A multicenter evaluation of the PanLeucogating method and the use of generic monoclonal antibody reagents for CD4 enumeration in HIV-infected patients in Thailand.
BACKGROUND
The current method of CD4 enumeration in Thailand, based on the three-tube, three-color method recommended by the Centers for Disease Control and Prevention, is expensive and thus unavailable to most patients who have the human immunodeficiency virus (HIV). Less expensive, simpler protocols (i.e., PanLeucogating and primary CD4 gating) have been described but require more published validation data to gain widespread acceptance. We describe a multicenter evaluation of the PanLeucogating method.


METHODS
The PanLeucogating method using generic reagents was evaluated in comparison with the standard three-tube, three-color method using commercial reagents. Percentage of CD4+ T cells among lymphocytes and absolute CD4+ T-cell counts were determined in 611 HIV-infected individuals recruited from four sites. Linear regression and Bland-Altman tests were used for statistical analysis.


RESULTS
The correlation of percentage of CD4+ T cells and absolute CD4+ T-cell counts obtained with the PanLeucogating strategy and the standard predicate method was high (r2 = 0.96 and 0.95, respectively, for the entire study population and r2 > 0.95 and 0.93, respectively, for each study group). Absolute CD4+ T-cell counts of the overall study pool and of the two subdivisions of absolute CD4+ T-cell counts (i.e., 0-250 cells/microl and > 250 cells/microl) derived from the two methods demonstrated excellent agreement, with mean biases of +18 cells/microl, +11 cells/microl, and +24 cells/microl, respectively.


CONCLUSIONS
These observations demonstrate that CD4 enumeration by PanLeucogating is reliable and can be performed to an identical standard in a quality-assured network of collaborating laboratories as a new cost-effective approach to HIV monitoring.
Pattanapanyasat
Kovit
K
Center of Excellence for Flow Cytometry, Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand. grkpy@mahidol.ac.th
Shain
Hla
H
Noulsri
Egarit
E
Lerdwana
Surada
S
Thepthai
Charin
C
Prasertsilpa
Varipin
V
Likanonsakul
Sirirat
S
Yothipitak
Prakit
P
Nookhai
Somboon
S
Eksaengsri
Achara
A
D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology* / Q000628:therapy; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D015704:CD4 Antigens / Q000032:analysis / Q000096:biosynthesis; D018791:CD4 Lymphocyte Count / Q000191:economics / Q000379:methods*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology; D003585:Cell Biology; D002452:Cell Count / Q000191:economics* / Q000379:methods*; D003362:Cost-Benefit Analysis; D006801:Humans; D016130:Immunophenotyping; D016014:Linear Models; D008214:Lymphocytes / Q000166:cytology; D015166:Monitoring, Immunologic / Q000379:methods; D011786:Quality Control; D013601:T-Lymphocytes / Q000166:cytology; D013785:Thailand
D000911:Antibodies, Monoclonal; D015704:CD4 Antigens