Early assessment of weight velocity can support frontline health workers in predicting malnutrition in HIV-exposed infants: preliminary results from a DREAM cohort in Malawi

BACKGROUND

Children born to HIV-positive mothers are particularly susceptible to malnutrition. Currently, monitoring programs rely on punctual anthropometric measurements to assess child growth. Growth velocities could be an additional tool in identifying critical time windows for prevention and implementation of early intervention for malnutrition.

METHODS

A retrospective analysis was conducted using data from 817 HIV exposed but uninfected children extracted from DREAM program database. By using the WHO reference for growth standards, patterns of weight velocity for different intervals of assessment from one to 18 months of age were explored. Odds ratios and multinomial logistic regressions between selected weight velocity Z-scores thresholds and successive malnutrition indices (at 6, 12, 18 months of age) were calculated.

RESULTS

Weight velocity was above the standard mean in the first 3 months, then progressively declined over time. In children with normal nutritional status, significant risks of becoming malnourished (mild malnutrition - underweight [OR 10.8; 95% CI: 4.5-26], chronic malnutrition - stunting [OR 8.3; 95% CI: 2-34.9] and acute malnutrition - wasting [OR 11.7; 95% CI: 1.5-90.5]) started when weight velocity Z-scores <0, at all interval ages. Multinomial regression showed that in the first 6 months, the weight velocity decrements strongly impacted on underweight (OR 17.9; 95% CI: 4-80.7), while the risk of Stunting occurred later at 18 months (OR 8.7; 95% CI: 4.3-17.6), with highest impact at the lowest thresholds.

CONCLUSIONS

The assessment of weight velocity Z-scores, coupled with the already validated malnutrition indices, can support frontline health workers in early prediction of child malnutrition and performing nutritional counselling in the context of HIV/AIDS and food insecurity.

Who will be lost? Identifying patients at risk of loss to follow-up in Malawi. The DREAM Program Experience

OBJECTIVES

Retention of subjects in HIV treatment programmes is crucial for the success of treatment. We evaluated retention/loss to follow-up (LTFU) in subjects receiving established care in Malawi.

METHODS

Data for HIV-positive patients registered in Drug Resource Enhancement Against AIDS and Malnutrition centres in Malawi prior to 2014 were reviewed. Visits entailing HIV testing/counselling, laboratory evaluations, nutritional evaluation/supplementation, community support, peer education, and antiretroviral (ART) monitoring/pharmacy were noted. LTFU was defined as > 90 days without an encounter. Parameters potentially associated with LTFU were explored, with univariate/multivariate logistic regression analyses being performed.

RESULTS

Fifteen thousand and ninety-nine patients registered before 2014; 202 (1.3%) were lost to follow-up (LTFU) (1.3%). Nine (0.5%) of 1744 paediatric patients were LTFU vs. 1.4% (n = 193) of 13 355 adults (P < 0.001). Subjects who were LTFU had fewer days in care than retained subjects (1338 vs. 1544, respectively; P < 0.001) and a longer duration of ART (1530 vs. 1300 days, respectively; P < 0.001). Subjects who were LTFU had higher baseline HIV viral loads (P = 0.016) and higher body mass indexes (P < 0.001), were more likely to live in urban settings (88% of patients who were LTFU lived in urban settings) with better housing [relative risk (RR) 2.3; 95% confidence interval (CI) 1.67-3.09; P < 0.001], and were more likely to be educated (RR 1.88; 95% CI 1.42-2.50; P < 0.001). Distance to the centre and cost of transportation were associated with LTFU (RR 3.4; 95% CI 2.84-5.37; P < 0.001), as was absence of a maternal figure (RR 1.57; 95% CI 1.17-2.09; P < 0.001). Viral load, distance index, education and a maternal figure were predictive of LTFU.

CONCLUSIONS

Educated, urbanized HIV-infected adults living far from programme centres are at high risk of LTFU, particularly if there is no maternal figure in the household. These variables must be taken into consideration when developing retention strategies.

Reduction of maternal mortality with highly active antiretroviral therapy in a large cohort of HIV-infected pregnant women in Malawi and Mozambique

Background

HIV infection is a major contributor to maternal mortality in resource-limited settings. The Drug Resource Enhancement Against AIDS and Malnutrition Programme has been promoting HAART use during pregnancy and postpartum for Prevention-of-mother-to-child-HIV transmission (PMTCT) irrespective of maternal CD4 cell counts since 2002.

Methods

Records for all HIV+ pregnancies followed in Mozambique and Malawi from 6/2002 to 6/2010 were reviewed. The cohort was comprised by pregnancies where women were referred for PMTCT and started HAART during prenatal care (n = 8172, group 1) and pregnancies where women were referred on established HAART (n = 1978, group 2).

Results

10,150 pregnancies were followed. Median (IQR) baseline values were age 26 years (IQR:23–30), CD4 count 392 cells/mm³ (IQR:258–563), Viral Load log₁₀ 3.9 (IQR:3.2–4.4), BMI 23.4 (IQR:21.5–25.7), Hemoglobin 10.0 (IQR: 9.0–11.0). 101 maternal deaths (0.99%) occurred during pregnancy to 6 weeks postpartum: 87 (1.1%) in group 1 and 14 (0.7%) in group 2. Mortality was 1.3% in women with <than 350 CD4 cells/mm³ and 0.7% in women with greater than 350 CD4s cells/mm³ [OR = 1.9 (CL 1.3–2.9) p = 0.001]. Mortality was higher in patients with shorter antenatal HAART: 22/991 (2.2%) if less than 30 days and 79/9159 (0.9%) if 31 days or greater [OR = 2.6 (CL 1.6–4.2) p<0.001]. By multivariate analysis, shorter antenatal HAART (p<0.001), baseline values for CD4 cell count (p = 0.012), hemoglobin (p = 0.02), and BMI (p<0.001) were associated with mortality. Four years later, survival was 92% for women with shorter antenatal HAART and 98% for women on established therapy prior to pregnancy, p = 0.001.

Conclusions

Antiretrovirals for PMTCT purposes have significant impact on maternal mortality as do CD4 counts and nutritional status. In resource-limited settings, PMTCT programs should provide universal HAART to all HIV+ pregnant women given its impact in prevention of maternal death.

Nutritional rehabilitation of HIV-exposed infants in Malawi: results from the drug resources enhancement against AIDS and malnutrition program

Infant malnutrition in sub-Saharan Africa is a public health priority and a challenge in high HIV prevalence areas. The Drug Resources Enhancement Against AIDS and Malnutrition program, with multiple medical centers in Sub-Saharan Africa, developed an innovative intervention for the surveillance and control of malnutrition. In a pilot initiative, 36 HIV-exposed children were evaluated at baseline upon presentation for malnutrition and at six months post- treatment. Parameters included HIV-free survival, nutritional status and change in diet. Food diary data was entered and processed using the Nutrisurvey (WHO) software. At 6 months post-intervention, a significant improvement in anthropometric parameters was noted. Slowing of linear growth was observed in patients with malaria with a mean gain in centimetres of 4.4 ± 1.7 as compared to 5.6 ± 1.7 in children with no malaria, p < 0.048 (CL 95%: −2.32, −0.01). Dietary diversity scores increased from 5.3 ± 1.9 to 6.5 ± 1.3, p < 0.01 at 6 months. A significant increase (+25%, p < 0.02) in the number of children eating fish meals was noted. Our pilot data describes positive outcomes from a rehabilitative nutritional approach based on use of local foods, peer education, anthropometric and clinical monitoring in areas of high food insecurity. The relationship between malaria and linear growth retardation requires further investigation.

The impact of integrating food supplementation, nutritional education and HAART (Highly Active Antiretroviral Therapy) on the nutritional status of patients living with HIV/AIDS in Mozambique: results from the DREAM Programme

DREAM (Drug Resources Enhancement against AIDS and Malnutrition) is a multiregional health program active in Mozambique since 2002 and provides free of charge an integrating package of care consisting of peer to peer nutritional and health education, food supplementation, voluntary counseling and testing, immunological, virological, clinical assessment and HAART (Highly Active AntiRetroviral Treatment). The main goals of this paper are to describe the state of health and nutrition and the adequacy of the diet of a sample of HIV/AIDS patients in Mozambique on HAART and not. A single-arm retrospective cohort study was conducted. 106 HIV/AIDS adult patients (84 in HAART), all receiving food supplementation and peer-to-peer nutritional education, were randomly recruited in Mozambique in two public health centres where DREAM is running. The programme is characterized by: provision of HAART, clinical and laboratory monitoring, peer to peer health and nutritional education and food supplementation. We measured BMI, haemoglobin, viral load, CD4 count at baseline (T0) and after at least 1 year (T1). Dietary intake was estimated using 24h food recall and dietary diversity was assessed by using the Dietary Diversity Score (DDS) at T1. Overall, the patients'diet appeared to be quite balanced in nutrients. In the cohort not in HAART the mean BMI values showed an increases but not significant (initial value: 21.9 ± 2.9; final value: 22.5 ± 3.3 ) and the mean haemoglobin values (g/dl) showed a significant increases (initial value: 10.5+ 2.1; final value: 11.5 ± 1.7 p< 0.024) . In the cohort in HAART, both the mean of BMI value (initial value: 20.7 ± 3.9; final value: 21.9 ± 3.3 p< 0.001) and of haemoglobin (initial value: 9.9 ± 2.2; final value: 10.8 ± 1.7 p< 0.001) showed a higher significant increase. The increase in BMI was statistically associated with the DDS in HAART patients. In conclusion nutritional status improvement was observed in both cohorts. The improvement in BMI was significant and substantially higher in HAART patients because of the impact of HAART on nutritional status of AIDS patients. Subjects on HAART and with a DDS > 5, showed a substantial BMI gain. This association showed an additional expression of the synergic effect of integrating food supplementation, nutritional education and HAART on the nutritional status of African AIDS patients and also highlights the complementary role of an adequate and diversified diet in persons living with HIV/AIDS in resources limited settings.

Incidence and predictors of death, retention, and switch to second-line regimens in antiretroviral- treated patients in sub-Saharan African Sites with comprehensive monitoring availability

BACKGROUND

Antiretroviral treatment programs in sub-Saharan Africa have high rates of early mortality and loss to follow-up. Switching to second-line regimens is often delayed because of limited access to laboratory monitoring.

METHODS

Retrospective analysis was performed of a cohort of adults who initiated a standard first-line antiretroviral treatment at 5 public sector sites in 3 African countries. Monitoring included routine CD4 cell counts, human immunodeficiency virus RNA measures, and records of whether appointments were kept. Incidence and predictors of death, loss to follow-up, and switch to second-line regimens were analyzed by time-to-event approaches.

RESULTS

A total of 3749 patients were analyzed; at baseline, 37.1% were classified as having World Health Organization disease stage 3 or 4, and the median CD4 cell count was 192 cells/mL. First-line regimens were nevirapine based in 96.5% of patients; 17.7% of patients attended <95% of their drug pickup appointments. During 4545 person-years of follow-up, mortality was 8.6 deaths per 100 person-years and was predicted by lower baseline CD4 cell count, lower hemoglobin level, and lower body mass index (calculated as weight in kilograms divided by the square of height in meters); more-advanced clinical stage of infection; male sex; and more missed drug pickup appointments. Dropouts (which accrued at a rate of 2.1 dropouts per 100 person-years) were predicted by a lower body mass index, more missed visits and missed drug pickup appointments, and later calendar year. Incidence of switches to second-line regimens was 4.9 per 100 person-years; increased hazards were observed with lower CD4 cell count and earlier calendar year at baseline. In patients who switched, virological failure was predicted by combined clinical and CD4 criteria with 74% sensitivity and 30% specificity.

CONCLUSIONS

In an antiretroviral treatment program employing comprehensive monitoring, the probability of switching to second-line therapy was limited. Regular pickup of medication was a predictor of survival and was also strongly predictive of patient retention.

Comparison of HIV type 1 sequences from plasma, cell-free breast milk, and cell-associated breast milk viral populations in treated and untreated women in Mozambique

We analyzed the sequences of the HIV viral populations obtained from plasma, cell-free breast milk, and breast milk cells of HAART-treated (23) and untreated (30) HIV-infected women to obtain information about the origin of the breast milk virus. Sequence analyses of viruses were performed using the TruGene HIV-1 assay. Direct sequences of the reverse transcriptase (RT) and protease (PR) genes were analyzed using the Phylip 3.68 suite of sequence analysis program and pairwise evolutionary distances were calculated with the Kimura two parameter model for estimation of distances. We found that the genetic distances between the plasma and the cell-free breast milk viruses and between the cell-free and cell-associated breast milk viruses for RT were higher in HAART-receiving women than in untreated women, suggesting viral evolution under selective drug pressure in breast milk. Our data support the hypothesis of the presence of an actively replicating viral population in the breast milk compartment, distinct from that present in plasma.

Excessive early mortality in the first year of treatment in HIV type 1-infected patients initiating antiretroviral therapy in resource-limited settings

The response to treatment and risk factors for early mortality following initiation of combination antiretrovirals(ARVs) in a cohort of African patients are described in a retrospective cohort design. Medical history, laboratory parameters, and mortality data were reviewed for patients initiating ARVs in 12 clinical centers in Mozambique, Tanzania, and Malawi. Among 3456 HIV-1-infected patients who received ARVs for more than 6 months, at baseline 72% had WHO clinical stages 3/4, 7% had a viral load 400 copies/ml, and 38% had a CD4 cell count >200/microl. One year later, 78% had undetectable virus loads and 79% had CD4 cell counts >200 cells/mm3. In the first year of HAART 260 deaths occurred (97 per 1000 person/years) with mortality peaking in the first 3 months. The highest mortality was observed in patients with low BMI, low hemoglobin levels, and CD4 values <200 cells/microl at baseline. Mortality rates following initiation of HAART are higher in patients in resource-limited areas, particularly in the first 90 days following treatment initiation.HAART initiated at higher CD4 cell count levels, especially among malnourished and/or anemic patients, will carry significant public health impact.

Seroprevalence of HHV8 in a cohort of HIV-negative and HIV-positive patients in Mozambique

Kaposi Sarcoma shows several different clinical and epidemiological patterns. In Sub-Saharan Africa, where the HIV achieves an high prevalence of infection, the KS can be found both in HIV positive than in HIV negative patients, and the diffusion of the HHV8 virus is endemic. The aim of the work is to evaluate the HHV8 seroprevalence in Mozambique. Moreover the relationship of some main indicators, as CD4 and CD8 cells count, HIV viral load, Body Mass Index and haemoglobin values have been calculated in a part of the DREAM Cohort, (HIV positive patients enrolled in the Community of Sant'Egidio program to fight AIDS in the Sub-Saharan Africa). In the HIV positive cohort HHV8 negative and HHV8 positive groups show statistical significance (p < 0.05) in CD4 cells count, a strong significance (p = 0.01) in CD8 cells count and a significance also in Haemoglobin levels (p = 0.35). The difference in Haemoglobin levels (0.5 g/dl) is related more to a statistical than a clinical significance. The study confirms the free circulation of the HHV8 virus in the Mozambican population, with a prevalence rate of 51.1%, similar than that measured in bordering countries. Considering the CD8 value within the HIV positive sub-cohort a strong correlation with the positivity for HHV8 and the immunological status is suggested.

Triple antiretroviral prophylaxis administered during pregnancy and after delivery significantly reduces breast milk viral load: a study within the Drug Resource Enhancement Against AIDS and Malnutrition Program

BACKGROUND

The administration of antiretroviral therapy to lactating women could represent a possible strategy to reduce postnatal HIV transmission. In this study, we assessed the effect of antiretroviral treatment on breast milk viral load and determined plasma and breast milk drug concentrations in pregnant women receiving highly active antiretroviral therapy (HAART).

METHODS

We studied 40 women receiving zidovudine, lamivudine, and nevirapine from 28 weeks of gestation to 1 month postpartum (group A) and 40 untreated pregnant women (group B). Blood and breast milk samples were collected at delivery and 7 days postpartum.

RESULTS

Women in group A had received a median of 85 days of therapy before delivery. Median breast milk concentrations of nevirapine, lamivudine, and zidovudine were 0.6, 1.8, and 1.1 times, respectively, those in maternal plasma. HIV RNA levels in breast milk were significantly lower in group A than in group B (median of 2.3 vs. 3.4 log at delivery and 1.9 vs. 3.6 log at day 7; P < 0.001 for both comparisons).

CONCLUSIONS

Antiretroviral drugs administered during the last trimester of pregnancy and after delivery reach levels similar to or higher than plasma concentrations in breast milk and can significantly reduce HIV RNA levels. Our data support the potential role of maternal HAART prophylaxis in reducing the risk of breast-feeding-associated transmission.

Pediatric highly active antiretroviral therapy in Mozambique: an integrated model of care

AIM

To test the impact of a public health model to implement HIV pediatric care in Limited Resource Settings.

METHODS

A retrospective study on the clinical files of 679 Mozambican children (mean age 4.4 years; SD 3.2), has been carried out. The pediatric patients received HAART (Highly Active Anti-Retroviral Therapy) in the framework of DREAM, a nationwide public health program offering an integrated model of care to HIV patients including free-of-charge HAART and monitoring, nutritional assessment and supplementation, peer-to-peer education, active tracing of the dropped out patients.

RESULTS

HAART was started in 297 subjects out of 679. The median time of treatment was 286 (IQ 25-75:125-465). Mortality rate was lower in the sub-sample receiving HAART (8.4%; CI 95%: 5.2-11.6 vs 13.1%; CI 95%: 9.7-16.5). After 6 months of treatment the percentage of viral load lower than 400 copies/mL rose from 4.9% to 46.3%. The percentage of patients with less than 15% of CD4 cells out of the total lymphocyte count and the percentage of patients below the 2 z-score decreased from 56.4% and 58.1% to 8.8% and 38.1% respectively.

CONCLUSIONS

Pediatric HAART in limited resource settings often face difficulties to handle complex treatment schemes, but the implemented model seems to be an effective tool to reduce mortality rate in HIV positive pediatric population.

Safety of nevirapine-containing antiretroviral triple therapy regimens to prevent vertical transmission in an African cohort of HIV-1-infected pregnant women

OBJECTIVE

To assess the incidence and consequences of adverse reactions among African HIV-positive pregnant women treated with fixed-dose combinations of a nevirapine-containing antiretroviral (ARV) triple therapy.

METHODS

A retrospective analysis of the clinical files of 703 HIV-1-positive pregnant women treated with a nevirapine-containing regimen between May 2002 and July 2004 was conducted. Selection criteria for inclusion in the analysis were: (a) taking ARV for more than 14 days; (b) baseline values of transaminases below the threshold of 2.5 times the upper limit of normal (ULN). The women were on a nevirapine-containing regimen for a median of 127 days [interquartile range (IQR) 86-190 days], starting on average at the 27th week of gestation (standard deviation+/-9.5) and continuing up to a maximum of 6 months after delivery. All women were offered formula milk to feed the babies. Highly active antiretroviral therapy (HAART) was continued beyond 6 months only if the patient qualified on the first visit. The main outcome measures were incidence of hepatotoxicity, skin rashes and Stevens-Johnson syndrome. Multivariate analysis to assess the impact of several factors on the adverse reaction rate was performed.

RESULTS

As of 1 August 2004, 554 pregnancies reached term, 96 women were still pregnant, and 53 women dropped out of the programme before giving birth. After 2 months of therapy the percentage of patients with a viral load less than 1000 HIV-1 RNA copies/mL increased to 78.6%; average CD4 cell counts increased from 490 cells/microL before therapy to 630 after therapy. The incidence of grade 3-4 adverse reactions (hepatotoxicity, skin rashes and Stevens-Johnson syndrome) was 6.5, 2.4 and 1.1%, respectively. Five women died during pregnancy (0.88%). Only one of the deaths could be associated with ARV treatment.

CONCLUSION

Nevirapine-containing regimens in pregnant woman, at all CD4 cell count levels, appear to be safe in African settings.

Improving adherence to highly active anti-retroviral therapy in Africa: the DREAM programme in Mozambique

Ensuring high levels of adherence to highly active anti-retroviral therapy (HAART) is a priority in treating people living with AIDS. This study reports the rates of adherence of patients served by DREAM (Drug Resource Enhancement against AIDS and Malnutrition) in the city of Matola, Mozambique. DREAM, an innovative programme tailored for Africa, was implemented by the Community of Sant'Egidio in August 2001. DREAM provides patients with anti-retroviral drugs and laboratory tests at no charge, and is based on a particular strategy of health education and organization of services designed for a population that is predominantly poor and has a low level of formal education. This study analyzes the adherence of 154 patients over a period of 6 months. In evaluating adherence, two indicators were used: (1) the percentage of appointments kept for check-ups, tests and the collection of medicine, and (2) the overall change in the patients' blood chemistry over the 6-month period. Of the 154 patients, 127 (82.5%) kept more than 90% of their appointments. Adherence to the programme was further confirmed by a relevant increase of hemoglobin levels and CD4 counts, and a significant decrease in the viral loads among the 154 patients.

Expression and release of LAG-3-encoded protein by human CD4+ T cells are associated with IFN-gamma production

The lymphocyte activation gene (LAG) -3 is a member of the immunoglobulin super-family that is selectively transcribed in human activated T and NK cells. In this work, the possibility that LAG-3 expression by human CD4+ T cells was preferentially related to one or another phenotype of cytokine secretion was investigated. Surface LAG-3 expression correlated with IFN-gamma, but not IL-4, production in antigen-stimulated T cells and it was up-regulated by IL-12. Most activated CD4+ T cell clones with established Th1 or Th0 profiles of cytokine secretion expressed LAG-3 on their surface, whereas the great majority of Th2 clones showed neither surface LAG-3 nor LAG-3 mRNA expression. After activation, the majority of CD4+ T cell clones also released soluble LAG-3-related peptides, and such a release correlated positively with the production of IFN-gamma and inversely with the production of IL-4. Thus, LAG-3 expression by activated CD4+ human T cells appear to be preferentially associated with the differentiation/activation pathway leading to the production of IFN-gamma.

Phosphorylation of the gamma chain of the high affinity receptor for immunoglobulin E by receptor-associated protein kinase C-delta

The gamma chain of the high affinity receptor for immunoglobulin E is a member of the T-cell antigen receptor zeta chain family and a functional subunit common to both T-cell and Fc receptors. Here we report that the gamma chain is phosphorylated on threonine in response to protein kinase C activation. Furthermore, the threonine phosphorylation of the gamma chain correlates with the endocytosis of this receptor. We identified a receptor-associated kinase as the calcium-independent protein kinase C-delta and found that it associates with the carboxyl-terminal cytoplasmic domain of the beta chain. In addition, protein kinase C-delta was the only isozyme capable of phosphorylating the gamma chain in vitro. These findings provide evidence for the functional role of protein kinase C-delta in early signal transduction events in the mast cell and suggest a more general mechanism of activation for receptors that share subunits of the zeta chain family.

A clinicopathologic study of ten patients with recurrent unexplained flushing

We describe the clinicopathologic features of 10 patients with recurrent unexplained flushing. These patients were referred to the National Institutes of Health with a diagnosis of mastocytosis or idiopathic anaphylaxis. Both diagnoses were eliminated after evaluation. Patients reported attacks of flushing lasting 15 minutes to 2 days and associated with such symptoms as anxiety, chest tightness, paresthesia, slurred speech, weakness, and pruritus. Abdominal pain was a constant feature, often associated with cramping and an increase in stool frequency. Attacks witnessed by physicians consisted of an exaggerated blush response of the face and upper part of the chest, and were sometimes associated with tachycardia, mild hypertension, and tachypnea. Hives, angioedema, wheezing, and hypotension were not observed. Routine laboratory studies and 5-hydroxyindoleacetic acid, vanillylmandelic acid, and plasma histamine levels were normal. Plasma histamine levels did not elevate during attacks. When performed, results of bone marrow examinations, skin biopsies, and bone scans were normal. Psychiatric examinations frequently revealed somatization disorders. Patients had often been prescribed a wide variety of medications including antihistamines, nonsteroidal anti-inflammatory drugs, and steroids, with little or no benefit. Despite the benign nature of the clinical and laboratory findings, patients had undergone repeated, often invasive, examinations for several years. Whether such patients have a prominent flush response exaggerated through a somatization disorder or a relatively benign flushing disorder associated with putative mediator release remains to be determined. Recognition of this category of patients with unexplained flushing will avoid subjecting such patients to unwarranted repeated examinations, procedures, and inappropriate therapy.

Specific humoral response to cows' milk proteins and ovalbumin in children with atopic dermatitis

Serum antibodies to four common food antigens, three cows' milk proteins (casein, alpha-lactalbumin and beta-lactoglobulin) and ovalbumin, were investigated in 21 children with atopic dermatitis (aged 3 months to 3 years) and in 15 age-matched healthy controls. Specific IgE was measured by radioallergosorbent test; an ELISA was developed to detect specific IgG, IgG subclasses and IgA. Specific IgE was found in 76% of patients, while antigen-directed IgG and IgA were present both in patients and healthy controls; IgG to ovalbumin and IgA to alpha-lactalbumin were significantly higher in children with atopic dermatitis. The analysis of the IgG subclass distribution showed different patterns of response, IgG1 and IgG4 being higher in patients (even though statistically significant only for ovalbumin), and IgG2 and IgG3 being lower in this group. The presence of food-specific IgE in the majority of atopic children and the different specific IgG subclass patterns observed in patients and controls may reflect an alteration in the immune response to dietary proteins in atopic dermatitis.

RAST-detection of specific IgE in diphenylmethane diisocyanate exposed workers: considerations in performance of the test

Some parameters which might affect RAST results, i.e. incubation length, degree of ligand substitution, and total IgE levels, were examined in a RAST system employing diphenylmethane diisocyanate--human serum albumin (MDI-HSA) conjugates as antigens, both in exposed symptomatic and in non-exposed subjects. The reaction equilibrium was reached after 9 and 18 h. respectively, in the first and the second step of the test. A marked correlation with the degree of ligand substitution was observed, the highest sensitivity being achieved with the lowest (2.9) MDI/HSA molar ratio examined. Higher (up to 50) degrees of substitution resulted in progressively lower levels of radioactivity bound and in a loss of specificity, as confirmed by RAST inhibition experiments. At high levels of ligand substitution, high titers of total serum IgE affected RAST results.

Nuclear architecture, intranuclear DNA distribution, and nuclease digestion

G0, G1, and mammalian cells and nuclei were shortly digested with either micrococcal nuclease or DNAse I, both before and after mild fixation, either before (G0) or after (G1) partial hepatectomy. Cells were Feulgen stained and examined by high resolution light microscopy. In metabolically active G1 nuclei, intranuclear DNA appears organized at least in two distinct domains, whereby the highly dispersed one is large enough to be detected at the resolution of the light microscope and appears preferentially attacked by limited DNAse I digestion. The action of the enzyme is readily apparent only in the nuclei that are first digested and then fixed. Spectroscopic characterization of the same nuclei reveals that the fixation causes a sizeable removal of proteins, mostly in the soluble chromatin subfraction. Results are discussed in terms of two control levels for gene expression and for higher order DNA structure.