DR and CD38 expression on CD8 T-lymphocytes during HIV infection; specific phenotypic patterns may have functional correlates in the host response to the virus.

Generalized papular pruritic eruption in African patients with human immunodeficiency virus infection.

Of 284 patients hospitalized with HIV infection, 52 (18%) presented with a generalized pruritic papular eruption. No significant association between this eruption and other HIV manifestations or any opportunistic infection was found. Fifty-three of 61 (87%) consecutive African patients referred for a generalized papular pruritic eruption of unknown etiology of at least 1 month's duration were HIV seropositive, including 15 (65%) of 23 in good general condition. Thirty-seven (95%) of 38 patients with this eruption and severe weight loss (greater than 10% of normal body weight) were seropositive. The initial skin lesions were small, firm, intensely pruritic papules which released a small drop of clear fluid when scratched. Scratched papules became later hyperpigmented macules. Lesions were symmetrically distributed over the body and were most frequently found on the extensor surfaces of the arm, the dorsal surface of the hands, the inferior part of the legs, the ankles and the dorsum of the feet. Histologic examination showed a non-specific inflammatory reaction. Thirty-three (51%) patients reported that the skin eruption was their initial disease manifestation. In African patients, the presence of an unexplained generalized pruritic papular eruption is highly indicative of HIV infection.

Immunological parameters during treatment with ditiocarb (Imuthiol).

OBJECTIVES: To examine the effect of ditiocarb (DTC) treatment on immunological parameters of HIV infection. Immunophenotyping included CD4+ T-cell counting and the analysis of activation markers on CD8+ T cells. Anti-CD3-induced proliferation and anti-CD3-mediated cytotoxicity were monitored as indexes of T-cell function. In addition to the clinical evolution, HIV antigen and anti-p24 levels were monitored during treatment. DESIGN: In this double-blind, placebo-controlled study, 50 HIV-seropositive patients belonging to all clinical disease stages were randomized to treatment with DTC or placebo and followed for 4 months. METHODS: Immunophenotyping on whole blood was performed by flow cytometry, using combinations of anti-CD8 with anti-CD4, anti-HLA-DR, anti-CD38, anti-CD45RO and anti-CD57. Patient lymphocytes were freshly assayed for cytolytic capacity against OKT3-coated targets. T-cell proliferation was measured after 3 days of OKT3-stimulation. RESULTS: No effect was observed on CD4 and CD8+ T-cell counts or on CD8+ T-cell activation markers, except for a selective increase in HLA-DR expressing CD8 cells in the DTC-treated group. Decline in anti-CD3-induced T-cell proliferation and rise in anti-CD3-mediated T-cell cytotoxicity were observed in the DTC and placebo groups. No effect on HIV antigen and anti-p24 antibody titres was observed. The incidence of clinical complications was similar in each group. CONCLUSION: No beneficial immunomodulatory effect of DTC was demonstrated.

Immunological comparison of HIV-1-, HIV-2- and dually-reactive women delivering in Abidjan, Côte d'Ivoire.

OBJECTIVES: To compare the basic immunological changes induced by HIV-1 and HIV-2 infection and to assess the immune status of subjects serologically reactive to both HIV-1 and HIV-2 (dually-reactive). DESIGN: Immune parameters were studied cross-sectionally in women delivering in Abidjan, Côte d'Ivoire, West Africa, where HIV-1 and HIV-2 are endemic. In this area, a significant number of sera from infected individuals are reactive to both HIV-1 and HIV-2. SUBJECTS AND METHODS: Two hundred and twenty-eight women delivering in a major maternity clinic were screened for HIV-1 and HIV-2 using an enzyme-linked immunosorbent assay. Seropositivity was confirmed by Western blot. The immune parameters studied were CD4+ and CD8+ lymphocyte subsets, immunoglobulin (Ig) serum levels, neopterin and beta 2-microglobulin (beta 2M) serum levels. RESULTS: Similar but less pronounced immune changes were present in HIV-2-reactive subjects compared with HIV-1- and dually-reactive subjects. The observed differences between the HIV-seropositive groups could not be explained by differences in age or disease stage but paralleled differences in the frequency of persistent generalized lymphadenopathy (PGL). The intermediate immune profile of HIV-2-reactives (between seronegatives and HIV-1- and dually-reactives) was most clearly reflected by the number of CD8+ lymphocytes, the CD4:CD8 ratio and the IgG serum level. Median neopterin and beta 2M levels, though significantly increased in all HIV-seropositive groups, did not differ significantly between HIV-2-, HIV-1- and dually-reactives. CONCLUSIONS: HIV-2 infection is associated with typical HIV-related immunological changes. Immunologically, dually-reactives resemble HIV-1-reactives more closely than HIV-2-reactive subjects.

A useful method for determining class-specific rheumatoid factors with computerized analyses of data.

A simple and sensitive enzyme-linked immunosorbent assay (ELISA) was developed to determine rheumatoid factors (RFs) of IgG, IgA and IgM class. Standardisation was performed with a standard reference serum for IgM-RF, calibrated according to the WHO preparation, and with the serum of a patient containing high levels of IgA- and IgG-RF. The sigmoidal shaped calibration curve was fitted with a computerized four parameter logistic model with simplified mathematical computations. This method provided to be more accurate for measuring RF levels, as judged by the smaller residuals, than logit or log-linear transformations. The considerable reduction in processing time, which is obtained by the computerized analysis of data, makes this method of class-specific RF determination suitable for routine analysis.

Deficient T-cell responses in non-responders to hepatitis B vaccination: absence of TH1 cytokine production.

The inability to mount a protective level (> or = 10 IU/l) of hepatitis B surface antigen (HBsAg)-specific antibodies after vaccination is presumably the consequence of a defect in the cellular immune regulation. We compared the in vitro immune responses of peripheral blood mononuclear cells (PBMC) from high, intermediate and non-responders, after stimulation with recombinant HBsAg. The absence of a proliferative response in non-responders was not reversed by removal of CD8+ T cells, indicating that HBsAg-specific CD8+ T-cell-induced suppression was not the underlying cause of non-responsiveness. Non-responders did not produce cytokines after HBsAg stimulation. High responders displayed a typical Th1-like profile since their PBMC produced interleukin-2 (IL-2) and gamma-interferon (IFN gamma) and no detectable IL-4 or IL-5 upon stimulation with HBsAg.

Renal disease in chronic experimental Trypanosoma gambiense infections.

Two recently isolated stocks of Trypanosoma brucei gambiense of human origin gave rise to a moderate to severe proliferative or membranoproliferative glomerulonephritis in 40 or 44 NMRI and C57BL/6J mice infected for 7-22 weeks. Extensive granular deposits of C3, IgG1 and IgG3 were found in the mesangium, together with smaller quantities of IgG2a, IgG2b, and IgM. No trypanosomal antigen could be detected in the deposits though specific anti-trypanosoma antibodies were found in kidney eluates. By electron microscopy, a conspicuous proliferation of mesangial and endothelial cells was observed and electron-dense deposits were seen in a mesangial and subepithelial localization. With one of these trypanosome stocks, four of seven Wistar rats infected for 9-15 weeks developed morphologically similar glomerular lesions. Four other trypanosome stocks did not evoke renal alterations in 17 other rats infected for 13-56 weeks. Experimental infection in mice or rats appears to be a suitable model for the study of renal disease in chronic African sleeping sickness.

Oesophagostomiasis, a common infection of man in northern Togo and Ghana.

Infection with Oesophagostomum sp. is normally considered a rare zoonosis and up to this time its diagnosis has been based on the demonstration of larvae and young adult worms in the typical nodules formed in the intestinal wall. Only in Dapaong, in North Togo, and Bawku, North Ghana, have larger series of clinical cases been described. In the rural areas around these towns, a survey was made in which stool samples were collected and cultured. Third-stage larvae of Oesophagostomum sp. could be found after 5-7 days of incubation at room temperature, and the prevalence of infection with this parasite was often high but varied from one village to another. It was over 30% in seven villages out of the 15 villages surveyed. Anthelmintic treatment resulted in the evacuation of adult males and females of O. bifurcum. It is concluded that O. bifurcum is a locally common parasite of humans, not requiring an animal reservoir for completion of its lifecycle.

HIV antigen detection in circulating immune complexes.

Various methods were evaluated for their effectiveness in releasing HIV antigen (Ag) from artificial immune complexes (IC) and from IC present in serum from HIV antibody (Ab) positive subjects. The most effective methods for recovering HIV Ag from IC were those which included a denaturation step to prevent reassociation of Ag with Ab. IC precipitation in 2.5% polyethylene glycol followed by acid treatment with 1 M glycine.HCl (pH 2) for 10 min at 70 degrees C in the presence of 0.05% SDS gave very satisfactory results. With this method, IC were detected in sera from HIV antibody positive Caucasian subjects at all stages of infection. After HIV IC dissociation, HIV Ag was detected in a significant number (8/17 or 47%) of asymptomatic subjects. IC were most prevalent during the late stages of infection. A substantial increase in HIV Ag positivity was also observed in 20 Senegalese HIV Ab positive sera. After HIV IC dissociation HIV antigen detection increased from 2/20 to 12/20. The relevance of IC detection is discussed.

Parotid swelling during human immunodeficiency virus infection.

In Europe and in the United States, bilateral parotid gland swelling has been observed as a sign of human immunodeficiency virus (HIV) infection in children, but it has not been associated with HIV infection in adults. We observed a chronic parotid gland swelling in nine HIV-seropositive patients during a nine-month period in Kinshasa, Zaire. Parotid gland enlargement was bilateral in seven patients (78%), slightly painful in seven patients (78%), and painless in two patients (22%). No evidence of inflammation was observed around Stensen's duct. One of the two patients in whom a parotid gland biopsy was performed had a malignant lymphoma of the large-cell, histiocytic type. In the other patient, the parotid gland showed normal morphology with minor inflammation. Among 284 adults and 40 children with symptomatic HIV infection, chronic parotid gland enlargement was observed in none of the patients. However, two (0.7%) of the adults presented with an acute pyogenic parotitis. Further studies are needed to determine whether parotid gland enlargement is associated with HIV infection.

Spontaneous glomerular basement membrane changes in the golden Syrian hamster (Mesocricetus auratus): a light and electron microscope study.

Changes in apparently healthy hamsters, consistent with proteinuria, are reported, but no IgG deposits or amyloid in the glomeruli were detected. Further investigation is required into the significance and the aetiology of these, as yet, obscure alterations.

[Epidemiology of Kaposi's sarcoma in Africa]. / Epidémiologie du sarcome de Kaposi en Afrique.

The epidemiology of Kaposi's sarcoma in Africa south of the Sahara is reviewed. The disease is characterized by its high incidence in natives only and by the presence of the lymphadenopathic form of children with fast evolution, but is otherwise not very different from the classical form. Incidence increases with age. The mean younger age of patients is a consequence of the demographic structure. The disease prevails always in males even, though to a lesser extent, in children. Maximal incidence is observed in the center of the continent and decreases at distance from the equator. No defined risk factor has been identified, geographical, tribal or socio-economical. Associations to other malignancies, especially lymphomas, appear uncommon in Africa, but might be underestimated. The three main clinical forms of the disease are probably epidemiologically different and the infantile form could be related to some unidentified immunosuppressive factor. The disease appears ancient in Africa and not directly related to the present A.I.D.S. epidemic, though a recent increase in aggressive Kaposi's sarcoma cases may be associated with it.

[Urinary bilharziasis]. / La bilharziose urinaire.

A short account is given of present views on urinary schistosomiasis or bilharziasis. The incidence of infections is increasing in endemic areas of Africa and the near east, as a consequence of irrigation programs and hydroelectric power development. Urinary schistosomiasis is a disease of children and young adults. The serious consequences, obstructive uropathy due to more or less irreversible ureteral lesions, and cancer of the bladder, less directly related to the infection, appear but later in life. Diagnosis is still based on parasitology and serology but ultrasonography has proven to be an important means to evaluate the extent of lesions of the urinary tract, especially in developing countries. Praziquantel was a major development in the medical treatment and cures easily the infection. Some irreversible consequences have however to be treated surgically. Schistosomiasis is still an important cause of morbidity and mortality in medically backward endemic countries. The control of the disease aims at reducing morbidity and mortality, consequences of the infection, rather than to avoid infection itself. It is based on mass treatment of school age children, together with focal molluscacides at places where people have contacts with water. Vaccination will be available in the near future and will be a welcome addition to other control measures, but will not be able to interrupt transmission on its own. Only economic development will solve in the long term this social African problem.

Further African cases of rhinosporidiosis.

Thirteen African cases of rhinosporidiosis are reported from Burundi, Rwanda, Tanzania, Chad and Zaire. They include the first reported cases from Burundi and from Rwanda and the first African case, outside nose and eye, localized on the urethral orifice in a Zairian male.

The prevalence of intestinal parasites in two suburbs of Kinshasa (Zaire) and their relation to domestic water supplies.

The prevalence of common intestinal nematodes (Ascaris, Trichuris and hookworms) and protozoa (Entamoeba coli, E. histolytica, Giardia, Trichomonas) was compared in two suburbs of Kinshasa, one provided with piped water and the other one with wells. Pit latrines were used in both places. No significant differences were observed for the worms, but the prevalence of the four common protozoa was approximately twice as high in the community without piped water supply. It is concluded that providing piped water has some impact on the transmission of potentially pathogenic intestinal protozoa, but no influence, at least on the short run, on intestinal worms. Infections with Giardia and Trichomonas were significantly associated.

Kaposi's sarcoma in Zaire.

Kaposi's sarcoma (KS) was recognized in 1948 in Zaire, where it has probably always been endemic. In 1957 a relative frequency of KS of 9% of all biopsied cancers was found. There are fluctuations in incidence within the country, with a higher incidence in the east, where it was estimated in 1960 at about 5-10 cases per 100 000 per year in males, with a relative frequency of 14% of all malignant male tumours and a M/F ratio higher than 10/1. More recently KS accounted for roughly 17% in males and 2% in females of all malignant biopsied tumours in north-east Zaire (1969-1983). In 2 years (1982-1983), 26 male and 5 female KS cases were histologically confirmed in an area of eastern Zaire with a population of roughly 300 000 people. It has been suggested, on the basis of this high incidence of KS and of the recent identification of African AIDS cases, that the hypothetical transmissible agent in AIDS might originate from Central Africa. The frequency of KS in African AIDS cases was low (16%) as compared to that in the USA. The M/F ratio of AIDS was 6/4 and that of AIDS-associated KS 1/1. AIDS-associated cases occurred in young adults and were generalized and fulminating. African KS occurs at a younger modal age than in Caucasians, which is the combined result of increasing incidence with age and of the high proportion of young people in the population in Africa but not of a higher risk for younger male adults, as in AIDS.(ABSTRACT TRUNCATED AT 250 WORDS)

A convenient and economical freezing procedure for mononuclear cells.

Cryopreservation techniques have become essential in longitudinal evaluation of lymphocyte function. This study describes a convenient method for freezing of peripheral blood mononuclear cells, using a small cryocontainer. Analysis of cell function, assayed by lymphoproliferation to recall antigens and by cytotoxic capacity of activated lymphocytes, was performed in parallel on fresh and frozen-thawed cells. Although cryopreservation did affect lymphocyte function, our results indicate that this freezing method performed equally well compared to a computer controlled device. We conclude that the cryocontainer has proved to be a suitable and practical tool in clinical studies and is an economical alternative to conventional methods.

Experimental infections of laboratory rodents with recently isolated stocks of Trypanosoma brucei gambiense. 1. Parasitological investigations.

Albino rats and white mice were infected with populations of Trypanosoma brucei gambiense isolated from patients in four different areas in Central Africa. Differences in virulence as shown by the level of parasitaemia, number of relapses, and length of survival time, were observed amongst the stocks according to their geographical origin and secondarily to the degree of adaptation to the rodents. All the stocks are pathogenic for the laboratory rodents, and the presence of extravascular trypanosomes in the brain was confirmed in all infected animals. Spleen, liver, and kidneys were less constantly found to be positive. The morphology of the extravascular parasites was highly variable, ranging from long slender trypomastigotes to spheromastigotes and even amastigotes.

Schistosoma mansoni: impaired clearance of model immune complexes consisting of circulating anodic antigen and monoclonal IgG1 in infected mice.

The clearance of schistosome-specific model immune complexes (IC) consisting of circulating anodic antigen (CAA), a gut-associated excretory-secretory antigen, and radiolabeled monoclonal antibody (IgG1) was investigated in mice with a light and heavy Schistosoma mansoni infection and in noninfected control animals. The size analysis of the in vitro prepared and injected IC, as determined by density gradient centrifugation, revealed a wide peak at 11S. In infected animals the injected IC were cleared at a significantly lower rate than in control mice. This was attributed to a decreased uptake of IC by the liver in infected mice. In heavily infected mice, 30 min after injection of 11S IC, 8S, 11S, and greater than 11S IC were present in the serum, whereas only small 8S IC were detected in the serum of lightly infected animals and noninfected controls. Immune complexes were also present in the serum of heavily infected mice 30 min after injection of antibody and were detectable as 11S and greater than 11S IC. The importance of this study is twofold. First, these results show that schistosome-specific monoclonal antibodies can be used in the production of model immune complexes applicable in clearance studies. Second, our findings might be of importance when the possible pathogenicity of circulating IC in schistosomiasis is considered.