50

Haematological course of ITP in patient with AIDS-relatedcomplex.

was positive to IgG without complement fixation. Maintenancetherapy consisted of danazol(400 mg daily) and rhesus antibodies(1000 µg weekly).

Blockage of the reticuloendothelial system (RES) is a possibleapproach to therapy in ITP; this non-invasive, temporary"chemical" splenectomy has been reported after administration ofhigh-dose intravenous gammaglobulin3 but the response in ourpatient was poor and transient. Excessive red blood cell destructioninterferes with platelet sequestration by the RES;" induction ofaccelerated RBC phagocytosis is possible with anti-Rh(D).sOur patient responded only after high doses of rhesus antibodies.

This response was accompanied by slight signs of haemolysis (a risein lactate dehydrogenase from 162 to 347 IU/1, a fall in haemoglobinfrom 150 to 123 g/1, and a fall in haptoglobin from 1 1 to 0-2 g/1).The platelet-associated IgG level then fell to pretreatment values;C3 and C4 remain normal. Tolerance was excellent. The remission

persisted for 2 weeks; the platelet count then fell but it has remainedabove 50 x 109/1 on maintenance therapy.

Interaction of antibody-coated RBC with macrophages is afeasible therapeutic approach in some cases of immune thrombo-cytopenia.

Medical Clinic Band Haematology Laboratory,

Groupe Hospitalier de la Timone,13385 Marseille, France

J. M. DURANDJ. R. HARLEJ. J. VERDOTP. J. WEILLERM. MONGIN

1. Walsh CM, Nardi MA, Karpatkin S. On the mechanism of thrombocytopenicpurpura in sexually active homosexual men. N Engl J Med 1984, 311: 635.

2. Schafer RW, Offit K, Macris NT, Horbar GM, Ancona L, Hoffman IR. Possible riskof steroid administration in patients at risk for AIDS. Lancet 1985; i: 934-35.

3. Fehr J, Hoffman V, Kappeler U. Transient reversal of thrombocytopenia in idiopathicthrombocytopenic purpura by high dose intravenous gamma globulin. N Engl JMed 1982; 306: 1254-58.

4. Shulman NR, Weinrach RS, Libre EP, Andrews HL. The role of the reticuloendo-thelial system in the pathogenesis of idiopathic thrombocytopenic purpura. TramAssoc Am Phys 1965; 78: 374-90.

5. Salama A, Kiefel V, Amberg R, Mueller-Eckhard C. Treatment of autoimmunethrombocytopenic purpura with rhesus antibodies. Blut 1984; 49: 29-35.

SIR,-Dr Baglin and colleagues report the successful treatmentof a patient with chronic ITP with a single dose of 100 Jlganti-Rh(D), thus confirming the efficacy of this treatment

introduced by us in 1983.1 Since then, we have treated in this wayover fifty children and adults with chronic or acute ITP.2-4 Therecommended dose is 40-50 µg anti-D Ig/kg body weight and twoor three intravenous and/or intramuscular injections are given. Theresponse has been good to excellent in about 70% of patients;children seem to respond better than adults do, and non-

splenectomised do better than splenectomised patients. The plateletincrement usually lasts less than 4 weeks but remissions of morethan 5 months have been observed in several cases, particularly afterrepeated treatment. We have never seen untoward reactions.

Haemoglobin values have almost always remained stable;laboratory signs of slight compensated haemolysis have often beennoted. The direct antiglobulin test became strongly positive(700-1700 IgG molecules per RBC), while the clearance of RBC, ifdetermined, was only slightly enhanced after administration ofanti-D.

Thus, it seems very likely that IgG-coated RBC can induce adiminution of the Fc-dependent clearing capacity of the RES,which might be more accurately described by a reversibleinteraction of sensitised RBC with macrophages rather than by therate of destructed cells. Although we have proposed a similarpathogenetic mechanism for the beneficial effect of high-dose IgGin ITP, low-grade sequestration of autologous RBC by high-doseIgG does not appear to be tenable. Whatever the mechanisms ofthese two therapeutic approaches may be at the molecular level,anti-Rh(D) can be recommended as a cheap and safe alternativetreatment in patients with ITP.

Institute of Clinical Immunologyand Blood Transfusion,

Justus Liebig University of Giessen,D-6300 Giessen, West Germany

C. MUELLER-ECKHARDTA. SALAMA

1. Salama A, Mueller-Eckhardt C, Kiefel V. Effect of intravenous immunoglobulin inimmune thrombocytopenia: Competitive inhibition of rericuloendothelial systemfunction by sequestration of autologous red blood cells? Lancet 1983; ii: 193-95.

2. Salama A, Kiefel V, Amberg R, Mueller-Eckhardt C. Treatment of autoimmunethrombocytopenic purpura with rhesus antibodies (anti-Rh0(D)). Blut 1984; 49:29-35.

3. Salama A, Kiefel V, Mueller-Eckhardt C. Effect of IgG anti-Rho(D) in adult patientswith chronic autoimmune thrombocytopenia. Am J Hematol (in press).

4. Becker T, Küenzlen E, Salama A, et al. Treatment of childhood idiopathicthrombocytopenic purpura with rhesus antibodies (anti-D). Eur J Paediatr (inpress).

WHAT’S IN AN UNRIPE COCONUT?

SIR,-Was your note (March 1, p 515) based on our study’ ofcoconut "water" in Tanzania? The unripe nuts contain fluid whichis consistently poor in sodium, chloride, and bicarbonate and rich inpotassium, calcium, and magnesium by comparison with WHOrecommended oral rehydration solution (ORS) (see table). Further-

ELECTROLYTE COMPOSITION (mmol/1) OF UNRIPE COCONUTWATER AND ORAL REHYDRATION SOLUTION

more, the fluid is acid and could theoretically worsen the potentiallyacidotic state of the patient with diarrhoea. The frequent morbidityand mortality from acute diarrhoeal diseases has stimulated thesearch for other cheap, effective, and safe alternatives to ORS.Coconuts are abundant in many developing countries, and the fluidfrom unripe coconuts has been drunk by healthy individuals withno ill-effects (apart from a dramatic diuresis). However, theelectrolyte composition of this fluid makes it potentially dangerousfor children with acute diarrhoea.

Academic Department of Child Health,Queen Elizabeth Hospital for Children,London E2 8PS ABEL E. MSENGI

***We apologise to Dr Msengi and his colleagues for omitting thatreference.-ED. L.

1. Msengi AE, Mbise RL, Msuya PM, Amsi DM. The biochemistry of water fromunripe coconuts obtained from two localities in Tanzania. E Afr Med J 1985; 62:725.