Was a CSF specimen obtained and was electrophoresis performed in the CSF
specimen? What neurological symptoms did the patient have?
Tetraclonality cannot be defined by the number of narrow bands. There have
to be 4 different clones of plasma cells, each one secreting a different
immunoglobulin molecule (even if of the same class and type). Are these 4
bands of IgG kappa of the same subclass? Multiple narrow bands in
electrophoresis can be due to oligoclonal proteins, i.e., a more
restricted immunoglobulin distribution (e.g., only IgG1). Also, there can
be polymerization (or aggregation) of an immunoglobulin giving multiple
bands or breakdown of immunoglobulins either in light chains and heavy
chains or in other fragments (e.g., half-molecules). The key to calling an
immunoglobulin monoclonal (in electrophoresis or flow cytometry, for
example) is the reactivity with only one antibody to light chains, i.e.,
only kappa or lambda. Unfortunately, things are not always so simple. It
was found in urine that narrow bands that reacted only with anti-kappa
(and should have been called monoclonal proteins) were in fact polyclonal
light chains (as detected by 2 dimensional electrophoresis). The term
"ladder pattern" was coined for this finding by Harrison in 1991 (Clin
Chem).
In summary, what electrophoresis system was used? For IFE several
anti-lambda antisera should
be used and different dilutions should be tried to avoid excess of antigen
or so-called unreactive light chains. Finally, the molecular weight of
these proteins should be determined, to detect polymers (this is not that
easy to do). I think I read about a case of 4 M-proteins in serum and
definitely I read about 3 M-proteins (the term triclonal was used).
There is still a lot of confusion on calling immunoglobulins oligoclonal
in serum. Most of the papers are on oligoclonal immunoglobulins in CSF
(95% of papers from Medline with the word oligoclonal in the abstract).
The
recent (February 1999 issue of Archives of Pathol Lab Med) recommendations
of the CAP panel on testing for M-proteins did not clarify the confusion
that persist in literature in using terms such as monoclonal, oligoclonal,
minimonoclonal, and pseudo-oligoclonal proteins.
Please keep us informed about your findings.
Adrian Vladutiu
On Fri, 2 Apr 1999, R.W. Wulkan wrote:
> Dear collegue,
>
> Recently, we were somewhat puzzled by a 67 year old
> neurological patient. Serum protein electrophoresis showed several
> distinct bands in the gamma region, which on immunofixation proved to
> be IgG kappa bands. We have seen examples of multiple bands, but this
> time we have four bands. Has anyone experience with tetraclonalicity
> (I didn't know this word existed). Further details: serum protein 87
> g/L, tot.Ca 2.40 mmol/L, albumin unknown.
> Any comment welcome.
>
> Happy Easter
>
> Raymond Wulkan
> Zuiderziekenhuis
> Rotterdam
> The Netherlands
>
>
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|