Correlation between CD4+ lymphocyte counts, concurrent antigen skin test and tuberculin skin test reactivity in human immunodeficiency virus type 1-infected and -uninfected children with tuberculosis.
BACKGROUND
HIV-infected children are at high risk of developing tuberculosis after infection by Mycobacterium tuberculosis. Emphasis is placed on tuberculin skin testing (TST) for diagnosing tuberculosis in children; however, its value in HIV-infected children is controversial.


OBJECTIVE
To determine whether concurrent antigen testing and/or CD4+ lymphocyte counts help in the interpretation of the TST in children with tuberculosis.


METHODS
Children eligible for the study were diagnosed as having tuberculosis on clinical criteria. CD4+ lymphocyte counts and delayed-type hypersensitivity (DTH) test, using the CMI Multitest were performed when tuberculosis was diagnosed.


RESULTS
One hundred thirty children were enrolled. Tuberculin reactivity was lower in HIV-infected children at all cutoff levels than in HIV-uninfected children (P < 0.0001). The positive predictive value of normal CD4+ lymphocyte counts in predicting tuberculin reactions of > or =5 mm (in HIV-1-infected) and > or =10 mm (in HIV-uninfected patients) were 50 and 80.3%, respectively (P < 0.0001). An intact DTH reaction to the CMI Multitest in predicting reactions of > or =5 mm and > or =10 mm to tuberculin in HIV-infected and -uninfected children were 55 and 76%, respectively (P < 0.001). Kwashiorkor was responsible for 53.3% of false-negative TST in HIV-uninfected children with normal CD4+ lymphocyte counts.


CONCLUSIONS
TST is of limited value as an adjunct in diagnosing tuberculosis in HIV-infected children. CD4+ lymphocyte counts and concurrent DTH testing are not useful for predicting tuberculin reactivity in HIV-infected patients with tuberculosis.
Madhi
S A
SA
Department of Paediatrics, University of the Witwatersrand, Johannesburg, South Africa.
Gray
G E
GE
Huebner
R E
RE
Sherman
G
G
McKinnon
D
D
Pettifor
J M
JM
D017088:AIDS-Related Opportunistic Infections / Q000175:diagnosis* / Q000276:immunology; D018791:CD4 Lymphocyte Count; D002648:Child; D002675:Child, Preschool; D017449:Dermatitis, Allergic Contact / Q000209:etiology / Q000276:immunology*; D015658:HIV Infections / Q000150:complications / Q000276:immunology; D015497:HIV-1 / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D011446:Prospective Studies; D012882:Skin Tests; D014374:Tuberculin Test / Q000009:adverse effects; D014376:Tuberculosis / Q000150:complications / Q000175:diagnosis* / Q000276:immunology