Human immunodeficiency virus infection in pregnancy

The incidence and prevalence of human immunodeficiency virus (HIV) infection in women of child-bearing age continue to increase both internationally and in Canada. The care of HIV-infected pregnant women is complex, and multiple issues must be addressed, including the current and future health of the woman, minimization of the risk of maternal-infant HIV transmission, and maintenance of the well-being of the fetus and neonate. Vertical transmission of HIV can occur in utero, intrapartum and postpartum, but current evidence suggests that the majority of transmission occurs toward end of term, or during labour and delivery. Several maternal and obstetrical factors influence transmission rates, which can be reduced by optimal medical and obstetrical care. Zidovudine therapy has been demonstrated to reduce maternal-infant transmission significantly, but several issues, including the short and long term safety of antiretrovirals and the optimal use of combination antiretroviral therapy in pregnancy, remain to be defined. It is essential that health care workers providing care to these women fully understand the natural history of HIV disease in pregnancy, the factors that affect vertical transmission and the management issues during pregnancy. Close collaboration among a multidisciplinary team of knowledgeable health professionals and, most importantly, the woman herself can improve both maternal and infant outcomes.     

Human immunodeficiency virus and respiratory infection

Pulmonary disease remains a major problem for the 33 million individuals who are thought to be infected with human immunodeficiency virus (HIV) worldwide. Respiratory infections are responsible for a large number of the 2 million deaths that occur each year in association with HIV disease. In countries where the majority of the population can access highly active antiretroviral therapy, morbidity and mortality rates have been cut by up to 80%. This has allowed the withdrawal of specific opportunistic infection prophylaxis when immune restoration is deemed to be adequate. Recommendations have been published concerning Pneumocystis carinii prophylaxis. This year has also seen further reports of drug-resistant isolates of Pneumocystis carinii. The clinical relevance of this is still debated. Tuberculosis remains a global problem. The complexity of the interactions between specific anti-HIV and anti-tuberculous treatment have been highlighted. In the developing world, the importance of immunization and prophylaxis (against bacteria and mycobacteria) have recently been further defined in a number of studies.     

Identification of a novel human immunodeficiency virus strain cytopathic to megakaryocytic cells

Impaired megakaryocytopoiesis may be a contributing factor to thrombocytopenia associated with human immunodeficiency virus (HIV) infection. Because HIV isolates differ in their host range and pathogenicity, we investigated whether HIV strains with demonstrable cell tropism and increased cytopathicity for megakaryocytes could be derived from the blood of thrombocytopenic HIV-infected individuals. We derived a strain, HIV-WW, from the peripheral blood of an individual with severe thrombocytopenia and found the virus to be highly and specifically cytotoxic to CMK and DAMI megakaryocytic cells. CMK and DAMI cells were not permissive for the virus and HIV-WW induced cytopathicity for these megakaryocytic cells did not depend on viral replication. The CD4 N-terminus-binding domain of the HIV gp120 envelope protein did not appear to be involved in determining the cytopathic phenomenon. HIV may impair megakaryocytopoiesis through interactions at the cell surface in some cases rather than through viral entry and intracellular replication.     

Human immunodeficiency virus infection in tuberculosis patients

Human immunodeficiency virus (HIV) serology was performed in non-Asian-born patients 18-65 years old with newly diagnosed tuberculosis at a county tuberculosis clinic, and demographic and clinical features of HIV-seropositive and HIV-seronegative patients were compared. Sixty of 128 eligible patients agreed to participate, of whom 17 (28%) were seropositive. Risk of HIV was associated with homosexual contact, intravenous drug use, or both; however, 4 (24%) of the 17 seropositives denied risk behaviors. Significantly more blacks (48%) than whites (10%) or Latinos (20%) were HIV-seropositive (P less than .01). Site of disease, tuberculin reactivity, response to therapy, drug toxicity, and relapse did not differ significantly between groups. HIV-seropositive patients had significantly lower median CD4+ cell counts (326/mm3, range 23-742/mm3, vs. 929/mm3, range 145-2962/mm3, P less than .0005) and median CD4+:CD8+ ratios (0.50, range 0.14-1.07 vs. 1.54, range 0.35-4.36, P less than .0001). HIV infection is associated with clinically typical tuberculosis and HIV screening of tuberculosis patients is recommended in areas where HIV is endemic.     

Human immunodeficiency virus infection and the liver

Liver disease in human immunodeficiency virus(HIV)-infected individuals encompasses the spectrum from abnormal liver function tests,liver decompensation,with and without evidence of cirrhosis on biopsy,to non-alcoholic liver disease and its more severe form,non-alcoholic steatohepatitis and hepatocellular cancer.HIV can infect multiple cells in the liver,leading to enhanced intrahepatic apoptosis,activation and fibrosis.HIV can also alter gastro-intestinal tract permeability,leading to increased levels of circulating lipopolysaccharide that may have an impact on liver function.This review focuses on recent changes in the epidemiology,pathogenesis and clinical presentation of liver disease in HIV-infected patients,in the absence of co-infection with hepatitis B virus or hepatitis C virus,with a specific focus on issues relevant to low and middle income countries.     

Human immunodeficiency virus infection and renal failure

Renal manifestations are an important component of HIV disease. Renal disease significantly contributes to morbidity and mortality in patients with HIV. Great progress has been made in identifying specific glomerular lesions and its pathogenesis. Newer antiretroviral agents offer great promise in preventing renal disease and also in patients with established HIVAN. Survival of patients with HIV and ESRD (irrespective of cause) who are receiving RRT continues to improve over the years. Acute reversible renal failure, a preventable complication, is also declining in hospitalized HIV patients. More and more physicians, who in the past were reluctant to care for patients with HIV and renal failure because of grim prognosis, are now becoming familiar with the renal sequelae and are encouraged by recent favorable results. As knowledge about viruses is expanding, the proper use of newer highly effective antiretroviral and other agents in complicated patients should further improve both the survival and quality of life in patients with HIV infection and renal disease.     

Human immunodeficiency virus infection and the intestine

HIV is a retrovirus infecting CD4-positive cells causing profound immunosuppression, eventually clinically manifest as AIDS. The cells principally infected by HIV are T4 lymphocytes (helper) and macrophages. The eventual loss of helper cell function is the prime reason for immunodeficiency which renders the individual susceptible to opportunistic infections. HIV infection was first described in male homosexuals. However, the trend now is for seroprevalence to rise rapidly in intravenous drug abusers in the West. In addition, African AIDS is thought to be almost exclusively heterosexual in nature, a paradox which is not yet fully explained in comparison with the relatively low but increasing incidence in heterosexuals in the Western world. Virtually every organ system in the body can be affected clinically during the course of HIV infection. The gastrointestinal tract is a major target, and the physiological sequelae are an important cause of morbidity and mortality. The pathophysiology of intestinal infection is not yet fully understood, however two main mechanisms have been postulated. The first is reduced intestinal immunity resulting in chronic opportunistic infections, which themselves caused altered intestinal function. The second is that HIV itself affects the intestinal mucosa, causing malfunction. The mechanisms by which the latter occurs are controversial but may result from either direct infection of mucosal epithelial cells or macrophages within the mucosa. Reports have documented the presence of HIV genome in both epithelial argentachromaffin cells and macrophages. In addition, profound degeneration of intrinsic jejunal autonomic neurones has been demonstrated, but the functional significance of such denervation is as yet unknown. The clinical stage of HIV infection at which intestinal mucosal immunity fails is by definition when opportunistic infection occurs (that is, clinical progression to stage IV disease), namely AIDS, however a detailed knowledge of the mechanisms of intestinal immune failure are lacking.     

Human immunodeficiency virus infection of enterocytes and mononuclear cells in human jejunal mucosa

Intestinal malabsorption is a recognized cause of malnutrition in patients infected with human immunodeficiency virus. However, the relationships among human immunodeficiency virus infection, morphological changes in the intestine, and development of intestinal malabsorption are not well established. Nine patients infected with human immunodeficiency virus underwent tests of intestinal absorption and jejunal biopsies for morphometric measurements, enzyme assays, and virus detection by in situ hybridization. Steatorrhea and low lactase activities were found in more than 85% of the patients. All biopsy specimens were abnormal with reversal of the ratio of villus length to crypt depth in seven and enlarged enterocyte nuclear size in nine. Human immunodeficiency virus was detected in five jejunal biopsy specimens, within villus enterocytes of one patient who had the most severe malabsorption of the group and in four other biopsy specimens in mononuclear infiltrating cells of the lamina propria. These results suggest that human immunodeficiency virus infection of the small intestinal mucosa is an early event that is associated with altered enterocyte differentiation and function.     

Human immunodeficiency virus infection and systolic myocardial performance

Cardiac dysfunction in HIV-infected patients is being increasingly recognized. The present echocardiographic and Doppler study was undertaken to evaluate left ventricular (LV) systolic performance during the different stages of the disease. Twenty-nine anti-HIV (positive (+) ambulatory patients (19 with AIDS and 10 with asymptomatic HIV infection) without cardiac symptoms were evaluated by two-dimensional and M-mode echocardiography. Four groups were identified: group A, 10 patients (9 without AIDS) with a normal echocardiogram; group B, 6 patients with LV dilatation but normal LV function; group C, 9 patients with abnormal regional contractility but normal global function; group D, 4 patients with dilated cardiomyopathy (DC). Doppler study of the aortic systolic flow was performed in the four groups and in a normal control group. Doppler parameters—peak aortic velocity, ejection time, and flow velocity integral—were similar in controls and in groups A and B. Groups C and D (with abnormal contractility by echocardiography) had lower values for all Doppler parameters and were significantly different from controls and from groups A and B. Patients with dilated cardiomyopathy (group D) had the lowest values for all Doppler data, consistent with their low systolic performance. This group also had the lowest CD4+ lymphocyte counts and the longest mean probable time of HIV infection (6.5 years), being significantly different from group A patients, who presented a mean probable time of infection of 2.7 years and higher CD4+ counts. The results confirm that myocardial dysfunction affecting HIV-infected patients is more common in the late stages of the disease. It is also shown that Doppler study of the aortic systolic flow relates more closely to global LV performance than conventional echocardiography alone, and better differentiates patients with normal from those with abnormal LV function.Presented at the 35th World Congress, International College of Angiology, Copenhagen, Denmark, July 1993     

Human immunodeficiency virus infection and hepatitis C pathology

ABSTRACT: To investigate the possible influence of human immunodeficiency virus (HIV) infection on hepatitis C virus-related liver disease, liver morphology was evaluated in 160 HBsAg-negative patients with chronic hepatitis C, including 68 HIV-positive and 92 HIV-negative cases. No differences were detected in the severity of necro-inflammatory hepatic lesions between HIV-negative and HIV-positive patients when the CD4+ lymphocytes count exceeded 400 cells/mm³. In contrast, HIV-positive patients with CD4+ lymphocytes below 400/mm³ showed a significantly lower grade of portal inflammation and piecemeal necrosis. These results suggest that liver lesions in hepatitis C may largely depend on immunomediated mechanisms.     

Human immunodeficiency virus infection and the thyroid.

Abnormalities of thyroid function are associated with a number of systemic conditions, including patients infected with human immunodeficiency virus (HIV). Most patients with early HIV infection and a stable body weight have normal thyroid function. Subtle abnormalities of a number of thyroid function tests have been reported during the early asymptomatic phase of HIV disease. These include an inappropriately normal triiodothyronine (T(3)) and reduced reverse triiodothyronine (rT(3)), and increased thyroxine-binding globulin (TBG) levels. Opportunistic infections involving the thyroid gland, neoplasms such as lymphoma and Kaposi's sarcoma, and medications can alter the thyroid function in individuals with more advanced HIV infection. If thyroid dysfunction is diagnosed in an HIV-infected patient, it should be treated in the usual manner. However, high index of suspicion and caution in the interpretation of thyroid function tests in patients with HIV disease are needed for optimal diagnosis and treatment.