James J. Goedert

Genetic Restriction of HIV-1 Infection and Progression to AIDS by a Deletion Allele of the CKR5 Structural Gene

The chemokine receptor 5 (CKR5) protein serves as a secondary receptor on CD4+ T lymphocytes for certain strains of human immunodeficiency virus-type 1 (HIV-1). The CKR5 structural gene was mapped to human chromosome 3p21, and a 32-base pair deletion allele (CKR5Δ32) was identified that is present at a frequency of ∼0.10 in the Caucasian population of the United States. An examination of 1955 patients included among six well-characterized acquired immunodeficiency syndrome (AIDS) cohort studies revealed that 17 deletion homozygotes occurred exclusively among 612 exposed HIV-1 antibody-negative individuals (2.8 percent) and not at all in 1343 HIV-1-infected individuals. The frequency of CKR5 deletion heterozygotes was significantly elevated in groups of individuals that had survived HIV-1 infection for more than 10 years, and, in some risk groups, twice as frequent as their occurrence in rapid progressors to AIDS. Survival analysis clearly shows that disease progression is slower in CKR5 deletion heterozygotes than in individuals homozygous for the normal CKR5 gene. The CKR5Δ32 deletion may act as a recessive restriction gene against HIV-1 infection and may exert a dominant phenotype of delaying progression to AIDS among infected individuals.

Genetic variation in IL28B and spontaneous clearance of hepatitis C virus

Hepatitis C virus (HCV) infection is the most common blood-borne infection in the United States, with estimates of 4 million HCV-infected individuals in the United States and 170 million worldwide. Most (70–80%) HCV infections persist and about 30% of individuals with persistent infection develop chronic liver disease, including cirrhosis and hepatocellular carcinoma. Epidemiological, viral and host factors have been associated with the differences in HCV clearance or persistence, and studies have demonstrated that a strong host immune response against HCV favours viral clearance. Thus, variation in genes involved in the immune response may contribute to the ability to clear the virus. In a recent genome-wide association study, a single nucleotide polymorphism (rs12979860) 3 kilobases upstream of the IL28B gene, which encodes the type III interferon IFN-λ3, was shown to associate strongly with more than a twofold difference in response to HCV drug treatment. To determine the potential effect of rs12979860 variation on outcome to HCV infection in a natural history setting, we genotyped this variant in HCV cohorts comprised of individuals who spontaneously cleared the virus (n = 388) or had persistent infection (n = 620). We show that the C/C genotype strongly enhances resolution of HCV infection among individuals of both European and African ancestry. To our knowledge, this is the strongest and most significant genetic effect associated with natural clearance of HCV, and these results implicate a primary role for IL28B in resolution of HCV infection.

Epistatic interaction between KIR3DS1 and HLA-B delays the progression to AIDS.

Natural killer (NK) cells provide defense in the early stages of the innate immune response against viral infections by producing cytokines and causing cytotoxicity. The killer immunoglobulin-like receptors (KIRs) on NK cells regulate the inhibition and activation of NK-cell responses through recognition of human leukocyte antigen (HLA) class I molecules on target cells KIR and HLA loci are both highly polymorphic, and some HLA class I products bind and trigger cell-surface receptors specified by KIR genes. Here we report that the activating KIR allele KIR3DS1, in combination with HLA-B alleles that encode molecules with isoleucine at position 80 (HLA-B Bw4-80Ile), is associated with delayed progression to AIDS in individuals infected with human immunodeficiency virus type 1 (HIV-1). In the absence of KIR3DS1, the HLA-B Bw4-80Ile allele was not associated with any of the AIDS outcomes measured. By contrast, in the absence of HLA-B Bw4-80Ile alleles, KIR3DS1 was significantly associated with more rapid progression to AIDS. These observations are strongly suggestive of a model involving an epistatic interaction between the two loci. The strongest synergistic effect of these loci was on progression to depletion of CD4+ T cells, which suggests that a protective response of NK cells involving KIR3DS1 and its HLA class I ligands begins soon after HIV-1 infection.

Effect of Early versus Deferred Antiretroviral Therapy for HIV on Survival

BACKGROUND The optimal time for the initiation of antiretroviral therapy for asymptomatic patients with human immunodeficiency virus (HIV) infection is uncertain. METHODS We conducted two parallel analyses involving a total of 17,517 asymptomatic patients with HIV infection in the United States and Canada who received medical care during the period from 1996 through 2005. None of the patients had undergone previous antiretroviral therapy. In each group, we stratified the patients according to the CD4+ count (351 to 500 cells per cubic millimeter or >500 cells per cubic millimeter) at the initiation of antiretroviral therapy. In each group, we compared the relative risk of death for patients who initiated therapy when the CD4+ count was above each of the two thresholds of interest (early-therapy group) with that of patients who deferred therapy until the CD4+ count fell below these thresholds (deferred-therapy group). RESULTS In the first analysis, which involved 8362 patients, 2084 (25%) initiated therapy at a CD4+ count of 351 to 500 cells per cubic millimeter, and 6278 (75%) deferred therapy. After adjustment for calendar year, cohort of patients, and demographic and clinical characteristics, among patients in the deferred-therapy group there was an increase in the risk of death of 69%, as compared with that in the early-therapy group (relative risk in the deferred-therapy group, 1.69; 95% confidence interval [CI], 1.26 to 2.26; P<0.001). In the second analysis involving 9155 patients, 2220 (24%) initiated therapy at a CD4+ count of more than 500 cells per cubic millimeter and 6935 (76%) deferred therapy. Among patients in the deferred-therapy group, there was an increase in the risk of death of 94% (relative risk, 1.94; 95% CI, 1.37 to 2.79; P<0.001). CONCLUSIONS The early initiation of antiretroviral therapy before the CD4+ count fell below two prespecified thresholds significantly improved survival, as compared with deferred therapy.

Increased risk of noncardia gastric cancer associated with proinflammatory cytokine gene polymorphisms

BACKGROUND & AIMS Genetic variations in proinflammatory and anti-inflammatory cytokine genes influence individual response to carcinogenic exposures. Polymorphisms in interleukin (IL)-1 beta and its endogenous receptor antagonist are associated with risk of Helicobacter pylori-related gastric cancer. The aim of this study was to evaluate the role of proinflammatory cytokine gene polymorphisms in gastric and esophageal cancers defined by anatomic subsite. METHODS We assessed polymorphisms of the IL-1 gene cluster and 4 other cytokine genes in a population-based case-control study of upper gastrointestinal cancers, including gastric cardia (n = 126) and noncardia adenocarcinoma (n = 188), esophageal squamous cell carcinoma (n = 53), and adenocarcinoma (n = 108), and frequency-matched controls (n = 212). ORs for the different cancers were computed from logistic regression models adjusted for potential confounding factors. RESULTS Proinflammatory genotypes of tumor necrosis factor alpha and IL-10 were each associated with more than doubling of the risk of noncardia gastric cancer. Carriage of multiple proinflammatory polymorphisms of IL-1B(o) IL-1 receptor antagonist, tumor necrosis factor A, and IL-10 conferred greater risk, with ORs (and 95% confidence intervals) of 2.8 (1.6-5.1) for one, 5.4 (2.7-10.6) for 2, and 27.3 (7.4-99.8) for 3 or 4 high-risk genotypes. In contrast, these polymorphisms were not consistently related to the risks of esophageal or gastric cardia cancers. Polymorphisms in IL-4 and IL-6 were not associated with any of the cancers studied. CONCLUSIONS A proinflammatory cytokine genetic profile increases the risk of noncardia gastric adenocarcinoma but not other upper gastrointestinal cancers, possibly by inducing a hypochlorhydric and atrophic response to gastric H. pylori infection.

Spectrum of AIDS-associated malignant disorders

BACKGROUND To clarify which types of cancer result from AIDS, we compared the cancer experiences of people with AIDS with those of the general population by matching population-based cancer and AIDS registries in the USA and Puerto Rico. METHODS We used a probabilistic matching algorithm to compare names, birth dates, and, where available, social-security numbers of 98,336 people with AIDS and 1,125,098 people with cancer aged less than 70 years. We defined AIDS-related cancers as those with both significantly raised incidence post-AIDS and increasing prevalence from 5 years pre-AIDS to 2 years post-AIDS. FINDINGS Among people with AIDS, we found 7028 cases of Kaposis sarcoma (KS), 1793 of non-Hodgkin lymphoma (NHL), and 712 other cases of histologically defined cancer. Incidence rates among people with AIDS were increased 310-fold for KS, 113-fold for NHL, and 1.9-fold (95% CI 1.5-2.3) for other cancers. Of 38 malignant disorders other than KS and NHL, only angiosarcoma (36.7-fold), Hodgkins disease (7.6-fold), multiple myeloma (4.5-fold), brain cancer (3.5-fold), and seminoma (2.9-fold) were raised and increasing significantly (p<0.02) from the pre-AIDS to the post-AIDS period. INTERPRETATION Interpretation is complicated by screening and shared risk factors, such as sexual behaviour and cigarette smoking. However, our data indicate that AIDS leads to a significantly increased risk of Hodgkins disease, multiple myeloma, brain cancer, and seminoma. Immunological failure to control herpes or other viral infections may contribute to these malignant diseases.

Trends in cancer risk among people with AIDS in the United States 1980-2002.

Background:People with AIDS have heightened cancer risk from immunosuppression. HAART has been available since 1996 and has reduced AIDS-related mortality, but there are few large-scale studies on cancer trends. Methods:AIDS and cancer registries in 11 US regions (1980–2002) were used to identify cancers in 375 933 people with AIDS. Cancer risk relative to the general population was measured using the standardized incidence ratio (SIR), focusing on the 2 years after AIDS onset for those with AIDS in 1990–1995 and 1996–2002 (HAART era). Time trends were assessed with Poisson regression. Results:Between 1990–1995 and 1996–2002, risk declined for the two major AIDS-defining cancers: Kaposi sarcoma [(KS) n = 5131; SIR, 22 100 and 3640, respectively; P < 0.0001] and non-Hodgkin lymphoma [(NHL) n = 3412; SIR, 53.2 and 22.6, respectively; P < 0.0001]. Declines began in the 1980s, but risk fell sharply in 1996 and was stable thereafter. Risk of cervical cancer did not change (n = 64; SIR, 4.2 and 5.3, respectively; P = 0.33). Among non-AIDS malignancies, lung cancer was most common, but risk declined between 1990–1995 and 1996–2002 (n = 344; SIR, 3.3 and 2.6, respectively; P = 0.02). Risk of Hodgkin lymphoma increased substantially over the 1990–2002 period (n = 149; SIR, 8.1 and 13.6, respectively; P = 0.003). Conclusions:Dramatic declines in KS and NHL were temporally related to improving therapies, especially introduction of HAART, but those with AIDS remain at marked risk. Among non-AIDS-related cancers, a recent increase in Hodgkin lymphoma was observed.

Innate partnership of HLA-B and KIR3DL1 subtypes against HIV-1

Allotypes of the natural killer (NK) cell receptor KIR3DL1 vary in both NK cell expression patterns and inhibitory capacity upon binding to their ligands, HLA-B Bw4 molecules, present on target cells. Using a sample size of over 1,500 human immunodeficiency virus (HIV)+ individuals, we show that various distinct allelic combinations of the KIR3DL1 and HLA-B loci significantly and strongly influence both AIDS progression and plasma HIV RNA abundance in a consistent manner. These genetic data correlate very well with previously defined functional differences that distinguish KIR3DL1 allotypes. The various epistatic effects observed here for common, distinct KIR3DL1 and HLA-B Bw4 combinations are unprecedented with regard to any pair of genetic loci in human disease, and indicate that NK cells may have a critical role in the natural history of HIV infection.

Cancer risk in people infected with human immunodeficiency virus in the United States.

Data are limited regarding cancer risk in human immunodeficiency virus (HIV)‐infected persons with modest immunosuppression, before the onset of acquired immunodeficiency syndrome (AIDS). For some cancers, risk may be affected by highly active antiretroviral therapy (HAART) widely available since 1996. We linked HIV/AIDS and cancer registries in Colorado, Florida and New Jersey. Standardized incidence ratios (SIRs) compared cancer risk in HIV‐infected persons (initially AIDS‐free) during the 5‐year period after registration with the general population. Poisson regression was used to compare incidence across subgroups, adjusting for demographic factors. Among 57,350 HIV‐infected persons registered during 1991–2002 (median CD4 count 491 cells/mm3), 871 cancers occurred during follow‐up. Risk was elevated for Kaposi sarcoma (KS, SIR 1,300 [n = 173 cases]), non‐Hodgkin lymphoma (NHL, 7.3 [n = 203]), cervical cancer (2.9 [n = 28]) and several non‐AIDS‐defining malignancies, including Hodgkin lymphoma (5.6 [n = 36]) and cancers of the lung (2.6 [n = 109]) and liver (2.7 [n = 14]). KS and NHL incidence declined over time but nonetheless remained elevated in 1996–2002. Incidence increased in 1996–2002 compared to 1991–1995 for Hodgkin lymphoma (relative risk 2.7, 95%CI 1.0–7.1) and liver cancer (relative risk infinite, one‐sided 95%CI 1.1‐infinity). Non‐AIDS‐defining cancers comprised 31.4% of cancers in 1991–1995, versus 58.0% in 1996–2002. For KS and NHL, risk was inversely related to CD4 count, but these associations attenuated after 1996. We conclude that KS and NHL incidence declined markedly in recent years, likely reflecting HAART‐related improvements in immunity, while incidence of some non‐AIDS‐defining cancers increased. These trends have led to a shift in the spectrum of cancer among HIV‐infected persons.

A Prospective Study of Human Immunodeficiency Virus Type 1 Infection and the Development of AIDS in Subjects with Hemophilia

We evaluated a multicenter cohort of 1219 subjects with hemophilia or related disorders prospectively, focusing on 319 subjects with documented dates of seroconversion to human immunodeficiency virus type 1 (HIV-1). The incidence rate of the acquired immunodeficiency syndrome (AIDS) after seroconversion was 2.67 per 100 person-years and was directly related to age (from 0.83 in persons 1 to 11 years old up to 5.66 in persons 35 to 70 years old; Ptrend = 0.00003). The annual incidence of AIDS ranged from zero during the first year after seroconversion to 7 percent during the eighth year, with eight-year cumulative rates (+/- SE) of 13.3 +/- 5.3 percent for ages 1 to 17, 26.8 +/- 6.4 percent for ages 18 to 34, and 43.7 +/- 16.4 percent for ages 35 to 70. Serial immunologic and virologic markers (total numbers of CD4 lymphocytes, presence of serum interferon or HIV-1 p24 antigen, and low or absent serum levels of anti-p24 or anti-gp120) predicted a high risk for the subsequent development of AIDS. Adults 35 to 70 years old had a higher incidence of low CD4 counts than younger subjects (P less than or equal to 0.005), whereas adolescents had a low rate of anti-p24 loss (P = 0.0007) and subjects 1 to 17 years old had a lower incidence of AIDS after loss of anti-p24 (P = 0.03). These findings not only demonstrate that the risk of AIDS is related directly to age but also suggest that older adults are disproportionately affected during the earlier phases of HIV disease, that adolescents may have a low replication rate of HIV, and that children and adolescents may tolerate severe immunodeficiency better because they have fewer other infections or because of some unmeasured, age-dependent cofactor or immune alteration in the later phase of HIV disease.