Effect of hypogammaglobulinemia after lung transplantation: a single-institution study.

OBJECTIVES Recent studies suggest hypogammaglobulinemia (HGG) is frequently associated with infection after solid organ transplantation, although the effects of HGG after lung transplantation are not well recognized. We investigated the incidence and degree of HGG after lung transplantation and its association with infection. METHODS A retrospective cohort study analysing pre- and post-transplant IgA, IgG and IgM levels and infectious events in patients undergoing living-donor lobar and cadaveric lung transplantation at Kyoto University Hospital between June 2008 and March 2013. RESULTS Overall, post-transplant immunoglobulin (Ig) levels were significantly lower than pretransplant levels. In almost all patients who received transplants for bronchiolitis obliterans (BO) after haematopoietic stem cell transplantation (HSCT), interstitial lung diseases and bronchiectasis, post-transplant IgA and IgG levels decreased and were significantly lower than pretransplant levels; pre- and post-transplant IgA and pretransplant IgG levels were significantly lower in patients transplanted for BO after HSCT than in the others. Post-transplant IgG levels in patients transplanted for BO after HSCT also tended to be lower than those in the others, but not significantly. Nineteen of 29 patients had HGG after lung transplantation (65.5%) and had more infections than the normal gammaglobulinemia group, although there was no significant difference. Among them, 2 patients transplanted for BO after HSCT with quite low HGG had severe pneumonia and finally died. CONCLUSIONS Post-transplant Ig levels were significantly lower than pretransplant levels. Although without significant difference, HGG patients had more infections, above all, those with severe HGG transplanted for BO after HSCT could have lethal infections. Ig levels in HGG should be monitored carefully because severe HGG was associated with poor prognosis.