5. Antecedent behavioural, clinical with AIDS and HIV ... - Europe PMC

I Original Research

The Vancouver Lymphadenopathy- AIDS Study: 5. Antecedent behavioural, clinical and laboratory findings in patients with AIDS and HIV-seropositive controls William J. Boyko, MD, FRCPC Martin T. Schechter, MD, MSc, PhD Kevin J.P. Craib, BA, MMath Peter Constance, MB, ChB Rod Nitz, MD Sean Fay, MD Alastair McLeod, MD, FRCPC Michael O'Shaughnessy, PhD In a group of homosexual men in Vancouver studied prospectively since November 1982, 26 cases of acquired immune deficiency syndrome (AIDS) have arisen. To identify behavioural, clinical and laboratory findings that might predict the development of AIDS in people with antibody to human immunodeficiency virus (HIV), we compared data for 25 patients with AIDS with corresponding data for 80 controls serologically positive for HIV selected from the cohort. The clinical and laboratory data for the patients with AIDS preceded the diagnosis of the syndrome by a mean of 17.5 months. The controls had been both seropositive and AIDSfree for a mean of 16.7 months after acquisition of their data. We detected significant differences between the patients with AIDS and the controls in IgG and IgA levels, absolute number of helper T cells and ratio of helper to suppressor T cells but not in lifetime number of male sexual From St. Paul's Hospital and the University of British Columbia, Vancouver, and the Division of Viral Studies, Laboratory Centre for Disease Control, Department of National Health and Welfare, Ottawa

Fifth of a series by the Vancouver Lymphadenopathy-AIDS Study Group. Parts 1, 2, 3 and 4 appeared in the June 1, June 15, July 1 and Aug. 15, 1985, issues of CMAJ respectively.

Reprint requests to: Kevin J.P. Craib, Project manager, Vancouver Lymphadenopathy-AIDS Study, St. Paul's Hospital, 1081 Burrard St., Vancouver, BC V6Z 1 Y6

partners, frequency of receptive anal intercourse or receptive fisting, illicit drug use or history of infectious disease. We also detected an increased risk of AIDS among those who had an elevated number of sexual contacts in AIDS-endemic areas in the 5 years before enrolment. A history of increased early sexual contact in AIDSendemic areas is likely to be associated with early infection and with an increased risk of AIDS among men with HIV infection of unknown duration. Thus, although our analysis had limited statistical power, we conclude that most lifestyle variables appear to act as exposure factors in HIV infection but not as cofactors in the development of AIDS.

Depuis novembre 1982, l'observation prospective d'homosexuels masculins a Vancouver a depiste 26 cas de syndrome immunoddficitaire acquis (SIDA) dont 25 sont mis en comparaison avec 80 temoins seropositifs pour le virus immunodeficitaire humain (VIH) choisis dans la meme cohorte, afin de faire ressortir les facteurs comportementaux, cliniques et biologiques susceptibles de laisser prevoir la survenue du SIDA chez les sujets seropositifs. Pour les malades atteints de SIDA, le bilan clinique et biologique a precdde de 17,5 mois en moyenne le diagnostic. Les temoins ont montrd seropositivite et absence de SIDA pendant 16,7 mois en moyenne apres le bilan clinique et biologique. Dans celui-ci, les CMAJ, VOL. 135, OCTOBER 15, 1986

881

diffErences significatives entre sujets et temoins sont dans le dosage dIgG et d'IgA, le nombre absolu des lymphocytes T adjuvants et le rapport lymphocytes T adjuvants/cytotoxiques. I1 n'y a pas de diffErence significative dans le nombre de partenaires sexuels masculins pour toute la vie, la frequence du colt anal passif et de l'intromission passive de la main, les toxicomanies et les antecedents de maladies infectieuses. Mais le risque de SIDA est plus eleve chez les sujets declarant des contacts sexuels frequents en regions ou le SIDA est endemique dans les 5 annees precedant la presente enquete; la notion de tels contacts precoces va de pair avec l'infection precoce et avec le risque eleve de SIDA chez les hommes dont on ne connalt pas la duree de la seropositivite. On peut dire que la plupart des facteurs de comportement jouent un role dans l'infection par le VIH mais n'affectent pas la survenue du SIDA chez les sujets dEjk sEropositifs. H T uman immunodeficiency virus (HIV),* the causative agent of acquired immune deficiency syndrome (AIDS), is now known to be associated with a wide spectrum of clinical disease. Patients may remain clinically well, with only mildly abnormal immune function; alternatively, they may progress to severe clinical manifestations, which have been defined as AIDS. Between these two extremes. there are many clinical manifestations, including persistent generalized lymphadenopathy (PGL),2 thrombocytopenia,3 oral thrush,4 hairy leukoplakia5 and clinical and laboratory complexes such as AIDS-related complex (ARC)6 or lesser AIDS.7 It is currently not entirely clear to what degree these clinical manifestations are truly AIDS prodromes as opposed to stable manifestations of HIV infection. Most data that bear on this question have been derived from retrospective or cross-sectional analyses in which patients are grouped according to the clinical manifestation (e.g., PGL, ARC or AIDS) and then compared with regard to various behavioural, clinical and laboratory variables. Moreover, many of these early analyses did not take account of HIV antibody status, and manifestations such as PGL may have had a cause other than HIV infection.8'9 The ideal way of identifying variables that are predictive of AIDS is to prospectively monitor

*The retroviruses implicated as the causative agents of the acquired immune deficiency syndrome (AIDS) have been given several names, including lymphadenopathy-associated virus (LAV), human T-lymphotropic virus type III (HTL V-III), AIDSassociated retrovirus (ARV) and immunodeficiency-associated virus (IDA V), as well as combinations of the first two. Recently the Human Retrovirus Subcommittee of the Intemational Committee on the Taxonomy of Viruses proposed the name human immunodeficiency viruses (HIV) for all the closely related members of this group of viruses.' Until the scientific community agrees to use one term, CMAJ authors may use the tezrms that they prefer.-Ed. 882

CMAJ, VOL. 135, OCTOBER 15, 1986

HIV-seropositive people and then compare the distribution of the variables in those in whom AIDS develops and those in whom it does not. In the study population for our ongoing prospective study of homosexual men in Vancouver, 26 cases of AIDS have developed since November 1982. In this report we present a comparison of antecedent behavioural, clinical and laboratory findings in these patients and HIV-seropositive controls who remained AIDS-free. Methods The Vancouver Lymphadenopathy-AIDS Study has previously been described in detail.8-12 In summary, 726 homosexual men were recruited from six primary care practices in central Vancouver between November 1982 and February 1984. Study subjects have been returning for follow-up visits approximately every 6 months since their initial visit. A total of 500 subjects (69%) had completed their fifth visit as of February 1986. During each visit, participants complete a detailed, self-administered questionnaire on sexual practices, previous infections and illnesses, medications, illicit drug use and sexual contacts in AIDSendemic areas. Each participant undergoes a physical examination, including measurement of lymph node size. In addition, blood samples are drawn for immunologic and HIV antibody testing, as previously described.9 For lymphocyte subset analysis, 4.5 ml of whole blood was collected in sodium ethylenediaminotetraacetate (EDTA) Vacutainer tubes (Becton-Dickinson, Mountainview, California) and stored at room temperature for no more than 4 hours before analysis. The recommended volume of Leu-3a-PE (helper/inducer) and Leu 2a-FITC (suppressor/cytotoxic) monoclonal antibody (Becton-Dickinson) was added to 200 ,l of phosphate buffered saline (PBS) (Coulter Immunology, Hialeah, Florida) prepared according to the manufacturer's directions and 100l ,l of wellmixed whole blood. After incubation at room temperature for 10 minutes in the dark, the cells were washed twice with PBS. The cell button was vigorously vortexed, freshly prepared ImmunoLyse (Coulter) was added, and the cells were vortexed and incubated for 2 minutes. Coulter Fixative was added while the sample was vortexed, and the cell button was washed twice with PBS. Then 0.4 ml of 1°% paraformaldehyde (pH 7.4) was added to the cell button while it was vigorously vortexed. The labelled cells were stored in the dark at 4°C and analysed within 2 days. The percentages of Leu 3a-PE- and 2a-FITC-labelled lymphocytes were measured with an EPICS-C Flow Cytometer (Coulter Electronics Inc., Hialeah, Florida). The lymphocyte population was determined by forward- and right-angle light 'scatter. PE and FITC were excited at 488 nm at 500 mW. The instrument was standardized daily by measuring forward-

angle light scatter with Coulter fluorospheres while red and green fluorescence was monitored with Becton-Dickinson Calibrite microspheres. Fluorescent-labelled antibody subclass controls (BectonDickinson) were used to establish background fluorescence. The Leu 3a-PE population was measured by red fluorescence and the Leu 2a-FITC population by green fluorescence. 'Lymphocyte subset data obtained before January 1985 were derived from cells separated on Ficoll-Hypaque (Pharmacia [Canada] Inc., Dorval, PQ) and measured with an FACS IV Flow Cytometer (Becton-Dickinson), as previously described.9 To determine the comparability of the two methods, we analysed the lymphocyte subset results obtained by both methods for 66 patients. For purposes of comparison the FACS IV results were adjusted according to the derived linear regression formula % EPICS-C = 4.63 + 0.94 (% FACS IV) for the helper/inducer population and % EPICS-C = 5.27 + 0.71 (% FACS IV) for the suppressor/ cytotoxic lymphocyte population. Absolute lymphocyte subset results were calculated as the product of the percentage of the subset and the absolute lymphocyte count, as previously described.9 Cases of AIDS were defined according to the criteria of the Centers for Disease Control, Atlanta,13 and were diagnosed between May 1983 and February 1986. For each case we obtained the most complete antecedent set of laboratory data for analysis. Data on symptoms and physical findings were obtained from the office visit records corresponding to the date that the blood sample was drawn during the period January 1983 to February 1984. Data on sexual practices, previous infections and illnesses, medications, illicit drug use and sexual contacts in AIDS-endemic areas were obtained from the enrolment questionnaire. Seropositive controls were selected from our cohort according to the following criteria: HIV seropositive at initial visit and AIDS-free as of February 1986. Laboratory and clinical data for the controls were obtained from records for the third visit, which occurred between April 1984 and February 1985. Data on sexual practices, previous infections and illnesses, medications and so forth for the controls were obtained from the enrolment questionnaire. Generalized lymphadenopathy was defined as the presence of lymph nodes greater than 1 cm in diameter at two or more extrainguinal sites. Since information on symptoms (shortness of breath, night sweats, fever, diarrhea, cough, unintentional weight loss, thrush and herpes zoster) was not gathered until the second questionnaire, this information was complete for only 12 patients with AIDS. Univariate analyses were based on the methods of Mantel and Haenszel.1 Unadjusted relative risk estimates were computed with the odds ratio. Approximate 95% confidence intervals were computed with the test-based limits proposed by

Miettinen.'5 For symptoms and physical findings, p values were based on Fisher's exact test.16 For laboratory results, p values were based on the Wilcoxon rank sum test. All p values are twosided. For all comparisons, subjects with missing or unknown values were excluded from the analysis. During the initial phase of the study, lymphocyte subset testing was performed only in random subsamples of the cohort because of constraints on the availability of the necessary facilities. Results Of the 26 men with AIDS in the study cohort, 1 was enrolled just before the diagnosis of AIDS and has been omitted from this analysis. Of the 25 remaining patients (mean age at entry 34.7 years), 13 had cancer (Kaposi's sarcoma [10 patients] or lymphoma [3]) and 12 had opportunistic infections (Pneumocystis carinii pneumonia [9] or other [3]). The earliest laboratory and clinical data available for these cases preceded the diagnosis of AIDS by a mean of 17.5 months (extremes 1 and 36 months). Eighteen sets of results preceded the diagnosis of AIDS by more than 12 months and 23 by more than 6 months. A total of 80 men (mean age 32.5 years) met the criteria for seropositive controls. The dates of the laboratory and clinical results used for the controls were such that the men had remained AIDS-free for a mean of 16.7 months (extremes 12 and 22 months) after acquisition of their data. The results of antecedent laboratory tests for the patients with AIDS and the seropositive controls are presented in Table I. Significant differences were detected between the two groups in IgG level, IgA level, absolute number of helper T cells and ratio of helper to suppressor T cells. A difference of marginal significance was also found in hemoglobin concentration. Table II presents the results for antecedent generalized lymphadenopathy and symptoms. A significantly higher proportion of patients with AIDS than of seropositive controls had had generalized lymphadenopathy and two or more symptoms. These comparisons were based on limited numbers of observations, as explained in the methods section. The results for antecedent lifestyle variables are presented in Table III. An elevated number of male sexual partners in high-risk areas in the 5 years before enrolment was associated with a significantly increased risk of AIDS among seropositive subjects. Virtually all patients with AIDS (22/23) and controls (71/71) had an antecedent history of use of nitrite inhalants; no significant differences in dose or duration of use were detected between the two groups. Table IV presents the results for antecedent history of infectious disease. In no case was a significant difference detected between the two groups. CMAJ, VOL. 135, OCTOBER 15, 1986

883

.*1q.xspo-j8_4\|,'Dl!^iFfd;ehbrgSX:

time is likely the result of a progressive cytopathic effect of HIV infection.3" The mechanism of elevation of serum IgG and IgA levels is not proven but may involve loss of immune regulation and polyclonal proliferation of memory B cells,32 a response to Epstein-Barr virus33 or other viral infection,34 other antigenic challenges or direct lectin-like activation of B cells by HIV.35 Antecedent differences in leukocyte count, lymphocyte count, serum IgM levels and Clq binding were not detected between patients with AIDS and seropositive controls. These findings highlight the fact that many laboratory abnormalities may be a result of HIV infection alone and are not necessarily related to an additional pathophysi-

Discussion Abnormalities of immune function may be important in the identification of HIV-seropositive patients at high risk for AIDS. A number of studies have shown differences in results of tests of immune function, including lymphocyte subset counts, immunoglobulin levels and immune complex levels, in cross-sectional analyses comparing patients with AIDS, ARC or PGL and asymptomatic homosexual men.17-25 Few investigators have prospectively followed groups of subjects through progressively severe clinical manifestations, and only recently have such studies been adjusted for HIV antibody status.26-30 In this study we detected significantly higher serum IgG and IgA levels and lower absolute helper T-cell counts and ratios of helper to suppressor T cells in patients with AIDS a mean of 17.5 months before the diagnosis of the syndrome than in subjects who were consistently seropositive but AIDS-free for a similar length of time. The predictive value of these statistically significant differences may be limited. For example, our data suggest a positive likelihood ratio of only 1.8 for an absolute helper cell count below 400/ml in predicting eventual development of AIDS in our seropositive group. However, the helper T-cell count and ratio of helper to suppressor T cells often fell to even lower levels at times closer to the diagnosis of AIDS. Thus, the predictive value of a persistently low or falling helper T-cell count or ratio of helper to suppressor T cells in identifying patients at high risk for AIDS currently remains unknown. A decrease in helper T-cell count over

No. (and %) of No. (Wrd 76 of patients with serbpoitive

AIDS

Variable Generalized lymphadenopathy

6 (24) 19 (76)

Absent Present

Symptomst 8 (67) 4 (33)

5 -

w

i#;bvi,

AMd .~~~~~~~~~4

,.i;, £

.'?# ;i.

'......................t.t%i.!.^

7,

,

oll

884

CMAJ, VOL. 135, OCTOBER 15, 1986

i .

.-

I.A. ".

I

.1

f:jJ

j.. f

'i

M..,

.,

j_

' Ilq

u

.

C., p

.

i!e,

, _. jEft;

11

ologic abnormality associated with the development of AIDS. Generalized lymphadenopathy was significantly more frequent among the patients in whom AIDS eventually developed than in seropositive AIDS-free controls. It has previously been observed that patients with PGL appear to be at greater risk for AIDS. In two studies from New York, AIDS developed in 16.6% and 24% of subjects with PGL observed for 14 months36 and 40 months37 respectively. An incidence of AIDS of only 7% has been reported from San Francisco in a group of patients with PGL followed for a mean of 22 months.38 The inconsistent estimates may be due to different methods of patient selection. Of our seropositive controls, 51% had generalized lymphadenopathy as defined at a single point in time, and most remained clinically stable. Our findings support the concept that generalized lym-

phadenopathy is a disease manifestation that entails a greater risk of AIDS although it is not highly predictive. It has been noted that a decrease in lymph node size may precede AIDS.37,38 Although patients in whom AIDS developed had significantly more antecedent symptoms than

seropositive AIDS-free controls, no individual symptom or combination of symptoms was more frequent in the AIDS group than in the control group. Because the data on symptoms in the AIDS group were limited, these findings must be interpreted with caution. Recent reports suggest, however, that some signs or symptoms, such as hairy leukoplakia,5 oral thrush4 and complexes of signs and symptoms defined as ARC,' often precede AIDS as currently defined.13 We may have failed to detect such associations because our study was designed to analyse the most antecedent information available for these patients. The smaller num'Reaitive' -risk, laid 95% ss aespositv confdence cotosinterva [.Ci])

No. (andV%)of: patients with AIDS

Variable Number of male' se'xu"al pa'rtn'ers in lifetime