Inhibitory effect of maternal antibody on mother‐to‐child transmission of human T‐lymphotropic virus type I

Abstract

In order to evaluate the protective role of the maternal antibody against mother-to-child transmission of HTLV-I, we followed a total of 780 children born to HTLV-I carrier mothers by investigating the level of anti-HTLV-I antibody transferred in utero, decline of the maternal antibody and seroconversion in post-natal life. The anti-HTLV-I antibody was positively detected within the first 3-6 months of life and declined at 6-12 months after birth in all children. After the maternal antibody declined, seroconversion occurred in some of the children following either breast feeding or bottle feeding. The seroconversion rates of short-term (less than or equal to 6 months) and long-term (greater than or equal to 7 months) breast feeders were 4.4% (4/90 cases) and 14.4% (20/139 cases), and the rate of bottle feeders was 5.7% (9/158 cases). Long-term breast feeding yielded more seroconverters than short-term breast feeding; 14.4% (20/139 cases) vs. 4.4% (4/90 cases), RR = 3.68, p = 0.018. The seroconversion rate of short-term breast feeders was nearly equal to that of bottle feeders; 4.4% (4/90 cases) vs. 5.7% (9/158 cases), RR = 0.770, p = 0.471. When neonatal lymphocytes were cultured with breast milk cells of HTLV-I carrier mothers, the in vitro infection of HTLV-I was inhibited by the addition of HTLV-I-seropositive cord-blood plasma. Our results suggest that the maternal antibody may inhibit HTLV-I infection by short-term breast feeding but not by long-term breast feeding after decline of the maternal antibody.

HTLV‐1 provirus load in peripheral blood lymphocytes of HTLV‐1 carriers is diminished by green tea drinking

“…Ninety-five subjects were recruited from asymptomatic HTLV-1 carriers living in Kagoshima prefecture, an HTLV-1 endemic area in southern Kyushu, Japan, all of whom had given informed consent to answer a questionnaire regarding their lifestyle (such as habitual green tea consumption, smoking and alcohol drinking habits), to make daily records of taking capsules of green tea extract powder, and to donate peripheral blood for monthly examination of HTLV-1 provirus load. The female subjects were recruited from those who had participated in the surveillance for mother-to-child transmission of HTLV-1, 6) and the male subjects were their husbands and relatives. The subjects were randomly assigned to two groups by the minimization method using age and gender as risk factors: 47 subjects who took the capsulated green tea extract powder, designated as the GT(+) group and 48 subjects who lived ad libitum without intake of any green tea capsules, designated as the GT(-) group.…”

“…[1][2][3][4] The major route of HTLV-1 infection is mother-to-child transmission via breast milk, and both bottlefeeding and short-term breast-feeding reduce the risk of neonatal infection with HTLV-1. 5,6) However, once HTLV-1 infects T lymphocytes and integrates its provirus into the host genome, the virus cannot be excluded from the body. A high level of HTLV-1 provirus load in circulating lymphocytes of HTLV-1 carriers is a risk factor for HTLV-1-related diseases.…”

Current views in HTLV-I-associated adult T-cell leukemia/lymphoma

“…Motherto-child transmission is associated with prolonged breast-feeding in the postnatal period [7][8][9][10] and has been associated with an increased risk of developing ATLL. HTLV-1 can be sexually transmitted with a higher transmission efficiency from male to female than from female to male [11,12].…”

Monographs on the Evaluation of Carcinogenic Risks to Humans

“…HTL V -I-seropositive mothers become infected with the virus Hino et al, 1987a,b;Hino, 1990a;Tajima et aL., 1990a;Takahashi et al, 1991;Ando et al, 1993;Monplaisir et aL., 1993;Hino et al, 1994). This transmission is linked to the presence of HTL V -1 provirus in mononuc1ear ceIls in breast milk (Kinoshita et al, , 1985a.…”

“…Mother-to-chi1d transmission represents a major mode of transmission of HTLV-I in endemic areas, mainly due to breast-feeding beyond six months (Hino, 1990a;Tajima et aL., 1990a;Takahashi et al, 1991;Monplaisir et aL., 1993;Wiktor et aL., 1993;Hino et al, 1994), after which time the protective IgG maternaI antibodies decline . Seroconversion (the development of detectable specific antibodies to the virus in the serum) in children occurs between 18 and 24 months of age .…”