Abstract
An unusual B-cell proliferation was noted in an individual (Tun) which was characterized by the presence of two separate populations of chronic lymphocytic leukemia (CLL) cell staining on the surface and in the cytoplasm for either IgG(k) or IgA(k). Utilizing an idiotypic antiserum prepared from the associated serum monoclonal IgG(k) protein the idiotype was detected on the surface and in the cytoplasm of both the IgG- and IgA-bearing cell populations. These observations are consistent with a common clonal origin and a switch mechanism involving IgG and IgA synthesis. Sequential-labeling of Surface Ig and intracellular Ig with antisera conjugated to opposite fluorochromes documented the progressive maturation of the terminal differentiation of the IgA-bearing cell population at a level before morphologically distinct plasma cells. The distribution and pattern of surface and cytoplasmic IgG and IgA staining in individual cells suggest that the direction of switching is from IgG to IgA synthesis. The demonstration of shared idiotypic specificity between the IgG- and IgA-bearing populations is consistent with a transition in Ig heavy chain synthesis resulting from an alternation in the CH gene. It is concluded that certain CLL clones may manifest a switch from IgG to IgA synthesis at a level of B-cell differentiation which encompasses both the B lymphocyte and the Ig-synthesizing plasma cell.
Highlights
MethodsPatient Tun was a 54-yr old man with a 3-yr history of chronic lymphocytec leukemia (CLL) whose leukocyte counts were consistently greater than 100,000/mm' when studied
An unusual B-cell proliferation was noted in an individual (Tun) which was characterized by the presence of two separate populations of chronic lymphocytec leukemia (CLL) cells staining on the surface and in the cytoplasm for either IgG(K) or IgA(u)
Utilizing an idiotypic antiserum prepared from the associated serum monoclonal IgG(K) protein the idiotype was detected on the surface and in the cytoplasm of both the IgG- and IgA-bearing cell populations. These observations are consistent with a common clonal origin and a switch mechanism involving IgG and IgA synthesis
Summary
Patient Tun was a 54-yr old man with a 3-yr history of CLL whose leukocyte counts were consistently greater than 100,000/mm' when studied. His serum contained a single IgG(K) monoclonal protein with a concentration of 30 mg/ml. An IgA monoclonal protein was not detected and no free light chains were present in serum or urine. The presence of spontaneous sheep red blood cell rosetting and the C'3 receptor were evaluated as described by Baxley et al . The presence of spontaneous sheep red blood cell rosetting and the C'3 receptor were evaluated as described by Baxley et al . [13]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
