ESPE Abstracts

Background/Aim: Although there are many well-known components that affect the growth response to recombinate growth hormone (rGH), its effect on total height gain is still not fully predictable. Current knowledge on the relationship between growth response to rGH and its immunogenicity is limited. The aim of the study was to reveal its relationship with the antibody formation against rGH and growth-promoting effect.

Materials and Methods: This was a cross-sectional study involving 193 children presenting with short stature, 111 of whom were treated for GH due to growth hormone deficiency (GHD), 45 for non-endocrin, and 37 for idiopathic short stature (ISS). The distribution of the participants according to treatment years was as follows: 24, 34, 46, 39, 21, 29 children; at onset, first, second, third, 4^th, and ≥5^th years on treatment. GH antibody (GH-Ab) and total IgE assays were studied from all and 97 participants, respectively. The relationship between clinical features associated with growth response and antibody seropositivity was evaluated.

Results: Seropositivities for GH-Ab and total IgE were detected in 103 (53.3%) and 25 (25.7%), respectively. . The number of GH-Ab positive patients was higher in the ISS group (67.5%) (P = 0.013). In 15 of 24 (62.5%) patients whose test was studied, GH-Ab seropositivity was detected before treatment. In all three groups, first-year height velocity was found to be lower in GH-Ab positive patients than in GH-Ab negative patients (GHD; 8.62±2.97 vs. 10.91±3.63cm/year, ISS; 5.63±0.11 vs. 8.30±1.79cm/year, non-endocrin; 7.75±1.26 vs. 10.12±2.26cm/year; P = 0.003, P = 0.003, and P = 0.001, respectively). Similarly, first-year height velocity was found to be lower in IgE positive patients (7.01±3.25 vs. 8.93±2.16; P = 0.032). In the non-endocrin group, first-year height velocity was negatively correlated with mean GH-Ab and total IgE levels (r = -0.468, P = 0.039; r=-0.448, P = 0.042, respectively)

Conclusion: This study showed that GH-Ab formation is common in children with short stature, especially those with ISS, before and during rGH treatment, and also GH-Ab positivity is associated with lower first-year height velocity. It also indicates that GH-Abs both could play a role in the etiology of GH-related short stature and that immunogenicity against rGH could have an impact on first-year height velocity.