The influence of H-2 genetic factors on the development of benign monoclonal gammopathy in ageing H-2 congenic C57BL and BALB mice.

The role of H-2 genetic factors in the development of benign monoclonal gammopathy (BMG) was investigated in six H-2 congenic C57BL and BALB strains (C57BL/10.ScSn and BALB.B: H-2b; B10.D2 and BALB/c: H-2d; B10.BR and BALB.K: H-2k) during ageing. The frequencies of homogeneous immunoglobulins (H-Ig), both single and multiple, in the three C57BL strains were higher than those in the corresponding three BALB strains. No relationship was found with a particular H-2 haplotype. The most frequent H-Ig isotype within the C57BL strains was IgG2a, within BALB.B and BALB.K mice IgG3 and in BALB/c mice IgG1. Categorization of the monoclonal gammopathies (MG) on the basis of their origin showed a single transient monoclonal B-cell proliferation in 2-5% and 3-9% of the C57BL and BALB mice positive for H-Ig, respectively. Multiple myeloma or B-cell lymphoma were found to be responsible for about 1% of the paraproteinaemias in all strains. Persistent, non-progressive MG, most likely BMG, was detected in 70-81% and 39-46% of the C57BL and BALB mice positive for H-Ig, respectively. The remaining 14-24% and 50-58% of the, respectively, C57BL and BALB mice positive for H-Ig could not be evaluated in time. The H-2 haplotypes under investigation were not associated with the onset, occurrence, multiplicity, persistence or isotype of the MG developing in these H-2 congenic C57BL and BALB strains during ageing.