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Acquired protein S deficiency in children infected with human immunodeficiency virus
R W Sugerman1, J A Church, J C Goldsmith
1Division of Clinical Immunology, University of Southern California School of Medicine, Los Angeles, USA.
Insights
Acquired protein S deficiency is common in children with human immunodeficiency virus (HIV). This coagulation abnormality may increase the risk of blood clots in this population.
Area of Science:
- Pediatric Hematology
- Infectious Diseases
- Coagulation Science
Background:
- Human immunodeficiency virus (HIV) infection can affect various bodily systems, including hemostasis.
- Protein S is a crucial vitamin K-dependent anticoagulant protein that regulates coagulation.
- Acquired deficiencies in coagulation inhibitors can lead to thrombotic events.
Purpose of the Study:
- To determine the prevalence of acquired protein S deficiency in children with HIV.
- To identify clinical and laboratory factors associated with protein S deficiency in this cohort.
Main Methods:
- Evaluated 34 HIV-infected children (ages 2-18) for protein S levels (total, free, functional).
- Assessed other coagulation parameters, CD4+ T cell counts, and viral markers.
- Compared findings based on HIV clinical classification and CD4+ counts.
Main Results:
- 76.5% had decreased free protein S; 55.9% had decreased functional protein S.
- Prevalence of deficiency increased with HIV disease severity (Class C > Class A/B > Class N).
- Lower CD4+ counts (<200/mm3) were associated with a higher prevalence of protein S deficiency.
Conclusions:
- Acquired protein S deficiency is a frequent finding in HIV-infected children.
- The high prevalence suggests an elevated risk for thrombotic complications in this population.
- Further research is warranted to elucidate the clinical implications and management strategies.
Objectives:
To determine the prevalence of an acquired deficiency of protein S, a coagulation inhibitor, in children infected with the human immunodeficiency virus (HIV) and to identify clinical and laboratory features associated with this coagulation abnormality.
Methods:
A convenience sample of HIV-infected children, ages 2 to 18 years, was evaluated for total, free and functional protein S; total and functional protein C; prothrombin and activated partial thromboplastin times; fibrinogen; antithrombin III activity; dilute Russell viper venom time; IgG anticardiolipin antibodies; von Willebrand factor antigen; C4b-binding protein; CD4+ T lymphocyte counts; HIV p24 antigen concentration; and serum beta 2-microglobulin concentrations.
Results:
Thirty-four subjects were evaluated. Twenty-four subjects were infected perinatally and 10 by transfusion. Nine of the subjects were CDC Class N (asymptomatic), 13 were Class A/B (symptomatic without AIDS-defining condition) and 12 were Class C (AIDS). None had previously documented thrombosis, nephrosis or significant hepatic dysfunction. Twenty-six subjects (76.5%) had decreased free protein S, and 19 (55.9%) had functional protein S < 2 SD below the mean of laboratory controls. Decreased functional protein S was seen in 33.3% of Class N, 53.8% of Class A/B and 75.0% of Class C subjects. The prevalence of decreased total and functional protein S was greater in those with absolute CD4+ T lymphocyte counts < 200/mm3 compared to those with CD4+ counts > or = 200/mm3 (75.0% vs. 38.9%; chi square, 4.48, P = 0.034). A trend toward negative correlation was observed between protein S and duration of HIV infection only for Class N subjects. No linear correlation was seen between protein S and CD4+ T lymphocyte counts; and no significant relationships were observed between protein S values and CMV status, HIV p24 antigen, C4b-binding protein, von Willebrand factor antigen, IgG anti-cardiolipin antibodies or serum beta 2-microglobulin values.
Conclusions:
Acquired protein S deficiency is common in HIV-infected children. The high prevalence of this anticoagulant abnormality suggests an increased risk for thrombotic complications in this population.