Clinical Significance of Low-Positive Troponin I by AxSYM and ACS:180

Abstract

We describe 9 well-characterized cases of B-cell non-Hodgkin lymphoma (NHL) that showed aberrant expression of T-cell-associated antigens by 2-color flow cytometry. Cases were as follows: chronic lymphocytic leukemia/small lymphocytic lymphoma, 4; follicle center cell lymphoma, 2; mantle cell lymphoma, 1; and diffuse large B-cell lymphoma, 2. CD2 was the most commonly expressed antigen (5 cases). CD8 and CD7 were identified in 2 cases each, including 1 case that expressed both CD7 and CD4. The disease course and response to treatment were compatible with the type and stage of lymphoma. No unusually aggressive behavior was noted in any case. A control group of 59 cases of benign lymph nodes analyzed during the same period showed no aberrant expression of T-cell-associated antigens; thus, such expression is not a feature of benign lymphoid proliferations. Study of these B-cell lymphomas may prove invaluable to study aberrant activation of silent or repressed T-cell differentiation genes. CD2-expressing B-cell NHLs may represent clonal expansion of CD2+ B lymphocytes that normally constitute a small fraction of peripheral B lymphocytes and should not be confused with composite B- and T-cell lymphomas. Unless aggressive behavior is noted consistently, no aggressive treatment is justified.

Troponin I in Patients without Chest Pain

“…Indeed, cTnI assays are currently not standardized (28 ) and produce variable results, especially in the low-positive range. Preliminary data collected by our group (14 ) and others (22 ) indicated that the detection rate of cTnI in patients with heart failure is highly variable among different commercial assays. In the current study, a commercial cTnI assay was used that has previously been found to detect the low cTnI concentrations that circulate in patients with unstable heart failure (14 ).…”

“…Preliminary data collected by our group (14 ) and others (22 ) indicated that the detection rate of cTnI in patients with heart failure is highly variable among different commercial assays. In the current study, a commercial cTnI assay was used that has previously been found to detect the low cTnI concentrations that circulate in patients with unstable heart failure (14 ). The performance of this assay may be different at other cutoffs and in patient populations that present with classic symptoms of ACS, such as CP (29 ).…”

Clinical and prognostic significance of aberrant T-cell marker expression in 225 cases ofde novodiffuse large B-cell lymphoma and 276 cases of other B-cell lymphomas

“…Carulli et al [13] reported eight patients with non-Hodgkin lymphoma showing aberrant expression of CD8 in 951 bone marrow samples, but that study was sharply biased in patient selection toward lymphomas with bone marrow invasion, such as CLLs/SLLs. In other studies [13, 17, 18] using more than 100 cases, variable histological classification, not the current WHO criteria, was applied, which does not represent the accurate distribution of non-Hodgkin lymphoma.…”

Falsely Elevated Cardiac Troponin I Levels

“…Using this method, cTnI was reduced by 98.5%, resulting in a level which was within the normal range in our laboratory. 13 Newer assays incorporate these methods of reducing spuriously elevated levels. The new Abbott AxSYM troponin I ADV assay used to test our patient's serum is one of these; it incorporates a preincubation step as well as three separate monoclonal antibodies to increase specificity.…”

“…Although these new assays can be successful in removing most of the interference present in plasma, in rare instances the blocking agent itself can cause a falsely elevated cTnI level through a process not well understood and requiring further study. 6,13 …”