Effect of flash-heat treatment on immunoglobulins in breast milk.
BACKGROUND
Heat-treated expressed breast milk is recommended by the World Health Organization as an option to reduce vertical HIV transmission in resource-poor regions. Flash-heat (FH) is a low technology pasteurization method developed for home use, but its effect on quantity and quality of breast milk immunoglobulins is unknown.


OBJECTIVE
To evaluate FH's effect on breast milk immunoglobulin levels and antigen-binding capacity.


METHODS
Fifty HIV+ mothers in South Africa provided breast milk. Part of each sample served as an unheated control; the remainder was flash-heated. Total and antigen-specific immunoglobulin A (IgA) and immunoglobulin G (IgG) were measured by enzyme-linked immunosorbent assay. Paired t test was performed on log-transformed data.


RESULTS
FH significantly decreased total IgA and IgG concentrations [geometric mean (geometric SD) 318.0 (1.9) vs. 398.2 (1.9) microg/mL and 89.1 (2.7) vs. 133.3 (2.5) microg/mL, P < 0.001 each]. Similar decreases in anti-HIV-1 gp120 IgG, anti-pneumococcal polysaccharide, and anti-poliovirus IgA occurred (P < 0.001 each). Although the latter was most affected, FH retained 66% of the antigen-binding ability. In contrast, binding capacity of IgA and IgG to influenza increased after FH (P = 0.029 and 0.025, respectively).


CONCLUSIONS
Most breast milk immunoglobulin activity survives FH, suggesting flash-heated breast milk is immunologically superior to breast milk substitutes. Clinical significance of this decreased immunoglobulin activity needs evaluation in prospective trials.
Department of Pediatrics, University of California Davis Medical Center, Sacramento, CA 95817, USA. caroline.chantry@ucdmc.ucdavis.edu
Caroline J
CJ
Chantry
Kiersten
K
Israel-Ballard
Zina
Z
Moldoveanu
Jan
J
Peerson
Anna
A
Coutsoudis
Lindiwe
L
Sibeko
Barbara
B
Abrams
D000907:Antibodies, Bacterial / Q000032:analysis / Q000276:immunology; D003906:Developing Countries; D005260:Female; D015483:HIV Antibodies / Q000032:analysis / Q000276:immunology; D015658:HIV Infections / Q000517:prevention & control* / Q000635:transmission / Q000821:virology; D006358:Hot Temperature; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis* / Q000276:immunology; D007074:Immunoglobulin G / Q000032:analysis* / Q000276:immunology; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control*; D008895:Milk, Human / Q000276:immunology* / Q000821:virology; D013019:South Africa; D013242:Sterilization / Q000379:methods*; D038301:Virus Inactivation
D000907:Antibodies, Bacterial; D015483:HIV Antibodies; D007070:Immunoglobulin A; D007074:Immunoglobulin G