Relative increase in IgG antibodies to Pseudomonas aeruginosa 60-kDa GroELin prediabetic patients with cystic fibrosis

In recent years research has focused on a possible connection between bacte rial infection and development of diabetes mellitus. In this study, serum a ntibody responses against bacterial antigens in diabetic and nondiabetic pa tients with cystic fibrosis (CF) were evaluated. The first part of the stud y included 252 CF patients of whom 46 (18%) had diabetes. This study showed that precipitating antibodies (precipitins) against Pseudomonas aeruginosa and other bacteria in crossed immunoelectrophoresis, and IgG antibodies ag ainst a 60-kD GroEL of P. aeruginosa, were highly variable and positively c orrelated with age. Patient material matched for age and sex showed no sign ificant difference between diabetic and nondiabetic CF patients in precipit ins or IgG antibodies to P. aeruginosa GroEL. Two longitudinal studies of 9 and 5 y using retrospectively selected sera from 29 prediabetic and 29 cro ss-matched nondiabetic CF patients were performed. As to precipitins agains t P. aeruginosa, we found no difference between the prediabetic and the non diabetic group of patients during the study period. The study revealed, how ever, a significant increase of 24.6% (p = 0.008) of IgG antibodies against P. aeruginosa 60-kD GroEL, 3-12 mo before the onset of diabetes in patient s with CF, compared with an overall increase of 5% to 6% per year in both g roups during the observation period. This study shows that diabetes in CF a ppears after a peak of serum IgG antibodies against GroEL and indicates tha t development of diabetes in CF patients may not only be caused by a progre ssive fibrosis of the pancreatic tissue, but may be augmented by a short-te rm specific immunologic reaction, initially triggered by an ongoing and pro gressive pulmonary infection.