Immune markers of disease severity and treatment response in pediatric acquired aplastic anemia.
BACKGROUND
To investigate the immune status among pediatric patients with aplastic anemia (AA) and explore PNH-status, T-regulatory and NK-cell frequency as potential markers of clinical response.


METHODS
Data were retrospectively analyzed from twenty-six patients diagnosed with AA. PNH populations, T- and NK-subsets were determined via flow cytometry.


RESULTS
At diagnosis, 9/23 patients with severe AA (SAA) versus 1/3 with moderate AA (MAA) were PNH(pos) . Among PNH(pos) patients treated with ATG based immunosuppression, 2/6 had a complete response (CR), while 4/6 had a partial response (PR), similarly 2/6 PNH(neg) patients had a CR and 4/6 had a PR. Lymphocyte subset immunophenotyping revealed that T-regulatory cells represented 7.2% of total lymphocytes at diagnosis. Their frequency varied with disease severity (5.5% for SAA and 14.1% for MAA) and response (8.9% for CR and 1.5% for PR), generally increasing following therapy with IST (14.6%). The NK cell frequency was not substantially different based on disease severity or response.


CONCLUSIONS
Neither PNH cell populations, nor NK cell frequency corresponded with disease severity or response. T-regulatory cell frequency, although not statistically significant given the small sample size, corresponded with both severity and response, indicating potential utility as a prognostic tool.
Departments of Pediatrics and Cell & Developmental Biology, Papé Family Pediatric Research Institute, Oregon Stem Cell Center, Oregon Health & Science University, Portland, Oregon 97239, USA.
Kathryn S
KS
Sutton
Evan B
EB
Shereck
Eneida R
ER
Nemecek
Peter
P
Kurre
D000293:Adolescent; D000741:Anemia, Aplastic / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology*; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry; D006457:Hemoglobinuria, Paroxysmal / Q000188:drug therapy / Q000276:immunology / Q000473:pathology; D006801:Humans; D016130:Immunophenotyping; D007223:Infant; D007694:Killer Cells, Natural / Q000276:immunology*; D008297:Male; D012189:Retrospective Studies; D013601:T-Lymphocytes / Q000276:immunology*
D000970:Antineoplastic Agents