1149

proportion of cases these lymphomas are strikingly monomorphic. 2

Furthermore, a mixed high and low grade histology is by no meansuncommon. This category of gastrointestinal lymphoma sharesmany histological, phenotypic and functional properties withnormal MAL T3-S and is strikingly similar both in histology andclinical behaviour to low and high grade B cell lymphomas arising atother mucosal sites, but not to other extranodal lymphomas.Many of the histological features of MALT lymphomas relate toproperties other than simply the size and shape of cells. Thus, whilethere is no proof that these tumours arise from MALT, there is agood deal of circumstantial evidence that this is so. Moreover, thereis no other explanation for the favourable behaviour exhibited bythis group of lymphomas, of both low and high grade histology,when compared with those of peripheral lymph nodes. We agreethat Mediterranean lymphoma, although similar in many respectsto MALT lymphomas in Western countries,9 should retain its

separate identity, but Hall et al have omitted to include the highgrade form of this disease.The most significant "modem notion" relating to T cell

lymphomas of the gastrointestinal tract has surely been therecognition of the entity that is now known as "enteropathyassociated T cell lymphoma (EATCL).10," The T cells of thistumour-whether large, small, pleomorphic, or immunoblastic,and whether or not accompanied by eosinophils-arephenotypically distinctive.12 More importantly, EATCL is a

distinct clinical entity.The classification proposed by Hall et al serves no purpose. It is

not based on sound histological criteria, gives no biologicalinformation, and is of no clinical value. It is far too early to propose adefinitive classification of this enigmatic group of tumours.

However, prompted by the letter of Hall et al, and with somereluctance, we list here (table) the principal categories of primarygastrointestinal lymphomas as they are now understood:

B Cell

(1) Low grade B cell lymphoma of MALT(2) High grade B cell lymphoma of MALT, with or without evidence of a low

grade component(3) Mediterranean lymphoma (immunoproliferative small intestinal

disease), low grade, mixed, or high grade(4) Malignant lymphoma centrocytic (lymphomatous polyposis)(5) Burkitt like lymphoma(6) Other types of low or high grade lymphoma corresponding to peripheral

lymph node equivalents

T Cell

(1) Enteropathy associated T cell lymphoma (EATCL)(2) Other types unassociated with enteropathy

This list is broadly similar to that agreed by the panel of pathologistsresponsible for the workshop on gastrointestinal lymphomas held atthe first meeting of the European Association for Haemato-

pathology, in Geneva, in April, 1988.

Department of Histopathology,University Collegeand Middlesex School of Medicine,

London WC1E 6JJ

P. G. ISAACSON

JO SPENCER

Department of Pathology,University of Southampton D. H. WRIGHT

1 Stansfeld AG, Diebold J, Kapanci Y, et al. Updated Kiel classification for

non-Hodgkin’s lymphoma. Lancet 1988; i: 292-93.2. Myhre MH, Isaacson PG. Primary B-cell gastnc lymphoma—a reassessment of its

histogenesis J Pathol 1987; 152: 1-11.3 Isaacson PG, Spencer J, Finn T. Primary B-cell gastric lymphoma. Hum Pathol 1986;

17: 72-82.4. Spencer J, Finn T, Isaacson PG. Gut associated lymphoid tissue: a morphological and

immunocytochemical study of the human appendix. Gut 1985; 26: 672-795 Spencer J, Finn T, Pulford KAF, Mason DY, Isaacson PG. The human gut contains a

novel population of B lymphocytes which resemble marginal zone cells. Clin ExpImmunol 1985; 62: 607-12.

6. Hyjek E, Smith W, Isaacson PG. Primary B cell lymphoma of salivary glands and itsrelationship to myoepithelial sialadenitis (MESA). Hum Pathol 1988; 19: 766-76

7. Addis B, Hyjek E, Isaacson PG. Primary pulmonary lymphoma. a reappraisal of itshistogenesis and its relationship to pseudolymphoma in lymphoid interstitial

pneumonia Histopathology 1988; 13: 1-17.8 Hyjek E, Isaacson PG. Primary B cell lymphoma of the thyroid and its relationship to

Hashimoto’s thyroiditis. Hum Pathol (in press).

9. Isaacson P, Wright DH Malignant lymphoma of mucosa-associated lymphoid tissue:a distinctive type of B cell lymphoma Cancer 1983; 52: 1410-16.

10. Isaacson P, Wright DH. Intestinal lymphoma associated with malabsorption. Lancet1978; i 67-70

11. Isaacson PG, O’Connor NTJ, Spencer J, et al. Malignant histiocytosis of the intestine:a T-cell lymphoma Lancet 1985; ii: 688-91.

12. Spencer J, Cerf-Bensussan N, Jarry A, et al. Enteropathy-associated T cell lymphoma(malignant histiocytosis of the intestine) is recognized by a monoclonal antibody(HML-1) that defines a membrane molecule on human mucosal lymphocytes.Am J Pathol 1988; 132: 1-5

IS CAMPYLOBACTER PYLORI A ZOONOSIS?

SIR,-We agree with Dr Goodwin and colleagues (Oct 22, p 968)that serology on its own does not constitute final proof thatCampylobacter pylori is a zoonosis, and this was reflected in thequestion mark in the title of our Sept 24 paper.Endoscopy was done in only 28 individuals because those who

had a low level of antibody and were symptom-free were, naturally,unwilling to be subjected to this procedure. Nevertheless we believethis is the first prospective assessment of a serological test forC pylori. Our serological test was validated against endoscopy,culture, histology, and ’CP-test’ in a population other than abattoirworkers.l,2

Partial cross-reaction with C jejuni does occur with our ELISAtest, but after absorption of the serum with C jejuni, titres againstC pylori fall by about 7%, whereas titres against C jejuni fall by morethan 50%. There is thus very little cross-reaction against Cjejuniand this does not invalidate our result; after treatment the titreagainst C pylori fell but the titre against Cjejuni remained essentiallyunchanged. Also those patients who had the highest C pylori titres(the ones investigated by endoscopy) did not have the highest titresagainst Cjejuni. There may be cross-reaction with another, as yetunidentified, organism.We agree that more substantial proof of animals being a source of

C pylori is needed, and this will involve attempts to isolate thisorganism from their stomachs, which is what we are now

attempting.

Departments of Gastroenterologyand Microbiology,

Middlesex Hospital,London W1N 8AA,Department of Gastroenterology,VI Geriatric Section,M. Malpighi Hospital,Bologna, Italy,

and Charing Cross SunleyResearch Centre, London

DINO VAIRACLELIA D’ANASTASIO

JOHN HOLTONJOHN DOWSETTMARCO LONDEIPAUL SALMONLIONELLO GANDOLFI

1 Oderda G, Vaira D, Holton J, Dowsett JF, Ansaldi N. Serum pepsinogen I and IgGantibody to Campylobacter pylori in non specific abdominal pain in childhood. Gut(in press).

2. Vaira D, Holton J, Falzon M, et al Investigation of Campylobacter pylori associatedgastritis by histology, culture, urease test, brushings and antibody levels Ital JGastroenterol (in press).

HOME MEASUREMENT OF BLOOD PRESSURE

SIR,-Dr Koenigsberger (Sept 24, p 739) suggests that homeblood pressure kits are insufficiently reliable because it is not knownwhether they record phase IV or phase V diastolic pressure. Sincecommercially available devices, at least in Australia, monitorKorotkow sounds microphonically, it seems certain that they all usephase V: the sound shift at phase IV would not be detectable.Your Aug 13 editorial emphasises the considerable potential for

home blood pressure monitoring in circumventing the stress-

induced pressor response to a clinical environment. An additionalfactor is the likelihood that patients accustomed to taking their ownblood pressures are less likely to be stressed by a doctor doing thesame thing. The question of the reliability of home readingsremains, but in view of the demonstrable benefits to be gained, is ittoo much to hope that general practitioners and national heartassociations might cooperate in educating patients and in securingmanufacturing standards?

Department of Phy siology,University of Melboume.

Parkv ille, Victoria 3052, Australia CHRISTOPHER BELL