It is suggested that various other cytokines produced by the clonal plasma cells, perhaps working in concert with each other as well as with VEGF and the myeloma proteins, mediate many of the features of POEMS syndrome. The other cytokines detected in, and suspected of contributing to, POEMS syndrome include interleukin 1β, interleukin 6, and TNFα. Nonetheless, it seems likely that some of these paraneoplastic factors, operating individually, make a major contribution to certain features of the disease. For example, VEGF, given its ability to stimulate blood vessel formation, would seem likely to be the major contributor to the pathologic hyper-vascularization changes seem in many tissues, such as lymph nodes, affected by POEMS syndrome. Diagnosis
The diagnosis of POEMS syndrome is based on meeting its two mandatory criteria, meeting at least one of its 3 other major criteria, and meeting at least one of its 6 minor criteria. These criteria are:
Mandatory major criteria
Plasma cell dyscrasia: This is evidenced by 1) the presence of a serum myeloma protein, typically an IgG or IgA isotype (occurs in nearly 100% of cases; in >95% of instances the myeloma proteins contain a λ chain that is restricted to either of two V lambda 1 subfamily members viz., IGLV1-40*01 and IGLV1-44*01 (see V lambda family); 2)   any, but often a small, increase above the normal value of <1.5% in the percentage of nucleated bone marrow cells that are clonal plasma cells (occurs ~67% of cases); and/or 3) presence of a plasma cell tumor (i.e.
The principal plasma proteins for drug binding are:
albumin
α1-acid glycoprotein
lipoproteinsSome drug interactions with warfarin are due to changes in protein binding. Cytochrome P450
Patients have abnormal metabolism by cytochrome P450 due to either inheriting abnormal alleles or due to drug interactions. Tables are available to check for drug interactions due to P450 interactions. Synergistic effects
An example of synergism is two drugs that both prolong the QT interval. Assessing causality
Causality assessment is used to determine the likelihood that a drug caused a suspected ADR. There are a number of different methods used to judge causation, including the Naranjo algorithm, the Venulet algorithm and the WHO causality term assessment criteria. Each have pros and cons associated with their use and most require some level of expert judgement to apply. An ADR should not be labeled as certain unless the ADR abates with a challenge-dechallenge-rechallenge protocol (stopping and starting the agent in question). The chronology of the onset of the suspected ADR is important, as another substance or factor may be implicated as a cause; co-prescribed medications and underlying psychiatric conditions may be factors in the ADR.Assigning causality to a specific agent often proves difficult, unless the event is found during a clinical study or large databases are used. Both methods have difficulties and can be fraught with error. Even in clinical studies some ADRs may be missed as large numbers of test individuals are required to find that adverse drug reaction. Psychiatric ADRs are often missed as they are grouped together in the questionnaires used to assess the population.