Basic HTML Version
46
ICCS 2012
P29
PEDIATRIC REFERENCE RANGES FOR PERIPHERAL B
CELL SUPOPULATIONS BASED ON THE EUROCLASS
CLASSIFICATON OF OF CVID
Michele Paessler
1,2
, Leslie Koutafaris
2
, Joe McMann
2
1
University of Pennsylvania School of Medicine,
2
Children’s
Hospital of Philadelphia
The evaluation of pediatric patients for immunodeficiencies,
including B cell immunodeficiencies and common variable
immunodeficiency (CVID) are common. In recent years,
flow cytometric studies have demonstrated various B cell
subsets and the basis for a new classification scheme
defining subgroups in common variable immunodeficiency.
These specific B cell subsets correlate both clinically and
prognostically with CVID and also have diagnostic value.
However, the data from these studies were based largely
on adults and are not applicable to the pediatric population.
Previous studies of pediatric reference ranges demonstrated
significant differences from adult values and changes in
the B cell compartment during development, particularly in
infancy and early childhood. Immunphenotyping is a useful
tool in diagnosing immunologic and hematologic disorders
and when values fall outside of the defined normal ranges
it may indicate disease and the need for further work-up.
Evaluating the pediatric patient for immunodeficiencies,
including CVID, can be challenging due to the lack of
reliable reference ranges. Reference ranges for B cell
subsets in children have been hampered due to significant
age-related changes in the developing immune system in
the pediatric population and small numbers of patients in
previous studies. At the Children’s Hospital of Philadelphia,
we are comprehensively evaluating age-related B cell
subsets in a healthy cohort of children from birth to 21 years
using 10-color flow cytometry (Beckman Coulter Galios).
The age ranges for the study are: <6 months, 6 months-
1year, 1-2, 2-4, 5-8, 8-12, 12-18 years. In this study, flow
cytometry is performed on PBMCs and analyzed by gating
on lymphocytes by CD45 versus side scatter. B cells are
then identified by CD19 positivity. The B cell subsets in our
comprehensive B cell panel include those descrfibed in the
EUROclass trial. The following immunophenotypic subtypes
of CD19+ B cells are analyzed: IgD+/CD10+; CD40+, IgD+/
IgM+; CD27+/IgD+; CD27+/IgD-; CD27+/IgM+; CD27+/IgM-
; CD27-/IgM+; IgG/CD20-; CD5+/CD19+; CD21+/CD38+;
CD38+/IgM+, and CD38+/IgM-. The values are given as a
percentage of B cells and total events. Thus far 62 patients
have been analyzed and the study is in progress. To date,
we have seen a decrease in the percentages of all B cells
subsets compared to those published values in other
pediatric cohorts and adults. The most significant differences
we have seen are in naive B cells and in both switched and
unswitched memory B cells, which were ~30-40% less than
those published age-related values. This finding further
documents the need for age-related reference values in a
large pediatric cohort.
P30
FLOW CYTOMETRIC AND PROTEOMIC FEATURES
OF PLATELET-FREE PLASMA MICROPARTICLES IN
THALASSEMIA
Kovit Pattanapanyasat
1,2
, Porntip Chaichompoo
1,3
,
Panida Kumya
1
, Ladawan Khowawisetsut
1
, Wararat
Chiangjong
1,4
, Sakdithep Chaiyarit
1,4
, Nutkridta Pongsakul
1,4
,
Noppadol Sirithanaratanakul
5
, Suthat Fucharoen
3
, Visith
Thongboonkerd
1,4
1
Office for Research and Development, Faculty of Medicine
Siriraj Hospital, Mahidol University,
2
Center for Emerging
and Neglected Infectious Diseases, Mahidol University,
3
Thalassemia Research Center, Institute of Molecular
Biosciences, Mahidol University,
4
Center for Research
POSTER ABSTRACTS