require($_SERVER["DOCUMENT_ROOT"]."/bitrix/modules/main/include/prolog_before.php");
use Bitrix\Iblock\SectionTable;
$res = SectionTable::getList([
"filter" => ["IBLOCK_ID" => 4, "ACTIVE" => "Y", "DESCRIPTION" => '%'.$_REQUEST['q'].'%'],
"select" => ["*"]
])->fetchAll();