No strong long-term effect of vitamin A supplementation in infancy on CD4 and CD8 T-cell subsets. A community study from Guinea-Bissau, West Africa.

The World Health Organization recommends that 100,000 IU of vitamin A be given to infants between 6 and 12 months of age at the same time as measles vaccination in order to prevent vitamin A deficiency. In the present study, our aim was to assess the effect of vitamin A supplementation on T-cell subsets in a randomized factorial design, seeking a possible modifying effect of measles vaccination. Three hundred children were allocated either to two doses of measles vaccine at 6 and 9 months of age or to poliomyelitis vaccine at age 6 months and measles vaccine at age 9 months. Within each group, infants were to receive two doses of vitamin A or two doses of placebo at 6 and 9 months of age. We found no significant effect of vitamin A supplementation on CD4 and CD8 T-cell subsets at 3 and 9 months after supplementation. We found no effect of measles vaccine and no interaction between vitamin A supplementation and measles vaccine. Based on these observations, vitamin A supplementation does not seem to have a strong long-term effect on CD4 and CD8 T-cell subsets in infants without clinical vitamin A deficiency.

Increased prevalence of retrovirus infections among older women in Africa.

Recent studies of HIV-2 have suggested an increased incidence and prevalence among women older than 45 y compared with younger women. We therefore examined whether this phenomenon applied generally to all 3 major retroviruses, HIV-1, HIV-2 and HTLV-I, among women in Africa. We conducted a MedLine search from 1987 to 1997, using the keywords Africa and HIV-1, HIV-2 or HTLV, respectively. Community studies, national surveys and studies on professional cohorts were selected. Age groups > 45/50 y were compared with the age group with the lowest female/male prevalence ratio between 20 and 44 y of age. Thirty-one studies had sufficient data to be included. The female/male odds ratio (OR) for seropositivity was calculated for the old and the young age groups, respectively, providing the ratio of odds ratios: OR (old)/OR (young). Summary ratios for studies of all 3 retroviruses were estimated. In general we found a higher female/male prevalence ratio in the age group over 45/50 y than in the younger age group. For HIV-1 the odds ratio was 1.82 times [95% confidence interval (CI) 1.19-2.79] higher in the old age group than in the young group. For HIV-2 it was 1.97 [95% CI 0.95-4.08], and for HTLV-I it was 2.02 [95% CI 0.99-4.14] times higher. For all 3 viruses combined, the ratio was 1.88 [95% CI 1.36-2.61]. The few incidence studies of HIV-1 and HIV-2 indicated a similar tendency. Since differential mortality is unlikely to explain the pattern, the increase in the HIV-1, HIV-2 and HTLV-I female/male prevalence ratio suggests that older women may have increased exposure or susceptibility to all 3 retrovirus infections.

Evaluation of T cell subsets by an immunocytochemical method compared to flow cytometry in four countries.

The authors tested an alternative method for CD4 and CD8 T lymphocytes enumeration, the immunoalkaline phosphatase method (IA), in three African countries and in Denmark. The IA determinations from 136 HIV antibody positive and 105 HIV antibody negative individuals were compared to the corresponding results obtained by flow cytometry (FC) performed in the respective countries. The authors found good correspondence between the two methods for measurements of CD4 and CD8 T lymphocytes independent of serological status and geographical site. However, the CD4 and CD8 T lymphocytes values obtained by the two methods are not interchangeable as IA compared to FC consistently gives higher percentage of CD4 T lymphocytes, and lower percentage of CD8 T lymphocytes. Mean differences between the two methods did not differ between the three African countries indicating that the IA method provides systematic results. Replicate measurements suggested good correspondence between results obtained by IA. By using an IA level of < 300 CD4 T lymphocytes/microliter, the sensitivity was 81% and specificity 96% for detecting an FC level of < 200 CD4 T lymphocytes/microliter. Using an IA level of < 20% CD4 T lymphocytes, the sensitivity was 89% and specificity 95% for detecting an FC level of < 14% CD4 T lymphocytes. The FC and IA methods had the same internal correspondence between low absolute CD4 T cell count and low CD4 percentages; the sensitivity and specificity for detecting a low absolute CD4 T cell counts with a low CD4 percentage was 92% and 68% for FC and 91% and 73% for IA, respectively. The IA method is 10-fold cheaper than FC, is independent of advanced laboratory facilities, and does not need immediate processing of samples as blood smears can be stored for long periods. The IA method is therefore suitable for use in areas with limited resources and laboratory facilities where there is a need for immunological surveillance in hospital or community studies.

9-year HIV-2-associated mortality in an urban community in Bissau, west Africa.

BACKGROUND: Community studies with 1-3 years of follow-up have reported four to five times higher mortality in HIV-2-infected than in uninfected adults. In a cohort study of HIV-1, an increasing difference in mortality rates of HIV-1-infected and uninfected individuals is expected over time, because of rising mortality with advancing HIV-1 infection. We therefore investigated long-term survival of HIV-2-infected adults. METHODS: Adults enrolled in 1987 in a community study of HIV-2 infection in Guinea-Bissau were followed up with serological surveys in 1989 and 1992. Survival was assessed in 1995, 9 years after enrollment. FINDINGS: The annual incidence of HIV-2 was 0.7% for adults and tended to be higher for older individuals than for participants aged 15-44 years (relative risk 3.21 [95% CI 0.91-11.37]). With control for age, HIV-2-infected adults had twice as high mortality as uninfected individuals (mortality ratio 2.32 [1.18-4.57]); the mortality ratio was highest in the first year of the study (4.50 [1.31-15.43]). The difference between infected and uninfected individuals was stronger for adults under 45 years of age (mortality ratio 4.72 [1.86-11.97]) than for older people (1.35 [0.51-3.56]). HIV-2-infected individuals living with an infected spouse had significantly higher mortality than HIV-2-infected individuals living with an uninfected spouse (p = 0.027). INTERPRETATION: HIV-2-associated mortality is not increasing with length of follow-up. Mortality in HIV-2-infected adults is only twice as high as that in uninfected individuals. In the majority of adults, HIV-2 has no effect on survival.

PIP: While HIV-2 infection can lead to AIDS, it takes longer than HIV-1 to induce immunosuppression and AIDS, it is less transmissible, and it is associated with lower mortality than HIV-1 infection. 1329 people from among 100 houses in Guinea-Bissau participated in a 1987 study of HIV seroprevalence in their community. 8.9% of the family members older than age 14 years were infected with HIV-2, as well as 0.6% of the 677 children, but no one was infected with HIV-1. All subjects enrolled in the 1987 study over age 14 were followed up with serological surveys in 1989 and 1992, with their survival assessed in 1995. HIV-2 associated mortality did not increase over time and mortality in HIV-2-infected adults was only twice as high as that among uninfected individuals. In the majority of adults, HIV-2 has no effect upon survival. The difference in mortality between the infected and the uninfected was greater for adults under age 45 years than for older people. Furthermore, HIV-2-infected individuals living with an infected spouse had significantly higher mortality than those living with an uninfected spouse.

T-lymphocyte subsets in West African children: impact of age, sex, and season.

OBJECTIVE: There has been no reference material for T-lymphocyte subsets for normal children in developing countries. We therefore used T-lymphocyte subset determinations among children in three different studies in Guinea-Bissau to construct age-related reference material and to examine possible determinants of T-lymphocyte subset levels. METHODS: A total of 803 healthy West African children younger than 6 years were included in the three community studies of T-lymphocyte subsets among twins and singletons, after measles infection and after measles immunization. We used the immunoalkaline phosphatase method to determine T-lymphocyte subsets. RESULTS: We found differences by age, sex, and season, whereas there were no significant differences by birth order, twinning, or ethnic group. The CD4+ percentage declined from birth to age 2 years, at which time it started to increase to higher levels at age 4 to 5 years. The CD8+ percentage increased gradually from early infancy to age 2 to 4 years. The leukocyte count peaked at age 12 to 23 months and declined thereafter, whereas the lymphocyte percentage peaked at age 1 to 5 months and declined gradually thereafter. Compared with dry-season results, the lymphocyte percentage, the absolute lymphocyte count, the absolute CD4+ T-lymphocyte count, and the CD4+/CD8+ ratio were significantly lower during the rainy season, whereas the CD8+ percentage was increased during the rainy season. Girls had higher CD4+/CD8+ ratios and lower CD8+ percentages than did boys. CONCLUSIONS: Compared with the limited data on T-lymphocyte subsets available from healthy children in developed countries, Guinean children have markedly lower CD4+ percentages and CD4+/CD8+ ratios and higher lymphocyte percentages during the first 2 years of life, when the pressure of infections is particularly high in Africa.

Sonographic measurement of thymic size in healthy neonates. Relation to clinical variables.

PURPOSE: To assess the variation in thymic size in healthy neonates by sonography and to study the possible correlation to clinical variables. MATERIAL AND METHODS: A study was made of 149 healthy term infants, at less than one week of age. The size of the thymus was assessed by sonography as a volume estimate, the thymic index. This index was compared to sex, weight, length, gestational age, and level of perinatal asphyxia of the infant. T-cell subsets (percentages of CD4 and CD8 receptor-positive T-lymphocytes in peripheral blood) were determined in 83 of the infants and compared to the sonographic thymic index. RESULTS: The thymic index varied between 4 and 29, and was positively correlated to the weight of the infant (p = 0.0003). There was no correlation to sex, length, gestational age or slight perinatal asphyxia. We found no correlation between the size of the thymus and the CD4 percentage, the CD8 percentage, or the CD4/CD8 ratio. CONCLUSION: The size of the thymus in healthy neonates as measured by sonography is significantly correlated to the weight of the infant. For a given weight of an infant it is possible to predict the normal range of thymic size.

Serial CD4 and CD8 T-lymphocyte counts and associated mortality in an HIV-2-infected population in Guinea-Bissau.

In an urban community in Guinea-Bissau, we followed a cohort of human immunodeficiency virus type 2 (HIV-2) seropositive individuals (N = 47) and seronegative controls (N = 82). T-lymphocyte subset determinations were done in 1988, 1990, and 1992. Serial determinations of CD4 percentages, CD8 percentages, and CD4/CD8 ratios for the same individual were stable for 31 seropositive and 51 seronegative individuals with repeated measurements. We found no significant differences in the changes during a 2- or 4-year period in CD4 percentages, CD8 percentages, absolute CD8 T-lymphocyte counts, CD4/CD8 ratio, white blood cell counts, lymphocyte percentages, and absolute lymphocyte counts for HIV-2-seropositive compared with HIV-2-seronegative individuals. Only absolute CD4 T-lymphocyte counts changed more for the HIV-2-seropositive than for HIV-2-seronegative individuals (p = 0.037). HIV-2-infected individuals who lived with an HIV-2-infected spouse had a lower CD4/CD8 ratio and had higher mortality than HIV-2 infected individuals who lived with an uninfected spouse. However, there were no significant differences in immunological and hematological values for the 8 HIV-2 seropositive individuals who died and the 39 who survived in the 8-year follow-up period. In conclusion, progression of immunosuppression in HIV-2 infection seems to be slower than in HIV-1 infection and may not be inevitable in all individuals.

T-lymphocyte subsets and prolonged diarrhea in young children from Guinea-Bissau.

In a community-based prospective study of 380 children conducted between 1987 and 1990, the rate of diarrhea was significantly associated with percentage of CD8 T-lymphocytes and the CD4:CD8 ratio. After adjustment for age and previous diarrhea, the relative incidence of diarrhea with a duration of > or = 7 days was 2.10 (95% confidence interval (CI) 1.15-3.85) in children with 20-29.9% CD8 T-cells and 3.41 (95% CI 1.29-9.01) in children with > or = 30% CD8 T-cells (in comparison with children who had less than 20% CD8 cells) (p for trend = 0.004). There was a nonsignificant tendency for rates of diarrhea of > or = 7 days to decrease according to increasing proportions of CD4 cells (p = 0.194). The authors found no significant association between T-cell subsets and diarrhea which resolved within 6 days. The association between the incidence of prolonged diarrhea and T-cell subset proportions could not be explained as a confounding effect of low weight, breastfeeding, or previous infection with measles or Cryptosporidium. However, other prior infections or micronutrient deficiencies may explain the findings, and these host factors may be significant targets in intervention against diarrheal diseases.

No persistent T lymphocyte immunosuppression or increased mortality after measles infection: a community study from Guinea-Bissau.

BACKGROUND: Because measles immunization is reducing overall childhood mortality in addition to mortality from acute measles infection, it has been suggested that postmeasles cases have excess mortality, possibly related to persistent immunosuppression after measles infection. After an epidemic in 1988 in Guinea-Bissau, we therefore examined T lymphocyte subsets and long term survival among measles cases and controls. METHODS: We examined 69 children < 3 years of age with a median delay of 2 months after measles infection and 71 controls who did not contract measles. The immunoalkaline method was used to determine T lymphocyte subsets. The children were followed for 5 years. RESULTS: Compared with controls, there were no significant differences in white blood cell count, absolute lymphocyte count, CD4 percentage, CD8 percentage, total CD4 count and total CD8 count, although measles cases examined > 2 months after infection had slightly higher CD4 counts than controls (P = 0.06). Adjusted for age, sex and immunization status, postmeasles cases had a mortality rate ratio of 0.50 (95% confidence interval, 0.22 to 1.16) (P = 0.11) compared with controls. CONCLUSIONS: There is no indication of persistent suppression of T cell subsets after measles infection, and postmeasles cases did not have higher mortality than uninfected community controls.

Determination of CD4+ and CD8+ lymphocytes with the cytosphere assay: a comparative study with flow cytometry and the immunoalkaline phosphatase method.

The proportion and absolute numbers of CD4+ and CD8+ lymphocytes in peripheral blood were determined using a new manual method, the cytosphere assay (CA). This method uses small latex beads coated with monoclonal antibodies directed against the CD4 and CD8 receptors, respectively. The CA was compared with two other methods for determination of T lymphocyte subsets, flow cytometry (FC) and the immunoalkaline phosphatase (IA) method, by testing HIV-seropositive and HIV-seronegative samples from Denmark (44) and Ivory Coast (79). For HIV-seropositive samples, both the proportion and the absolute number of CD4+ lymphocytes determined by CA showed a good correlation with results obtained by FC (correlation coefficients were 0.92 and 0.74 in Denmark and The Ivory Coast, respectively) and IA (correlation coefficients were 0.94 and 0.66 in Denmark and The Ivory Coast, respectively). However, for HIV-seronegative samples the corresponding correlation coefficients were low. CD4% determinations deviated more from FC counts at higher CD4 counts than at lower levels for both seronegative and seropositive individuals. In conclusion, the CA performed best for samples from HIV-infected individuals. Before a more general utilization of the method, it is necessary to improve its repeatability and standardize its performance at all levels of CD4+ T cells.

A community study of T lymphocyte subsets and malaria parasitaemia.

In a community survey of 312 children aged 3-6 years in urban Guinea-Bissau, we examined Plasmodium falciparum parasitaemia and T cell subsets. 183 children (59%) had parasites in their blood, 13 had fever > or = 37.5 degrees C, and 9 (3%) had fever and a parasite density > 5000/microL (clinical malaria). Compared with children with no parasitaemia or asymptomatic parasitaemia, children with acute malaria had lymphopenia and significantly lower total CD4 and CD8 cell counts, but there was no significant difference in white blood cell count percentages of CD4 and CD8 cells, or the CD4/CD8 ratio. Children with parasitaemia but without fever had a significantly lower percentage of CD4 cells than children without parasites (P = 0.031), but did not differ in any other haematological index. Controlling for other factors, the CD4 cell percentage was inversely correlated with the density of malaria parasites (P = 0.024), whereas there was no association with CD8 cell percentage or the CD4/CD8 ratio. Asymptomatic parasitaemia may be an important confounder in general community studies of T cell subsets in the tropics.

[Needles for bone marrow examination]. / Kanyler til knoglemarvsundersøgelse.

Over the past decades, numerous new bone biopsy needles have been introduced. Pathological investigation requires sufficiently large and well-preserved specimens. This article reviews the literature concerning the quality of the instruments. Comparison of the various types of needles in controlled studies is not available. Bone-marrow biopsy is discussed in the context of obtaining optimal specimens and choice of biopsy needle.

Severe cryptosporidiosis in children with normal T-cell subsets.

Though Cryptosporidium spp. is considered to cause only a self-limiting illness in immunocompetent children, data from Guinea Bissau suggest that cryptosporidiosis may be a significant cause of deaths in developing countries. An impaired cellular immune function could explain the severe course of cryptosporidiosis in these children. We therefore investigated in a community study whether pre-infectious CD4/CD8 status had an impact on incidence and severity of cryptosporidiosis. Of 168 children below two years of age 21 experienced Cryptosporidium-infection within 156 days after blood sampling, but no tendencies of pre-infectious impaired cellular immune function was found in the cases compared with controls, nor did nine children who acquired persistent diarrhoea or three who died have impaired CD4/CD8 status.

Long-term survival in trial of medium-titre Edmonston-Zagreb measles vaccine in Guinea-Bissau: five-year follow-up.

A trial of protective efficacy which compared medium-titre Edmonston-Zagreb (EZ) measles vaccine (10(4.6) p.f.u.) from the age of 4 months with the standard Schwarz (SW) measles vaccine given from the age of 9 months was started in an urban community in Guinea-Bissau in 1985. Because trials of high-titre measles vaccine have found increased mortality among female recipients, we examined whether EZ medium-titre vaccine was associated with any long-term impact on mortality, suppression of T-cells, or growth. The mortality rate ratio over 5 years of follow-up was 1.12 for EZ children compared with children in the standard group (P = 0.63). Seventy-five percent of the children still residing in the area at 5 years of age took part in an immunological and anthropometric examination. There was no difference in T-cell subsets between the two groups. There was no difference in mid-upper-arm circumference, but EZ children were significantly shorter than the children in the standard group. In conclusion, medium-titre EZ was not associated with reduced survival or persistent immunosuppression.

Long term impact of high titer Edmonston-Zagreb measles vaccine on T lymphocyte subsets.

Several trials of high titer measles vaccine (> 10(4.7) plaque-forming unit) have found female recipients of Edmonston-Zagreb (EZ) vaccine to have lower survival than female recipients of standard measles vaccine. Two trials with medium and high titer EZ vaccine from the age of 4 months were conducted in Guinea-Bissau. To test for possible long term impact on the immune system, an investigation of T cell subsets was conducted among all children still residing in the community at 3 to 5 years of age. No differences were found between recipients of medium titer vaccine and controls. In the second trial, however, recipients of high titer had lower CD4:CD8 ratios than controls and had significantly higher CD8 percentages and lower CD4:CD8 ratios than recipients of medium titer EZ. When analyzed by sex, differences were found only among the girls. However, these differences were small and seemed unlikely to explain the reduced survival which has been associated with high titer EZ measles vaccination. In the 2 years after the investigation of T cell subsets, there was no increased mortality for recipients of EZ vaccine. Hence it is unlikely that high titer vaccine has an persistent adverse effect on survival after 3 years of age.

Long-term survival after Edmonston-Zagreb measles vaccination in Guinea-Bissau: increased female mortality rate.

In an urban area of Guinea-Bissau, 384 children were enrolled in a randomized trial comparing morbidity and mortality rates after receiving high-titer Edmonston-Zagreb (EZ) measles vaccine administered from 4 months of age, with a control group receiving inactivated poliomyelitis vaccine at 4 months of age and the standard Schwarz vaccine from 9 months of age. Children were followed to the age of at least 3 years. The mortality ratio of the EZ vaccinees compared with control subjects was 1.79 (range, 1.06 to 3.02; p = 0.027) if children were excluded at the time of migration; if deaths after migration were included, the mortality ratio was 1.53 (range, 0.94 to 2.49; p = 0.087). Girls in the EZ group had significantly higher mortality rates than girls in the control group (mortality ratio = 1.95; range, 1.07 to 3.56; p = 0.027); there was no difference for the boys (mortality ratio = 0.98; range, 0.41 to 2.30). Adjustment for background factors in a Cox regression model did not modify these estimates. Furthermore, female recipients of EZ vaccine had more days with diarrhea (relative risk = 1.35; range, 1.17 to 1.56; p = 0.00003) and were more likely than control subjects to visit a health center in the month after vaccination (relative risk = 1.86; range, 1.05 to 3.31; p = 0.027); those who consulted were more likely to die subsequently (mortality ratio = 2.31; range, 0.99 to 5.41; p = 0.054). These observations were unplanned and require confirmation in larger studies.

Lack of evidence of vertical transmission of human immunodeficiency virus type 2 in a sample of the general population in Bissau.

Twenty-nine human immunodeficiency virus type 2 (HIV-2) seropositive women identified in a cross-sectional study in Bissau in 1987 participated in a follow-up study in 1988, where each was matched for age and marital status with two HIV-2 seronegative women. Detailed information about all pregnancies was obtained. The HIV-2 seropositive women and their controls had similar mean numbers of pregnancies, live children, children who died, and abortions. The HIV-2 seropositive women did not have a greater risk of having had an abortion or a child who died than did the HIV-2 seronegative women. No difference in survival was seen between children born to HIV-2 seropositive and HIV-2 seronegative women. The H/S-ratios and CD4 numbers were lower in the seropositive group, but none had values lower than 0.4 and 0.4 x 10(9)/L, respectively. Seven prospectively observed children born to HIV-2 seropositive mothers showed no sign of infection. The lack of evidence of transmission of HIV-2 from mother to child is suggested to be due to the absence of marked immunodeficiency in this random sample of the general population.

Cellular profiles in bronchoalveolar lavage fluid of HIV-infected patients with pulmonary symptoms: relation to diagnosis and prognosis.

Bronchoalveolar lavage (BAL) cell differentials and T-lymphocyte subpopulations were analysed in 95 HIV-infected patients with pulmonary symptoms to determine whether the type of cellular inflammatory response could be useful in diagnosis or as a prognostic marker. Patients with Pneumocystis carinii pneumonia (PCP) had more BAL fluid lymphocytes, mainly comprising CD8+ cells, and patients with bacterial infection had more neutrophils than other patients. Neither of these changes were mirrored in peripheral blood. Seven patients who died after their acute episode of PCP had significantly higher BAL fluid neutrophils than 53 patients with PCP who survived (P = 0.002). There seems to be correlation between BAL fluid neutrophilia, PCP and concomitant bacterial infection since four out of seven patients with a fatal outcome had coinfection with bacteria, whereas only one patient with PCP and bacterial coinfection survived (P = 0.0007).

Immunodeficiency in HIV-2 infection: a community study from Guinea-Bissau.

In a community study in Guinea-Bissau, West Africa, 47 HIV-2-seropositive cases and 87 matched controls were evaluated immunologically using immuno-alkaline phosphatase linked to avidin-biotin complex for the assessment of CD4 and CD8 status. HIV-2-seropositive individuals had significantly lower total numbers of CD4 cells and CD4/CD8 ratios, 38% having a total number of CD4 cells less than or equal to 0.5 x 10(9)/l and 36% having a CD4/CD8 ratio less than or equal to 0.8. Total numbers of CD4 cells less than or equal to 0.5 x 10(9)/l or CD4/CD8 ratio less than or equal to 0.8 were found in 53% of the HIV-2 seropositives compared with 11% among controls [odds ratio (OR) = 7.3; 95% confidence interval (CI): 3.1-17.1]. Lymphadenopathy was significantly more frequent among HIV-2 seropositives than among controls (OR = 3.4; 95% Cl: 1.5-7.6). HIV-2 seropositives with lymphadenopathy had significantly fewer lymphocytes (P = 0.008) and lower total CD4 (P = 0.029) and total CD8 number (P = 0.011) than HIV-2 seropositives without lymphadenopathy. This study indicates that HIV-2 has a significant immunosuppressive effect.