Absolute CD4 and CD8 counts and CD4-to-CD8 ratios in eight patients with indolent B-cell chronic lymphocytic leukemia.

Background: There are some patients with B-cell chronic lymphocytic leukemia who exhibit an extraordinary natural resistance to this malignancy, which lasts for many years. In this study, we report the T-cell subset values and ratios in eight such patients.

Methods: Impath (New York, NY) evaluated immunophenotyping by performing flow cytometry. Absolute CD4 and CD8 counts and CD4:CD8 ratios were performed at Memphis Pathology Laboratory, Memphis, Tennessee.

Results: CD4 and CD8 counts and CD4:CD8 ratios were normal in all eight patients, in contrast to the suppressor cell proliferation and low helper-suppressor ratios that have been previously reported in other patients with B-cell chronic lymphocytic leukemia.

Conclusion: These results require further study to determine their significance. Implications for further study are discussed.

Key Words: B-cell chronic lymphocytic leukemia, CD4:CD8 ratios, natural resistance

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One of us (JDU) has been observing eight patients with B-cell chronic lymphocytic leukemia (B-CLL) who have exhibited a symbiotic relationship with this malignancy for 6 to 25 years (median, 14 years) with little or no treatment. We believe that there is more than just good fortune involved, and that these patients have a remarkable natural resistance to this disease. Natural resistance to B-CLL has been observed in the past, the best examples being in reports of spontaneous complete remissions, which some authors have estimated to occur in approximately 1% of patients with B-CLL. (1) The purpose of this article is to report the absolute CD4 and CD8 counts and CD4:CD8 ratios found in these eight patients, and to compare these results with those previously reported in other patients with ordinary B-CLL. T-cell subset values have not been reported previously in this type of B-CLL patient.

Patients and Methods

Methods

All initial diagnoses were made on the basis of examination of Wright-stained peripheral blood smears and bone marrow aspirates and hematoxylin and eosin-stained sections of bone marrow biopsy specimens. In all patients, the diagnosis of B-CLL was confirmed by immunophenotyping by flow cytometry of peripheral blood in 1999 or 2000 (performed by Impath, New York, NY). Absolute CD4 and CD8 counts and CD4:CD8 ratios were performed at Memphis Pathology Laboratory, Memphis, Tennessee, in 1999 or 2000.

Patient Characteristics

The age of patients at the time of diagnosis was 49 to 75 years (median, 56 years). As shown in Table 1, six patients (patients 2, 3, 4, 5, 7, and 8) had Rai Stage 0 B-CLL (2) at the time of initial diagnosis. Patient 5 progressed to Rai Stage I (cervical and axillary adenopathy) 10 years after initial diagnosis. The other five patients remained Rai Stage 0 throughout the entire period of observation (6-25 years; median, 16 years). Two patients (patients 1 and 6) had palpable bilateral inguinal adenopathy and splenomegaly by computerized axial tomography (not palpable) at the time of initial diagnosis and were assigned Rai Stage II. The inguinal adenopathy did not progress and their spleens never became palpable during 25 years (patient 1) and 10 years (patient 6) of observation.

As shown in Table 1, four patients (patients 1, 2, 3, and 7) received no treatment throughout the entire period of observation (8-25 years). Patient 5 received chlorambucil (Leukeran, GlaxoSmithKline, Research Triangle Park, NC) 2 mg po three times daily for 8 weeks in year 9 after initial diagnosis. Patient 8 received chlorambucil (same does) for 1 month in year 4 of observation, and again for 5 weeks in year 6 of observation. Patient 4 received chlorambucil (same dose) for 5 weeks in year 16 after initial diagnosis. Patient 6 received chlorambucil (same dose) for 4 weeks at the time of his initial diagnosis. Subsequently, he has received chlorambucil (same dose) for 3 to 5 weeks on six occasions (total of 7 months of therapy with chlorambucil in 10 years). These patients were seen for clinical evaluation, physical examination, and complete blood count every 2 to 4 months from the time of initial diagnosis. None of them had symptoms related to their B-CLL during the entire period of observation.

Results

The highest and lowest absolute lymphocyte counts, the year in which these occurred, and any therapy given are shown in Table 1. In four patients (patients 1, 2, 3, and 7), the absolute lymphocyte count became lower spontaneously during the period of observation (no treatment). In four cases (patients 4, 5, 6, and 8), the average absolute lymphocyte count trended upward slowly and progressively, and they received short courses of therapy with chlorambucil (see Patients and Methods section for details). Overall, these patients, who have had B-CLL for a combined total of 121 years, have received treatment with chlorambucil, 2 mg tid, for a combined total of 11 months. As shown in Table 1, absolute CD4 counts (normal, 400-2,120/[mm.sup.3]) ranged between 402 and 1,824/[mm.sup.3] (median, 796/[mm.sup.3]). Absolute CD8 counts (normal, 120-1,320/[mm.sup.3]) ranged between 51 and 905/[mm.sup.3] (median, 293/[mm.sup.3]). CD4:CD8 ratios (normal, 1.5-3.7) ranged between 1.78 and 9.43 (median, 2.79).

Discussion

In patients with B-CLL reported previously, changes occur in T-lymphocyte subsets that adversely affect the normal immune process. Most studies report a disproportionate proliferation of the suppressor cell (CD8) population that leads to a lowering of the helper-suppressor ratio (CD4:CD8 ratio). Most cases of Rai Stage 0 B-CLL reported show these changes, and the suppressor cell proliferation increases and helper-suppressor ratios become even lower as the stage of B-CLL advances. Reports indicate that the helper-suppressor ratio in Rai Stage 0 is usually in the range of 1, whereas in patients with Rai Stages III and IV the helper-suppressor ratio is usually 0.5 or below. In some studies, helper cell (CD4) counts have been reported to be lowered; in others, they were normal or even elevated. (3-8) There are, in addition, reports of a myriad of functional defects that appear in the T lymphocytes, including a marked increase in suppressor activity. (9-15) The end result in Rai Stages III and IV is a numerically distorted and functionally impotent T-lymphocyte system. At the same time this virtual paralysis of T-lymphocyte capacity is occurring, there is an unrestrained and rapid accumulation of B-CLL cells, and resistance to infection is severely impaired, resulting in median survival time plummeting from approximately 12 years in Rai Stage 0, to 1 to 2 years in Rai Stages III and IV.

The normal CD4 and CD8 counts (except for Patient 7, who actually had a low CD8 count) and normal CD4:CD8 ratios found in our eight patients are in sharp contrast to the abnormal numbers and low helper-suppressor ratios that have been reported in other patients with B-CLL in the past (see above). We recently reported a patient who exhibited the ultimate expression of natural resistance to B-CLL--a spontaneous remission. He had normal CD4 and CD8 counts and a normal CD4:CD8 ratio in the peripheral blood. An important remission-associated event in this patient was T-lymphocyte hyperplasia in his bone marrow, measured after spontaneous remission had occurred. (1) We are not contending that the normal T-cell subset counts and ratios are the cause of these patients' natural resistance to B-CLL, but are identifying them as important resistance-related events in these eight patients.

We acknowledge that a study including only eight patients asks more questions than it answers, and our intention in submitting this report is to make these findings available to others better positioned than we are for further study. These patients were selected for study because they have exhibited a potent natural resistance to B-CLL over many years. Four of these patients (patients 1, 2, 3, and 7) are bona fide examples of spontaneous regression of cancer, which was eloquently defined and discussed at the Conference on Spontaneous Regression of Cancer in 1976. This conference was held to "explore these experiments of nature with a new audacity in thinking, and to listen more attentively and closely to see if there is more to hear than meets the ear in these 'whispers of nature.'" (16) It is in this spirit that this report is submitted.

One avenue that we believe would be productive for further investigation is whether or not CD4 and CD8 counts and CD4:CD8 ratios would be valuable prognostic indicators in patients with B-CLL, as proposed by Hermann et al (4) in 1982. It would also be of great interest to know whether there is any correlation between CD4 and CD8 counts and ratios, and mutated versus unmutated immunoglobulin gene status or CD38 status. It is possible that progressive lowering of the CD4:CD8 ratio could serve as an early warning that the B-CLL is beginning to get the upper hand in the individual patient. Prospective study of a much larger group of patients would be necessary to examine this possibility.

Most importantly, the findings in these select patients raise the possibility that therapeutic measures designed to nurture or enhance the normal T-lymphocyte system, such as patient-specific vaccination, (17) taken in early B-CLL (Rai Stage 0, most Rai Stage I, and some Rai Stage II patients), when tumor burden is low, could delay or even prevent accumulation of an excessive tumor burden and perhaps interrupt the downward spiral in T-lymphocyte competence that is associated with severely shortened survival times in patients with Rai Stages III and IV B-CLL. We believe this would be an important avenue for further study. Finally, we believe that whatever value this report may have will depend entirely on the extent to which it stimulates others to take a new look at some old friends.

Conclusion

Study of CD4 and CD8 counts and CD4:CD8 ratios in eight patients who have exhibited a remarkable natural resistance to B-CLL are found to be normal. This is in sharp contrast to the suppressor cell proliferation and the low CD4:CD8 ratios previously reported by others in other patients with B-CLL. Further study will be necessary to determine whether CD4 and CD8 counts and ratios would be valuable prognostic indicators in B-CLL. Further study will also be necessary to determine whether therapeutic measures designed to nurture or enhance normal T-lymphocyte activity taken in early B-CLL would be effective in preventing or delaying progression to late stages.

A bargain is something you have to find a use for once you have bought
it.
--Benjamin Franklin

Table 1. Patient characteristics and results

                             Absolute
                         lymphocyte count
                         (per [mm.sup.3])
          Duration of    Highest  Lowest
Patient  B-CLL (a) (yr)   (yr)     (yr)    Rai Stage

1             25          42,000   8,000   II (b)
                          (1976)   (2000)
2             25          21,000   3,300   0
                          (1981)   (1999)
3             21           9,600   3,000   0
                          (1980)   (1999)
4             16          53,000   9,360   0
                          (2001)   (1986)
5             10          40,000  10,000   0 [right arrow] I
                          (2000)   (1992)
6             10          51,000  12,000   II (b)
                          (1991)   (2001)
7              8           8,000   2,000   0
                          (1994)   (2000)
8              6          47,000   5,500   0
                          (2000)   (1995)

                           Absolute     Absolute
          Duration of     CD4 count    CD8 count   CD4:CD8
Patient  B-CLL (a) (yr)     (per         (per      ratio    Treatment
                         [mm.sup.3])  [mm.sup.3])

1             25             402       135         2.98     None
2             25             924       243         3.8      None
3             21             523       201         2.8      None
4             16           1,699       890         1.9      Leukeran (b)
5             10           1,824       905         2.02     Leukeran (b)
6             10             697       417         1.78     Leukeran (b)
7              8             481        51         9.43     None
8              6           1,216       343         3.6      Leukeran (b)

(a) B-CLL, B-cell chronic lymphocytic leukemiq.
(b) See text.

Accepted May 30, 2003.

Copyright [c] 2004 by The Southern Medical Association

0038-4348/04/9703-0236

References

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10. Kay NE, Perri RT. Evidence that large granular lymphocytes from B-CLL patients with hypogammaglobulinemia down-regulate B-cell immunoglobulin synthesis. Blood 1989;73:1016-1019.

11. Ayanlar-Batuman O, Ebert E, Hauptman SP. Defective interleukin-2 production and responsiveness by T cells in patients with chronic lymphocytic leukemia of B cell variety. Blood 1986;67:279-284.

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RELATED ARTICLE: Key Points

* Some patients with B-cell chronic lymphocytic leukemia exhibit a remarkable natural resistance to this malignancy, which lasts for many years.

* CD4 and CD8 counts and CD4:CD8 ratios in eight such patients are normal, unlike the finding of lowered CD4:CD8 ratios in B-cell chronic lymphocytic leukemia patients studied in the past.

* Further study is necessary to determine the significance of these findings.

Jefferson D. Upshaw, Jr., MD, and Thomas R. Callihan, MD

From the Memphis Cancer Center and the Pathology Group of the Midsouth. Memphis, TN.

No financial support, no proprietary interest, no experimental results.

Reprint requests to Jefferson D. Upshaw, Jr., MD, 1068 Cresthaven Road, Suite 500, Memphis, TN 38119.