THE SYDNEY AIDS PROJECT: DEVELOPMENT OF ACQUIRED IMMUNODEFICIENCY SYNDROME IN A GROUP OF HIV SEROPOSITIVE HOMOSEXUAL MEN

The Sydney AIDS Project is a prospective immunoepidemiological study of 996 homosexual/bisexual men enrolled between February 1984 and January 1985. By January 1987, 32 of 386 homosexual men who were seropositive at enrolment in the study had developed AIDS, yielding a crude progression rate of between 2.8% and 4.2% per annum. Of these subjects, 23 (72%) developed AIDS within 12 months of enrolment.
In univariate analysis, the only lifestyle differences between seropositive subjects who progressed to AIDS and those that did not progress were less frequent oral sex activity and more use of marijuana in the three months prior to enrolment. In multivariate analysis, seropositive subjects who progressed to AIDS were more likely to have a lower percentage of CD4+ cells, a higher percentage of CD8+ cells and to have used marijuana in the three months prior to enrolment than the seropositive subjects who did not progress. No HIV seropositive subject who was asymptomatic and had normal T-cell subsets at enrolment had developed AIDS by January 1987. Persistent generalised lymphadenopathy was not associated with progression to AIDS.
Although there are a number of lifestyle factors that may be associated with HIV infection, this study did not implicate most of these in the progression of HIV seropositive subjects to end-stage AIDS. We conclude that antecedent changes in T-cell subsets are associated with progression to AIDS and we emphasise the prognostic value of enumeration of T-cell subsets in HIV seropositive persons. (Aust NZ J Med 1988; 18: 8–15).     

Human herpesvirus 8 cellular immune responses in homosexual men.

Little is known about cellular immunity to human herpesvirus 8 (HHV-8), the virus associated with Kaposi's sarcoma (KS). T cell proliferative responses to purified HHV-8 were measured in homosexual men, a group with elevated HHV-8 seroprevalence and high risk of KS. None of 20 blood donor controls had T cell responses to HHV-8. Among human immunodeficiency virus (HIV)-negative homosexual men, 8 (42%) of 19 HHV-8 seropositive men responded as did 4 (16%) of 25 HHV-8 seronegative men. Among HIV-positive homosexual men, however, none of 21 HHV-8 seropositives had T cell responses to HHV-8, even though most responded to common recall antigens, and 10 had >/=400 CD4 cells/mm3. The results suggest that HHV-8 T cell proliferative responses are common in HIV-negative homosexual men and that HIV infection may be associated with diminished HHV-8 cellular immunity, possibly before there is substantial depletion of CD4 cells. If correct, this could explain why KS occurs relatively early in HIV infection/AIDS.     

Effects of long-term seropositivity to human immunodeficiency virus in a cohort of homosexual men

The long-term effects of HIV infection were evaluated by comparing data from two visits a mean of 18 months apart in groups of 148 persistently seropositive and 287 persistently seronegative homosexual men. At each visit, the seropositive men exhibited lower CD4 counts, CD4/CD8 ratios, hemoglobin concentrations and lymphocyte counts, and higher C1q binding, IgG and IgA levels. More important, the decline of the CD4/CD8 ratio and the rise of the C1q binding, IgG and IgA, progressed significantly in the seropositive group between visits. Seropositive men were at elevated risk of developing constitutional symptoms and generalized lymphadenopathy. An association was present between development of symptoms and inversion of the CD4/CD8 ratio. The 11 seropositive men who have progressed to AIDS had lower CD4 counts and CD4/CD8 ratios, and higher C1q binding, IgG and IgA, than 134 seropositive AIDS-free men a mean of 21.4 months prior to diagnosis. The AIDS group demonstrated greater decline between visits in the CD4 count, hemoglobin and white blood count (WBC) than the seropositive AIDS-free group. The present data document the long-term effects of HIV infection in a seropositive cohort and suggest the possibility of a subgroup particularly susceptible to the progressive effects of HIV that precede the development of the acquired immunodeficiency syndrome (AIDS).     

Long-term seropositivity for human T-lymphotropic virus type III in homosexual men without the acquired immunodeficiency syndrome: development of immunologic and clinical abnormalities. A longitudinal study

The long-term effects of seropositivity for human T-lymphotropic virus type III (HTLV-III) on T-lymphocyte subsets and health status were evaluated in longitudinal studies of 250 initially healthy homosexual men. The relative risk of having an inverted T-lymphocyte helper-to-suppressor ratio rose from 14.3-fold among short-term seropositive subjects (less than 19 months) to 46.9-fold among long-term seropositive subjects (greater than 29 months) in comparison with the risk among seronegative subjects. Overall, 91.7% of long-term seropositive men had inverted ratios, compared with 12.9% of seronegative men. None of the seropositive men who developed an inverted ratio later reestablished a normal ratio. Both decreased T-helper cell number and percentage (p = 0.003) and increased T-suppressor cell number and percentage (p = 0.03) were significantly correlated with duration of seropositivity. Among seropositive persons, lymphadenopathy was a highly significant short-term as well as long-term consequence, whereas diarrhea, oral thrush, and herpes zoster were correlated with long-term seropositivity. Overall, 50% of long-term seropositive men compared with 16% of seronegative men developed at least one of five clinical symptoms (p less than 0.003). We conclude that a high proportion of persons infected with HTLV-III will develop measurable immunologic and clinical abnormalities.     

CLINICAL AND IMMUNOLOGIC SEQUELAE OF AIDS RETROVIRUS INFECTION

The Sydney AIDS Project is a prospective immunoepidemiological study of 911 homosexual and bisexual men enrolled between February 1984 and January 1985. Clinical, immunological, and serological studies are performed on these subjects every six months. At enrolment, 39.9% of subjects were seropositive for antibodies to AIDS retrovirus (ARV). Of these 352 seropositive subjects, 28.1% were symptomless with normal immune profiles, 23.6% were symptomless with an immunodeficiency, 18.8% had a clinical illness but normal immune profile, and 29.6% had a clinical illness and immunodeficiency. Of the symptomless subjects, 27.8% were seropositive for antibodies to ARV. Clinically, seropositivity was significantly associated with enlargement of three or more non-inguinal lymph node groups, splenomegaly, and hepatomegaly. Immunologically, seropositivity was significantly associated with lower absolute numbers of lymphocytes and T4 + lymphocytes and a lower T4 +:T8 + ratio, compared with seronegative subjects. Seropositive subjects with a clinical illness had a significantly lower percentage of T4 + lymphocytes and lower T4 +:T8 + ratio than did those who were symptomless. However, the absolute number of T4 + cells was not significantly different between subjects with a clinical illness and those who were symptomless. Subjects whose sera were positive by immunofluorescence and enzyme-linked immunosorbent assay but were negative by radioimmune precipitation assay had a lower number and percentage of T4 + lymphocytes than subjects who were positive by all three tests. These results demonstrate a wide variety of clinical and immunological responses to ARV infection. Prospective study of these subjects will enable us to define further the natural history of ARV infection and factors associated with progression.     

The prevalence of hairy leukoplakia in HIV seropositive and HIV seronegative immunocompromised patients.

The prevalence of hairy leukoplakia was determined among 176 symptomatic HIV seropositive patients seen at the outpatient department of the Institute of Tropical Medicine in Antwerp, Belgium. Moreover, systematic tongue biopsies were performed during postmortem examination of 21 patients with AIDS, 100 HIV seronegative immunocompromised patients with haematologic or other malignancies and 100 HIV seronegative non-immunocompromised patients who died at the University Hospital Antwerp. Hairy leukoplakia was observed in 52 (29.5%) of the outpatients, but only in one (5%) of the AIDS patients in the postmortem study (P = 0.03). An explanation for this difference may be that significantly more AIDS patients who died had received either acyclovir or ganciclovir during the 3 months prior to the postmortem examination than the HIV seropositive outpatients during the 3 months prior to examination. Hairy leukoplakia occurred more often in Caucasian homosexual men with HIV infection (38%) than among heterosexual Africans with HIV infection (17%) (P = 0.06). Hairy leukoplakia was observed in none of the HIV seronegative patients.     

Clinical and immunological follow-up of previously hospitalized HIV-2 seropositive patients in Bissau, Guinea-Bissau.

A follow-up study was done in Bissau on 113 HIV-2 seropositive patients and 97 HIV-2 seronegative patients 3-15 months after hospitalization. Follow-up totalled 63.5 person years for seropositive patients and 62 for seronegative patients. The mortality during the follow-up period was 43.3% among the seropositive patients (rate 72/100 person years; p.y.) and 25.8% among the seronegative patients (40/100 p. y.). Among 25 HIV-2 associated AIDS cases the mortality was 80% (rate 117/100 p. y.). The median survival time for the AIDS patients was 8 months. Among 48 HIV-2 seropositive patients who lacked signs or symptoms included in the WHO case definition for AIDS at the time of hospitalization 6 patients (12.5%) developed AIDS related symptoms (ARS) during altogether 31.5 person years of follow-up (rate 19/100 p. y.). Tuberculin anergy was demonstrated in 83.3% (15/18) of HIV-2 seropositive patients with AIDS or ARS, in 14.3% (6/42) of seropositive patients without HIV-related symptoms and in 6.9% (5/72) of seronegative patients. A low CD4 T-lymphocyte count in combination with a low CD4/CD8 T-cell ratio was found significantly more often in HIV-2 seropositive patients with AIDS or ARS (62.5%, 10/16) than in HIV-2 seropositive patients without HIV associated symptoms (6.9%, 2/29) or in seronegative patients (2.7%, 1/37). Thus the mortality among recently hospitalized HIV-2 seropositive patients was high and a high proportion of seropositive patients with HIV-related symptoms had evidence of immunodeficiency.     

Prevalence of human immunodeficiency virus type 1 DNA in hemophilic men and their sex partners. Hemophilia-AIDS Collaborative Study Group

Polymerase chain reaction (PCR) was used to detect human immunodeficiency virus (HIV)-1 DNA in peripheral blood mononuclear cells to assess in hemophilic men whether any were HIV-seropositive but uninfected or seronegative but infected and in seronegative sex partners of seropositive hemophilic men whether any were infected. Of 40 seropositive men, 38 (95%) were PCR-positive; one was PCR-indeterminate and one PCR-negative. None of 41 seronegative men who used only donor-screened, virus-inactivated coagulation factor products were PCR-positive. However, two of six who received noninactivated products were PCR-positive; one had low T-helper cell counts and died of unrelated causes and the other had seroconverted 11 mo later. PCR with a second primer pair also detected HIV-1 DNA in these two men. None of 25 seronegative female sex partners of seropositive men, including six men with AIDS and seven with AIDS-related symptoms, were PCR-positive. These data suggest that most seropositive hemophilic men are HIV-infected; whether some are infected with defective virus remains to be resolved as does the infection status of seropositive PCR-negative men. Identification of two seronegative PCR-positive men supports the possibility that HIV-1 DNA can be detected before seroconversion.     

Oral candida albicans in HIV infection

The prevalence of oral colonization with Candida albicans was studied in 225 homosexual men, 99 of whom had HIV antibodies and in 175 heterosexual men. Oral candidal carriage was most prevalent among HIV seropositive homosexual men (77.8%). Rich growth of C. albicans in culture and findings of pseudomycelial elements in oral mucosal smear also correlated with HIV seropositivity. Pseudomycelial forms of C. albicans were demonstrated in mucosal smear from all patients with oral mucosal lesions suspected for candidiasis. However, 26/53 patients (49.1%) with positive smear had no clinical signs of oral candidiasis. The oral yeast flora was sampled twice in 85 homosexual men at an interval of 12-18 months. 71/85 patients (83.5%) were grouped into the same category of candidal colonization; carrier or noncarrier state, on both occasions. No statistically significant differences in numbers of CD 4 cells or CD 8 cells were observed between patients with respect to candidal colonization, when HIV seropositive and seronegative homosexual men were considered separately.     

Pre-AIDS mortality and its association with HIV disease progression in haemophilic men, injecting drug users and homosexual men

OBJECTIVE: To study pre-AIDS mortality and its association with HIV disease progression in different exposure groups with known intervals of HIV seroconversion. DESIGN AND METHODS: The type and rate of pre-AIDS deaths were assessed in 111 HIV-infected haemophilic men followed in London, and 118 injecting drug users and 158 homosexual men followed in Amsterdam. In each group, the association between CD4+ T-cell count, HIV RNA and pre-AIDS mortality was studied using proportional hazards analysis. RESULTS: By 10 years after seroconversion 7.3% of the haemophilic men had died without AIDS and 38.2% had developed AIDS. These figures were 20.2 and 30.5% for injecting drug users, and 8.0 and 55.0% for homosexual men. The major causes of pre-AIDS mortality appear to differ in the three exposure groups. The risk of pre-AIDS death tended to increase with decreasing CD4 cell count and increasing HIV RNA levels in injecting drug users and homosexual men. In men with haemophilia the associations were less obvious, although the log-transformed CD4 cell count was predictive for pre-AIDS death. CONCLUSIONS: Pre-AIDS deaths occur and are at least partially related to HIV disease progression irrespective of how individuals became infected. Because of the longer life expectancy due to highly active antiretroviral therapy (HAART), pre-AIDS deaths are likely to show a further increase. Methods to incorporate these intermediate outcomes should be considered in the estimation of the size of the HIV epidemic and in the survival analysis of HIV-infected individuals. Prevention and treatment of non-AIDS infections, especially hepatitis C virus infection, and cancers will become increasingly important in HIV-infected individuals. The interaction between these therapies and HAART should be closely monitored.     

The development of AIDS or AIDS-related conditions in a cohort of HIV antibody-positive homosexual men during a 3-year follow-up period

One hundred and thirty-three homosexual men seropositive for the antibody against human immunodeficiency virus (HIV) were enrolled in a prospective study in 1984-85. The 3-year cumulative incidences of the acquired immunodeficiency syndrome (AIDS) and AIDS-related conditions, by life-table analyses, were 18% and 34%. The cumulative incidence of immune deficiency defined as CD4 lymphocytes less than 0.5 x 10(9) l-1 was 70% at 3 years. Absence of antibodies to p24 antigen, HIV antigenaemia, CD4 lymphocytes less than 0.3 x 10 l-1 and elevated serum level of IgA were significantly associated with the development of AIDS. There was no association between disease progression and persistent generalized lymphadenopathy. When adjusted to the probable year of infection, these results are in accordance with previous cohort studies. It is concluded that most, or all, subjects seropositive for HIV will develop progressive loss of CD4 lymphocytes followed by clinical signs of immune deficiency, and that differences among previous cohorts with respect to disease progression are probably due to differences in the duration of infection.     

Human immunodeficiency virus infection in hemophiliac patients. A three-year prospective evaluation

Thirty-seven heterosexual hemophiliac patients underwent prospective evaluation with clinical examinations, serologic studies for antibody to human immunodeficiency virus (HIV), and tests of immune function for an average of 37 months. At the time of entry into the study in 1982 to 1983, 18 subjects (49 percent) were already seropositive for HIV and 11 (30 percent) had persistent generalized lymphadenopathy. Seventy percent of the total population were clinically asymptomatic. In nine subjects, seroconversion occurred during the study such that 81 percent of the population was seropositive at the conclusion. During the same period, lymphadenopathy developed in six subjects, there was progression to AIDS-related complex (ARC) in four, and acquired immunodeficiency syndrome (AIDS) developed in one patient. Thus, at the end of the study, 54 percent were clinically asymptomatic, 32 percent had persistent lymphadenopathy, and 11 percent had ARC. Subjects who remained seronegative had received less factor concentrate than seropositive subjects, remained asymptomatic, and had normal results on tests of immune function. In those who had experienced seroconversion, there were decreased absolute numbers of CD4+ lymphocytes prior to seroconversion, and abnormalities of lymphocyte function developed after seroconversion. The development of persistent generalized lymphadenopathy was associated temporally with seroconversion. The presence of persistent generalized lymphadenopathy did not appear to be associated with an increased risk for AIDS in seropositive persons, since the condition of most hemophiliac patients with persistent generalized lymphadenopathy at the time of initial evaluation remained clinically and immunologically stable. In contrast to patients with persistent generalized lymphadenopathy, asymptomatic seropositive subjects had progressive abnormalities of lymphocyte function over time that were independent of the numbers of CD4+ cells in the peripheral blood.     

Immunological and virological markers in individuals progressing from seroconversion to AIDS

Six men were selected from a large cohort of homosexual men participating in a study on HIV infection that was followed from seroconversion to AIDS. The patients were studied retrospectively for immunological functions of T cells, T-cell subset distribution and biological phenotype of HIV. A severe decrease in anti-CD3 monoclonal antibody (MAb)-induced T-cell proliferation at seroconversion was observed in two out of six men. After this acute phase, CD4+ T-cell numbers were in the normal range in the early asymptomatic period; the proliferative response was subnormal, whereas the capacity to generate cytotoxic T cells (CTL) was normal. From seroconversion on, CD4+CD29+ memory T-cell numbers were decreased to approximately 50% of normal values, which may contribute to loss of T-cell reactivity. In the asymptomatic phase only slow-replicating non-syncytium-inducing HIV variants were observed. The T-cell proliferative response further declined with the depletion of naive CD4+ CD45RA+ T cells and CD4+ T-cell numbers started to decline. This second decrease in T-cell function coincided with the emergence of more rapidly replicating, often (four out of six) syncytium-inducing variants. At diagnosis of AIDS, T-cell proliferation and CD4+ T-cell numbers were extremely low in five out of six patients and CTL function had declined in three out of five individuals tested. Circulating CD8+ cells had gradually shifted to an immature CD38+CD28- phenotype. Our findings support the theory that HIV-induced immune dysfunction allows for the emergence of virulent HIV variants associated with CD4+ cell loss and disease.     

HIV-serology and lymphocyte subsets in relation to therapy and clinical development in haemophiliacs

389 Swedish patients with haemophilia A, B or von Willebrand's disease were examined for HIV-1 antibodies. T-cell subsets were measured in 260 of them. HIV-1 antibodies were found in 98 of these patients. Of the 199 patients with severe or moderate haemophilia A, 44% were seropositive. They had seroconverted between 1979 and 1983. HIV-1-seropositive patients had significantly decreased numbers of CD4 cells and increased numbers of CD8 cells. The seronegative haemophilia A patients had significantly increased numbers of CD8 cells. The T-cell subsets were followed for a median of 40 months in 73 seropositive patients. All groups of patients, at different clinical stages, showed decreasing numbers of CD4 cells. The most pronounced decrease was seen in the patients who developed AIDS, followed by the group which developed HIV-related signs or symptoms. HIV antigen in serum and antibody pattern in Western blot and ELISA were followed in 89 patients. HIV-1 antigen was present and p24 antibodies were lacking in 11% and 13% of asymptomatic subjects, in 13% and 20% of patients with persistent generalized lymphadenopathy, in 33% and 38% of patients with other HIV-related signs or symptoms and in 5/6 of the AIDS patients, respectively. In conclusion, the decrease of CD4 cells and the presence of HIV antigen and/or absence of p24 antibodies were found to be prognostic markers for HIV disease.     

PCR analysis of HIV-1 sequences and differential immunological features in seronegative and seropositive haemophiliacs

We have compared the immunological features of two matched groups of seronegative and seropositive haemophilia A individuals. Both groups were exposed from 1981 to 1985 to comparable amounts and batches of FVIII concentrates not subjected to virus inactivation procedures, and had therefore a 100% probability of receiving HIV-contaminated material. The presence of proviral HIV-1 sequences was evaluated by PCR in the DNA from peripheral blood lymphocytes and/or monocytes. After hybridization with specific probes, DNA from all seropositive haemophiliacs revealed HIV sequences; no HIV sequences were observed from the DNA of seronegative patients, even after two rounds of amplification, thus suggesting that these patients were not affected by a latent HIV infection. Seronegative/PCR- and seropositive/PCR+ patients showed a normal and reduced number of CD4+ lymphocytes, and a slight and marked increase of CD8+ cells respectively. Activated T cells expressing the HLA-DR antigen were elevated in both groups. Interestingly, a significant reduction of circulating CD56+/CD3- NK lymphocytes was observed only in seropositive haemophiliacs, whereas NK lymphocytes with CD56+/CD3+ phenotype were within normal levels in both groups. In seropositive patients no correlation was found between the number of CD4+ and CD56+/CD3- lymphocytes. The marked reduction of CD56+/CD3- lymphocytes observed in seropositive haemophiliacs in addition to the CD4+ cell depletion may represent a key pathogenetic factor which facilitates the onset and/or the progression of HIV-1 infection in haemophiliacs, and is related to the capacity of HIV to infect NK cells.     

Biphasic rate of CD4+ cell count decline during progression to AIDS correlates with HIV-1 phenotype.

OBJECTIVE: To determine the kinetics of decline of CD4+ lymphocytes in HIV-1-infected asymptomatic homosexual men. METHODS: CD4+ lymphocytes were enumerated in a cohort of 187 HIV-1-infected initially asymptomatic homosexual men seen at 3-month intervals over 5 years. During follow-up, 45 men progressed to AIDS (excluding cases presenting with Kaposi's sarcoma). Correlation between rate of CD4+ cell decline and presence of a particular HIV-1 biological phenotype was analysed in 43 participants. RESULTS: CD4+ cell counts declined slowly and continuously in HIV-1-seropositive men who remained asymptomatic during follow-up. A biphasic CD4+ cell count decline was observed in the group who developed AIDS: the decline was slow and steady (5.6 x 10(6)/l per month, similar to that observed in the asymptomatic group) until 18 months before AIDS diagnosis, but became three to five times faster thereafter. Rapid CD4+ cell decline was significantly related to syncytium-inducing, fast-replicating HIV-1 isolates; during the period of slow and steady CD4+ cell count decline, non-syncytium-inducing isolates were predominant. CONCLUSIONS: At an average of 18 months preceding AIDS diagnosis, a three to fivefold increase in the rate of loss of CD4+ lymphocytes occurs, and may be related to the appearance of a more virulent HIV-1 phenotype.     

Longitudinal patterns of HIV type 1 RNA among individuals with late disease progression

Longitudinal measurements of plasma HIV RNA were analyzed using novel segmented regression models for 62 men in the Multicenter AIDS Cohort Study who at enrollment in 1985 were HIV seropositive and who had stable CD4+ lymphocyte counts and no clinical disease progression for a 6-year period between 1985 and 1991. Through 1996, 20 of the men developed clinical AIDS or died (late progressors) and 42 remained asymptomatic (nonprogressors). Using segmented regression model methods, we estimated, for each individual, the time when a change in HIV RNA trajectory was most likely to have occurred. Prior to this time, late progressors and nonprogressors had stable plasma HIV RNA levels, although the mean level in late progressors was 0.42 log10 copies/ml higher than in nonprogressors (p = 0.018). Furthermore, late progressors showed significant increases in HIV RNA levels of 0.23 log10 copies/ml/year (1.7-fold increase/year). This increase in HIV RNA in the late progressors began approximately 1.1 years prior to the onset of their decline in CD4+ lymphocytes, and 4.8 years prior to the onset of AIDS. These results provide evidence that an increase in the slope of plasma levels of HIV RNA is a sign of incipient progression of HIV disease.     

Human T-lymphotropic virus type III in high-risk, antibody-negative homosexual men

A cohort of 215 asymptomatic homosexually active men from a Boston community health center are being prospectively followed to assess the natural history of the human T-lymphotropic virus type III (HTLV-III) infection. To determine if certain asymptomatic persons who are HTLV-III antibody negative may be viremic, an algorithm was developed that defined high-risk characteristics (a sexual partner with the acquired immunodeficiency syndrome [AIDS]; more than 100 homosexual partners; or leukopenia, lymphopenia, neutropenia, or thrombocytopenia). Of 33 asymptomatic homosexual men who did not have antibody to HTLV-III and whose cases have not been previously reported, 2 had HTLV-III recovered from their lymphocytes. Clinical, behavioral, and hematologic data from seronegative persons did not distinguish between those with negative or positive viral cultures. Asymptomatic carriage of HTLV-III in high-risk seronegative persons underscores the need to base preventive educational strategies and behavioral modification on the assessment of risk factors and not solely on the results of HTLV-III antibody screening.     

Serum vitamin B12 and transcobalamin levels in early HIV disease

A cohort of asymptomatic human immunodeficiency virus (HIV) seropositive patients was followed over a 2 1/2-year period, to establish changes in serum vitamin B₁₂ (B₁₂) concentrations. Serum B₁₂, CD4 count, and clinical progression to acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC) were measured. The unsaturated B12 binding capacities of the transcobalamins were also determined at the start of the study and compared to those from a homosexual HIV seronegative control group. The geometric mean of serum B₁₂ in 218 asymptomatic HIV seropositive patients was significantly lower than of a homosexual HIV seronegative control group (P = 0.02) and the unsaturated B₁₂ binding capacities of transcobalamins I and II were significantly higher in the asymptomatic patients compared with the same control group (P < 0.03, P < 0.0001, respectively). Fifty-nine of the asymptomatic HIV seropositive patients were followed over a 2 1/2-year period during which most had falling serum B₁₂ levels (64%). Twelve patients progressed clinically to ARC or AIDS, of which nine had repeat serum B₁₂ estimation prior to progression. All nine patients had or developed falling serum B₁₂ levels without any evidence of an HIV-related bowel disorder. All patients progressing had falling CD4 counts. Subnormal serum B₁₂ levels are common in HIV disease and occur at an early stage. B₁₂ levels fall in most patients with time and may help predict those patients whose disease will progress the most rapidly. © 1994 Wiley-Liss, Inc.     

Persistent alterations in the T-cell repertoires of HIV-1-infected and at-risk uninfected men

OBJECTIVE: We examined the association between immunogenic exposure and T-cell receptor (TCR) diversity to more clearly assess the impact of HIV-1 infection on the T-cell repertoire. METHODS:: To estimate the extent of T-cell clonality attributable to HIV-1 infection, we evaluated T-cell repertoires in low-risk and at-risk seronegative men and HIV-1 seropositive men by assessment of T-cell receptor beta-chain (TCR beta) complimentary determining region 3 (CDR3) lengths. RESULTS: The frequency of T-cell clonality in both HIV-1 infected and at-risk uninfected men was elevated in comparison to low-risk uninfected men. Among low-risk and at-risk seronegative, and HIV-1 seropositive men, clonal expansions were present in 3, 8, and 10% of CD4+ CDR3 lengths, and 18, 22, and 28% of CD8+ CDR3 lengths respectively. In addition, the longitudinal conservation of clonal expansions was observed in at-risk seronegative men. Based on comparisons to at-risk seronegative men, we estimate that at-risk seropositive men with chronic HIV-1 infection exhibit a 27% increase in the number of expanded CD8+ CDR3 lengths. CONCLUSION: These findings provide an approximation of the magnitude of the T-cell response in individuals undergoing chronic HIV-1 infection and demonstrate a significant association between the history of immunogenic challenge and the magnitude of clonality within the T-cell repertoire. In addition, these findings underscore the necessity of selecting controls with similar antigenic exposure histories when investigating T-cell dynamics in HIV-infected individuals.