IO2 Letters to the editor

subsequent to the aspiration of pus. Cultures for fungi (three weeks) and tubercle bacilli (eight weeks) yielded no growth.

Ten days after the aspiration the left neck was explored under general anaesthetic through a transverse neck incision at the level of the hyoid bone. The superficial part of the submandibular salivary gland was relatively normal but the deep part of the gland contained an enormous calculus which was excised with part of the gland. The dilated duct lining was partly squamous in type and had ulcerated with abscess formation in the surrounding tissue. A portion of the resected specimen was cultured as outlined above but no organisms were isolated. The patient's post-operative period was complicated by a minor pulmonary embolism from which there was a complete recovery.

Acute pyogenic lesions due to members of the genus Haemophilus are usually attributable to capsulated strains ofH. influenzae. The organism described here was non-haemolytic and dependent on V factor (NAD) and CO S for growth. Dependence on CO 2 did not decrease on successive subcultures. The strain approximates most closely to H. paraphrophilus by Kilian, 1 an uncommon cause of human infections.

First proposed as a new species by Zinnemann, Rogers, Frazer and Boyce, 2 H. paraphrophilus has been isolated from a variety of clinical sites ranging from brain abscess to the normal oropharynx. Zinnemann and colleagues concluded that the organism was part of the normal oral flora and was only occasionally pathogenic. That this appears to be true is evidenced by the paucity of reports in the literature incriminating it as a pathogen.

In this case the organism was isolated in pure culture though only after prolonged undisturbed incubation in CO2. It was presumably able to stimulate an acute inflammatory response only by virtue of the obstruction caused by the calculus.

Public Health Laboratory, K . A . V. Cartwright Gloucester Royal Hospital, Southgate Street, Gloucester

E.N. T. Department, M. Hardingham Gloucester Royal Hospital, Great Western Road, Gloucester

References

I. Kilian M. A taxonomic study of the genus Haemophilus with the proposal of a new species. ff Gen Microbiol I976; 93: 9-62.

2. Zinnemann K, Rogers KB, Frazer J, Boyce JMH. A new V-dependent Haemophilus species preferring CO S tension for growth and named Haemophilus paraphrophilus, nov.sp. J Path Bact I969; 96: 413-419.

Therapy for post-infective haemolysis

Sir, Although the anaemia in post-infective haemolysis is not usually sufficiently severe to warrant red cell transfusions, 1 Ellis and Smith demonstrate the occasional need for full supportive therapy, and emphasise the prevention of

Journal of Infection P l a t e I

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Plate I. X-ray of the neck showing swelling with dense calcification.

C A R T W R I G H T A N D H A R D I N G H A M (Facing p. •o2)

Letters to the editor Io3

adverse t ransfusion reactions. 2 In part icular it is poin ted out that the offending ant ibody in haemolysis associated with Mycoplasma pneumoniae infections has the specificity anti-I. T h e facilities provided by frozen red cell banks will enable clinicians faced with this hazardous situation to reduce the risk of pos t - t ransfus ion haemolysis. 1

T h e letter I stands for individual and almost every adult possesses the I antigen on his red cells. Howeve r a few adults have little or no I antigen, and are t e rmed I negative or i. Frozen red cell banks have I-negative donations which may be used to transfuse patients with auto- or allo-anti-I active at tempera tures close to body temperature. I t should be stressed however that a l though haemolysis in Mycoplasma pneumoniae infections is associated with anti-I , the offending ant ibody in cold haemagglutinin disease associated with infectious mononucleosis has the specificity anti-i.

Ellis and Smith kept their patient in a cubicle at 35 °C to reduce the hazard of post - t ransfusion haemolys i s ) Such an environment also has the meri t of reducing the danger of circulatory overloading. 1 Warming a recipient prior to t ransfusion opens up peripheral b lood vessels and reduces the amount of b lood in the pu lmonary circulation, thus diminishing the risk of circulatory overloading.

MRC Common Cold Unit, John Wallace Harvard Hospital, Coombe Road, Salisbury, Wilts, SP2 8BW

References I. Wallace J. Blood transfusion for clinicians. Edinburgh, London and New York: Churchill

Livingstone, 1977:151-154 and 256-257 . 2. Ellis ME, Smith CC. Therapy for post-infective haemolysis. (Letter). J Infect 1982; 4:

264-265.

Histiocytic medullary reticulosis

Sir, I wish to comment on the case report by Glover and colleagues (Journal (I982) 4 :175) of oppor tunis t ic Campylobacter bacteraemia in a patient with histiocytic medul lary reticulosis ( H M R ) .

T h e aetiology of H M R is unknown bu t a role for the Eps te in-Bar r virus (EBV) has been postula ted; 1,2,3,4 therefore the s tatement that infectious mononucleosis ( IM) had been excluded in their patient needs some elaboration because negative heterophile ant ibody tests do not exclude a pr imary EBV infection ;5 it would thus be of interest to know whether EBV-specific ant ibody tests had been per formed at any stage of this patient 's illness.

T h e second query involves the pancytopenia present ; the peripheral leucocyte count of 2"5 x i og/1 was unaccompanied by a 'd i fferent ia l ' ; since an absolute lymphopenia in H N I R has been noted by several workers 4, s, 7 it would be of interest to know the actual differential count and thus whether or not an absolute lymphopenia had been present.