Visceral Leishmaniasis in Human Immunodeficiency Virus (HIV)-Infected and Non-HIV-Infected Patients : A Comparative Study

We studied B-lymphocyte function in 12 homosexual male patients with the acquired immunodeficiency syndrome, 5 healthy homosexual men, and 12 heterosexual controls. In comparison with the heterosexual controls, the patients were found to have elevated numbers of cells spontaneously secreting immunoglobulin, decreased B-cell proliferative responses to T-cell-independent B-cell mitogens, and qualitatively deficient helper T cells. The hyperactive spontaneous B-cell responses as well as the refractoriness to signals for T-cell-independent B-cell activation were highly suggestive of an in vivo polyclonal activation of B cells and may have been responsible for the manifestations of B-cell hyperreactivity, such as hypergammaglobulinemia, seen in these patients. We conclude that the scope of immune dysfunction in the acquired immunodeficiency syndrome involves B cells as well as T cells.

We evaluated three cellular and five serologic markers that are affected by infection with the human immunodeficiency virus type 1 (HIV-1) for their ability to predict the progression to clinical acquired immunodeficiency syndrome (AIDS). The cellular markers were the number of CD4+ T cells, the number of CD8+ T cells, and the ratio of CD4+ T cells to CD8+ T cells. The serologic markers were the serum levels of neopterin (a product of stimulated macrophages), beta 2-microglobulin, soluble interleukin-2 receptors, IgA, and HIV p24 antigen. We evaluated the usefulness of these measures as markers of the progression to AIDS prospectively, over four years, in a cohort of 395 HIV-seropositive homosexual men who were initially free of AIDS. CD4+ T cells (expressed as an absolute number, a percentage of lymphocytes, or a ratio of CD4+ to CD8+ T cells) were the best single predictor of the progression to AIDS, but the serum neopterin and beta 2-microglobulin levels each had nearly as much predictive power. The neopterin level appeared to be a slightly better predictor than the beta 2-microglobulin level. The levels of IgA, interleukin-2 receptors, and p24 antigen had less predictive value. A stepwise multivariate analysis indicated that the best predictors, in descending order, were CD4+ T cells (the percentage of lymphocytes or the CD4+: CD8+ ratio), the serum level of neopterin or beta 2-microglobulin, the level of IgA, that of interleukin-2 receptors, and that of p24 antigen. The last three markers had little additional predictive power beyond that of the first two. We conclude that of the eight markers studied, progression to AIDS was predicted most accurately by the level of CD4+ T cells in combination with the serum level of either neopterin or beta 2-microglobulin. At least one of these two serum markers, which reflect immune activation, should be used along with measurement of CD4+ T cells in disease-classification schemes and in the evaluation of responses to therapy.

During an epidemiological study of visceral leishmaniasis in an endemic region of Brazil, new perspectives emerged on a subclinical form of the disease. A group of 86 children with antibody to Leishmania were identified. None of these children had a history of leishmaniasis. The children were segregated into four groups: One group remained asymptomatic (n = 20), whereas another developed classic kala-azar within weeks of the index serology (n = 15). The remaining 51 patients initially had subclinical disease; 13 (25%) of these patients progressed to classic kala-azar (mean, five months). The others (75%) resolved their illness after a prolonged period (mean, 35 months). The initial illness in the subclinical group was characterized by hepatomegaly, frequent splenomegaly, intermittent cough, diarrhea, and low-grade fever. Malaise and poor weight gain were common. Giemsa-stained smears and cultures of bone marrow aspirates were usually negative for Leishmania in the absence of symptoms of classic kala-azar.