Court Pedersen

Susceptibility to HIV infection and progression of AIDS in relation to variant alleles of mannose-binding lectin

BACKGROUND Low serum concentrations of mannose-binding lectin (MBL) are associated with increased susceptibility to recurrent infection. Three variant alleles in the MBL gene (B, C, and D), cause low serum concentrations of the protein. We investigated whether variant alleles of MBL affect susceptibility to infection with HIV and progression of AIDS. METHODS Between 1983 and 1986, all men who attended two clinics in Copenhagen for HIV screening were invited to take part in our study. We investigated the prevalence of variant alleles of MBL (detected by PCR) and assessed the prognostic value of these alleles and the corresponding serum MBL concentrations (measured by ELISA) in 96 homosexual men with HIV infection and in two control groups (123 healthy adults and 36 HIV-negative homosexual men at high risk of HIV infection because of their sexual behaviour). Follow-up was for up to 10 years. FINDINGS Eight (8%) of the HIV-infected men were homozygous for the variant MBL alleles compared with one (0.8%) of the healthy controls (p = 0.005) and none of the high-risk homosexual controls (p = 0.05). We found no significant association between MBL genotype and time from first positive HIV test to progression of AIDS (p = 0.8). However, in the 61 HIV-infected men who developed AIDS, the median survival time was significantly shorter after the AIDS diagnosis for men who were carriers of the variant alleles (both homozygous and heterozygous) than for men homozygous for the normal MBL allele (11 [IQR 4-21] vs 18 months [9-44], p = 0.007). Among men who developed AIDS, there was a significant difference in survival time between those with serum MBL concentrations below the lower quartile, those within the IQR, and those above the upper quartile (p = 0.02). Multivariate analysis showed that men who developed AIDS and had low serum MBL concentrations had an increased rate of rapid death, independently of CD4 T-cell counts at AIDS diagnosis. INTERPRETATION Our findings suggest that homozygous carriers of variant MBL alleles are at increased risk of HIV infection, either directly or indirectly because of increased susceptibility to coinfections. These alleles are also associated with a significantly shorter survival time after a diagnosis of AIDS.

Cerebral atrophy in AIDS: a stereological study

SummaryStereological estimates of mean volumes, surface areas, and cortical thicknesses were obtained on formalin-fixed brains from 19 men with AIDS and 19 controls. Volumes of neocortex, white matter, central brain nuclei, ventricles and archicortex were estimated using point counting and Cavalieris unbiased principle for volume estimation. In AIDS, the mean volume of neocortex was reduced by 11%, and that of the central brain nuclei by 18%. Mean ventricular volume was increased by 55%. Mean neocortical thickness was reduced by 12%. The mean volume of white matter was reduced by 13%. The findings in 6 clinically demented AIDS patients were not statistically different from the rest of the group.

Six billion neurons lost in AIDS

Human immunodeficiency virus type 1 (HIV1) is neurotropic. One of the morphological changes that is seen in patients with acquired immunodeficiency syndrome (AIDS) is cerebral atrophy affecting various structures including the neocortex. The cause of atrophy is not known. The total number of neocortical neurons was estimated in formalin fixed brains of 12 males with AIDS and 12 male controls matched for age and height. The mean number of neocortical neurons was 16.0times109 (coefficient of variation=0.11) in the AIDS patients compared with 21.9times109 (coefficient of variation=0.22) in the controls, a difference of approximately six billion (p<0.005, 2‐tailed). The global neuronal loss was 37%, and affected all four neocortical lobes. Ten patients did not have a history of central nervous system symptoms; two patients had a history of dementia. The number of neurons in the AIDS cases was not associated with dementia. AIDS is the first disease in which a global loss of neocortical neurons has been demonstrated using unbiased stereological methods. The loss of more than one third of the neurons may partly explain the cortical atrophy. Focal neuron loss has been reported by several authors, but none have been based on unbiased methods. In this group of AIDS patients the severe loss of neurons did not correspond to neurological deficits.

Isolation of HIV from cultures of purified CD4+ lymphocytes

Isolation of HIV from cultures of CD4+ lymphocytes purified from peripheral blood by indirect panning was optimized and evaluated. Infectious HIV was isolated by single isolation attempts in 98% of 102 HIV-antibody-positive patients (55 had AIDS or ARC and 47 were clinically healthy). The average culture time required for positive cultures was largely independent of the CD4 count of the patients and 87% of the positive isolation cultures from both groups of patients became positive within 14 days of culture. An evaluation of the possible influence of media additives on propagation of HIV showed that: amphotericin-B had a suppressive effect on HIV replication at concentrations recommended for anti-fungal activity; recombinant and human interleukin-2 were equally suitable for both isolation cultures and for propagation of HIV, and polybrene, at a concentration of 2 micrograms/ml in the culture medium had a beneficial effect.

Factors Associated with the CD4' Lymphocyte Count at Diagnosis of Acquired Immunodeficiency Syndrome

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, Kaposis sarcoma, and non-Hodgkins 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.

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

Abstract. 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 < 0.5 times 109 l−1 was 70% at 3 years. Absence of antibodies to p24 antigen, HIV antigenaemia, CD4 lymphocytes < 0.3 times 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.

One-year follow-up on the safety and efficacy of isoprinosine for human immunodeficiency virus infection

Abstract. The safety and clinical impact of isoprinosine in HIV‐infected individuals were assessed in a multicentre, randomized, double‐blind, 24‐week study phase, followed by an optional 24‐week open treatment phase, The results of the double‐blind phase have been reported. Of 866 HIV‐seropositive patients randomized, 832 subjects were eligible for efficacy analysis. On completion of the double‐blind phase, 596 patients started open treatment. All patients were evaluated with regard to progression to AIDS and/or death. Within 48 weeks, 10/412 (2.4%) patients assigned isoprinosine and 27/420 (6.4%) patients assigned placebo progressed to AIDS (P = 0.005). Intention‐to‐treat analysis showed identical results. Viewing the open treatment phase in isolation revealed no difference in progression rates between those treated and those not receiving the drug, perhaps reflecting the higher proportion of patients receiving zidovudine or PCP prophylaxis in the latter group. No severe adverse reactions or toxicities were observed. We conclude that HIV‐seropositive patients without AIDS may be safely and effectively treated with isoprinosine.

Isolation of HIV using T-lymphocyte panning: methodological aspects

A technique for isolation of HIV using selective cultures of T4 cells obtained from peripheral blood by immunochemical separation was developed and optimized. Using this method infectious virus could be isolated in single isolation attempts from 89% of 35 HIV-infected patients in different stages of immunodeficiency. This isolation frequency was virtually independent of the stage of the disease, in contrast to the results obtained by the conventional isolation technique based on peripheral mononuclear cells (PMC). It is concluded that isolation of HIV from selected T4 cells is superior to other methods when isolation is attempted from healthy HIV-infected individuals.

A comparison of three methods for detection of antibodies against the major core protein p24 of human immunodeficiency virus

The native major core protein p24 of the human immunodeficiency virus (HIV) was immunoaffinity purified by a monoclonal antibody and used to develop an indirect enzyme-linked immunosorbent assay (inELISA) for detecting p24 antibodies in human sera. Its ability to detect p24 antibodies was compared to that of the immunoblotting test (IBT) and a commercial available competition ELISA (compELISA) employing recombinant HIV core protein. In tests on 60 serum samples the overall agreement of the inELISA and the IBT was 93.3%. Fifty-two samples were p24 antibody positive in both the inELISA and the IBT and of these 24 (46.2%) were positive in the compELISA. All compELISA positive samples were derived from healthy individuals, whereas of the 28 (53.8%) compELISA negative samples 1 was from a patient with acute HIV infection, 18 from healthy individuals and 9 from ARC/AIDS patients. The compELISA was able to distinguish among healthy persons with normal or low T-helper cell count (P = 0.048), as was the inELISA when p24 antibodies were titrated (P = 0.027). The inELISA equals IBT in specificity and sensitivity, is convenient and is very suitable for titration of p24 antibodies.

HIV Neutralizing Antibodies: Development and Association with HIV Related Disease

Serum neutralization was measured in 72 sera collected during a 5.5-year period from 10 HIV infected individuals. Neutralizing antibodies (NA) were present in all sera. NA titers ranging from greater than 40 to greater than 640 were detected in sera from 4 patients, who all remained healthy and further an increase with time of NA was observed in these 4 patients. Progression to disease was observed in 3 persons with NA titers less than or equal to 40 who also lacked or lost anti-gag antibodies. Two of these patients were HIV antigenaemic prior to development of disease, whereas antigen was not detected in the remaining 7 healthy persons. A weak positive correlation (R(S) = +0.643, p less than 0.001) was found between titers of NA and whole virus antibody (WVA), with the ratios between titers (NA titer/WVA titer) varying a 100-fold. The results suggest that the presence of NA in some cases might be related to a healthy carrier state and that a combination of low titer NA with decline of anti-gag antibodies and/or HIV antigenaemia is associated with progression to clinical disease.