Age-related pattern of immunoglobulins G, A and M in children born to HIV-seropositive women

Persistent anti-gag, -Nef, and -Rev IgM levels as markers of the impaired functions of CD4+ T-helper lymphocytes during SIVmac251 infection of cynomolgus macaques

This study analyzed the antigen-specific (Gag, Nef, Rev, and Tat) IgM, IgG, and IgA humoral responses during the first 200 days of SIVmac251 infection in cynomolgus macaques. These responses were tested for correlation with the CD4(+) T-cell-related hematologic parameters and viral load throughout the course of the study (acute and chronic infection, during and after antiretroviral therapy). Strong inverse correlations were observed between the percentage of CD4(+) T cells at almost every timepoint of the study and the levels of IgM (but not IgG and IgA) against Gag, Nef, and Rev (but not Tat) measured after, but not during, the primary peak of IgM response. Significant levels of persistent antigen-specific IgMs may reflect the prevalence of mature plasma cells that have not undergone immunoglobulin class switching, possibly due to defects in helper T-cell function. Strong correlations were observed between the preinfection CD4(+) T-cell count or CD4/CD8 ratio and the same parameters measured throughout the study, suggesting the importance of preinfection immune status as a determinant of disease progression. The negative correlations between the post-acute-phase IgM levels and the percentage of CD4(+) T cells at later times during the study suggest the potential prognostic value of this measurement.

Biomarkers to assess potential developmental immunotoxicity in children

Clinical tests are readily available for assessing severe loss of immune function in children with diseases such as AIDS or primary immunodeficiency. However tests that could reliably identify subtle immune changes, as might be expected to result from exposure to developmental immunotoxic agents, are not readily available. A number of tests are described which we believe have potential applicability for epidemiological studies involving developmental immunotoxicity. Several of the tests, such as T cell receptor rearrangement excision circles (TRECs) and cytokine measurements, while highly relevant from a biological standpoint, may be precluded from use at the current time, for either technical issues or insufficient validation. Immunophenotyping and measurement of serum immunoglobulin levels, on the other hand, are well validated. Yet they may require extraordinary care in experimental design and technical performance in order to obtain data that would consistently detect subtle changes, as these tests are not generally considered highly sensitive. Quantification of the immune response to childhood vaccine, while up to the present used sparingly, may represent an excellent indicator for developmental immunotoxicity when conducted under appropriate conditions.

A 5-week-old HIV-1–exposed girl with failure to thrive and diffuse nodular pulmonary infiltrates

A 5-week-old female infant with vertical HIV-1 exposure, progressive cough, and failure to thrive was given a diagnosis of bilateral diffuse nodular lung lesions. The child was without fever, leukocytosis, anemia, peripheral adenopathy, or hepatosplenomegaly, and the results of repeated blood tests for HIV-1 DNA were negative. A needle biopsy of the lungs revealed granulomatous inflammation and giant cells, with fungal organisms suggestive of Aspergillus species. A nitroblue tetrazolium dye test performed on the patient's blood specimen demonstrated absence of dye reduction, suggesting a diagnosis of chronic granulomatous disease. Further analysis revealed that the child had a deficiency of the p47(phox) component of the nicotinamide adenine dinucleotide phosphate oxidase system. Thus this child with vertical HIV-1 exposure and diffuse pulmonary nodules actually had an autosomal recessive form of chronic granulomatous disease. This case study clearly demonstrates that children with suspected HIV-1 infection might also need evaluation for primary immunodeficiency and that the clinical immunology laboratory is a powerful adjunct in coming to a correct diagnosis.

The AIDS disease of CD4C/HIV transgenic mice shows impaired germinal centers and autoantibodies and develops in the absence of IFN-gamma and IL-6

The mechanisms responsible for degeneration of germinal centers (GC) and follicular dendritic cell (FDC) networks during progression to AIDS remain elusive. Here, we show that CD4(+) T cells from CD4C/HIV-1 Tg mice, which develop a severe AIDS-like disease, express low levels of CD40 ligand. Accordingly, GC formation, FDC networks, and immunoglobulin isotype switching are impaired in these animals. However, Tg B cells respond to in vitro CD40 stimulation. Total serum IgG levels are reduced in Tg mice, whereas total IgM levels are increased with a significant amount showing DNA specificity. IFN-gamma- and IL-6-deficient CD4C/HIV Tg mice also develop the AIDS-like disease and produce auto-Ab. Thus, CD4C/HIV Tg mice have immune dysfunction accompanied by autoimmune responses.