Patent ID: 8415110

Claim:
A method of detecting, monitoring or diagnosing a malignant plasma cell disease in an individual patient, said method comprising obtaining a first sample from said individual patient; contacting said first sample with at least one antibody, or a Fab or F(ab′) 2 fragment thereof, specific for the heavy chain class; contacting said first sample with light chain class antibodies, or a Fab or F(ab′) 2 fragments thereof, said light chain antibodies comprising antibodies specific for λ light chains and/or antibodies specific for κ light chains, wherein one class of antibodies selected from said heavy chain class and light chain antibodies (or their counterpart Fab or F(ab′)2 fragments thereof), is immobilized on a solid support and the other is labeled; removing unbound immunoglobins and free light chains; conducting an immunoassay on said first sample to determine for said individual patient a first ratio between the measured relative amounts of immunoglobulins having a heavy chain class bound to λ light chains, compared to immunoglobulins having the same heavy chain class but bound to κ light chains; comparing said first ratio to a second ratio, said second ratio comprising the relative amounts of immunoglobins having a heavy chain class bound to λ light chains, compared to immunoglobulins having the same heavy chain class but bound to κ light chains in a) a second sample obtained from an individual without the disease, or b) a second sample taken from said individual patient after said first sample or; comparing said first ratio to a threshold value obtained from population data analysis of measured ratios between the amounts of immunoglobulins having a heavy chain class bound to λ light chains, relative to immunoglobulins having the same heavy chain class but bound to κ light chains in samples obtained from individuals without the disease; wherein a deviation of said first ratio from said second ratio or said threshold value indicates the presence of a malignant plasma cell disease and/or the progression/regression of the disease.