Logistical constraints associated with the collection and analysis of biological samples in community-based settings have been a significant impediment to integrative, multilevel biodemographic and biobehavioral research. However, recent methodological developments have overcome many of these constraints and have also expanded the options for incorporating biomarkers into population-based health research in international as well as domestic contexts. In particular, using dried blood spot (DBS) samples—drops of whole blood collected on filter paper from a simple finger prick— provides a minimally invasive method for collecting blood samples in nonclinical settings. After a brief discussion of biomarkers more generally, we review procedures for collecting, handling, and analyzing DBS samples. Advantages of using DBS samples—compared with venipuncture—include the relative ease and low cost of sample collection, transport, and storage. Disadvantages include requirements for assay development and validation as well as the relatively small volumes of sample. We present the results of a comprehensive literature review of published protocols for analysis of DBS samples, and we provide more detailed analysis of protocols for 45 analytes likely to be of particular relevance to population-level health research. Our objective is to provide investigators with the information they need to make informed decisions regarding the appropriateness of blood spot methods for their research interests.

/pdf/what-a-drop-can-do-dried-blood-spots-as-a-minimally-invasive-55dugnpeu0.pdf

What a Drop Can Do: Dried Blood Spots as a Minimally Invasive Method for Integrating Biomarkers Into Population-Based Research

To evaluate the relationship between the clinical presentation of tuberculosis and the CD4 cell count in patients with human immunodeficiency virus (HIV) infection, we evaluated clinical and laboratory features of 97 HIV-infected patients with tuberculosis in whom CD4 cell counts were available. Extrapulmonary tuberculosis was found in 30 (70%) of 43 patients with 300 CD4 cells/microL (p = 0.02). Mycobacteremia was found in 18 (49%) of 37 patients with 300 CD4 cells/microL (p = 0.002). Acid-fast smears were more often positive in patients with low CD4 cell counts. Positive tuberculin skin tests were more common in patients with high CD4 counts. On chest roentgenograms, mediastinal adenopathy was noted in 20 (34%) of 58 patients with 200 CD4 cells/microL (p = 0.04). Pleural effusions were noted in six (10%) of 58 patients with 200 CD4 cells/microL (p = 0.04). The CD8 cell counts did not correlate with the manifestations of tuberculosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship of the Manifestations of Tuberculosis to CD4 Cell Counts in Patients with Human Immunodeficiency Virus Infection

Series editors J M Stephenson, A Babiker

The study of sexual behaviour lies at the heart of understanding the transmission dynamics of sexually transmitted infections (STIs). Academic investigation into sexual behaviour dates back to the 18th century and, over time, has employed a variety of approaches including the medical and psychiatric investigation of sexual disorders, anthropological investigations, and survey research based largely on volunteer samples. More recent studies, driven largely by the public health response to HIV/AIDS, have focused on large scale probability sample survey research.1–5 Key areas of inquiry have shifted towards describing population patterns of risk behaviours for STI/HIV transmission, understanding how epidemics of STIs are generated, and informing disease control strategies.

Sexual behaviour is a largely private activity, subject to varying degrees of social, cultural, religious, moral and legal norms and constraints. A key challenge for all sex survey research is to generate unbiased and precise measures of individual and population behaviour patterns. Methods are needed to minimise measurement error which may be introduced by participation bias, recall and comprehension problems, and respondents' willingness to report sensitive and sometimes socially censured attitudes or behaviours.6, 7 This paper briefly considers the role of different types of study in understanding STI epidemiology. It then focuses on potential sources of measurement error in survey research and strategies for assessing and limiting them.Sex Transm Inf 2001;77:84–92

The type of study chosen will depend on the purpose of the investigation. However, studies generally fall into four main groups: general population surveys, studies on population subgroups, partner and network studies, ethnographic and qualitative studies.

### GENERAL POPULATION PROBABILITY SAMPLE SURVEYS

Cross sectional population surveys aim to describe the overall distribution of behaviours in populations. By using probability sampling techniques and maximising response rates, large scale behavioural surveys can provide robust estimates of the prevalence …

https://sti.bmj.com/content/sextrans/77/2/84.full.pdf

Measuring sexual behaviour: methodological challenges in survey research

γδ T cells, αβ T cells, and B cells are present together in all but the most primitive vertebrates, suggesting that each population contributes to host immune competence uniquely and that all three are necessary for maintaining immune competence. Functional and molecular analyses indicate that in infections, γδ T cells respond earlier than αβ T cells do and that they emerge late after pathogen numbers start to decline. Thus, these cells may be involved in both establishing and regulating the inflammatory response. Moreover, γδ T cells and αβ T cells are clearly distinct in their antigen recognition and activation requirements as well as in the development of their antigen-specific repertoire and effector function. These aspects allow γδ T cells to occupy unique temporal and functional niches in host immune defense. We review these and other advances in γδ T cell biology in the context of their being the major initial IL-17 producers in acute infection.

γδ T cells: first line of defense and beyond.

MICA Engagement by Human Vγ2Vδ2 T Cells Enhances Their Antigen-Dependent Effector Function

Increased proportions of the small lymphoid subset expressing T cell receptor (TCR) gamma delta occur in different infectious diseases, particularly in mycobacterial infections. In this study the two main subsets of TCR gamma delta+ cells in peripheral blood mononuclear cells (PBMC) of 54 patients with human immunodeficiency virus type 1 infection were analyzed. These subsets were defined by indirect immunofluorescence techniques and FACS analysis using BB3 and A13 monoclonal antibodies, which specifically react with V delta 2- and V delta 1-encoded forms of TCR gamma delta. The proportion of BB3+(V delta 2+) and A13+(V delta 1+) cells was analyzed in purified PBMC populations. Patients were stratified according to Walter Reed (WR) clinical stage. A sharp increase in percentage of A13+(V delta 1+) cells was observed in all stages of the disease. In addition, a strict correlation was found with stage of the disease and percentage of CD8+ PBMC. An inverse correlation was found with the proportion of CD4+ PBMC. An early (WR2) inversion of the V delta 2-to-V delta 1 ratio was consistently detected even before the inversion of the CD4-to-CD8 ratio.

Selective Increase of a Subset of T Cell Receptor γδ T Lymphocytes in the Peripheral Blood of Patients with Human Immunodeficiency Virus Type 1 Infection

The persistence of immunoglobulin M (IgM) antibody to Toxoplasma gondii in sera from 38 patients after toxoplasmic lymphadenopathy was investigated by using an indirect immunofluorescence assay, a double-sandwich enzyme-linked immunosorbent assay, and an immunosorbent agglutination assay. Positive predictive values at 3 and 6 months after lymphadenopathy were, respectively, 45 and 73% for the indirect immunofluorescence assay, 25 and 45% for the double-sandwich enzyme-linked immunosorbent assay, and 22 and 43% for the immunosorbent agglutination assay.

https://jcm.asm.org/content/jcm/27/9/2133.full.pdf

Significance of specific immunoglobulin M in the chronological diagnosis of 38 cases of toxoplasmic lymphadenopathy.

Fluconazole, a new triazole derivative, was evaluated in a pilot study of 34 episodes of candidiasis in 24 children. All the patients had predisposing conditions, such as human immunodeficiency virus infection, cancer, organ or bone marrow transplantation, neonatal age and malnutrition, and obstructive uropathy. The drug was administered at 6 mg/kg (body weight) once daily either orally or intravenously. Two patients with fungemia due to Candida parapsilosis required an increased dosage of 12 mg/kg. Clinical and microbiological success was achieved in 30 of 34 cases (88%). Drug-related transaminase increases were observed in two cases (6%). Fluconazole may represent an effective alternative to amphotericin B in the treatment of candidiasis in children. Comparative trials are necessary to assess optimal dosages and efficacy.

Fluconazole in the treatment of candidiasis in immunocompromised children.

Twenty-four consecutive HIV-positive patients affected byToxoplasma gondii encephalitis received trimethoprim-sulfamethoxazole (cotrimoxazole) as acute-phase treatment. Two dosage regimens of cotrimoxazole were used: 40 mg/kg/day (12 patients) or 120 mg/kg/day (12 patients) of total compound (trimethoprim plus sulfamethoxazole). Clinical and radiological responses to treatment were evaluated, and the product-limit method for survival data analysis was used. Eighteen of 24 patients showed both a clinical and radiological response (75 % response rate). There were no differences in response rates between patients receiving the two dosage regimens of cotrimoxazole. Adverse reaction consisted of leukopenia (two cases) and skin rash (three cases) which led to the discontinuation of the drug in one case. These results suggest that a randomized, controlled clinical trial should be carried out comparing cotrimoxazole versus sulfadiazine-pyrimethamine in AIDS patients withToxoplasma gondii encephalitis.

Cotrimoxazole therapy of Toxoplasma gondii encephalitis in AIDS patients.

The Walter Reed staging classification in the follow-up of HIV infection.

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