CORRESPONDENCE 377

CORRESPONDENCE

LYMPHOCYTE SUBPOPULATIONS IN PATIENTS WITH UNTREATED PERNICIOUS ANAEMIA

To the Editor: Pernicious anaemia (PA) is generally held to be the result of an autoimmune injury. Alterations in the function and number of immunoregulatory T cells (helper/suppressor) are common in many autoimmune diseases and recently it has been suggested that the imbalance of subsets of lymphocyte may act as a cause of P A by. inducing an autoimmune injury of gastric mucosa ( 1 ) . Wodzinski et al (2) measured lymphocyte subpopulations and intrinsic factor antibodies in patients with megaloblastic anaemia who were under successful treatment with Vitamine Bt2 injections. The mean T4/T8 ratio vas found to be elevated because of a decrease in the percentage of suppressor cells in 8 of the 10 patients who had intrinsic factor antibodies in their serum. We have investigated blood lymphocytes and the distribution of subsets in 6 patients with untreated PA.

All patients had low serum Vitamin B12, mega- loblastic anaemia, atrophic gastritis, achlorhydria and absence of intrinsic factor (IF) secretion before and after pentagastrin. Blocking antibodies against IF were found in the sera of 2 patients, antibodies against parietal-cells in 3, and hypogammaglobulinaemia in 1. All the patients responded to i.m. hydroxycobalamin.

The lymphocyte subsets were indentified by the hybridome-produced monoclonal antibodies B1, T4, T8 and T3 (Coulter Immunology, Hialeah, FL), and Leu 7 (Becton-Dickinson, Mountain View, CA). The results are shown in Table 1. We could not demon- strate any alterations in the peripheral blood lympho- cyte subsets, either in percentage or in absolute count. Our patient 3 (with negative intrinsic factor antibodies)

TABLE I Lymphocyte subsets (%I in 6 untreated patients with pernicious anaemia

T4/T8 T3 T4 T8 Leu 7 B1 ratio

PATIENT 1 72 56 20 8 8 2.6 PATIENT 2 80 61 20 ND 6 3.0 PATIENT 3 80 68 16 I1 10 4.2 PATIENT 4 ND 50 16 ND ND 3.1 PATIENT 5 70 60 20 6 6 3.0 PATIENT 6 70 46 18 ND 4 2.4

Normal values in healthyadults(range) 60-75 47-58 17-30 6-15 6-14 1.8-3.1

ND: Not Done

had an increased TWT8 ratio and patient 6 had low B-lymphocyte count. Therefore, the T4/T8 imbilance could not be demonstrated. Unlike the patients in other studies (1,2), our patients had not previously been treated when we investigated their lymphocyte sub- populations. Further studies are needed to elucidate exactly the relevance of immunological abnormalities due to cellular-immune mechanisms in patients with PA.

References I . Imamura N, Fujimura K, Kurarnoto A. Lymphocyte

subpopulations in pernicious anemia. N Engl J Med 1984;311:56.

2. Wodzinski MA, Forrest MJ, Barnett D, Lawrence ACK. Lymphocyte subpopulations in patients with hydroxy- cobalamin responsive megaloblastic anemia. J Clin Pathol 1985;38:582-4.

Correspondence to: Jesus Soler, Angel Remacha, Merce Nieto, Enric Gimferrer Department of Haematology Hospital de la Santa Creu i Sant Pau Autonomous University of Barcelona St. Antoni M1 Claret, 167 08025-Barcelona Spain