Increased expression of HDJ-2 (heat shock protein 40) and heat shock protein 70 in biopsy specimens of transplanted human lungs

Background: Heat shock proteins are expressed during several forms of stress and inflammation. This study was done to determine whether the expression of heat shock protein HDJ-2 (heat shock protein 40), heat shock protein 60, and heat shock protein 70 are increase during rejection in human pulmonary allografts. Methods: Thirty-five transbronchial biopsy specimens were obtained from adult lung transplant recipients. Histologic analysis and assessment of heat shock protein HDJ-2, heat shock protein 60, and heat shock protein 70 mRNA expression was performed. Total RNA was extracted, reverse transcribed, and amplified by polymerase chain reaction with oligonucleotide primers specific for the heat shock proteins. The identity of the amplified message was verified by Southern blot and slot blot analysis. Results: The expression of heat shock protein HDJ-2 was significantly higher in samples from lung transplant recipients undergoing rejection when compared with recipients without rejection or infection. Heat shock protein 70 expression was also increased in rejection. Expression of heat shock protein 60 did not show any increase in recipients with no evidence of rejection and infection or transplant recipients with rejection or infection. Serial analysis of heat shock protein HDJ-2 and heat shock protein 70 obtained in biopsy specimens during and after rejection showed a decrease of heat shock protein HDJ-2 and heat shock protein 70 expression after resolution of lung rejection. Conclusion: Our data demonstrate that the expression of heat shock protein HDJ-2 and heat shock protein 70 increases during lung rejection. However, only heat shock protein HDJ-2 was able to differentiate between rejection and infection. Measurement of heat shock protein HDJ-2 in transbronchial biopsy specimens may assist in the differential diagnosis between rejection and infection in lung transplant recipients.