OBJECTIVETo investigate possible relationship between expression of surfactant protein B (SP-B) gene product and neonatal respiratory distress syndrome (NRDS) in Han ethnic group.

METHODUnrelated 20 cases with NRDS of Han ethnic group were selected as NRDS group while unrelated 20 diseases cases of Han ethnic group with diseases were selected as control group. The cases in the control group had congenital heart disease or bronchopulmonary dysplasia or persistent pulmonary hypertension. Blood sample was taken from every case. Lung tissues were taken from the patients who died half an hour after death in the two groups. Expression of SP-B in lung tissue was determined with immunohistochemical tecnique. Genetic deficiency variant of SP-B intron IV was screened with polymerase chain reaction (PCR).

RESULTSTwo cases at gestational age 26 weeks and one case at gestational age 34 weeks and two cases at gestational age 42 weeks of NRDS groups had lower level expression of SP-B in lung tissue than those at the same age of NRDS. Expression of SP-B in lung tissue of control group increased with gestational age, but no such phenomenon was found in NRDS group. Further, two cases at gestational age 42 weeks of NRDS group had genetic deficiency variant of SP-B intron IV with gene analysis of five cases who had lower expression of SP-B. Clinical data suggest that patients at 42 weeks of gestational age had severe illness.

CONCLUSIONSDecrease of SP-B expression may participate in occurrence of NRDS, genetic deficiency variant of SP-B intron IV exists in the NRDS cases of Han ethnic group of China.