ALBERT

Description: Pretreatment peripheral blood and/or bone marrow blasts from 90 adults with acute lymphoblastic leukemia (ALL) were analyzed as part of a prospective treatment protocol study. Specimens were tested by immunofluorescence cytofluorometry for reactivity with the following monoclonal antibodies (MoAbs): BA-1 (B cell antigen); T101, OKT11 (pan- T cell antigens [T]); 3A1 (T cell antigen); MCS-2 (myeloid antigen); J5 common ALL antigen (CALLA); BA4 (Ia antigen [Ia]); BA-2 (lymphohematopoietic antigen). Four major phenotypic groups were identified: B lineage ALL (BA-1+T-) (64%), T lineage ALL (T+BA-1-MCS-2- ) (13%), unclassified ALL (BA-1-MCS-2-CALLA-T-) (9%) and myeloid antigen ALL (MCS-2+CALLA-T-) (7%). An additional group of patients, miscellaneous ALL (7%), was comprised of cases with unusual marker profiles. In B lineage ALL, all cases tested were Ia+MCS-2-, and the vast majority were CALLA+ (84%). In T lineage ALL, 42% expressed CALLA or Ia positivity. In unclassified ALL, the predominant phenotype was Ia+BA-2+. In myeloid antigen ALL, two of four tested were 3A1+ and all cases evaluated were BA-1-. Patients with myeloid antigen ALL were older (median age, 66 years) than patients in the other groups. The T lineage ALL group had higher leukocyte counts (median WBCs, 183,000/microL) and an increased incidence of anterior mediastinal mass at presentation. All patients received identical induction therapy. In CALLA+B lineage ALL, 30 of 46 (65%) achieved a complete remission. While the number of patients evaluated was small, 9 of 9 CALLA-B- lineage ALL and only two of six myeloid antigen ALL cases responded with a complete remission. The data suggest that these MoAbs are useful in the characterization of adult ALL.

Description: In order to investigate the clinical significance of surface antigen analysis in acute myeloblastic leukemia (AML), the blasts from 196 patients with AML were analyzed prospectively with a panel of 16 monoclonal antibodies. The antibodies were selected to identify differentiation-associated antigens of either the myeloid lineage (MY9, PM-81, AML-2–23, MY7, MCS-1, MY8, Mo1, MY1, MY4, Mo2), T cell lineage (T101, T11), B cell lineage (B1, B4) or multiple lineages [J5 (CALLA), HLA-DR]. Independent morphological review and classification by French- American-British (FAB) criteria was performed in 161 of the 196 cases. One or more myeloid surface antigens were detected on the blasts of 195 cases, while B and T cell markers were detected on 0% to 2% of cases. When both blood and marrow samples were studied on the same patient, very few differences were noted between the antigenic profiles of the paired specimens. The frequency of expression of individual myeloid antigens ranged from 91% (PM-81) to 29% (Mo2). Expression of individual antigens was found to correlate significantly with several clinical parameters including FAB classification, cytochemical staining for alpha naphthyl acetate esterase, leukocyte count, and the presence of extramedullary disease at presentation. Two myeloid antigens (MY4 and MY7) predicted for a low rate of complete remission (CR) to standard induction chemotherapy. MY4+ cases (37% of the total population) had a CR rate of 53%, while M4- cases had a CR rate of 69% (P = .03). MY7+ cases (57% of the total population) had a CR rate of 55% while MY7- cases had a CR rate of 73% (P = .01). Neither MY4 nor MY7 antigen expression was correlated with patient age. Paired combinations of antigens were also examined. The [MY4- MY7-] phenotype was exhibited by 32% of all cases and was associated with an 82% CR rate while the CR rate of all other cases was 54% (P = .001). The expression of three antigens (HLA-DR, MY8, Mo1) was associated with a decreased continuous complete remission (P less than .05, median follow-up time of 19 months). Expression of MY8 antigen was also associated with decreased survival (P = .03). These results confirm earlier reports of antigenic heterogeneity in AML, and indicate that immunologically defined subgroups of AML patients which are of potential clinical significance can be identified.

Description: Pretreatment peripheral blood and/or bone marrow blasts from 90 adults with acute lymphoblastic leukemia (ALL) were analyzed as part of a prospective treatment protocol study. Specimens were tested by immunofluorescence cytofluorometry for reactivity with the following monoclonal antibodies (MoAbs): BA-1 (B cell antigen); T101, OKT11 (pan- T cell antigens [T]); 3A1 (T cell antigen); MCS-2 (myeloid antigen); J5 common ALL antigen (CALLA); BA4 (Ia antigen [Ia]); BA-2 (lymphohematopoietic antigen). Four major phenotypic groups were identified: B lineage ALL (BA-1+T-) (64%), T lineage ALL (T+BA-1-MCS-2- ) (13%), unclassified ALL (BA-1-MCS-2-CALLA-T-) (9%) and myeloid antigen ALL (MCS-2+CALLA-T-) (7%). An additional group of patients, miscellaneous ALL (7%), was comprised of cases with unusual marker profiles. In B lineage ALL, all cases tested were Ia+MCS-2-, and the vast majority were CALLA+ (84%). In T lineage ALL, 42% expressed CALLA or Ia positivity. In unclassified ALL, the predominant phenotype was Ia+BA-2+. In myeloid antigen ALL, two of four tested were 3A1+ and all cases evaluated were BA-1-. Patients with myeloid antigen ALL were older (median age, 66 years) than patients in the other groups. The T lineage ALL group had higher leukocyte counts (median WBCs, 183,000/microL) and an increased incidence of anterior mediastinal mass at presentation. All patients received identical induction therapy. In CALLA+B lineage ALL, 30 of 46 (65%) achieved a complete remission. While the number of patients evaluated was small, 9 of 9 CALLA-B- lineage ALL and only two of six myeloid antigen ALL cases responded with a complete remission. The data suggest that these MoAbs are useful in the characterization of adult ALL.

Description: In order to investigate the clinical significance of surface antigen analysis in acute myeloblastic leukemia (AML), the blasts from 196 patients with AML were analyzed prospectively with a panel of 16 monoclonal antibodies. The antibodies were selected to identify differentiation-associated antigens of either the myeloid lineage (MY9, PM-81, AML-2–23, MY7, MCS-1, MY8, Mo1, MY1, MY4, Mo2), T cell lineage (T101, T11), B cell lineage (B1, B4) or multiple lineages [J5 (CALLA), HLA-DR]. Independent morphological review and classification by French- American-British (FAB) criteria was performed in 161 of the 196 cases. One or more myeloid surface antigens were detected on the blasts of 195 cases, while B and T cell markers were detected on 0% to 2% of cases. When both blood and marrow samples were studied on the same patient, very few differences were noted between the antigenic profiles of the paired specimens. The frequency of expression of individual myeloid antigens ranged from 91% (PM-81) to 29% (Mo2). Expression of individual antigens was found to correlate significantly with several clinical parameters including FAB classification, cytochemical staining for alpha naphthyl acetate esterase, leukocyte count, and the presence of extramedullary disease at presentation. Two myeloid antigens (MY4 and MY7) predicted for a low rate of complete remission (CR) to standard induction chemotherapy. MY4+ cases (37% of the total population) had a CR rate of 53%, while M4- cases had a CR rate of 69% (P = .03). MY7+ cases (57% of the total population) had a CR rate of 55% while MY7- cases had a CR rate of 73% (P = .01). Neither MY4 nor MY7 antigen expression was correlated with patient age. Paired combinations of antigens were also examined. The [MY4- MY7-] phenotype was exhibited by 32% of all cases and was associated with an 82% CR rate while the CR rate of all other cases was 54% (P = .001). The expression of three antigens (HLA-DR, MY8, Mo1) was associated with a decreased continuous complete remission (P less than .05, median follow-up time of 19 months). Expression of MY8 antigen was also associated with decreased survival (P = .03). These results confirm earlier reports of antigenic heterogeneity in AML, and indicate that immunologically defined subgroups of AML patients which are of potential clinical significance can be identified.