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Biomedical subjects

A N Phillips

Publications and source records attributed to A N Phillips.

At least 127 records · Page 7Linked to original sources
PubMed1996

Comparison of immunodeficiency and AIDS defining conditions in HIV negative and HIV positive men with haemophilia A.

OBJECTIVE: To investigate the hypothesis that high usage of clotting factor concentrate, rather than HIV infection, is the cause of immunodeficiency and AIDS in men with haemophilia. DESIGN: A comparison of AIDS defining conditions and CD4 counts in HIV positive and HIV negative patients with haemophilia matched for usage of clotting factor concentrate. SETTING: A comprehensive care haemophilia centre. SUBJECTS: 17 HIV positive and 17 HIV negative male patients with haemophilia A (age range 12-60 at beginning of study period) who had received similar amounts of clotting factor concentrate yearly over the years 1980-90. MAIN OUTCOME MEASURES: Clinical events listed as AIDS defining in the Centers for Disease Control AIDS definition; CD4 lymphocyte counts; death. RESULTS: Of 108 HIV positive male patients with haemophilia A, only 17 could be matched to an HIV negative patient. This was due to the much higher average usage of factor VIII in the HIV positive group. Between 1980 and 1990, 16 clinical events occurred in nine of the 17 HIV positive patients. No event occurred in the 17 HIV negative patients. In each pair the mean CD4 count during follow up was, on average, 0.5 x 10(9)/l lower in the HIV positive patient. CONCLUSION: These data reject the hypothesis that high usage of clotting factor concentrate, rather than HIV infection, is the cause of immunodeficiency and AIDS in men with haemophilia.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Reduction of HIV concentration during acute infection: independence from a specific immune response.

After infection with the human immunodeficiency virus (HIV), the concentration of the virus in the person's plasma increases. The subsequent decrease in concentration a few weeks later was though to result from an HIV-specific immune response. This purported causal relation is investigated with a model of the dynamics of early HIV infection that incorporates no increase in the rate of removal of free virions or virus-infected cells. A pattern of changes in virus concentration similar to that observed in patients is predicted by the model. Thus, the reduction in virus concentration during acute infection may not reflect the ability of the HIV-specific immune response to control virus replication.

Acute Disease↗
PubMed1996

Factors associated with the CD4+ lymphocyte count at diagnosis of acquired immunodeficiency syndrome. The AIDS IN EUROPE Study Group.

To assess which factors are associated with the CD4+ lymphocyte count at the time of AIDS diagnosis we studied 3046 patients in the AIDS IN EUROPE study who were diagnosed with AIDS in 1 of 17 European countries between 1979 and 1989 and for whom the CD4 count at AIDS diagnosis was known. Data were extracted retrospectively from patient case notes, using a standardized form. There was a wide range of average CD4+ lymphocyte counts at AID diagnosis, according to which diseases were present at diagnosis. The highest geometric mean CD4+ lymphocyte counts at AIDS diagnosis were associated with the diagnosis of extrapulmonary tuberculosis, Kaposi's sarcoma, and non-Hodgkin's lymphoma while the lowest counts were found when histoplasmosis and cytomegalovirus (CMV) retinitis were present. There were no appreciable differences between CD4+ lymphocyte counts at AIDS in patients according to the three major transmission route categories (sex, age, or region of diagnosis) but there was a marked trend (p < 0.005) toward lower CD4+ lymphocyte counts at AIDS diagnosis in more recent years. These associations remained largely unchanged after adjustment for other factors.

AIDS-Related Opportunistic Infections↗
PubMed1996

Increased numbers of primed activated CD8+CD38+CD45RO+ T cells predict the decline of CD4+ T cells in HIV-1-infected patients.

OBJECTIVE: To look for surrogate markers in HIV-1 infection that can predict the decline of CD4+ T cells. METHODS: Multiparameter flow cytometric analyses of CD8+ lymphocytes were performed. These cells were investigated for their expression of the activation marker CD38+ within the naive (CD45RA+) and primed (CD45RO+) subsets. Serial CD4 counts were plotted for each patient and the straight line that best fitted was obtained using least squares regression. Differences in rate of decline were tested using analysis of variance, after each patient was weighted by the reciprocal of the variance. RESULTS: Baseline levels of percentages of CD8+CD38+ T lymphocytes predict the CD4 decline in HIV-1-infected patients. Within the CD8+ subset, the primed CD8+CD38+CD45RO+ population was responsible for this prediction. Conversely, the naive CD8+CD38+CD45RA+ population was not predictive. Patients who initially showed a percentage of CD8+CD38+ T lymphocytes above the median (> 25%) had a more marked decline in CD4+ T cells when compared to individuals with percentages of CD8+CD38+ T lymphocytes below the median value (79.3 and 21.2 x 10(6)/l mean CD4 cell decline per year, respectively). Similarly, percentages of CD8+CD38+CD45RO+ T cells above the median value (> 7%) were also associated with a more rapid decline (69.4 and 14.2 x 10(6)/l mean CD4+ cell decline per year). These results were statistically significant after adjustment for the baseline CD4 count and beta 2-microglobulin levels. CONCLUSIONS: Percentages of activated CD8+ cells expressing CD38+ can predict the rate of decline (slope) of the CD4+ T cells. This resides in the CD45RO+ primed population. An early prediction of the CD4+ slope will allow the clinician to target treatment to those patients that are most likely to benefit.

ADP-ribosyl Cyclase↗
PubMed1996

HIV-1 RNA levels and the development of clinical disease. North American Lamivudine HIV Working Group.

OBJECTIVE: To assess the prognostic value of HIV RNA levels for predicting clinical disease independently of the CD4 lymphocyte count in patients on antiretroviral therapy. DESIGN: Cohort of HIV-infected patients from two trials of lamivudine therapy. PATIENTS: For 620 patients randomized in the North American NUCA3001 and NUCA3002 trials of lamivudine, HIV RNA levels were measured (median, seven measures per patient) and CD4 counts were assessed at a central laboratory (median, 13 counts per patient). Patients were in the 1993 Centers for Disease Control and Prevention (CDC) stages A (n = 439), B (n = 135) or C (n = 46) at baseline. OUTCOME MEASURES: For patients who were in CDC stage A at baseline we considered the ability of HIV RNA levels and CD4 counts to predict the development of CDC stage B or C disease. A Cox proportional hazards model was used. In a second analysis, patients who were AIDS-free at baseline were considered, and the endpoint was AIDS (CDC stage C). RESULTS: Patients' initial CD4 counts ranged (5-95% centiles) from 104 to 529 x 10(6)/l (median, 274 x 10(6)/l) and HIV RNA levels from 1900 to 339680 copies/ml (median, 44240 copies/ml). For the first analysis, with CDC stage B or C disease as endpoint, both the most recent HIV RNA level and CD4 count predicted the development of clinical disease [relative hazard (RH) for HIV RNA, 1.96 per 10-fold difference in HIV RNA; 95% confidence interval (CI), 1.41-2.73; P = 0.0001; and RH for CD4 count, 1.82 per twofold difference in CD4 count; 95% CI, 1.27-2.56; P = 0.0009]. When both HIV RNA and CD4 count were included in a multiple regression model, both markers provided information additional to that given by the other (RH for HIV RNA, 1.75; 95% CI, 1.23-2.50; P = 0.002; and RH for CD4 count, 1.40; 95% CI, 0.95-2.07; P = 0.09). In the second analysis, with AIDS as endpoint, both HIV RNA level (P = 0.02) and CD4 count (P = 0.004) were independently associated with clinical progression. These results were essentially unchanged after adjustment for treatment arm (zidovudine/lamivudine versus control arms). CONCLUSION: The HIV RNA level shows ability to predict the development of clinical disease and may thus be of importance in addition to the CD4 count in patient monitoring.

Adult↗
PubMed1996

Spectrum of disease in Africans with AIDS in London.

OBJECTIVE: To compare the spectrum of disease, severity of immune deficiency and chemoprophylaxis prescribed in HIV-infected African and non-African patients in London. DESIGN: Retrospective review of case notes of all HIV-infected Africans and a comparison group of non-Africans attending 11 specialist HIV/AIDS Units in London. MAIN OUTCOME MEASURES: Comparison of demographic information, first and subsequent AIDS-defining conditions, levels of immune deficiency, and chemoprophylactic practices between the African and non-African groups. RESULTS: A total of 1056 Africans (313 developing AIDS) and 992 non-Africans (314 developing AIDS) were studied. Africans presented later than non-Africans (median CD4+ lymphocyte counts at diagnosis 238 and 371 x 10(6)/l, respectively). Tuberculosis accounted for 27% of initial episodes of AIDS in Africans and 5% in non-Africans; Pneumocystis carinii pneumonia (PCP) was the initial AIDS-defining condition in 34% of non-Africans and 17% of Africans. The incidence of tuberculosis in Africans with another AIDS-indicator disease was 16 per 100 person-years. PCP prophylaxis was prescribed for 40% Africans and 32% non-Africans; only 8% of Africans received tuberculosis preventive therapy. CONCLUSIONS: HIV-infected African patients presented at lower levels of CD4+ lymphocyte count, at a more advanced clinical stage, and with different AIDS-indicator diseases as compared with non-Africans. Prophylaxis against tuberculosis should be considered for all HIV-infected African patients in industrialized countries. The high incidence of diseases that are indicative of advanced immunodeficiency (e.g., cytomegalovirus disease) in African patients contrasts with data from Africa, suggesting better survival chances in the UK.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Reference ranges and sources of variability of CD4 counts in HIV-seronegative women and men.

BACKGROUND: CD4 lymphocyte counts are used to monitor immune status in HIV disease. An understanding of the variability of CD4 counts which occurs in the absence of HIV infection is essential to their interpretation. The sources and degree of such variability have not been extensively studied. OBJECTIVES: To establish reference ranges for CD4 counts in HIV-seronegative women and heterosexual men attending a genitourinary medicine (GUM) clinic, and to identify possible differences according to gender and cigarette smoking and, in women, any effect of the menstrual cycle, oral contraceptive use and cigarette smoking. DESIGN: Female and heterosexual male patients attending a GUM clinic and requesting an HIV-antibody test were recruited prospectively. Results from an earlier study of CD4 counts in homosexual men were available for comparison. METHODS: Lymphocyte subpopulation analysis on whole blood by flow cytometry. RESULTS: The absolute CD4 count and percentage of CD4 cells (CD4%) were significantly higher in women (n = 195) than heterosexual men (n = 91) [difference between the means 111 x 106/1 (95% CI 41, 180) and 3.1% (1.30, 4.88)]. The absolute CD4 count and CD4% were also significantly higher in smokers (n = 143) than non-smokers (n = 140) [difference 143 (79, 207) and 2.1% (0.43, 3.81)]. Reference ranges for absolute CD4 counts (geometric mean +/- 2SD) were calculated on log transformed data as follows; female smokers 490-1610, female non-smokers 430-1350, heterosexual male smokers 380-1600, heterosexual male non-smokers 330-1280. Among other variables examined, combined oral contraceptive pill use was associated with a trend towards a lower absolute CD4 count. Changes were seen in CD4% with the menstrual cycle. CD4 counts and CD4% did not differ significantly between heterosexual men and homosexual men (n = 45). CONCLUSION: There is a significant gender and smoking effect on CD4 counts. The effects of oral contraceptive use and the menstrual cycle warrant further investigation.

Adolescent↗
PubMed1996

Anti-herpesvirus treatment and risk of Kaposi's sarcoma in HIV infection. Royal Free/Chelsea and Westminster Hospitals Collaborative Group.

OBJECTIVE: With the recent identification of a new herpesvirus in patients with Kaposi's sarcoma (human herpesvirus-8 or Kaposi's sarcoma-associated herpesvirus), there have been several reports on the use of anti-herpesvirus therapy (foscarnet, ganciclovir and aciclovir) and risk of developing Kaposi's sarcoma. We therefore investigated the association between use of anti-herpesvirus drugs and Kaposi's sarcoma in a large unselected group of patients with AIDS. PATIENTS AND METHODS: We studied a group of HIV-positive patients at the Chelsea and Westminster Hospital, for whom details on all AIDS-defining diagnoses made during follow-up, treatment and regular CD4 counts were available. Cox proportional hazards models with time-dependant covariates were used to assess the association between treatment with aciclovir, foscarnet and ganciclovir and risk of Kaposi's sarcoma. RESULTS: A total of 3688 patients have been followed up for a median period of 4.2 years, during which time 598 patients (16.2%) developed Kaposi's sarcoma. After adjustments for sex, exposure category, age, treatment with antiretrovirals or Pneumocystis carinii pneumonia prophylaxis, the development of AIDS-defining conditions (including separate adjustment for the development of cytomegalovirus and herpes simplex virus) and CD4 count, there was a decreased risk of developing Kaposi's sarcoma with foscarnet [relative hazard (RH), 0.38; 95% confidence interval (CI), 0.15-0.95; P = 0.038] and with ganciclovir (RH, 0.39; 95% CI, 0.19-0.84; P = 0.015), but not with aciclovir (RH, 1.10; 95% CI, 0.88-1.38; P = 0.40). CONCLUSIONS: These results suggest that both foscarnet and ganciclovir may have some activity in preventing the occurrence of Kaposi's sarcoma, but that aciclovir has no benefit. Further studies of the effect of these drugs on the risk of Kaposi's sarcoma is warranted.

Acyclovir↗
PubMed1996

Ethnic differences in women with HIV infection in Britain and Ireland. The study group for the mrc collaborative study of HIV infection in women.

OBJECTIVE: To examine ethnic differences in the socio-epidemiological and clinical characteristics of a cohort of women with HIV infection in Britain and Ireland. DESIGN AND METHODS: Analysis of baseline data (ethnic group, sexual history, likely route of HIV infection, reasons for HIV testing and first AIDS-defining disease) from 400 women with HIV infection recruited into a cohort study from 15 genitourinary medicine/HIV clinics in Britain and Ireland. RESULTS: Sixty-five per cent of women were white and 29% black African. Their median number of lifetime sexual partners was seven and three, respectively (P < 0.001). Ninety-three per cent of black African and 43% of white women were probably infected through sexual intercourse. Injecting drug use was the most likely route of infection in 55% of white women, but none of the black African women. Perceived risk (33%) or investigation of symptoms (26%) were the most common reasons for HIV testing. Seven per cent of white women and 16% of black African women (P < 0.001) had AIDS when HIV infection was diagnosed. The distribution of first AIDS-defining diagnoses differed (P = 0.001) by ethnic group. For white women, the most common disease was Pneumocystis carinii pneumonia; for black African women it was pulmonary tuberculosis. CONCLUSION: There are important differences between black African and white women in sexual history and route of transmission, disease stage at diagnosis and pattern of AIDS-defining diseases.

AIDS Serodiagnosis↗