Confocal Raman characterization of different protein desorption behaviors from chromatographic particles.

Confocal Raman spectroscopy is a nondestructive analytical technique that combines the chemical information from vibrational spectroscopy with the spatial resolution of confocal microscopy. It was applied, for the first time, to measure protein desorption from chromatographic particles. Monoclonal antibody was loaded onto the Fractogel EMD SO3 (M) cation exchanger at either pH 5 or pH 4. Confocal Raman measurement suggests that only the protein loaded at pH 5 is able to release from chromatographic particles in the elution buffer. Detailed comparison of high-quality spectra indicates that, while proteins loaded at both pH values showed a predominant ß-sheet conformation, protein loaded at pH 4 has a broader amide I band with more intensity in the >1680 cm(-1) region. This small but clear and reproducible amide I bandwidth increase is not observed for protein in the solution state at pH 4. No definitive assignment of the increased Raman intensity in the >1680 cm(-1) region could be made, but it might be related to structural changes involved in the association of protein molecules in the adsorbed state, which helps to explain the nearly 100% retention under elution conditions of the monoclonal antibody adsorbed at pH 4 in chromatographic particles.

IgG4 related sclerosing disease with multiple organ involvements and response to corticosteroid treatment.

Great attention has been drawn toward the recently defined IgG4 related sclerosing disease, an entity incorporating autoimmune pancreatitis and other organ involvements, hypergammaglobulinemia and deposition of IgG4 in affected tissues. We demonstrate an index case of this disease with multiple organ involvements and an excellent response to corticosteroid treatment. A 69-year-old white man was diagnosed with IgG4 related sclerosing disease with involvement of lungs, pancreas, submandibular glands, lymph nodes, and kidney. In addition, the patient had polyclonal IgG hypergammaglobulinemia and hypocomplementemia. A renal biopsy showed tubulointerstitial nephritis with extensive lymphoplasmacytic infiltrate. Biopsy of the lung showed "inflammatory pseudotumor" with lymphocyte and plasma cell infiltration. IgG4 positive plasma cells were seen in the biopsy of submandibular gland and the kidney. Immuno-staining of the renal biopsy specimen showed vascular deposition of complement split product C4d. Corticosteroid treatment of 2 months showed complete resolution of the disease process. We demonstrate deposition of C4d in the IgG4 related tubulointerstitial nephritis for the first time.