Immunological manifestations of HIV-infected children

Simple markers for the detection of severe immunosuppression in children with HIV infection in highly resource-scarce settings: experience from the Democratic Republic of Congo

OBJECTIVES

The decision to initiate the antiretroviral therapy in HIV-infected children living in poor countries is compromised by lack of resources. The objective of this study is to identify simple clinical and biological markers other than CD4+ count and viral load measurement that could help the decision to introduce antiretroviral treatment and to monitor patients.

METHODS

A cross sectional study was conducted between January and March 2005 in Kinshasa, Democratic Republic of Congo.

RESULTS

Eighty-four children infected with HIV were recruited. In this cohort, the lymphocytes (P = 0.001) and CD4 (P = 0.0001) were significantly lower in children with immunological stage 3 and viral load (P = 0.027) was significantly higher in children at the same immunological stage. Reticulocytes (r = +0.440), white blood cells count (r = +0.560), total lymphocytes (r = +0.675) and albumin (r = +0.381) showed positive significant correlations with CD4. Haemoglobin (r = - 0.372), Haematocrit (r = - 0.248), red blood cells (r = - 0.278) and CD4 (r = - 0.285) showed negative significant correlations with viral load. Neutropaenia (P = 0.02), enlarged nodes (P = 0.005) and oral candidiasis (P = 0.04) were associated with viral load >10,000 copies/ml. Oral candidiasis (P = 0.02) was associated with CD4 level < 15%.

CONCLUSION

Oral candidiasis, enlarged nodes, total lymphocytes count, neutropaenia and albumin predict severe immunodepression. These clinical and biological markers may guide the clinician in making the decision to initiate antiretroviral therapy in highly resource-scarce settings.

Humoral immune responses to Pneumocystis jirovecii antigens in HIV-infected and uninfected young children with pneumocystis pneumonia

Background

Humoral immune responses in human immunodeficiency virus (HIV)-infected and uninfected children with Pneumocystis pneumonia (PcP) are poorly understood.

Methods

Consecutive children hospitalized with acute pneumonia, tachypnea, and hypoxia in South Africa were investigated for PcP, which was diagnosed by real-time polymerase chain reaction on lower respiratory tract specimens. Serum antibody responses to recombinant fragments of the carboxyl terminus of Pneumocystis jirovecii major surface glycoprotein (MsgC) were analyzed.

Results

149 children were enrolled of whom 96 (64%) were HIV-infected. PcP occurred in 69 (72%) of HIV-infected and 14 (26%) of HIV-uninfected children. HIV-infected children with PcP had significantly decreased IgG antibodies to MsgC compared to HIV-infected patients without PcP, but had similar IgM antibodies. In contrast, HIV-uninfected children with PcP showed no change in IgG antibodies to MsgC, but had significantly increased IgM antibodies compared to HIV-uninfected children without PCP. Age was an independent predictor of high IgG antibodies, whereas PcP was a predictor of low IgG antibodies and high IgM antibodies. IgG and IgM antibody levels to the most closely related MsgC fragments were predictors of survival from PcP.

Conclusions

Young HIV-infected children with PcP have significantly impaired humoral immune responses to MsgC, whereas HIV-uninfected children with PcP can develop active humoral immune responses. The children also exhibit a complex relationship between specific host factors and antibody levels to MsgC fragments that may be related to survival from PcP.

Alteration of serum beta 2-microglobulin in oral carcinoma

Serum β(2)-microglubin (β(2)-m) levels were measured in oral carcinoma patients and compared with normal healthy controls. It was observed that there was a significant rise in serum β(2)-microglobulin in oral carcinoma patients. Progressively higher values were obtained as the cancer advanced clinically. Therefore the estimation of serum β(2)-microglobulin may be useful as one of a battery of tests in the assessment of oral carcinoma patients.

Altered frequency and phenotype of CD4+ forkhead box protein 3+ T cells and its association with autoantibody production in human immunodeficiency virus-infected paediatric patients

The association between immune dysfunction and the development of autoimmune pathology in patients with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) is not clear. The frequency and phenotype of regulatory T cells, as well as the presence of autoantibodies, were evaluated in a paediatric cohort of HIV-infected patients without clinical evidence of autoimmune disease. Lower absolute counts but higher percentages of total CD4(+) forkhead box protein 3 (FoxP3)(+) T cells were recorded in children with severe immunosuppression than in those without evidence of immunosuppression. The frequencies of classical CD4(+) CD25(+) FoxP3(+) regulatory T cells were not altered, whereas CD4(+) FoxP3(+) CD25(-) T cells were found increased significantly in patients with severe immunosuppression. Like classical regulatory T cells, CD4(+) FoxP3(+) CD25(-) T cells display higher cytotoxic T-lymphocyte antigen 4 (CTLA-4) but lower CD127 expression compared with CD4(+) FoxP3(-) CD25(+) T cells. An improvement in CD4(+) T cell counts, along with a decrease in viral load, was associated with a decrease in CD4(+) FoxP3(+) CD25(-) T cells. The majority of the patients with severe immunosuppression were positive for at least one out of seven autoantibodies tested and displayed hypergammaglobulinaemia. Conversely, HIV-infected children without evidence of immunosuppression had lower levels of autoantibodies and total immunoglobulins. A decline in CD4(+) FoxP3(+) T cell numbers or a variation in their phenotype may induce a raise in antigen exposure with polyclonal B cell activation, probably contributing to the generation of autoantibodies in the absence of clinical autoimmune disease.