Sudden infant death syndrome: no significant expression of heat-shock proteins (HSP27, HSP70)

In industrialized countries, sudden infant death is the most common cause of death in young children. Although prone sleeping position is a well-known risk factor, hyperthermia might also be important. Pathognomonic findings of premortem hyperthermia do not exist. During stress, including thermal effects, heat-shock protein (HSP) expression increases. This study investigated hyperthermia as a contributing or pathogenic factor for sudden infant death syndrome (SIDS). Immunohistochemical staining for HSP27 and HSP70 in the kidney, heart, and lung from 120 SIDS cases was examined. HSP70 immunostaining was negative in kidney, heart, and lung tissues in all cases and in tissues from the control group. HSP27 staining was positive in the kidney from one case, and was positive in the lungs (respiratory epithelia in 27 % of cases; vascular endothelia in 19 % of cases) and was negative in the heart. In the control group HSP27 was positive in 8 % of renal tubular tissues and in 29 % of renal vascular endothelia. Staining for HSP27 in lung tissues was positive in respiratory epithelia in 8 % of cases and for vascular endothelia in 29 %, whereas tissues from the heart were positive in only 4 %. The hypothesis of hyperthermia being a pathogenic factor for SIDS was not supported by immunohistochemical visualization of HSP70 or HSP27.