Hi Jennya
It’s very common that myeloma patients have low lymphocytes, outside the normal range.
It does not seem to reflect response to treatment but seems to be inherent to those patients’types of myeloma. Perhaps similarly many myeloma patients have low levels of their uninvolved immunoglobulins (eg if we have IgG myeloma, IgA and/or IgM being low, known as immunoparesis) .